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Sociodemographic Disparities in Drinking Water PFAS Exposures

According to recent research conducted by Harvard T.H. Chan School of Public Health researchers, people who live in communities with a higher proportion of Black and Hispanic/Latino residents are more likely to be exposed to harmful levels of per- and polyfluoroalkyl substances (PFAS) in their water supplies than people who live in other communities.

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The researchers attribute this finding to the disproportionate placement of PFAS pollution sources near watersheds supplying these communities, such as major manufacturers, airports, military facilities, wastewater treatment plants, and landfills.

The research was published in the Environmental Science & Technology journal.

The EPA proposed the first-ever nationwide drinking water regulation for six PFAS in March, which it hopes to finalize by the end of 2023. The regulation would set maximum contaminant levels for two PFAS compounds, PFOA and PFOS, at 4 parts per trillion (4 ng/L), while restricting the remaining four. The public feedback period is set to finish on May 30.

Our work suggests that the sociodemographic groups that are often stressed by other factors, including marginalization, racism, and poverty, are also more highly exposed to PFAS in drinking water. Environmental justice is a major emphasis of the current administration and this work shows it should be considered in the upcoming regulations for PFAS in drinking water.

Jahred Liddie, Study First Author and Ph.D. Student, Population Health Sciences, Harvard T.H. Chan School of Public Health

This is the first peer-reviewed research showing sociodemographic differences in PFAS exposures in drinking water and to statistically link sources like landfills and airports to PFAS concentrations in community water systems across broad geographic scales.

PFAS, sometimes known as “forever chemicals” due to their extraordinary persistence in the environment due to their unique fluorine-carbon backbone, are synthetic compounds widely utilized for their stain- and water-resistant qualities.

PFAS exposure has been linked to a variety of negative health effects, including diabetes, cardiovascular disease, and cancer.

The researchers analyzed PFAS monitoring data from 7,873 community water systems in California, Illinois, Indiana, Colorado, Kentucky, Maine, Massachusetts, Maryland, Michigan, New Jersey, New Hampshire, New York, Pennsylvania, South Carolina, Ohio, Utah, Vermont, and Wisconsin, which have a high prevalence of such data.

They looked at 44,111 samples obtained between January 2016 and August 2022. They also examined the geographical locations of PFAS sources using several databases.

The study discovered that PFAS detection was related to the number of PFAS sources and the proportion of people of color served by a water system. Each additional industrial facility, military fire training area, and airport in the watershed of a community water system was related to a 10 – 108% rise in perfluorooctanoic acid and a 20–34% increase in perfluorooctane sulfonic acid in drinking water.

According to the scientists, community water systems with PFAS levels exceeding 5 ng/L fed approximately 25% of the population in the 18 states studied. According to this estimate, if the EPA’s new suggested level of 4 ng/L is enforced, more than 25% of all Americans will be exposed to dangerous levels of PFAS.

Our findings are particularly concerning because past work on environmental disparities for other pollutants shows marginalized populations are susceptible to greater risks of adverse health outcomes compared to other populations, even at the same exposure levels. Regulating releases from PFAS sources and ensuring that people have safe drinking water is especially important in the most vulnerable communities to protect public health.

Elsie Sunderland, Study Senior Author and Fred Kavli Professor, Environmental Chemistry, Harvard T.H. Chan School of Public Health

Elsie Sunderland is also the Professor of Earth and Planetary Sciences at the Harvard John A. Paulson School of Engineering and Applied Sciences and Professor of Environmental Science and Engineering in the Department of Environmental Health at Harvard Chan School.

Laurel Schaider at Silent Spring Institute was a co-author.

The study was supported by the National Institute of Environmental Health Sciences (NIEHS) grant P42ES027706, grant R01ES028311, and a NIEHS training grant (T32 E007069).

Journal Reference:

Liddie, J. M., et al. (2023) Sociodemographic Factors Are Associated with the Abundance of PFAS Sources and Detection in U.S. Community Water Systems. Environmental Science & Technology.

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