Bioavailability and bioaccumulation of perfluorinated compounds (PFAS) in a polluted river sediment

Summary

An experiment was performed to contribute to the environmental risk assessment of the perfluorinated compounds (PFAS) in sediments collected nearby a closed down factory in Oppland, Norway. The sediments were placed in replicate aquaria continuously flushed with freshwater. More than 30 different PFAS compounds were analyzed for determination of fluxes from sediment to water and concentrations in sediments, pore water and two benthic species (an oligochaete Tubifex tubifex and a mussel Anodonta anatine) after four weeks exposure in the sediments. Compared to aquaria with control sediments from Lake Årungen and a location in the river upstream of the old factory site, high fluxes and high concentrations of PFAS were found in sediments, pore water and oligochaetes, in aquaria with sediments collected nearby the factory site. Concentrations of PFOS were classified as class III “risk of chronic effects from longterm exposure” at the two most contaminated locations. Concentrations of PFOA did, however, not exceed class II “no toxic effects” in any of the sediments used in this study. By simple division of the estimated sediment reservoir by the fluxes observed in this study, depletion times were obtained ranging from 0.5 years for short chain carboxylates to more than 5000 years for the 12C fluorotelomer. Indications were found that the condition for both oligochaetes and mussels were reduced in the sediments collected in the river adjacent to the factory site. This was more likely due to high concentrations of petrogenic hydrocarbons than high concentrations of PFAS.