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Original Article
Half-lives of PFOS, PFHxS and PFOA after end of exposure to contaminated drinking water
  1. Ying Li1,
  2. Tony Fletcher2,
  3. Daniel Mucs3,
  4. Kristin Scott4,
  5. Christian H Lindh4,
  6. Pia Tallving4,
  7. Kristina Jakobsson1,4
  1. 1 Division of Occupational and Environmental Medicine, Department of Public Health and Community Medicine, University of Gothenburg, Gothenburg, Sweden
  2. 2 Department of Social and Environmental Health Research, London School of Hygiene and Tropical Medicine, London, UK
  3. 3 Swetox, Unit for Toxicological Sciences-Södertälje, Karolinska Institute, Stockholm, Sweden
  4. 4 Division of Occupational and Environmental Medicine, Department of Laboratory Medicine, Lund University, Lund, Sweden
  1. Correspondence to Dr Ying Li, Occupational and Environmental Medicine, University of Gothenburg, SE 405 30 Gothenburg, Sweden;{at}


Background Municipal drinking water contaminated with perfluorinated alkyl acids had been distributed to one-third of households in Ronneby, Sweden. The source was firefighting foam used in a nearby airfield since the mid-1980s. Clean water was provided from 16 December 2013.

Objective To determine the rates of decline in serum perfluorohexane sulfonate (PFHxS), perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA), and their corresponding half-lives.

Methods Up to seven blood samples were collected between June 2014 and September 2016 from 106 participants (age 4–84 years, 53% female).

Results Median initial serum concentrations were PFHxS, 277 ng/mL (range 12–1660); PFOS, 345 ng/mL (range 24–1500); and PFOA, 18 ng/mL (range 2.4–92). The covariate-adjusted average rates of decrease in serum were PFHxS, 13% per year (95% CI 12% to 15%); PFOS, 20% per year (95% CI 19% to 22%); and PFOA, 26% per year (95% CI 24% to 28%). The observed data are consistent with a first-order elimination model. The mean estimated half-life was 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. The interindividual variation of half-life was around threefold when comparing the 5th and 95th percentiles. There was a marked sex difference with more rapid elimination in women for PFHxS and PFOS, but only marginally for PFOA.

Conclusions The estimated half-life for PFHxS was considerably longer than for PFOS and PFOA. For PFHxS and PFOS, the average half-life is shorter than the previously published estimates. For PFOA the half-life is in line with the range of published estimates.

  • pfoa
  • pfhxs
  • pfos
  • half-life

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  • Contributors YL carried out the statistical analyses, interpreted the results and wrote the manuscript. TF interpreted the results and wrote the manuscript. DM reviewed drafts of the manuscript and provided valuable comments for the manuscript. KS participated in the study design, communicated with study participants and managed the data, reviewed the drafts, and provided valuable comments. CHL is responsible for the chemical analysis in the study, reviewed the drafts and provided valuable comments for the manuscript. PT collected the serum samples, communicated with study participants and reviewed the draft. KJ is the principal investigator, led the conceptual and methodological design of the study, and wrote the manuscript. All authors have read and approved the final version of the manuscript.

  • Funding The study was funded by the Swedish Research Council FORMAS (grant reference number 216-2017-1709) and Arbets-och miljömedicin Syd.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval The studies have ethical approval from the Ethics Committee at Lund University, Sweden.

  • Provenance and peer review Not commissioned; externally peer reviewed.