NHANES PFAS Biomonitoring
The National Health and Nutrition Examination Survey (NHANES) has measured PFAS in blood serum from a nationally representative U.S. population sample continuously since 1999, providing the most comprehensive longitudinal biomonitoring dataset for PFAS in any country. NHANES PFAS data have documented declining trends for PFOA and PFOS following regulatory phase-outs, while revealing rising levels of replacement PFAS including PFHxS, PFNA, and PFBS.
NHANES blood PFAS levels are measured using immunoassay and LC-MS/MS methods with detection limits in the low ppt (sub-1 ng/mL) range. The survey includes approximately 5,000 people annually, with PFAS measured in subsamples of 1,000–2,000 participants. Data are publicly available for research and regularly updated.
Key Findings from National Biomonitoring
NHANES data show that virtually all Americans have detectable PFAS in their blood. Geometric mean PFAS levels vary by age, sex, race/ethnicity, and geography — with older adults having higher levels due to lifetime accumulation, women having higher levels of certain PFAS related to consumer products, and communities near industrial sources showing distinctly elevated levels compared to national averages.
The declining trend in PFOA and PFOS blood levels since the early 2000s demonstrates that regulatory phase-outs and changes in product composition have measurably reduced population exposure. However, the concurrent rise in short-chain and next-generation PFAS replacement compounds shows that total PFAS body burden has not declined commensurately — the compounds have shifted, not decreased.
State Biomonitoring Initiatives
Several states — including California, Michigan, Minnesota, and New York — have implemented state-specific PFAS biomonitoring programs to characterize exposure in their populations and near specific contamination sources. These programs complement federal NHANES data by providing geographically targeted sampling near contaminated sites and including additional PFAS compounds not measured in NHANES.
Community-based biomonitoring programs — where residents in contaminated areas can have their blood PFAS levels tested — are increasingly offered by state health departments and universities. These programs empower individuals with knowledge of their personal exposure, connect residents to health surveillance programs, and generate data for community-level PFAS exposure characterization.