Hexavalent chromium (a.k.a. hex chrome or chromium-6) is a metal used in a number of industrial processes, including chrome plating, steel production, paint, cement making, metal working, and many others. Until recently, chromium compounds were widely used as a wood preservative in pressure-treated wood. Hexavalent chromium exposure, which has been linked to cancer, is caused by breathing contaminated air and, as in the case made famous by Erin Brockovich, drinking contaminated tap water.
Hexavalent chromium is considered a human carcinogen, which means that exposure to this metal increases your risk of cancer. Inhaling this compound over an extended period of time can cause lung and nasal cancers. Other hexavalent chromium health effects include airway irritation, nasal and skin ulcers and lesions, perforation of the nasal septum, asthma, dermatitis and other allergic reactions. Hexavalent chromium in water can cause stomach and intestinal damage and can lead to cancer. In lab animals, this metal damages sperm and male reproductive systems, and in some cases, has damaged developing fetuses.
People can be exposed to hexavalent chromium by breathing contaminated air in or around the workplace or hazardous waste sites, ingesting or inhaling contaminated soils, or drinking contaminated tap water. In monitoring conducted by the California Department of Public Health, nearly 40% of drinking water sources tested in California contained unsafe levels of hex chrome.
The Environmental Working Group released a report in December 20, 2010, indicating that millions of Americans are regularly drinking hexavalent chromium in water, a problem made famous in the 2000 film "Erin Brockovich."
The group – whose study was first reported in a story by Lyndsey Layton in the Washington Post – tested water from 35 U.S. cities and found that samples from 31 cities contained hexavalent chromium. The highest concentrations were found in Norman, Okla.; Honolulu; and Riverside, Calif. The substance had been a widely used industrial chemical for decades and has evidently leached into the groundwater in many areas.
The EWG report states:
Despite mounting evidence of the contaminant's toxic effects, the U.S. Environmental Protection Agency (EPA) has not set a legal limit for chromium-6 in tap water and does not require water utilities to test for it. Hexavalent chromium is commonly discharged from steel and pulp mills as well as metal-plating and leather-tanning facilities. It can also pollute water through erosion of natural deposits.
The authoritative National Toxicology Program (NTP) of the U.S. Department of Health and Human Services has said that chromium-6 in drinking water shows 'clear evidence of carcinogenic activity' in laboratory animals, increasing the risk of gastrointestinal tumors. Just last October, a draft review by the EPA similarly found that ingesting the chemical in tap water is 'likely to be carcinogenic to humans.' Other health risks associated with exposure include liver and kidney damage, anemia and ulcers.
Drinking-water supplies all over the country are increasingly tainted by chemicals used in natural gas drilling. And Erin Brockovich, for her part, told the EWG that she's rather astonished to find that hexavalent chromium is still a prospective health threat in so many communities.
"It is sometimes difficult to understand why I still have to warn the public about the presence of hexavalent chromium in drinking water 23 years after my colleagues and I first sounded the alarm," Brockovich told the EWG. "This report underscores, in fairly stark terms, the health risks that millions of Americans still face because of water contamination."
The list of cities found to have hexavalent chromium in the municipal water supplies are as follows:
If your city is not on that list, it doesn't mean that you don't have hexavalent chromium in your water supply. The best way to protect yourself and your family from hex chrome, as well as over 35,000 other potential "toxic cocktails" is with a good reverse osmosis system, especially the US Water Cobalt Hyper-Safe Reverse Osmosis System. This system is extremely effective in removing chromium 6 from water supplies, as well as a wide variety of other contaminants. Check out our page on Chromium-6 in Water for more information on treatment options.