Table 2.

PFAS Concentrations in archived tap water samples collected from the Nurses’ Health Study (NHS) participants’ residences in 1989–1990 ($n=225$).

	$>\text{LOD}$ $n$ (%)	Median (IQR)a [ng/L]	Max [ng/L]
PFCAs
PFPeA	84 (37)	0.61 (0.13, 1.72)	62.6
PFHpA	69 (31)	0.71 (0.35, 1.15)	9.65
nPFOA	134 (60)	0.57 (0.33, 1.36)	92.8
brPFOA	64 (28)	0.39 (0.17, 0.51)	12.0
nPFNA	62 (28)	0.23 (0.13, 0.29)	17.9
brPFNA	22 (10)	0.19 (0.10, 0.34)	16.1
PFDAb	43 (19)	0.22 (0.19, 0.94)	27.6
PFUnDA	109 (48)	1.15 (0.32, 2.42)	48.4
PFDoDA	76 (34)	2.31 (0.47, 6.40)	51.0
PFSAs
PFBSb	12 (5)	0.20 (0.19, 0.25)	2.97
nPFHxS	134 (60)	0.51 (0.23, 1.43)	28.0
brPFHxS	76 (34)	0.44 (0.18, 0.99)	4.93
nPFOS	107 (48)	0.69 (0.29, 1.80)	66.5
brPFOS	77 (34)	0.94 (0.51, 2.04)	18.7
PFDSc	27 (12)	0.11 (0.08, 0.52)	35.8

^aMedian (IQR) were calculated for samples $>\text{LOD}$ only.

^bPFDA and PFBS were excluded from subsequent analyses due to the proportion of nondetects.

^cPFDS was excluded from further analyses due to low recovery rate, even though its detection frequency is low as well.