Researchers from the Keck School of Medicine at USC have made a groundbreaking discovery linking per- and polyfluoroalkyl substances (PFAS), commonly known as “forever chemicals,” in drinking water to an increased risk of certain cancers. The study, published in the Journal of Exposure Science and Environmental Epidemiology, is the first in the U.S. to directly examine how PFAS in drinking water correlates with higher cancer rates. Funded by the National Institutes of Health, the study indicates that communities exposed to PFAS contamination could face up to a 33% higher risk of cancers, including those affecting the digestive, endocrine, respiratory systems, and mouth and throat.
PFAS chemicals are synthetic compounds that are commonly used in consumer goods such as food packaging, furniture, and clothing. They have been detected in approximately 45% of drinking water supplies across the U.S. These chemicals are highly persistent in the environment and accumulate in the human body over time. Previous studies have already linked PFAS exposure to several health conditions, including kidney, breast, and testicular cancers. However, this new research provides strong evidence of a direct connection between PFAS exposure through drinking water and various forms of cancer.
Study Methodology and Findings
In their study, the Keck School of Medicine researchers used large population-level datasets to identify patterns of PFAS exposure and associated cancer risks. Between 2016 and 2021, counties with PFAS-contaminated drinking water exhibited higher rates of specific cancers, with increases in incidence ranging from a modest 2% to a substantial 33%, particularly in cases of mouth and throat cancers linked to PFBS, a type of PFAS.
The study found that males living in areas with contaminated drinking water had a higher incidence of leukemia, brain cancer, and cancers of the urinary system and soft tissues. Meanwhile, females in these areas exhibited a higher incidence of cancers in the thyroid, mouth and throat, and soft tissues. Overall, the researchers estimate that PFAS contamination in drinking water contributes to approximately 6,864 cancer cases annually across the U.S.
“These findings are significant as they provide concrete evidence of the cancer burden attributed to PFAS exposure,” said Dr. Shiwen (Sherlock) Li, the lead author of the study. “By quantifying the number of cancer cases tied to PFAS, we gain a clearer understanding of the personal and financial toll these chemicals take on affected communities.”
Regulatory Implications
The findings have significant implications for public health policy and the regulation of PFAS in drinking water. The U.S. Environmental Protection Agency (EPA) is set to regulate six types of PFAS starting in 2029, but the study’s authors caution that stricter limits may be needed to fully protect public health.
“Certain PFAS chemicals that are less studied or not yet regulated need more scrutiny, and regulators should consider additional PFAS chemicals that may pose similar risks,” Dr. Li added. This research underscores the need for more comprehensive monitoring and regulation of these harmful substances to prevent further harm.
Next Steps in Research
While the study highlights the strong association between PFAS and cancer, further research is needed to understand the specific biological mechanisms behind this link. The next step for researchers is to conduct individual-level studies to explore whether the correlation is causal and to delve deeper into the biological processes that could explain the increased cancer risk.
Additionally, the findings provide a roadmap for future studies on PFAS and health risks, urging researchers to examine specific cancers more closely and to investigate whether other rare cancer types may also be linked to PFAS exposure. This research is essential for developing more targeted approaches to prevent and mitigate the harmful effects of these ubiquitous chemicals.
