Researchers Warn Toxic PFAS Pollutants Can Penetrate Blood-Brain Barrier

Amid on-going concerns about the potential health risks associated with per- and polyfluoroalkyl substances (PFAS), which have widely polluted water sources throughout the U.S. and been linked to an increased risk of cancer and other ailments, the findings of a new study suggest that the chemicals can accumulate in the brain, leading to a number of potential long-term health risks.

PFAS include a group of over 9,000 man-made substances, which are widely used to resist grease, oil and water. However, they are known to persist for decades, and researchers have identified a myriad of adverse health effects linked to the chemicals, including testicular cancer, kidney cancer, ulcerative colitis and other side effects.

Most of the PFAS health concerns have stemmed from water contamination problems, caused by the large volumes of the chemicals in aqueous film-forming foam (AFFF), which have been used by the military and firefighters for decades to fight fuel-based fires. During training and response exercises, these PFAS chemicals have been dumped into the environment and local water supplies, particularly around military bases, airports and firefighter training locations, causing many communities to have dangerous levels of the chemicals in their drinking water.

3M Company, DuPont, Chemguard, Inc., Tyco Fire Products and other manufacturers of chemicals and fire safety products now face thousands of PFAS water contamination lawsuits brought by local water providers and individuals diagnosed with various types of cancer. The companies also face hundreds of firefighter cancer lawsuits over exposure to AFFF, and evidence uncovered during litigation has further heightened concerns about the long-term risks associated with use of the chemicals.

In this latest study, Chinese researchers looked at nearly two dozen plasma samples from glioma patients and analyzed them for 17 known PFAS, including both older chemicals and more recent formulations. They then looked at concentrations of PFAS in brain tissues in those patients. Their findings were published on May 6 in the journal Environmental International.

“The results indicated that low molecular weight PFAS, including short-chain and emerging PFAS, may have a greater potential for accumulation in brain tissue than long-chain PFAS,” the researchers reported.

The data indicates that accumulation of some PFAS in the brain was correlated between levels found in plasma samples, suggesting that the chemicals can accumulate in the brain through the bloodstream, particularly perfluorooctane sulfonic acid (PFOS).

“Per- and polyfluoroalkyl substances are found to pose toxic risks to various human organs, including but not limited to thyroid, liver, kidney, and brain,” the researchers determined. “Notably, brain, being a vital and highly protected organ, is particularly vulnerable to these exogenous substances. Despite the presence of the blood–brain barrier (BBB), PFAS can penetrate the BBB and accumulate in both infant and adult brains.”

They also found that age could be a factor, with the brain letting more chemicals through the BBB as individuals get older. However, the researchers also noted that, due to the difficulty in obtaining and comparing brain tissue samples, the study is only a preliminary pilot investigation.

“It should be recognized that the conclusions drawn from the present study should be considered preliminary due to the difficulty in obtaining a large number of paired brain tissue and plasma samples,” the researchers noted. “Future studies based on more paired samples and influencing factors are needed to better characterize human brain exposure to environmental chemicals.”

May  2024 PFAS Lawsuit Update

Given common questions of fact and law presented in thousands of lawsuits against AFFF and PFAS manufacturers over the cancer risks linked to use of the chemicals in firefighting foam, coordinated pretrial proceedings have been established in the federal court system before U.S. District Judge Richard M. Gergel in the District of South Carolina, where the claims are currently centralized for discovery and a series of early bellwether trials.

Although the manufacturers have reached proposed settlement over damages sustained by local water suppliers, who have been left with the costs associated with cleaning up the toxic chemicals, there have been no settlements in PFAS injury lawsuits brought by individuals exposed to the chemicals through drinking water, or firefighters directly exposed through AFFF foam.

Last year, Judge Gergel directed the lawyers involved in the litigation to select a group of 28 representative personal injury claims for an PFAS injury bellwether pool, involving plaintiffs who say they were exposed to chemicals that contaminated drinking water.

However, the first cases are unlikely to go before a jury for several years. In addition, the outcome of these claims will not have any binding impact on the other individual lawsuits, although they will be closely watched and may influence how much manufacturers may pay to settle lawsuits brought by other plaintiffs.