Joint interpretation of geoelectrical and volatile organic compounds data: a case study in a hydrocarbons contaminated urban site

array:23 ["pii" => "S0016716914714990" "issn" => "00167169" "doi" => "10.1016/S0016-7169(14)71499-0" "estado" => "S300" "fechaPublicacion" => "2014-04-01" "aid" => "71499" "copyright" => "Universidad Nacional Autónoma de México" "copyrightAnyo" => "2014" "documento" => "article" "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/" "subdocumento" => "fla" "cita" => "Geofisica Internacional. 2014;53:183-98" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 1383 "formatos" => array:3 [ "EPUB" => 39 "HTML" => 936 "PDF" => 408 ] ] "itemSiguiente" => array:18 [ "pii" => "S0016716914715004" "issn" => "00167169" "doi" => "10.1016/S0016-7169(14)71500-4" "estado" => "S300" "fechaPublicacion" => "2014-04-01" "aid" => "71500" "copyright" => "Universidad Nacional Autónoma de México" "documento" => "article" "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/" "subdocumento" => "fla" "cita" => "Geofisica Internacional. 2014;53:199-210" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 1317 "formatos" => array:3 [ "EPUB" => 28 "HTML" => 912 "PDF" => 377 ] ] "en" => array:11 [ "idiomaDefecto" => true "titulo" => "Geological and geophysical data integration for delimitation of mineralized areas in a supergene manganese deposits" "tienePdf" => "en" "tieneTextoCompleto" => "en" "tieneResumen" => array:2 [ 0 => "es" 1 => "en" ] "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "199" "paginaFinal" => "210" ] ] "contieneResumen" => array:2 [ "es" => true "en" => true ] "contieneTextoCompleto" => array:1 [ "en" => true ] "contienePdf" => array:1 [ "en" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "f0005" "etiqueta" => "Figure 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1140 "Ancho" => 1181 "Tamanyo" => 222753 ] ] "descripcion" => array:1 [ "en" => "Location of the area of study, with positioning of lines of acquisition of geophysical data in the area of mining of manganese mineral." ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "César Augusto Moreira, Mario Rezende Borges, Glauber Matheus Lira Vieira, Walter Malagutti Filho, Mariana Aparecida Fernándes Montanheiro" "autores" => array:5 [ 0 => array:2 [ "nombre" => "César" "apellidos" => "Augusto Moreira" ] 1 => array:2 [ "nombre" => "Mario" "apellidos" => "Rezende Borges" ] 2 => array:2 [ "nombre" => "Glauber Matheus" "apellidos" => "Lira Vieira" ] 3 => array:2 [ "nombre" => "Walter" "apellidos" => "Malagutti Filho" ] 4 => array:2 [ "nombre" => "Mariana Aparecida" "apellidos" => "Fernándes Montanheiro" ] ] ] ] ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0016716914715004?idApp=UINPBA00004N" "url" => "/00167169/0000005300000002/v2_201505081358/S0016716914715004/v2_201505081358/en/main.assets" ] "itemAnterior" => array:18 [ "pii" => "S0016716914714989" "issn" => "00167169" "doi" => "10.1016/S0016-7169(14)71498-9" "estado" => "S300" "fechaPublicacion" => "2014-04-01" "aid" => "71498" "copyright" => "Universidad Nacional Autónoma de México" "documento" => "article" "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/" "subdocumento" => "fla" "cita" => "Geofisica Internacional. 2014;53:163-81" "abierto" => array:3 [ "ES" => true "ES2" => true "LATM" => true ] "gratuito" => true "lecturas" => array:2 [ "total" => 1298 "formatos" => array:3 [ "EPUB" => 25 "HTML" => 843 "PDF" => 430 ] ] "en" => array:11 [ "idiomaDefecto" => true "titulo" => "A multivariate Bernstein copula model for permeability stochastic simulation" "tienePdf" => "en" "tieneTextoCompleto" => "en" "tieneResumen" => array:2 [ 0 => "es" 1 => "en" ] "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "163" "paginaFinal" => "181" ] ] "contieneResumen" => array:2 [ "es" => true "en" => true ] "contieneTextoCompleto" => array:1 [ "en" => true ] "contienePdf" => array:1 [ "en" => true ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "f0040" "etiqueta" => "Figure 8" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr8.jpeg" "Alto" => 1081 "Ancho" => 1087 "Tamanyo" => 130538 ] ] "descripcion" => array:1 [ "en" => "Scatter plot and histograms of VS Meas and K (Simulated values)." ] ] ] "autores" => array:2 [ 0 => array:2 [ "autoresLista" => "Victor Hernández-Maldonado, Martín Díaz-Viera" "autores" => array:2 [ 0 => array:2 [ "nombre" => "Victor" "apellidos" => "Hernández-Maldonado" ] 1 => array:2 [ "nombre" => "Martín" "apellidos" => "Díaz-Viera" ] ] ] 1 => array:2 [ "autoresLista" => "Arturo Erdely" "autores" => array:1 [ 0 => array:2 [ "nombre" => "Arturo" "apellidos" => "Erdely" ] ] ] ] ] "idiomaDefecto" => "en" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0016716914714989?idApp=UINPBA00004N" "url" => "/00167169/0000005300000002/v2_201505081358/S0016716914714989/v2_201505081358/en/main.assets" ] "es" => array:17 [ "idiomaDefecto" => true "titulo" => "Joint interpretation of geoelectrical and volatile organic compounds data: a case study in a hydrocarbons contaminated urban site" "tieneTextoCompleto" => true "paginas" => array:1 [ 0 => array:2 [ "paginaInicial" => "183" "paginaFinal" => "198" ] ] "autores" => array:2 [ 0 => array:4 [ "autoresLista" => "Omar Delgado-Rodríguez, David Flores-Hernández, Myriam A. Amezcua-Allieri, Andrés Rosas-Molina, Salvador Marín-Córdova" "autores" => array:5 [ 0 => array:4 [ "nombre" => "Omar" "apellidos" => "Delgado-Rodríguez" "email" => array:1 [ 0 => "odelgado@imp.mx" ] "referencia" => array:1 [ 0 => array:2 [ "etiqueta" => "*" "identificador" => "cor0005" ] ] ] 1 => array:2 [ "nombre" => "David" "apellidos" => "Flores-Hernández" ] 2 => array:2 [ "nombre" => "Myriam A." "apellidos" => "Amezcua-Allieri" ] 3 => array:2 [ "nombre" => "Andrés" "apellidos" => "Rosas-Molina" ] 4 => array:2 [ "nombre" => "Salvador" "apellidos" => "Marín-Córdova" ] ] "afiliaciones" => array:1 [ 0 => array:2 [ "entidad" => "Instituto Mexicano del Petróleo (IMP), Lázaro Cárdenas Norte 152, San Bartolo Atepehuacan, 07730 México D.F." "identificador" => "aff0005" ] ] "correspondencia" => array:1 [ 0 => array:3 [ "identificador" => "cor0005" "etiqueta" => "*" "correspondencia" => "Corresponding author:" ] ] ] 1 => array:3 [ "autoresLista" => "Vladimir Shevnin" "autores" => array:1 [ 0 => array:2 [ "nombre" => "Vladimir" "apellidos" => "Shevnin" ] ] "afiliaciones" => array:1 [ 0 => array:2 [ "entidad" => "Moscow State University Geological Faculty Department of Geophysics Leninskie Gory, 119991 Moscow, Russia." "identificador" => "aff0010" ] ] ] ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:7 [ "identificador" => "f0045" "etiqueta" => "Figure 9" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr9.jpeg" "Alto" => 854 "Ancho" => 1221 "Tamanyo" => 74157 ] ] "descripcion" => array:1 [ "es" => "BTEX ratio of free-phase gasoline samples." ] ] ] "textoCompleto" => "<a name="p184"></a>IntroductionHydrocarbons are among the main factors of geological medium contamination. The effectiveness of electrical methods for the characterization, on surface and depth, of oil contaminated plumes has been reported by several authors (<a class="elsevierStyleCrossRef" href="#bib0190">Vanhala, 1997</a>; Modin et al., <a class="elsevierStyleCrossRef" href="#bib0120">1997</a>; Atekwana et al., <a class="elsevierStyleCrossRef" href="#bib0020">2001</a>; Osella et al., <a class="elsevierStyleCrossRef" href="#bib0135">2002</a>; Delgado-Rodríguez et al., <a class="elsevierStyleCrossRef" href="#bib0030">2006</a>; <a class="elsevierStyleCrossRef" href="#bib0035">2006a</a>). Just after contamination, a high resistivity anomaly delimits the contaminated zone. Oil contaminants cause changes in physical, chemical and biological properties of soil (<a class="elsevierStyleCrossRef" href="#bib0155">Sauck, 2000</a>; Atekwana et al., <a class="elsevierStyleCrossRef" href="#bib0020">2001</a>), mainly during the first four to six months after contamination. Abdel-Aal et al. (<a class="elsevierStyleCrossRef" href="#bib0005">2004</a>) found some important details on biodegradation process and changes in the electrical properties of contaminated zones. They demonstrated that the decrease of resistivity in soil contaminated by degraded hydrocarbons is mainly related to high surface conductivity in the pores of the affected rocks. Thus, the low resistivity anomalies are associated to the existence of mature hydrocarbon contamination. Electrical Resistivity Tomography (ERT) and Electromagnetic Profiling (EMP) are effective tools to mapping low resistivity anomalies caused by hydrocarbon contamination (Shevnin et al., <a class="elsevierStyleCrossRef" href="#bib0165">2005</a>).ERT is applied in order to obtain a geoelectrical image of the sub-surface using electrical measurements made along profile at the surface. The application of ERT method is based on apparent resistivity determination with the help of linear array (e.g. Dipole-Dipole, Wenner-Schlumberger) of many electrodes connected to resistivity equipment. Resistivity data are then processed to obtain a resistivity cross-section (<a class="elsevierStyleCrossRef" href="#bib0105">Loke, 2013</a>). As a result of interpretation, true layers resistivity and their thickness are estimated.The application of EMP method involves measuring the response of the subsurface to an electromagnetic field. An electromagnetic field is generated by a transmitter antenna, inducing eddy currents within the ground. These induced current generate a secondary magnetic field. Both primary and secondary magnetic fields are measured in a receiver antenna. The ground conductivity due to geological characteristics, conductive materials (metal objects) and contaminants can be calculated from the ratio of the secondary and primary magnetic fields (<a class="elsevierStyleCrossRef" href="#bib0085">Keller and Frischknecht, 1966</a>). The EMP results, although not providing detailed lithology (layers and their thicknesses) information, can quickly determine the horizontal changes in soil apparent conductivity (e.g. hydrocarbon contamination plume) at different study depths. The electromagnetic measurements are sensitive to buried elongated conductors such as metallic pipes, electric lines, sanitary sewer, etc. These are usually recognized by the large meter fluctuations which occur in short distance. When the antennas are oriented perpendicular to the elongated conductor’s axis, a minimum conductivity value will be registered (reaching negative values). When the antennas are parallel and close to the conductor’s axis, conductivity values will have a maximum (<a class="elsevierStyleCrossRef" href="#bib0055">Geonics Limited, 2010</a>). In this work, as part of the survey technique, to evaluate the magnitude of electromagnetic interference from metal objects in EMP measurements, soil conductivity measurements were performed to two orthogonal directions of the antennas.Volatile organic compounds (VOC) are the most common contaminants encountered at hydrocarbon contaminated sites. VOC survey is applicable under a variety of geological setting. Accurate VOC determinations are needed to assess the extent of contamination to make decisions for appropriate remedial action. The evaluation of subsurface organic vapors is based on the physical phenomena of hydrocarbons volatilization given by the Henry law (<a class="elsevierStyleCrossRef" href="#bib0095">Lin and Chou, 2006</a>), as well as the site characteristics. It has been demonstrated that the analysis of gases or vapors is a good screening technique in hydrocarbon contaminated sites, with GWT depths between 2 to 10m (<a class="elsevierStyleCrossRef" href="#bib0010">API, 1991</a>; Ochoa et al., <a class="elsevierStyleCrossRef" href="#bib0125">2007</a>). Determination of VOC is usually performed in situ using a photoionization detector. Using this equipment, it is possible to detect a wide range of compounds in the gasoline to diesel range.As a result of digging for a water cistern in a basement of an apartment building, a gasoline spill was detected. ERT and EMP methods were applied, as well as VOC measurements, in order to define the contamination plume and to guide the sampling activities. Through the application of the VOC, ERT and EMP methods, it was possible to calculate the dimensions of the affected area. Laboratory analyses of free-product samples suggest the existence of several contamination events with the presence of recent and mature hydrocarbon contaminants.Site backgroundThe site is located in a popular neighborhood of Mexico City between 2,240 and 2,244 m.a.s.l. The geological composition of the site belongs <a name="p185"></a>to the sedimentary Mexico City basin and Texcoco ex-lake’s west shore (Marín-Córdova et al., <a class="elsevierStyleCrossRef" href="#bib0110">1986</a>). The stratification sequence showed low permeability clay and silt within fine and medium sand lenses. The groundwater table (GWT) was between 3.75 and 5.00m in the central and northern portions of the site, meanwhile, in the southern portion, near to gas station, the GWT can reach up to 9.00m depth. The permeability coefficient rate was 1.0×10-6 to 1.0×10-7cm/s (low permeability).A paved (main) street runs from southwest to northeast along 350m (<a class="elsevierStyleCrossRef" href="#f0005">Figure 1</a>). As a result of digging for a water cistern in a basement of an apartment building, a hydrocarbon spill with gasoline-like odor from a thin layer at an approximate depth of 5m was detected. The spill point is about 100m from a gas station, and about 50m from small factories with solvents and fuel storage tanks, indicating the probable existence of active contamination sources (<a class="elsevierStyleCrossRef" href="#f0005">Figure 1</a>). Indirect methods were applied to map the contaminated zones and to select the soil boring locations, defining a study area of 5.3 ha.<elsevierMultimedia ident="f0005"></elsevierMultimedia>Application of geoelectrical and VOC methods: configuration of the contamination plumeApplication of VOC measurementsSubsurface vapors were measured in situ to assess the content of VOC. The methodology to measure VOC has been tested and improved since 1992 to allow a rapid measurement (screening) of the most likely occurrence and distribution of hydrocarbons in the subsurface and thus select the sites to perform the drilling and soil sampling. Sampling equipment including a specialized hammer and a hammer sampler probe, allows by vacuum, the extraction of vapor from subsoil. VOC content in subsoil can then be determined using a portable photoionization detector (PID), which can measure concentrations from ppb to up to 10,000 ppm. Since the presence of VOC in the subsurface originated from the hydrocarbons contaminants are quantified, this method could be considered as semi-indirect. VOC were measured at 91 selected points.<a name="p186"></a>Application of ERT methodThree ERT parallel profiles were performed on Main Street (<a class="elsevierStyleCrossRef" href="#f0005">Figure 1</a>) in order to obtain resistivity anomalies associated with the presence of hydrocarbon-contaminated soils. A total of 64 ERT measurements points were settled. ERT survey was carried out using a great number (~50) of electrodes placed along each profile with a constant interval of 4m, using AB/2 spacing of a Wenner-Schlumberger array from 6 to 42m, ensuring a maximal study depth of 15m. Spacing between sounding centers was 8m.Application of EMP methodUsing the EM31-MK2 equipment (<a class="elsevierStyleCrossRef" href="#bib0055">Geonics Limited, 2010</a>), the horizontal changes in soil apparent conductivity for maximal study depth of 6m is determined. Taking into account that in the most of the site the local GWT depth varies between 3.75m – 5.00m, it is feasible to use the EM31-MK2 equipment to detect the hydrocarbon contamination zones in soil, subsoil and groundwater, while in the southern end of the site (GWT depth=9.00m), EMP is feasible to detect the contamination in soil and subsoil, but not in the groundwater. The EMP survey was carried out considering the electromagnetic interference of the buried elongated conductors. According to our work experience using EM31-MK2 in urban and industrial sites (<a class="elsevierStyleCrossRef" href="#bib0065">IMP 2006</a>; <a class="elsevierStyleCrossRef" href="#bib0070">2006a</a>; <a class="elsevierStyleCrossRef" href="#bib0075">2008</a>; <a class="elsevierStyleCrossRef" href="#bib0080">2013</a>; Mendez-Velarde et al., <a class="elsevierStyleCrossRef" href="#bib0115">2012</a>), when the difference between conductivity values recorded to two orthogonal directions of the antennas is more than 10%, the EMP station is rejected and a new measuring point is selected, otherwise the average value can be used for the data reduction. In this way, we ensured that variations in the electromagnetic field are given only by variations in soil conductivity. After removing the measurement points affected by electromagnetic noise, 306 EMP data were recorded and an apparent resistivity map was made.Results and discussionThe results of the application of ERT, EMP and VOC methods were processed using software SURFER 8 (<a class="elsevierStyleCrossRef" href="#bib0060">Golden Software Inc., 2002</a>) with minimum curvature algorithm. The minimum curvature gridding provides reasonable maps with satisfactory smoothing of the field lines (<a class="elsevierStyleCrossRef" href="#bib0025">Briggs, 1974</a>), widely used in the earth sciences (<a class="elsevierStyleCrossRef" href="#bib0140">Ontario Geological Survey, 2003</a>; Orfanos and Apostolopoulos, <a class="elsevierStyleCrossRef" href="#bib0145">2012</a>), including geoelectric methods (Korhonen et al., <a class="elsevierStyleCrossRef" href="#bib0090">2005</a>; <a class="elsevierStyleCrossRef" href="#bib0180">Siemon, 2009</a>).VOC data interpretationThere are no national or international normative values that include normal or natural conditions of VOC for hydrocarbon contaminated soils. However, it has been observed that an anomalous value (greater than background) is evidence of contamination phenomena (<a class="elsevierStyleCrossRef" href="#bib0015">Arpel, 1992</a>). Fischer et al. (<a class="elsevierStyleCrossRef" href="#bib0050">1996</a>) studied a gasoline-contaminated site and they considered that VOC=21±2 ppm correspond to low contamination levels. Based on our experience (Ochoa et al., <a class="elsevierStyleCrossRef" href="#bib0130">2002</a>; Delgado-Rodríguez et al., <a class="elsevierStyleCrossRef" href="#bib0030">2006</a>, Mendez-Velarde et al., <a class="elsevierStyleCrossRef" href="#bib0115">2012</a>), we had determined that in hydrocarbons contaminated sites VOC values greater than 20 ppm are associated with presence of hydrocarbons, either as free product, absorbed in the subsurface or dissolved in groundwater.Fresh gasoline contamination presents high VOC (>20 ppm) concentration. Low VOC (<20 ppm) values could indicate the presence of clean soil or soil contaminated by mature hydrocarbons. <a class="elsevierStyleCrossRef" href="#f0010">Figure 2</a> shows some plumes with high VOC concentrations (dark zones, <a class="elsevierStyleCrossRef" href="#f0010">Figure 2</a>), indicating the presence of fresh contaminants in the subsoil; one of them possibly related to the gas station.<elsevierMultimedia ident="f0010"></elsevierMultimedia>In sites with an active contamination source it is possible to have both degraded contaminants (low VOC values) and fresh contaminants (high VOC values). In the spill point, such as in zone with clean soil, low VOC values are observed, indicating the possible existence of degraded hydrocarbon contaminants in the subsoil in zones with low values of VOC. Because of this, ERT and EMP methods are applied since they are effective for mapping mature contamination plumes.Statistical analysis of ERT data<a class="elsevierStyleCrossRef" href="#f0015">Figure 3</a> shows the statistical distribution (apparent resistivity vs. AB/2 distances) from 64 ERT measurements points. The legend represents the occurrence frequency values. In general, the apparent resistivity values are below of 20Ohm.m, even in the vadose zone (minimal depth of GWT is 3.75m), which means the clay content in soil is significant at different study depths. The mean curve (curve H, <a class="elsevierStyleCrossRef" href="#f0015">Figure 3</a>) characterizes the subsurface up to 15m depth by a three layer curve (type H) with low resistivity contrast. In most of the SEV, the resistivity decreases from 10 to 7.8Ohm.m (first and second layer) which marks the transition from a semi-saturated to saturated clayey sediments, respectively, followed by a third layer (AB/2>30m) with <a name="p187"></a><a name="p188"></a>lower clay content (ρa~9Ohm.m). Apparent resistivity values below 6.4Ohm.m are outlined in a cloud of data (dashed line contour, zone C, <a class="elsevierStyleCrossRef" href="#f0015">Figure 3</a>), indicating the presence of low resistivity anomalies (mature contamination) for some ERT points, mainly for AB/2>10m or study depth≥5m (second layer).<elsevierMultimedia ident="f0015"></elsevierMultimedia>ERT data interpretation. Defining the geoelectric boundary between clean and contaminated soilThe RES2DInv software was used for the interpretation process and an interpreted geoelectrical section was obtained for each profile. The RES2DInv software uses the smoothness-constrained least-squares method inversion technique to produce a 2D model of the subsurface. Two different variations of the smoothness constrained least-squares method are provided; one optimized for areas where the subsurface resistivity varies in a smooth manner, and another optimized for areas with sharp boundaries (<a class="elsevierStyleCrossRef" href="#bib0100">Loke and Barker, 1996</a>). The obtained geoelectrical sections have the same number of layers with same thicknesses along each profile, giving great advantage to make interpreted resistivity maps for different study depths (e.g. groundwater table depth, contamination plume, etc).<a class="elsevierStyleCrossRef" href="#f0020">Figure 4</a> shows the interpreted resistivity sections for ERT1, ERT2 and ERT3 profiles with three main layers: a superficial resistive layer consisting of sandy-clayey deposits with resistivity range from 8 to 20Ohm.m, a second layer where clay content increases with resistivity ranging from 1.5 to 9Ohm.m and a resistive third layer given by the decrease in clay content with resistivity ranging from 8 to 35Ohm.m.<elsevierMultimedia ident="f0020"></elsevierMultimedia>Taking into account the existence of high clay content in the subsoil and the characterization of mature hydrocarbon contamination as low resistivity anomaly, we need to define the geoelectric boundary between clean and contaminated soil. For this purpose, we used in the present work a conductivity model for unconsolidated formations and the “Petro-Win” software for calculation of the soil resistivity developed by Ryjov and Shevnin (<a class="elsevierStyleCrossRef" href="#bib0150">2002</a>). This model considers the geometrical microstructure of the components as well as electrochemical processes occurring in the soil for a wide range of the pore-water salinity and clay content. Once groundwater (or salinity) and soil resistivity are known, clay content and porosity are estimated for clean soil, and the geoelectric boundary is defined. The characteristics of the conductivity model, the procedure to determine the groundwater (from in-field measurements) and soil (from lab measurements) resistivity, and the equations for calculate the soil petrophysical parameters (including clay content and porosity) are explained in detail in Shevnin et al. (<a class="elsevierStyleCrossRef" href="#bib0170">2006</a>; <a class="elsevierStyleCrossRef" href="#bib0175">2007</a>) and Delgado-Rodríguez et al. (<a class="elsevierStyleCrossRef" href="#bib0040">2012</a>).In order to define the geoelectric boundary, four wells located far enough from the spill point (<a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>) were drilled in the residential zone under construction using a Geoprobe System (<a class="elsevierStyleCrossRef" href="#f0025">Figure 5</a>). Four soil samples (one per <a name="p189"></a>well) were collected from the layer noticeably more argillaceous, at depths of 6 to 7m (second layer, <a class="elsevierStyleCrossRef" href="#f0020">Figure 4</a>) and then analyzed in the laboratory, resulting in a clay content range between 37% and 50% (<a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>). Likewise, groundwater samples were collected from local aquifer, resulting in a mean resistivity values of 5.9Ohm.m at 20°C, which means a salinity of 1 g/l.<elsevierMultimedia ident="f0025"></elsevierMultimedia><elsevierMultimedia ident="tbl0005"></elsevierMultimedia>In <a class="elsevierStyleCrossRef" href="#f0030">Figure 6</a> the results of theoretical calculations with the “Petro-Win” software are shown. Soil resistivity is considered as a function of water salinity (NaCl content at 20°C). Soil resistivity curves for different sand and clay proportions are displayed: curve for sand (in the upper part of <a class="elsevierStyleCrossRef" href="#f0015">Figure 3A</a>, 0% clay, and 25% porosity) and curve for pure clay (in the lower part of <a class="elsevierStyleCrossRef" href="#f0015">Figure 3A</a>, 100% clay, and 55% porosity). Water curve (dashed curve) gives us the relation between water resistivity and water salinity; while the vertical dotted line represent the groundwater salinity mean value of 1 g/l for the study area. Two horizontal dotted lines show the resistivity range 4.5Ohm.m to 6.1Ohm.m for soils with clay content between 37% -50% and pore-water salinity 1 g/l, being 4.5Ohm.m the geoelectric boundary between clean and contaminated soil. Resistivity values less than 4.5Ohm.m correspond to mature oil contaminated soils; however, low levels of hydrocarbons contamination may be present <a name="p190"></a>in soils with resistivity values within the aforementioned resistivity interval. Resistivity values greater than 6.1Ohm.m indicate that there is no mature contamination.<elsevierMultimedia ident="f0030"></elsevierMultimedia><elsevierMultimedia ident="f0035"></elsevierMultimedia>The second layer presents low resistivity zones associated with the presence of mature hydrocarbons contamination. Using the interpreted information from <a class="elsevierStyleCrossRef" href="#f0020">Figure 4</a>, the behavior of the resistivity on the second layer (local aquifer) can be mapped with high resolution. A map of interpreted resistivity for the second layer is shown in <a class="elsevierStyleCrossRef" href="#f0035">Figure 7A</a> where the dark zones may indicate the presence of mature contamination.<a name="p191"></a>EMP data interpretationThe maximum study depth with EM31-MK2 is 6m. Considering the conductive sediments of the site, the maximum study depth corresponding, in <a class="elsevierStyleCrossRef" href="#f0015">Figure 3</a> to AB/2=12 to 13m, and higher values of the occurrence frequency, the ρa range from 7.5 to 9.5Ohm.m is defined as representative of the lithological variations in the study site for study depth equal to 6m.<a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a> shows the apparent resistivity map given by the EMP method. Three main (southern, central, and northern) low resistivity anomalies (dark zones, <a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>) are observed. The southern anomalous zone includes the railroad maintenance area (<a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>) where sulfur powder can be seen dispersed on the ground surface. Due to biodegradation processes, sulfur can cause an acidic environment, which generates salts in the subsoil and the consequent low resistivity anomaly. Therefore, the existence of chemical contamination is possible due to the presence of sulfur, therefore railroad maintenance area will be considered as contaminated by sulfur. The central anomalous zone is located within a residential zone (<a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>), coinciding with the drainage system. Due to land subsidence in the Valley of Mexico, frequently the drainage system, consisting of concrete pipelines, is broken and sewage leakages occur. In this case, we observed part of the sewage emerging on the terrain surface, resulting in low resistivity anomaly. Furthermore, the VOC values in this zone are almost zero (<a class="elsevierStyleCrossRef" href="#f0010">Figure 2</a>), ensuring the absence of recent hydrocarbon contamination. Therefore, we propose that sewage is causing this low resistivity anomalies inside residential zone (<a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>). These two areas contaminated (by sulfur and sewage) should not be considered in the setting of hydrocarbon contamination plumes (see zone framed with dashed white line in <a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>).The northern anomaly zone is located in the area where a new residential zone is being built, including the spill point (black diamond, <a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>). The cause of this anomaly zone is the presence of degraded hydrocarbons (mature contamination).Zones with high apparent resistivity values indicate the absence of degraded hydrocarbon contaminants in the subsurface and the possible presence of recent hydrocarbons contamination. However, these high values are influenced by the superficial layer of subsoil. The superficial soil resistivity is determined not only by the clay content but also by its moisture, depending on the topographical elevations changes, masking the recent contaminants effect. This is why EMP method, as well as ERT, has low resolution in detecting fresh hydrocarbons contamination plumes.In general, there is a good correspondence between ERT and EMP resistivity maps (<a class="elsevierStyleCrossRef" href="#f0035">Figure 7</a>), showing possible migration routes of the contaminants in the subsurface.Integrated data map from EMP, ERT, and VOC results.High VOC values (high level of volatiles) indicate the presence fresh contamination in the subsurface. In contaminated zones (e.g. around of the spill point), where low VOC values (VOC≤1.2 ppm) such as clean soil are observed, low resistivity anomalies (ρ≤4.5Ohm.m) confirm the existence degraded contamination. Due to this, it is necessary to integrate the geoelectric (ERT and EMP) and VOC methods results in order to define and to map all contamination plumes at the site and to focus the drilling and soil/free-product sampling.To make the integral map, a grid of 5×5m for the study site was created, and values (rather the logarithm of the values) obtained by each method were interpolated. The grid size is equal to the study area, with an approximate value of 5.3 ha. At each grid point, the applied methods receive a weight according to the interval wherein their values are (<a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>).