Understanding PFAS Exposure and Your Body

Per- and polyfluoroalkyl substances (PFAS) can be measured in the blood. Your PFAS blood levels will tell you the amount of PFAS in your body and are determined by how much PFAS you have been exposed to (exposure), minus how much PFAS have left your body (excretion).

Exposure and excretion are different for each person. For example, two members of the same household may have very different PFAS levels in their bodies.

Exposure happens when a person breathes, eats, drinks, or touches a chemical and it enters their body.

How are people exposed to PFAS?

  • People living near sites where a release of PFAS has occurred may be exposed through air, soil, or drinking water contaminated by PFAS.
  • People may be exposed to PFAS from some consumer products (food packaging, stain resistant carpeting and upholstery, water repellent clothing, etc.).
  • People may be exposed by eating food grown or raised in PFAS contaminated soil or water, including agricultural products, wild game, and fish.
  • Babies born to mothers who were exposed to PFAS can be exposed before they are born, while breastfeeding, or while drinking formula mixed with PFAS contaminated water.
  • For most PFAS, showering and bathing in water containing PFAS should not significantly increase exposure.
  • People who work around or with PFAS (e.g., manufacturing chemicals or using fire-fighting foam) may breathe in PFAS.

Excretion is the process whereby substances, like PFAS, leave the body.

How are PFAS excreted from the body?

  • Some PFAS leave the body slowly over time, mostly through urine. People who have kidney disease may not excrete as much PFAS from their body through their urine as healthy individuals.
  • Some PFAS routinely leave the body in blood during menstruation. Those who menstruate may excrete more PFAS than those who do not.
  • Some PFAS can leave the body in breastmilk. Those who breastfeed may excrete more PFAS from their bodies than those who do not.
  • All of these factors could affect PFAS levels measured in your blood. At this time, we are unable to use PFAS blood levels to decide what harmful effects might be possible.
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Page last reviewed: September 9, 2022