Induced polarization,resistivity, and self-potential: a case history of contamination evaluation due to landfill leakage   总被引：2，自引：1，他引：1  

José Domingos Faraco Gallas  Fabio Taioli  Walter Malagutti Filho 《Environmental Earth Sciences》2011,63(2):251-261

This article compares the efficiency of induced polarization (IP) and resistivity in characterizing a contamination plume due to landfill leakage in a typical tropical environment. The resistivity survey revealed denser electrical current flow that induced lower resistivity values due to the high ionic content. The increased ionic concentration diminished the distance of the ionic charges close to the membrane, causing a decrease in the IP phenomena. In addition, the self-potential (SP) method was used to characterize the preferential flow direction of the area. The SP method proved to be effective at determining the flow direction; it is also fast and economical. In this study, the resistivity results were better correlated with the presence of contamination (lower resistivity) than the IP (lower chargeability) data.  相似文献   

Ecological consideration of trace element contamination in sediment cores from Sundarban wetland,India   总被引：2，自引：1，他引：1  

E. V. Silva Filho  M. P. Jonathan  M. Chatterjee  S. K. Sarkar  S. M. Sella  A. Bhattacharya  K. K. Satpathy 《Environmental Earth Sciences》2011,63(6):1213-1225

This article reports on the concentration of selected trace elements (Mn, Zn, Cr, Cu, Ba, As, B, V, and Hg) and major elements (Fe and Al) from the intertidal sediment cores from Sundarban wetland, India. This is a typical meso-macrotidal estuarine area affected by domestic and industrial activities located upstream. The overall concentrations range is low to moderate, indicating the environmental conditions in the outfall zone (grain size, hydrodynamic regime, and confinement), which favors the in situ accumulation of pollutants. The extent of contamination from trace elements in Sundarban core sediments is evaluated through a two-pronged approach: (i) by determining the metal enrichment in the sediments through the calculation of Pollution Load Index (PLI), Enrichment Factor (EF) and Index of Geoaccumulation (I _geo), and (ii) by defining a potential level of biological risk by the use of quality criteria such as Threshold Effect Level (TEL) and Effects Range-Low (ERL) benchmarks. On the basis of the calculated indices, sediments are particularly enriched with Cr, Cu, B, V, and As. Those enrichments seem to be due to the fine granulometry of the regions with Fe and Mn oxi-hydroxides being the main metal carriers. Trace Elements input to the Sundarban wetland need to be kept under strict control in future specially with reference to As since, according to TEL and ERL benchmarks, it already appears to be associated with a potential biological risk.  相似文献   

Aspects of the geology, petrology and chemistry of some Angolan carbonatites   总被引：1，自引：0，他引：1  

A. Issa Filho  A.B.R.M.D. Dos Santos  B.F. Riffel  F.E.V. Lapido-Loureiro  I. McReath   《Journal of Geochemical Exploration》1991,40(1-3)

Using published data and the results of a new study, the main characteristics of seven Angolan carbonatite complexes are here presented. With the exception of the Lupongola complex which intrudes anorthosites, the remaining complexes are hosted by Precambrian silicic rocks. The complexes are of central or dike type and are well exposed. They represent some of the seven morpholithological types present in the province and have some intermediate lithochemical features between those of Brazilian and East African examples.Sovites at Lupongola are the richest in Sr and F, and also have the highest CaO/MgO and La/Y ratios of all sovites studied. Carbonatites from Bonga and Bailundo are the richest in P₂O₅, while those from Coola and Longonjo are the richest in BaO. Ferrocarbonatites from Bailundo and Virulundo have the highest REE contents. TiO₂ contents are usually low. Only Bonga carbonatites show well-defined variation between Ba and Mn contents and the index CaO/(CaO+Fe₂O₃+FeO+MnO+MgO).The CO₂-SiO₂-(Al₂O₃+Na₂O+K₂O) diagram distinguishes silicified carbonatites, feldspar-bearing carbonatites in which the main silicate mineral is K-feldspar, carbonatites and fenites. Potassic fenitization of country rocks is well developed at Bailundo, Bonga and Virulundo, and probably it also affected cogenetic nepheline syenites at Tchivira and Monte Verde.Fluorcarbonates of Ca and REE are encountered in all chemical varieties of carbonatites, and crystallized during late stages of rock formation. They have a strong influence both on total REE contents and on the slopes of chondrite-normalized patterns. Fluorapatite and pyrochlore are other important potential REE host minerals in the rocks studied. The REE patterns usually have discrete negative Ce anomalies, and sometimes show very discrete negative Eu anomalies. Apart from these anomalies, some rocks have very near-linear patterns, but most show inflections, which may occur between light and middle, and between middle and heavy REE. The origins of these variations are still uncertain.Other aspects of rock geochemistry show that, while some features could be explained by crystal fractionation differentiation processes, late-stage or secondary chemical modifications were widespread.  相似文献   

