Dataset Information

Redox trapping of arsenic during groundwater discharge in sediments from the Meghna riverbank in Bangladesh.

ABSTRACT: Groundwater arsenic (As) is elevated in the shallow Holocene aquifers of Bangladesh. In the dry season, the shallow groundwater discharges to major rivers. This process may influence the chemistry of the river and the hyporheic zone sediment. To assess the fate of As during discharge, surface (0-5 cm) and subsurface (1-3 m) sediment samples were collected at 9 sites from the bank of the Meghna River along a transect from its northern source (25 degrees N) to the Bay of Bengal (22.5 degrees N). Bulk As concentrations of surface sediment averaged 16 +/- 7 mg/kg (n = 9). Subsurface sediment contained higher mean concentrations of As of 4,000 mg/kg (n = 14), ranging from 1 to 23,000 mg/kg As, with >100 mg/kg As measured at 8 sites. X-ray absorption near-edge structure spectroscopy indicated that As was mainly arsenate and arsenite, not As-bearing sulfides. We hypothesize that the elevated sediment As concentrations form as As-rich groundwater discharges to the river, and enters a more oxidizing environment. A significant portion of dissolved As sorbs to iron-bearing minerals, which form a natural reactive barrier. Recycling of this sediment-bound As to the Ganges-Brahmaputra-Meghna Delta aquifer provides a potential source of As to further contaminate groundwater. Furthermore, chemical fluxes from groundwater discharge from the Ganges-Brahmaputra-Meghna Delta may be less than previous estimates because this barrier can immobilize many elements.

SUBMITTER: Datta S

PROVIDER: S-EPMC2761342 | biostudies-literature | 2009 Oct

REPOSITORIES: biostudies-literature

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Redox trapping of arsenic during groundwater discharge in sediments from the Meghna riverbank in Bangladesh.

Datta S S Mailloux B B Jung H-B HB Hoque M A MA Stute M M Ahmed K M KM Zheng Y Y

Proceedings of the National Academy of Sciences of the United States of America 20090921 40

Groundwater arsenic (As) is elevated in the shallow Holocene aquifers of Bangladesh. In the dry season, the shallow groundwater discharges to major rivers. This process may influence the chemistry of the river and the hyporheic zone sediment. To assess the fate of As during discharge, surface (0-5 cm) and subsurface (1-3 m) sediment samples were collected at 9 sites from the bank of the Meghna River along a transect from its northern source (25 degrees N) to the Bay of Bengal (22.5 degrees N). B ...[more]

PMID: 19805180

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Project description:BackgroundIn Bangladesh, riverbank erosion is a major problem that regularly displaces millions of people and affects their mental health every year.ObjectivesThe primary objective is to explore the effects of riverbank erosion on mental health problems such as depression, anxiety, and stress in Bangladesh.MethodsWe conducted a household survey from August 2019 to November 2019 on randomly selected adult respondents from Rajbari District located along the Ganges River and Tangail District located along the Brahmaputra River. The respondents were divided into two groups: exposed and non-exposed to riverbank erosion. All participants were asked to complete self-reported questionnaires on the Depression, Anxiety and Stress Scale-21, and other socio-demographic, economic and riverbanks erosion-related factors. We performed Chi-squared test and multiple logistic regression analysis to explore the significant risk factors (P<0.05) of mental illness (depression, anxiety and stress).ResultsWe surveyed 611 households, of whom 410 were from Rajbari and 201 were from Tangail. Among 611 respondents, 509 (83.31%) were exposed by riverbank erosion whereas 102 (16.69%) were non-exposed. The prevalence of depression, anxiety and stress (DAS) was 38.30%, 76.60%, 32.41%, respectively, and they were significantly higher among the exposed group than the non-exposed group (depression: 45.19% versus 3.92%, P<0.001; anxiety: 82.71% versus 46.08%, P<0.001; stress: 38.11% versus 3.92%, P<0.001). The respondents exposed to river erosion were respectively 8.28, 2.26 and 5.09 times more likely to develop DAS disorder compared to their non-exposed counterparts (ORD = 8.28, 95% CI = 2.75-24.89; ORA = 2.26, 95% CI = 1.31-3.88; ORS = 5.09, 95% CI = 1.64-15.76). Females and those who lost their houses and displaced, were more likely to have DAS disorder compared to their respective counterparts.ConclusionsThe exposed people were more likely to experience mental health problem and demand some social safety net programs with special focus on female and those who lost houses and displaced.

Dataset Information

Redox trapping of arsenic during groundwater discharge in sediments from the Meghna riverbank in Bangladesh.

Publications

Redox trapping of arsenic during groundwater discharge in sediments from the Meghna riverbank in Bangladesh.

Similar Datasets

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