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

Half-Life of Serum Elimination of Perfluorooctanesulfonate,Perfluorohexanesulfonate, and Perfluorooctanoate in Retired Fluorochemical Production Workers Geary W. Olsen Jean M. Burris David J. Ehresman John W. Froehlich Andrew M. Seacat John L. Butenhoff Larry R. Zobel

Tag layer of the DHSS Meta-Tagging Project. The article text is reproduced from the staged copy named in sourceDesc and is not altered; the tags are held separately in standOff so that overlapping and nested spans are preserved.

Half-Life of Serum Elimination of Perfluorooctanesulfonate,Perfluorohexanesulfonate, and Perfluorooctanoate in Retired Fluorochemical Production Workers 2007 Environmental Health Perspectives 10.1289/ehp.10009 olsen2007-half-life-of-serum-elimination-of olsen2007-half-life-of-serum-elimination-of.txt, the project's staged copy b35e1c925c0dff176b69a64efca0b24032cdcbed cc-by environmental-science

the paper's own words

the tag layer; a sentence written by the tagger about the paper, always anchored to a quotation but not itself a quotation

0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them the rate at which three perfluoroalkyl acids leave human serum, measured in people whose exposure has stopped Quotation withheld because this record is not cleared for redistribution. how long PFOS, PFHS and PFOA persist in human serum once occupational exposure ends, a number previously available only by extrapolation from monkeys and rodents Quotation withheld because this record is not cleared for redistribution. the first direct human serum elimination half-lives for PFOS, PFHS and PFOA, from 26 retired fluorochemical workers followed for five years Quotation withheld because this record is not cleared for redistribution. existence Quotation withheld because this record is not cleared for redistribution. serum elimination of perfluoroalkyl acids that is slow enough in humans, and fast enough in every other species measured, that the interspecies gap is itself the finding Quotation withheld because this record is not cleared for redistribution. observational-study observational-study Quotation withheld because this record is not cleared for redistribution. a high-affinity transporter returns filtered perfluoroalkyl acid from the renal tubule to the blood; because it saturates, the elimination rate depends on concentration and on how much transporter a species expresses saturable renal resorption Quotation withheld because this record is not cleared for redistribution. species and sexes differ in which proximal-tubule anion transporters they express, so the same molecule is returned to the blood at different rates - offered as the reason the human half-life is years and the rat's is days differential expression of organic anion transporters Quotation withheld because this record is not cleared for redistribution. the C-F bond's stability and the high electronegativity of perfluorinated alkyl acids make metabolism unfavourable, so elimination is the only route of loss and half-life is set entirely by excretion metabolic stability of the carbon-fluorine bond Quotation withheld because this record is not cleared for redistribution. the authors state that human pharmacokinetics is not likely to be one-compartment, in the same discussion that reports half-lives fitted with a one-compartment first-order model - the model is disclaimed and its output is the paper's headline number Quotation withheld because this record is not cleared for redistribution. continuing non-occupational exposure could flatten the observed decline, so the half-lives may be biased long; the paper raises this and does not quantify it Quotation withheld because this record is not cleared for redistribution. the model was selected by looking at a semi-log plot, not by comparing candidate models - linearity by eye is the entire justification for first-order kinetics Quotation withheld because this record is not cleared for redistribution. 26 subjects, 24 of them male, all retired from two plants of one company; the two women are the whole basis for the sex comparison Quotation withheld because this record is not cleared for redistribution. three of the original participants had post-baseline occupational exposure: one was dropped entirely, one truncated, one's start point moved for a single analyte - principled and disclosed, but the cohort is not the cohort recruited Quotation withheld because this record is not cleared for redistribution. first-order elimination kinetics and the half-life construct, carried from single-dose animal pharmacokinetics onto an observational human cohort with no known dose and no defined time zero Quotation withheld because this record is not cleared for redistribution. the renal transporter explanation, carried from rodent sex-difference studies to account for a between-species difference in humans Quotation withheld because this record is not cleared for redistribution. split analyses of the same blood collection, to separate assay variability from real decline eliminates: assay variability being read as a fall in serum concentration, since both halves of the split come from one blood collection · outcome: held Quotation withheld because this record is not cleared for redistribution. spiked recovery and precision at three PFOA concentrations spanning the assay range eliminates: a half-life derived from an assay that is accurate at one concentration and not across the decline it is measuring · outcome: held Quotation withheld because this record is not cleared for redistribution. spiked recovery and precision for PFHS, the analyte with the longest and most variable half-life eliminates: the same, for the analyte whose half-life is longest and most variable and therefore rests on the most measurements · outcome: partial Quotation withheld because this record is not cleared for redistribution. blank rabbit or calf serum run with each batch, to detect