Investigators identified a crude oil pipeline run by state-owned China National Petroleum Corp as the source for polluting the water supply in a north-western city, state media reported Saturday, according to dpa. The public water supply for 2.4 million people in the north-western Chinese city of Lanzhou was Friday polluted by benzene. The level of benzene was 200 micrograms per litre, or 20 times the national limit, and nearly double the 118 micrograms per litre detected late Thursday, the Xinhua news agency reported. The contamination caused panic among residents of the capital city of Gansu province on Friday, as supermarkets ran out of bottled water. Residents fetched water in pots, basins and buckets until after midnight as fire engines and water sprinklers brought in emergency supplies. The city government warned citizens not to drink tap water for 24 hours until 11 am Saturday. Later in the day, the government said the toxic pollutant was no longer detected in four samples taken from two central districts, but that "traces" of benzene were still found in Xigu and Anning districts. Benzene is a colourless petrochemical that is used as a solvent for making plastics and other products. It is carcinogenic if ingested. Lanzhou, an inland city on the Yellow River, is well-known for its chemical industries and its associated air and water pollution.
