Half-Life of Serum Elimination of Perfluorooctanesulfonate,Perfluorohexanesulfonate, and Perfluorooctanoate in Retired Fluorochemical Production Workers

TLDR

There are 4 labels present. Let's collect: Background: lines with [Background] or [Background, Purpose, Mechanism] or [Background] again. Content: Line1: "BackgroundThe presence of perfluorooctanesulfonate (PFOS), perfluorohexanesulfonate (PFHS), and perfluorooctanoate (PFOA) has been reported in humans and wildlife." Line2: [Background, Purpose, Mechanism] includes "Pharmacokinetic differences have been observed in laboratory animals." plus "ObjectiveThe purpose of this observational study was to estimate the elimination half-life of PFOS, PFHS, and PFOA from human serum." plus "MethodsTwenty-six (24 male, 2 female) retired fluorochemical production workers, with no additional occupational exposure, had periodic blood samples collected over 5 years, with serum stored in plastic vials at −80°C." Line5: [Background] "Differences in species-specific pharmacokinetics may be due, in part, to a saturable renal resorption process." So background content: presence of PFOS, PFHS, PFOA in humans and wildlife; pharmacokinetic differences observed in lab animals; species-specific PK differences may be due to saturable renal resorption. Purpose: from [Background, Purpose, Mechanism] line: "ObjectiveThe purpose of this observational study was to estimate the elimination half-life of PFOS, PFHS, and PFOA from human serum." Mechanism: multiple lines: [Background, Purpose, Mechanism] includes Methods: "MethodsTwenty-six (24 male, 2 female) retired fluorochemical production workers, with no additional occupational exposure, had periodic blood samples collected over 5 years, with serum stored in plastic vials at −80°C." Also [Mechanism] line: "At the end of the study, we used HPLC-mass spectrometry to analyze the samples, with quantification based on the ion ratios for PFOS and PFHS and the internal standard 18O2-PFOS." [Mechanism, Findings] line: "For PFOA, quantitation was based on the internal standard 13C2-PFOA." [Mechanism] line: "For each of the 26 subjects, the elimination appeared linear on a semi-log plot of concentration versus time; therefore, we used a first-order model for estimation." So mechanism: 26 retired workers, serial blood sampling over 5 years, stored at -80°C, analysis by HPLC-MS with specific internal standards, linear elimination modeled by first-order kinetics.

Abstract

BackgroundThe presence of perfluorooctanesulfonate (PFOS), perfluorohexanesulfonate (PFHS), and perfluorooctanoate (PFOA) has been reported in humans and wildlife. Pharmacokinetic differences have been observed in laboratory animals.ObjectiveThe purpose of this observational study was to estimate the elimination half-life of PFOS, PFHS, and PFOA from human serum.MethodsTwenty-six (24 male, 2 female) retired fluorochemical production workers, with no additional occupational exposure, had periodic blood samples collected over 5 years, with serum stored in plastic vials at −80°C. At the end of the study, we used HPLC-mass spectrometry to analyze the samples, with quantification based on the ion ratios for PFOS and PFHS and the internal standard 18O2-PFOS. For PFOA, quantitation was based on the internal standard 13C2-PFOA.ResultsThe arithmetic mean initial serum concentrations were as follows: PFOS, 799 ng/mL (range, 145–3,490); PFHS, 290 ng/mL (range, 16–1,295); and PFOA, 691 ng/mL (range, 72–5,100). For each of the 26 subjects, the elimination appeared linear on a semi-log plot of concentration versus time; therefore, we used a first-order model for estimation. The arithmetic and geometric mean half-lives of serum elimination, respectively, were 5.4 years [95% confidence interval (CI), 3.9–6.9] and 4.8 years (95% CI, 4.0–5.8) for PFOS; 8.5 years (95% CI, 6.4–10.6) and 7.3 years (95% CI, 5.8–9.2) for PFHS; and 3.8 years (95% CI, 3.1–4.4) and 3.5 years (95% CI, 3.0–4.1) for PFOA.ConclusionsBased on these data, humans appear to have a long half-life of serum elimination of PFOS, PFHS, and PFOA. Differences in species-specific pharmacokinetics may be due, in part, to a saturable renal resorption process.