contamination in a laboratory that also handled these compounds eliminates: contamination of the samples in a laboratory that also handled these compounds - a blank that comes back clean on each run is what separates measured serum from carry-over · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. end-of-study concentrations checked against general-population reference values, to show the decline was not floored by background exposure eliminates: an elimination rate flattened by continuing background exposure, which would lengthen every half-life in the study · outcome: held Quotation withheld because this record is not cleared for redistribution. the same check applied per subject rather than to the median, which is where it stops holding for four of the 26 eliminates: a median that holds while individuals do not - the per-subject form is where the check stops holding, for four of twenty-six · outcome: partial Quotation withheld because this record is not cleared for redistribution. regression of half-life on age, years worked, job and time since retirement, to test whether the estimate tracks anything about the person rather than the chemistry eliminates: a half-life that tracks age, tenure, job or time since retirement rather than the chemistry of the compound · outcome: held Quotation withheld because this record is not cleared for redistribution. self-reported disease and medication review, for renal or hepatic conditions that would alter clearance eliminates: altered renal or hepatic clearance in a subject being reported as the elimination rate of the compound · outcome: held Quotation withheld because this record is not cleared for redistribution. half-life of serum elimination half-life of serum elimination Quotation withheld because this record is not cleared for redistribution. first-order model first-order model Quotation withheld because this record is not cleared for redistribution. semi-log plot semi-log plot Quotation withheld because this record is not cleared for redistribution. PFOS PFOS Quotation withheld because this record is not cleared for redistribution. PFHS PFHS Quotation withheld because this record is not cleared for redistribution. PFOA PFOA Quotation withheld because this record is not cleared for redistribution. retired fluorochemical production workers retired fluorochemical production workers Quotation withheld because this record is not cleared for redistribution. saturable renal resorption saturable renal resorption Quotation withheld because this record is not cleared for redistribution. organic anion transporters organic anion transporters Quotation withheld because this record is not cleared for redistribution. tubular resorption tubular resorption Quotation withheld because this record is not cleared for redistribution. internal standard internal standard Quotation withheld because this record is not cleared for redistribution. lower limit of quantitation lower limit of quantitation Quotation withheld because this record is not cleared for redistribution. split analyses split analyses Quotation withheld because this record is not cleared for redistribution. linear isomer linear isomer Quotation withheld because this record is not cleared for redistribution. branched chain isomers branched chain isomers Quotation withheld because this record is not cleared for redistribution. cynomolgus monkeys cynomolgus monkeys Quotation withheld because this record is not cleared for redistribution. ion ratios ion ratios Quotation withheld because this record is not cleared for redistribution. environmental exposure environmental exposure Quotation withheld because this record is not cleared for redistribution. rate of elimination rate of elimination Quotation withheld because this record is not cleared for redistribution. right skewness right skewness Quotation withheld because this record is not cleared for redistribution. half-life of serum elimination - the ARITHMETIC mean over the 26 subjects: 5.4 y for PFOS, 8.5 y for PFHS, 3.8 y for PFOA Quotation withheld because this record is not cleared for redistribution. half-life of serum elimination - the GEOMETRIC mean over the same 26 subjects: 4.8 y for PFOS, 7.3 y for PFHS, 3.5 y for PFOA. These are the three numbers later papers quote as the half-life, without naming the statistic Quotation withheld because this record is not cleared for redistribution. half-life of serum elimination - the arithmetic mean after removing the two longest-eliminating subjects, which collapses onto the geometric mean and shows the gap between the first two senses is two people Quotation withheld because this record is not cleared for redistribution. builds-on → Calafat et al.'s NHANES estimates of general-population serum concentrations, used here as the background floor the retirees had to stay above Quotation withheld because this record is not cleared for redistribution. extends → intravenous and repeated-oral-dose pharmacokinetic studies in cynomolgus monkeys, from which human persistence had previously been extrapolated Quotation withheld because this record is not cleared for redistribution. qualifies → one-compartment first-order pharmacokinetic modelling of perfluoroalkyl acids in humans Quotation withheld because this record is not cleared for redistribution. PFHS —contrasted-with→ PFOS PFHS PFOS differs in: human serum elimination half-life and its dispersion · the relation itself is separately evidenced · strength of the relation: 0.9 · differs in (stated by the tagger, no quotation): human serum elimination half-life and its dispersion · the relation stated: eliminates more slowly and more variably Quotation withheld because this record is not cleared for redistribution. retired fluorochemical production workers —contrasted-with→ cynomolgus monkeys retired fluorochemical production workers cynomolgus monkeys differs in: serum elimination half-life of PFOA · the relation itself is separately evidenced · strength