The carcinogenic chemical chromium-6 (or hexavalent chromium) has been found in the drinking water of 31 of 35 U.S. cities analyzed by the Environmental Working Group (EWG) which released results of its tests on December 20. Chromium-6 is the chemical made infamous in the movie “Erin Brockovich,” about the residents of Hinkley, California, who won $333 million in damages in 1996 from Pacific Gas and Electric for polluting their drinking water with chromium-6.
Chromium-6 is highly toxic and has been found to cause allergic dermatitis, and stomach and gastrointestinal cancer in animals and humans. Used in the manufacture of stainless steel, textiles, anticorrosion coatings, and in leather tanning, it gets into drinking water through industrial pollution. It is also present naturally in some minerals.
After the National Toxicology Program found that chromium-6 caused cancer in rats and mice in 2008, California proposed the establishment of a statewide legal limit of 0.06 parts per billion (ppb) of chromium-6 in drinking water. On December 31, the Office of Environmental Health Hazard Assessment of the California Environmental Protection Agency revised its proposed limit to .02 ppb because of new findings about the vulnerability of young children and sensitive populations to chromium-6 exposure.
The Environmental Protection Agency (EPA) has classified chromium-6 as “likely to be carcinogenic to humans” when ingested through drinking water in a draft review of the chemical, but it does not require water utilities to test for it nor has it established safe legal limits for the chemical.
In its tests, EWG found that 25 of the cities tested had levels of chromium-6 higher than California’s original proposed limit of .06 ppb; now all 31 cities with chromium-tainted water have levels higher than California’s new proposed limit of .02 ppb. The highest levels of chromium-6 were found in Norman, OK which measured 12.9 ppb; Honolulu, HA with 2.00 ppb; Riverside, CA at 1.69 ppb; Madison, WI at 1.58 ppb; and San Jose, CA which measured 1.34 ppb. The utilities that service the 31 cities whose tap water contained chromium-6 provide water to over 26 million people.
And in fact, EWG believes the actual number of people drinking chromium-6 contaminated tap water is much larger. According to its 2009 analysis of drinking water, 74 million people drink tap water polluted with “total chromium.” Total chromium includes trivalent chromium (which occurs naturally in many vegetables, fruits, meats, grains and yeast), as well as the toxic chromium-6. Preliminary tests have found that most of the total chromium in water is chromium-6, yet the EPA’s legal limit for total chromium is 100 ppb—5,000 times higher than California’s new proposed limit for chromium-6.
Currently California is the only state that requires testing specifically for chromium-6. In other states, water utilities only test for total chromium—and only measure amounts at or above 10 ppb, 500 times higher than California’s new proposed limit. However, on the heels of EWG’s findings, the EPA is urging, though not yet requiring, water utilities around the country to test for chromium-6. The agency will provide technical assistance to the 31 cities that were found to have chromium-6 contaminated water, as more sophisticated testing techniques are required. The EPA is now also studying whether it should set a limit for chromium-6 in drinking water. Lisa Jackson, EPA Administrator, said that once the reassessment is completed in 2011, EPA will likely “tighten drinking water standards to address the health risks posed by chromium-6.”
Meanwhile, if your drinking water contains chromium-6, the best way to filter it out is with reverse osmosis combined with a superior carbon filter. Bottled water is not a solution, since many types of bottled water are simply repackaged tap water.
If you’d like to find out what else might be in your drinking water, the EWG’s National Drinking Water Database is a compilation and analysis of approximately 20 million records from state water utilities in 45 states and the District of Columbia. During its investigation from 2004-2009, EWG found 316 contaminants in the water drunk by 256 million Americans in 48,000 communities. For the 114 contaminants regulated by the EPA, utilities met safety standards 92 percent of the time. But 202 of the contaminants are completely unregulated, and thus can be present in any amount. Among the contaminants found were 62 unregulated agricultural chemicals (fertilizers, pesticides, herbicides, CAFO runoff) and 35 regulated contaminants; 56 unregulated pollutants from sprawl and urban areas (auto emissions, road runoff, lawn pesticides, wastewater treatment chemicals) and 30 regulated ones; 127 unregulated industrial pollutants (industrial chemicals, plasticizers, solvents) and 78 regulated contaminants; and 24 unregulated water treatment contaminants (disinfection chemicals) and 18 regulated pollutants. Hundreds of thousands of people have in fact consumed pollutants in amounts over the drinking water health standards.
There is much that needs to be done to improve our country’s drinking water, including substantial infrastructure investment and stricter enforcement of the Clean Water Act. But the EPA should move quickly to strengthen the Safe Drinking Water Act by requiring water utilities to test for the currently unregulated contaminants and setting minimum health standards for them.