Arsenic pollution of groundwater in Vietnam exacerbated by deep aquifer exploitation for more than a century.
Arsenic contamination of shallow groundwater is among the biggest health threats in the developing world. Targeting uncontaminated deep aquifers is a popular mitigation option although its long-term impact remains unknown. Here we present the alarming results of a large-scale groundwater survey covering the entire Red River Delta and a unique probability model based on three-dimensional Quaternary geology. Our unprecedented dataset reveals that ∼7 million delta inhabitants use groundwater contaminated with toxic elements, including manganese, selenium, and barium. Depth-resolved probabilities and arsenic concentrations indicate drawdown of arsenic-enriched waters from Holocene aquifers to naturally uncontaminated Pleistocene aquifers as a result of > 100 years of groundwater abstraction. Vertical arsenic migration induced by large-scale pumping from deep aquifers has been discussed to occur elsewhere, but has never been shown to occur at the scale seen here. The present situation in the Red River Delta is a warning for other As-affected regions where groundwater is extensively pumped from uncontaminated aquifers underlying high arsenic aquifers or zones.
Eawag, Swiss Federal Institute of Aquatic Science and Technology, Ueberlandstrasse 133, 8600 Dübendorf, Switzerland.
Lenny H E
LH
Winkel
Thi Kim Trang
TK
Pham
Mai Lan
ML
Vi
Caroline
C
Stengel
Manouchehr
M
Amini
Thi Ha
TH
Nguyen
Hung Viet
HV
Pham
Michael
M
Berg
D000465:Algorithms; D001151:Arsenic / Q000032:analysis*; D001464:Barium / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D005843:Geography; D006801:Humans; D016015:Logistic Models; D008345:Manganese / Q000032:analysis; D018570:Risk Assessment; D045483:Rivers / Q000737:chemistry*; D012643:Selenium / Q000032:analysis; D014744:Vietnam; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
D014874:Water Pollutants, Chemical; D001464:Barium; D008345:Manganese; D012643:Selenium; D001151:Arsenic
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