Water Treatment Contaminants: Forgotten Toxins in American Water

Renee Sharp and J. Paul Pestano ewg.org Water treatment plants along the East Coast are struggling to recover from Superstorm Sandy, whose torrential rains washed tens of millions of gallons of raw or partially treated sewage into waterways. The less dramatic but equally urgent story: inside those waterworks, and others across the nation, chlorine, added as a disinfectant to kill disease- causing microganisms in dirty source water, is reacting with rotting organic matter like sewage, manure from livestock, dead animals and fallen leaves to form toxic chemicals that are potentially harmful to people. This unintended side effect of chlorinating water to meet federal drinking water regulations creates a family of chemicals known as trihalomethanes. The Environmental Protection Agency lumps them under the euphemism “disinfection byproducts” but we call them what they are: toxic trash. The EPA regulates four members of the trihalomethane family, the best known of which is chloroform, once used as an anesthetic and, in pulp detective stories, to knock out victims. Today, the U.S. government classifies chloroform as a “probable” human carcinogen. California officials consider it a “known” carcinogen. Three other regulated trihalomethanes are bromodichloromethane, bromoform, and dibromochloromethane. Hundreds more types of toxic trash are unregulated. Scientists suspect that trihalomethanes in drinking water may cause thousands of cases of bladder cancer every year. These chemicals have also been linked to colon and rectal cancer, birth defects, low birth weight and miscarriage (NHDES 2006). When Does Water Treatment Contamination Reach the Danger Point? An Environmental Working Group analysis of water quality tests conducted in 2011 and made public last year by 201 large American municipal water systems in 43 states has determined that each of these systems detected thihalomethane contamination. In short, more than 100 million Americans served by these large waterworks were exposed to toxic trash. Only one of the systems studied by EWG – Davenport, Iowa – exceeded the EPA rule barring more than 80 parts per billion of trihalomethanes in drinking water (see Appendix). This legal limit was set in 1998, based on the potential for trihalomethanes to cause bladder cancer. The 80-parts-per-billion standard was part of a major Clinton administration initiative to improve federal drinking water protections under the federal Safe Drinking Water Act. Yet the significant toxicity of trihalomethanes and other water contaminants generated by water treatment chemicals, documented by large numbers of scientists around the world, makes a compelling case for lowering the federal legal limit to well below 80 parts per billion. Since 1998, the evidence implicating trihalomethanes in serious disorders has mounted: In 2011 a French research team, pooling data from studies in France, Finland and Spain, found that men exposed to more than 50 parts per billion of trihalomethanes had significantly increased bladder cancer risks (Costet 2011). In 2007, a scientific team in Spain associated exposure to trihalomethanes greater than 35 parts per billion with increased bladder cancer risks (Villanueva 2007). In 2007, researchers from four Taiwanese universities reported that people faced twice the odds of dying from bladder cancer if they drank water with trihalomethane contamination greater than 21 parts per billion. This study was cited in the 2011 National Report on Carcinogens, a Congressionally-mandated report produced by the National Toxicology Program, a federal interagency scientific body (Chang 2007, NTP 2011). A 2010 study by the National Cancer Institute found that about a quarter of the human population may have a genetic susceptibility that raises its risk of bladder cancer from trihalomethanes (Cantor 2010). to read more click here: ewg.org