A crude oil leak from a pipeline owned by a unit of China National Petroleum Corp (CNPC) is to blame for water contamination that has affected more than 2.4 million people in the city of Lanzhou, media reported on Saturday.
Xinhua news agency cited Lanzhou environmental protection chief Yan Zijiang (閆子江) as saying that a leak in a pipeline owned by Lanzhou Petrochemical Co, a unit of CNPC, was to blame for the water contamination.
The leak poisoned the water source for a water plant, introducing hazardous levels of benzene into the city’s water, he told Xinhua.
On Friday, the level of the cancer-inducing chemical in Lanzhou’s tap water rose 20 times above national safety limits, Lanzhou authorities said in a statement. The high benzene levels forced the city to turn off the water supply in one district and city officials warned citizens not to drink tap water for the next 24 hours.
Yan told Xinhua on Saturday that the leak had been located and repairs were underway.
The Lanzhou City Government on Friday said it had detected 200 micrograms of benzene per liter of water, while China’s national safety standard is 10 micrograms.
By late Saturday morning, Xinhua said the benzene concentration at five of the six water monitoring sites had been confirmed safe.
The water supply company, Lanzhou Veolia Water Co, is majority-owned by the city government, with Veolia China, a unit of French firm Veolia Environment, holding a 45 percent stake.
On Friday, Veolia said in a statement that an initial investigation found the high levels of benzene were caused by contamination at one of the two culverts that transfer raw water from a sedimentation plant to the water treatment plant.
According to Xinhua, investigators found crude oil in the soil along a duct between two water works owned by Veolia Water.
“The channel has been carrying water to Veolia Water’s No. 1 and No. 2 plants for decades. Under this ditch lies Lanzhou Petrochemical’s oil pipeline,” Yan told Xinhua.
A Veolia spokeswoman in Hong Kong on Saturday declined to comment on the matter and referred all questions to city authorities.
Lanzhou, a heavily industrialized city of 3.6 million people in the northwestern province of Gansu, ranks among China’s most polluted regional hubs.
A spokesman for CNPC parent company PetroChina Co could not immediately be reached for comment.
Lanzhou Petrochemical is a major refinery in China’s landlocked northwest that has a total refining capacity of 280,000 barrels per day and plans to process 195,000 barrels of crude this year, industry sources have said.