Tap water in a Chinese city was found to contain excessive levels of the toxic chemical benzene, prompting residents to rush to buy bottled water, state media said on Friday.
Tests conducted on Thursday and Friday showed that tap water in Lanzhou, the capital of northwestern Gansu province, had as much as 200 micrograms of benzene per litre, 20 times the national limit, the official Xinhua news agency said, citing local environment authorities.
Benzene is an aromatic, colourless liquid and a basic raw material used in the petrochemical industry. Human exposure to the chemical increases the risk of cancer and other illnesses.
Part of the city suspended its tapwater supply and residents hurried to supermarkets to snap up bottled water, the state China News Service said.
Lanzhou's environmental protection bureau said it is investigating the source of the pollution and that more sample tests are planned.
Supplier Veolia Water said the contamination may have come from chemical-plant emissions, rather than pollution in the Yellow River that runs through the city, the report said.
Many waterways in China have suffered heavy contamination of toxic waste from factories and farms—pollution blamed on more than three decades of rapid economic growth and lax enforcement of environmental protection laws.
In February 2012, a cargo ship spilled acid into the Yangtze, China's longest river, tainting tap supplies and sparking a run on bottled water.
The accident came a month after a more serious environmental scandal in the southwestern region of Guangxi, where factories contaminated water supplies serving millions of people with toxic cadmium and other waste.
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