An 80-kilometer swathe of polluted water in the Songhua River was expected to reach Harbin City's water supply at about 5 AM today, according to local officials yesterday giving their first detailed explanation for the taps there being cut off.

The worst stretch of contaminated water will pass the capital of northeast China's Heilongjiang Province on Saturday morning, said a provincial environment protection bureau official.

On Wednesday, the State Environment Protection Administration confirmed that pollutants containing benzene and nitrobenzene had contaminated the river after a chemical-plant blast in its upper reaches, leaving a trail of dead fish.

The explosion on November 13 in Jilin City, in neighboring Jilin Province, had forced Harbin to announce that it would cut off its water supply for four days from Tuesday midnight. The city of 3.8 million people relies largely on the Songhua for its water and is situated on its middle reaches.

On November 20, a water-monitoring station in Zhaoyuan County on the provincial border found that levels of the two chemicals were much higher than State limits, said Li Ping, Heilongjiang environmental bureau spokesperson.

At one time, the nitrobenzene level was 103.6 times higher than normal; and the contaminated belt of water was flowing at about 2 kilometers per hour, the bureau said.

Zhang Lanying, director of Jilin University's Environment and Resources Institute, said that benzene, which does not dissolve in water, is a dangerous substance.

"Massive amounts can lead to the disorder of blood cells; in other words, leukemia," she said.

"Harbin's move to cut off the water supply was not a knee-jerk reaction, "she added. "If the contaminated water had been supplied to households, the result would have been unimaginable."

To speed up the flow of the river and dilute the contamination, Jilin City has increased the water discharge volume of Fengman Hydroelectric Power Plant, said a spokesperson.

As for cities and counties downstream of Harbin, 90 percent rely on groundwater as their main water source, said Dong Shuhua, director of Heilongjiang Water Information Bureau. "They will not be very much affected."

In Harbin, the panic buying of water and attempts to get out of the city were not as frantic on Wednesday as they had been in previous days, according to today's China Daily.

Adding to residents' relief was 15 hours of water supply to parts of the city and availability of bottled water in shops and supermarkets.

Zhao Wanxia, a salesperson, said she had stored enough water to last for a few days. "I first wash vegetables, then use the water to clean the floor or flush the toilet."

More than 16,000 tons of bottled water was being transported to Harbin from neighboring cities including 10 train carriages carrying 1,000 tons from Shenyang, capital of northeast China's Liaoning Province.

The city's 918 wells are all in operation and teams from Daqing Oilfield are drilling another 100, said Wang Zhengbang, deputy secretary of Harbin's municipal government.

The government has designated 10 hospitals to treat patients in case they drink contaminated water and earmarked 10 million yuan (US$1.2 million) to deal with emergencies and 1 million yuan (US$120,000) to help the poor, elderly and those living alone.

Wang urged residents to keep away from the riverbank for fear of contamination.

Despite the water being cut off, officials have assured residents of the normal operation of the city's heating system, but they told people yesterday not to take water from the system for household use.

(China Daily November 24, 2005)