LIUZHOU, Guangxi - The cadmium pollution in a river in South China's Guangxi Zhuang autonomous region following a spill from an industrial plant has been controlled and no new leakage has been found, local environmental authorities said on Sunday.

The cadmium concentration in the Lalang section of the Longjiang River in the city of Yizhou, where the spill occurred, has been brought within the restricted level, said Gan Jinglin, head of the environmental protection bureau of the downstream city of Liujiang.

Armed police dump bags of alkali into water to dissolve the contamination at the Nuomitan waterpower plant in Liucheng county of Liuzhou city, Guangxi Zhuang autonomous region, Jan 27, 2012. [Photo/Xinhua]

Industrial waste from a local mining company spilt it into the Longjiang River, a tributary upstream of the Liujiang River which runs through Liujiang city, being detected on Jan 15.

The cadmium pollutants have now reached the Luodong hydropower station on the Longjiang River, and still pose a threat to water safety in Liujiang, according to experts with the task force handling the incident.

"As the pollutants spread over a large section of Longjiang and are moving downstream, Liujiang is still under threat, but we are able to ensure safe drinking water to residents," Gan said.

"Even when pollutants flow into the Liujiang River, it takes 70 more hours to reach the source of the drinking water supply in Liujiang city, which means we have had time to take emergency response measures."

Cadmium is a carcinogenic chemical mostly used in industrial effluents.

An agent designed to promote the clumping-together of pollutants has been dumped into a dam on the Longjiang River to help dredging the matter.

The production of all seven heavy metal producers along the upstream section of the Longjiang River has been suspended in a bid to curb potential sources of new pollution.

Guangxi Jinhe Mining Co Ltd has been held responsible for the contamination.