(CNN) -- It could be the worst mass poisoning in history. And the terrible irony is that it may all be due to an idealistic push to clean up drinking water for some of the world's poorest people.
A new study published in British medical journal The Lancet says that up to 77 million people in Bangladesh are being exposed to toxic levels of arsenic, potentially taking years or decades off their lives.
An international team of researchers from Chicago, New York and Bangladesh followed 12,000 people over the past decade, monitoring their arsenic intake and mortality rates from contaminated wells.
By the end of the study, one in five deaths were determined to be directly related to elevated arsenic levels in their system. Stretch that over the entire population that takes its water from wells, and the impact is daunting.
The problem has been known about for years, if not the overall deadly impact.
