A new study highlights the increased toxicity of certain PFAS, commonly known as “forever chemicals,” when mixed together. The findings could impact environmental regulations and treatment methods for these persistent contaminants.
A landmark study by researchers at the University at Buffalo, in collaboration with Helmholtz Centre for Environmental Research in Leipzig, Germany, has revealed a crucial finding about per- and polyfluoroalkyl substances (PFAS), commonly referred to as “forever chemicals.” The study meticulously measured the toxicity levels of various PFAS when combined, disclosing that their collective toxicity significantly intensifies, even though individually, their toxicity appeared minimal.
The research team, led by University at Buffalo doctoral student Karla Ríos-Bonilla and Diana Aga, the director of the UB RENEW Institute and SUNY Distinguished Professor and Henry M. Woodburn Chair in the UB Department of Chemistry, performed high-throughput screening to assess the compounds.
The study was published in Environmental Science & Technology, a journal of the American Chemical Society.
Why It Matters
PFAS are synthetic compounds that have been integrated into numerous consumer products, such as nonstick cookware and cosmetics, for decades.
These chemicals are notoriously long-lasting in the environment, often remaining for hundreds or thousands of years, and have been detected in 45% of the nation’s drinking water and the blood of almost every American.
This study stands out as it evaluates the mixture toxicity of these ever-present chemicals. Such mixtures are often found in both human blood and the environment. With these chemicals being linked to serious health problems, including cancer and neurodevelopmental disorders, understanding their behavior in mixtures is critical.
Ríos-Bonilla emphasized the nuanced toxicity of PFAS mixtures.
“Though they are structurally similar, not all forever chemicals are made equal — some are more potent, others less. When mixed, all components contributed to the mixture’s cytotoxicity and neurotoxicity,” she said in a news release.
Aga added to this perspective.
“In the laboratory assays we used in this study, most of the types of PFAS that we tested did not appear to be very toxic when measured individually. However, when you measure an entire sample with multiple PFAS, you see the toxicity,” she said in the news release
Significance of the Findings
The implications of these findings are substantial, especially considering that the U.S. Environmental Protection Agency (EPA) only recently issued drinking water standards for six types of PFAS, despite over 15,000 varieties being present in the environment. Only a few of these chemicals are currently regulated.
As Aga highlights, understanding the relative potencies of these chemicals in mixtures is essential for setting effective contamination standards and protecting public health.
On conducting the research, Ríos-Bonilla and her team crafted PFAS mixtures representative of the average American’s blood serum and U.S. surface water samples, testing their effects on cell lines for mitochondrial toxicity, oxidative stress and neurotoxicity.
They found that perfluorooctanoic acid (PFOA) was the predominant contributor to the mixtures’ cytotoxicity, while both PFOA and perfluorooctane sulfonic acid (PFOS) significantly contributed to neurotoxicity.
An intriguing finding from an analysis of real biosolid samples from a municipal wastewater treatment plant showed high toxicity levels despite low concentrations of known PFAS like PFOA.
“This means that there are many more PFAS and other chemicals in the biosolids, which have not been identified, that contribute to the toxicity of the extracts observed,” Aga added.
Looking Forward
The results underline the pressing need for more comprehensive regulation and research on PFAS mixtures.
“Mixtures pose more of a risk than individual PFAS. As they act and occur in mixtures, they ought to be regulated as mixtures,” added Beate Escher from the Helmholtz Centre.
This study also holds promise for better remediation efforts.
“Toxicity assays can be a complementary tool when analytical chemistry doesn’t give you all the answers, especially when the identities of contaminants in the mixture are unknown, which is the case in many polluted sites,” said Aga.
As PFAS continue to be a pervasive environmental and health challenge, this study provides valuable insights that could shape future policies and treatment strategies, making a significant impact on public health and safety.