Table 5.
Subsurface-soil concentration metrics for select PFAS retrieved from the U.S. Air Force AFFF Impacted-Site database. All values are reported in μg/kg. See footnote for PFAS descriptions. Samples include all data excluding the data presented in Table 4.
| Metric | PFBA | PFHxA | PFOA | PFDA | PFBS | PFHxS | PFOS | PFDS | PFOSA | 6:2 FTSA |
|---|---|---|---|---|---|---|---|---|---|---|
| Range | 0.07-170 | 0.07-2700 | 0.05-7220 | 0.0005-285 | 0.05-940 | 0.06-15300 | 0.1-160000 | 0.05-110 | 0.07-2500 | 0.2-21000 |
| Median | 0.6 | 1.8 | 2.0 | 0.5 | 1.3 | 4.9 | 10 | 0.7 | 1.5 | 4.3 |
| Geometric Mean | 0.7 | 2.5 | 2.9 | 0.6 | 1.8 | 5.7 | 12 | 1.1 | 2.1 | 5.4 |
| Number of Samples | 947 | 1934 | 2881 | 360 | 1619 | 3825 | 4259 | 184 | 406 | 854 |
| Surface/Subsurface Geomeansa | 1.4 | 0.8 | 0.7 | 1.8 | 0.8 | 0.8 | 1.8 | 2.1 | 1.8 | 1.2 |
a
ratio of geometric means for surface samples vs subsurface samples
PFBA=perfluorobutanoic acid; PFHxA=perfluorohexanoic acid; PFOA=perfluorooctanoic acid; PFDA=perfluorodecanoic acid; PFBS=perfluorobutanesulfonic acid; PFHxS=perfluorohexanesulfonic acid; PFOS=perfluorooctanesulfonic acid; PFDS=perfluorodecanesulfonic acid; PFOSA=perfluorooctanesulfonamide; 6:2 FTSA= 6:2 fluorotelomer sulfonic acid