Cancer-causing hexavalent chromium found in 89 percent of cities sampled EWG (Environmental Working Group).
Laboratory tests commissioned Environmental Working Group (EWG) have detected hexavalent chromium, the carcinogenic “Erin Brockovich chemical,” in tap water from 31 of 35 American cities. 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 California regulators.
In 2009, California officials proposed setting a “public health goal” for hexavalent chromium in drinking water of 0.06 parts per billion (ppb) to reduce cancer risk. This was the first step toward establishing a statewide enforceable limit. Despite mounting evidence of its toxic effects, the EPA has not set a legal limit for hexavalent chromium in tap water nationally and does not require water utilities to test for it. In 25 cities where EWG’s testing detected chromium-6 — in the first publicly available national survey for the contaminant — it was found in concentrations exceeding California’s proposed maximum, in one case at a level more than 200 times higher.
At least 74 million Americans in 42 states drink chromium-polluted tap water, much of it likely in the cancer-causing hexavalent form. Given the scope of exposure and the magnitude of the potential risk, EWG believes the EPA should move expeditiously to establish a legal limit for chromium-6 and require public water suppliers to test for it.
Millions of Americans drink chromium-contaminated water
EWG’s investigation is the broadest publicly available survey of hexavalent chromium to date. The 31 cities with chromium-polluted tap water draw from utilities that collectively serve more than 26 million people. In California, the only state that requires testing for hexavalent chromium, water utilities have detected the compound in tap water supplied to more than 31 million people, according to an EWG analysis of data from the state water agency (EWG 2009).
EWG's tests provide a one-time snapshot of chromium-6 levels in 35 cities. But chromium pollution is a continuous, ongoing problem, as shown the annual water quality reports that utilities must produce under federal law. Over the years, nearly all of the 35 cities tested EWG regularly report finding chromium (in the form of total chromium) in their water despite using far less sensitive testing methods than those used EWG.
The total number of Americans drinking tap water contaminated with this compound is likely far higher than is indicated EWG's tests. At least 74 million people in nearly 7,000 communities drink tap water polluted with “total chromium,” which includes hexavalent and other forms of the metal, according to EWG’s 2009 analysis of water utility tests from 48,000 communities in 42 states (EWG 2009).
The EPA has set a legal limit in tap water for total chromium of 100 ppb to protect against “allergic dermatitis” (skin irritation or reactions). Measures of total chromium include the essential mineral trivalent chromium, which regulates glucose metabolism, as well as the cancer-causing hexavalent form. Preliminary EWG-commissioned water tests found that in most cases, the majority of the total chromium in water was in the hexavalent form, yet the EPA’s legal limit for total chromium is 1,700 times higher than California's proposed public health goal for hexavalent chromium. This disparity could indicate significant cancer risk for communities drinking chromium-tainted tap water.
The EPA’s new analysis of hexavalent chromium toxicity, released in draft form in September 2010 (EPA 2010a), cites significant cancer concerns linked to exposure to the contaminant in drinking water. It highlights health effects documented in animal studies, including anemia and damage to the gastrointestinal tract, lymph nodes and liver.