About 140 million people, mainly in developing countries, are being poisoned by arsenic in their drinking water, researchers believe. Speaking at the Royal Geographical Society (RGS) annual meeting in London, scientists said this would lead to higher rates of cancer in the future, a private TV channel reported.
South and East Asia account for more than half of the known cases globally. Eating large amounts of rice grown in affected areas could also be a health risk, scientists said.
"It's a global problem, present in 70 countries, probably more," said Peter Ravenscroft, a research associate in geography with Cambridge University. "If you work on drinking water standards used in Europe and North America, then you see that about 140 million people around the world are above those levels and at risk."
Arsenic consumption leads to higher rates of some cancers, including tumours of the lung, bladder and skin, and other lung conditions. Some of these effects show up decades after the first exposure. "In the long term, one in every 10 people with high concentrations of arsenic in their water will die from it," observed Allan Smith from the University of California at Berkeley.
"This is the highest known increase in mortality from any environmental exposure." The international response, he said, is not what the scale of the problem merits.
"I don't know of one government agency which has given this the priority it deserves," he commented. The first signs that arsenic-contaminated water might be a major health issue emerged in the 1980s, with the documentation of poisoned communities in Bangladesh and the Indian state of West Bengal.
In order to avoid drinking surface water, which can be contaminated with bacteria causing diarrhoea and other diseases, aid agencies had been promoting the digging of wells, not suspecting that well water would emerge with elevated levels of arsenic. The metal is present naturally in soil, and reaches into groundwater, with bacteria thought to play a role.
Since then, large-scale contamination has been found in other Asian countries such as China, Cambodia and Vietnam, in South America and Africa.
It is less of a problem in North America and Europe where most water is provided by utilities. However, some private wells in the UK may not be tested and could present a problem, Ravenscroft said.
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