19.6 million people in China are at risk of being exposed to unsafe levels of arsenic in contaminated groundwater, according to new research published in the journal ‘Science’ this month.

Researchers from Switzerland and China collaborated on a groundbreaking study that used geological maps and geological data to pinpoint areas more likely to be affected by the poison.

The results of the study revealed the extent of this health threat in China, including areas that had not been previously thought to be affected. This is particularly worrying for northern China which is so heavily dependent on groundwater.

Although these results must then be confirmed with field measurements, this new method is a huge step forward as until now, calculating the scale of arsenic contamination in a country was very difficult. Especially for large countries such as China which has over 10 million drinking wells that needs to be screened.

It is hoped that the findings will help Chinese authorities to manage their well screening programmes, by allowing them to prioritise screening wells in possible arsenic hotspots. Contaminated wells can then be treated or taken out of use.