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In this study, the hydrogeochemical program PHREEQC was used to determine the chemical speciation and mineral saturation indices (SIs) of groundwater in the vicinity of the proposed high-level nuclear waste repository at Yucca Mountain, Nevada (USA). In turn, these data were used to interpret the origin and recharge mode of groundwater, to elucidate the mechanisms of flow and transport, and to determine potential sources of groundwater contamination. PHREEQC was run to determine aqueous dissolved species and minerals that would be in equilibrium with the study area’s groundwater. Selected major ions, associated SI, F− and Ca/Na ion exchange were then examined using the multivariate statistical methods of principal component factor analysis and k-means cluster analysis. Analysis of dissolved ion concentrations, SIs, and Ca/Na ion exchange allows simultaneous consideration of arithmetic (raw concentrations) and logarithmic (SI, ion exchange) variables that describe the hydrochemical system and, therefore, can provide further insight into the system’s behavior. The analysis indicates that the dominant processes and reactions responsible for the hydrochemical evolution in the system are (1) evaporative concentration prior to infiltration, (2) carbonate equilibrium, (3) silicate weathering reactions, (4) limited mixing with saline water, (5) dissolution/precipitation of calcite, dolomite and fluorite, and (6) ion exchange. Principal component factor analysis and k-means cluster analysis of factor scores allow the reduction of dimensions describing the system and the identification of hydrogeochemical facies and the processes that defined and govern their evolution.Statistical analysis results indicate that the northern, west face and southern Yucca Mountain groundwater is fresh water with low concentrations of Ca2+, Mg2+, Cl−, Ca2+/(Na+)2, and CaF2. The Fortymile Wash groundwater is dilute. The carbonate signature is shown in the Ash Meadows and Death Valley waters with high fluorite SI. Finally, the Crater Flat, Stripped Hills, and Skeleton Hills are dominated by Ca/Na ion exchange, Mg and Ca. The hydrochemical and statistical analyses showed three main groundwater signatures or hydrochemical processes indicating groundwater evolution, potential flowpaths, and recharge areas. The flowpaths are the trace of the Amargosa River, the trace of Fortymile Wash, and its convergence with the Amargosa River. This appears to represent not just a groundwater flow path, but traces of surface runoff infiltration as well. 相似文献
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Stormwater along ephemeral arroyos and areal infiltration in nearby boreholes were studied in the Amargosa Desert Region of Southern Nevada, USA. Chemical composition of ephemeral stream runoff was measured at elevations below where areal infiltration generally occurs in arid environments using lysimeters designed for this study. Borehole cuttings from several wells were evaluated in terms of chloride migration. Analysis of the borehole data indicates that net areal infiltration has been insignificant for the past 10 000+ years. This is associated with an environment where chloride and other soluble salts accumulate in shallow sediments and potentially in runoff waters. Measured storm events during the 4‐year study period were small and localized but sufficient to produce surface runoff, at least near the lysimeters. Composition of storm runoff captured by the lysimeters was found to be a combination of the water chemistry types found in precipitation and from leaching tests of near‐surface sediments. All major cations and bicarbonate increased relative to chloride when precipitation interacted with sediments to form ephemeral stream runoff. The changes were consistent with calculated saturation indices. Despite the long‐term accumulation of chloride in soils and deep sediments caused by complete evapotranspiration of infiltrating precipitation, runoff waters were characterized by low chloride and total dissolved solids. This study presents a limitation of the chloride mass‐balance method, as chloride and water migration were disassociated from each other in the study area. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
