Excessive levels of cancer-linked chemicals found in drinking water for 6mn Americans

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Drinking water for six million Americans contains chemicals linked with cancer, hormone disruption and obesity at levels that exceed what is deemed safe by the federal government, according to a Harvard study.

Water samples taken by the US Environmental Protection Agency (EPA) near industrial sites, military fire training locations, airports, and wastewater treatment plants contain levels of the toxic chemicals polyfluoroalkyl and perfluoroalkyl (PFASs) that go beyond what is considered safe by the federal government, according to a new study by researchers at Harvard's T.H. Chan School of Public Health and John A. Paulson School of Engineering and Applied Sciences.

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The Harvard researchers analyzed data related to the detection of six types of PFASs in approximately 36,000 toxic drinking water samples collected by the EPA from 2013 to 2015. The drinking water involved in the EPA's samples applies to around two-thirds of the US, researchers said.

PFASs have been used in the last 60 years to develop a wide range of industrial and commercial products, researchers said. And though many top manufacturers have ended their use based on high levels of toxicity, PFASs remain present in watersheds and elsewhere around the nation.

"For many years, chemicals with unknown toxicities, such as PFASs, were allowed to be used and released to the environment, and we now have to face the severe consequences," said Xindi Hu, a doctoral student at Harvard and the study's lead author.

"In addition, the actual number of people exposed may be even higher than our study found, because government data for levels of these compounds in drinking water is lacking for almost a third of the U.S. population—about 100 million people."

PFASs were detected at minimum reporting levels required by the US government in 194 of 4,864 drinking water supplies in 33 states, the researchers found. 

At least one water sample from each of 66 drinking water supplies, which apply to six million people in the US, measured at or beyond what the EPA considers safe for the PFASs perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA).

Thirteen states were responsible for 75 percent of the toxic detections. The states with the highest level of detection included California, New Jersey, North Carolina, Alabama and Florida. PFASs were detected in water supplies of nearly the entire area of New Jersey, according to the study.

"These compounds are potent immunotoxicants in children and recent work suggests drinking water safety levels should be much lower than the provisional guidelines established by EPA," said Elsie Sunderland, senior author of the study and associate professor at the Harvard schools involved in the research.

The study, titled "Detection of Poly- and Perfluoroalkyl Substances (PFASs) in U.S. Drinking Water Linked to Industrial Sites, Military Fire Training Areas, and Wastewater Treatment Plants," was published Tuesday in Environmental Science & Technology Letters.