Predicting spatial distribution of heavy metals in agricultural soils using electrical resistivity tomography technique 2D-ERT

2020 ◽  
Author(s):  
Nesrine Chaali ◽  
Daniel Bravo ◽  
Sofiane Ouazaa ◽  
Jose Isidro Beltrán Medina ◽  
Javier Benavides
Keyword(s):  
Heavy Metals ◽  
Electrical Resistivity ◽  
Spatial Distribution ◽  
Pearson Correlation ◽  
Chemical Properties ◽  
Soil Chemical Properties ◽  
Resistivity Tomography ◽  
Resistivity Measurements ◽  
Geophysical Techniques ◽  
Cd Distribution

<p>Increasing consideration is being placed on the environmental impact of soil contamination with heavy metals (HM), especially in productive agricultural areas. So, a key task is to characterize this contamination qualitatively and quantitatively in order to understand the spatial distribution of HM and decide about the adequate management. Traditional sampling to monitor HM distribution is time, cost-consuming and often unrepresentative. Additionally, sparse and punctual data measurements may not allow understanding the real dynamic of HM in the soil profile, and in many cases the collected data fails in providing the needed information. Recently, in-situ geophysical techniques based on electrical resistivity tomography measurements (ERT) were implemented in agriculture as a “proxy” to determine spatial and temporal distribution of HM. The objective of this study was to provide an accurate information for future efficient measures of soil remediation, by understanding the HM distribution, specifically cadmium (Cd) and arsenic (As), using electrical resistivity measurements combined with soil chemical analyses. A UNI-T UT523A devise was used in a “Wenner Alpha” configuration to perform ERT survey at 2 m depth in nine locations of Tolima department-Colombia. 2D-ERT cross sections “Tomograms” were obtained by the Res2Dinv software which allowed characterizing qualitatively the spatial distribution of Cd and As. Chemical concentration values for both Cd (0.36±0.06 mg.kg<sup>-1</sup>) and As (3.00±0.28 mg.kg<sup>-1</sup>) were introduced in the inverse modelling procedure as a solution to provide an easier and reliable alternative to determine the shape, size, and path of the likely electrical resistivity distribution of the studied HM. Tomograms revealed that Cd distribution was mainly observed in deeper soil profile (0.80 m), while As was observed basically in shallower soil layers (0.45 m). Higher electrical resistivity values (330–48000 Ω m) correspond to Cd distribution and lower electrical resistivity values (138-291 Ω m) are related to As distribution. A high positive Pearson correlation (ρ) between electrical resistivity measurements and soil chemical properties (for Cd and As content) was obtained for the nine locations; ρ values of 0.97 and 0.98 were obtained for Cd and As; respectively. A linear regression was performed between ERT measurements and Cd and As contents; (R<sup>2</sup>=0.94, RMSE=0.33) and (R<sup>2</sup>=0.97 RMSE=0.18) for Cd and As; respectively. The results underlie the utility of the combined geophysical techniques, based on electrical resistivity measurements, and soil chemical properties to improve the understanding of HM dynamic.</p><p><strong>Key words</strong>: Geophysical techniques, tomograms, heavy metals, soil chemical properties, spatial distribution, Pearson correlation.</p>

Pore-Scale Joint Evaluation of Dielectric Permittivity and Electrical Resistivity for Assessment of Hydrocarbon Saturation Using Numerical Simulations

SPE Journal ◽  
2016 ◽  
Vol 21 (06) ◽  
pp. 1930-1942 ◽  
Author(s):  
Huangye Chen ◽  
Zoya Heidari
Keyword(s):  
Electrical Resistivity ◽  
Spatial Distribution ◽  
Dielectric Permittivity ◽  
Pore Structure ◽  
Maximum Error ◽  
New Method ◽  
Pore Scale ◽  
Resistivity Measurements ◽  
Hydrocarbon Saturation ◽  
Permittivity Measurements

