Characterisation of PFASs and Organofluorine in Freshwater Environments : Transfer from water to land via emergent aquatic insects

Sammanfattning: Per- and polyfluoroalkyl substances (PFASs) are anthropogenic contaminants of emerging concern, because many are highly persistent to degradation and have been linked to adverse effects in humans as well as their ubiquitous spread in aquatic environments. This thesis investigated distribution of PFASs and organofluorine in freshwater environments impacted by PFAS point sources. The main focus was to study potential transfer of PFASs from freshwater systems to riparian zones via emergent aquatic insects as well as potential impacts on riparian invertebrate consumers.Comprehensive sets of samples, such as aquatic insect larvae, emergent aquatic insects, terrestrial invertebrate consumers and water were collected from mainly two sites in Sweden, Ronneby Airport and Kvarntorp industrial area. Homologue and branched isomer profiles, estimates of mass discharges, bioaccumulation factors, stable isotope analysis of carbon and nitrogen as well as organofluorine mass balance and suspect screening analysis were used to characterize the distribution of PFASs in these freshwater environments including their aquatic and terrestrial invertebrate food webs.Results revealed elevated PFAS concentrations in emergent aquatic insects and riparian invertebrate consumers, especially in spiders. Calculated biodriven transfers indicated that impact on riparian insectivores could be substantial on a local and seasonal scale. Furthermore, PFAS concentrations in terrestrial consumers were related to aquatic-based diet and trophic levels, indicating that biomagnification was a major pathway of uptake for some PFASs. Organofluorine mass balance could be closed for most aquatic and for some terrestrial invertebrates from the Ronneby site by target PFAS analysis, whereas a fraction of ~50% in surface water was unidentified organofluorine. Most new PFASs, tentatively identified by suspect screening, were found in water samples and given that contamination occurred decades ago suggested that those PFASs, mainly perfluoroalkyl sulfonamide-based PFASs, are highly water soluble and persistent.