美国自来水中发现致癌物

In the movie Erin Brockovich, Julia Roberts played a California woman on a mission against a local company accused of leaking the metal chromium-6 into ground water, allegedly causing cancer in 600 people.  The movie was based on a real story. The more than $300 million settlement was one of the largest ever in the United States.

Fifteen years later, test results by an environmental group produced shocking results about tap water across the country.     

In the study by the Environmental Working Group, 31 out of 35 cities showed various levels of Chromium-6, considered a carcinogen, in drinking water.    

Olga Naidenko is the Senior Scientist at the Environmental Working Group

"Our study was a snapshot which demonstrated that Chromium pollution in drinking water is widespread across the US," said Olga Naidenko is the Senior Scientist at the Environmental Working Group.  "Washington was 9 times higher than what California state scientists think is safe."

The Washington Aqueduct, owned and operated by the US government, provides potable water for a million people in the Washington DC region. Thomas Jacobus is General Manager.  He says the Aqueduct did not test specifically for Chromium-6. But once the tests were done, he says, the levels were low.

"The cost to remove chromium, half of a part per billion, would be staggering and the question is, is that practical and is that necessary?" asked Jacobus.

The Aqueduct runs tests for bacteria and contaminants. It regularly checks for 22 metals, but not chromium.  Jacobus says he is confident the water is safe.  

Chromium-6 is a naturally occurring metal. Chromium pollution most commonly comes from mining and other industrial processes.    

"It has been released into water because industries didn't care," said Naidenko.  "They don't do it on purpose, but for example they store industrial waste water in unlined pools, basically just dump it outside, that is how it often ended up in water."

Naidenko says 15 years after the California case, the Environmental group found similar levels of chromium-6 in other parts of the country.

"The highest sample of our study was actually within the range that Ms. Brockovich detected in Hinkley, California in a highly polluted area," added Naidenko.

Washington Aqueduct says much can happen as water travels to the consumer.  Jacobus says old pipes and fixtures can leach metals.  He says water treatment facilities were never designed to remove chemicals that are now showing up.

"Right now, I think it means we need to keep looking and be aware that there may be some things that we don't know," added Jacobus.

Toxic chemicals are showing up in water around the world.  Naidenko says in China, Greece and Scotland people have suffered from stomach cancers she says are linked to polluted water.

"We are not aware of studies that systematically analyze chromium in other countries, but reports from individual countries indicating chromium pollution is fairly common," noted Naidenko.

The U.S. Environmental Protection Agency has now ordered utilities around the US to test for chromium-6 twice a year. EPA has also begun a review of the impact of chromium-6 to determine safe levels in drinking water.