BEIJING — China is dumping chemicals into a southern river to try to neutralise a toxic spill and contain the second environmental disaster to hit the country in as many months, a local official and state media said on Friday.

The cadmium-containing slick, which has cut tap water for tens of thousands of people downstream for five days, was flushed into the North River running across Guangdong province north to south from a Shaoguan zinc smelter last week.

The government has already lowered dam gates at the Baishiyao hydropower plant near Yingde, 90 km (54 miles) downstream from Shaoguan, to try to stall and dilute the pollutants.

Now it is to dump chemicals into the water, Yingde government spokesman Huang Zhensheng told Reuters by telephone.

"With only 1,200 tonnes of the chemicals, toxicity can be reduced by 30 percent," the Southern Metropolis News quoted an expert as saying.

Cadmium, a metallic element widely used in batteries, can cause liver and kidney damage and lead to bone diseases. Compounds containing cadmium are also carcinogenic.

In China's northeast, the front of a slick of benzene compounds that poisoned drinking water for millions after a chemical plant blast last month has crossed the Russian border through the frozen Amur River.

China apologised again to Russia on Thursday, while Russia's far east city of Khabarovsk readied alternative water supplies, though taps had not been turned off.

"Analysis of the water showed that the benzene content does not exceed ... the maximum allowable concentration," RIA-Novosti news agency quoted an Emergencies Ministry official as saying.

"As a result, the city authorities have decided not to turn off the Khabarovsk water supply."

Source: Reuters