Contribution of precursor compounds to the release of per-and polyfluoroalkyl substances(PFASs) from waste water treatment plants(WWTPs)

Per-and polyfluoroalkyl substances（PFASs） are ubiquitous in sludge and water from waste water treatment plants, as a result of their incorporation in everyday products and industrial processes. In this study, we measured several classes of persistent PFASs,precursors, transformation intermediates, and newly identified PFASs in influent and effluent sewage water and sludge from three municipal waste water treatment plants in Sweden, sampled in 2015. For sludge, samples from 2012 and 2014 were analyzed as well.Levels of precursors in sludge exceeded those of perfluoroalkyl acids and sulfonic acids（PFCAs and PFSAs）, in 2015 the sum of polyfluoroalkyl phosphoric acid esters（PAPs） were 15–20 ng/g dry weight, the sum of fluorotelomer sulfonic acids（FTSAs） was 0.8–1.3 ng/g,and the sum of perfluorooctane sulfonamides and ethanols ranged from non-detected to 3.2 ng/g. Persistent PFSAs and PFCAs were detected at 1.9–3.9 ng/g and 2.4–7.3 ng/g dry weight, respectively. The influence of precursor compounds was further demonstrated by an observed substantial increase for a majority of the persistent PFCAs and PFSAs in water after waste water treatment. Perfluorohexanoic acid（PFHxA）, perfluorooctanoic acid（PFOA）, perfluorohexane sulfonic acid（PFHxS）, and perfluorooctane sulfonic acid（PFOS）had a net mass increase in all WWTPs, with mean values of 83%, 28%, 37% and 58%,respectively. The load of precursors and intermediates in influent water and sludge combined with net mass increase support the hypothesis that degradation of precursor compounds is a significant contributor to PFAS contamination in the environment.

Perfluoroalkyl substances in the blood samples from a male population of Sweden

Temporal trends of perfluoroalkyl substances(PFASs)have been determined in the blood samples from several countries globally including a female population in Sweden recently,yet little is known about the time trends in the blood levels of these compounds in Swedish male populations over recent years.In this study,the fourteen target PFASs consisted of four perfluorosulfonates(PFSAs)and ten perfluorocarboxylates(PFCAs)in the whole blood samples,collected from 153 Swedish elderly men during the period between 2008 and 2010,were analyzed via ultra-performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS).As the dominant PFASs contaminants in the blood samples,perfluorooctane sulfonate(PFOS)showed the highest geometric mean(GM)at8.5 ng/mL,ranging from 1.7 to 29 ng/mL,while blood perfluorooctanoic acid(PFOA)contained the GM of1.8 ng/mL,ranging from 0.35 to 6.4 ng/mL.Both the levels of these two compounds were lower than those determined in the blood samples of Swedish elderly populations derived from the late 1990s.According to the temporal trend analysis,over the three years,the blood levels of PFOS in Swedish male populations declined 16% per annum,while those of perfluoroundecanoic acid(PFUnDA)increased 6.1%per annum,which were consistent with those reported previously for the populations from other countries.