Beijing (AsiaNews) - Residents in Lanzhou, the capital of the northwestern Chinese province of Gansu, swarmed supermarkets to buy bottled water after city authorities warned that the city's drinking water contained excessive levels of a carcinogenic chemical.
Tests taken in the morning showed in fact that benzene levels had reached 200 micrograms per litre - 20 times the national safety limit.
The industrial chemical, when ingested through food or drinks, can cause vomiting, dizziness, convulsions and even death in large enough doses.
To help allay public fears, the government said carbon filtering was being used to absorb the compound, and insisted the tap water was safe for "household uses other than drinking".
However, Du Sha, a Greenpeace toxins specialist, said that benzene was harmful even by indirect contact.
"The level of the benzene was already 20 times the national safety limit [. . .] tap water is not only unsafe for drinking, it will also irritate eyes and skin when used for washing," Du explained.
The water supply company is majority owned by the city government, but the daily operations are run by British firm Veolia Water, which holds a 45 per cent stake.
According to the company, the problem is due to a chemical factory that spilled sewage into a channel near one of water plants.
In China, widespread pollution is a problem strongly felt by the central government; however, attempts to reduce it have come up against the need to maintain a high level of industrial production.
On several occasions, Beijing said that it would counter industrial and agricultural pollution, a problem that affects large areas of the nation.
However, official reassurances have fallen short of expectations most of the time, partly because local officials are more interested in promoting the economy and reaping greater profits than in preserving the environment for future generations.