<elsevierMultimedia ident="tbl0010"></elsevierMultimedia>The parameters or variables that integrate the map are: gas concentration (VOC) in ppm, true resistivity (ERT) inOhm.m and apparent resistivity (EMP) inOhm.m. Each variable, depending on the values range, generates a weight (or degree of reliability, Xij) of the anomalous zone. The obtained values of the indirect methods (ERT and EMP) receive weights between 0 and 5, while VOC, considered as semi-indirect method, their values receive a weight range between 0 and 7 (<a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>). Based on the petrophysical modeling performed in clean soil samples (<a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>, <a class="elsevierStyleCrossRef" href="#f0030">Figure 6</a>), the ERT interval 6.1Ohm.m≤ρ<14Ohm.m gets weight 0 since it is not related to the presence of neither fresh or mature contaminant but rather is the sediments resistivity range of the site, while the other weights values are distributed as follows: 3 to 5 and 1 to 2, for low (high resolution) and high (lower resolution) resistivity anomalies, respectively. In a similar manner, based on the correspondence between apparent resistivity <a name="p192"></a>and interpreted resistivity maps (<a class="elsevierStyleCrossRef" href="#f0035">Figure 7</a>), EMP (apparent resistivity) values receive weights 1 and 2 to high resistivity anomalies and 3 to 5 to low resistivity anomalies. Taking into account the statistical distribution of the apparent resistivity values of the <a class="elsevierStyleCrossRef" href="#f0015">Figure 3</a>, the interval 7.5Ohm.m≤ρa<9.5Ohm.m receives weight 0. The index for VOC varies between 1 and 7 depending on the increase of VOC value from 20 to 179 ppm. VOC values less than 20 ppm will have weight 0 (<a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>).The Xij calculated for each method i, in each grid point j is multiplied by a coefficient MCi (MCVOC=5 for VOC, MCERT=4 for ERT and MCEMP=3 for EMP). Finally, the average of all the values resulting from the multiplication (integral parameter, IP) is calculated by the expression:<elsevierMultimedia ident="eq0005"></elsevierMultimedia>Where: IPj –integral parameter value of the grid point j.Xij –weight value calculated from field value of the method i in grid point j.MCi –multiplication coefficient for method i.Nj –Total number of methods applied in grid point j (Nj=1, 2 or 3).It should be noted that the ranges and weights in <a class="elsevierStyleCrossRef" href="#tbl0010">Table (2)</a> are valid for the site studied in the present study. New sites require a particular analysis of the obtained data, defining new ranges and assigned weights.<a class="elsevierStyleCrossRef" href="#tbl0015">Tables 3</a> and <a class="elsevierStyleCrossRef" href="#tbl0020">4</a> show the calculation procedure using <a class="elsevierStyleCrossRef" href="#eq0005">equation (1)</a> in grid portions corresponding to two small zones predominantly contaminated with fresh and mature hydrocarbons, respectively. Near to well S1, the zone with fresh contaminants shows high VOC values (<a class="elsevierStyleCrossRef" href="#tbl0015">Table 3</a>), while low resistivity and VOC values highlight in the zone with degraded contaminants located close to the spill point (<a class="elsevierStyleCrossRef" href="#tbl0020">Table 4</a>).<elsevierMultimedia ident="tbl0015"></elsevierMultimedia><elsevierMultimedia ident="tbl0020"></elsevierMultimedia>The IPj values are mapped and shown in <a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>. Three contamination plumes are observed in the integrated map.<elsevierMultimedia ident="f0040"></elsevierMultimedia>The first plume starts at the southwestern corner of the study area and extends down Main Street to the center of the site. Taking into account its connection with gas station and the high values of VOC in this plume (presence of fresh hydrocarbons), we can affirm that the gas station is an active contamination source. Four months after the completion of this work, as a result of an integrity testing of the underground storage tank, a gasoline leaking point was found and repaired in the gas station. The second plume, located in the residential zone under construction, is related with spill point, where medium and low values of VOC and low resistivity anomalies indicate the existence de mature hydrocarbon contamination. A third contaminated zone located in the central avenue is characterized by medium values of VOC and high resistivity values. This zone was related to the basement of a furniture factory, which uses solvents and white gas for painting and cleaning activities. The factory owner recognized that oil-based paints and solvents are poured directly on the soil (personal communication).<a name="p193"></a>Verifying indirect resultsSince benzene, toluene, ethylbenzene, and xylenes (BTEX) are some of the main VOC found in petroleum derivatives such as gasoline; we performed a measurement of the concentrations of each of their constituents in order to verify the anomalies. BTEX compounds are notorious due to the contamination of soil and groundwater by gasoline (<a class="elsevierStyleCrossRef" href="#bib0045">EEA, 2010</a>). Contamination typically occurs near petroleum and natural gas production sites, petrol stations, and other areas with underground or above-ground storage tanks, containing gasoline (EEA, <a class="elsevierStyleCrossRef" href="#bib0045">2010</a>). Therefore, these compounds might be good indicator of recent contamination by gasoline. Although BTEX ratio were obtained to this purpose, it is acknowledge that inferring the age of a release based on BTEX ratios alone could be a valid approach only in well constrained situations, due to the rate of change of the gasoline BTEX ratio is affected by many site-specific variables. Another reason to measure BTEX in a gasoline contamination event was to comply with the current Mexican regulation (<a class="elsevierStyleCrossRef" href="#bib0160">SEMARNAT, 2005</a>).In addition to BTEX, light oil fraction (LOF) was measured. LOF term refers to all volatile compounds which cover the range of carbon atoms from C5 to C10. The measurement of this fraction was performed to complement the measurement of all volatile compounds that may be present on the site, complying with current Mexican regulation on soil contamination.Soil LOF AnalysisUsing the integrated map (<a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>), the drilling activities were conducted to the specific contaminated areas. Using a Geoprobe System (<a class="elsevierStyleCrossRef" href="#f0025">Figure 5</a>), six monitoring wells were drilled up to 10m of depth in strategic and topographic relevant points, taking into account the urban infrastructure and the access level to each point. Twenty two soil samples (<a class="elsevierStyleCrossRef" href="#tbl0025">Table 5</a>) were collected in monitoring wells S1-S5 and Sx, (<a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>). The analytical results revealed an irregular distribution of LOF depending on the depth ranges from bellow the detection limit to 11312mg/kg. The maximal concentration (11312mg/kg) of the site was detected in S4 in the interval of depth 3 to 4m. In well S1, a concentration value of 1338mg/kg was determinate for interval of depth 9.5 to 10m, corresponding to the GWT depth in the southern end of the site. Other noticeable concentration <a name="p194"></a>value (834mg/kg) was determinate in well S2 (<a class="elsevierStyleCrossRef" href="#tbl0025">Table 5</a>). On the other hand, the well Sx shows significant value (2071mg/kg) of LOF in sample of soil collected near to ground surface (depth~1.2m), as evidence of contamination by hydrocarbons poured on the terrain. LOF was very low in wells S3 and S5 (<a class="elsevierStyleCrossRef" href="#tbl0025">Table 5</a>).<elsevierMultimedia ident="tbl0025"></elsevierMultimedia>BTEX analysis in FP samplesOne of the age-dating methods uses benzene plus toluene to ethylbenzene plus xylenes ratios (B+T/E+X). Use of this ratio minimizes uncertainties related to historical variations in BTEX composition of manufactured gasoline and provides a valuable tool for monitoring environmental changes in a dissolved gasoline plume with time (Stout et al., <a class="elsevierStyleCrossRef" href="#bib0185">2002</a>). Although the rate of change of the gasoline BTEX ratio is affected by many site-specific variables, inferring the age of a release based on BTEX ratios alone could be a valid approach only in well constrained situations.The samples of free product FP1 and FP2 collected in well S1 and recollection trench, respectively (<a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>), did not present significant changes in the B+T/E+X ratio (<a class="elsevierStyleCrossRef" href="#f0045">Figure 9</a>). Observations revealed that fuels collected in monitoring S1 were freshly released products by continuous leaking, as noted above. This could confirm that the free product fluid rapidly migrated to the GWT. Further work is needed to analyse if chemical substantial alteration occurred during its vertical migration into the soil or it may have remained in a relatively unaltered state.<elsevierMultimedia ident="f0045"></elsevierMultimedia>BTEX ratio of free-phase gasoline sample FP3, collected in the spill point (<a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>) reached a value of 0.32, as shown in <a class="elsevierStyleCrossRef" href="#f0045">Figure 9</a>. The significant decrease of BTEX ratio on free-phase in sample FP3 implies a weathering by solubilisation, water washing or biodegradation process. Weathering and BTEX ratios imply that gasoline was transported to the water table and did not undergo substantial alteration during its vertical migration in the soil. Hence, a thin layer of free product was carried through sand lenses to the impermeable clay stratum. Therefore, when advanced alteration of the pattern has occurred due to environmental exposure, it is difficult to estimate, by composition of the free-phase, when the fuel was released. Lead and lead alkyls were absent in the free-phase sample, and is worth noting that regular unleaded gasoline was introduced in 1992.Based on the results obtained from integral map (<a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>) and BTEX analysis of FP samples (<a class="elsevierStyleCrossRef" href="#f0045">Figure 9</a>), three contaminated plumes are characterized and showed in <a class="elsevierStyleCrossRef" href="#f0050">Figure 10</a>.<elsevierMultimedia ident="f0050"></elsevierMultimedia>Plume I. “Recent Infiltration Zone”, corresponds to the most recent leakage of regular unleaded gasoline. The characteristics of the weathering processes (evaporation and solubilization) are not significant in the soil and FP samples. The contaminated plume I area is 1280m2, with a thickness according on sand layer thickness.Plume II. Defined as “soil confined gasoline zone”. It was contaminated by regular unleaded gasoline released within the last one to five years, based on the BTEX ratio analysis in FP samples. It showed a weathering process including evaporation, solubilisation, and biodegradation for a long time in a low permeability soil layer. Hydrogeology field analysis identified sand lenses confined in low permeability soil layers, the released gasoline could be trapped in a confined sand lens for years. However, site assessment work did not provide hydrogeochemical information from which reliable estimations about spill age could <a name="p195"></a><a name="p196"></a>be drawn based on the BTEX ratios. The plume II area is 1152m2, with a volume according to sand lens thickness (~0.5m).Plume III. Zone characterized by a type of hydrocarbon different to the regular gasoline founded in plumes I and II. The composition of gasoline found in the shallower part of the subsurface (depth~1.2m) was similar to “white gas”. Because of the chemical composition, weathering characteristics, contaminant transport, and hydrocarbons concentration in soils along the monitoring well Sx, plume III was considered an isolated event, not related with the other two plumes, covering a 160m2 area.The sum of the areas of each contamination plumes is 2592m2, which almost represent 5% of the study area (5.3 ha), demonstrating the benefit of using indirect methods for the optimized selection of drilling points and soil sampling depths.ConclusionsThe indirect (ERT, EMP and VOC) methods are efficient tools for studying the hydrocarbons contaminated sites, reducing the number of drilling and soil samples. The high values of VOC mapped the presence of fresh gasoline in the subsoil and suggested that the gas station located at the study site is an active contamination source. Later, from an integrity testing, a gasoline leaking point was found in the underground storage tank of the gas station. However, the considerable degradation of the regular gasoline founded in the surrounding construction area indicates, at least, the existence of a previous contamination event.The gas station is topographically located at an up gradient from the spill present in the nearby apartment construction. Therefore, gasoline released from buried pipeline would migrate toward the apartment construction area. Mature contaminated zones were defined by ERT and EMP methods as low resistivity anomalies. The ERT, EMP and VOC results were integrated on a map, allowing the final configuration of contamination plumes and the optimization of drilling and soil/free-product sampling.The affected area by hydrocarbons can be separated in three plumes with different type of contaminants: Plume I, with recent release of regular gasoline, which is connected with the gas station as active contamination source; Plume II corresponds, according to geoelectrical and BTEX analysis results, to mature (weathering and biodegradation) hydrocarbons contamination due to regular unleaded gasoline released within the last one to five years; and a small Plume III, not related with the other two plumes mentioned above, caused by pouring of solvents and white gas on soil.This study shows the advantages of joint application of ERT, EMP and VOC methods in sites with an active contamination source, where the existence of recent and mature contaminants in subsoil is suspected.<a name="p197"></a>" "textoCompletoSecciones" => array:1 [ "secciones" => array:11 [ 0 => array:3 [ "identificador" => "xres498006" "titulo" => "Resumen" "secciones" => array:1 [ 0 => array:1 [ "identificador" => "abst0005" ] ] ] 1 => array:2 [ "identificador" => "xpalclavsec519553" "titulo" => "Palabras claves" ] 2 => array:3 [ "identificador" => "xres498005" "titulo" => "Abstract" "secciones" => array:1 [ 0 => array:1 [ "identificador" => "abst0010" ] ] ] 3 => array:2 [ "identificador" => "xpalclavsec519552" "titulo" => "Keywords" ] 4 => array:2 [ "identificador" => "sec0005" "titulo" => "Introduction" ] 5 => array:2 [ "identificador" => "sec0010" "titulo" => "Site background" ] 6 => array:3 [ "identificador" => "sec0015" "titulo" => "Application of geoelectrical and VOC methods: configuration of the contamination plume" "secciones" => array:3 [ 0 => array:2 [ "identificador" => "sec0020" "titulo" => "Application of VOC measurements" ] 1 => array:2 [ "identificador" => "sec0025" "titulo" => "Application of ERT method" ] 2 => array:2 [ "identificador" => "sec0030" "titulo" => "Application of EMP method" ] ] ] 7 => array:3 [ "identificador" => "sec0035" "titulo" => "Results and discussion" "secciones" => array:5 [ 0 => array:2 [ "identificador" => "sec0040" "titulo" => "VOC data interpretation" ] 1 => array:2 [ "identificador" => "sec0045" "titulo" => "Statistical analysis of ERT data" ] 2 => array:2 [ "identificador" => "sec0050" "titulo" => "ERT data interpretation. Defining the geoelectric boundary between clean and contaminated soil" ] 3 => array:2 [ "identificador" => "sec0055" "titulo" => "EMP data interpretation" ] 4 => array:2 [ "identificador" => "sec0060" "titulo" => "Integrated data map from EMP, ERT, and VOC results." ] ] ] 8 => array:3 [ "identificador" => "sec0065" "titulo" => "Verifying indirect results" "secciones" => array:2 [ 0 => array:2 [ "identificador" => "sec0070" "titulo" => "Soil LOF Analysis" ] 1 => array:2 [ "identificador" => "sec0075" "titulo" => "BTEX analysis in FP samples" ] ] ] 9 => array:2 [ "identificador" => "sec0080" "titulo" => "Conclusions" ] 10 => array:1 [ "titulo" => "Bibliography" ] ] ] "pdfFichero" => "main.pdf" "tienePdf" => true "fechaRecibido" => "2013-03-06" "fechaAceptado" => "2013-09-03" "PalabrasClave" => array:2 [ "es" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Palabras claves" "identificador" => "xpalclavsec519553" "palabras" => array:9 [ 0 => "Benceno" 1 => "Tolueno" 2 => "Etilbenceno" 3 => "Xilenos (BTEX)" 4 => "compuestos orgánicos volátiles (COV)" 5 => "contaminación por hidrocarburos" 6 => "fuga de gasolina" 7 => "tomografía de resistividad eléctrica (TRE)" 8 => "perfilaje electromagnético (PEM)" ] ] ] "en" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Keywords" "identificador" => "xpalclavsec519552" "palabras" => array:9 [ 0 => "Benzene" 1 => "Toluene" 2 => "Ethylbenzene" 3 => "Xylenes (BTEX)" 4 => "hydrocarbons contamination" 5 => "volatile organic compounds (VOC)" 6 => "gasoline spill" 7 => "electrical resistivity tomography (ERT)" 8 => "electromagnetic profiling (EMP)" ] ] ] ] "tieneResumen" => true "resumen" => array:2 [ "es" => array:2 [ "titulo" => "Resumen" "resumen" => "Debido a la ocurrencia de un derrame de gasolina en un área urbana, los métodos de Tomografía de Resistividad Eléctrica (TRE), Perfilaje Electromagnético (PEM) y de medición de Compuestos Orgánicos Volátiles (COV) fueron utilizados para definir la pluma de contaminación y dirigir los trabajos de muestreo de suelo. Las anomalías COV (contaminación reciente) indicaron que una gasolinera localizada en el área de estudio es una fuente de contaminación activa. Las zonas con contaminación madura definidas con los métodos TRE y PEM correspondieron con anomalías de baja resistividad debido a los procesos de degradación de los hidrocarburos contaminantes. Los resultados alcanzados con los métodos TRE, PEM y VOC fueron integrados en un mapa, permitiendo la configuración final de las plumas de contaminación y la optimización de las perforaciones y el muestreo de suelo y producto libre. Análisis de laboratorio de las muestras de producto libre sugieren la existencia de más de un evento de contaminación en el sitio, con la presencia de contaminantes hidrocarburos frescos y degradados, clasificados en el rango de gasolina. Este estudio demuestra las ventajas de la aplicación conjunta de TRE, PEM y COV en sitios con fuentes de contaminación activa, donde se asume la existencia de hidrocarburos contaminantes recientes y maduros en el subsuelo." ] "en" => array:2 [ "titulo" => "Abstract" "resumen" => "As a result of a gasoline spill in an urban area, Electrical Resistivity Tomography (ERT), Electromagnetic Profiling (EMP) and Volatile Organic Compounds (VOC) methods were used in order to define the contamination plume and to optimize the drilling and soil sampling activities. The VOC anomalies (recent contamination) indicated that a gas station located at the study site is an active contamination source. The mature contaminated zones defined by ERT and EMP methods corresponded with low resistivity anomalies due to degradation process of the hydrocarbons contaminants. The ERT, EMP and VOC results were integrated on a map, allowing the final configuration of contamination plumes and the optimization of drilling and soil/free-product sampling. Laboratory analyses of free-product samples suggest the existence of more than one contamination event in the site, with the presence of recent and degraded-hydrocarbon contaminants classified in the gasoline range. This study shows the advantages of joint application of ERT, EMP and VOC methods in sites with active contamination source, where the existence of recent and mature contaminants in subsoil is assumed." ] ] "multimedia" => array:16 [ 0 => array:7 [ "identificador" => "f0005" "etiqueta" => "Figure 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1358 "Ancho" => 1310 "Tamanyo" => 151869 ] ] "descripcion" => array:1 [ "es" => "Scheme of the site." ] ] 1 => array:7 [ "identificador" => "f0010" "etiqueta" => "Figure 2" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr2.jpeg" "Alto" => 1265 "Ancho" => 1330 "Tamanyo" => 148575 ] ] "descripcion" => array:1 [ "es" => "VOC map. The dark zones indicate the presence of recent hydrocarbon contamination." ] ] 2 => array:7 [ "identificador" => "f0015" "etiqueta" => "Figure 3" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr3.jpeg" "Alto" => 1341 "Ancho" => 1355 "Tamanyo" => 128426 ] ] "descripcion" => array:1 [ "es" => "Statistical distribution of ERT data. (H) Mean resistivity curve for the study site. (C) Cloud of low apparent resistivity values separated from mean curve." ] ] 3 => array:7 [ "identificador" => "f0020" "etiqueta" => "Figure 4" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr4.jpeg" "Alto" => 1007 "Ancho" => 1469 "Tamanyo" => 110105 ] ] "descripcion" => array:1 [ "es" => "Interpreted resistivity section from ERT profiles with three layers. Low resistivity anomalies in the second layer indicate the presence of mature contamination." ] ] 4 => array:7 [ "identificador" => "f0025" "etiqueta" => "Figure 5" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr5.jpeg" "Alto" => 610 "Ancho" => 1236 "Tamanyo" => 134643 ] ] "descripcion" => array:1 [ "es" => "Geoprobe System used to collect soil and ground-water samples" ] ] 5 => array:7 [ "identificador" => "f0030" "etiqueta" => "Figure 6" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr6.jpeg" "Alto" => 1197 "Ancho" => 1248 "Tamanyo" => 139623 ] ] "descripcion" => array:1 [ "es" => "Experimental results and theoretical dependence of soil resistivity versus pore water salinity for different clay content in soils. Theoretical model: clay porosity=55%, sand porosity=25%." ] ] 6 => array:7 [ "identificador" => "f0035" "etiqueta" => "Figure 7" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr7.jpeg" "Alto" => 1592 "Ancho" => 1550 "Tamanyo" => 211582 ] ] "descripcion" => array:1 [ "es" => "Resistivity maps. Interpreted resistivity map from ERT for depth=6m. (B) Apparent resistivity map from EMP." ] ] 7 => array:7 [ "identificador" => "f0040" "etiqueta" => "Figure 8" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr8.jpeg" "Alto" => 1346 "Ancho" => 1480 "Tamanyo" => 181205 ] ] "descripcion" => array:1 [ "es" => "Integrated data map from indirect methods." ] ] 8 => array:7 [ "identificador" => "f0045" "etiqueta" => "Figure 9" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr9.jpeg" "Alto" => 854 "Ancho" => 1221 "Tamanyo" => 74157 ] ] "descripcion" => array:1 [ "es" => "BTEX ratio of free-phase gasoline samples." ] ] 9 => array:7 [ "identificador" => "f0050" "etiqueta" => "Figure 10" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr10.jpeg" "Alto" => 1001 "Ancho" => 1263 "Tamanyo" => 143388 ] ] "descripcion" => array:1 [ "es" => "Map of hydrocarbons contamination plumes." ] ] 10 => array:7 [ "identificador" => "tbl0005" "etiqueta" => "Table 1" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "tabla" => array:1 [ "tablatextoimagen" => array:1 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Clean soil sample \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Clay content (%) \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Sampling depth (m) \t\t\t\t\t\t\n \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">49 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6.6 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">38 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6.3 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">50 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6.0 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">4 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">37 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">7.0 \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab795076.png" ] ] ] ] "descripcion" => array:1 [ "es" => "Clay content and sampling depth values of the clean soil samples. Clay content values were used to define the geoelectric boundary between clean and contaminated soils." ] ] 11 => array:7 [ "identificador" => "tbl0010" "etiqueta" => "Table 2" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "tabla" => array:1 [ "tablatextoimagen" => array:1 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head " colspan="2" align="center" valign="top" scope="col" style="border-bottom: 2px solid black">EMP</th><th class="td" title="table-head " colspan="2" align="center" valign="top" scope="col" style="border-bottom: 2px solid black">ERT</th><th class="td" title="table-head " colspan="2" align="center" valign="top" scope="col" style="border-bottom: 2px solid black">VOC</th></tr><tr title="table-row"><th class="td" title="table-head " align="center" valign="top" scope="col">ρ interval (Ohm.m) \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col">Weight (XERT) \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col">ρ interval (Ohm.m) \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col">Weight (XEMP) \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col">VOC interval (ppm) \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col">Weight (XVOC) \t\t\t\t\t\t\n \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">ρa<4.3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">ρ<3.2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">VOC<20 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">4.3≤ ρa<5.9 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3.2≤ρ<4.5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">20≤VOC<28 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">5.9≤ρa<7.5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.5≤ρ<6.1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">28≤VOC<37 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">2 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">7.5≤ρa<9.5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6.1≤ρ<14.0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">37≤VOC<49 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">9.5≤ρa<13.0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">14.0≤ρ<19.0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">49≤VOC<67 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">ρa≥13.0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">ρ≥19.0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">67≤VOC<90 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">5 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">90≤VOC<120 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">VOC≥120 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">7 \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab795077.png" ] ] ] ] "descripcion" => array:1 [ "es" => "Weight assigned to each value range obtained from application of the EMP, ERT and VOC methods." ] ] 12 => array:7 [ "identificador" => "tbl0015" "etiqueta" => "Table 3" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "tabla" => array:1 [ "tablatextoimagen" => array:1 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Y \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">EMP data \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">ERT data \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">VOC data \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">XEMP* MCEMP \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">XERT * MCERT \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">XVOC* MCVOC \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">N \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">IP \t\t\t\t\t\t\n \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">580 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">190 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">12.0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">7.1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">--- \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1.5 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">580 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">195 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">10.2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">7.2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1.8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1.0 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">580 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">200 