Arsenic fate in the Brahmaputra river basin aquifers: Controls of geogenic processes, provenance and water-rock interactions

Verma, Swati; Mukherjee, Abhijit; Mahanta, Chitralekha; Choudhury, Runti; Badoni, Rakesh P.; Joshi, Gopal

doi:10.1016/j.apgeochem.2019.06.004

Cited by 37 publications

(8 citation statements)

References 74 publications

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“…The shaded region within the solid lines indicates 1σ variation of the means. The total adsorbent mass concentrations of ferrihydrite (F), goethite (G), and manganese dioxide (M) were assumed to be 454, 378, and 1.3 g L –1 , respectively, based on the reported literature. − IGP stands for the Indo-Gangetic Plain.…”

Section: Resultsmentioning

confidence: 99%

“…A three-plane CD-MUSIC model for ferrihydrite and goethite and a diffuse layer model for manganese dioxide , were used to quantify the surface charge and its electrostatics. The average bulk density (2.07 g cm –3 ), porosity (0.44), and concentrations of Fe (64.2 mg g –1 ) and Mn (221.1 μg g –1 ) from reported total elemental concentrations in Indian aquifer sediments − were used to make estimates of the average concentrations (±1σ) of ferrihydrite as 123 ± 69 g kg –1 , goethite as 102 ± 57 g kg –1 , and of manganese dioxide as 350 ± 401 mg kg –1 . The estimated phase concentrations were conservative upper limits, given that measurements in sediments sampled from the Bengal delta have suggested only ∼27% of total Fe as ferrihydrite and ∼21% of total Fe as goethite .…”

Section: Theory and Calculationsmentioning

confidence: 99%

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Investigation of Potential Drivers of Elevated Uranium Prevalence in Indian Groundwaters with a Unified Speciation Model

Sujathan

Singh

2023

Environ. Sci. Technol.

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Elevated uranium (U) (>WHO limit of 30 μg L −1 ) in Indian groundwaters is primarily considered geogenic, but the specific mineralogical sources and mechanisms for U mobilization are poorly understood. In this contribution, statistical and geochemical analyses of well-constrained metadata of Indian groundwater quality (n = 342 of 8543) were performed to identify key parameters and processes that influence U concentrations. For geochemical predictions, a unified speciation model was developed from a carefully compiled and updated thermodynamic database of inorganic, organic (Stockholm Humic model), and surface complexation reactions and associated constants. Critical U contamination was found at shallow depths (<100 m) within the Indo-Gangetic plain, as determined by bivariate nonparametric Kendall's Tau b and probability-based association tests. Analysis of aquifer redox states, multivariate hierarchical clusters, and principal components indicated that U contamination was predominant not just in oxic but mixed (oxic−anoxic) aquifers under high Fe, Mn, and SO 4 concentrations, presumably due to U release from dissolution of Fe/Mn oxides or Fe sulfides and silicate weathering. Most groundwaters were undersaturated with respect to relevant U-bearing solids despite being supersaturated with respect to atmospheric CO 2 (average pCO 2 of reported dissolved inorganic carbonate (DIC) data = 10 −1.57 atm). Yet, dissolved U did not appear to be mass limited, as predicted solubilities from reported sediment concentrations of U were ∼3 orders of magnitude higher. Integration of surface complexation models of U on typical aquifer adsorbents, ferrihydrite, goethite, and manganese dioxide, was necessary to explain dissolved U concentrations. Uranium contamination probabilities with increasing dissolved Ca and Mn exhibited minima at equilibrium solubilities of calcite [∼50 mg L −1 ] and rhodochrosite [∼0.14 mg L −1 ], respectively, at an average groundwater pH of ∼7.5. A potential indirect control of such U-free carbonate solids on U mobilization was suggested. For locations (n = 37) where dissolved organic carbon was also reported, organic complexes of U contributed negligibly to dominant U speciation at the groundwater pH. Overall, the unified model suggested competitive dissolution−precipitation and adsorption−desorption controls on U speciation. The model provides a quantitative framework that can be extended to understand dominant mobilization mechanisms of geogenic U in aquifers worldwide after suitable modifications to the relevant aquifer parameters.

