Retardation of arsenic transport through a Pleistocene aquifer
| Autor: | Peter J. Oates, Jacob L. Mey, Benjamin C. Bostick, Pham Thi Kim Trang, K. A. Radloff, Michael Berg, Nguyen-Ngoc Mai, Alexander van Geen, Caroline Stengel, Mason Stahl, Vi Mai Lan, Beth Weinman, Pham Hung Viet, Phu Dao Manh, Z. Aziz, Rolf Kipfer, Charles F. Harvey, Felix Frei |
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| Rok vydání: | 2013 |
| Předmět: |
Geologic Sediments
010504 meteorology & atmospheric sciences Groundwater flow Water Wells Population Geochemistry chemistry.chemical_element Food Contamination Aquifer 010501 environmental sciences 01 natural sciences Article Arsenic Rivers Groundwater pollution Arsenic Poisoning Water Movements Humans education Groundwater 0105 earth and related environmental sciences geography education.field_of_study Multidisciplinary geography.geographical_feature_category Drinking Water Silicon Dioxide Carbon 6. Clean water Arsenic contamination of groundwater Vietnam chemistry Environmental science Oxidation-Reduction Water well |
| Zdroj: | Nature |
| ISSN: | 1476-4687 0028-0836 |
| DOI: | 10.1038/nature12444 |
| Popis: | Groundwater drawn daily from shallow alluvial sands by millions of wells over large areas of south and southeast Asia exposes an estimated population of over a hundred million people to toxic levels of arsenic. Holocene aquifers are the source of widespread arsenic poisoning across the region. In contrast, Pleistocene sands deposited in this region more than 12,000 years ago mostly do not host groundwater with high levels of arsenic. Pleistocene aquifers are increasingly used as a safe source of drinking water and it is therefore important to understand under what conditions low levels of arsenic can be maintained. Here we reconstruct the initial phase of contamination of a Pleistocene aquifer near Hanoi, Vietnam. We demonstrate that changes in groundwater flow conditions and the redox state of the aquifer sands induced by groundwater pumping caused the lateral intrusion of arsenic contamination more than 120 metres from a Holocene aquifer into a previously uncontaminated Pleistocene aquifer. We also find that arsenic adsorbs onto the aquifer sands and that there is a 16-20-fold retardation in the extent of the contamination relative to the reconstructed lateral movement of groundwater over the same period. Our findings suggest that arsenic contamination of Pleistocene aquifers in south and southeast Asia as a consequence of increasing levels of groundwater pumping may have been delayed by the retardation of arsenic transport. |
| Databáze: | OpenAIRE |
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