What are the human and ecological exposure pathways and health effects?
Human and ecological exposures to PFASs can include any of the basic exposure pathways for chemicals in the environment. Exposure pathways that originate with PFASs in water, sediment, soil, dust, and gas (e.g., atmosphere, soil vapor) can including direct absorption across the skin or dermis, inhalation of volatile PFASs or PFASs bound to particulates, and direct ingestion.106,107 Because PFASs can accumulate in biological tissue and lead to biomagnification of PFASs within food webs,108 consumption of animals and plants can also be an important exposure pathway.4,109
In terms of investigating sites contaminated with PFASs, risks associated with the following key exposure routes are usually the focus of most quantitative evaluations of human exposures:
Direct ingestion of drinking water that is contaminated due to PFASs present in surface water or groundwater resources. This can be an important exposure pathway for both on-site and off-site receptors, as many PFASs are water soluble and can impact water resources several miles from the point of initial release.
Incidental dietary ingestion of soil, dust, or sediment due to interaction with these media.
Ingestion of food contaminated with PFASs. This can occur due to the accumulation of PFASs in plants (produce) grown on PFAS-contaminated soilor irrigated with PFAS-contaminated water. Some PFASs can also bioaccumulate in aquatic food webs and reach concentrations of concern in aquatic animals such as fish or mussels that are consumed byhumans.
Because of their environmental mobility, this process can occur in aquatic ecosystems both on- and off-site.