March 20, 2023 – A new study suggests that recent government efforts to limit human exposure to hormone-disrupting “forever chemicals” may miss the mark and not provide much protection.
That's because researchers found that it's the mixture of substances that becomes toxic in humans, and current efforts aim to regulate the substances on a chemical-by-chemical basis. The study offered further cause for concern because it increased children's exposure to the substances and found levels that are toxic to development.
Called per- and polyfluoroalkyl substances, the synthetic chemicals are known as PFAS and are widely used in consumer and industrial products. PFAS break down slowly and can accumulate in the environment and in human tissue.
“Our findings were surprising and have broad implications for policy makers trying to mitigate risk,” said lead author Jesse A. Goodrich, PhD, assistant professor at the University of Southern California's Keck School of Medicine, in a statement. “We found that exposure to a combination of PFAS not only disrupted lipid and amino acid metabolism but also altered thyroid hormone function.”
The authors explained that theirs was the first study to look at the effects of PFAS as a mixture (which is more realistic of typical exposure), whereas previous studies examined the effect of a single PFAS in isolation. The Environmental Protection Agency recently announced regulation of six PFAS in drinking water. There are thousands of different PFAS, the EPA says.
The study was published last month in the journal Environmental Health Perspectives. Researchers analyzed blood samples from two groups of children and adolescents. All of the 449 young people had a mixture of commons PFAS in their blood that altered metabolism and thyroid function in ways known to impact development and also known to contribute to the risk of adult diseases, such as diabetes, cardiovascular problems, and cancer.
The authors noted that due to the age range of the children in the study, they were able to conclude that efforts in the early 2000s to regulate some PFAS did not meaningfully protect people from exposure.
“This trend may suggest that the toxicological effects of PFAS exposure are more related to total PFAS levels, rather than individual PFAS compounds,” they wrote. "Our findings lend support to the argument that PFAS should be regulated as a chemical class rather than being regulated on a chemical-by-chemical basis.”