Chromium in drinking water shown to cause cancer
A chemical found in drinking water causes malignant tumours in lab animals, the US National Institutes of Health said following a two-year study, suggesting the chemical could be behind human cancers.Scientists found a "significant increase in tumours" in mice and rats given water contaminated with Hexavalent Chromium, a widely used industrial chemical.
Hexavalents Chromium, or Chromium-6, came into public view through the film "Erin Brokovich" about an environmental campaigner's struggle to win compensation for people suffering from cancers in an area of contaminated drinking water.
Chromium-6 has so far only been officially recognised as a carcinogen when inhaled. The chemical is widely present in industrial applications such as electroplating, leather tanning, and textile manufacturing, but has also been found in some drinking water sources.
"Previous studies have shown that hexavalent chromium causes lung cancer in humans in certain occupational settings as a result of inhalation exposure," said Michelle Hooth, who worked on the NIH study. "We now know that it can also cause cancer in animals when administered orally," she said.
"We found that hexavalent chromium is absorbed from the gastrointestinal tract. After it is orally administered, it is taken up by the cells in many tissues and organs."
Mice and rats developed malignant tumours not normally found in laboratory animals, such as cancers of the oral cavity and of the intestines.
The doses of chromium-6 were ten times higher than those present in drinking water in the Brokovitch case but show a clear link between ingesting the chemical and developing cancers of parts of the digestive system.
Erin Brokovich, the campaigner who the May 2000 film is based on, said there were dozens more potentially contaminated sites across the US and that it was "high time" the chemical was recognised to cause cancer by ingestion.