Source analysis of perfluorocarboxylates in Tokyo Bay during dry weather and wet weather using sewage markers

Abstract

Environmental contextAs perfluorocarboxylates can be carried by surface runoff to waters and cause adverse effects to aquatic organisms, we evaluated the contributions of wastewater and surface runoff to the concentrations of these compounds in Tokyo Bay during dry and wet weather. Sewage markers revealed that the surface runoff was a significant source of perfluorocarboxylates in the bay during wet weather. This finding leads to a greater understanding of sources and pathways of perfluorocarboxylates in waters. AbstractWe investigated the occurrence of perfluorocarboxylates (PFCAs) in Tokyo Bay during dry and wet weather and evaluated the contributions of wastewater effluent, untreated wastewater, and surface runoff by using two sewage markers, caffeine and crotamiton. ∑8PFCAs ranged from 11 to 185 ng L–1. Perfluorononanoate (PFNA) was the major species, followed by perfluorooctanoate (PFOA) and perfluoroheptanoate (PFHpA). Principal component analysis followed by multiple linear regression revealed that the PFCAs were derived mainly from wastewater effluent during dry weather, and jointly from wastewater effluent (59%) and combined sewer overflow (41%) during wet weather. We used caffeine-to-crotamiton ratios to evaluate the contributions of untreated wastewater and wastewater effluent. Estimated concentrations of wastewater-derived PFCAs were much lower than observed concentrations during wet weather, indicating the contribution of surface runoff to contamination. During a combined sewer overflow, surface runoff had a significant effect on contamination in the bay.