Existence of nonpoint source of perfluorinated compounds and their loads in the Tsurumi River basin, Japan

Products containing perfluorinated compounds (PFCs) have been widely used during the last 50 years. As a result, worldwide environmental pollution by PFCs has been reported. The sources of PFC pollution in the aquatic environment have been poorly understood. In this study, river water and sewage treatment plant (STP) effluent were sampled along the stretch of the Tsurumi River and also at a fixed station in the river. The concentrations of perfluorooctanesulfonate (PFOS), perfluorohexanoic acid (PFHxA), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were measured. With an increase in river flow rate, it was observed that the PFC concentrations in the river water at fixed station were remained the same or increased for PFOS (179.9 ± 34.4–179.6 ± 69.5 ng l−1), PFHxA (5.5 ± 0.8–9.0 ± 2.6 ng l−1), PFHpA (3.1 ± 0.3–4.4 ± 1.0 ng l−1), and PFOA (15.9 ± 0.3–13.4 ± 2.5 ng l−1) whereas the concentration of PFNA (38.0 ± 3.3–15.4 ± 3.0 ng l−1) and PFDA (3.9 ± 0.3–2.1 ± 0.3 ng l−1) were decreased. On the other hand, the loads of every PFC increased with an increase in river flow rate. The loads of PFCs in rain runoff were estimated to be 2–11 times greater than those in STP effluents that are discharged into the river. These results indicate the existence of a PFC nonpoint source (NPS) and its impact to the total PFC load of river is significant.