In late March, residents of southern Hunan were passing on an emergency notice from environmental authorities about thallium pollution in the Leishui River.
The river feeds into several local water supply plants, and villages draw from it for use at home and on farms.
An emergency response had been triggered four hours after abnormal levels of the metal were identified, the notice stated.
Thallium, a toxic element which causes both acute and chronic poisoning, is an uncommon pollutant and China’s standards for surface water quality do not require testing for it.
Quick action meant the quality of water at supply plants was not affected, and there have been no reports of harm to health.
“In the past, thallium contamination had been discovered after the fact,” Ma Jun of the Institute of Public and Environmental…
