Toxicology, risk assessment, and risk management of PFAS: state of the science

Many scientific and regulatory data gaps are currently associated with the assessment and management of per and polyfluoroalkyl substances (PFAS) in the environment. PFAS associated with aqueous film-forming foam (AFFF), used in the fighting of Class B hydrocarbon fires, as well as other industrial and consumer uses, can include hundreds to thousands of compounds with varying mobility and toxicity. These mixtures routinely exceed risk-based screening thresholds at their point of release, and also have the potential to impact downgradient aquatic resources such as aquifer and aquatic ecosystems. Understanding the key ecological and human health exposure pathways and receptors at risk from exposure to PFAS will help prioritize site-specific assessments and potential mitigation of risks. (author)