Summary Complex pore geometry and composition, as well as anisotropic behavior and heterogeneity, can affect physical properties of rocks such as electrical resistivity and dielectric permittivity. The aforementioned physical properties are used to estimate in-situ petrophysical properties of the formation such as hydrocarbon saturation. In the application of conventional methods for interpretation of electrical-resistivity (e.g., Archie's equation and the dual-water model) and dielectric-permittivity measurements [e.g., complex refractive index model (CRIM)], the impacts of complex pore structure (e.g., kerogen porosity and intergranular pores), pyrite, and conductive mature kerogen have not been taken into account. These limitations cause significant uncertainty in estimates of water saturation. In this paper, we introduce a new method that combines interpretation of dielectric-permittivity and electrical-resistivity measurements to improve assessment of hydrocarbon saturation. The combined interpretation of dielectric-permittivity and electrical-resistivity measurements enables assimilating spatial distribution of rock components (e.g., pore, kerogen, and pyrite networks) in conventional models. We start with pore-scale numerical simulations of electrical resistivity and dielectric permittivity of fluid-bearing porous media to investigate the structure of pore and matrix constituents in these measurements. The inputs to these simulators are 3D pore-scale images. We then introduce an analytical model that combines resistivity and permittivity measurements to assess water-filled porosity and hydrocarbon saturation. We apply the new method to actual digital sandstones and synthetic digital organic-rich mudrock samples. The relative errors (compared with actual values estimated from image processing) in the estimate of water-filled porosity through our new method are all within the 10% range. In the case of digital sandstone samples, CRIM provided reasonable estimates of water-filled porosity, with only four out of twenty-one estimates beyond 10% relative error, with the maximum error of 30%. However, in the case of synthetic digital organic-rich mudrocks, six out of ten estimates for water-filled porosity were beyond 10% with CRIM, with the maximum error of 40%. Therefore, the improvement was more significant in the case of organic-rich mudrocks with complex pore structure. In the case of synthetic digital organic-rich mudrock samples, our simulation results confirm that not only the pore structure but also spatial distribution and tortuosity of water, kerogen, and pyrite networks affect the measurements of dielectric permittivity and electrical resistivity. Taking into account these parameters through the joint interpretation of dielectric-permittivity and electrical-resistivity measurements significantly improves assessment of hydrocarbon saturation.

scholarly journals IDENTIFICATION AND EVALUATION OF FRACTURES USING ELECTRICAL RESISTIVITY TOMOGRAPHY IN THE VICINITY OF THE AXIS OF THE HUAMANTANGA DAM – LIMA – PERU

2018 ◽  
Vol 36 (2) ◽  
pp. 111
Author(s):  
Christ Jesus Barriga Paria ◽  
Jorge Pantaleon Barriga Gamarra
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
The Other ◽  
Management Technique ◽  
Geophysical Investigation ◽  
Electrical Method ◽  
Resistivity Tomography ◽  
Outer Slope ◽  
Resistivity Measurements ◽  
High Infiltration

ABSTRACT. Huamantanga located approximately 3390 msnm in the central highlands of Peru, a district that promotes the sowing and harvesting of water called “mamanteo”, Inca ancestral water management technique to derive water from a ravine during the rainy season, to places with a high infiltration. On the other hand the construction of a dam, named with the same name, was built for the storage water due to the increase of the agrarian activities, nevertheless worrisome leaks were observed by which electrical resistivity tomography in these possible zones were realized Distributed four profiles, one parallel to the axis of the dam, 10 to 15 meters upstream of the first profile, on the outer slope and the fourth profile approximately 10 meters above the spring. In this way, the resistivity measurements were performed for each of the four lines of Tomographic Electric, in order to obtain detailed information of the stratigraphy in the study area and to identify the georesistive anomalies caused by tectonic or geological faults, Reflect as areas of low resistivities or anomalies. Analyzed the area of study were found considerable local fractures which were recommended to be quickly waterproofed because the risk of infiltrations is latent. Keywords: infiltration, fracture, geophysical investigation, electrical method.    RESUMO. Huamantanga localizado aproximadamente a 3390 msnm no centro da serra do Peru, distrito que promove o cultivo e colheita de água chamado de “mamanteo”, atividade incaica para derivar um fluxo de água durante a estação chuvosa, para locais com alta infiltração. Além disso, a construção de uma barragem, chamado pelo mesmo nome, foi construído para armazenar água devido ao aumento das atividades agrícolas, foram observados, no entanto vazamentos preocupantes foram observados para os quais foram realizados Tomografia Eléctrica nessas áreas potenciais, foram distribuído quatro perfis, uma paralela ao eixo da barragem de 10 a 15 metros a montante a partir do primeiro perfil, no lado exterior e o quarto perfil aproximadamente 10 metros acima da fonte de água. Assim, as medições de resistividade foram feitas para cada uma das 4 linhas de Tomografia Eléctrica, a fim de obter informações pormenorizadas sobre a estratigrafia na área de estudo e identificar anomalias georesistivas causadas por tectônismo ou falhas geológicas, que refletem como áreas de resistividades tão baixas ou anomalias. Analisada a área de estudo foram encontrados fratura locais consideráveis, que foram recomendadas a ser impermeabilizadas rapidamente, porque o risco de infiltrações é latente.  Palavras-chave: infiltração, fratura, investigação geofísica, método elétrico.    