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">8.6 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">7.1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">98.9 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">30 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">10.0 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">580 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">205 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">7.6 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.4 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">170.0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">35 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">14.3 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">580 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">210 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">7.6 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">2.8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">26.8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">16 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">7.0 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">580 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">215 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">7.5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">--- \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">9 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.0 \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab795075.png" ] ] ] ] "descripcion" => array:1 [ "es" => "Calculation of IP in a portion of the grid around the well S1, where the recent contamination is mainly characterized by high VOC values." ] ] 13 => array:7 [ "identificador" => "tbl0020" "etiqueta" => "Table 4" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "tabla" => array:1 [ "tablatextoimagen" => array:1 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Y \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">EMP data \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">ERT data \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">VOC data \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">XEMP* MCEMP \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">XERT * MCERT \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">XVOC* MCVOC \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">N \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">IP \t\t\t\t\t\t\n \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">640 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">250 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">8.1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">--- \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0.5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0.0 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">640 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">255 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">8.1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6.1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0.7 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">12 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.0 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">640 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">260 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">8.1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0.9 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">16 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">5.3 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">640 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">265 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">8.1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3.2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1.0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">20 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6.7 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">640 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">270 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">8.2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3.3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1.2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">20 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6.7 \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="center" valign="top">640 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">275 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">8.2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1.1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">16 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">5.3 \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab795078.png" ] ] ] ] "descripcion" => array:1 [ "es" => "Calculation of IP in a portion of the grid around the spill point, where mature contamination is characterized by low resistivity and VOC values." ] ] 14 => array:7 [ "identificador" => "tbl0025" "etiqueta" => "Table 5" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "tabla" => array:1 [ "tablatextoimagen" => array:1 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head " align="left" valign="top" scope="col" style="border-bottom: 2px solid black">Well \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Y \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">LOF (ppm) \t\t\t\t\t\t\n \t\t\t\t</th><th class="td" title="table-head " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Sampling Depth \t\t\t\t\t\t\n \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td" title="table-entry " align="left" valign="top">S1 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">589 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">208 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">678 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">5.50 - 6.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1338 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">9.50 - 10.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">50 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0.0 - 2.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">834 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">2.00 - 3.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">306 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3.00 - 4.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="left" valign="top">S2 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">620 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">267 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">141 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.00 - 5.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">62 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">5.20 - 5.80 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">65 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6.00 - 6.30 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">BDL \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6.80 - 7.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="left" valign="top">S3 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">654 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">281 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">50 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">0.0 - 3.80 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">51 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">6.00 - 7.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">38 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">1.50 a 1.90 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">BDL \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">2.00 - 3.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="left" valign="top">S4 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">621 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">245 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">11312 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3.00 - 4.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">330 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.00 - 5.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">86 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">5.00 - 6.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">44 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3.00 - 4.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="left" valign="top">S5 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">630.9 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">253.8 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">55 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.00 - 5.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">33 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">5.00 - 6.80 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">2071 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">3.15 - 4.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="left" valign="top">Sx \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">616 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">294 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">301 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.00 - 4.40 m \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="" valign="top"> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">279 \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="table-entry " align="center" valign="top">4.40 - 5.00 m \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab795074.png" ] ] ] ] "descripcion" => array:1 [ "es" => "Soil LOF concentration and sampling depth values. Grey rows show the maximal LOF concentrations for each well." ] ] 15 => array:6 [ "identificador" => "eq0005" "etiqueta" => "(1)" "tipo" => "MULTIMEDIAFORMULA" "mostrarFloat" => false "mostrarDisplay" => true "Formula" => array:5 [ "Matematica" => "IPj=∑i=1Nj(Xij*MCi)" "Fichero" => "si1.jpeg" "Tamanyo" => 1633 "Alto" => 21 "Ancho" => 160 ] ] ] "bibliografia" => array:2 [ "titulo" => "Bibliography" "seccion" => array:1 [ 0 => array:2 [ "identificador" => "bibs0005" "bibliografiaReferencia" => array:38 [ 0 => array:3 [ "identificador" => "bib0005" "etiqueta" => "Abdel Aal et al., 2004" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Effects of microbial processes on electrolytic and interfacial electrical properties of unconsolidated sediments" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "G.Z. Abdel Aal" 1 => "E. Atekwana" 2 => "L.D. Slater" 3 => "E.A. Atekwana" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Geophys. Res. Lett" "fecha" => "2004" "volumen" => "31" "numero" => "12" "paginaInicial" => "1" "paginaFinal" => "4" ] ] ] ] ] ] 1 => array:3 [ "identificador" => "bib0010" "etiqueta" => "API, 1991" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "An evaluation of soil gas and geophysical techniques for detection of hydrocarbons" "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "API" "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:4 [ "titulo" => "API Publication Nº 4509, Washington, D.C." "fecha" => "1991" "editorial" => "Health and Environmental Sciences Department, American Petroleum Institute" "editorialLocalizacion" => "USA" ] ] ] ] ] ] 2 => array:3 [ "identificador" => "bib0015" "etiqueta" => "Arpel, 1992" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Regional association of oil, gas and biofuels sector companies in Latin America and the Caribbean" "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "Arpel" "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "fecha" => "1992" "editorial" => "Guide to solid waste management oil refinery" "editorialLocalizacion" => "Canada" ] ] ] ] ] ] 3 => array:3 [ "identificador" => "bib0020" "etiqueta" => "Atekwana et al., 2001" "referencia" => array:1 [ 0 => array:1 [ "referenciaCompleta" => "Atekwana E., Cassidy D.P., Magnuson C. Endres, Werkema A.L., D.D. Jr., Sauck W.A., 2001, Changes in geoelectrical properties accompanying microbial degradation of LNAPL. In Proceedings of the Symposium on the Application of Geophysics to Engineering and Environmental Problems, Denver, Colorado, USA." ] ] ] 4 => array:3 [ "identificador" => "bib0025" "etiqueta" => "Briggs, 1974" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Machine contouring using minimum curvature" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "I.C. Briggs" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Geophysics" "fecha" => "1974" "volumen" => "39" "paginaInicial" => "39" "paginaFinal" => "48" ] ] ] ] ] ] 5 => array:3 [ "identificador" => "bib0030" "etiqueta" => "Delgado-Rodríguez et al., 2006" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Geoelectrical characterization of a site with hydrocarbon contamination caused by pipeline leakage" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "O. Delgado-Rodríguez" 1 => "V. Shevnin" 2 => "J. OchoaValdés" 3 => "A. Ryjov" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Geofísica Internacional" "fecha" => "2006" "volumen" => "45" "numero" => "1" "paginaInicial" => "63" "paginaFinal" => "72" ] ] ] ] ] ] 6 => array:3 [ "identificador" => "bib0035" "etiqueta" => "Delgado-Rodríguez et al., 2006a" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Using electrical techniques for planning the remediation process in a hydrocarbon contaminated site" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "O. Delgado-Rodríguez" 1 => "V. Shevnin" 2 => "J. OchoaValdés" 3 => "A. Ryjov" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Rev. Int. Contam. Ambient" "fecha" => "2006" "volumen" => "22" "numero" => "4" "paginaInicial" => "157" "paginaFinal" => "163" ] ] ] ] ] ] 7 => array:3 [ "identificador" => "bib0040" "etiqueta" => "Delgado-Rodríguez et al., 2012" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Estimation of soil petrophysical parameters based on electrical resistivity values obtained from lab and in-field measurements" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "O. Delgado-Rodríguez" 1 => "M. Ladrón de GuevaraTorres" 2 => "V. Shevnin" 3 => "A. Ryjov" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Geofísica Internacional" "fecha" => "2012" "volumen" => "51" "numero" => "1" "paginaInicial" => "5" "paginaFinal" => "15" ] ] ] ] ] ] 8 => array:3 [ "identificador" => "bib0045" "etiqueta" => "EEA, 2010" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:1 [ "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "EEA" "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:2 [ "titulo" => "Benzene, toluene, ethylbenzene, xylene (as BTEX): European Environment Agency" "fecha" => "2010" ] ] ] ] ] ] 9 => array:3 [ "identificador" => "bib0050" "etiqueta" => "Fischer et al., 1996" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Factors affecting indoor air concentrations of volatile organic compounds at a site of subsurface gasoline contamination" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:6 [ 0 => "M. Fischer" 1 => "A. Bentley" 2 => "K. Dunkin" 3 => "A. Hodgson" 4 => "W. Nazaroff" 5 => "J.D. Sextro" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Environ. Sci. Technol" "fecha" => "1996" "volumen" => "30" "paginaInicial" => "2948" "paginaFinal" => "2957" ] ] ] ] ] ] 10 => array:3 [ "identificador" => "bib0055" "etiqueta" => "Geonics Limited, 2010" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:1 [ "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "Geonics Limited" "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "titulo" => "EM31-MK2, Operating Manual" "fecha" => "2010" "paginaInicial" => "51" ] ] ] ] ] ] 11 => array:3 [ "identificador" => "bib0060" "etiqueta" => "Golden Software Inc., 2002" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Surfer. User´s Guide" "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "Golden Software Inc." "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "titulo" => "Contouring and 3D mapping for Scientists and Engineers" "fecha" => "2002" "paginaInicial" => "640" ] ] ] ] ] ] 12 => array:3 [ "identificador" => "bib0065" "etiqueta" => "IMP, 2006" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Proyecto F.21320 “Caracterización de la contaminación de suelos y agua freática en once diferentes sitios del D.D.V. Minatitlán – Villahermosa y D.D.V. Minatitlán – México”" "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "IMP" "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "titulo" => "Dirección de Seguridad y Medio Ambiente" "fecha" => "2006" "editorial" => "Instituto Mexicano del Petróleo" ] ] ] ] ] ] 13 => array:3 [ "identificador" => "bib0070" "etiqueta" => "IMP, 2006a" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Proyecto F.21399 “Apoyo para la caracterización y restauración del área norte de la ex - Refinería 18 de Marzo”" "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "IMP" "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "titulo" => "Dirección de Seguridad y Medio Ambiente" "fecha" => "2006" "editorial" => "Instituto Mexicano del Petróleo" ] ] ] ] ] ] 14 => array:3 [ "identificador" => "bib0075" "etiqueta" => "IMP, 2008" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Proyecto F.21472 “Evaluación del estado actual de la contaminación por hidrocarburos en el suelo y agua subterránea de la TAD de Azcapotzalco”" "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "IMP" "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "titulo" => "Dirección de Seguridad y Medio Ambiente" "fecha" => "2008" "editorial" => "Instituto Mexicano del Petróleo" ] ] ] ] ] ] 15 => array:3 [ "identificador" => "bib0080" "etiqueta" => "IMP, 2013" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Proyecto F.23487 “Estudio de la contaminación por hidrocarburos en suelo y subsuelo del área de reconfiguración (CADI) de la Refinería Ing. Antonio M. Amor de Salamanca, Gto.”" "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "IMP" "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:2 [ "titulo" => "Dirección de Seguridad y Medio Ambiente, Instituto Mexicano del Petróleo" "fecha" => "2013" ] ] ] ] ] ] 16 => array:3 [ "identificador" => "bib0085" "etiqueta" => "Keller and Frischknecht, 1966" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:1 [ "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "G.V. Keller" 1 => "F.C. Frischknecht" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:5 [ "titulo" => "Electrical methods in geophysical prospecting" "fecha" => "1966" "paginaInicial" => "517" "editorial" => "Pergamon Press" "editorialLocalizacion" => "Oxford" ] ] ] ] ] ] 17 => array:3 [ "identificador" => "bib0090" "etiqueta" => "Korhonen et al., 2005" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Interpretation of lineaments from airborne geophysical and topographic data. An alternative model within version Laxemar 1.2 of the Oskarshamn modelling project" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "K. Korhonen" 1 => "A. Kuivamäki" 2 => "T. Ruotoistenmäki" 3 => "M. Paananen" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "titulo" => "Geological Survey of Finland" "fecha" => "2005" "paginaInicial" => "39" ] ] ] ] ] ] 18 => array:3 [ "identificador" => "bib0095" "etiqueta" => "Lin and Chou, 2006" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Henry’s law constant variations of volatile organic compounds in wastewater and activated sludge" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "J.H. Lin" 1 => "M.S. Chou" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Aerosol and Air Quality Research" "fecha" => "2006" "volumen" => "6" "numero" => "2" "paginaInicial" => "180" "paginaFinal" => "192" ] ] ] ] ] ] 19 => array:3 [ "identificador" => "bib0100" "etiqueta" => "Loke and Barker, 1996" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Rapid least-squares inversion of apparent resistivity pseudosections by a quasi-Newton method" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "M.H. Loke" 1 => "R.D. Barker" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Geophys. Prospect" "fecha" => "1996" "volumen" => "44" "paginaInicial" => "131" "paginaFinal" => "152" ] ] ] ] ] ] 20 => array:3 [ "identificador" => "bib0105" "etiqueta" => "Loke, 2013" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:1 [ "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "M.H. Loke" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "titulo" => "Tutorial: 2-D and 3-D electrical imaging surveys" "fecha" => "2013" "paginaInicial" => "162" ] ] ] ] ] ] 21 => array:3 [ "identificador" => "bib0110" "etiqueta" => "Marín-Córdova et al., 1986" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:1 [ "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "S. Marín-Córdova" 1 => "C.J. Aguayo" 2 => "A.R. Huízar" 3 => "V.J. Mandujano" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:4 [ "titulo" => "Geología en el Valle de México con fines geohidrológicos" "fecha" => "1986" "editorial" => "Instituto de Geología" "editorialLocalizacion" => "UNAM y CAVM" ] ] ] ] ] ] 22 => array:3 [ "identificador" => "bib0115" "etiqueta" => "Méndez-Velarde et al., 2012" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Diseño de un plan de muestreo optimizado para la caracterización de hidrocarburos en suelos" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "S.F. Méndez-Velarde" 1 => "J. Ochoa-Valdés" 2 => "O. Delgado-Rodríguez" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:4 [ "titulo" => "Caso de estudio (48.6 hectáreas). SMA5, XVIII Foro de Avances de la Industria de la Refinación" "fecha" => "2012" "editorial" => "Instituto Mexicano del Petróleo" "editorialLocalizacion" => "México DF" ] ] ] ] ] ] 23 => array:3 [ "identificador" => "bib0120" "etiqueta" => "Modin et al., 1997" "referencia" => array:1 [ 0 => array:1 [ "referenciaCompleta" => "Modin I.N., Shevnin V.A., Bobatchev A.A., Bolshakov D.K. Leonov D.A., Vladov M.L., 1997, Investigations of oil pollution with electrical prospecting methods. In: Proceedings of the 3rd EEGS-ES Meeting, Aarhus, Denmark, 267-270." ] ] ] 24 => array:3 [ "identificador" => "bib0125" "etiqueta" => "Ochoa et al., 2007" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Aplicación del análisis de vapores orgánicos del subsuelo (gasometrías) en la caracterización de sitios contaminados por hidrocarburos" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "J. Ochoa" 1 => "S. Méndez" 2 => "C. Valdés" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:2 [ "titulo" => "Derecho de Autor No. 03-2007-061912264100-01, Instituto Mexicano del Petróleo" "fecha" => "2007" ] ] ] ] ] ] 25 => array:3 [ "identificador" => "bib0130" "etiqueta" => "Ochoa et al., 2002" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Evaluación de la contaminación por hidrocarburos del subsuelo (gasometrías)" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "J. Ochoa" 1 => "S. Méndez" 2 => "A. Rosas" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "El Petróleo de México" "fecha" => "2002" "volumen" => "III" "numero" => "2" "paginaInicial" => "42" "paginaFinal" => "54" ] ] ] ] ] ] 26 => array:3 [ "identificador" => "bib0135" "etiqueta" => "Osella et al., 2002" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Characterization of a contaminant plume due to a hydrocarbon spill using geoelectrical methods" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:3 [ 0 => "A. Osella" 1 => "M. De la Vega" 2 => "E. Lascano" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "J Environ. Eng. Geophysics" "fecha" => "2002" "volumen" => "7" "paginaInicial" => "78" "paginaFinal" => "87" ] ] ] ] ] ] 27 => array:3 [ "identificador" => "bib0140" "etiqueta" => "Ontario Geological Survey, 2003" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Ontario airborne geophysical surveys, magnetic data, Oba-Kapuskasing area" "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "Ontario Geological Survey" "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "titulo" => "Geophysical Data Set 1024 – Revised" "fecha" => "2003" "paginaInicial" => "67" ] ] ] ] ] ] 28 => array:3 [ "identificador" => "bib0145" "etiqueta" => "Orfanos and Apostolopoulos, 2012" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Analysis of different geophysical methods in the detection of an underground opening at a controlled test site" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "C. Orfanos" 1 => "G. Apostolopoulos" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Journal of the Balkan Geophysical Society" "fecha" => "2012" "volumen" => "15" "numero" => "1" "paginaInicial" => "7" "paginaFinal" => "18" ] ] ] ] ] ] 29 => array:3 [ "identificador" => "bib0150" "etiqueta" => "Ryjov and Shevnin, 2002" "referencia" => array:1 [ 0 => array:1 [ "referenciaCompleta" => "Ryjov A., Shevnin V., 2002, Theoretical calculation of rocks electrical resistivity and some examples of algorithm’s application. In Proceedings of the Symposium on the Application of Geophysics to Engineering and Environmental Problems (SAGEEP), Las Vegas, Nevada, USA." ] ] ] 30 => array:3 [ "identificador" => "bib0155" "etiqueta" => "Sauck, 2000" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "A model for the resistivity structure of LNAPL plumes and their environs in sandy sediments" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "W.A. Sauck" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "J. App. Geophys" "fecha" => "2000" "volumen" => "44" "paginaInicial" => "151" "paginaFinal" => "165" ] ] ] ] ] ] 31 => array:3 [ "identificador" => "bib0160" "etiqueta" => "SEMARNAT, 2005" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Norma Oficial Mexicana NOM-138-SEMARNAT/SS-2003, Límites máximos permisibles de contaminación en suelos por hidrocarburos y las especificaciones para su caracterización y remediación" "autores" => array:1 [ 0 => array:2 [ "colaboracion" => "SEMARNAT" "etal" => false ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:2 [ "titulo" => "Diario Oficial de la Federación" "fecha" => "2005" ] ] ] ] ] ] 32 => array:3 [ "identificador" => "bib0165" "etiqueta" => "Shevnin et al., 2005" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Geoelectrical characterization of an oil contaminated site in Tabasco, Mexico" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:6 [ 0 => "V. Shevnin" 1 => "O. Delgado-Rodríguez" 2 => "L. FernándezLinares" 3 => "H. Zegarra-Martinez" 4 => "A. Mousatov" 5 => "A.A. Ryjov" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Geofísica Internacional" "fecha" => "2005" "volumen" => "44" "numero" => "3" "paginaInicial" => "251" "paginaFinal" => "263" ] ] ] ] ] ] 33 => array:3 [ "identificador" => "bib0170" "etiqueta" => "Shevnin et al., 2006" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Estimation of soil petrophysical parameters from resistivity data: Application to oil-contaminated site characterization" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:6 [ 0 => "V. Shevnin" 1 => "O. Delgado-Rodríguez" 2 => "A. Mousatov" 3 => "D. Flores-Hernández" 4 => "H. Zegarra-Martinez" 5 => "A.A. Ryjov" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:6 [ "tituloSerie" => "Geofísica Internacional" "fecha" => "2006" "volumen" => "45" "numero" => "3" "paginaInicial" => "179" "paginaFinal" => "193" ] ] ] ] ] ] 34 => array:3 [ "identificador" => "bib0175" "etiqueta" => "Shevnin et al., 2007" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Estimation of clay content in soil based on resistivity modeling and laboratory measurements" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "V. Shevnin" 1 => "A. Mousatov" 2 => "A.A. Ryjov" 3 => "O. DelgadoRodríguez" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Geophy. Prosp" "fecha" => "2007" "volumen" => "55" "paginaInicial" => "265" "paginaFinal" => "275" ] ] ] ] ] ] 35 => array:3 [ "identificador" => "bib0180" "etiqueta" => "Siemon, 2009" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Levelling of helicopter-borne frequency-domain electromagnetic data" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "B. Siemon" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Revista" => array:5 [ "tituloSerie" => "Journal of Applied Geophysics" "fecha" => "2009" "volumen" => "67" "paginaInicial" => "206" "paginaFinal" => "218" ] ] ] ] ] ] 36 => array:3 [ "identificador" => "bib0185" "etiqueta" => "Stout et al., 2002" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Chemical Fingerprinting of Hydrocarbons" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:4 [ 0 => "S.A. Stout" 1 => "A.D. Uhler" 2 => "K.J. McCarthy" 3 => "Emsbo Mattingly" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:6 [ "titulo" => "Introduction to environmental forensics" "fecha" => "2002" "paginaInicial" => "137" "paginaFinal" => "260" "editorial" => "Academic Press" "editorialLocalizacion" => "San Diego, California" ] ] ] ] ] ] 37 => array:3 [ "identificador" => "bib0190" "etiqueta" => "Vanhala, 1997" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Laboratory and field studies of environmental and exploration applications of the spectral induced-polarization (SIP) method" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "H. Vanhala" ] ] ] ] ] "host" => array:1 [ 0 => array:1 [ "Libro" => array:3 [ "titulo" => "Academic dissertation, for the degree of Doctor of Technology" "fecha" => "1997" "editorial" => "Helsinki University of Technology" ] ] ] ] ] ] ] ] ] ] ] "idiomaDefecto" => "es" "url" => "/00167169/0000005300000002/v2_201505081358/S0016716914714990/v2_201505081358/es/main.assets" "Apartado" => array:4 [ "identificador" => "36047" "tipo" => "SECCION" "es" => array:2 [ "titulo" => "Original paper" "idiomaDefecto" => true ] "idiomaDefecto" => "es" ] "PDF" => "https://static.elsevier.es/multimedia/00167169/0000005300000002/v2_201505081358/S0016716914714990/v2_201505081358/es/main.pdf?idApp=UINPBA00004N&text.app=https://www.elsevier.es/" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0016716914714990?idApp=UINPBA00004N"]

