Epsilon Archive for Student Projects

Abstract

Per- and polyfluoroalkyl substances (PFASs) is a group of persistent, bioaccumulative and toxic pollutants. PFASs are widely used in industrial processes and products such as water- and fat repelling surfaces in clothes, paints and paper. They are also used in certain types of firefighting foams and have been found in ski waxes. PFASs are organic compounds with a fully or partly fluorinated chain which makes them very stable to heat and degradation. They are globally spread and found in high concentrations in e.g. water and biota.

The goal of this study was to analyze the results from a screening campaign of PFASs in Swedish waters. The aims were to identify the most polluted types of waters and identify the main emission sources. Further, the measured concentrations were compared with guideline values. This study also investigated the possibility of tracing PFAS sources from a water sample.

In total 528 samples (including 30 triplicates and 26 blanks) were collected across Sweden and analyzed for 26 different PFASs. The types of water sampled were groundwater, surface water, landfill leachate and sewage treatment plant (STP) effluent. Also 10 reference lakes located in remote areas were sampled. The samples were analyzed by using a method including filtration, SPE (solid phase extraction) and LC-MS/MS (liquid chromatography- tandem mass spectrometry).

The result showed PFAS concentrations ranging from zero to thousands of ng L-1. The highest average concentration was measured in landfill leachate. The maximum concentrations were detected in samples collected from surface water and groundwater.

The impact from different sources was investigated for surface- and groundwater. The results showed that fire training sites are causing the highest concentrations followed by landfills/waste disposal areas. An analysis of the concentration in drinking water showed that 5 of the sampled sites contained concentrations above the recommended guidelines from the Swedish National Food Agency (90 ng L-1 for the sum of 11 PFASs). The conclusion drawn from this was that it is important to continue monitoring PFAS concentrations in drinking water sources, especially those potentially impacted by fire training sites or landfills.

The possibility of source tracing PFASs from surface- and groundwater samples was investigated through PCA (Principal Component Analysis), cluster analysis and analysis of branched isomers. The results did not show any correlations between the sources and specific PFAS profiles, except for PFOS, PFBS, PFHxS and PFPeA in groundwater which showed some correlation with fire training sites. The conclusion was that source tracing needs to be investigated further, and the possibility of finding correlations might increase if more specific source categories are used.