@article{749f5ff694f146cf8dd7e87fa2bce8b8,
title = "High-Arsenic Groundwater in the Southwestern Bengal Basin Caused by a Lithologically Controlled Deep Flow System",
abstract = "Elevated arsenic in Bengal Basin aquifers threatens human health. Most deep (>150 m) groundwater in Pleistocene aquifers is low in arsenic; however higher concentrations have been reported in the southwest border region. Here, we establish that this extensive arsenic contamination at depth is not associated with well failure. A combination of geochemistry and flow modeling constrains the factors that contribute to arsenic contamination at depth in this region. Deep groundwater in the affected area is younger (2.0 ± 0.6 kyr) than deep, low-arsenic groundwater elsewhere (12.0 ± 4.0 kyr) based on radiocarbon. Stratigraphic data indicate pre-Holocene deposition of the contaminated aquifers, but few low-permeability strata. Numerical modeling indicates that this stratigraphic anomaly permits a natural flow system that transports shallow groundwater to depth. Thus, in areas lacking low-permeability layers, arsenic contamination can occur in pre-Holocene aquifers and is probably not an early sign of future deep contamination in regions with interbedded low-permeability strata.",
keywords = "Bengal Basin, arsenic, groundwater, groundwater dating, groundwater modeling, water resources",
author = "Khan, {M. R.} and Michael, {H. A.} and B. Nath and Huhmann, {B. L.} and Harvey, {C. F.} and A. Mukherjee and I. Choudhury and M. Chakraborty and Ullah, {M. S.} and Ahmed, {K. M.} and Goodbred, {S. L.} and P. Schlosser and Bostick, {B. C.} and Mailloux, {B. J.} and T. Ellis and {van Geen}, A.",
note = "Funding Information: ). This is LDEO publication number 8363. The authors thank Md. Delwaruzzaman of Dhaka University, Md. Jubair of Jessore Technical College and Shouvik Mahanty of University of Calcutta for field assistance, the Jessore DPHE office, West Bengal PHED, and Dr. Anwar Zahid for well depths and locations, and Richard Winston of USGS for technical help in groundwater flow modelling. This work was funded by the U.S. National Science Foundation (ICER1414131) and a Delaware Environmental Institute Fellowship to M. R. K. Data can be accessed from CUAHSI Hydroshare (Khan, Funding Information: The authors thank Md. Delwaruzzaman of Dhaka University, Md. Jubair of Jessore Technical College and Shouvik Mahanty of University of Calcutta for field assistance, the Jessore DPHE office, West Bengal PHED, and Dr. Anwar Zahid for well depths and locations, and Richard Winston of USGS for technical help in groundwater flow modelling. This work was funded by the U.S. National Science Foundation (ICER1414131) and a Delaware Environmental Institute Fellowship to M. R. K. Data can be accessed from CUAHSI Hydroshare (Khan,). This is LDEO publication number 8363. Publisher Copyright: {\textcopyright}2019. American Geophysical Union. All Rights Reserved.",
year = "2019",
month = nov,
day = "28",
doi = "10.1029/2019GL084767",
language = "English (US)",
volume = "46",
pages = "13062--13071",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "22",
}