Communities of color disproportionately exposed to PFAS pollution in drinking water
Boston, MA – People who live in communities with higher proportions 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 living in other communities, according to a new study led by researchers from Harvard T.H. Chan School of Public Health. The researchers link this finding to the disproportionate siting of sources of PFAS pollution—such as major manufacturers, airports, military bases, wastewater treatment plants, and landfills—near watersheds serving these communities.
The study will be published online May 15, 2023, in Environmental Science & Technology.
In March, the EPA proposed the first-ever national drinking water regulation for six PFAS, which it anticipates finalizing by the end of 2023. The regulation would establish maximum contaminant levels of two PFAS compounds, PFOA and PFOS, at 4 parts per trillion (4 ng/L) and limit the other four. The public comment period ends 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,” said first author Jahred Liddie, a PhD student in population health sciences at Harvard Chan School. “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.”
This is the first peer-reviewed study to show sociodemographic disparities in drinking water PFAS exposures and to statistically link sources such as landfills and airports to PFAS concentrations in community water systems over broad geographic scales.
PFAS—dubbed “forever chemicals” because of their extreme persistence in the environment due to their characteristic fluorine-carbon backbone—are artificial compounds widely used for their stain-resistant and water-resistant properties. PFAS exposure has been associated with numerous adverse health outcomes, including diabetes, cardiovascular disease, and cancer.
The researchers used PFAS monitoring data from 7,873 U.S. community water systems in the 18 states in which such data is widespread: California, Colorado, Illinois, Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, South Carolina, Utah, Vermont, and Wisconsin. Their analysis included 44,111 samples collected between January 2016 and August 2022. They also looked at the geographic locations of PFAS sources from multiple databases.
The study found that PFAS detection was positively associated with the number of PFAS sources and proportions of people of color who are served by a water system. Each additional industrial facility, military fire training area, and airport in a community water system’s watershed was associated with a 10%−108% increase in perfluorooctanoic acid and a 20%−34% increase in perfluorooctane sulfonic acid in drinking water.
According to the researchers, about 25% of the population in the 18 states considered in their study were served by community water systems that had levels of PFAS above 5 ng/L. Per this estimate, if the EPA’s new proposed level of 4 ng/L is implemented, more than 25% of all Americans are likely to be considered 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,” said senior author Elsie Sunderland, Fred Kavli Professor of Environmental Chemistry and 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. “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.”
Laurel Schaider at Silent Spring Institute was a co-author.
This research was supported by the National Institute of Environmental Health Sciences (NIEHS) grant P42ES027706, grant R01ES028311, and an NIEHS training grant (T32 E007069).
“Sociodemographic Factors Are Associated with the Abundance of PFAS Sources and Detection in U.S. Community Water Systems,” Jahred M. Liddie, Laurel A. Schaider, Elsie M. Sunderland, Environmental Science & Technology, online May 15, 2023, doi: 10.1021/acs.est.2c07255
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JOURNAL
Environmental Science & Technology
METHOD OF RESEARCH
Observational study
SUBJECT OF RESEARCH
Not applicable
ARTICLE TITLE
Sociodemographic Factors Are Associated with the Abundance of PFAS Sources and Detection in U.S. Community Water Systems
ARTICLE PUBLICATION DATE
15-May-2023
EPA's new PFAS rules don’t account for major source of drinking water contamination
Harvard study reveals unmonitored PFAS build up and last for centuries
Peer-Reviewed PublicationIMAGE: MEMBERS OF THE SUNDERLAND LAB SAMPLING FOR PFAS CONTAMINATION ON CAPE COD view more
CREDIT: MICHAEL SALERNO
CAPE COD, MASSACHUSETTS – Earlier this year, the US Environmental Protection Agency proposed maximum allowable levels in drinking water for six PFAS (per- and polyfluoroalkyl substances) – so-called forever chemicals. But the draft standards do not account for half of the PFAS at contaminated sites across the country.
The findings are from a team led by the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and are published in the journal Environmental Science & Technology.
