Four officials at a chemical plant in north China's Shanxi Province have been sacked and 122 chemical companies along the Zhuozhang River ordered to suspend operations after the plant leaked nearly 9 tons of aniline into the river, affecting downstream cities in neighboring Hebei and Henan provinces.

People line up to get water from fire engines mobilized to bring water to residents in Handan yesterday after the city government cut off water supplies on Saturday.[Photo/China Daily]

Water in the Yuecheng Reservoir and the Red Flag Canal of Anyang City in central China's Henan Province had been tested for excessive aniline and volatile phenol after the pollution in Shanxi, said an announcement released by the Anyang government.

An initial investigation revealed that a loose drainage valve in the plant owned by the Tianji Coal Chemical Industry Group in Lucheng City was to blame for the leak. It was spotted by plant employees on the morning of December 31, Xinhua news agency reported.

The Shanxi provincial government said it received a report on Saturday, and an emergency response had been initiated to stop the leak and clean up the pollutants. Another 30 tons of aniline had been contained in a nearby disused reservoir, the local emergency response headquarters said.

Chen Jianwen, the Tianji group's general manager, Ren Yongjie, the group's deputy manager in charge of work safety, and two heads of the plant's storage workshop were sacked, the Shanxi provincial environmental bureau said.

A large amount of dead fish was seen in the upper reaches of the Zhuozhang river on Friday evening, according to the emergency water supply headquarters in the city of Handan, on the river's lower reaches in Hebei Province.

When the Handan government was informed of the accident by authorities in Changzhi, which administers Lucheng, on Saturday afternoon. it shut off the city's water supplies.

However, supplies in most parts of downtown Handan had resumed by noon yesterday, after the local government switched to an alternate underground source.

Fire engines have also been mobilized to bring water to the city's residents and 66,000 bottles of mineral water have been bought in from other cities. Authorities did not say how many households were affected.

Changzhi officials said there had been no reports of casualties so far, and water quality in the river was improving.

Concentrations of aniline in the river have decreased to 2.15mg per liter from the previous level of 72mg per liter, according to data from a monitoring station on the river.

However, the concentration should be less than 0.1mg per liter, according to national standards.

"Since the pollutants won't decompose easily, it will likely take weeks to solve the problems caused by the spill," Zhang Xiaojian, a professor at the environmental school of Tsinghua University, told Xinhua.

Aniline, a toxic chemical widely used in the pharmaceutical industry, can cause serious damage to internal organs, such as the kidneys and liver.

China has witnessed major pollution incidents due to local governments and enterprises' excessive pursuit of economic benefits and neglect of pollution control, Wang Yinghui, professor at Guangxi University's college of environment, told Xinhua.

Deficiencies in emergency mechanisms to handle environmental incidents at some local governments worsen the pollution problem, Wang added.

Industrial contamination is to blame for China's environmental pollution due to the country's rapid economic growth, said E Xueli, a researcher with the China Disease Prevention and Control Center.

Many large factories had been built along rivers at a small cost and with comparatively little fines for their pollutant discharge or leakages, he said.

Continuous incidents should sound an alarm to local governments and enterprises, E said.