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 Swiss Federal Institute of Aquatic Science and Technology 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 largest poisoning of a population in history”.

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, doi.org/nkx).


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

This article appeared in print under the headline “Deadly well water”