When you pour yourself a glass of tap water or even take a shower, you may be among over 100 million Americans exposing yourself to carcinogenic, "toxic trash."

Watchdog organization Environmental Working Group (EWG) looked at 2011 water quality tests for over 200 municipal water systems that affect 100 million people in 43 states. 

In their analysis published Wednesday, the group documents that all the systems had water polluted with chemicals called trihalomethanes—chemicals caused when chlorine, used as a disinfectant, mingles with rotting organic matter such as farm runoff or sewage.

While the EPA refers to these trihalomethanes as "disinfection byproducts," EWG says they are "toxic trash."

Trihalomethanes have been linked to a range of health problems including bladder cancer, colon and rectal cancer, birth defects, low birth weight and miscarriage.

While only the municipal water system of Davenport, Iowa showed levels that exceeded the upper legal limit the EPA established in 1998 of 80 parts per billion of trihalomethanes in drinking water, EWG points to multiple studies showing an increased risk of bladder cancer caused by much lower levels of trihalomethanes.

“New science makes a compelling case for stronger regulations and a stricter legal limit,” said Renee Sharp, a senior scientist at EWG and co-author of the analysis.

Further, EWG's analysis notes that the levels of this "toxic trash" recorded are for annual averages, but there are likely contamination spikes, something of particular danger for pregnant women.

“Many people are likely exposed to far higher concentrations of trihalomethanes than anyone really knows,” stated Sharp.  “For most water systems, trihalomethane contamination fluctuates from month to month, sometimes rising well beyond the legal limit set by the federal Environmental Protection Agency.”

The problem with trihalomethanes arises because water treatment facilities are forced to deal with contaminants to begin with, so EWG says improvements, which are ultimately less costly, must be made to have cleaner source water.

Among EWG's recommendations:

• Congress should reform farm policies to provide more funds to programs designed to keep agricultural pollutants such as manure, fertilizer, pesticides and soil out of tap water.     
• Congress should renew the “conservation compliance” provisions of the 1985 farm bill by tying wetland and soil protection requirements to crop insurance programs, by requiring farm businesses that receive subsidies to update their conservation plans and by strengthening the government’s enforcement tools.
• Congress must allocate significant money to help repair and upgrade the nation’s water infrastructure.     
• Source water protection programs should be significantly expanded, including efforts to prevent or reduce pollution of source waters and to conserve land in buffer zones around public water supplies. Financial support for these projects is crucial.

Read the full report here (pdf).

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