PFAS Mixtures More Toxic than Single Compounds, Suggesting Higher Danger

By: The Guardian

November 1, 2024

Recent research has shown that mixtures of PFAS in drinking water may be more toxic than individual PFAS compounds, raising significant health concerns. This study, led by researchers from the University at Buffalo and the Helmholtz Centre for Environmental Research in Germany, highlighted how combined exposures to multiple PFAS chemicals create heightened risks, affecting cellular function and potentially increasing health issues. Researchers found that exposure to multiple PFAS compounds together could increase neurotoxic and cytotoxic effects, particularly affecting cellular function, even though these combinations do not exhibit a synergistic effect (where combined toxicity is greater than the sum of individual toxicities). Instead, the study observed that the combined toxicity is additive, with certain PFAS compounds—like PFOA and PFOS—demonstrating higher toxicity levels. PFOA, for example, contributed to about 42% of the cytotoxicity in water mixtures and 70% in blood, underlining its particularly harmful nature.

Diana Aga, a co-author of the study, emphasized that PFAS should be regulated as mixtures to better reflect real-world exposure and mitigate health risks. Currently, people are often exposed to various PFAS compounds simultaneously, which may exacerbate the toxic effects. This research suggests that current safety thresholds might underestimate the true dangers posed by PFAS-contaminated water, especially in communities relying on groundwater sources frequently contaminated with these "forever chemicals." This insight adds to the mounting calls for more comprehensive regulatory frameworks that address the cumulative impact of PFAS exposure.

The study also examined PFAS mixtures found in sewage sludge, which is often used as fertilizer on farmland. This sludge, a byproduct of wastewater treatment, can contain numerous industrial and household chemicals, including various PFAS compounds. The presence of these chemicals in biosolids used in agriculture raises further concerns about PFAS exposure through food and water. Current regulations tend to assess PFAS chemicals individually rather than accounting for the cumulative effects of multiple PFAS, highlighting a regulatory gap. This research supports growing calls for regulatory bodies to evaluate PFAS contamination as a mixture to more accurately reflect real-world exposure risks.

For more details, see the original article and the published study.