Workshop proposal: Recovering Uncompromised Samples of Aquifer Sands with In-Situ Groundwater from up to 300-m Depth in South and Southeast Asia

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Groundwater aquifers are the main source of drinking water for about 2 billion people worldwide. There is, however, growing public health concern about chronic exposure to natural, geogenic contaminants that can be released from uncontaminated sediment to groundwater. Natural constituents of untreated groundwater currently recognized to be of significant health concern include fluoride, manganese, and particularly arsenic in South and Southeast Asia. The groundwater and sediment properties that regulate the release of these potentially toxic constituents are often highly variable both vertically and laterally. This high degree of spatial variability combined with a lack of technology for sampling groundwater and aquifer sands simultaneously without exposure to drilling fluid or atmospheric oxygen are a key reason that contributing biogeochemical and hydrological factors have been difficult to isolate. A promising avenue for overcoming this limitation is the addition of an in situ freezing package to form a plug at the bottom of a core collected with existing wire-line drilling tools developed by DOSECC (Drilling, Observation and Sampling of the Earth?s Continental Crust Inc.), a not-for-profit corporation supported in part by the National Science Foundation. This proposal is a request to supplement an existing workshop grant from the International Continental Scientific Drilling Program to develop the necessary sampling technology and to generate a science plan for deploying the new technology over the next ten years. By analogy to large experiments in physics, the availability of unique technology could foster the level of collaboration within a community of geoscientists that is better suited than disparate efforts of the past to understanding a complex environmental issue such as the groundwater arsenic problem in South and Southeast Asia. Mitigation in the affected region continues to be hampered by uncertainty concerning the sustainability of pumping from deep low-arsenic aquifers that are increasingly tapped to provide safe drinking water to millions of villagers. The proposed technology will contribute to reducing this uncertainty and could subsequently be deployed for research on other issues related to groundwater quality.