Technical Report - Half-lives of PFOS, PFHxS and PFOA after end of exposure to contaminated drinking water

The present knowledge on PFAS elimination in humans after the end of a dominating source of exposure is scarce. For PFOS and PFHxS only data from fluorochemical workers exist, while a few studies in general populations have reported data for PFOA after end of exposure by drinking water. We here report the first results of analyses of half-life for PFOS, PFHxS and PFOA in a Swedish general population with high exposure in drinking water following cessation of exposure, and compare with hitherto unpublished data on PFOS and PFOA elimination from the C8 study in Ohio, USA. Among 106 persons observed between 6 and 33 months after end of exposure to contaminated drinking water, the shortest half-life was observed for PFOA, mean 2.7 years. The half-life for PFHxS was twice as long, 5.3 years. For PFOS the mean was 3.4 years. The interindividual variation was substantial, with a threefold difference between the 5 and 95 percentiles. In addition, there were also a few extreme outliers. The estimates are well in line with observations in retired fluorocarbon workers, and with observations on PFOA half-live from the C8 study