scholarly journals Effect of Industrial Effluents on Rice Growth, Yield and Soil Chemical Properties

2020 ◽  
pp. 1-17
Author(s):  
Md Rafiqul Islam ◽  
Golam Kibria Muhammad Mustafizur Rahman ◽  
Abu Saleque
Keyword(s):  
Waste Water ◽  
Heavy Metals ◽  
Chemical Properties ◽  
Growth Yield ◽  
Industrial Effluents ◽  
Dry Season ◽  
Soil Chemical Properties ◽  
Cropping Pattern ◽  
Wet Season ◽  
Tannery Effluents

Toxic pollutants and heavy metals in industrial effluents and city waste water are massive concern among the researchers, development worker, media personnel and policy makers. Keeping this in view-a pot experiment was conducted at the Bangladesh Rice Research Institute (BRRI), net house during T. Aman 2010 (wet season) and Boro 2011 (dry season) rice aimed to determining the effect of different industrial effluents on rice growth, yield and soil chemical properties. The irrigation effect of industrial effluents on rice production was more prominent in dry season (Boro) rice than wet season (T. Aman) rice. Perceptible changes in soil properties occurred through the effluents irrigation in rice-rice cropping pattern. Pharmaceutical and tannery effluents increased soil pH, EC, total N (%) available P (mg/kg). Exchangeable K, Ca, Mg and Na (cmol/kg) were increased due to irrigation with dyeing, pharmaceutical and tannery effluents. Dyeing, beverage, tannery and city waste water reduced percent soil organic carbon. Micronutrients (Zn, Fe, Cu and Mn) were increased significantly by the irrigation with dyeing, pharmaceutical and tannery effluents in both wet and dry season rice.  Heavy metals like Pb, Cd, Ni and Cr in soils were increased significantly through irrigation with effluents in rice-rice cropping pattern.

scholarly journals Assessment of Environmental Pollution of Heavy Metals Deposited on the Leaves of Trees in Yazd Bus Terminals

2021 ◽  
Author(s):  
motahareh esfandiari ◽  
Mohammad Ali Hakimzadeh
Keyword(s):  
Heavy Metals ◽  
Spatial Distribution ◽  
Green Space ◽  
Pearson Correlation ◽  
Correlation Coefficients ◽  
Principal Component ◽  
Absorption Spectrometry ◽  
Urban Transport ◽  
Heavy Elements ◽  
And Cluster Analysis

Abstract There is a lack of information about urban transport activity in adding heavy elements to the environment. This research assesses concentration some of heavy elements in the deposited atmospheric dust in Yazd bus terminals. Dust samples were collected from the green space in the bus terminals of urban transportation. Following the digestion by nitric acid, determination of the total metal concentration of cadmium(Cd), cobalt(Co), copper(Cu), nickel(Ni), lead(Pb), zinc(Zn), chromium (Cr), and manganese(Mn) in the dust were performed via Atomic Absorption Spectrometry. The map representing the spatial distribution of metals was plotted and their source was identified using Pearson correlation coefficients, Principal Component Analysis(PCA), and Cluster Analysis(CA). The findings indicated that the mean concentration of heavy metals in the deposited dust on the leaves of the trees was in the following order; Cd < Co < Ni < Pb < Cu < Zn < Cr < Mn. The map representing the spatial distribution of heavy metal concentrations indicated that the abundance of metals in different stations varies according to their location. Two important sources for the concentration of heavy metals in the deposited dust on the leaves were identified. The sources of Co, Cd, Mn, and Ni were anthropogenic and lithogenic, and the sources of Pb, Zn, Cr and Cu were the traffic and industrial activities. The amounts of EF, CF, IPI and, RI Indicators in residential, commercial, green space and environmental uses were estimated at low to extremely high levels of pollution. The findings showed that the growth of industrialization and human activities had caused contamination of the environment by heavy metals emitted into the atmosphere of Yazd.

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