of the relation: 0.9 · differs in (stated by the tagger, no quotation): serum elimination half-life of PFOA · the relation stated: eliminate PFOA on a scale of years rather than weeks Quotation withheld because this record is not cleared for redistribution. PFOS —operationalised-as→ ion ratios PFOS ion ratios the relation itself is separately evidenced · strength of the relation: 0.9 · the relation stated: serum concentration is quantified as an ion ratio against a labelled internal standard Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the span says quantification of PFOS was based on ion ratios; operationalised-as is loose. Quotation withheld because this record is not cleared for redistribution. environmental exposure —causes→ rate of elimination environmental exposure rate of elimination direction on the measure: reduces · the relation itself is separately evidenced · strength of the relation: 0.45 — the record marks this weak · direction on the measure (stated by the tagger, no quotation): reduces · the relation stated: continuing background intake would flatten the observed decline, biasing the estimated half-life long Audit 2026-09-28: DOUBTFUL - read against its full span and kept, but the span says it is POSSIBLE that environmental exposure produced shallower slopes; hedged. Quotation withheld because this record is not cleared for redistribution. The human PFOA half-life is considerably longer than in cynomolgus monkeys (about 14-40 days). The human PFOA half-life is considerably longer than in cynomolgus monkeys (about 14-40 days). Quotation withheld because this record is not cleared for redistribution. Excluding the two subjects with the highest half-lives brought the arithmetic means close to the geometric means and medians. Excluding the two subjects with the highest half-lives brought the arithmetic means close to the geometric means and medians. Quotation withheld because this record is not cleared for redistribution. The human PFHS half-life may be longer and more variable than that of PFOS. The human PFHS half-life may be longer and more variable than that of PFOS. Quotation withheld because this record is not cleared for redistribution. no subject characteristic - age, years worked, job, time since retirement - predicts the half-life no subject characteristic - age, years worked, job, time since retirement - predicts the half-life Quotation withheld because this record is not cleared for redistribution. the two female subjects' half-lives are statistically indistinguishable from the men's, on n=2 the two female subjects' half-lives are statistically indistinguishable from the men's, on n=2 Quotation withheld because this record is not cleared for redistribution. the time for serum concentration to halve, estimated per subject from the slope of log concentration against time under an assumed first-order model half-life of serum elimination Quotation withheld because this record is not cleared for redistribution. the lowest acceptable standard value fitted on the standard curves used; 10.0 ng/mL for all analyses regardless of instrument lower limit of quantitation Quotation withheld because this record is not cleared for redistribution. arithmetic mean serum elimination half-life of PFOS 5.4 years Quotation withheld because this record is not cleared for redistribution. geometric mean serum elimination half-life of PFOS - the value cited downstream 4.8 years Quotation withheld because this record is not cleared for redistribution. arithmetic mean serum elimination half-life of PFHS, the longest of the three 8.5 years Quotation withheld because this record is not cleared for redistribution. geometric mean serum elimination half-life of PFHS 7.3 years Quotation withheld because this record is not cleared for redistribution. arithmetic mean serum elimination half-life of PFOA 3.8 years Quotation withheld because this record is not cleared for redistribution. geometric mean serum elimination half-life of PFOA 3.5 years Quotation withheld because this record is not cleared for redistribution. lower limit of quantitation for every analyte and instrument 10.0 ng/mL Quotation withheld because this record is not cleared for redistribution. mean length of follow-up, 5.0 years 1,849 days Quotation withheld because this record is not cleared for redistribution. arithmetic mean arithmetic mean Quotation withheld because this record is not cleared for redistribution. geometric mean geometric mean Quotation withheld because this record is not cleared for redistribution. 95% CI 95% CI Quotation withheld because this record is not cleared for redistribution. Pearson correlation coefficients Pearson correlation coefficients Quotation withheld because this record is not cleared for redistribution. Spearman Rho correlations Spearman Rho correlations Quotation withheld because this record is not cleared for redistribution. multiple regression multiple regression Quotation withheld because this record is not cleared for redistribution. log-normal distribution log-normal distribution Quotation withheld because this record is not cleared for redistribution. CVs CVs Quotation withheld because this record is not cleared for redistribution. initial and end-of-study perfluorochemical concentration initial and end-of-study perfluorochemical concentration Quotation withheld because this record is not cleared for redistribution. age at study onset age at study onset Quotation withheld because this record is not cleared for redistribution. years worked years worked Quotation withheld because this record is not cleared for redistribution. years since retirement years since retirement Quotation withheld because this record is not cleared for redistribution.

The full text of this article is not redistributable, so it is not included here. The evidence sentences are withheld with it; the tag layer and its grounding status remain. The article itself is at https://doi.org/10.1289/ehp.10009.