According to US national survey, The Environmental Working Group, 31 US cities get the tap water which is said to contaminated by a cancer causing chemical, Hexavalent chromium.
Their results on this study were released on Monday, Dec 20. They found that highest concentrations of hexavalent chromium, also known as chromium 6, in the drinking water in Norman, Okla., Honolulu and Riverside, California.
The levels ranged from 12.9 parts per billion in Norman to 0.03 ppb in Cincinnati and Boston, the Christian Science Monitor reported.
Residents sued, and in 1996 PG&E paid a $333 million settlement to about 600 people who blamed exposure to the chromium 6 for high rates of cancer and other diseases.
The average contamination in the cities surveyed was .18 ppb. That's three times the ideal standard under consideration by California's Office of Environmental Health Hazard Assessment.
Some researchers have claimed that the risks are negligible when the substance is ingested. Still, in 2009, National Toxicology Program scientists reported that their research "clearly demonstrates" that the compound is a carcinogen, substance responsible for cancer, in drinking water.
- IANS Inputs