Naturally occurring arsenic in drinking water poses a growing global health risk as large numbers of people unknowingly consume unsafe levels, researchers said on Wednesday.
The problem is bigger than scientists had thought, and it affects nearly 140 million people in more than 70 countries, according to new research presented at the annual Royal Geographical Society meeting in London.
Arsenic can cause lung disease and cancers, even long after people stop drinking contaminated water, said Peter Ravenscroft, a researcher at the University of Cambridge.
“What is new is, the extent of arsenic pollution is much bigger than people realized,” Mr. Ravenscroft said in a telephone interview.
“There is a very important connection between arsenic in water and arsenic in food, especially where people grow irrigated crops.”
World Health Organization guidelines set a safe limit of 10 parts per billion of arsenic in water supplies, but tens of millions of people in the world drink unsafe water above that level, researchers said.
At present, Bangladesh has been affected the most. There, hundreds of thousands of people are likely to die from arsenic poisoning, the researchers said.
Arsenic has also been found in the water in developed countries, and industrial activities like mining can also lead to contamination.