PFAS Exposure

First-of-its-kind research highlights need for change to regulation, as humans almost always exposed to mixtures.

PFAS are a class of about 15,000 compounds most frequently used to make products water, stain and grease-resistant. They have been linked to cancer, birth defects, decreased immunity, high cholesterol, kidney disease and a range of other serious health problems. They are dubbed “forever chemicals” because they do not naturally break down in the environment.

Humans are almost always exposed to more than one PFAS compound at a time, but regulatory agencies largely look at the chemicals in isolation from one another, meaning regulators are probably underestimating the health threat.

Mixtures of different types of PFAS compounds are often more toxic than single chemicals, first-of-its-kind research finds, suggesting humans’ exposure to the chemicals is more dangerous than previously thought.

Recent studies, which relied on modeling with in vitro cells, not human or animal studies, checked the neurotoxicity and cytotoxicity for combinations of up to 12 PFAS compounds that the federal government has regularly found in water.

It also looked at a combination of four PFAS that the US Centers for Disease Control and Prevention has often found in blood serum. Cytotoxicity refers to toxicity to cells, and the researchers measured oxidative stress, which is a marker of potential health impacts.

The research did not find a synergistic effect in which a combination of PFAS enhanced the chemicals’ toxicity – instead, it showed that the toxicity is additive.

The sum of those chemicals can present a danger, even if they are below the Environmental Protection Agency’s drinking-water limits of 4ppt (parts per trillion) for each.

Hypothetically, if PFOA and PFOS levels were present at 3ppt each, then the water would be considered safe by EPA standards. But the sum of each chemical’s toxicity would probably make the water dangerously toxic.

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