Biomonitoring - Perfluorochemicals (PFAS)

Perfluorochemicals, more commonly known as per- and polyfluoroalkyl substances (PFAS), are a group of synthetic chemicals that have been used in many consumer products. This indicator presents data for four PFAS commonly detected in people: perfluorooctanoic sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA).

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Indicator
About the PFCs Indicator
Data Sources and Methods
Related Links

Indicator

B7: PFAS in women

Web update: 2025

Key Information

Exposures to four PFAS commonly detected in people has declined in the past 25 years. For example, between 1999-2000 and 2017-2020 the median level of PFOS in the blood of women of child-bearing age declined from 24 ng/mL to 2.3 ng/mL. The median represents the midpoint of exposure.
The 95th percentile level of PFOS in the blood of women declined from 50 ng/mL to 8.0 ng/mL. The 95th percentile represents higher exposure.
In 2015–2020, women of child-bearing age living at or above poverty level had higher median levels of PFOA, PFOS, and PFNA in their blood compared with women living below poverty level.

Data Characterization

Data for this indicator are obtained from an ongoing continuous survey conducted by the National Center for Health Statistics.

Survey data are representative of the U.S. civilian noninstitutionalized population.

PFAS are measured in blood samples obtained from individual survey participants.

About the PFAS Indicator

Perfluorochemicals, more commonly known as per- and polyfluoroalkyl substances (PFAS), are a group of widely used, long lasting chemicals, components of which break down very slowly over time. There are thousands of PFAS found in many different products. Historically, the PFAS with the highest production volumes in the United States were perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). These chemicals are no longer used in the United States but continue to persist in the environment and in people for many years, despite reductions in emissions. The major sources of children’s exposure to PFAS include food, water, indoor and outdoor air, breast milk, and dust. Some PFAS have been widely detected in pregnant women and in umbilical cord blood, suggesting that developing babies can be exposed to PFAS while in the womb.

EPA’s recent assessments of PFOS and PFOA identified effects on the immune system, cardiovascular system, childhood development, and the liver, even at low levels of exposure. EPA has committed to take action to combat PFAS contamination.

For historic and contextual information about PFAS and these indicators, see the PFC section of America's Children and the Environment, Third Edition (pdf) (688.54 KB) .

Data Sources and Methods - PFAS

The National Center for Health Statistics, a division of the Centers for Disease Control and Prevention, conducts the National Health and Nutrition Examination Surveys (NHANES), a series of U.S. national surveys of the health and nutrition status of the noninstitutionalized civilian population. Interviews and physical examinations are conducted with approximately 10,000 people in each two-year survey cycle. The survey measures PFAS levels in blood serum samples collected from NHANES participants.

Indicator B6 uses the NHANES data to present median concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) measured in blood serum of women ages 16 to 49 years. These four PFAS were chosen because they are commonly detected in humans, and the bulk of PFAS health effects research in both humans and laboratory animals has focused on these contaminants—especially PFOS and PFOA. However, this indicator does not account for the manufacturing and use of other PFAS which may also result in human exposure. The indicator focuses on women of child-bearing age because of concern for potential adverse effects in children born to women who have been exposed to PFAS.