CAMBRIDGE, Massachusetts, August 12, 2016 (ENS) – Public drinking water supplies for six million people in 33 states have tested higher than federal safety levels for a class of industrial chemicals linked to cancer and other health problems – polyfluoroalkyl and perfluoroalkyl substances – known in short as PFASs.
This conclusion comes from a new study led by researchers from the Harvard T.H. Chan School of Public Health and the Harvard John A. Paulson School of Engineering and Applied Sciences, or SEAS.
The study found that the fluorinated chemicals were detectable at the minimum reporting levels required by the U.S. Environmental Protection Agency in 194 out of 4,864 water supplies in 33 states.
Drinking water from 13 states accounted for 75 percent of the detections: California, New Jersey, North Carolina, Alabama, Florida, Pennsylvania, Ohio, New York, Georgia, Minnesota, Arizona, Massachusetts, and Illinois, in order of frequency of detection.
“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 lead author Xindi Hu, a doctoral student in the Department of Environmental Health at Harvard Chan School, Environmental Science and Engineering at SEAS.
“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,” said Hu.
PFASs have been used for 60 years in industrial and commercial products from food wrappers to clothing to pots and pans because they impart useful properties, including fire resistance and oil, stain, grease and water repellency.
These chemicals are found in cleaners, textiles, leather, paper and paints, fire-fighting foams, and wire insulation.
EPA is particularly concerned about so-called long-chain PFAS chemicals. These are persistent in the environment, bioaccumulative in wildlife and humans, and are toxic to laboratory animals and wildlife, producing reproductive, developmental, and systemic effects in laboratory tests.
These chemicals have been linked with cancer, hormone disruption, high cholesterol, and obesity, as well as being known to interfere with immune function.
Several major manufacturers have stopped using some PFASs, yet the chemicals persist in wildlife and in people, who often are exposed through their drinking water.
The Harvard researchers looked at levels of six types of PFASs in drinking water supplies, using data from more than 36,000 water samples collected nationwide by the EPA from 2013 to 2015.
They also looked at industrial sites that manufacture or use PFASs – at military fire-training sites and civilian airports where firefighting foam containing PFASs is used, and at wastewater treatment plants.
Discharges from wastewater treatment plants, which are unable to remove PFASs from wastewater by standard treatment methods, could contaminate groundwater. So could the sludge these plants generate, which is often used as fertilizer.
Sixty-six of the public water supplies examined, serving six million people, had at least one water sample that measured at or above the EPA safety limit of 70 parts per trillion (ng/L) for two types of PFASs, perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA).
Concentrations in some locations ranged as high as 349 ng/L for PFOA and 1,800 ng/L for PFOS.
The highest levels of PFASs were detected in watersheds near industrial sites, military bases, and wastewater treatment plants.
“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 both the Harvard Chan School and SEAS.
Other Harvard Chan authors of the study included Philippe Grandjean and Courtney Carignan. Funding for the study came from the Smith Family Foundation and a private donor.
The study was published August 9 in the journal “Environmental Science & Technology Letters.”
The authors say, “We have mapped watersheds in the United States that have potentially high concentrations of PFASs based on U.S. EPA data. This does not mean that all drinking water supplies within the highlighted regions contain high PFAS concentrations, but that at least one sample from at least one water supply was reported to be at or above levels considered safe by the U.S. EPA between 2013 and 2015.”
Saying that no measurements have been made in many water supplies across the country, the authors recommend “increased monitoring of these contaminants in our drinking water.”
The EPA has taken several recent actions to control PFASs:
- On January 21, 2015, EPA proposed a Significant New Use Rule under the Toxic Substances Control Act to require manufacturers (including importers) of PFOA and PFOA-related chemicals, including as part of articles, and processors of these chemicals to notify EPA at least 90 days before starting or resuming new uses of these chemicals in any products. This notification would allow EPA the opportunity to evaluate the new use and, if necessary, take action to prohibit or limit the activity.
- EPA’s New Chemicals program reviews alternatives for PFOA and related chemicals before they enter the marketplace to identify whether the range of toxicity, fate and bioaccumulation issues that have caused past concerns with perfluorinated substances may be present in order to ensure that the new chemicals may not present an unreasonable risk to health or the environment.
Another Harvard Chan School study, led by Grandjean, an adjunct professor of environmental health, published in “Environmental Health Perspectives,” also indicated negative health impacts of PFAS exposure.
That study looked at a group of about 600 adolescents from the Faroe Islands, an island country off the coast of Denmark. Those exposed to PFASs at a young age had lower-than-expected levels of antibodies against diphtheria and tetanus, diseases for which they had been immunized.
The findings suggested that PFASs, which are known to interfere with immune function, may be involved in reducing the effectiveness of vaccines in children.
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