China?s southern Guangdong province scrambled to protect its water supplies yesterday as a toxic waste spill from a zinc smelter flowed along a major river toward several sprawling cities, state media reported. It is the second environmental disaster to hit the country in as many months after an explosion at a chemical plant in the northeast poisoned drinking water for millions and sent a frozen, poisonous slick heading slowly but surely toward Russia.

Cadmium levels had been found to be 10 times normal in the Shaoguan city section of the North River cutting across Guangdong province north to south after the smelter?s discharge of waste during an equipment maintenance last week. Several villages and factories near Yingde, a city 54 miles downstream from Shaoguan, had been without running water for days, Xinhua news agency said yesterday. At a suburban Yingde cement plant, fire engines had been dispensing drinking water to thousands of workers and their families, Xinhua said.

?Taps are only on for showers in the evening for a couple of hours. We?ve been collecting drinking water with plastic buckets from fire engines since Sunday,? a worker surnamed Lu told Reuters by telephone. The city has shifted to a nearby reservoir to draw drinking water for its 100,000 residents, Xinhua said. 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.

The most-polluted stretch of water has arrived at Shakou township, 30 km upstream from Yingde, and dam gates at the nearby Baishiyao hydropower plant had been lowered to stall it, a local government spokesman told Reuters by telephone. ?We want to dilute the toxins there by reservoirs further upstream increasing discharges and then flush them quickly past Yingde,? the spokesman, surnamed Wang, said. ?But we are still waiting for the experts to decide when to do that.?