A temporal study on unidentified poly- and perfluoroalkyl substances (PFASs) in sewage sludge in Sweden

Sewage treatment plants have been suggested to be one of the major sources of poly- and perfluoroalkyl substances (PFASs) to the aquatic environment. Recent studies have shown more unidentified PFAS were being used and released yearly. Within WWTPs, sorption onto sewage sludge is an important removal mechanism of PFAS from the wastewater. In the current investigation, analysis of archived sludge samples collected from two WWTPs for the period of 2004 and 2015 may provide data on temporal usage of unidentified PFAS. Since sludge may be applied to agricultural field as fertilizer, the results of this project will also give an idea on how much unidentified PFASs present the sludge samples that may enter the environment (ground water) or along food chains (agricultural produce).