Luca Facchinello (Collegio Carlo Alberto)

PFAS Exposure and Cognitive Development: Evidence from a Geographic Quasi-Experiment

Abstract. PFAS, highly persist chemicals widely used in manufacturing, are found in the blood of people and animals all over the world. While many studies associate PFAS exposure to adverse health and developmental effects in humans, there is currently no causal evidence on this association. This paper considers a well-known Italian PFAS contamination incident to provide first-hand causal evidence on the relationship between water-borne PFAS exposure and cognitive development. Improper disposal of industrial waste by a PFAS producer located in the Veneto Region led to decades-long severe contamination of the water supply for about thirty contiguous municipalities. Potential exposure stopped in 2013, shortly after the incident was discovered. Following Keele et al (2017) I exploit the setup as a geographic quasi-experiment (GQE). I compare children studying in contaminated and non-contaminated schools (proxying for residence) close to the border of the polluted area, before pollution discovery, to identify total effects of PFAS pollution on academic performance, measured by grades and test scores. I find small and robust negative effects, around -10% of a standard deviation, masking substantial heterogeneity: effects range from -1.5% to -38% of a standard deviation depending on PFAS contamination levels. Further heterogeneity analysis sheds light on both mechanisms and limitations in the analysis.