Can Behavioral Responses to PFAS Exposure be Usedas a Sensitive Tool in Risk Assessment?

Per- and polyfluoroalkyl substances (PFAS) are a large group of synthetic chemicals found globally as contaminants in the environment, food, drinking water and in human bodies and wildlife. PFAS are bioaccumulating in the body, and high exposure to PFAS substances have been linked to health effects such as thyroid, liver, kidney and cardiovascular diseases and cancer. Both epidemiological studies and experiments on laboratory animals have also repeatedly linked low concentrations of PFAS to negative effects on the immune system and response to vaccination. This prompted the European Food Safety Authority, Efsa, in 2020 to establish a tolerable weekly intake of certain PFAS substances. EU has also significantly lowered levels allowed in drinking water to concentrations assumed to protect the public from adverse effects from exposure. This literature-based study examines effects of PFAS on the behavior of humans and animals, based on the hypothesis that behavioral alterations may occur as lower concentrations than the immunological effects that the regulatory measures are based on. Epidemiological evidence suggesting that children are at higher risk of exposure to elevated PFAS concentrations both prenatally and postnatally during critical periods of brain development. This study also aimed to investigate whether behavior and identification of the mechanisms behind behavioral alterations, can serve as sensitive indicators of low-concentration adverse neurotoxic effects, to aid in risk assessment. In conclusion, data on the effects of low-level PFAS exposure are limited, making it difficult to identify the concentration thresholds at which behavioral changes may occur. More studies are needed to assess the impacts of low-dose exposure to individual PFAS and mixtures, and to clarify the mechanisms by which they affect the developing and adult brain.