Cadmium pollution in a river in the Guangxi Zhuang Autonomous Region has been controlled and no new leaks have been found following a spill from an industrial plant, local environmental authorities said Sunday. 

Cadmium concentrations in the Longjiang River in Yizhou, where the spill occurred, have been brought to within acceptable levels, said Gan Jinglin, head of the environmental protection bureau of Liujiang.

The cadmium pollutants are mainly concentrated near the Luodong hydropower station on the Longjiang River and still pose a threat to water safety in Liujiang.

"Since the pollutants were spread over a large section of the Longjiang River and are moving downstream, Liujiang is still threatened, but we have been able to secure safe drinking water for local residents," Gan said.

The cadmium concentration at the Nuomitan hydropower station, 56 kilometers away from the Hexi water plant in Liuzhou, was seven times higher than the official limit of 0.005 milligrams per liter as of 10 am Sunday, Gan said.

Water located within a 16-kilometer radius from the Hexi water plant is considered vital for water supply safety. The Sunday morning tests showed that the cadmium concentration on a section of the river located 16 kilometers from the plant was 0.0041 milligrams per liter, just below the official limit, Gan said.

"However, the rising cadmium concentration means that the pollutants are approaching, and it is still unknown when the concentration peak will occur and how high it will be," Gan said.

A chemical agent designed to clump the contaminants together has been dumped into a dam on the Longjiang River to assist in cleanup efforts.

All seven of the heavy metal production plants located upstream of the river have suspended operations to curb potential sources of new pollution.

Xinhua