Determinants of serum half-lives for linear and branched perfluoroalkyl substances after long-term high exposure-A study in Ronneby, Sweden.
Level 3 - non-randomized controlled study
Longitudinal observational follow-up cohort study tracking serum elimination kinetics over time.
PubMed 35447437 · doi:10.1016/j.envint.2022.107198
What was done
A longitudinal study evaluated 114 individuals (ages 4 to 84 years, 53% female) in Ronneby, Sweden, who experienced long-term exposure to municipal drinking water contaminated with PFAS from firefighting foam until clean water was introduced in December 2013. Up to 10 blood samples were collected per participant between 2014 and 2018. Serum concentrations of 19 PFAS compounds were analyzed, and linear mixed models were applied to estimate elimination half-lives and investigate physiological determinants of clearance.
What was found
Eight PFAS were elevated in the study population. Mean estimated serum half-lives (in years, with 95% confidence intervals) were: PFPeS 0.94 (0.86 to 1.02), PFOA 2.47 (2.27 to 2.70), 2/6m-PFOS 2.67 (2.51 to 2.85), L-PFOS 2.73 (2.55 to 2.92), 3/4/5m-PFOS 3.43 (3.19 to 3.71), PFHxS 4.52 (4.14 to 4.99), PFHpS 4.55 (4.14 to 5.06), and 1m-PFOS 5.01 (4.56 to 5.55). Shorter half-lives were primarily associated with younger age, higher estimated glomerular filtration rate, higher urine-to-serum PFAS ratios, and female sex during childbearing years (aged 15 to 50). Gut inflammation and permeability markers (zonulin and calprotectin) were also possibly associated with shorter half-lives. Elimination was faster during the first year after exposure ceased.
Why it matters
This study provides precise human elimination kinetics for both linear and branched PFAS isomers and supports renal, fecal, and maternal clearance as active elimination pathways in humans.
Limits
The study was conducted in a relatively small sample (n=114) from a single community with exceptionally high historical exposure, which may not directly generalize to low-dose general population kinetics. Potential background dietary or environmental PFAS re-exposure during follow-up was not fully controlled.
Cited by
- supports PFAS chemicals have an elimination half-life in the human body of 2 to 5 years.