PFAS are present in fire retardant foams among other products and have been building up in the environment since they were first invented by Dupont in the 1930s and manufactured widely by 3M beginning in the 1950s. Exposures to some PFAS are linked to a range of health risks including cancer, immune suppression, diabetes, and low infant birth weight.
PFAS compounds come in two forms: a precursor form and a terminal form. Most of the monitored PFAS compounds are terminal compounds. The EPA’s draft drinking water rules are for six terminal compounds that do not degrade under normal environmental conditions. Precursor compounds can be transformed through biological or environmental processes into terminal forms. There are many precursor compounds, most of which are not routinely monitored, and none are currently regulated.
The U.S. military is the largest global user of fire-retardant foams containing PFAS known as AFFF (aqueous film forming foam). For decades, hundreds of military bases across the U.S. and around the world used AFFF containing high levels of PFAS for fire training drills and fighting fires. AFFF use is one of the largest sources of PFAS contamination in drinking water.
“Many PFAS precursors present in AFFF are difficult to measure. This work shows that they are slowly transforming into PFAS of health concern at AFFF-contaminated sites and contributing to downstream contamination” said Elsie Sunderland, Fred Kavli Professor of Environmental Chemistry and Professor of Earth and Planetary Sciences at SEAS and senior author on the new paper.
Much of the PFAS at military sites consists of precursors that are omitted from standard analytical methods. Using a method previously developed in the Sunderland lab that captures all precursors in AFFF, the Harvard team modeled the expected duration and contribution of those precursors to groundwater contamination. The study finds that contamination of two of the newly regulated PFAS chemicals (perfluorohexane sulfonate: PFHxS and perfluorbutane sulfonate: PFBS) at one military base on Cape Cod, Massachusetts are sustained by microbial precursor biotransformation in the soil. These precursors are retained in the soil where they leach into groundwater in terminal form at concentrations thousands of times greater than the safe levels established by the EPA.
The researchers projected using a computer model and field data that, without remediation, widespread PFAS contamination of drinking water supplies near military facilities is likely to persist for centuries. Despite contamination of nearby aquifers that may already pose a risk to human health, the majority of PFAS are still sitting in the soils surrounding these contaminated sites, emphasizing the urgent need for advances in remediation technology that are effective at cleaning up both terminal and precursor compounds. Since regulations focus only on terminal compounds, the effectiveness of current remediation technologies at cleaning up precursors is not known.
The researchers concluded that elevated PFAS exposures downstream of more than 300 U.S. military facilities that used the fire-fighting foams could similarly persist for centuries.
“The role of PFAS precursors in sustaining hazardous levels of contamination at Joint Base Cape Cod raises concern about whether exposure risks are underestimated near hundreds of other sites where they are not measured” said Bridger Ruyle, the first author of the study and former doctoral student in Sunderland’s Lab.
The public comment period for EPA’s draft PFAS drinking water regulation closes on May 30. While a step in the right direction, there are thousands of PFAS chemical structures, several hundred of which have already been detected in the environment, Sunderland notes.
In related work also published in Environmental Science & Technology today, Sunderland’s group also has shown that the number of military fire training areas within a watershed is a good predictor for PFAS contamination in a community’s drinking water supply. But some groups are at higher risk than others; a forthcoming publication by the Sunderland lab documents marked sociodemographic disparities in exposures to PFAS and proximity to PFAS sources across the country.
Additional authors include Colin Thackray and Chad Vecitis of Harvard; Craig Butt of AB Sciex LLC; and Denis LeBlanc and Andrea Tokranov of the U.S. Geological Survey.
Funding for the research was provided by the Department of Defense Strategic Environmental Research and Development Program (SERDP ER18-1280) and the U.S. National Institute for Environmental Health Sciences Superfund Research Program (P4ES027706). Additional support was provided by the U.S. Geological Survey Toxic Substances Hydrology Program.
JOURNAL
Environmental Science & Technology
METHOD OF RESEARCH
Observational study
ARTICLE TITLE
Centurial Persistence of Forever Chemicals at Military Fire Training 2 Sites
ARTICLE PUBLICATION DATE
15-May-2023
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