Groundwater is a precious resource worldwide, especially in communities where surface water is scarce or contaminated. Clay layers are widely thought to protect these valuable groundwater aquifers from above-ground pollutants and contaminants.
But, new research recently published in Nature Communications has shown that in Bangladesh, clay layers that were thought to protect underlying aquifers from downward migration of naturally-occurring, high-arsenic water from shallow aquifers, are actually making arsenic groundwater contamination worse.
“This study documents the long-term rise in arsenic concentrations in an aquifer lying below a clay layer,” said study co-author Dr. Peter Knappett, associate professor in the Department of Geology and Geophysics at Texas A&M University. “Above that clay layer is a shallow aquifer with high arsenic concentrations. This deeper of the two aquifers is a crucial source of safe drinking water for much of the rural population of Bangladesh.”
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