Higher PFAS Levels in Blood Linked to Neighborhood Factors

In a new study, researchers at University of Southern California (USC) have associated certain neighborhood factors — such as food access or proximity to Superfund sites — with higher levels of per- and polyfluoroalkyl substances (PFAS) in human blood.

The researchers examined the levels of certain types of PFAS, including PFOS, PFOA, PFHxS, PFPeS and PFHpS based on a neighborhood’s tap water, level of access to fresh foods and proximity to industrial polluting sites and Superfund sites. As explained by the U.S. Environmental Protection Agency, a Superfund site is an area designated as a hazardous waste dumping ground, such as landfills, mining sites and some types of manufacturing facilities.

The study drew from two previous Southern California-based studies’ data to observe how the defined neighborhood factors affected the PFAS levels in the blood of 446 people, mostly based in Los Angeles County, LAist reported.

The results revealed that each factor on its own was associated with elevated levels of certain types of PFAS in the blood. The team published the results in the journal Environmental Research.

“Instead of placing the burden on individuals to avoid PFAS, we’re looking at neighborhood factors beyond their control,” Shiwen (Sherlock) Li, Ph.D., lead author of the study and postdoctoral researcher at USC’s Keck School of Medicine, said in a statement. “How can we improve our neighborhood environments to reduce PFAS and the associated disease risk?”

The results revealed that places with PFOA, PFOA or PFHxS in the tap water also had residents with higher levels of these compounds in their blood compared to people without these compounds detected in the tap water. The areas with PFAS in the water revealed an increase of around 1.54 nanograms per milliliter (ng/mL) of PFOS, 0.47 ng/mL for PFOA and 116 ng/ML for PFHxS.

The study also reviewed low access to fresh food as a potential link to higher PFAS in blood, because PFAS have been found in food packaging. This neighborhood factor was linked to higher levels of PFOS (an increase of 2.52 ng/mL), PFOA (0.6 ng/mL increase) and PFHpS (0.06 ng/mL) in human blood, with increases by around 40% to 60% and even over 100% for certain PFAS, as LAist reported.

The results found elevated levels of PFOS for people living within a 3-mile radius of an industrial site known for processing PFAS, and it showed higher levels of PFOS, PFHxS, PFHpS and PFPeS for people living within 3 miles of a Superfund site. In August 2024, a separate study revealed that landfills have become major sources of airborne PFAS pollution, although exact measurements of the amounts of PFAS pollution from landfills are still uncertain.

As the Keck School of Medicine reported, the residents in the study were primarily Latino, which highlighted the need for environmental justice efforts to address PFAS in underserved communities.

“We’re adding a different perspective to solving the PFAS problem, because the risk to exposure of PFAS at the neighborhood level is not evenly distributed,” Li said.

Currently, the Keck School of Medicine’s Department of Population and Public Health Sciences has ramped up efforts to educate communities about PFAS contamination in water, although Li emphasized the importance of systemic changes to reduce PFAS pollution.

“In my opinion, it’s harder to change individual behaviors, but if you can create clean environments for everyone, they don’t need any behavioral change in the first place,” Li explained, as reported by LAist.

The EPA is making efforts to regulate PFAS, two of which (PFOA and PFOS) were added to the list of hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA).

In April 2024, EPA finalized regulations for six types of PFAS in drinking water, and these rules are set to take effect in 2029.