© ICDP, the International Continental Scientific Drilling Program, 1996-2022

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International Drilling to Recover Aquifer Sands (IDRAs) and Arsenic Contaminated Groundwater in Asia

Asia, Bangladesh, Cambodia, India, Nepal, Vietnam

new full-proposal: ICDP-2012/01
for the funding-period starting 2012-01-15
by Alexander (Lex) van Geen, Arthur (Art) J. Spivack, Kazi Matin Uddin Ahmed, Roger Beckie, Laurent Charlet, Thomas Neumann, Alagappan (AL) Ramanathan, Harue Masuda, Bishal Nath Upreti, Prosun Bhattacharya, Michael Berg, Jonathan Richard Lloyd
Abstract
Elevated groundwater arsenic (As) concentrations impact the health of over 100 million villagers across Pakistan, Nepal, India, Bangladesh, Myanmar, Cambodia, Vietnam, and China who rely on tubewells as their main source of drinking water. Groundwater from these areas can contain 10 to 100-times the World Health Organization’s guideline of 10 ug/L for As in drinking water. Chronic exposure to such elevated As levels is known to cause deadly cancers, cardiovascular disease, and inhibit the mental development of children. There is broad agreement within the international scientific community that a key factor underlying this major public health crisis is the release of As to groundwater upon reductive dissolution of iron (Fe) oxyhydroxides, a process that is mediated by micro-organisms involved in the mineralization of reactive organic carbon. What remains unsettled despite more than a decade of research is whether groundwater or sediment is the main source of the reactive organic carbon. It is also unclear to what extent adsorption of As onto aquifer sands could delay the contamination of adjacent or underlying aquifers that are low in As. Without being able to address these two key issues, it is not possible to make meaningful predictions about the time scale over which low-As aquifers could be contaminated by the incursion of high-As water drawn by massive groundwater pumping in certain parts of the affected region. This is a crucial question from a public health perspective because selectively tapping low-As aquifers has proved to be more effective for lowering As exposure than most other forms of mitigation, including groundwater treatment or rainwater harvesting. The guiding hypothesis for this project is that the distribution of As in reducing groundwater is anchored to the local geology across a range of spatial scales and therefore naturally evolves on 100–1000 year time scales. Human perturbations of the natural groundwater flow could threaten aquifers in Asia that are currently low in As on 10-yr time scales, however. This full proposal to ICDP, likely to be the first of several devoted to groundwater quality over the next decade, seeks to identify the limited set of parameters that need to be considered in order to make meaningful predictions about the vulnerability of a low-As aquifer in the absence of a full-scale study.
Scientific Objectives
  • This proposal is submitted by scientists based in 16 different countries seeking to drill an unconsolidated aquifer in the US that is elevated in As in 2013. Most of the critical measurements will be carried out in the field in central Illinois soon after core recovery by 16 scientists and students from South, Southeast, and East Asia. Besides shedding light on generalizable processes that regulate As levels in groundwater, the project will be an occasion to optimize a series of field procedures and set the stage for future international drilling in Asia. At up to 5 locations, sediment will be cored and archived continuously to a depth of 300 ft (90 m). The freeze-shoe sampler, a new tool under development, will subsequently be deployed in 5 parallel holes to recover groundwater in contact with aquifer sands from the same depth by sealing the bottom of a coring tube by in situ freezing. Up to five 3-m cores will be collected with the freeze-shoe sampler from each hole and processed on-site in a mobile geomicrobiology laboratory where a suite of labile sediment and groundwater properties will be measured. Additional funding for more advanced analysis of archived material by multiple laboratories will be sought by individual investigators through various research organizations.
Keywords
Aquifer, Arsenic, Asia, Drilling, Groundwater, ICDP-2012/01, IDRAS, Pollusion, Public health, Sampling
Location
Asia, Bangladesh, Cambodia, India, Nepal, Vietnam: 21.03333, 105.85000

© ICDP, the International Continental Scientific Drilling Program, 1996-2022

www.icdp-online.org