Örebro Studies in Chemistry 25 I
ÖREBRO 2020 2020AL
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alina koch has been a doctoral student in environmental chemistry at the Man-Technology-Environment (MTM) Re-search Centre at Örebro University since 2016. Her reRe-search combined the fields of environmental analytical chemistry and food web ecology to study the fate of a group of organic pollutants, called PFASs, in freshwater environments. Per-and polyfluoroalkyl substances (PFASs) are anthropogenic chemicals of concern, because they have been associated with adverse effects in humans and found their way into the global environment. Most PFASs are highly persistent to degradation and the majority of their emissions are released into aquatic environments. PFASs can easily distribute in water due to their high water solubility and some bioaccumulate in aquatic food webs. Freshwater environments are not self-contained systems, instead inputs and outputs via cross-boundary fluxes, i.e. energy, matter, and food subsidies, are important ecosystem functions. Emergent aquatic insects are essential food subsidies (out-puts) to riparian insectivores such as spiders and birds. The characterization of PFASs and movement via this specific transfer and potential impacts on riparian invertebrate consumers was main focus of this doctoral thesis.
Mainly two freshwater environments in Sweden contaminated by PFAS point sources were investigated. Samples were collected during field campaigns including aquatic insect larvae, emergent aquatic insects, terrestrial consumers and water. Concentrations, homologue and isomer profiles, estimates of mass discharges and bioaccumulation factors of PFASs were used to characterize the distribution of PFASs. Organofluorine mass balance was applied to identify fractions of unknown organofluorine and a PFAS suspect screening analysis was used to identify potential new or overlooked PFASs. The transfer of PFASs was determined by PFAS concentration measured in emergent aquatic insects and their biomass. Additionally invertebrate food web structures were elucidated by stable isotope analysis of carbon and nitrogen.
The major findings from this study demonstrate that PFASs transfer via emer-gent aquatic insects to the riparian zone and some bioaccumulate in riparian insectivores (i.e. PFOS) to that extent that it cloud lead to substantial seasonal impact to the local environment. Organofluorine concentrations could be ex-plained by target PFASs in most aquatic and some terrestrial invertebrates from Ronneby, whereas in surface water ~50% of the organofluorine was unknown. Thus in water most new suspect PFASs were tentatively identified (n = 25).
issn 1651-4270 isbn 978-91-7529-348-6