Estadísticas

Omar Delgado-Rodríguez

Autor para correspondencia

odelgado@imp.mx

Corresponding author:

, David Flores-Hernández, Myriam A. Amezcua-Allieri, Andrés Rosas-Molina, Salvador Marín-Córdova

Instituto Mexicano del Petróleo (IMP), Lázaro Cárdenas Norte 152, San Bartolo Atepehuacan, 07730 México D.F.

Vladimir Shevnin

Moscow State University Geological Faculty Department of Geophysics Leninskie Gory, 119991 Moscow, Russia.

Leído

3096

Veces
se ha leído el artículo

899

Total PDF

2197

Total HTML

Compartir estadísticas

 array:23 [
  "pii" => "S0016716914714990"
  "issn" => "00167169"
  "doi" => "10.1016/S0016-7169(14)71499-0"
  "estado" => "S300"
  "fechaPublicacion" => "2014-04-01"
  "aid" => "71499"
  "copyright" => "Universidad Nacional Aut&#243;noma de M&#233;xico"
  "copyrightAnyo" => "2014"
  "documento" => "article"
  "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/"
  "subdocumento" => "fla"
  "cita" => "Geofisica Internacional. 2014;53:183-98"
  "abierto" => array:3 [
    "ES" => true
    "ES2" => true
    "LATM" => true
  ]
  "gratuito" => true
  "lecturas" => array:2 [
    "total" => 1383
    "formatos" => array:3 [
      "EPUB" => 39
      "HTML" => 936
      "PDF" => 408
    ]
  ]
  "itemSiguiente" => array:18 [
    "pii" => "S0016716914715004"
    "issn" => "00167169"
    "doi" => "10.1016/S0016-7169(14)71500-4"
    "estado" => "S300"
    "fechaPublicacion" => "2014-04-01"
    "aid" => "71500"
    "copyright" => "Universidad Nacional Aut&#243;noma de M&#233;xico"
    "documento" => "article"
    "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/"
    "subdocumento" => "fla"
    "cita" => "Geofisica Internacional. 2014;53:199-210"
    "abierto" => array:3 [
      "ES" => true
      "ES2" => true
      "LATM" => true
    ]
    "gratuito" => true
    "lecturas" => array:2 [
      "total" => 1317
      "formatos" => array:3 [
        "EPUB" => 28
        "HTML" => 912
        "PDF" => 377
      ]
    ]
    "en" => array:11 [
      "idiomaDefecto" => true
      "titulo" => "Geological and geophysical data integration for delimitation of mineralized areas in a supergene manganese deposits"
      "tienePdf" => "en"
      "tieneTextoCompleto" => "en"
      "tieneResumen" => array:2 [
        0 => "es"
        1 => "en"
      ]
      "paginas" => array:1 [
        0 => array:2 [
          "paginaInicial" => "199"
          "paginaFinal" => "210"
        ]
      ]
      "contieneResumen" => array:2 [
        "es" => true
        "en" => true
      ]
      "contieneTextoCompleto" => array:1 [
        "en" => true
      ]
      "contienePdf" => array:1 [
        "en" => true
      ]
      "resumenGrafico" => array:2 [
        "original" => 0
        "multimedia" => array:7 [
          "identificador" => "f0005"
          "etiqueta" => "Figure 1"
          "tipo" => "MULTIMEDIAFIGURA"
          "mostrarFloat" => true
          "mostrarDisplay" => false
          "figura" => array:1 [
            0 => array:4 [
              "imagen" => "gr1.jpeg"
              "Alto" => 1140
              "Ancho" => 1181
              "Tamanyo" => 222753
            ]
          ]
          "descripcion" => array:1 [
            "en" => "<p id="sp0005" class="elsevierStyleSimplePara elsevierViewall">Location of the area of study&#44; with positioning of lines of acquisition of geophysical data in the area of mining of manganese mineral&#46;</p>"
          ]
        ]
      ]
      "autores" => array:1 [
        0 => array:2 [
          "autoresLista" => "C&#233;sar Augusto Moreira, Mario Rezende Borges, Glauber Matheus Lira Vieira, Walter Malagutti Filho, Mariana Aparecida Fern&#225;ndes Montanheiro"
          "autores" => array:5 [
            0 => array:2 [
              "nombre" => "C&#233;sar"
              "apellidos" => "Augusto Moreira"
            ]
            1 => array:2 [
              "nombre" => "Mario"
              "apellidos" => "Rezende Borges"
            ]
            2 => array:2 [
              "nombre" => "Glauber Matheus"
              "apellidos" => "Lira Vieira"
            ]
            3 => array:2 [
              "nombre" => "Walter"
              "apellidos" => "Malagutti Filho"
            ]
            4 => array:2 [
              "nombre" => "Mariana Aparecida"
              "apellidos" => "Fern&#225;ndes Montanheiro"
            ]
          ]
        ]
      ]
    ]
    "idiomaDefecto" => "en"
    "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0016716914715004?idApp=UINPBA00004N"
    "url" => "/00167169/0000005300000002/v2_201505081358/S0016716914715004/v2_201505081358/en/main.assets"
  ]
  "itemAnterior" => array:18 [
    "pii" => "S0016716914714989"
    "issn" => "00167169"
    "doi" => "10.1016/S0016-7169(14)71498-9"
    "estado" => "S300"
    "fechaPublicacion" => "2014-04-01"
    "aid" => "71498"
    "copyright" => "Universidad Nacional Aut&#243;noma de M&#233;xico"
    "documento" => "article"
    "licencia" => "http://creativecommons.org/licenses/by-nc-nd/4.0/"
    "subdocumento" => "fla"
    "cita" => "Geofisica Internacional. 2014;53:163-81"
    "abierto" => array:3 [
      "ES" => true
      "ES2" => true
      "LATM" => true
    ]
    "gratuito" => true
    "lecturas" => array:2 [
      "total" => 1298
      "formatos" => array:3 [
        "EPUB" => 25
        "HTML" => 843
        "PDF" => 430
      ]
    ]
    "en" => array:11 [
      "idiomaDefecto" => true
      "titulo" => "A multivariate Bernstein copula model for permeability stochastic simulation"
      "tienePdf" => "en"
      "tieneTextoCompleto" => "en"
      "tieneResumen" => array:2 [
        0 => "es"
        1 => "en"
      ]
      "paginas" => array:1 [
        0 => array:2 [
          "paginaInicial" => "163"
          "paginaFinal" => "181"
        ]
      ]
      "contieneResumen" => array:2 [
        "es" => true
        "en" => true
      ]
      "contieneTextoCompleto" => array:1 [
        "en" => true
      ]
      "contienePdf" => array:1 [
        "en" => true
      ]
      "resumenGrafico" => array:2 [
        "original" => 0
        "multimedia" => array:7 [
          "identificador" => "f0040"
          "etiqueta" => "Figure 8"
          "tipo" => "MULTIMEDIAFIGURA"
          "mostrarFloat" => true
          "mostrarDisplay" => false
          "figura" => array:1 [
            0 => array:4 [
              "imagen" => "gr8.jpeg"
              "Alto" => 1081
              "Ancho" => 1087
              "Tamanyo" => 130538
            ]
          ]
          "descripcion" => array:1 [
            "en" => "<p id="sp0040" class="elsevierStyleSimplePara elsevierViewall">Scatter plot and histograms of VS Meas and K &#40;Simulated values&#41;&#46;</p>"
          ]
        ]
      ]
      "autores" => array:2 [
        0 => array:2 [
          "autoresLista" => "Victor Hern&#225;ndez-Maldonado, Mart&#237;n D&#237;az-Viera"
          "autores" => array:2 [
            0 => array:2 [
              "nombre" => "Victor"
              "apellidos" => "Hern&#225;ndez-Maldonado"
            ]
            1 => array:2 [
              "nombre" => "Mart&#237;n"
              "apellidos" => "D&#237;az-Viera"
            ]
          ]
        ]
        1 => array:2 [
          "autoresLista" => "Arturo Erdely"
          "autores" => array:1 [
            0 => array:2 [
              "nombre" => "Arturo"
              "apellidos" => "Erdely"
            ]
          ]
        ]
      ]
    ]
    "idiomaDefecto" => "en"
    "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0016716914714989?idApp=UINPBA00004N"
    "url" => "/00167169/0000005300000002/v2_201505081358/S0016716914714989/v2_201505081358/en/main.assets"
  ]
  "es" => array:17 [
    "idiomaDefecto" => true
    "titulo" => "Joint interpretation of geoelectrical and volatile organic compounds data&#58; a case study in a hydrocarbons contaminated urban site"
    "tieneTextoCompleto" => true
    "paginas" => array:1 [
      0 => array:2 [
        "paginaInicial" => "183"
        "paginaFinal" => "198"
      ]
    ]
    "autores" => array:2 [
      0 => array:4 [
        "autoresLista" => "Omar Delgado-Rodr&#237;guez, David Flores-Hern&#225;ndez, Myriam A&#46; Amezcua-Allieri, Andr&#233;s Rosas-Molina, Salvador Mar&#237;n-C&#243;rdova"
        "autores" => array:5 [
          0 => array:4 [
            "nombre" => "Omar"
            "apellidos" => "Delgado-Rodr&#237;guez"
            "email" => array:1 [
              0 => "odelgado&#64;imp&#46;mx"
            ]
            "referencia" => array:1 [
              0 => array:2 [
                "etiqueta" => "<span class="elsevierStyleSup">&#42;</span>"
                "identificador" => "cor0005"
              ]
            ]
          ]
          1 => array:2 [
            "nombre" => "David"
            "apellidos" => "Flores-Hern&#225;ndez"
          ]
          2 => array:2 [
            "nombre" => "Myriam A&#46;"
            "apellidos" => "Amezcua-Allieri"
          ]
          3 => array:2 [
            "nombre" => "Andr&#233;s"
            "apellidos" => "Rosas-Molina"
          ]
          4 => array:2 [
            "nombre" => "Salvador"
            "apellidos" => "Mar&#237;n-C&#243;rdova"
          ]
        ]
        "afiliaciones" => array:1 [
          0 => array:2 [
            "entidad" => "Instituto Mexicano del Petr&#243;leo &#40;IMP&#41;&#44; L&#225;zaro C&#225;rdenas Norte 152&#44; San Bartolo Atepehuacan&#44; 07730 M&#233;xico D&#46;F&#46;"
            "identificador" => "aff0005"
          ]
        ]
        "correspondencia" => array:1 [
          0 => array:3 [
            "identificador" => "cor0005"
            "etiqueta" => "&#42;"
            "correspondencia" => "Corresponding author&#58;"
          ]
        ]
      ]
      1 => array:3 [
        "autoresLista" => "Vladimir Shevnin"
        "autores" => array:1 [
          0 => array:2 [
            "nombre" => "Vladimir"
            "apellidos" => "Shevnin"
          ]
        ]
        "afiliaciones" => array:1 [
          0 => array:2 [
            "entidad" => "Moscow State University Geological Faculty Department of Geophysics Leninskie Gory&#44; 119991 Moscow&#44; Russia&#46;"
            "identificador" => "aff0010"
          ]
        ]
      ]
    ]
    "resumenGrafico" => array:2 [
      "original" => 0
      "multimedia" => array:7 [
        "identificador" => "f0045"
        "etiqueta" => "Figure 9"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr9.jpeg"
            "Alto" => 854
            "Ancho" => 1221
            "Tamanyo" => 74157
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0045" class="elsevierStyleSimplePara elsevierViewall">BTEX ratio of free-phase gasoline samples&#46;</p>"
        ]
      ]
    ]
    "textoCompleto" => "<span class="elsevierStyleSections"><span id="sec0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0025"><a name="p184"></a>Introduction</span><p id="par0005" class="elsevierStylePara elsevierViewall">Hydrocarbons are among the main factors of geological medium contamination&#46; The effectiveness of electrical methods for the characterization&#44; on surface and depth&#44; of oil contaminated plumes has been reported by several authors &#40;<a class="elsevierStyleCrossRef" href="#bib0190">Vanhala&#44; 1997</a>&#59; Modin <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0120">1997</a>&#59; Atekwana <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0020">2001</a>&#59; Osella <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0135">2002</a>&#59; Delgado-Rodr&#237;guez <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0030">2006</a>&#59; <a class="elsevierStyleCrossRef" href="#bib0035">2006a</a>&#41;&#46; Just after contamination&#44; a high resistivity anomaly delimits the contaminated zone&#46; Oil contaminants cause changes in physical&#44; chemical and biological properties of soil &#40;<a class="elsevierStyleCrossRef" href="#bib0155">Sauck&#44; 2000</a>&#59; Atekwana <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0020">2001</a>&#41;&#44; mainly during the first four to six months after contamination&#46; Abdel-Aal <span class="elsevierStyleItalic">et al</span>&#46; &#40;<a class="elsevierStyleCrossRef" href="#bib0005">2004</a>&#41; found some important details on biodegradation process and changes in the electrical properties of contaminated zones&#46; They demonstrated that the decrease of resistivity in soil contaminated by degraded hydrocarbons is mainly related to high surface conductivity in the pores of the affected rocks&#46; Thus&#44; the low resistivity anomalies are associated to the existence of mature hydrocarbon contamination&#46; Electrical Resistivity Tomography &#40;ERT&#41; and Electromagnetic Profiling &#40;EMP&#41; are effective tools to mapping low resistivity anomalies caused by hydrocarbon contamination &#40;Shevnin <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0165">2005</a>&#41;&#46;</p><p id="par0010" class="elsevierStylePara elsevierViewall">ERT is applied in order to obtain a geoelectrical image of the sub-surface using electrical measurements made along profile at the surface&#46; The application of ERT method is based on apparent resistivity determination with the help of linear array &#40;e&#46;g&#46; Dipole-Dipole&#44; Wenner-Schlumberger&#41; of many electrodes connected to resistivity equipment&#46; Resistivity data are then processed to obtain a resistivity cross-section &#40;<a class="elsevierStyleCrossRef" href="#bib0105">Loke&#44; 2013</a>&#41;&#46; As a result of interpretation&#44; true layers resistivity and their thickness are estimated&#46;</p><p id="par0015" class="elsevierStylePara elsevierViewall">The application of EMP method involves measuring the response of the subsurface to an electromagnetic field&#46; An electromagnetic field is generated by a transmitter antenna&#44; inducing eddy currents within the ground&#46; These induced current generate a secondary magnetic field&#46; Both primary and secondary magnetic fields are measured in a receiver antenna&#46; The ground conductivity due to geological characteristics&#44; conductive materials &#40;metal objects&#41; and contaminants can be calculated from the ratio of the secondary and primary magnetic fields &#40;<a class="elsevierStyleCrossRef" href="#bib0085">Keller and Frischknecht&#44; 1966</a>&#41;&#46; The EMP results&#44; although not providing detailed lithology &#40;layers and their thicknesses&#41; information&#44; can quickly determine the horizontal changes in soil apparent conductivity &#40;e&#46;g&#46; hydrocarbon contamination plume&#41; at different study depths&#46; The electromagnetic measurements are sensitive to buried elongated conductors such as metallic pipes&#44; electric lines&#44; sanitary sewer&#44; etc&#46; These are usually recognized by the large meter fluctuations which occur in short distance&#46; When the antennas are oriented perpendicular to the elongated conductor&#8217;s axis&#44; a minimum conductivity value will be registered &#40;reaching negative values&#41;&#46; When the antennas are parallel and close to the conductor&#8217;s axis&#44; conductivity values will have a maximum &#40;<a class="elsevierStyleCrossRef" href="#bib0055">Geonics Limited&#44; 2010</a>&#41;&#46; In this work&#44; as part of the survey technique&#44; to evaluate the magnitude of electromagnetic interference from metal objects in EMP measurements&#44; soil conductivity measurements were performed to two orthogonal directions of the antennas&#46;</p><p id="par0020" class="elsevierStylePara elsevierViewall">Volatile organic compounds &#40;VOC&#41; are the most common contaminants encountered at hydrocarbon contaminated sites&#46; VOC survey is applicable under a variety of geological setting&#46; Accurate VOC determinations are needed to assess the extent of contamination to make decisions for appropriate remedial action&#46; The evaluation of subsurface organic vapors is based on the physical phenomena of hydrocarbons volatilization given by the Henry law &#40;<a class="elsevierStyleCrossRef" href="#bib0095">Lin and Chou&#44; 2006</a>&#41;&#44; as well as the site characteristics&#46; It has been demonstrated that the analysis of gases or vapors is a good screening technique in hydrocarbon contaminated sites&#44; with GWT depths between 2 to 10<span class="elsevierStyleHsp" style=""></span>m &#40;<a class="elsevierStyleCrossRef" href="#bib0010">API&#44; 1991</a>&#59; Ochoa <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0125">2007</a>&#41;&#46; Determination of VOC is usually performed in situ using a photoionization detector&#46; Using this equipment&#44; it is possible to detect a wide range of compounds in the gasoline to diesel range&#46;</p><p id="par0025" class="elsevierStylePara elsevierViewall">As a result of digging for a water cistern in a basement of an apartment building&#44; a gasoline spill was detected&#46; ERT and EMP methods were applied&#44; as well as VOC measurements&#44; in order to define the contamination plume and to guide the sampling activities&#46; Through the application of the VOC&#44; ERT and EMP methods&#44; it was possible to calculate the dimensions of the affected area&#46; Laboratory analyses of free-product samples suggest the existence of several contamination events with the presence of recent and mature hydrocarbon contaminants&#46;</p></span><span id="sec0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0030">Site background</span><p id="par0030" class="elsevierStylePara elsevierViewall">The site is located in a popular neighborhood of Mexico City between 2&#44;240 and 2&#44;244 m&#46;a&#46;s&#46;l&#46; The geological composition of the site belongs <a name="p185"></a>to the sedimentary Mexico City basin and Texcoco ex-lake&#8217;s west shore &#40;Mar&#237;n-C&#243;rdova <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0110">1986</a>&#41;&#46; The stratification sequence showed low permeability clay and silt within fine and medium sand lenses&#46; The groundwater table &#40;GWT&#41; was between 3&#46;75 and 5&#46;00<span class="elsevierStyleHsp" style=""></span>m in the central and northern portions of the site&#44; meanwhile&#44; in the southern portion&#44; near to gas station&#44; the GWT can reach up to 9&#46;00<span class="elsevierStyleHsp" style=""></span>m depth&#46; The permeability coefficient rate was 1&#46;0<span class="elsevierStyleHsp" style=""></span>&#215;<span class="elsevierStyleHsp" style=""></span>10-6 to 1&#46;0<span class="elsevierStyleHsp" style=""></span>&#215;<span class="elsevierStyleHsp" style=""></span>10-7<span class="elsevierStyleHsp" style=""></span>cm&#47;s &#40;low permeability&#41;&#46;</p><p id="par0035" class="elsevierStylePara elsevierViewall">A paved &#40;main&#41; street runs from southwest to northeast along 350<span class="elsevierStyleHsp" style=""></span>m &#40;<a class="elsevierStyleCrossRef" href="#f0005">Figure 1</a>&#41;&#46; As a result of digging for a water cistern in a basement of an apartment building&#44; a hydrocarbon spill with gasoline-like odor from a thin layer at an approximate depth of 5<span class="elsevierStyleHsp" style=""></span>m was detected&#46; The spill point is about 100<span class="elsevierStyleHsp" style=""></span>m from a gas station&#44; and about 50<span class="elsevierStyleHsp" style=""></span>m from small factories with solvents and fuel storage tanks&#44; indicating the probable existence of active contamination sources &#40;<a class="elsevierStyleCrossRef" href="#f0005">Figure 1</a>&#41;&#46; Indirect methods were applied to map the contaminated zones and to select the soil boring locations&#44; defining a study area of 5&#46;3 ha&#46;</p><elsevierMultimedia ident="f0005"></elsevierMultimedia></span><span id="sec0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0035">Application of geoelectrical and VOC methods&#58; configuration of the contamination plume</span><span id="sec0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0040">Application of VOC measurements</span><p id="par0040" class="elsevierStylePara elsevierViewall">Subsurface vapors were measured in situ to assess the content of VOC&#46; The methodology to measure VOC has been tested and improved since 1992 to allow a rapid measurement &#40;screening&#41; of the most likely occurrence and distribution of hydrocarbons in the subsurface and thus select the sites to perform the drilling and soil sampling&#46; Sampling equipment including a specialized hammer and a hammer sampler probe&#44; allows by vacuum&#44; the extraction of vapor from subsoil&#46; VOC content in subsoil can then be determined using a portable photoionization detector &#40;PID&#41;&#44; which can measure concentrations from ppb to up to 10&#44;000 ppm&#46; Since the presence of VOC in the subsurface originated from the hydrocarbons contaminants are quantified&#44; this method could be considered as semi-indirect&#46; VOC were measured at 91 selected points&#46;<a name="p186"></a></p></span><span id="sec0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0045">Application of ERT method</span><p id="par0045" class="elsevierStylePara elsevierViewall">Three ERT parallel profiles were performed on Main Street &#40;<a class="elsevierStyleCrossRef" href="#f0005">Figure 1</a>&#41; in order to obtain resistivity anomalies associated with the presence of hydrocarbon-contaminated soils&#46; A total of 64 ERT measurements points were settled&#46; ERT survey was carried out using a great number &#40;~50&#41; of electrodes placed along each profile with a constant interval of 4<span class="elsevierStyleHsp" style=""></span>m&#44; using AB&#47;2 spacing of a Wenner-Schlumberger array from 6 to 42<span class="elsevierStyleHsp" style=""></span>m&#44; ensuring a maximal study depth of 15<span class="elsevierStyleHsp" style=""></span>m&#46; Spacing between sounding centers was 8<span class="elsevierStyleHsp" style=""></span>m&#46;</p></span><span id="sec0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0050">Application of EMP method</span><p id="par0050" class="elsevierStylePara elsevierViewall">Using the EM31-MK2 equipment &#40;<a class="elsevierStyleCrossRef" href="#bib0055">Geonics Limited&#44; 2010</a>&#41;&#44; the horizontal changes in soil apparent conductivity for maximal study depth of 6<span class="elsevierStyleHsp" style=""></span>m is determined&#46; Taking into account that in the most of the site the local GWT depth varies between 3&#46;75<span class="elsevierStyleHsp" style=""></span>m &#8211; 5&#46;00<span class="elsevierStyleHsp" style=""></span>m&#44; it is feasible to use the EM31-MK2 equipment to detect the hydrocarbon contamination zones in soil&#44; subsoil and groundwater&#44; while in the southern end of the site &#40;GWT depth<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>9&#46;00<span class="elsevierStyleHsp" style=""></span>m&#41;&#44; EMP is feasible to detect the contamination in soil and subsoil&#44; but not in the groundwater&#46; The EMP survey was carried out considering the electromagnetic interference of the buried elongated conductors&#46; According to our work experience using EM31-MK2 in urban and industrial sites &#40;<a class="elsevierStyleCrossRef" href="#bib0065">IMP 2006</a>&#59; <a class="elsevierStyleCrossRef" href="#bib0070">2006a</a>&#59; <a class="elsevierStyleCrossRef" href="#bib0075">2008</a>&#59; <a class="elsevierStyleCrossRef" href="#bib0080">2013</a>&#59; Mendez-Velarde <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0115">2012</a>&#41;&#44; when the difference between conductivity values recorded to two orthogonal directions of the antennas is more than 10&#37;&#44; the EMP station is rejected and a new measuring point is selected&#44; otherwise the average value can be used for the data reduction&#46; In this way&#44; we ensured that variations in the electromagnetic field are given only by variations in soil conductivity&#46; After removing the measurement points affected by electromagnetic noise&#44; 306 EMP data were recorded and an apparent resistivity map was made&#46;</p></span></span><span id="sec0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0055">Results and discussion</span><p id="par0055" class="elsevierStylePara elsevierViewall">The results of the application of ERT&#44; EMP and VOC methods were processed using software SURFER 8 &#40;<a class="elsevierStyleCrossRef" href="#bib0060">Golden Software Inc&#46;&#44; 2002</a>&#41; with minimum curvature algorithm&#46; The minimum curvature gridding provides reasonable maps with satisfactory smoothing of the field lines &#40;<a class="elsevierStyleCrossRef" href="#bib0025">Briggs&#44; 1974</a>&#41;&#44; widely used in the earth sciences &#40;<a class="elsevierStyleCrossRef" href="#bib0140">Ontario Geological Survey&#44; 2003</a>&#59; Orfanos and Apostolopoulos&#44; <a class="elsevierStyleCrossRef" href="#bib0145">2012</a>&#41;&#44; including geoelectric methods &#40;Korhonen <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0090">2005</a>&#59; <a class="elsevierStyleCrossRef" href="#bib0180">Siemon&#44; 2009</a>&#41;&#46;</p><span id="sec0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0060">VOC data interpretation</span><p id="par0060" class="elsevierStylePara elsevierViewall">There are no national or international normative values that include normal or natural conditions of VOC for hydrocarbon contaminated soils&#46; However&#44; it has been observed that an anomalous value &#40;greater than background&#41; is evidence of contamination phenomena &#40;<a class="elsevierStyleCrossRef" href="#bib0015">Arpel&#44; 1992</a>&#41;&#46; Fischer <span class="elsevierStyleItalic">et al</span>&#46; &#40;<a class="elsevierStyleCrossRef" href="#bib0050">1996</a>&#41; studied a gasoline-contaminated site and they considered that VOC<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>21<span class="elsevierStyleHsp" style=""></span>&#177;<span class="elsevierStyleHsp" style=""></span>2 ppm correspond to low contamination levels&#46; Based on our experience &#40;Ochoa <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0130">2002</a>&#59; Delgado-Rodr&#237;guez <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0030">2006</a>&#44; Mendez-Velarde <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0115">2012</a>&#41;&#44; we had determined that in hydrocarbons contaminated sites VOC values greater than 20 ppm are associated with presence of hydrocarbons&#44; either as free product&#44; absorbed in the subsurface or dissolved in groundwater&#46;</p><p id="par0065" class="elsevierStylePara elsevierViewall">Fresh gasoline contamination presents high VOC &#40;&#62;<span class="elsevierStyleHsp" style=""></span>20 ppm&#41; concentration&#46; Low VOC &#40;&#60;<span class="elsevierStyleHsp" style=""></span>20 ppm&#41; values could indicate the presence of clean soil or soil contaminated by mature hydrocarbons&#46; <a class="elsevierStyleCrossRef" href="#f0010">Figure 2</a> shows some plumes with high VOC concentrations &#40;dark zones&#44; <a class="elsevierStyleCrossRef" href="#f0010">Figure 2</a>&#41;&#44; indicating the presence of fresh contaminants in the subsoil&#59; one of them possibly related to the gas station&#46;</p><elsevierMultimedia ident="f0010"></elsevierMultimedia><p id="par0070" class="elsevierStylePara elsevierViewall">In sites with an active contamination source it is possible to have both degraded contaminants &#40;low VOC values&#41; and fresh contaminants &#40;high VOC values&#41;&#46; In the spill point&#44; such as in zone with clean soil&#44; low VOC values are observed&#44; indicating the possible existence of degraded hydrocarbon contaminants in the subsoil in zones with low values of VOC&#46; Because of this&#44; ERT and EMP methods are applied since they are effective for mapping mature contamination plumes&#46;</p></span><span id="sec0045" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0065">Statistical analysis of ERT data</span><p id="par0075" class="elsevierStylePara elsevierViewall"><a class="elsevierStyleCrossRef" href="#f0015">Figure 3</a> shows the statistical distribution &#40;apparent resistivity vs&#46; AB&#47;2 distances&#41; from 64 ERT measurements points&#46; The legend represents the occurrence frequency values&#46; In general&#44; the apparent resistivity values are below of 20<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m&#44; even in the vadose zone &#40;minimal depth of GWT is 3&#46;75<span class="elsevierStyleHsp" style=""></span>m&#41;&#44; which means the clay content in soil is significant at different study depths&#46; The mean curve &#40;curve H&#44; <a class="elsevierStyleCrossRef" href="#f0015">Figure 3</a>&#41; characterizes the subsurface up to 15<span class="elsevierStyleHsp" style=""></span>m depth by a three layer curve &#40;type H&#41; with low resistivity contrast&#46; In most of the SEV&#44; the resistivity decreases from 10 to 7&#46;8<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m &#40;first and second layer&#41; which marks the transition from a semi-saturated to saturated clayey sediments&#44; respectively&#44; followed by a third layer &#40;AB&#47;2<span class="elsevierStyleHsp" style=""></span>&#62;<span class="elsevierStyleHsp" style=""></span>30<span class="elsevierStyleHsp" style=""></span>m&#41; with <a name="p187"></a><a name="p188"></a>lower clay content &#40;&#961;a<span class="elsevierStyleHsp" style=""></span>~<span class="elsevierStyleHsp" style=""></span>9<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m&#41;&#46; Apparent resistivity values below 6&#46;4<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m are outlined in a cloud of data &#40;dashed line contour&#44; zone C&#44; <a class="elsevierStyleCrossRef" href="#f0015">Figure 3</a>&#41;&#44; indicating the presence of low resistivity anomalies &#40;mature contamination&#41; for some ERT points&#44; mainly for AB&#47;2<span class="elsevierStyleHsp" style=""></span>&#62;<span class="elsevierStyleHsp" style=""></span>10<span class="elsevierStyleHsp" style=""></span>m or study depth<span class="elsevierStyleHsp" style=""></span>&#8805;<span class="elsevierStyleHsp" style=""></span>5<span class="elsevierStyleHsp" style=""></span>m &#40;second layer&#41;&#46;</p><elsevierMultimedia ident="f0015"></elsevierMultimedia></span><span id="sec0050" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0070">ERT data interpretation&#46; Defining the geoelectric boundary between clean and contaminated soil</span><p id="par0080" class="elsevierStylePara elsevierViewall">The RES2DInv software was used for the interpretation process and an interpreted geoelectrical section was obtained for each profile&#46; The RES2DInv software uses the smoothness-constrained least-squares method inversion technique to produce a 2D model of the subsurface&#46; Two different variations of the smoothness constrained least-squares method are provided&#59; one optimized for areas where the subsurface resistivity varies in a smooth manner&#44; and another optimized for areas with sharp boundaries &#40;<a class="elsevierStyleCrossRef" href="#bib0100">Loke and Barker&#44; 1996</a>&#41;&#46; The obtained geoelectrical sections have the same number of layers with same thicknesses along each profile&#44; giving great advantage to make interpreted resistivity maps for different study depths &#40;e&#46;g&#46; groundwater table depth&#44; contamination plume&#44; etc&#41;&#46;</p><p id="par0085" class="elsevierStylePara elsevierViewall"><a class="elsevierStyleCrossRef" href="#f0020">Figure 4</a> shows the interpreted resistivity sections for ERT<span class="elsevierStyleInf">1</span>&#44; ERT<span class="elsevierStyleInf">2</span> and ERT<span class="elsevierStyleInf">3</span> profiles with three main layers&#58; a superficial resistive layer consisting of sandy-clayey deposits with resistivity range from 8 to 20<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m&#44; a second layer where clay content increases with resistivity ranging from 1&#46;5 to 9<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m and a resistive third layer given by the decrease in clay content with resistivity ranging from 8 to 35<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m&#46;</p><elsevierMultimedia ident="f0020"></elsevierMultimedia><p id="par0090" class="elsevierStylePara elsevierViewall">Taking into account the existence of high clay content in the subsoil and the characterization of mature hydrocarbon contamination as low resistivity anomaly&#44; we need to define the geoelectric