Tuesday, 31 January 2012

Cadmium spill on Longjiang River threatens water supplies to several Chinese cities.

On 15 January 2012 authorities in Guangxi Province in Southern China detected high levels of cadmium metal in the Longjiang River, after investigating reports of hundreds of dead fish in Hechi City. Cadmium levels were reported to be about 0.025 mg/l­ˉ³ (0.025 milligrams per liter) five times the official permitted safety levels. Cadmium, which is used in batteries, poses a serious threat to health; it is a carcinogen and can cause damage to the kidneys, liver, respiratory system and skeleton, and can be a persistent pollutant in water systems as it is hard to flush out. As well as Hechi the spill threatens the water supplies of Luijiang and Luizhou cities, with populations of 1.5 and 3.7 million respectively. There are reports of panic-buying of bottled water in Luijiang, and it is unclear if the 350 000 tons of water held in underground reserves at Luizhou would be enough to ride out the crisis. At the time of writing there have not been any reports of poisoning due to the incident.

The location of the Longjiang River, with the area effected by the spill highlighted in red. Zhang Ye/China Daily.

Authorities responded by releasing 500 million cubic meters of water from the Honghua Hydropower Station and mobilizing Police and Army personnel to pour polyaluminium chloride into the river as a neutralizing agent.

Officers from the Liuzhou brigade of the Armed Police Force pouring polyaluminium chloride into the Lomgjiang River on 29 January 2012. Xinhua News Agency.

On 25 January officials began investigating the Guangxi Jinhe Mining Co. in Hechi as the most likely source of the contamination. The company mines zinc in the city, and has failed repeatedly failed government inspections of its waste disposal procedures. Since cadmium is a common by-product of zinc mining the mine was an obvious target for suspicion. However 31 January local environment officials released a statement to the effect that they had arrested seven executives from chemical plants in Guangxi. It is unclear if this means the Jinhe Mine has been exonerated, if the investigation has been widened, or if officials are being deliberately vague to avoid prejudicing any future prosecution. Officials have also reported that seven mines and factories in have been closed as a precaution.

An environment official collecting samples from the Longjiang River in Luizhou. Reuters.

In the past three decades China has undergone an unprecedented process of industrialization, and has suffered many environmental problems as a consequence. In the past environmental groups have accused the country of turning a blind eye to environmental issues, in order to promote economic growth. However in the past few years Chinese authorities have shown signs of taking the environment much more seriously, after a string of pollution incidents with health implications, which have lead to public outcries.

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