HONG KONG - MORE than a quarter of drinking wells in Vietnam's densely-populated Red River delta contain unsafe levels of arsenic that can cause cancer, neurological problems and hypertension, researchers warned on Tuesday.
In a paper published in the journal Proceedings of the National Academy of Sciences, they also said 44 per cent of the wells in the delta carried levels of manganese that exceed World Health Organization guidelines.
'About 7 million people are at a considerable risk of chronic arsenic poisoning. This is particularly worrying because groundwater is the main source of drinking water throughout the delta,' lead author Michael Berg wrote in an email to Reuters.
Experts have long known that groundwater in parts of southeast Asia contain unsafe levels of arsenic, a naturally occurring chemical, but their locations have never been clear.
'Sixty-five percent of the groundwater wells in the Red River delta contain naturally occurring toxic elements, at levels which exceed the World Health Organization's (WHO) safety standards,' Mr Berg wrote.
According to the WHO, water containing more than 10 micrograms of arsenic per litre is unsafe, and chronic poisoning leads to accumulations in the skin, hair, and nails, resulting in skin pigmentation, hypertension and neurological dysfunctions. It may also cause cancer in the skin, lungs, bladder and kidney. -- REUTERS
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