Properties: PFAS Information for Clinicians - 2024

Properties of PFAS

Per- and polyfluoroalkyl substances (PFAS) are a family of thousands of synthetic chemicals that all contain a partially or fully fluorinated carbon chain. Their chemical properties allow them to reduce friction and resist oil and water. As a result, they have been widely used in industry and consumer products since the 1940s. Major applications include surfactants used in industrial processes and firefighting foams, and protectants for paper packaging products, carpets, and textiles that enhance water, grease, and soil repellency.

PFAS are widespread and persistent in the environment. The carbon-fluorine bonds are strong, so these compounds do not fully break down in the environment or human body. In humans, properties of the most well-studied PFAS include the following:

• Absorption: Absorbed in the intestines and lungs; limited dermal absorption
• Distribution: Bind to serum proteins; to a lesser extent, also bind to tissue proteins (e.g., liver, kidneys, and brain)
• Metabolism: Most not metabolized; some metabolized to other PFAS
• Elimination: Mainly in urine (clearance rate can vary by sex and kidney function); also, through defecation, menstruation, breastfeeding, and placental transfer
• Half-life: A few days to 8 years or more, depending on the specific PFAS