boundary between clean and contaminated soil&#46; For this purpose&#44; we used in the present work a conductivity model for unconsolidated formations and the &#8220;Petro-Win&#8221; software for calculation of the soil resistivity developed by Ryjov and Shevnin &#40;<a class="elsevierStyleCrossRef" href="#bib0150">2002</a>&#41;&#46; This model considers the geometrical microstructure of the components as well as electrochemical processes occurring in the soil for a wide range of the pore-water salinity and clay content&#46; Once groundwater &#40;or salinity&#41; and soil resistivity are known&#44; clay content and porosity are estimated for clean soil&#44; and the geoelectric boundary is defined&#46; The characteristics of the conductivity model&#44; the procedure to determine the groundwater &#40;from in-field measurements&#41; and soil &#40;from lab measurements&#41; resistivity&#44; and the equations for calculate the soil petrophysical parameters &#40;including clay content and porosity&#41; are explained in detail in Shevnin <span class="elsevierStyleItalic">et al</span>&#46; &#40;<a class="elsevierStyleCrossRef" href="#bib0170">2006</a>&#59; <a class="elsevierStyleCrossRef" href="#bib0175">2007</a>&#41; and Delgado-Rodr&#237;guez <span class="elsevierStyleItalic">et al</span>&#46; &#40;<a class="elsevierStyleCrossRef" href="#bib0040">2012</a>&#41;&#46;</p><p id="par0095" class="elsevierStylePara elsevierViewall">In order to define the geoelectric boundary&#44; four wells located far enough from the spill point &#40;<a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>&#41; were drilled in the residential zone under construction using a Geoprobe System &#40;<a class="elsevierStyleCrossRef" href="#f0025">Figure 5</a>&#41;&#46; Four soil samples &#40;one per <a name="p189"></a>well&#41; were collected from the layer noticeably more argillaceous&#44; at depths of 6 to 7<span class="elsevierStyleHsp" style=""></span>m &#40;second layer&#44; <a class="elsevierStyleCrossRef" href="#f0020">Figure 4</a>&#41; and then analyzed in the laboratory&#44; resulting in a clay content range between 37&#37; and 50&#37; &#40;<a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>&#41;&#46; Likewise&#44; groundwater samples were collected from local aquifer&#44; resulting in a mean resistivity values of 5&#46;9<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m at 20<span class="elsevierStyleHsp" style=""></span>&#176;C&#44; which means a salinity of 1 g&#47;l&#46;</p><elsevierMultimedia ident="f0025"></elsevierMultimedia><elsevierMultimedia ident="tbl0005"></elsevierMultimedia><p id="par0100" class="elsevierStylePara elsevierViewall">In <a class="elsevierStyleCrossRef" href="#f0030">Figure 6</a> the results of theoretical calculations with the &#8220;Petro-Win&#8221; software are shown&#46; Soil resistivity is considered as a function of water salinity &#40;NaCl content at 20&#176;C&#41;&#46; Soil resistivity curves for different sand and clay proportions are displayed&#58; curve for sand &#40;in the upper part of <a class="elsevierStyleCrossRef" href="#f0015">Figure 3A</a>&#44; 0&#37; clay&#44; and 25&#37; porosity&#41; and curve for pure clay &#40;in the lower part of <a class="elsevierStyleCrossRef" href="#f0015">Figure 3A</a>&#44; 100&#37; clay&#44; and 55&#37; porosity&#41;&#46; Water curve &#40;dashed curve&#41; gives us the relation between water resistivity and water salinity&#59; while the vertical dotted line represent the groundwater salinity mean value of 1 g&#47;l for the study area&#46; Two horizontal dotted lines show the resistivity range 4&#46;5<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m to 6&#46;1<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m for soils with clay content between 37&#37; -50&#37; and pore-water salinity 1 g&#47;l&#44; being 4&#46;5<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m the geoelectric boundary between clean and contaminated soil&#46; Resistivity values less than 4&#46;5<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m correspond to mature oil contaminated soils&#59; however&#44; low levels of hydrocarbons contamination may be present <a name="p190"></a>in soils with resistivity values within the aforementioned resistivity interval&#46; Resistivity values greater than 6&#46;1<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m indicate that there is no mature contamination&#46;</p><elsevierMultimedia ident="f0030"></elsevierMultimedia><elsevierMultimedia ident="f0035"></elsevierMultimedia><p id="par0105" class="elsevierStylePara elsevierViewall">The second layer presents low resistivity zones associated with the presence of mature hydrocarbons contamination&#46; Using the interpreted information from <a class="elsevierStyleCrossRef" href="#f0020">Figure 4</a>&#44; the behavior of the resistivity on the second layer &#40;local aquifer&#41; can be mapped with high resolution&#46; A map of interpreted resistivity for the second layer is shown in <a class="elsevierStyleCrossRef" href="#f0035">Figure 7A</a> where the dark zones may indicate the presence of mature contamination&#46;<a name="p191"></a></p></span><span id="sec0055" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0075">EMP data interpretation</span><p id="par0110" class="elsevierStylePara elsevierViewall">The maximum study depth with EM31-MK2 is 6<span class="elsevierStyleHsp" style=""></span>m&#46; Considering the conductive sediments of the site&#44; the maximum study depth corresponding&#44; in <a class="elsevierStyleCrossRef" href="#f0015">Figure 3</a> to AB&#47;2<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>12 to 13<span class="elsevierStyleHsp" style=""></span>m&#44; and higher values of the occurrence frequency&#44; the &#961;a range from 7&#46;5 to 9&#46;5<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m is defined as representative of the lithological variations in the study site for study depth equal to 6<span class="elsevierStyleHsp" style=""></span>m&#46;</p><p id="par0115" class="elsevierStylePara elsevierViewall"><a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a> shows the apparent resistivity map given by the EMP method&#46; Three main &#40;southern&#44; central&#44; and northern&#41; low resistivity anomalies &#40;dark zones&#44; <a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>&#41; are observed&#46; The southern anomalous zone includes the railroad maintenance area &#40;<a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>&#41; where sulfur powder can be seen dispersed on the ground surface&#46; Due to biodegradation processes&#44; sulfur can cause an acidic environment&#44; which generates salts in the subsoil and the consequent low resistivity anomaly&#46; Therefore&#44; the existence of chemical contamination is possible due to the presence of sulfur&#44; therefore railroad maintenance area will be considered as contaminated by sulfur&#46; The central anomalous zone is located within a residential zone &#40;<a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>&#41;&#44; coinciding with the drainage system&#46; Due to land subsidence in the Valley of Mexico&#44; frequently the drainage system&#44; consisting of concrete pipelines&#44; is broken and sewage leakages occur&#46; In this case&#44; we observed part of the sewage emerging on the terrain surface&#44; resulting in low resistivity anomaly&#46; Furthermore&#44; the VOC values in this zone are almost zero &#40;<a class="elsevierStyleCrossRef" href="#f0010">Figure 2</a>&#41;&#44; ensuring the absence of recent hydrocarbon contamination&#46; Therefore&#44; we propose that sewage is causing this low resistivity anomalies inside residential zone &#40;<a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>&#41;&#46; These two areas contaminated &#40;by sulfur and sewage&#41; should not be considered in the setting of hydrocarbon contamination plumes &#40;see zone framed with dashed white line in <a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>&#41;&#46;</p><p id="par0120" class="elsevierStylePara elsevierViewall">The northern anomaly zone is located in the area where a new residential zone is being built&#44; including the spill point &#40;black diamond&#44; <a class="elsevierStyleCrossRef" href="#f0035">Figure 7B</a>&#41;&#46; The cause of this anomaly zone is the presence of degraded hydrocarbons &#40;mature contamination&#41;&#46;</p><p id="par0125" class="elsevierStylePara elsevierViewall">Zones with high apparent resistivity values indicate the absence of degraded hydrocarbon contaminants in the subsurface and the possible presence of recent hydrocarbons contamination&#46; However&#44; these high values are influenced by the superficial layer of subsoil&#46; The superficial soil resistivity is determined not only by the clay content but also by its moisture&#44; depending on the topographical elevations changes&#44; masking the recent contaminants effect&#46; This is why EMP method&#44; as well as ERT&#44; has low resolution in detecting fresh hydrocarbons contamination plumes&#46;</p><p id="par0130" class="elsevierStylePara elsevierViewall">In general&#44; there is a good correspondence between ERT and EMP resistivity maps &#40;<a class="elsevierStyleCrossRef" href="#f0035">Figure 7</a>&#41;&#44; showing possible migration routes of the contaminants in the subsurface&#46;</p></span><span id="sec0060" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0080">Integrated data map from EMP&#44; ERT&#44; and VOC results&#46;</span><p id="par0135" class="elsevierStylePara elsevierViewall">High VOC values &#40;high level of volatiles&#41; indicate the presence fresh contamination in the subsurface&#46; In contaminated zones &#40;e&#46;g&#46; around of the spill point&#41;&#44; where low VOC values &#40;VOC<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>1&#46;2 ppm&#41; such as clean soil are observed&#44; low resistivity anomalies &#40;&#961;<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>4&#46;5<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m&#41; confirm the existence degraded contamination&#46; Due to this&#44; it is necessary to integrate the geoelectric &#40;ERT and EMP&#41; and VOC methods results in order to define and to map all contamination plumes at the site and to focus the drilling and soil&#47;free-product sampling&#46;</p><p id="par0140" class="elsevierStylePara elsevierViewall">To make the integral map&#44; a grid of 5<span class="elsevierStyleHsp" style=""></span>&#215;<span class="elsevierStyleHsp" style=""></span>5<span class="elsevierStyleHsp" style=""></span>m for the study site was created&#44; and values &#40;rather the logarithm of the values&#41; obtained by each method were interpolated&#46; The grid size is equal to the study area&#44; with an approximate value of 5&#46;3 ha&#46; At each grid point&#44; the applied methods receive a weight according to the interval wherein their values are &#40;<a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>&#41;&#46;</p><elsevierMultimedia ident="tbl0010"></elsevierMultimedia><p id="par0145" class="elsevierStylePara elsevierViewall">The parameters or variables that integrate the map are&#58; gas concentration &#40;VOC&#41; in ppm&#44; true resistivity &#40;ERT&#41; in<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m and apparent resistivity &#40;EMP&#41; in<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m&#46; Each variable&#44; depending on the values range&#44; generates a weight &#40;or degree of reliability&#44; X<span class="elsevierStyleInf">ij</span>&#41; of the anomalous zone&#46; The obtained values of the indirect methods &#40;ERT and EMP&#41; receive weights between 0 and 5&#44; while VOC&#44; considered as semi-indirect method&#44; their values receive a weight range between 0 and 7 &#40;<a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>&#41;&#46; Based on the petrophysical modeling performed in clean soil samples &#40;<a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>&#44; <a class="elsevierStyleCrossRef" href="#f0030">Figure 6</a>&#41;&#44; the ERT interval 6&#46;1<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>&#961;<span class="elsevierStyleHsp" style=""></span>&#60;14<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m gets weight 0 since it is not related to the presence of neither fresh or mature contaminant but rather is the sediments resistivity range of the site&#44; while the other weights values are distributed as follows&#58; 3 to 5 and 1 to 2&#44; for low &#40;high resolution&#41; and high &#40;lower resolution&#41; resistivity anomalies&#44; respectively&#46; In a similar manner&#44; based on the correspondence between apparent resistivity <a name="p192"></a>and interpreted resistivity maps &#40;<a class="elsevierStyleCrossRef" href="#f0035">Figure 7</a>&#41;&#44; EMP &#40;apparent resistivity&#41; values receive weights 1 and 2 to high resistivity anomalies and 3 to 5 to low resistivity anomalies&#46; Taking into account the statistical distribution of the apparent resistivity values of the <a class="elsevierStyleCrossRef" href="#f0015">Figure 3</a>&#44; the interval 7&#46;5<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>&#961;a<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>9&#46;5<span class="elsevierStyleHsp" style=""></span>Ohm&#46;m receives weight 0&#46; The index for VOC varies between 1 and 7 depending on the increase of VOC value from 20 to 179 ppm&#46; VOC values less than 20 ppm will have weight 0 &#40;<a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>&#41;&#46;</p><p id="par0150" class="elsevierStylePara elsevierViewall">The X<span class="elsevierStyleInf">ij</span> calculated for each method <span class="elsevierStyleItalic">i&#44;</span> in each grid point <span class="elsevierStyleItalic">j</span> is multiplied by a coefficient MCi &#40;MC<span class="elsevierStyleInf">VOC</span><span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>5 for VOC&#44; MC<span class="elsevierStyleInf">ERT</span><span class="elsevierStyleHsp" style=""></span>&#61;4 for ERT and MC<span class="elsevierStyleInf">EMP</span><span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>3 for EMP&#41;&#46; Finally&#44; the average of all the values resulting from the multiplication &#40;integral parameter&#44; IP&#41; is calculated by the expression&#58;</p><p id="par0155" class="elsevierStylePara elsevierViewall"><elsevierMultimedia ident="eq0005"></elsevierMultimedia></p><p id="par0160" class="elsevierStylePara elsevierViewall">Where&#58; IP<span class="elsevierStyleInf"><span class="elsevierStyleItalic">j</span></span> &#8211;integral parameter value of the grid point <span class="elsevierStyleItalic">j</span>&#46;</p><p id="par0165" class="elsevierStylePara elsevierViewall">X<span class="elsevierStyleInf"><span class="elsevierStyleItalic">ij</span></span> &#8211;weight value calculated from field value of the method <span class="elsevierStyleItalic">i</span> in grid point <span class="elsevierStyleItalic">j</span>&#46;</p><p id="par0170" class="elsevierStylePara elsevierViewall">MC<span class="elsevierStyleInf"><span class="elsevierStyleItalic">i</span></span> &#8211;multiplication coefficient for method <span class="elsevierStyleItalic">i</span>&#46;</p><p id="par0175" class="elsevierStylePara elsevierViewall">N<span class="elsevierStyleInf"><span class="elsevierStyleItalic">j</span></span> &#8211;Total number of methods applied in grid point <span class="elsevierStyleItalic">j</span> &#40;N<span class="elsevierStyleInf"><span class="elsevierStyleItalic">j</span></span><span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>1&#44; 2 or 3&#41;&#46;</p><p id="par0180" class="elsevierStylePara elsevierViewall">It should be noted that the ranges and weights in <a class="elsevierStyleCrossRef" href="#tbl0010">Table &#40;2&#41;</a> are valid for the site studied in the present study&#46; New sites require a particular analysis of the obtained data&#44; defining new ranges and assigned weights&#46;</p><p id="par0185" class="elsevierStylePara elsevierViewall"><a class="elsevierStyleCrossRef" href="#tbl0015">Tables 3</a> and <a class="elsevierStyleCrossRef" href="#tbl0020">4</a> show the calculation procedure using <a class="elsevierStyleCrossRef" href="#eq0005">equation &#40;1&#41;</a> in grid portions corresponding to two small zones predominantly contaminated with fresh and mature hydrocarbons&#44; respectively&#46; Near to well S<span class="elsevierStyleInf">1</span>&#44; the zone with fresh contaminants shows high VOC values &#40;<a class="elsevierStyleCrossRef" href="#tbl0015">Table 3</a>&#41;&#44; while low resistivity and VOC values highlight in the zone with degraded contaminants located close to the spill point &#40;<a class="elsevierStyleCrossRef" href="#tbl0020">Table 4</a>&#41;&#46;</p><elsevierMultimedia ident="tbl0015"></elsevierMultimedia><elsevierMultimedia ident="tbl0020"></elsevierMultimedia><p id="par0190" class="elsevierStylePara elsevierViewall">The IP<span class="elsevierStyleInf">j</span> values are mapped and shown in <a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>&#46; Three contamination plumes are observed in the integrated map&#46;</p><elsevierMultimedia ident="f0040"></elsevierMultimedia><p id="par0195" class="elsevierStylePara elsevierViewall">The first plume starts at the southwestern corner of the study area and extends down Main Street to the center of the site&#46; Taking into account its connection with gas station and the high values of VOC in this plume &#40;presence of fresh hydrocarbons&#41;&#44; we can affirm that the gas station is an active contamination source&#46; Four months after the completion of this work&#44; as a result of an integrity testing of the underground storage tank&#44; a gasoline leaking point was found and repaired in the gas station&#46; The second plume&#44; located in the residential zone under construction&#44; is related with spill point&#44; where medium and low values of VOC and low resistivity anomalies indicate the existence de mature hydrocarbon contamination&#46; A third contaminated zone located in the central avenue is characterized by medium values of VOC and high resistivity values&#46; This zone was related to the basement of a furniture factory&#44; which uses solvents and white gas for painting and cleaning activities&#46; The factory owner recognized that oil-based paints and solvents are poured directly on the soil &#40;personal communication&#41;&#46;<a name="p193"></a></p></span></span><span id="sec0065" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0085">Verifying indirect results</span><p id="par0200" class="elsevierStylePara elsevierViewall">Since benzene&#44; toluene&#44; ethylbenzene&#44; and xylenes &#40;BTEX&#41; are some of the main VOC found in petroleum derivatives such as gasoline&#59; we performed a measurement of the concentrations of each of their constituents in order to verify the anomalies&#46; BTEX compounds are notorious due to the contamination of soil and groundwater by gasoline &#40;<a class="elsevierStyleCrossRef" href="#bib0045">EEA&#44; 2010</a>&#41;&#46; Contamination typically occurs near petroleum and natural gas production sites&#44; petrol stations&#44; and other areas with underground or above-ground storage tanks&#44; containing gasoline &#40;EEA&#44; <a class="elsevierStyleCrossRef" href="#bib0045">2010</a>&#41;&#46; Therefore&#44; these compounds might be good indicator of recent contamination by gasoline&#46; Although BTEX ratio were obtained to this purpose&#44; it is acknowledge that inferring the age of a release based on BTEX ratios alone could be a valid approach only in well constrained situations&#44; due to the rate of change of the gasoline BTEX ratio is affected by many site-specific variables&#46; Another reason to measure BTEX in a gasoline contamination event was to comply with the current Mexican regulation &#40;<a class="elsevierStyleCrossRef" href="#bib0160">SEMARNAT&#44; 2005</a>&#41;&#46;</p><p id="par0205" class="elsevierStylePara elsevierViewall">In addition to BTEX&#44; light oil fraction &#40;LOF&#41; was measured&#46; LOF term refers to all volatile compounds which cover the range of carbon atoms from C<span class="elsevierStyleInf">5</span> to C<span class="elsevierStyleInf">10</span>&#46; The measurement of this fraction was performed to complement the measurement of all volatile compounds that may be present on the site&#44; complying with current Mexican regulation on soil contamination&#46;</p><span id="sec0070" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0090">Soil LOF Analysis</span><p id="par0210" class="elsevierStylePara elsevierViewall">Using the integrated map &#40;<a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>&#41;&#44; the drilling activities were conducted to the specific contaminated areas&#46; Using a Geoprobe System &#40;<a class="elsevierStyleCrossRef" href="#f0025">Figure 5</a>&#41;&#44; six monitoring wells were drilled up to 10<span class="elsevierStyleHsp" style=""></span>m of depth in strategic and topographic relevant points&#44; taking into account the urban infrastructure and the access level to each point&#46; Twenty two soil samples &#40;<a class="elsevierStyleCrossRef" href="#tbl0025">Table 5</a>&#41; were collected in monitoring wells S<span class="elsevierStyleInf">1</span>-S<span class="elsevierStyleInf">5</span> and S<span class="elsevierStyleInf">x</span>&#44; &#40;<a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>&#41;&#46; The analytical results revealed an irregular distribution of LOF depending on the depth ranges from bellow the detection limit to 11312<span class="elsevierStyleHsp" style=""></span>mg&#47;kg&#46; The maximal concentration &#40;11312<span class="elsevierStyleHsp" style=""></span>mg&#47;kg&#41; of the site was detected in S<span class="elsevierStyleInf">4</span> in the interval of depth 3 to 4<span class="elsevierStyleHsp" style=""></span>m&#46; In well S<span class="elsevierStyleInf">1</span>&#44; a concentration value of 1338<span class="elsevierStyleHsp" style=""></span>mg&#47;kg was determinate for interval of depth 9&#46;5 to 10<span class="elsevierStyleHsp" style=""></span>m&#44; corresponding to the GWT depth in the southern end of the site&#46; Other noticeable concentration <a name="p194"></a>value &#40;834<span class="elsevierStyleHsp" style=""></span>mg&#47;kg&#41; was determinate in well S<span class="elsevierStyleInf">2</span> &#40;<a class="elsevierStyleCrossRef" href="#tbl0025">Table 5</a>&#41;&#46; On the other hand&#44; the well S<span class="elsevierStyleInf">x</span> shows significant value &#40;2071<span class="elsevierStyleHsp" style=""></span>mg&#47;kg&#41; of LOF in sample of soil collected near to ground surface &#40;depth<span class="elsevierStyleHsp" style=""></span>~1&#46;2<span class="elsevierStyleHsp" style=""></span>m&#41;&#44; as evidence of contamination by hydrocarbons poured on the terrain&#46; LOF was very low in wells S<span class="elsevierStyleInf">3</span> and S<span class="elsevierStyleInf">5</span> &#40;<a class="elsevierStyleCrossRef" href="#tbl0025">Table 5</a>&#41;&#46;</p><elsevierMultimedia ident="tbl0025"></elsevierMultimedia></span><span id="sec0075" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0095">BTEX analysis in FP samples</span><p id="par0215" class="elsevierStylePara elsevierViewall">One of the age-dating methods uses benzene plus toluene to ethylbenzene plus xylenes ratios &#40;B&#43;T&#47;E&#43;X&#41;&#46; Use of this ratio minimizes uncertainties related to historical variations in BTEX composition of manufactured gasoline and provides a valuable tool for monitoring environmental changes in a dissolved gasoline plume with time &#40;Stout <span class="elsevierStyleItalic">et al</span>&#46;&#44; <a class="elsevierStyleCrossRef" href="#bib0185">2002</a>&#41;&#46; Although the rate of change of the gasoline BTEX ratio is affected by many site-specific variables&#44; inferring the age of a release based on BTEX ratios alone could be a valid approach only in well constrained situations&#46;</p><p id="par0220" class="elsevierStylePara elsevierViewall">The samples of free product FP<span class="elsevierStyleInf">1</span> and FP<span class="elsevierStyleInf">2</span> collected in well S<span class="elsevierStyleInf">1</span> and recollection trench&#44; respectively &#40;<a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>&#41;&#44; did not present significant changes in the B&#43;T&#47;E&#43;X ratio &#40;<a class="elsevierStyleCrossRef" href="#f0045">Figure 9</a>&#41;&#46; Observations revealed that fuels collected in monitoring S<span class="elsevierStyleInf">1</span> were freshly released products by continuous leaking&#44; as noted above&#46; This could confirm that the free product fluid rapidly migrated to the GWT&#46; Further work is needed to analyse if chemical substantial alteration occurred during its vertical migration into the soil or it may have remained in a relatively unaltered state&#46;</p><elsevierMultimedia ident="f0045"></elsevierMultimedia><p id="par0225" class="elsevierStylePara elsevierViewall">BTEX ratio of free-phase gasoline sample FP<span class="elsevierStyleInf">3</span>&#44; collected in the spill point &#40;<a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>&#41; reached a value of 0&#46;32&#44; as shown in <a class="elsevierStyleCrossRef" href="#f0045">Figure 9</a>&#46; The significant decrease of BTEX ratio on free-phase in sample FP<span class="elsevierStyleInf">3</span> implies a weathering by solubilisation&#44; water washing or biodegradation process&#46; Weathering and BTEX ratios imply that gasoline was transported to the water table and did not undergo substantial alteration during its vertical migration in the soil&#46; Hence&#44; a thin layer of free product was carried through sand lenses to the impermeable clay stratum&#46; Therefore&#44; when advanced alteration of the pattern has occurred due to environmental exposure&#44; it is difficult to estimate&#44; by composition of the free-phase&#44; when the fuel was released&#46; Lead and lead alkyls were absent in the free-phase sample&#44; and is worth noting that regular unleaded gasoline was introduced in 1992&#46;</p><p id="par0230" class="elsevierStylePara elsevierViewall">Based on the results obtained from integral map &#40;<a class="elsevierStyleCrossRef" href="#f0040">Figure 8</a>&#41; and BTEX analysis of FP samples &#40;<a class="elsevierStyleCrossRef" href="#f0045">Figure 9</a>&#41;&#44; three contaminated plumes are characterized and showed in <a class="elsevierStyleCrossRef" href="#f0050">Figure 10</a>&#46;</p><elsevierMultimedia ident="f0050"></elsevierMultimedia><p id="par0235" class="elsevierStylePara elsevierViewall">Plume I&#46; &#8220;Recent Infiltration Zone&#8221;&#44; corresponds to the most recent leakage of regular unleaded gasoline&#46; The characteristics of the weathering processes &#40;evaporation and solubilization&#41; are not significant in the soil and FP samples&#46; The contaminated plume I area is 1280<span class="elsevierStyleHsp" style=""></span>m<span class="elsevierStyleSup">2</span>&#44; with a thickness according on sand layer thickness&#46;</p><p id="par0240" class="elsevierStylePara elsevierViewall">Plume II&#46; Defined as &#8220;soil confined gasoline zone&#8221;&#46; It was contaminated by regular unleaded gasoline released within the last one to five years&#44; based on the BTEX ratio analysis in FP samples&#46; It showed a weathering process including evaporation&#44; solubilisation&#44; and biodegradation for a long time in a low permeability soil layer&#46; Hydrogeology field analysis identified sand lenses confined in low permeability soil layers&#44; the released gasoline could be trapped in a confined sand lens for years&#46; However&#44; site assessment work did not provide hydrogeochemical information from which reliable estimations about spill age could <a name="p195"></a><a name="p196"></a>be drawn based on the BTEX ratios&#46; The plume II area is 1152<span class="elsevierStyleHsp" style=""></span>m<span class="elsevierStyleSup">2</span>&#44; with a volume according to sand lens thickness &#40;~<span class="elsevierStyleHsp" style=""></span>0&#46;5<span class="elsevierStyleHsp" style=""></span>m&#41;&#46;</p><p id="par0245" class="elsevierStylePara elsevierViewall">Plume III&#46; Zone characterized by a type of hydrocarbon different to the regular gasoline founded in plumes I and II&#46; The composition of gasoline found in the shallower part of the subsurface &#40;depth<span class="elsevierStyleHsp" style=""></span>~1&#46;2<span class="elsevierStyleHsp" style=""></span>m&#41; was similar to &#8220;white gas&#8221;&#46; Because of the chemical composition&#44; weathering characteristics&#44; contaminant transport&#44; and hydrocarbons concentration in soils along the monitoring well S<span class="elsevierStyleInf">x</span>&#44; plume III was considered an isolated event&#44; not related with the other two plumes&#44; covering a 160<span class="elsevierStyleHsp" style=""></span>m<span class="elsevierStyleSup">2</span> area&#46;</p><p id="par0250" class="elsevierStylePara elsevierViewall">The sum of the areas of each contamination plumes is 2592<span class="elsevierStyleHsp" style=""></span>m<span class="elsevierStyleSup">2</span>&#44; which almost represent 5&#37; of the study area &#40;5&#46;3 ha&#41;&#44; demonstrating the benefit of using indirect methods for the optimized selection of drilling points and soil sampling depths&#46;</p></span></span><span id="sec0080" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0100">Conclusions</span><p id="par0255" class="elsevierStylePara elsevierViewall">The indirect &#40;ERT&#44; EMP and VOC&#41; methods are efficient tools for studying the hydrocarbons contaminated sites&#44; reducing the number of drilling and soil samples&#46; The high values of VOC mapped the presence of fresh gasoline in the subsoil and suggested that the gas station located at the study site is an active contamination source&#46; Later&#44; from an integrity testing&#44; a gasoline leaking point was found in the underground storage tank of the gas station&#46; However&#44; the considerable degradation of the regular gasoline founded in the surrounding construction area indicates&#44; at least&#44; the existence of a previous contamination event&#46;</p><p id="par0260" class="elsevierStylePara elsevierViewall">The gas station is topographically located at an up gradient from the spill present in the nearby apartment construction&#46; Therefore&#44; gasoline released from buried pipeline would migrate toward the apartment construction area&#46; Mature contaminated zones were defined by ERT and EMP methods as low resistivity anomalies&#46; The ERT&#44; EMP and VOC results were integrated on a map&#44; allowing the final configuration of contamination plumes and the optimization of drilling and soil&#47;free-product sampling&#46;</p><p id="par0265" class="elsevierStylePara elsevierViewall">The affected area by hydrocarbons can be separated in three plumes with different type of contaminants&#58; Plume I&#44; with recent release of regular gasoline&#44; which is connected with the gas station as active contamination source&#59; Plume II corresponds&#44; according to geoelectrical and BTEX analysis results&#44; to mature &#40;weathering and biodegradation&#41; hydrocarbons contamination due to regular unleaded gasoline released within the last one to five years&#59; and a small Plume III&#44; not related with the other two plumes mentioned above&#44; caused by pouring of solvents and white gas on soil&#46;</p><p id="par0270" class="elsevierStylePara elsevierViewall">This study shows the advantages of joint application of ERT&#44; EMP and VOC methods in sites with an active contamination source&#44; where the existence of recent and mature contaminants in subsoil is suspected&#46;<a name="p197"></a></p></span></span>"
    "textoCompletoSecciones" => array:1 [
      "secciones" => array:11 [
        0 => array:3 [
          "identificador" => "xres498006"
          "titulo" => "Resumen"
          "secciones" => array:1 [
            0 => array:1 [
              "identificador" => "abst0005"
            ]
          ]
        ]
        1 => array:2 [
          "identificador" => "xpalclavsec519553"
          "titulo" => "Palabras claves"
        ]
        2 => array:3 [
          "identificador" => "xres498005"
