Spatial variability of arsenic in 6000 tube wells in a 25 km<sup>2</sup> area of Bangladesh

Geen, Alexander van; Zheng, Yan; Versteeg, Roelof; Stute, M.; Horneman, A.; Dhar, Ratan; Steckler, Michael S.; Gelman, Andrew; Small, Christopher; Ahsan, Habibul; Graziano, Joseph H.; Hussain, Ijaz; Ahmed, Kazi Matin

doi:10.1029/2002wr001617

Cited by 337 publications

(261 citation statements)

References 22 publications

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“…In the Mekong Delta, dramatic changes occurred in vegetation types, flooding patterns, hydraulic gradients, and mineral weathering (27,28). Evidence of these changes is seen in the abundance of ferric (hydr)oxides that give Pleistocene sands in Bangladesh their oft-noted brown or orange color (8,10,13,29,30). These oxidized deposits have a higher capacity for arsenic adsorption (4,21,31) and are associated with aquifers that are low in dissolved arsenic, which are found at greater depths in the Bengal Basin owing to higher sedimentation rates.…”

Section: Resultsmentioning

confidence: 99%

Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence

Erban¹,

Gorelick²,

Zebker

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

218

120

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Deep aquifers in South and Southeast Asia are increasingly exploited as presumed sources of pathogen- and arsenic-free water, although little is known of the processes that may compromise their long-term viability. We analyze a large area (>1,000 km 2 ) of the Mekong Delta, Vietnam, in which arsenic is found pervasively in deep, Pliocene–Miocene-age aquifers, where nearly 900 wells at depths of 200–500 m are contaminated. There, intensive groundwater extraction is causing land subsidence of up to 3 cm/y as measured using satellite-based radar images from 2007 to 2010 and consistent with transient 3D aquifer simulations showing similar subsidence rates and total subsidence of up to 27 cm since 1988. We propose a previously unrecognized mechanism in which deep groundwater extraction is causing interbedded clays to compact and expel water containing dissolved arsenic or arsenic-mobilizing solutes (e.g., dissolved organic carbon and competing ions) to deep aquifers over decades. The implication for the broader Mekong Delta region, and potentially others like it across Asia, is that deep, untreated groundwater will not necessarily remain a safe source of drinking water.

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Section: Resultsmentioning

confidence: 99%

Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence

Erban¹,

Gorelick²,

Zebker

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

218

120

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“…The locations of the well nests were chosen to cover the spatial patterns of groundwater As concentrations established by a previous survey of 6000 wells distributed over a ~ 25 km 2 area of Araihazar in central Bangladesh (van Geen et al, 2003). A total of 37 monitoring wells from 5-91 m in depth were installed at 6 sites ( Fig.1a, Table 1).…”

Section: Monitoring Wellsmentioning

confidence: 99%

“…The spatial variability of groundwater As concentrations at scales of 10 1 to 10 4 m has been well documented for Holocene (<10 kyr old) fluvial-deltaic aquifers of the Bengal Basin (BGS & DPHE, 2001;van Geen et al, 2003;Yu et al, 2003). There is growing evidence that at least part of this heterogeneity can be attributed to variations in local geology and its effect on shallow groundwater flow Stute et al, 2007;Aziz et al, in revision;Weinman et al, in press.).…”

Section: Introductionmentioning

confidence: 99%

Temporal variability of groundwater chemistry in shallow and deep aquifers of Araihazar, Bangladesh

Dhar

Zheng

Stute

et al. 2008

Journal of Contaminant Hydrology

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109

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Samples were collected every 2-4 weeks from a set of 37 monitoring wells over a period of 2-3 years in Araihazar, Bangladesh, to evaluate the temporal variability of groundwater composition for As and other constituents. The monitoring wells are grouped in 6 nests and span the 5-91 m depth range. Concentrations of As, Ca, Fe, K, Mg, Mn, Na, P, and S were measured by high-resolution ICPMS with a precision of 5% or better; concentrations of Cl were measured by ion chromatography. In shallow wells <30 m deep, As and P concentrations generally varied by <30%, whereas concentrations of the major ions (Na, K, Mg, Ca and Cl) and the redox-sensitive elements (Fe, Mn, and S) varied over time by up to ± 90%. In wells tapping the deeper aquifers > 30 m often below clay layers concentrations of groundwater As were much lower and varied by <10%. The concentrations of major cations also varied by <10% in these deep aquifers. In contrast, the concentration of redox-sensitive constituents Fe, S, and Mn in deep aquifers varied by up to 97% over time. Thus, strong decoupling between variations in As and Fe concentrations is evident in groundwaters from shallow and deep aquifers.Comparison of the time series data with groundwater ages determined by 3 H/ 3 He and 14 C dating shows that large seasonal or inter-annual variations in major cation and chloride concentrations are restricted to shallow aquifers and groundwater recharged < 5 years ago. There is no corresponding change in As concentrations despite having significant variations of redox sensitive constituents in these very young waters. This is attributed to chemical buffering due to rapid equilibrium between solute and solid As. At two sites where the As content of groundwater in existing shallow wells averages 102 µg/L (range: < 5 to 648 µg/L; n=118) and 272 µg/L (range: 10 to 485 µg/L; n=65), respectively, a systematic long-term decline in As concentrations lends support to the notion that flushing may slowly deplete an aquifer of As. Shallow aquifer water with > 5 yr 3 H/ 3 He age show a constant As:P molar ratio of 9.6 over time, suggesting common mechanism of mobilization.Corresponding author, Y. Zheng,