Anthropic Exposure Indicator for River Basins Based on Landscape Characterization and Fuzzy Inference     

Elfany Reis do Nascimento Lopes  Carlos de Souza  José  Paixão de Sousa  Jocy Ana  Filho  José Luiz Albuquerque  Lourenço  Roberto Wagner 《Water Resources》2021,48(1):29-40

Water Resources - The objective of this study is to develop an anthropic exposure indicator for river basins using quantitative and qualitative aspects of the landscape and morphometric analysis...  相似文献   

Numerical solution for consolidation and desiccation of soft soils     

Daniel T. C. Yao  Waldyr Lopes de Oliveira‐Filho  Xiao‐Chuan Cai  Dobroslav Znidarcic 《国际地质力学数值与分析法杂志》2002,26(2):139-161

The consolidation and desiccation behaviour of soft soils can be described by two time‐dependent non‐linear partial differential equations using the finite strain theory. Analytical solutions do not exist for these governing equations. In this paper, we develop efficient numerical methods and software for finding the numerical solutions. We introduce a semi‐implicit time integration scheme, and show numerically that our method converges. In addition, the numerical solution matches well with the experimental result. A boundary refinement method is also developed to improve the convergence and stability for the case of Neumann type boundary conditions. Interface governing equations are derived to maintain the continuity of consolidation and desiccation processes. This is useful because the soil column can undergo desiccation on top and consolidation on the bottom simultaneously. The numerical algorithms has been implemented into a computer program and the results have been verified with centrifuge test results conducted in our laboratory. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

Hydrochemical assessment of surface water in watersheds near the Uranium Mining and Milling Facilities of Caldas,Brazil     

C. A. de Carvalho Filho  R. M. Moreira  B. F. Guimarães  V. V. M. Ferreira  L. M. L. A. Auler  H. E. L. Palmieri  A. F. Oliveira  P. H. Dutra 《Environmental Earth Sciences》2016,75(3):187

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Introduction to the special issue on adaptive flood risk management     

O&#;Hare  Paul  Cavan  Gina  Filho  Walter Leal 《Natural Hazards》2016,82(2):145-148

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Platinum-group minerals in the Limoeiro Ni–Cu–(PGE) sulfide deposit,Brazil: the effect of magmatic and upper amphibolite to granulite metamorphic processes on PGM formation     

J. Mota-e-Silva  H. M. Prichard  C. F. Ferreira Filho  P. C. Fisher  I. McDonald 《Mineralium Deposita》2015,50(8):1007-1029

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Hydrological modelling and water balance of the Negro River basin: evaluation based on in situ and spatial altimetry data     

A. C. V. Getirana  M.‐P. Bonnet  O. C. Rotunno Filho  W. Collischonn  J.‐L. Guyot  F. Seyler  W. J. Mansur 《水文研究》2010,24(22):3219-3236

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Hydrogeochemical and Flow Modeling of Aquitard Percolation in the Cariri Valley-Northeast Brazil     

Carlos José Freire Machado  Maria Marlúcia Freitas Santiago  Luiz Alberto Ribeiro Mendonça  Horst Frischkorn  Josué Mendes Filho 《Aquatic Geochemistry》2007,13(2):187-196

Flow modeling and hydrogeochemical inversion calculations were performed on the aquifer systems of the Crato-Juazeiro Graben in the Araripe Sedimentary Basin of the Cariri Valley, Northeast Brazil, in order to assess aquifer interconnections through an aquitard of the Araripe Plateau. Steady state hydraulic head numeric calculations with the finite difference method used Modflow software with hydrologically based boundary conditions and a piezometric surface as initial condition. Hydrogeochemical inversion with PHREEQC was performed for two water samples representing typical initial and final waters along the flow path. Flow simulation shows that approximately 20% of all recharge water from the superior aquifer system passes through the Santana aquitard reaching the middle aquifer system. Quantification of mineral dissolution/precipitation processes, ion exchange and microbiological redox reactions taking place in the aquifer systems also indicates hydraulic interconnection of the superior and middle aquifer systems through the Santana aquitard.  相似文献