NANNING - Cadmium pollutants have been found in the lower reaches of a contaminated river in South China's Guangxi Zhuang autonomous region, local authorities said Thursday.

Excessive cadmium levels were detected in the Longjiang River, a subsidiary of Liujiang River in Hechi city on January 15, killing fish and prompting panic buying of bottled water.

The pollution has reached the Liujiang River in Liuzhou city as of Thursday, said Gan Jinglin, head of the Liuzhou environmental protection bureau.

The cadmium density of water samples in the first several kilometers of the main stream downstream Longjiang River was 0.006 milligrams per liter of water on late Thursday afternoon, 20 percent higher than the official limit, Gan said.

But the water in a lower section which supplies drinking water for the city was still safe, he added.

Despite the assurance from the authorities, many residents in Liuzhou have rushed to buy bottled water in panic.

"The bottled water will be used for drinking and cooking. We only use tap water for baths and cleaning," said a resident surnamed Liu, who bought three boxes of bottled water at a supermarket.

The local authorities also have ordered to discharge more water from upstream hydropower projects to dilute the pollution and also stepped up testing of water samples to give timely updates.

Guangxi Jinhe Mining Co Ltd has been held responsible for discharging waste and therefore polluting the river water.

Cadmium, a chemical that is mostly found in industrial effluents, is carcinogen.

Over the last week, local fire authorities in Hechi city had put hundreds of tonnes neutralizers, made from dissolved aluminum chloride, into the Longjiang River to dissolve the contamination.