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Chromium 6 in U.S. Tap Water

Chromium 6 

In their recently published study on hexavalent chromium (chromium 6), the Environmental Working Group (EWG) found that 31 of the 35 U.S. cities that they tested have “measurable levels of hexavalent chromium,” which indicates that “American tap water may be widely contaminated with this potent toxic substance.” Four of the 35 cities that tested positive for hexavalent chromium are located in California, including “Riverside (1.69 ppb), San Jose (1.34 ppb), Los Angeles (0.20 ppb) and Sacramento (0.16 ppb).” Hexavalent chromium is a known carcinogenic chemical. It was made famous in the movie Erin Brockovich, starring Julia Roberts, that tells the true story of the cancer-stricken community in Hinkley, California that won a settlement from Pacific Gas and Electric Co. for contaminating their local tap water supply with hexavalent chromium. Facts from the study:  

  • At least 74 million Americans in 42 states drink chromium-polluted tap water, much of it likely in the cancer-causing hexavalent form.
  • The highest levels were in Norman, Okla.; Honolulu, Hawaii; and Riverside, Calif. In all, water samples from 25 cities contained the toxic metal at concentrations above the safe maximum recently proposed by California regulators.
  • The National Toxicology Program has found that hexavalent chromium in drinking water shows clear evidence of carcinogenic activity in laboratory animals, increasing the risk of otherwise rare gastrointestinal tumors (NTP 2007, 2008).
  • Levels of the carcinogen in 25 cities tested by EWG were higher than California’s proposed public health goal.
  • Studies in both animals and people show that exposure to hexavalent chromium via drinking water leads to elevated chromium levels in tissues, particularly the gastrointestinal tract, blood, liver, kidneys and spleen, and in increased toxicity (Kerger 1996; Finley 1997; Anderson 2002; NTP 2008; EPA 2010a).
  • Chronic exposure to hexavalent chromium in tap water is likely to raise everyone’s risk of cancer, but the young and the medically impaired may be especially vulnerable.
  • Hexavalent chromium (or chromium-6) gets into water supplies after being discharged from steel and pulp mills as well as metal-plating and leather-tanning facilities. It can also pollute water through erosion of soil and rock.

To read the full study, you can find the EWG’s report here: http://www.ewg.org/chromium6-in-tap-water  

ABOUT THE ENVIRONMENTAL WORKING GROUP The Environmental Working Group (EWG) is a non-profit public health and environmental research and advocacy organization, focusing on an array of public health and environmental issues including chemical contamination of food, water, consumer products and the environment.

Photo Credit: Environmental Working Group