Half-lives of PFOS, PFHxS and PFOA after end of exposure to contaminated drinking water.
Level 3 - non-randomized controlled study
Prospective longitudinal cohort study tracking biomarker clearance over time.
PubMed 29133598 · doi:10.1136/oemed-2017-104651
What was done
Following the supply of clean water starting December 16, 2013, after municipal drinking water contamination with firefighting foam in Ronneby, Sweden, researchers tracked the decline of serum perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS), and perfluorooctanoate (PFOA). Up to seven blood samples were obtained between June 2014 and September 2016 from 106 participants aged 4 to 84 years (53% female).
What was found
Initial median serum concentrations were 277 ng/mL (range 12–1660) for PFHxS, 345 ng/mL (range 24–1500) for PFOS, and 18 ng/mL (range 2.4–92) for PFOA. Covariate-adjusted annual rates of serum decline were 13% (95% CI 12% to 15%) for PFHxS, 20% (95% CI 19% to 22%) for PFOS, and 26% (95% CI 24% to 28%) for PFOA, matching a first-order elimination model. Mean estimated half-lives were 5.3 years (95% CI 4.6 to 6.0) for PFHxS, 3.4 years (95% CI 3.1 to 3.7) for PFOS, and 2.7 years (95% CI 2.5 to 2.9) for PFOA. Interindividual variation spanned approximately threefold between the 5th and 95th percentiles. Women exhibited more rapid elimination of PFHxS and PFOS, but only marginally faster elimination of PFOA.
Why it matters
This study provides empirical clearance kinetics after real-world cessation of high-level PFAS drinking water contamination, showing that PFHxS persists longer than PFOS and PFOA, with shorter average half-lives for PFHxS and PFOS than previously published estimates.
Limits
Follow-up was relatively short (June 2014 to September 2016, approximately 2.3 years) compared to the multi-year half-lives being calculated. The sample size was modest (n=106) from a single geographic contamination event, and potential ongoing low-level background exposures or unmeasured dietary sources were not detailed in the abstract.
Cited by
- supports PFAS chemicals accumulate in human organs including the liver and kidneys.