Levels of Pfhxs and PFOS in Serum from Drinking Water Exposed Mothers, at Delivery and 12 Years Later

Recently, a drinking water contamination with perfluorinated alkyl acids (PFAAs), mainly perfluorohexane sulfonic acid (PFHxS) and perfluorooctane sulfonic acid (PFOS), was discovered in the City of Uppsala, Sweden. In order to ascertain the impact of this contamination on human blood levels, we investigated blood serum levels of PFHxS and PFOS from 56 women from Uppsala County sampled three weeks after delivery (1996-1999), and 12 years later as a follow-up. Levels of PFHxS and PFOS were analyzed using liquid chromatography/tandem mass spectrometry and the sum of branched isomers and the linear isomer were quantified separately. During the study period the mean serum level of total PFHxS has increased 2.3 times, while the mean level of PFOS has decreased 2.9 times (Table 1). The proportion of branched PFHxS was significantly higher 12 years after delivery compared to the first sampling at three weeks. On the contrary the relative contribution of branched PFOS was significantly lower after 12 years. The o...