"The largest mass poisoning in history," according to the World Health Organization, is in Bangladesh, where there's arsenic in the groundwater used by more than half of the population.
Arsenic is a colorless and odorless element that can occur naturally in soil. Excessive and long-term exposure can cause various cancers and skin abnormalities. Bangladesh has the highest levels of naturally occurring arsenic in groundwater in the world, reports Al Jazeera. But this wasn't discovered until the mid-90s, after humanitarian agencies dug a lot of wells to prevent locals from drinking water from dirty ponds.
More than 70 percent of the population in Bangladesh live in rural areas and get drinking water from wells.
With more than 30 years of exposure, Bangladeshis are now facing health problems that include skin lesions, lung cancer, heart disease and kidney failure. But these conditions are often undetected because arsenic poisoning isn't always physically visible. Only 30 percent of Bangladeshis have access to basic health care, so the actual measure of the impact arsenic poisoning is likely under-reported. Even without an accurate measure, the WHO considers the scale of the health epidemic even larger than the 1986 nuclear meltdown at Chernobyl, which led to more than 100,000 people being diagnosed with fatal cancers.
The Bangladeshi government and development agencies are investing in water filter systems and trying to spread the word about the dangers of drinking from the groundwater wells. But getting rural communities to stop using their primary source for cool, clean-looking water is easier said than done, reports Al Jazeera. Installing household water filtration systems is not affordable for most villagers. Boiling water is still an option, but it's extremely difficult to change daily practices of people who already have limited resources and are unable to see and understand the effects on their health.
The following trailer from the documentary Arsenic: The Largest Mass Poisoning in History shows the devastating effects of Bangladesh's poisoned groundwater.