Jan. 9 (Bloomberg) -- Local authorities in China's Hunan province are cleaning up a toxic spill from the nation's biggest zinc smelter that polluted a tributary of the Yangtze River, at least the third such incident in the past three months.
Cadmium, an industrial chemical that can cause neurological disorders and cancer, flooded into the Xiangjiang river during a silt-cleaning project started without official approval, the provincial environmental protection bureau said on its Web site yesterday. A spokesman for Zhuzhou Smelter said it isn't responsible for the accident and the plant is operating normally.
The cadmium level in the polluted stretch of river peaked at 25.6 times the safe standard on Jan. 5 before falling to 0.14 times on Saturday after the local government used neutralizing chemicals and turned up the flow of water from upstream reservoirs to dilute the toxins, according to the statement.
``The government has controlled the pollution and there has been no public panic,'' Jiang Yimin, head of the bureau, said in the statement. Drinking water supplies from plants in Xiangtan city near the site of the spill all met safety standards as of Jan. 7, the bureau said.
Seven out of 10 Chinese rivers are contaminated by toxins, according to the official Xinhua news agency. A nitrobenzene spill in the northeastern province of Jilin in November caused authorities to turn off the tap water of more than three million people, threatened supplies in neighboring Russia and prompted the resignation of China's environmental chief.
The cadmium spill in Hunan province polluted a 100-kilometer stretch of the Xiangjiang river, which flows past the provincial capital Changsha into Dongting Lake before entering the Yangtze, China's longest river, the state-run China Daily reported today.
Zhuzhou Water Conservancy Investment Co. on Dec. 23 started the silt-cleaning project without official permission and didn't take proper precautions, the bureau said in its statement.
The spill happened on Jan. 4 after the company built a dam at the mouth of a waste drainage pipe from the Zhuzhou Smelter, according to the bureau. The dammed water flowed into two lakes containing high levels of cadmium from nearby plants before overflowing into the river.
``Zhuzhou Smelter should not be responsible for the toxic spill incident,'' said Yu Feng, a spokesman with Hunan Zhuye Torch Metals Co., the Shanghai-listed owner of Zhuzhou Smelter. Yu said the plant is unlikely to be shut because of the spill.
Zhuye Torch shares rose 4.7 percent to 2.88 yuan at the 3 p.m. close local time on the Shanghai stock exchange.
The government will hold a province-wide inspection to stem any potential pollution accidents, the Hunan environmental protection bureau said.
The incident is the second in less than a month involving a zinc smelter. Shenzhen Zhongjin Lingnan Nonfemet Co., the country's third-biggest zinc producer, was ordered to halt output at its Shaoguan Smelter in Guangdong province on Dec. 21 after discharging excessive cadmium into a local river.
The spill prompted Yingde city, which has 100,000 residents on the Beijiang river, to close part of its water supply system for several hours on Dec. 20, the China Daily reported.
Cadmium is extracted during the production of zinc, used to strengthen steel for car bodies, and lead. Cadmium and lead are used in batteries.
China's economic growth, the fastest of any major economy, and an expanding urban population have caused an increase in pollution, aggravating social tensions and bringing the government's environmental management under scrutiny.
State Environmental Protection Administration head Xie Zhenhua resigned on Dec. 2 after being criticized by the State Council, the nation's highest ruling body, over the toxic spill in the northeast Songhua River. The spill followed an explosion at a unit of PetroChina Co., the nation's biggest oil company.
The environmental protection bureau ``hasn't paid due importance to the incident, underestimated the bad influence of the incident and should be responsible for the damage,'' state broadcaster China Central Television cited the State Council as saying.
At the same time, the environmental protection bureau criticized local officials for covering up the accident and for ``blind pursuit'' of economic development that has seriously damaged China's environment in the past 25 years.
In a further pollution incident, six tons of diesel leaked from an electricity factory into a branch of the Yellow River in the central province of Henan, the official Xinhua News Agency reported on Jan. 6. Cities along the Yellow River have been alerted to be cautious of the water quality, the report said.