PFAS in the water supply: source water contamination

Abstract: Water contamination with per- and polyfluoroalkyl substances (PFAS) is a serious problem for water suppliers in many regions. Due to persistence of the substances and a complex distribution mechanism, PFAS can have an adverse impact on water quality. Reported toxicological and health effects, make it very important to minimise the of wildlife and human exposure to PFAS. The exposure path is, however, associated with the most vital resource as water.Mitigation of the PFAS contamination is an extensive challenge that requires a multidisciplinary investigation of the pollution nature and distribution mechanisms in the aquatic environment. Furthermore, since conventional drinking water treatment is insufficient in PFAS removal, development of the treatment alternative is necessary. Not least due to substantial number of contaminated water sources and an increasing worldwide demand on drinking water.Present thesis was built around investigation of the historical source water contamination and human exposure to PFAS at studied locations in Ronneby (primarily) and Luleå in Sweden. Several interconnected studies were conducted regarding present contamination levels, transport and distribution mechanism, contamination and emission history, as well as PFAS treatment alternatives for drinking water.PFAS analysis and assessment of the contamination levels in surface water, groundwater, and sediments were conducted. PFAS occurrence at studied locations was connected to historical use of PFAS containing aqueous film forming foam (PFAS-AFFF). By means of core analysis, accumulation period was studied for the exposed recipient (Lake). Furthermore, influence of the media characteristics (i.e., mineral composition, density, moisture, and organic matter content) on PFAS distribution in sediment was studied and corresponding distribution (partitioning) predictors were estimated. Regarding emission source, profiling of the possible PFAS-AFFF compositions was conducted (based on groundwater analysis), and possible application and emission scenarios were evaluated (based on available fire-training history and related protocols). Investigation of PFAS treatment methods for drinking water was conducted and implementation of ex-situ treatment technique, based on UVC/VUV induced removal, was suggested. The laboratory scale treatment unit was developed and tested in series of experimental trials with PFCAs, PFSAs, FTSAs, and FASAs.