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“…According to van Geen et al (2003), an estimated 88% of contaminated wells are located within 100 meters of an uncontaminated well, giving rise to substantial within-village variation in contamination.…”

Section: Empirical Frameworkmentioning

confidence: 99%

Poisoning the mind: Arsenic contamination of drinking water wells and children's educational achievement in rural Bangladesh

Asadullah

Chaudhury

2011

Economics of Education Review

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Standard-Nutzungsbedingungen:Die Dokumente auf EconStor dürfen zu eigenen wissenschaftlichen Zwecken und zum Privatgebrauch gespeichert und kopiert werden.Sie dürfen die Dokumente nicht für öffentliche oder kommerzielle Zwecke vervielfältigen, öffentlich ausstellen, öffentlich zugänglich machen, vertreiben oder anderweitig nutzen.Sofern die Verfasser die Dokumente unter Open-Content-Lizenzen (insbesondere CC-Lizenzen) zur Verfügung gestellt haben sollten, gelten abweichend von diesen Nutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte. Terms of use: Documents in EconStor may be saved and copied for your personal and scholarly purposes.You are not to copy documents for public or commercial purposes, to exhibit the documents publicly, to make them publicly available on the internet, or to distribute or otherwise use the documents in public. licence. www.econstor.eu Any opinions expressed here are those of the author(s) and not those of IZA. Research published in this series may include views on policy, but the institute itself takes no institutional policy positions. If the documents have been made available under an Open Content Licence (especially Creative Commons Licences), you may exercise further usage rights as specified in the indicated D I S C U S S I O N P A P E R S E R I E SThe Institute for the Study of Labor (IZA) in Bonn is a local and virtual international research center and a place of communication between science, politics and business. IZA is an independent nonprofit organization supported by Deutsche Post Foundation. The center is associated with the University of Bonn and offers a stimulating research environment through its international network, workshops and conferences, data service, project support, research visits and doctoral program. IZA engages in (i) original and internationally competitive research in all fields of labor economics, (ii) development of policy concepts, and (iii) dissemination of research results and concepts to the interested public.IZA Discussion Papers often represent preliminary work and are circulated to encourage discussion. Citation of such a paper should account for its provisional character. A revised version may be available directly from the author. Bangladesh has experienced the largest mass poisoning of a population in history owing to contamination of groundwater with naturally occurring inorganic arsenic. Prolonged drinking of such water risks development of diseases and therefore has implications for children's cognitive and psychological development. This study examines the effect of arsenic contamination of tubewells, the primary source of drinking water at home, on the learning outcome of school-going children in rural Bangladesh using recent nationally representative data on secondary school children. We unambiguously find a negative and statistically significant correlation between mathematics scores and arsenic-contaminated drinking tubewells at home, net of the child's socio-economic status, parental background and sc...

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Spatial variability of arsenic in 6000 tube wells in a 25 km² area of Bangladesh

Cited by 337 publications

References 22 publications

Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence

Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence

Temporal variability of groundwater chemistry in shallow and deep aquifers of Araihazar, Bangladesh

Poisoning the mind: Arsenic contamination of drinking water wells and children's educational achievement in rural Bangladesh

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Spatial variability of arsenic in 6000 tube wells in a 25 km2 area of Bangladesh

Cited by 337 publications

References 22 publications

Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence

Release of arsenic to deep groundwater in the Mekong Delta, Vietnam, linked to pumping-induced land subsidence

Temporal variability of groundwater chemistry in shallow and deep aquifers of Araihazar, Bangladesh

Poisoning the mind: Arsenic contamination of drinking water wells and children's educational achievement in rural Bangladesh

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Spatial variability of arsenic in 6000 tube wells in a 25 km² area of Bangladesh