          "titulo" => "Abstract"
          "secciones" => array:1 [
            0 => array:1 [
              "identificador" => "abst0010"
            ]
          ]
        ]
        3 => array:2 [
          "identificador" => "xpalclavsec519552"
          "titulo" => "Keywords"
        ]
        4 => array:2 [
          "identificador" => "sec0005"
          "titulo" => "Introduction"
        ]
        5 => array:2 [
          "identificador" => "sec0010"
          "titulo" => "Site background"
        ]
        6 => array:3 [
          "identificador" => "sec0015"
          "titulo" => "Application of geoelectrical and VOC methods&#58; configuration of the contamination plume"
          "secciones" => array:3 [
            0 => array:2 [
              "identificador" => "sec0020"
              "titulo" => "Application of VOC measurements"
            ]
            1 => array:2 [
              "identificador" => "sec0025"
              "titulo" => "Application of ERT method"
            ]
            2 => array:2 [
              "identificador" => "sec0030"
              "titulo" => "Application of EMP method"
            ]
          ]
        ]
        7 => array:3 [
          "identificador" => "sec0035"
          "titulo" => "Results and discussion"
          "secciones" => array:5 [
            0 => array:2 [
              "identificador" => "sec0040"
              "titulo" => "VOC data interpretation"
            ]
            1 => array:2 [
              "identificador" => "sec0045"
              "titulo" => "Statistical analysis of ERT data"
            ]
            2 => array:2 [
              "identificador" => "sec0050"
              "titulo" => "ERT data interpretation&#46; Defining the geoelectric boundary between clean and contaminated soil"
            ]
            3 => array:2 [
              "identificador" => "sec0055"
              "titulo" => "EMP data interpretation"
            ]
            4 => array:2 [
              "identificador" => "sec0060"
              "titulo" => "Integrated data map from EMP&#44; ERT&#44; and VOC results&#46;"
            ]
          ]
        ]
        8 => array:3 [
          "identificador" => "sec0065"
          "titulo" => "Verifying indirect results"
          "secciones" => array:2 [
            0 => array:2 [
              "identificador" => "sec0070"
              "titulo" => "Soil LOF Analysis"
            ]
            1 => array:2 [
              "identificador" => "sec0075"
              "titulo" => "BTEX analysis in FP samples"
            ]
          ]
        ]
        9 => array:2 [
          "identificador" => "sec0080"
          "titulo" => "Conclusions"
        ]
        10 => array:1 [
          "titulo" => "Bibliography"
        ]
      ]
    ]
    "pdfFichero" => "main.pdf"
    "tienePdf" => true
    "fechaRecibido" => "2013-03-06"
    "fechaAceptado" => "2013-09-03"
    "PalabrasClave" => array:2 [
      "es" => array:1 [
        0 => array:4 [
          "clase" => "keyword"
          "titulo" => "Palabras claves"
          "identificador" => "xpalclavsec519553"
          "palabras" => array:9 [
            0 => "Benceno"
            1 => "Tolueno"
            2 => "Etilbenceno"
            3 => "Xilenos &#40;BTEX&#41;"
            4 => "compuestos org&#225;nicos vol&#225;tiles &#40;COV&#41;"
            5 => "contaminaci&#243;n por hidrocarburos"
            6 => "fuga de gasolina"
            7 => "tomograf&#237;a de resistividad el&#233;ctrica &#40;TRE&#41;"
            8 => "perfilaje electromagn&#233;tico &#40;PEM&#41;"
          ]
        ]
      ]
      "en" => array:1 [
        0 => array:4 [
          "clase" => "keyword"
          "titulo" => "Keywords"
          "identificador" => "xpalclavsec519552"
          "palabras" => array:9 [
            0 => "Benzene"
            1 => "Toluene"
            2 => "Ethylbenzene"
            3 => "Xylenes &#40;BTEX&#41;"
            4 => "hydrocarbons contamination"
            5 => "volatile organic compounds &#40;VOC&#41;"
            6 => "gasoline spill"
            7 => "electrical resistivity tomography &#40;ERT&#41;"
            8 => "electromagnetic profiling &#40;EMP&#41;"
          ]
        ]
      ]
    ]
    "tieneResumen" => true
    "resumen" => array:2 [
      "es" => array:2 [
        "titulo" => "Resumen"
        "resumen" => "<span id="abst0005" class="elsevierStyleSection elsevierViewall"><p id="spar0030" class="elsevierStyleSimplePara elsevierViewall">Debido a la ocurrencia de un derrame de gasolina en un &#225;rea urbana&#44; los m&#233;todos de Tomograf&#237;a de Resistividad El&#233;ctrica &#40;TRE&#41;&#44; Perfilaje Electromagn&#233;tico &#40;PEM&#41; y de medici&#243;n de Compuestos Org&#225;nicos Vol&#225;tiles &#40;COV&#41; fueron utilizados para definir la pluma de contaminaci&#243;n y dirigir los trabajos de muestreo de suelo&#46; Las anomal&#237;as COV &#40;contaminaci&#243;n reciente&#41; indicaron que una gasolinera localizada en el &#225;rea de estudio es una fuente de contaminaci&#243;n activa&#46; Las zonas con contaminaci&#243;n madura definidas con los m&#233;todos TRE y PEM correspondieron con anomal&#237;as de baja resistividad debido a los procesos de degradaci&#243;n de los hidrocarburos contaminantes&#46; Los resultados alcanzados con los m&#233;todos TRE&#44; PEM y VOC fueron integrados en un mapa&#44; permitiendo la configuraci&#243;n final de las plumas de contaminaci&#243;n y la optimizaci&#243;n de las perforaciones y el muestreo de suelo y producto libre&#46; An&#225;lisis de laboratorio de las muestras de producto libre sugieren la existencia de m&#225;s de un evento de contaminaci&#243;n en el sitio&#44; con la presencia de contaminantes hidrocarburos frescos y degradados&#44; clasificados en el rango de gasolina&#46; Este estudio demuestra las ventajas de la aplicaci&#243;n conjunta de TRE&#44; PEM y COV en sitios con fuentes de contaminaci&#243;n activa&#44; donde se asume la existencia de hidrocarburos contaminantes recientes y maduros en el subsuelo&#46;</p></span>"
      ]
      "en" => array:2 [
        "titulo" => "Abstract"
        "resumen" => "<span id="abst0010" class="elsevierStyleSection elsevierViewall"><p id="spar0035" class="elsevierStyleSimplePara elsevierViewall">As a result of a gasoline spill in an urban area&#44; Electrical Resistivity Tomography &#40;ERT&#41;&#44; Electromagnetic Profiling &#40;EMP&#41; and Volatile Organic Compounds &#40;VOC&#41; methods were used in order to define the contamination plume and to optimize the drilling and soil sampling activities&#46; The VOC anomalies &#40;recent contamination&#41; indicated that a gas station located at the study site is an active contamination source&#46; The mature contaminated zones defined by ERT and EMP methods corresponded with low resistivity anomalies due to degradation process of the hydrocarbons contaminants&#46; The ERT&#44; EMP and VOC results were integrated on a map&#44; allowing the final configuration of contamination plumes and the optimization of drilling and soil&#47;free-product sampling&#46; Laboratory analyses of free-product samples suggest the existence of more than one contamination event in the site&#44; with the presence of recent and degraded-hydrocarbon contaminants classified in the gasoline range&#46; This study shows the advantages of joint application of ERT&#44; EMP and VOC methods in sites with active contamination source&#44; where the existence of recent and mature contaminants in subsoil is assumed&#46;</p></span>"
      ]
    ]
    "multimedia" => array:16 [
      0 => array:7 [
        "identificador" => "f0005"
        "etiqueta" => "Figure 1"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr1.jpeg"
            "Alto" => 1358
            "Ancho" => 1310
            "Tamanyo" => 151869
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0005" class="elsevierStyleSimplePara elsevierViewall">Scheme of the site&#46;</p>"
        ]
      ]
      1 => array:7 [
        "identificador" => "f0010"
        "etiqueta" => "Figure 2"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr2.jpeg"
            "Alto" => 1265
            "Ancho" => 1330
            "Tamanyo" => 148575
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0010" class="elsevierStyleSimplePara elsevierViewall">VOC map&#46; The dark zones indicate the presence of recent hydrocarbon contamination&#46;</p>"
        ]
      ]
      2 => array:7 [
        "identificador" => "f0015"
        "etiqueta" => "Figure 3"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr3.jpeg"
            "Alto" => 1341
            "Ancho" => 1355
            "Tamanyo" => 128426
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0015" class="elsevierStyleSimplePara elsevierViewall">Statistical distribution of ERT data&#46; &#40;H&#41; Mean resistivity curve for the study site&#46; &#40;C&#41; Cloud of low apparent resistivity values separated from mean curve&#46;</p>"
        ]
      ]
      3 => array:7 [
        "identificador" => "f0020"
        "etiqueta" => "Figure 4"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr4.jpeg"
            "Alto" => 1007
            "Ancho" => 1469
            "Tamanyo" => 110105
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0020" class="elsevierStyleSimplePara elsevierViewall">Interpreted resistivity section from ERT profiles with three layers&#46; Low resistivity anomalies in the second layer indicate the presence of mature contamination&#46;</p>"
        ]
      ]
      4 => array:7 [
        "identificador" => "f0025"
        "etiqueta" => "Figure 5"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr5.jpeg"
            "Alto" => 610
            "Ancho" => 1236
            "Tamanyo" => 134643
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0025" class="elsevierStyleSimplePara elsevierViewall">Geoprobe System used to collect soil and ground-water samples</p>"
        ]
      ]
      5 => array:7 [
        "identificador" => "f0030"
        "etiqueta" => "Figure 6"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr6.jpeg"
            "Alto" => 1197
            "Ancho" => 1248
            "Tamanyo" => 139623
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0030" class="elsevierStyleSimplePara elsevierViewall">Experimental results and theoretical dependence of soil resistivity versus pore water salinity for different clay content in soils&#46; Theoretical model&#58; clay porosity<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>55&#37;&#44; sand porosity<span class="elsevierStyleHsp" style=""></span>&#61;<span class="elsevierStyleHsp" style=""></span>25&#37;&#46;</p>"
        ]
      ]
      6 => array:7 [
        "identificador" => "f0035"
        "etiqueta" => "Figure 7"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr7.jpeg"
            "Alto" => 1592
            "Ancho" => 1550
            "Tamanyo" => 211582
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0035" class="elsevierStyleSimplePara elsevierViewall">Resistivity maps&#46; Interpreted resistivity map from ERT for depth&#61;<span class="elsevierStyleHsp" style=""></span>6m&#46; &#40;B&#41; Apparent resistivity map from EMP&#46;</p>"
        ]
      ]
      7 => array:7 [
        "identificador" => "f0040"
        "etiqueta" => "Figure 8"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr8.jpeg"
            "Alto" => 1346
            "Ancho" => 1480
            "Tamanyo" => 181205
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0040" class="elsevierStyleSimplePara elsevierViewall">Integrated data map from indirect methods&#46;</p>"
        ]
      ]
      8 => array:7 [
        "identificador" => "f0045"
        "etiqueta" => "Figure 9"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr9.jpeg"
            "Alto" => 854
            "Ancho" => 1221
            "Tamanyo" => 74157
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0045" class="elsevierStyleSimplePara elsevierViewall">BTEX ratio of free-phase gasoline samples&#46;</p>"
        ]
      ]
      9 => array:7 [
        "identificador" => "f0050"
        "etiqueta" => "Figure 10"
        "tipo" => "MULTIMEDIAFIGURA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "figura" => array:1 [
          0 => array:4 [
            "imagen" => "gr10.jpeg"
            "Alto" => 1001
            "Ancho" => 1263
            "Tamanyo" => 143388
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="sp0050" class="elsevierStyleSimplePara elsevierViewall">Map of hydrocarbons contamination plumes&#46;</p>"
        ]
      ]
      10 => array:7 [
        "identificador" => "tbl0005"
        "etiqueta" => "Table 1"
        "tipo" => "MULTIMEDIATABLA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "tabla" => array:1 [
          "tablatextoimagen" => array:1 [
            0 => array:2 [
              "tabla" => array:1 [
                0 => """
                  <table border="0" frame="\n
                  \t\t\t\t\tvoid\n
                  \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Clean soil sample&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Clay content &#40;&#37;&#41;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Sampling depth &#40;m&#41;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">49&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&#46;6&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">38&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&#46;3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">50&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">4&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">37&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">7&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr></tbody></table>
                  """
              ]
              "imagenFichero" => array:1 [
                0 => "xTab795076.png"
              ]
            ]
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="spar0005" class="elsevierStyleSimplePara elsevierViewall">Clay content and sampling depth values of the clean soil samples&#46; Clay content values were used to define the geoelectric boundary between clean and contaminated soils&#46;</p>"
        ]
      ]
      11 => array:7 [
        "identificador" => "tbl0010"
        "etiqueta" => "Table 2"
        "tipo" => "MULTIMEDIATABLA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "tabla" => array:1 [
          "tablatextoimagen" => array:1 [
            0 => array:2 [
              "tabla" => array:1 [
                0 => """
                  <table border="0" frame="\n
                  \t\t\t\t\tvoid\n
                  \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head  " colspan="2" align="center" valign="top" scope="col" style="border-bottom: 2px solid black">EMP</th><th class="td" title="table-head  " colspan="2" align="center" valign="top" scope="col" style="border-bottom: 2px solid black">ERT</th><th class="td" title="table-head  " colspan="2" align="center" valign="top" scope="col" style="border-bottom: 2px solid black">VOC</th></tr><tr title="table-row"><th class="td" title="table-head  " align="center" valign="top" scope="col"><span class="elsevierStyleBold">&#961; interval &#40;Ohm&#46;m&#41;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col"><span class="elsevierStyleBold">Weight &#40;X</span><span class="elsevierStyleInf"><span class="elsevierStyleBold">ERT</span></span><span class="elsevierStyleBold">&#41;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col"><span class="elsevierStyleBold">&#961; interval &#40;Ohm&#46;m&#41;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col"><span class="elsevierStyleBold">Weight &#40;X</span><span class="elsevierStyleInf"><span class="elsevierStyleBold">EMP</span></span><span class="elsevierStyleBold">&#41;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col"><span class="elsevierStyleBold">VOC interval &#40;ppm&#41;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col"><span class="elsevierStyleBold">Weight &#40;X</span><span class="elsevierStyleInf"><span class="elsevierStyleBold">VOC</span></span><span class="elsevierStyleBold">&#41;</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">&#961;<span class="elsevierStyleInf">a</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>4&#46;3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">&#961;<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>3&#46;2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">VOC<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>20&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">4&#46;3<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span> &#961;<span class="elsevierStyleInf">a</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>5&#46;9&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&#46;2<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>&#961;<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>4&#46;5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">20<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>VOC<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>28&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">5&#46;9<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>&#961;<span class="elsevierStyleInf">a</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>7&#46;5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;5<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>&#961;<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>6&#46;1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">28<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>VOC<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>37&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">7&#46;5<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>&#961;<span class="elsevierStyleInf">a</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>9&#46;5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&#46;1<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>&#961;<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>14&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">37<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>VOC<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>49&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">9&#46;5<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>&#961;<span class="elsevierStyleInf">a</span><span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>13&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">14&#46;0<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>&#961;<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>19&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">49<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>VOC<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>67&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">&#961;<span class="elsevierStyleInf">a</span><span class="elsevierStyleHsp" style=""></span>&#8805;<span class="elsevierStyleHsp" style=""></span>13&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">&#961;<span class="elsevierStyleHsp" style=""></span>&#8805;<span class="elsevierStyleHsp" style=""></span>19&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">67<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>VOC<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>90&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">90<span class="elsevierStyleHsp" style=""></span>&#8804;<span class="elsevierStyleHsp" style=""></span>VOC<span class="elsevierStyleHsp" style=""></span>&#60;<span class="elsevierStyleHsp" style=""></span>120&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">VOC<span class="elsevierStyleHsp" style=""></span>&#8805;<span class="elsevierStyleHsp" style=""></span>120&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">7&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr></tbody></table>
                  """
              ]
              "imagenFichero" => array:1 [
                0 => "xTab795077.png"
              ]
            ]
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="spar0010" class="elsevierStyleSimplePara elsevierViewall">Weight assigned to each value range obtained from application of the EMP&#44; ERT and VOC methods&#46;</p>"
        ]
      ]
      12 => array:7 [
        "identificador" => "tbl0015"
        "etiqueta" => "Table 3"
        "tipo" => "MULTIMEDIATABLA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "tabla" => array:1 [
          "tablatextoimagen" => array:1 [
            0 => array:2 [
              "tabla" => array:1 [
                0 => """
                  <table border="0" frame="\n
                  \t\t\t\t\tvoid\n
                  \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Y&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">EMP data&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">ERT data&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">VOC data&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X<span class="elsevierStyleInf">EMP</span>&#42; MC<span class="elsevierStyleInf">EMP</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X<span class="elsevierStyleInf">ERT</span> &#42; MC<span class="elsevierStyleInf">ERT</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X<span class="elsevierStyleInf">VOC</span>&#42; MC<span class="elsevierStyleInf">VOC</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">N&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">IP&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">580&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">190&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">12&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">7&#46;1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">---&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1&#46;5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">580&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">195&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">10&#46;2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">7&#46;2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1&#46;8&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">580&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">200&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">8&#46;6&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">7&#46;1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">98&#46;9&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">30&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">10&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">580&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">205&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">7&#46;6&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;4&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">170&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">8&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">35&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">14&#46;3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">580&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">210&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">7&#46;6&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">2&#46;8&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">26&#46;8&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">16&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">7&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">580&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">215&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">7&#46;5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">---&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">9&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">8&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr></tbody></table>
                  """
              ]
              "imagenFichero" => array:1 [
                0 => "xTab795075.png"
              ]
            ]
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="spar0015" class="elsevierStyleSimplePara elsevierViewall">Calculation of IP in a portion of the grid around the well S1&#44; where the recent contamination is mainly characterized by high VOC values&#46;</p>"
        ]
      ]
      13 => array:7 [
        "identificador" => "tbl0020"
        "etiqueta" => "Table 4"
        "tipo" => "MULTIMEDIATABLA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "tabla" => array:1 [
          "tablatextoimagen" => array:1 [
            0 => array:2 [
              "tabla" => array:1 [
                0 => """
                  <table border="0" frame="\n
                  \t\t\t\t\tvoid\n
                  \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Y&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">EMP data&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">ERT data&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">VOC data&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X<span class="elsevierStyleInf">EMP</span>&#42; MC<span class="elsevierStyleInf">EMP</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X<span class="elsevierStyleInf">ERT</span> &#42; MC<span class="elsevierStyleInf">ERT</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X<span class="elsevierStyleInf">VOC</span>&#42; MC<span class="elsevierStyleInf">VOC</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">N&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">IP&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">640&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">250&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">8&#46;1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">---&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&#46;5&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">640&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">255&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">8&#46;1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&#46;1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&#46;7&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">12&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">640&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">260&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">8&#46;1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;8&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&#46;9&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">16&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">5&#46;3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">640&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">265&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">8&#46;1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&#46;2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">20&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&#46;7&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">640&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">270&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">8&#46;2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&#46;3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1&#46;2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">20&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&#46;7&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="center" valign="top">640&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">275&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">8&#46;2&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1&#46;1&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">16&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">5&#46;3&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr></tbody></table>
                  """
              ]
              "imagenFichero" => array:1 [
                0 => "xTab795078.png"
              ]
            ]
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="spar0020" class="elsevierStyleSimplePara elsevierViewall">Calculation of IP in a portion of the grid around the spill point&#44; where mature contamination is characterized by low resistivity and VOC values&#46;</p>"
        ]
      ]
      14 => array:7 [
        "identificador" => "tbl0025"
        "etiqueta" => "Table 5"
        "tipo" => "MULTIMEDIATABLA"
        "mostrarFloat" => true
        "mostrarDisplay" => false
        "tabla" => array:1 [
          "tablatextoimagen" => array:1 [
            0 => array:2 [
              "tabla" => array:1 [
                0 => """
                  <table border="0" frame="\n
                  \t\t\t\t\tvoid\n
                  \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="table-head  " align="left" valign="top" scope="col" style="border-bottom: 2px solid black">Well&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">X&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Y&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">LOF &#40;ppm&#41;&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th><th class="td" title="table-head  " align="center" valign="top" scope="col" style="border-bottom: 2px solid black">Sampling Depth&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td" title="table-entry  " align="left" valign="top">S<span class="elsevierStyleInf">1</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">589&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">208&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">678&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">5&#46;50 - 6&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1338&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">9&#46;50 - 10&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">50&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&#46;0 - 2&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">834&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">2&#46;00 - 3&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">306&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&#46;00 - 4&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="left" valign="top">S<span class="elsevierStyleInf">2</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">620&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">267&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">141&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;00 - 5&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">62&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">5&#46;20 - 5&#46;80 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">65&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&#46;00 - 6&#46;30 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">BDL&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&#46;80 - 7&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="left" valign="top">S<span class="elsevierStyleInf">3</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">654&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">281&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">50&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">0&#46;0 - 3&#46;80 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">51&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">6&#46;00 - 7&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">38&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">1&#46;50 a 1&#46;90 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">BDL&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">2&#46;00 - 3&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="left" valign="top">S<span class="elsevierStyleInf">4</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">621&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">245&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">11312&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&#46;00 - 4&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">330&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;00 - 5&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">86&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">5&#46;00 - 6&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">44&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&#46;00 - 4&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="left" valign="top">S<span class="elsevierStyleInf">5</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">630&#46;9&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">253&#46;8&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">55&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;00 - 5&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">33&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">5&#46;00 - 6&#46;80 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">2071&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">3&#46;15 - 4&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="left" valign="top">S<span class="elsevierStyleInf">x</span>&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">616&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">294&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">301&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;00 - 4&#46;40 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr><tr title="table-row"><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="" valign="top">&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">279&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td><td class="td" title="table-entry  " align="center" valign="top">4&#46;40 - 5&#46;00 m&nbsp;\t\t\t\t\t\t\n
