Table 1.

Half-lives for PFOS, PFHxS and PFOA in longitudinally followed humans

Reference	Setting	Model	Subjects	Initial PFAS level (ng/mL, serum)	Half-life (years)
					PFOS	PFHxS	PFOA
Olsen et al 4	Retired fluorochemical workers, followed 5 years Repeated samplings with batch-wise analysis	First-order elimination First and last sample	22 men, 2 women Age 55–75	Median (range) PFOS: 626 (145–3490) PFHxS: 193 (16–1295) PFOA: 408 (72–5100)	Median 4.6, range 2.4–21.7 GM 4.8 95% CI 4.0 to 5.8	Median 7.1, range 2.2–27.0 GM 7.3 95% CI 5.8 to 9.2	Median 3.4, range 1.5–9.1 GM 3.5 95% CI 3.0 to 4.1
Brede et al 5	Drinking water exposure to PFOA, follow-up 2 years after installation of charcoal filters	First-order elimination First and last sample	20 children 22 mothers 23 men	Median (range) PFOS: ≈9 (2.6–33.3) PFHxS: ≈2.0 (<0.1–2.7) PFOA: ≈24 (6.4–77.5)	(Relative reduction 2006–2008, 22% in women, 25% in men)	(Relative reduction 2006–2008, 30% in women, 14% in men)	GM 3.26 years (range 1.03–14.67) (relative reduction 2006–2008, 39% in women, 25% in men)
Bartell et al 12	Drinking water exposure to PFOA, follow-up after installation of charcoal filter Repeated sampling, follow-up after 1 year	First-order elimination Mixed models, five samples per person	100 men 100 women Age 53±15	Mean, SD PFOA 180±209	–	–	Average 2.3 95% CI 2.1 to 2.4 No sex-dependence
Gomis et al 13	Ski waxers, followed after marked reduction of occupational exposure		4 men	Range 250–1050	–	–	Median 2.4, range 2.0–2.8
Worley et al 11	Drinking water exposure to PFAS, emanating from contaminated sewage sludge applied to agricultural fields; follow-up after 6 years	One-compartment pharmacokinetic model First and last sample	First sample: 63 men, 90 women Average 52 Last sample: 22 men, 23 women	GM PFHxS: 6.4 PFOS: 39.8 PFOA: 16.3	Average 3.3	Average 15.5	Average 3.9

PFHxS, perfluorohexane sulfonate; PFOA, perfluorooctanoate; PFOS, perfluorooctane sulfonate.