PFAS are a class of synthetic fluorinated chemicals used in many industrial and consumer products, including defense-related applications. They are persistent and can be found at low levels in the environment, and bio-accumulate.

The sources that can release significant quantities of PFAS into the environment could be industrial and municipal wastewater treatment plants (e.g. from textile industry, chrome-plating industry), landfill leachate treatment plants, fire-fighting incidents and fire-fighting training areas (e.g., at airports, fuel production and storage facilities) and landfills.

Human exposure to PFAS is primarily by ingestion of contaminated foods or water. These compounds are not metabolized, bind to proteins (not to fats) and are mainly detected in blood, liver and kidneys. Elimination of PFOS, PFHxS and PFOA from the human body takes years, whereas elimination of shorter chain PFAS is in the range of days. As a result the EPA is primarily focused on the long chain PFAS compounds. Concern around the environmental effects of PFAS use began in the late 1990s when it was realized (due to their resistance to biodegradation) PFOS and PFOA were ubiquitous in various biological (wildlife and humans) and environmental (water bodies) matrices.

Solid phase extraction and liquid chromatography / tandem mass spectrometry (LC/MS/MS) is used to determine the majority of PFAS compounds although specific precautions are required in sampling of environmental media since PFAS adsorb strongly to glass. Teflon-containing materials can also lead to an increased background level. Currently the most appropriate material for sampling seems to be using polyethylene or polypropylene.