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Multivariate statistical methods (MSMs) applied to ground water chemistry provide valuable insight into the main hydrochemical species, hydrochemical processes, and water flowpaths important to ground water evolution. The MSMs of principal component factor analysis (FA) and k-means cluster analysis (CA) were sequentially applied to major ion chemistry from 211 different ground water-sampling locations in the Amargosa Desert. The FA reduces the number of variables describing the system and finds relationships between major ions. The CA of the reduced system produced objective hydrochemical facies, which are independent of, but in good agreement with, lithological data. The derived factors and hydrochemical facies are innovatively presented on biplots, revealing composition of hydrochemical processes and facies, and overlaid on a digital elevation model, displaying flowpaths and interactions with geologic and topographic features in the region. In particular, a distinct ground water chemical signature is observed beneath and surrounding the extended flowpath of Fortymile Wash, presenting some contradiction to contemporary water levels along with potential interaction with a fault line. The signature surrounding the ephemeral Fortymile Wash is believed to represent the relic of water that infiltrated during past pluvial periods when the amount of runoff in the wash was significantly larger than during the current drier period. This hypothesis and aforementioned analyses are supported by the examination of available chloride, oxygen-18, hydrogen-2, and carbon-14 data from the region. 相似文献
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A new conceptual model for release rate of radionuclides from the proposed repository for high level nuclear waste located at Yucca Mountain, Nevada is developed. The model predicts that heat generated from radioactive decay combined with the unsaturated environment will lead to an inward flow system that, under many relevant conditions, will slow the release of and sometimes sequester radionuclides at locations of higher heat release and lower water percolation. The amount of protection will be greatest for more concentrated waste forms such as spent fuel and less for glass waste forms. The redistribution and concentration of the radionuclides is anticipated to significantly delay radionuclide release and create a tendency towards gradual release over time that is independent of localized penetrations of metallic barriers. 相似文献
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Masood Ahsan Siddiqui Syed Mohammad Rashid Lubna Siddiqui Shahzad Ali Ansari 《Journal of the Indian Society of Remote Sensing》2012,40(1):109-119
The paper tries to estimate the rate of waste generation per head/per day, to identify suitable sites for waste disposal,
to find out optimal route for collection vehicles and to analyze the financial aspects of solid waste management in Moradabad
City, India.The study is based on sample of 2,500 households and secondary data. The City generates about 318 tones of solid
waste with an average per capita rate of 460 gram per day. Collection and disposal efficiency is nearly 64%. Sensitivity analysis
of the present disposal site as per the norms of Central Pollution Control Board indicates that it is moderately suitable.
Subsequently two new disposal sites were identified. Redefined routes and related issues were evaluated in financial terms.
It is estimated that by adopting the proposed plan, the expenditure on waste management will increase by about 52%, but at
the same time about 90% of city area and 95% of city population will be served. 相似文献
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Integration of geoelectric and hydrochemical approaches for delineation of groundwater potential zones in alluvial aquifer 
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下载免费PDF全文 Qaisar Mehmood Muhammad Arshad Muhammad Rizwan Shanawar Hamid Waqas Mehmood Muhammad Ansir Muneer Muhammad Irfan Lubna Anjum 《地下水科学与工程》2020,8(4):366-380
Geoelectric and hydrochemical approaches are employed to delineate the ground-water potential zones in District Okara, a part of Bari Doab, Punjab, Pakistan. Sixty-seven VES surveys are conducted with the Electrical Resistivity Meter. The resultant resistivity verses depth model for each site is estimated using computer-based software IX1D. Aquifer thickness maps and interpreted resistivity maps were generated from interpreted VES results. Dar-Zarrouk parameters, transverse resistance (TR), longitudinal conductance (SL) and anisotropy (λ) were also calculated from resistivity data to delineate the potential zones of aquifer. 70% of SL value is ≤3S, 30% of SL value is > 3S. According to SL and TR values, the whole area is divided into three potential zones, high, medium and low potential zones. The spatial distribution maps show that north, south and central parts of study area are marked as good potential aquifer zones. Longitudinal conductance values are further utilized to determine aquifer protective capacity of area. The whole area is characterized by moderate to good and up to some extent very good aquifer protective area on the basis of SL values. The groundwater samples from sixty-seven installed tube wells are collected for hydro-chemical analysis. The electrical conductivity values are determined. Correlation is then developed between the EC (μS/cm) of groundwater samples vs. interpreted aquifer resistivity showing R2 value 0.90. 相似文献
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