HECHI, Guangxi - More efforts are being put into mitigating cadmium pollution in a river in Guangxi Zhuang autonomous region that threatens the water safety of downstream cities, local authorities said Monday.

Environmental protection workers have been dumping neutralizers, made from dissolved aluminum chloride, at five locations on the Longjiang River to dissolve the contamination.

Cleanup work will be conducted at two more locations, six km downstream of Luodong hydropower station, where the pollutants were concentrated Sunday night, and another further downstream, somewhere near Sancha hydropower station, said Qin Bin, deputy secretary of the Hechi city committee of the Communist Party of China.

"It is a critical time right now as the downstream drinking water safety is in jeopardy, so we will take every measure possible and optimize our strategies to bring down cadmium concentration levels," Hechi mayor He Xinxing added.

The contamination was first detected on January 15 and was traced to a plant belonging to Guangxi Jinhe Mining Co Ltd.

In Hechi, the pollution killed many fish and prompted panic buying of bottled water over the past week.

Cadmium is a carcinogenic chemical mostly found in industrial effluents.

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