. 2020 Jul 10;128(7):077004. doi: 10.1289/EHP6785

Table 7.

Individual constant elimination rate (yearly) and half-life (year) in the 17 airport employees for long-chain PFAS.

Subject	Sample counts	PFOA			PFHxS			PFHpS			L-PFOS			1m-PFOS			3/4/5m-PFOS			2/6m-PFOS
Subject	Sample counts	Elimination rate^a	HL^a	$p$ -Value^a	Elimination rate	HL	$p$ -Value	Elimination rate	HL	$p$ -Value	Elimination rate	HL	$p$ -Value	Elimination rate	HL	$p$ -Value	Elimination rate	HL	$p$ -Value	Elimination rate	HL	$p$ -Value
1	5	0.3	2.4	0.17	0.2	3.5	0.19	0.5	1.3	0.31	$- 0.2$	NA	0.30	0.3	2.0	0.10	0.4	1.9	0.13	$- 0.2$	NA	0.76
2	5	0.2	2.9	0.27	0.3	2.0	0.09	0.2	3.4	0.64	0.4	1.7	0.07	0.1	5.4	0.83	0.3	2.1	0.11	0.5	1.3	0.20
3	5	0.6	1.2	0.04	0.5	1.5	0.09	0.2	3.0	0.34	0.5	1.3	0.21	0.8	0.9	0.09	0.4	1.7	0.15	0.7	1.0	0.12
4	5	0.3	2.3	0.15	0.1	9.6	0.75	0.001	526	1.00	$- 0.3$	NA	0.24	$- 0.1$	NA	0.78	0.1	11	0.87	0.0	51	0.97
5	5	0.3	2.2	0.15	0.1	4.7	0.20	$- 0.3$	NA	0.19	0.6	1.2	0.13	0.1	5.9	0.75	0.2	3.1	0.16	0.4	1.6	0.56
6	4	0.2	2.9	0.39	$- 0.1$	NA^b	0.42	0.1	6.1	0.43	0.04	17	0.87	$- 0.1$	NA	0.51	0.04	19	0.49	0.4	1.7	0.04
7	5	0.4	1.6	0.03	0.3	2.3	0.02	$- 0.04$	NA	0.88	0.006	108	0.92	$- 0.3$	NA	0.03	0.1	4.8	0.02	1.1	0.6	0.29
8	5	0.007	100	0.98	$- 0.01$	NA	0.94	$- 0.6$	NA	0.42	$- 0.4$	$- 1.6$	0.23	$- 0.5$	NA	0.13	$- 0.2$	NA	0.24	$- 0.2$	NA	0.44
9	5	0.4	1.9	0.05	$- 0.04$	NA	0.81	0.05	15	0.69	0.4	1.8	0.21	$- 0.3$	NA	0.10	0.1	10	0.70	0.2	4.2	0.50
10	5	0.3	2.1	0.25	0.4	1.9	0.11	0.4	1.8	0.46	$- 0.2$	NA	0.32	0.6	1.2	0.10	0.2	4.0	0.52	$- 0.007$	NA	0.97
11	5	0.5	1.5	0.12	0.2	3.0	0.39	1.7	0.4	0.20	0.1	4.7	0.56	1.9	0.4	0.15	2.0	0.4	0.15	1.7	0.4	0.10
12	5	0.7	1.0	0.00	0.4	1.6	0.04	0.6	1.1	0.08	0.8	0.9	0.01	0.03	26	0.95	0.5	1.3	0.09	1.7	0.4	0.03
13	5	0.4	1.6	0.02	0.5	1.4	0.01	$- 0.2$	NA	0.70	0.2	3.7	0.34	1.1	0.6	0.08	0.5	1.5	0.04	1.0	0.7	0.20
14	4	0.4	1.6	0.40	0.6	1.2	0.31	1.0	0.7	0.21	0.3	2.0	0.67	1.7	0.4	0.08	0.3	2.0	0.55	1.5	0.5	0.44
15	5	0.6	1.1	0.04	0.3	2.2	0.06	1.6	0.4	0.09	0.5	1.3	0.01	1.3	0.6	0.18	2.2	0.3	0.08	1.2	0.6	0.18
16	5	0.3	2.7	0.19	0.04	19	0.89	0.1	12	0.61	0.6	1.2	0.05	$- 0.3$	NA	0.02	0.3	2.0	0.12	$- 0.1$	NA	0.81
17	5	0.6	1.2	0.09	0.4	1.6	0.07	1.7	0.4	0.13	0.3	2.1	0.19	2.2	0.3	0.12	1.9	0.4	0.13	1.9	0.4	0.10

Note: HL, half-life; L-PFOS, linear perfluorooctane sulfonic acid; PFAS, perfluoroalkyl substances; PFHpS, perfluoroheptane sulfonic acid; PFHxS, perfluorohexane sulfonic acid; PFOA, perfluorooctanoic acid; 1m-PFOS, branched, perfluoro-1-methylheptanesulfonate; 2/6m-PFOS, branched, sum of perfluoro-2/6-methylheptanesulfonate; 3/4/5m-PFOS, branched, sum of perfluoro-3/4/5-methylheptanesulfonate.

^{^a}

The elimination rate and $p$ -value were obtained from linear regression. Serum PFAS levels were log-transformed. The elimination rate denotes the negative value of the slope ( $- β$ ) from the model, and half-life is calculated as $ln 2 / k$ .

^{^b}

Not applicable because the elimination rate was negative, indicating PFAS levels did not decrease during the 5-month follow-up.