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Section: Resultsmentioning

confidence: 99%

Section: Theory and Calculationsmentioning

confidence: 99%

Investigation of Potential Drivers of Elevated Uranium Prevalence in Indian Groundwaters with a Unified Speciation Model

Sujathan

Singh

2023

Environ. Sci. Technol.

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“…These peridotites and serpentine rocks also form the geology of aquifers connected with surface waters of the Koniambo Massif (Dewandel et al, 2017;Genthon et al, 2017;Jeanpert et al, 2019). These two elements have a higher solubility under alkaline pH and reducing conditions prevailing in underground reservoirs (Peters, 2008;Ryan, Peter et al, 2011;Kinniburgh, 2002, 2001;Verma et al, 2019). The lack of median values higher than the geochemical background of the dissolved values probably indicates a more significant contribution of groundwater in dissolved As and Zn than sedimentary leaching.…”

Section: Markers Of Mining Activitiesmentioning

confidence: 99%

Potential contamination of stream waters by ultramafic mining sediments: Identification of geochemical makers (New Caledonia)

Boula

Laporte-Magoni

Gunkel-Grillon

et al. 2022

Journal of Geochemical Exploration

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“…The eastern syntaxis region contains only 4% of the total Brahmaputra area catchment but contributes more than 45% of sediment load [23][24][25]. It consists of highly metamorphized rock formation involving deformed meta-sedimentary, meta-igneous and calc-alkaline plutons surrounded by marbles, phyllites and quartzites [26,27]. Sampling sites of the Brahmaputra River in Arrunachal Pradesh (S1-S5) and Assam (S6-S10), India (map drawn from Google Earth Pro and using QGIS 3.12 mapping software).…”

Section: Study Area: Site Description and Geologymentioning

confidence: 99%

Metal Fractionation in Surface Sediments of the Brahmaputra River and Implications for Their Mobilization

Tsering

Sillanpää

Рейникайнен

et al. 2020

IJERPH

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The Brahmaputra River is the largest tropical river in India that flows along the Himalayan regions and it is the lifeline of millions of people. Metal fractionation in the Brahmaputra River’s surface sediments and its correlation with turbidity are assessed in this study. The interaction between metal fractions and the overlying water is studied using multivariate statistical analyses. The strong positive correlation between NH4 of the overlying water and the exchangeable fractions in sediments signifies that the metals in the exchangeable fractions can be substituted by NH4. Subsequently, these metals can be released into the overlying water. The fluctuation in turbidity from 73 to 875 NTU indicates a large variation in the suspended matter concentration, and a higher concentration of suspended matter could provide attachment sites for pollutants such as metals. Significant variation in turbidity manifests a potentially high risk of pollution. In addition, the observation of local people along the Brahmaputra River turning its color to muddy indicates the need for continuous monitoring of water quality and an assessment of pollution is crucial. Although the Brahmaputra River’s risk assessment code is at low risk, the exchangeable fractions of Ni and Zn are present at all sites. Thus, the Brahmaputra River requires early preventive measures and management strategies to control metal pollution. This study contributes to an understanding of the fluctuation of turbidity of a tropical river. We provide baseline data for policymakers, and the importance of further intensive studies on metal pollution in the Himalayan Rivers is highlighted.

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Arsenic fate in the Brahmaputra river basin aquifers: Controls of geogenic processes, provenance and water-rock interactions

Cited by 37 publications

References 74 publications

Investigation of Potential Drivers of Elevated Uranium Prevalence in Indian Groundwaters with a Unified Speciation Model

Investigation of Potential Drivers of Elevated Uranium Prevalence in Indian Groundwaters with a Unified Speciation Model

Potential contamination of stream waters by ultramafic mining sediments: Identification of geochemical makers (New Caledonia)

Metal Fractionation in Surface Sediments of the Brahmaputra River and Implications for Their Mobilization

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