PFAS: Neurological effects identified in birds and mice

As industry develops a new generation of PFAS to gradually replace older compounds that are now more tightly regulated, the effects of many of these emerging, unregulated PFAS remain largely unknown. To investigate some of their potential impacts, the researchers focused on a PFAS known as 7:3 FTCA, an increasingly widespread environmental contaminant produced by the degradation of fluorotelomer alcohols that are still used by industry.

The scientists combined two complementary approaches: one based on wildlife and the other using a laboratory model. Gull embryos—a sentinel species for coastal ecosystems—were exposed to concentrations of 7:3 FTCA comparable to those measured in the environment. The analyses revealed activation of the brain's immune cells in specific brain regions², with potential consequences for the cognitive development of these areas.

In parallel, laboratory mice received daily doses of the compound in their diet for three weeks, again at environmentally relevant exposure levels. The researchers found that activation of the brain's immune cells was accompanied by increased neuronal activity in the prefrontal cortex, as well as altered behaviour: the animals spent more time in illuminated areas and interacted for longer with their peers. These behavioural changes indicate reduced avoidance of situations perceived as risky.³

Published on 23 July in Environmental Science & Technology Letters, this study highlights previously undocumented neurological effects associated with this new generation of PFAS and underscores the need for further assessment of their potential impacts. The findings could also help evaluate the neurological effects of other PFAS compounds within a One Health approach integrating environmental, human and animal health.

Notes : 

¹ The two CNRS researchers are affiliated with the Centre d'Études Biologiques de Chizé (CNRS/La Rochelle Université) and the Centre de Résonance Magnétique des Systèmes Biologiques (CNRS/University of Bordeaux). The other co-authors are affiliated with the Basic Science Department, Loma Linda University School of Medicine (United States) and the Norwegian Polar Institute (Norway).

² In birds, the pollutant triggers targeted neuroinflammation: microglia—the brain's immune cells—become abnormally activated in the pallium.

³ These behavioural changes are directly associated with a 20% increase in neuronal activity in this brain region, without causing neuronal death.