                  \t\t\t\t</td></tr></tbody></table>
                  """
              ]
              "imagenFichero" => array:1 [
                0 => "xTab795074.png"
              ]
            ]
          ]
        ]
        "descripcion" => array:1 [
          "es" => "<p id="spar0025" class="elsevierStyleSimplePara elsevierViewall">Soil LOF concentration and sampling depth values&#46; Grey rows show the maximal LOF concentrations for each well&#46;</p>"
        ]
      ]
      15 => array:6 [
        "identificador" => "eq0005"
        "etiqueta" => "&#40;1&#41;"
        "tipo" => "MULTIMEDIAFORMULA"
        "mostrarFloat" => false
        "mostrarDisplay" => true
        "Formula" => array:5 [
          "Matematica" => "IPj&#61;&#8721;i&#61;1Nj&#40;Xij&#42;MCi&#41;"
          "Fichero" => "si1.jpeg"
          "Tamanyo" => 1633
          "Alto" => 21
          "Ancho" => 160
        ]
      ]
    ]
    "bibliografia" => array:2 [
      "titulo" => "Bibliography"
      "seccion" => array:1 [
        0 => array:2 [
          "identificador" => "bibs0005"
          "bibliografiaReferencia" => array:38 [
            0 => array:3 [
              "identificador" => "bib0005"
              "etiqueta" => "Abdel Aal et al&#46;&#44; 2004"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Effects of microbial processes on electrolytic and interfacial electrical properties of unconsolidated sediments"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "G&#46;Z&#46; Abdel Aal"
                            1 => "E&#46; Atekwana"
                            2 => "L&#46;D&#46; Slater"
                            3 => "E&#46;A&#46; Atekwana"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "Geophys&#46; Res&#46; Lett"
                        "fecha" => "2004"
                        "volumen" => "31"
                        "numero" => "12"
                        "paginaInicial" => "1"
                        "paginaFinal" => "4"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            1 => array:3 [
              "identificador" => "bib0010"
              "etiqueta" => "API&#44; 1991"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "An evaluation of soil gas and geophysical techniques for detection of hydrocarbons"
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "API"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:4 [
                        "titulo" => "API Publication N&#186; 4509&#44; Washington&#44; D&#46;C&#46;"
                        "fecha" => "1991"
                        "editorial" => "Health and Environmental Sciences Department&#44; American Petroleum Institute"
                        "editorialLocalizacion" => "USA"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            2 => array:3 [
              "identificador" => "bib0015"
              "etiqueta" => "Arpel&#44; 1992"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Regional association of oil&#44; gas and biofuels sector companies in Latin America and the Caribbean"
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "Arpel"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:3 [
                        "fecha" => "1992"
                        "editorial" => "Guide to solid waste management oil refinery"
                        "editorialLocalizacion" => "Canada"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            3 => array:3 [
              "identificador" => "bib0020"
              "etiqueta" => "Atekwana et al&#46;&#44; 2001"
              "referencia" => array:1 [
                0 => array:1 [
                  "referenciaCompleta" => "Atekwana E&#46;&#44; Cassidy D&#46;P&#46;&#44; Magnuson C&#46; Endres&#44; Werkema A&#46;L&#46;&#44; D&#46;D&#46; Jr&#46;&#44; Sauck W&#46;A&#46;&#44; 2001&#44; Changes in geoelectrical properties accompanying microbial degradation of LNAPL&#46; In Proceedings of the Symposium on the Application of Geophysics to Engineering and Environmental Problems&#44; Denver&#44; Colorado&#44; USA&#46;"
                ]
              ]
            ]
            4 => array:3 [
              "identificador" => "bib0025"
              "etiqueta" => "Briggs&#44; 1974"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Machine contouring using minimum curvature"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "I&#46;C&#46; Briggs"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "tituloSerie" => "Geophysics"
                        "fecha" => "1974"
                        "volumen" => "39"
                        "paginaInicial" => "39"
                        "paginaFinal" => "48"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            5 => array:3 [
              "identificador" => "bib0030"
              "etiqueta" => "Delgado-Rodr&#237;guez et al&#46;&#44; 2006"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Geoelectrical characterization of a site with hydrocarbon contamination caused by pipeline leakage"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "O&#46; Delgado-Rodr&#237;guez"
                            1 => "V&#46; Shevnin"
                            2 => "J&#46; OchoaVald&#233;s"
                            3 => "A&#46; Ryjov"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "Geof&#237;sica Internacional"
                        "fecha" => "2006"
                        "volumen" => "45"
                        "numero" => "1"
                        "paginaInicial" => "63"
                        "paginaFinal" => "72"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            6 => array:3 [
              "identificador" => "bib0035"
              "etiqueta" => "Delgado-Rodr&#237;guez et al&#46;&#44; 2006a"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Using electrical techniques for planning the remediation process in a hydrocarbon contaminated site"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "O&#46; Delgado-Rodr&#237;guez"
                            1 => "V&#46; Shevnin"
                            2 => "J&#46; OchoaVald&#233;s"
                            3 => "A&#46; Ryjov"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "Rev&#46; Int&#46; Contam&#46; Ambient"
                        "fecha" => "2006"
                        "volumen" => "22"
                        "numero" => "4"
                        "paginaInicial" => "157"
                        "paginaFinal" => "163"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            7 => array:3 [
              "identificador" => "bib0040"
              "etiqueta" => "Delgado-Rodr&#237;guez et al&#46;&#44; 2012"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Estimation of soil petrophysical parameters based on electrical resistivity values obtained from lab and in-field measurements"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "O&#46; Delgado-Rodr&#237;guez"
                            1 => "M&#46; Ladr&#243;n de GuevaraTorres"
                            2 => "V&#46; Shevnin"
                            3 => "A&#46; Ryjov"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "Geof&#237;sica Internacional"
                        "fecha" => "2012"
                        "volumen" => "51"
                        "numero" => "1"
                        "paginaInicial" => "5"
                        "paginaFinal" => "15"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            8 => array:3 [
              "identificador" => "bib0045"
              "etiqueta" => "EEA&#44; 2010"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:1 [
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "EEA"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:2 [
                        "titulo" => "Benzene&#44; toluene&#44; ethylbenzene&#44; xylene &#40;as BTEX&#41;&#58; European Environment Agency"
                        "fecha" => "2010"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            9 => array:3 [
              "identificador" => "bib0050"
              "etiqueta" => "Fischer et al&#46;&#44; 1996"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Factors affecting indoor air concentrations of volatile organic compounds at a site of subsurface gasoline contamination"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:6 [
                            0 => "M&#46; Fischer"
                            1 => "A&#46; Bentley"
                            2 => "K&#46; Dunkin"
                            3 => "A&#46; Hodgson"
                            4 => "W&#46; Nazaroff"
                            5 => "J&#46;D&#46; Sextro"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "tituloSerie" => "Environ&#46; Sci&#46; Technol"
                        "fecha" => "1996"
                        "volumen" => "30"
                        "paginaInicial" => "2948"
                        "paginaFinal" => "2957"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            10 => array:3 [
              "identificador" => "bib0055"
              "etiqueta" => "Geonics Limited&#44; 2010"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:1 [
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "Geonics Limited"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:3 [
                        "titulo" => "EM31-MK2&#44; Operating Manual"
                        "fecha" => "2010"
                        "paginaInicial" => "51"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            11 => array:3 [
              "identificador" => "bib0060"
              "etiqueta" => "Golden Software Inc&#46;&#44; 2002"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Surfer&#46; User&#180;s Guide"
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "Golden Software Inc&#46;"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:3 [
                        "titulo" => "Contouring and 3D mapping for Scientists and Engineers"
                        "fecha" => "2002"
                        "paginaInicial" => "640"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            12 => array:3 [
              "identificador" => "bib0065"
              "etiqueta" => "IMP&#44; 2006"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Proyecto F&#46;21320 &#8220;Caracterizaci&#243;n de la contaminaci&#243;n de suelos y agua fre&#225;tica en once diferentes sitios del D&#46;D&#46;V&#46; Minatitl&#225;n &#8211; Villahermosa y D&#46;D&#46;V&#46; Minatitl&#225;n &#8211; M&#233;xico&#8221;"
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "IMP"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:3 [
                        "titulo" => "Direcci&#243;n de Seguridad y Medio Ambiente"
                        "fecha" => "2006"
                        "editorial" => "Instituto Mexicano del Petr&#243;leo"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            13 => array:3 [
              "identificador" => "bib0070"
              "etiqueta" => "IMP&#44; 2006a"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Proyecto F&#46;21399 &#8220;Apoyo para la caracterizaci&#243;n y restauraci&#243;n del &#225;rea norte de la ex - Refiner&#237;a 18 de Marzo&#8221;"
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "IMP"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:3 [
                        "titulo" => "Direcci&#243;n de Seguridad y Medio Ambiente"
                        "fecha" => "2006"
                        "editorial" => "Instituto Mexicano del Petr&#243;leo"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            14 => array:3 [
              "identificador" => "bib0075"
              "etiqueta" => "IMP&#44; 2008"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Proyecto F&#46;21472 &#8220;Evaluaci&#243;n del estado actual de la contaminaci&#243;n por hidrocarburos en el suelo y agua subterr&#225;nea de la TAD de Azcapotzalco&#8221;"
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "IMP"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:3 [
                        "titulo" => "Direcci&#243;n de Seguridad y Medio Ambiente"
                        "fecha" => "2008"
                        "editorial" => "Instituto Mexicano del Petr&#243;leo"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            15 => array:3 [
              "identificador" => "bib0080"
              "etiqueta" => "IMP&#44; 2013"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Proyecto F&#46;23487 &#8220;Estudio de la contaminaci&#243;n por hidrocarburos en suelo y subsuelo del &#225;rea de reconfiguraci&#243;n &#40;CADI&#41; de la Refiner&#237;a Ing&#46; Antonio M&#46; Amor de Salamanca&#44; Gto&#46;&#8221;"
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "IMP"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:2 [
                        "titulo" => "Direcci&#243;n de Seguridad y Medio Ambiente&#44; Instituto Mexicano del Petr&#243;leo"
                        "fecha" => "2013"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            16 => array:3 [
              "identificador" => "bib0085"
              "etiqueta" => "Keller and Frischknecht&#44; 1966"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:1 [
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "G&#46;V&#46; Keller"
                            1 => "F&#46;C&#46; Frischknecht"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:5 [
                        "titulo" => "Electrical methods in geophysical prospecting"
                        "fecha" => "1966"
                        "paginaInicial" => "517"
                        "editorial" => "Pergamon Press"
                        "editorialLocalizacion" => "Oxford"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            17 => array:3 [
              "identificador" => "bib0090"
              "etiqueta" => "Korhonen et al&#46;&#44; 2005"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Interpretation of lineaments from airborne geophysical and topographic data&#46; An alternative model within version Laxemar 1&#46;2 of the Oskarshamn modelling project"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "K&#46; Korhonen"
                            1 => "A&#46; Kuivam&#228;ki"
                            2 => "T&#46; Ruotoistenm&#228;ki"
                            3 => "M&#46; Paananen"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:3 [
                        "titulo" => "Geological Survey of Finland"
                        "fecha" => "2005"
                        "paginaInicial" => "39"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            18 => array:3 [
              "identificador" => "bib0095"
              "etiqueta" => "Lin and Chou&#44; 2006"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Henry&#8217;s law constant variations of volatile organic compounds in wastewater and activated sludge"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "J&#46;H&#46; Lin"
                            1 => "M&#46;S&#46; Chou"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "Aerosol and Air Quality Research"
                        "fecha" => "2006"
                        "volumen" => "6"
                        "numero" => "2"
                        "paginaInicial" => "180"
                        "paginaFinal" => "192"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            19 => array:3 [
              "identificador" => "bib0100"
              "etiqueta" => "Loke and Barker&#44; 1996"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Rapid least-squares inversion of apparent resistivity pseudosections by a quasi-Newton method"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "M&#46;H&#46; Loke"
                            1 => "R&#46;D&#46; Barker"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "tituloSerie" => "Geophys&#46; Prospect"
                        "fecha" => "1996"
                        "volumen" => "44"
                        "paginaInicial" => "131"
                        "paginaFinal" => "152"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            20 => array:3 [
              "identificador" => "bib0105"
              "etiqueta" => "Loke&#44; 2013"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:1 [
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "M&#46;H&#46; Loke"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:3 [
                        "titulo" => "Tutorial&#58; 2-D and 3-D electrical imaging surveys"
                        "fecha" => "2013"
                        "paginaInicial" => "162"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            21 => array:3 [
              "identificador" => "bib0110"
              "etiqueta" => "Mar&#237;n-C&#243;rdova et al&#46;&#44; 1986"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:1 [
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "S&#46; Mar&#237;n-C&#243;rdova"
                            1 => "C&#46;J&#46; Aguayo"
                            2 => "A&#46;R&#46; Hu&#237;zar"
                            3 => "V&#46;J&#46; Mandujano"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:4 [
                        "titulo" => "Geolog&#237;a en el Valle de M&#233;xico con fines geohidrol&#243;gicos"
                        "fecha" => "1986"
                        "editorial" => "Instituto de Geolog&#237;a"
                        "editorialLocalizacion" => "UNAM y CAVM"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            22 => array:3 [
              "identificador" => "bib0115"
              "etiqueta" => "M&#233;ndez-Velarde et al&#46;&#44; 2012"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Dise&#241;o de un plan de muestreo optimizado para la caracterizaci&#243;n de hidrocarburos en suelos"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:3 [
                            0 => "S&#46;F&#46; M&#233;ndez-Velarde"
                            1 => "J&#46; Ochoa-Vald&#233;s"
                            2 => "O&#46; Delgado-Rodr&#237;guez"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:4 [
                        "titulo" => "Caso de estudio &#40;48&#46;6 hect&#225;reas&#41;&#46; SMA5&#44; XVIII Foro de Avances de la Industria de la Refinaci&#243;n"
                        "fecha" => "2012"
                        "editorial" => "Instituto Mexicano del Petr&#243;leo"
                        "editorialLocalizacion" => "M&#233;xico DF"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            23 => array:3 [
              "identificador" => "bib0120"
              "etiqueta" => "Modin et al&#46;&#44; 1997"
              "referencia" => array:1 [
                0 => array:1 [
                  "referenciaCompleta" => "Modin I&#46;N&#46;&#44; Shevnin V&#46;A&#46;&#44; Bobatchev A&#46;A&#46;&#44; Bolshakov D&#46;K&#46; Leonov D&#46;A&#46;&#44; Vladov M&#46;L&#46;&#44; 1997&#44; Investigations of oil pollution with electrical prospecting methods&#46; In&#58; Proceedings of the 3rd EEGS-ES Meeting&#44; Aarhus&#44; Denmark&#44; 267-270&#46;"
                ]
              ]
            ]
            24 => array:3 [
              "identificador" => "bib0125"
              "etiqueta" => "Ochoa et al&#46;&#44; 2007"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Aplicaci&#243;n del an&#225;lisis de vapores org&#225;nicos del subsuelo &#40;gasometr&#237;as&#41; en la caracterizaci&#243;n de sitios contaminados por hidrocarburos"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:3 [
                            0 => "J&#46; Ochoa"
                            1 => "S&#46; M&#233;ndez"
                            2 => "C&#46; Vald&#233;s"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:2 [
                        "titulo" => "Derecho de Autor No&#46; 03-2007-061912264100-01&#44; Instituto Mexicano del Petr&#243;leo"
                        "fecha" => "2007"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            25 => array:3 [
              "identificador" => "bib0130"
              "etiqueta" => "Ochoa et al&#46;&#44; 2002"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Evaluaci&#243;n de la contaminaci&#243;n por hidrocarburos del subsuelo &#40;gasometr&#237;as&#41;"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:3 [
                            0 => "J&#46; Ochoa"
                            1 => "S&#46; M&#233;ndez"
                            2 => "A&#46; Rosas"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "El Petr&#243;leo de M&#233;xico"
                        "fecha" => "2002"
                        "volumen" => "III"
                        "numero" => "2"
                        "paginaInicial" => "42"
                        "paginaFinal" => "54"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            26 => array:3 [
              "identificador" => "bib0135"
              "etiqueta" => "Osella et al&#46;&#44; 2002"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Characterization of a contaminant plume due to a hydrocarbon spill using geoelectrical methods"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:3 [
                            0 => "A&#46; Osella"
                            1 => "M&#46; De la Vega"
                            2 => "E&#46; Lascano"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "tituloSerie" => "J Environ&#46; Eng&#46; Geophysics"
                        "fecha" => "2002"
                        "volumen" => "7"
                        "paginaInicial" => "78"
                        "paginaFinal" => "87"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            27 => array:3 [
              "identificador" => "bib0140"
              "etiqueta" => "Ontario Geological Survey&#44; 2003"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Ontario airborne geophysical surveys&#44; magnetic data&#44; Oba-Kapuskasing area"
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "Ontario Geological Survey"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:3 [
                        "titulo" => "Geophysical Data Set 1024 &#8211; Revised"
                        "fecha" => "2003"
                        "paginaInicial" => "67"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            28 => array:3 [
              "identificador" => "bib0145"
              "etiqueta" => "Orfanos and Apostolopoulos&#44; 2012"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Analysis of different geophysical methods in the detection of an underground opening at a controlled test site"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:2 [
                            0 => "C&#46; Orfanos"
                            1 => "G&#46; Apostolopoulos"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "Journal of the Balkan Geophysical Society"
                        "fecha" => "2012"
                        "volumen" => "15"
                        "numero" => "1"
                        "paginaInicial" => "7"
                        "paginaFinal" => "18"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            29 => array:3 [
              "identificador" => "bib0150"
              "etiqueta" => "Ryjov and Shevnin&#44; 2002"
              "referencia" => array:1 [
                0 => array:1 [
                  "referenciaCompleta" => "Ryjov A&#46;&#44; Shevnin V&#46;&#44; 2002&#44; Theoretical calculation of rocks electrical resistivity and some examples of algorithm&#8217;s application&#46; In Proceedings of the Symposium on the Application of Geophysics to Engineering and Environmental Problems &#40;SAGEEP&#41;&#44; Las Vegas&#44; Nevada&#44; USA&#46;"
                ]
              ]
            ]
            30 => array:3 [
              "identificador" => "bib0155"
              "etiqueta" => "Sauck&#44; 2000"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "A model for the resistivity structure of LNAPL plumes and their environs in sandy sediments"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "W&#46;A&#46; Sauck"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "tituloSerie" => "J&#46; App&#46; Geophys"
                        "fecha" => "2000"
                        "volumen" => "44"
                        "paginaInicial" => "151"
                        "paginaFinal" => "165"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            31 => array:3 [
              "identificador" => "bib0160"
              "etiqueta" => "SEMARNAT&#44; 2005"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Norma Oficial Mexicana NOM-138-SEMARNAT&#47;SS-2003&#44; L&#237;mites m&#225;ximos permisibles de contaminaci&#243;n en suelos por hidrocarburos y las especificaciones para su caracterizaci&#243;n y remediaci&#243;n"
                      "autores" => array:1 [
                        0 => array:2 [
                          "colaboracion" => "SEMARNAT"
                          "etal" => false
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:2 [
                        "titulo" => "Diario Oficial de la Federaci&#243;n"
                        "fecha" => "2005"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            32 => array:3 [
              "identificador" => "bib0165"
              "etiqueta" => "Shevnin et al&#46;&#44; 2005"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Geoelectrical characterization of an oil contaminated site in Tabasco&#44; Mexico"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:6 [
                            0 => "V&#46; Shevnin"
                            1 => "O&#46; Delgado-Rodr&#237;guez"
                            2 => "L&#46; Fern&#225;ndezLinares"
                            3 => "H&#46; Zegarra-Martinez"
                            4 => "A&#46; Mousatov"
                            5 => "A&#46;A&#46; Ryjov"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "Geof&#237;sica Internacional"
                        "fecha" => "2005"
                        "volumen" => "44"
                        "numero" => "3"
                        "paginaInicial" => "251"
                        "paginaFinal" => "263"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            33 => array:3 [
              "identificador" => "bib0170"
              "etiqueta" => "Shevnin et al&#46;&#44; 2006"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Estimation of soil petrophysical parameters from resistivity data&#58; Application to oil-contaminated site characterization"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:6 [
                            0 => "V&#46; Shevnin"
                            1 => "O&#46; Delgado-Rodr&#237;guez"
                            2 => "A&#46; Mousatov"
                            3 => "D&#46; Flores-Hern&#225;ndez"
                            4 => "H&#46; Zegarra-Martinez"
                            5 => "A&#46;A&#46; Ryjov"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:6 [
                        "tituloSerie" => "Geof&#237;sica Internacional"
                        "fecha" => "2006"
                        "volumen" => "45"
                        "numero" => "3"
                        "paginaInicial" => "179"
                        "paginaFinal" => "193"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            34 => array:3 [
              "identificador" => "bib0175"
              "etiqueta" => "Shevnin et al&#46;&#44; 2007"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Estimation of clay content in soil based on resistivity modeling and laboratory measurements"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "V&#46; Shevnin"
                            1 => "A&#46; Mousatov"
                            2 => "A&#46;A&#46; Ryjov"
                            3 => "O&#46; DelgadoRodr&#237;guez"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "tituloSerie" => "Geophy&#46; Prosp"
                        "fecha" => "2007"
                        "volumen" => "55"
                        "paginaInicial" => "265"
                        "paginaFinal" => "275"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            35 => array:3 [
              "identificador" => "bib0180"
              "etiqueta" => "Siemon&#44; 2009"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Levelling of helicopter-borne frequency-domain electromagnetic data"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "B&#46; Siemon"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Revista" => array:5 [
                        "tituloSerie" => "Journal of Applied Geophysics"
                        "fecha" => "2009"
                        "volumen" => "67"
                        "paginaInicial" => "206"
                        "paginaFinal" => "218"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            36 => array:3 [
              "identificador" => "bib0185"
              "etiqueta" => "Stout et al&#46;&#44; 2002"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Chemical Fingerprinting of Hydrocarbons"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:4 [
                            0 => "S&#46;A&#46; Stout"
                            1 => "A&#46;D&#46; Uhler"
                            2 => "K&#46;J&#46; McCarthy"
                            3 => "Emsbo Mattingly"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:6 [
                        "titulo" => "Introduction to environmental forensics"
                        "fecha" => "2002"
                        "paginaInicial" => "137"
                        "paginaFinal" => "260"
                        "editorial" => "Academic Press"
                        "editorialLocalizacion" => "San Diego&#44; California"
                      ]
                    ]
                  ]
                ]
              ]
            ]
            37 => array:3 [
              "identificador" => "bib0190"
              "etiqueta" => "Vanhala&#44; 1997"
              "referencia" => array:1 [
                0 => array:2 [
                  "contribucion" => array:1 [
                    0 => array:2 [
                      "titulo" => "Laboratory and field studies of environmental and exploration applications of the spectral induced-polarization &#40;SIP&#41; method"
                      "autores" => array:1 [
                        0 => array:2 [
                          "etal" => false
                          "autores" => array:1 [
                            0 => "H&#46; Vanhala"
                          ]
                        ]
                      ]
                    ]
                  ]
                  "host" => array:1 [
                    0 => array:1 [
                      "Libro" => array:3 [
                        "titulo" => "Academic dissertation&#44; for the degree of Doctor of Technology"
                        "fecha" => "1997"
                        "editorial" => "Helsinki University of Technology"
                      ]
                    ]
                  ]
                ]
              ]
            ]
          ]
        ]
      ]
    ]
  ]
  "idiomaDefecto" => "es"
  "url" => "/00167169/0000005300000002/v2_201505081358/S0016716914714990/v2_201505081358/es/main.assets"
  "Apartado" => array:4 [
    "identificador" => "36047"
    "tipo" => "SECCION"
    "es" => array:2 [
      "titulo" => "Original paper"
      "idiomaDefecto" => true
    ]
    "idiomaDefecto" => "es"
  ]
  "PDF" => "https://static.elsevier.es/multimedia/00167169/0000005300000002/v2_201505081358/S0016716914714990/v2_201505081358/es/main.pdf?idApp=UINPBA00004N&text.app=https://www.elsevier.es/"
  "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S0016716914714990?idApp=UINPBA00004N"
]

