Factors controlling As and U in shallow ground water, southern Carson Desert, Nevada

Welch, Alan H.; Lico, Michael S.

doi:10.1016/s0883-2927(97)00083-8

Cited by 212 publications

(88 citation statements)

References 39 publications

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“…Arsenic, the redox sensitive element, is commonly more soluble in oxidized groundwater occurring as oxyanion AsO 4 2-or H 2 AsO 4 -. However, in reducing waters, arsenic tends to be incorporated in insoluble minerals (Langmuir 1997;Welch and Lico 1998). PC 2 with 15 % of the total variance in both the seasons loads positive scores of Cd, Co, Cr, Pb and Zn in the wet season and Cd, Co, Cu, Fe and Mn in the dry season.…”

Section: Principal Component Analysismentioning

confidence: 99%

Multivariate statistical evaluation of heavy metals in the surface water sources of Jia Bharali river basin, North Brahmaputra plain, India

Khound¹,

Bhattacharyya

2016

Appl Water Sci

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The aim of this study was to assess the quality of surfacewater sources in the Jia Bharali river basin and adjoining areas of the Himalayan foothills with respect to heavy elements viz. (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) by hydrochemical and multivariate statistical techniques, such as cluster analysis (CA) and principal component analysis (PCA). This study presents the first ever systematic analysis on toxic elements of water samples collected from 35 different surface water sources in both the dry and wet seasons for a duration of 2 hydrological years (2009)(2010)(2011). Varimax factors extracted by principal component analysis indicates anthropogenic (domestic and agricultural run-off) and geogenic influences on the trace elements. Hierarchical cluster analysis grouped 35 surfacewater sources into three statistically significant clusters based on the similarity of water quality characteristics. This study illustrates the usefulness of multivariate statistical techniques for analysis and interpretation of complex data sets, and in water quality assessment, identification of pollution sources/factors and understanding temporal/spatial variations in water quality for effective surfacewater quality management.

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Section: Principal Component Analysismentioning

confidence: 99%

Multivariate statistical evaluation of heavy metals in the surface water sources of Jia Bharali river basin, North Brahmaputra plain, India

Khound¹,

Bhattacharyya

2016

Appl Water Sci

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“…Evaporation can increase the concentrations of analytes including trace elements in the residual waters (e.g. Fujii and Swain, 1995;Welch and Lico, 1998;Smedley and Kinniburgh, 2002). The presence of soluble evaporite minerals may also enhance solute concentrations, although the distribution of evaporites within this sector of DB is noted to be limited.…”

Section: Groundwater From Boreholesmentioning

confidence: 99%

Geological factors controlling occurrence and distribution of arsenic in groundwaters from the southern margin of the Duero Basin, Spain

Giménez-Forcada

Smedley

2014

Environ Geochem Health

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Groundwater from springs and boreholes on the southern edge of the Cenozoic Duero Basin (DB) of Spain has concentrations of arsenic (As) which are commonly above the EC drinking-water limit of 10 µg/L, and reach observed values up to 241 µg/L. Groundwater compositions within the sedimentary aquifer vary from Ca-HCO 3 type, variably affected by evaporation and agricultural pollution at shallow levels, to Na-HCO 3 compositions in deeper boreholes of the basin. Groundwater conditions are mainly oxidising but reducing groundwaters exist in sub-basins within the aquifer, localised flow paths likely being influenced by basement structure. Arsenic concentrations are spatially variable, reaching up to 38 µg/L in springs of the Spanish Central System (SCS) basement aquifer and up to 62 µg/L in springs from the DB. Highest As concentrations are associated with the Na-HCO 3 compositions in deep boreholes (200-450 m depth) within the DB. These have high pH values (up to 9.6) can give rise to associated elevated concentrations of V and U (up to 64 µg/L and 30 µg/L respectively). In the deep borehole waters of the DB, oxidising flows derived from the mineralised igneous-metamorphic basement and discharging via major faults, are considered the origin of the higher concentrations. Compositions are consistent with desorption of As and other anionic species from metal oxyhydroxides in an oxic environment. Under locally reducing conditions prevalent in some low-flow parts of the DB, an absence of detectable dissolved As is coincident with low or undetectable SO 4 concentrations, and consistent with loss via formation of authigenic sulphide minerals. Mitigation measures are needed urgently in this semi-arid region where provision of alternative sources of safe drinking water is logistically difficult and expensive.

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“…The present data also show that a poor correlation exists between Fe 2+ and As, a ®nding that con®rms similar observations by Sa®ullah (1998). Presumably, Fe 2+ does not behave conservatively in these waters, probably because it precipitates as FeCO 3 Welch and Lico, 1998 …”

mentioning

confidence: 98%

“…This mechanism is considered by Bhattacharaya et al (1997) to be a more likely As source than is pyrite oxidation and the process has been documented to occur in groundwater elsewhere (e.g. Matiso et al, 1982;Welch and Lico, 1998). The process dissolves Fe oxyhydroxide and releases to groundwater both Fe 2+ and the sorbed load of the Fe oxyhydroxide, which includes As.…”

mentioning

confidence: 99%

Mechanism of arsenic release to groundwater, Bangladesh and West Bengal

Nickson

McArthur

Ravenscroft³

et al. 2000

Applied Geochemistry

1,163

626

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In some areas of Bangladesh and West Bengal, concentrations of As in groundwater exceed guide concentrations, set internationally and nationally at 10 to 50 mg l À1 and may reach levels in the mg l À1 range. The As derives from reductive dissolution of Fe oxyhydroxide and release of its sorbed As. The Fe oxyhydroxide exists in the aquifer as dispersed phases, such as coatings on sedimentary grains. Recalculated to pure FeOOH, As concentrations in this phase reach 517 ppm. Reduction of the Fe is driven by microbial metabolism of sedimentary organic matter, which is present in concentrations as high as 6% C. Arsenic released by oxidation of pyrite, as water levels are drawn down and air enters the aquifer, contributes negligibly to the problem of As pollution. Identi®cation of the mechanism of As release to groundwater helps to provide a framework to guide the placement of new water wells so that they will have acceptable concentrations of As. #

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Factors controlling As and U in shallow ground water, southern Carson Desert, Nevada

Cited by 212 publications

References 39 publications

Multivariate statistical evaluation of heavy metals in the surface water sources of Jia Bharali river basin, North Brahmaputra plain, India

Multivariate statistical evaluation of heavy metals in the surface water sources of Jia Bharali river basin, North Brahmaputra plain, India

Geological factors controlling occurrence and distribution of arsenic in groundwaters from the southern margin of the Duero Basin, Spain

Mechanism of arsenic release to groundwater, Bangladesh and West Bengal

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