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Millions of Chinese at risk of arsenic poisoning

Arsenic from rocks can get into drinking water if wells are sunk in the wrong place. A survey has highlighted areas of China in danger of contamination

TWENTY million Chinese people are in danger of arsenic poisoning from drinking water, according to a new risk-mapping technique.

Arsenic occurs naturally in the world’s rock, dissolving in underground water that can pollute wells. If consumed over decades, it can cause cancers, as well as other kidney and liver diseases. The hazard is recognised, but few countries undertake the laborious task of testing each well.

Luis Rodriguez-Lado of the in Dübendorf, and Chinese colleagues, developed a system using geological warning signs that revealed the two most susceptible landscape – alkaline inland drainage basins and delta regions with new river sediments. Globally, the latter includes Bangladesh, the scene of what the World Health Organization called .

The team tested their model in China, and identified two previously unsuspected areas likely to be at risk: parts of the north China basin and Sichuan province (Science, ).

The system should help ensure any plans to tap dangerous groundwater are scrapped.