Perfluoroalkyl Substances (PFASs) in the Canadian Freshwater Environment.

Abstract Per- and polyfluoroalkyl substances (PFASs) are anthropogenic substances that are very stable in the receiving environment. PFASs are persistent and resistant to typical environmental degradation processes and therefore are distributed across all trophic levels and environmental compartments (soil, air, water). Since most uses of PFOS, PFOA and LC-PFCAs are banned in Canada, alternative PFASs have been in use for a number of years. Twenty-nine sites across Canada were sampled for PFASs to determine concentrations and trends. Overall, 13 PFASs were measured in 566 Canadian freshwater samples from 2013- 2020 with a range from below the detection limit of the laboratory to a maximum of 138 ng/L (for PFBS). While PFOS and PFOA concentrations are declining significantly over time, other compounds such as PFPeA and PFBA have increased significantly over 2013-2020. Overall the range of concentrations found in this study were similar to that of other Canadian and international studies. However, this study also found a higher frequency of detections of the replacement PFASs than that of the other, older, Canadian studies.