Información del artículo

ISSN: 00167169
Idioma original: Español

DOI:10.1016/S0016-7169(14)71499-0

Datos actualizados diariamente

año/Mes	Html	Pdf	Total

2024 Noviembre	3	0	3
2024 Octubre	20	4	24
2024 Septiembre	16	6	22
2024 Agosto	24	1	25
2024 Julio	17	2	19
2024 Junio	20	5	25
2024 Mayo	15	8	23
2024 Abril	16	22	38
2024 Marzo	26	9	35
2024 Febrero	25	11	36
2024 Enero	24	14	38
2023 Diciembre	28	5	33
2023 Noviembre	24	8	32
2023 Octubre	31	14	45
2023 Septiembre	18	1	19
2023 Agosto	22	10	32
2023 Julio	15	3	18
2023 Junio	18	14	32
2023 Mayo	25	9	34
2023 Abril	18	7	25
2023 Marzo	20	5	25
2023 Febrero	12	4	16
2023 Enero	22	3	25
2022 Diciembre	23	5	28
2022 Noviembre	23	11	34
2022 Octubre	20	19	39
2022 Septiembre	26	22	48
2022 Agosto	25	15	40
2022 Julio	28	10	38
2022 Junio	38	7	45
2022 Mayo	26	8	34
2022 Abril	35	8	43
2022 Marzo	52	6	58
2022 Febrero	40	5	45
2022 Enero	49	5	54
2021 Diciembre	31	7	38
2021 Noviembre	26	12	38
2021 Octubre	29	23	52
2021 Septiembre	20	11	31
2021 Agosto	27	10	37
2021 Julio	30	13	43
2021 Junio	38	9	47
2021 Mayo	16	9	25
2021 Abril	32	17	49
2021 Marzo	22	13	35
2021 Febrero	9	7	16
2021 Enero	20	12	32
2020 Diciembre	8	4	12
2020 Noviembre	13	7	20
2020 Octubre	11	11	22
2020 Septiembre	8	11	19
2020 Agosto	6	8	14
2020 Julio	15	3	18
2020 Junio	9	3	12
2020 Mayo	12	3	15
2020 Abril	18	6	24
2020 Marzo	10	4	14
2020 Febrero	15	5	20
2020 Enero	9	3	12
2019 Diciembre	13	9	22
2019 Noviembre	18	6	24
2019 Octubre	13	8	21
2019 Septiembre	19	5	24
2019 Agosto	13	0	13
2019 Julio	12	17	29
2019 Junio	21	25	46
2019 Mayo	63	60	123
2019 Abril	44	23	67
2019 Marzo	15	7	22
2019 Febrero	15	6	21
2019 Enero	10	6	16
2018 Diciembre	4	3	7
2018 Noviembre	2	4	6
2018 Octubre	10	7	17
2018 Septiembre	24	1	25
2018 Agosto	8	13	21
2018 Julio	4	3	7
2018 Junio	8	1	9
2018 Mayo	10	7	17
2018 Abril	5	20	25
2018 Marzo	5	0	5
2018 Febrero	6	3	9
2018 Enero	3	0	3
2017 Diciembre	9	1	10
2017 Noviembre	8	1	9
2017 Octubre	13	2	15
2017 Septiembre	6	6	12
2017 Agosto	11	4	15
2017 Julio	13	1	14
2017 Junio	94	5	99
2017 Mayo	21	2	23
2017 Abril	16	0	16
2017 Marzo	21	52	73
2017 Febrero	12	5	17
2017 Enero	17	0	17
2016 Diciembre	29	8	37
2016 Noviembre	32	6	38
2016 Octubre	29	13	42
2016 Septiembre	36	2	38
2016 Agosto	12	2	14
2016 Julio	15	1	16
2016 Junio	20	10	30
2016 Mayo	13	2	15
2016 Abril	14	3	17
2016 Marzo	14	4	18
2016 Febrero	10	8	18
2016 Enero	17	8	25
2015 Diciembre	14	2	16
2015 Noviembre	9	3	12
2015 Octubre	15	3	18
2015 Septiembre	19	5	24
2015 Agosto	5	3	8
2015 Julio	8	2	10
2015 Junio	5	0	5
2015 Mayo	10	1	11
2015 Abril	3	3	6
2015 Marzo	4	0	4

Mostrar todo

Indexada en:

Síguenos:

Estadísticas

Indexada en:

Síguenos:

Estadísticas

Suscríbase a la newsletter