It's a sad reality I wrote about in The Last Taboo: To avoid getting sick from waterborne diseases—chronic diarrhea, hookworm, dysentery, typhoid, cholera—in their monsoon ponds, the people of West Bengal, India, and of Bangladesh have been turning to tube wells. But a different death awaits from well water—cancers of the skin, bladder, and lung, among others. Thankfully, there are solutions.
According to a new study in the medical journal The Lancet, between 33 and 77 million people in Bangladesh have been exposed to arsenic in the drinking water. The World Health Organization calls it the largest mass poisoning in history.
- One in five deaths in Bangladesh (population: 125 million) is associated with exposure to water from wells with arsenic concentrations greater than 10 micrograms per liter.
- Arsenic exposure is with increased mortality due to heart disease and other chronic diseases in addition to the more familiar medical consequences of arsenic exposure: skin lesions, cancers of the skin, bladder and lung.
- An increase of nearly 70 percent in all-cause mortality was found among those exposed to the highest concentration of arsenic in water (150 to 864 micrograms/liter).
- Researchers also found a dose-related effect that included increased mortaility even at relatively low levels of exposure, including the Bangladesh safety standard (50 micrograms/liter) and the WHO recommended standard (10 micrograms/liter).
The poisoning is the result of well-intentioned efforts on the part of aid and development agencies in the 1970s when 10 million tube wells were built to combat waterborne diseases. While the new wells reduced exposure to some diseases, they also yielded water contamined with arsenic, which occurs naturally in the region.
The arsenic can be avoided by digging deeper wells—an approach already yielding safer drinking water for roughly 100,000 people in Bangladesh—and by deploying filtering systems.
I wrote about the benefits of a a deeper tube for well Supta Halder, her extended family, even her cows, in The Last Taboo.