Pei Ziyao, 3, stands in line with his mother to receive water from a distribution center in Harbin yesterday. The government is providing 20 kilograms of drinking water to every household after a chemical plant explosion polluted the city's main supply source. [Photo: Jian Guangzhou]

An extensive cleanup operation is under way in northeast China's Heilongjiang and Jilin provinces as an 80-kilometer slick of polluted water rolls down the Songhua River.

Environmental experts are opening reservoirs in an effort to dilute some 100 tons of dangerous chemicals—primarily benzene—that were released in a chemical plant explosion on November 13.

Huge quantities of absorbent carbon were also being brought in for use in purification.

Meanwhile, cities along the Songhua that use the river as their source for drinking water have shut down municipal systems and are distributing water drawn from wells, digging new wells and trucking in supplies from neighboring areas to millions of thirsty residents.

The hardest hit city is Harbin, provincial capital of Heilongjiang, where 3.8 million people won't be able to turn on their taps for days.

The effects of the chemical spill are so widespread that China is keeping in close contact with Russia, which fears its own waterways might become tainted.

The polluted water is expected to flow into the Heilong River on the Sino-Russian border in around 14 days, China's environmental authority said yesterday in Beijing.

Foreign Ministry spokesman Liu Jianchao told a news conference in Beijing yesterday that China has apprised Russia of the pollution situation and has pledged to do everything it can to minimize the effects of the spill across the border.

"China is very concerned about the possible hazards to Russia and has updated its neighbor several times about the pollution," Liu said.

"Both countries have pledged to cooperate closely to handle the pollution."

Zeng Yukang, deputy general manager of the China National Petroleum Corp, expressed his "sincere sympathy and deep apologies" to the residents of northeast China for the pollution caused by an explosion in a chemical plant under CNPC Jilin Petrochemical Co.

Zeng traveled to Harbin on Wednesday at the head of a drilling crew that plans to dig 100 deep groundwater wells for universities and colleges and water and heat suppliers in the city.

He said it is CNPC's duty to help treat the pollution.

The blast, which occurred in Jilin City, Jilin Province, killed five people and injured 70, before unleashing tons of dangerous chemicals into the Songhua River.

Harbin Mayor Shi Zhongxin said city government will try to restore the tap water supply in four days.

On the cleanup front, two reservoirs along the Songhua River increased their water discharges yesterday in an effort to dilute the chemical slick.

More than 1,000 tons of absorbent carbon were expected to arrive in Harbin today to help meet the city's water purification needs.