Toxic Substance Found in Many Cities’ Drinking Water

Toxic substance found in many cities' drinking waterHexavalent chromium, a possible carcinogen made famous by the movie "Erin Brockovich," has been found in the drinking water of many U.S. cities, often in relatively high concentrations.

California attempted to regulate the concentration of hexavalent chromium in the state's drinking water in 2009, following a 2008 report by the National Institutes of Health, which named the substance as a "possible carcinogen," the Washington Post reports. The state proposed a goal of 0.06 parts per billion.

The Environmental Working Group's study found the chemical in the tap water of 31 out of the 35 cities sampled nationwide. Twenty-five of the 35 cities had levels of hexavalent chromium that exceeded the level proposed by California. The highest concentrations of the substance were found in Norman, Oklahoma, where the level of the possible carcinogen in the tap water was nearly 200 times California's goal level, the news source reports.

According to the U.S. Centers for Disease Control and Prevention, hexavalent chromium is a possible carcinogen when dissolved in water and can also cause or increase the risk of sustaining a number of medical conditions when inhaled, including lung cancer, skin issues, nasal cancer, perforated eardrums, kidney damage and liver damage.