REPORT / INTERNATIONAL NEWS

Since rivers and ponds in Bangladesh were contaminated with bacteria, Bangladeshis switched to wells. But soon after, in the early ‘80s, researchers realized those wells were harming Bangladeshis with a new poison—arsenic.

Using a six-square-mile test plot, the researchers found that the organic carbon comes from shallow ponds that were dug to provide soil for flood protection. The carbon compounds sink in the pondwater and seep underground where bacteria digest them, setting up the perfect chemical conditions to free up the soil’s arsenic. Groundwater flow then brings the arsenic-rich water to the wells.

Future wells dug deep enough, to the low-arsenic part of the aquifer, could help. Rice fields filter arsenic from the water, so wells under
those fields could also be part of an answer to a problem affecting millions of Bangladeshis.