Table 2.

Description of the 26 airport employees and PFAS levels measured in the first serum samples, together with PFAS levels measured in the reference group.

Categories	Employees participated in first blood sampling only	Employees participated in first blood sampling and repeated blood and urine sampling	Reference groupa
Basic characteristics
Counts (N)	9	17	58
Female [N (%)]	1 (11)	6 (35)	37 (64)
Age [median (range)]	33 (22–61)	50 (24–62)	34 (22–49)
Years of current employment [median (range)]	2 (1–27)	10 (1–28)	NAb
Total working days from 1 August to 11 September 2018 [median (range)]	29 (1–40)	39 (20–42)	NA
Pregnancy previously [yes (%)]	1 (100)	2 (33)	NA
Year of last pregnancy	2018	2010 and 1999	NA
Month of breast-feeding (median)	6	Both 6	NA
PFCAs in first serum sample {$\text{ng}/\mathrm{mL}$ [median (range)]}c
PFHxA (C6)	0.38 (0.23–1.1)	0.37 (0.16–0.92)	NA
PFHpA (C7)	0.17 (0.07–1.3)	0.53 (0.20–2.2)	NA
PFOA (C8)	6.5 (2.9–11)	13 (5.0–31)	1.5 (0.26–4.6)
PFSAs in first serum sample {$\text{ng}/\mathrm{mL}$ [median (range)]}
PFBS (C4)	0.10 ($<\text{LOD}$–1.0)d	0.46 (0.22–1.3)	NA
PFPeS (C5)	3.5 (1.4–11)	7.6 (3.6–17)	$<\text{LOD}$ ($<\text{LOD}$–0.02)
PFHxS (C6)	60 (17–85)	133 (21–402)	0.59 ($<\text{LOD}$–1.2)
PFHpS (C7)	0.97 (0.28–1.9)	1.6 (0.49–6.2)	$<\text{LOD}$ ($<\text{LOD}$–0.16)
L-PFOS (C8)	6.5 (5.4–13)	11 (5.5–28)	3.0 (0.30–9.8)
1m-PFOS (C8)	0.52 (0.25–2.7)	1.0 (0.32–4.1)	0.18 ($<\text{LOD}$–0.59)
3/4/5m-PFOS (C8)	2.9 (1.2–6.7)	4.9 (1.7–17)	0.79 (0.10–2.2)
2/6m-PFOS (C8)	1.8 (0.84–3.2)	2.6 (1.0–7.5)	0.46 ($<\text{LOD}$–1.4)

Note: L-PFOS, linear perfluorooctane sulfonic acid; LOD, limit of detection; PFAS, perfluoroalkyl substances; PFBS, perfluorobutane sulfonic acid; PFCA, perfluorinated carboxylic acid; PFHpA, perfluoroheptanoic acid; PFHpS, perfluoroheptane sulfonic acid; PFHxA, perfluorohexanoic acid; PFHxS, perfluorohexane sulfonic acid; PFOA, perfluorooctanoic acid; PFPeS, perfluoropentane sulfonic acid; PFSA, perfluorinated sulfonic 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.

^aThe reference group was from Karlshamn, Sweden, a municipality without PFAS contamination in drinking water (Li et al. 2018). This group was sampled in 2016. A subset of 59 individuals were randomly selected for analyzing other short-chain PFAS than the legacy ones using the same method as the airport employees, and 58 within the same age range as the airport employees (i.e., 22–62 years of age) were included in the comparison.

^bNo data available or PFAS was not measured.

^cPFBA and PFPeA were elevated in the drinking water (Table 1) but below the LOD in all the serum samples, so they were not presented in the present paper.

^dLODs are listed in Table S3.