Measurements of direct inputs of fluorochemicals to the environment via the discharge of municipal wastewater treatment plant (WWTP) effluents indicate that WWTPs are point sources of fluorochemicals. Municipal wastewaters contain fluorochemicals due to the use of fluorochemicals in household cleaners (1
) and products applied to improve stain resistance (2
), and in some cases, municipalities treat landfill leachates that contain high levels of fluorochemicals (4
). Unfortunately, conventional biological/mechanical waste-water treatment has limited effectiveness in removing fluorochemicals from aqueous waste streams, and therefore, WWTPs are point sources for fluorochemicals that enter the environment (3
). Sinclair and Kannan attributed increases in perfluorocarboxylates in effluent to the degradation of precursor compounds during secondary treatment without significant removals (6
). A study of 10 WWTPs across the U.S. showed inconsistent removal of fluorochemicals even among plants with the same types of treatment processes, and in some cases, wastewater treatment resulted in the production of fluorochemicals (5
Relatively few studies have placed the discharge of fluorochemicals by WWTPs into a broader context. Boulanger et al. (7
) conducted a mass budget of perfluorooctane sulfonyl fluoride (POSF)-based fluorochemicals in Lake Ontario and estimated that the most significant inputs were inflows to the system from Lake Erie and WWTP effluents, while removal through sorption, volatilization, or degradation was determined not to be significant. Other studies traced unusually high levels of fluorochemicals to an upstream input, as in Skutlarek et al., where waste containing fluorochemicals was inadvertently land applied and the resulting runoff caused high levels of contamination in the local watershed (8
). A study of fluorochemicals in a North Carolina watershed suggested inputs from local sources, including fire-fighting foams used at military bases (9
). Surface and drinking waters in northern Italy also were analyzed for fluorochemical contamination; probable sources of fluorochemicals included urban and industrial wastewater inputs, while analysis of precipitation proved to be an additional input to this system (10
). The annual flux of perfluorocarboxylates (PFCAs) estimated from concentrations measured in 14 major European rivers was found to be the highest in watersheds that had known fluorochemical manufacturing facilities or large populations (11
). Recent papers suggest nonpoint sources including urban runoff waters as the sources of fluorochemicals to aqueous urban systems (12
). While the sources of fluorochemicals to watersheds have been implied, the quantitative contribution of wastewater effluent to the total loads of receiving waters has not been quantified.
The objective of the present study was to quantify fluorochemicals present in the aqueous phase in the Glatt River of Switzerland and to compute the contribution of WWTPs to the river’s mass flow. In the pursuit of this objective, the relative efficiency of seven WWTP’s removal of fluorochemicals was evaluated. The concentrations of four perfluoroalkyl sulfonates (C4–C8), five perfluoroalkyl carboxylates (C6–C10), one fluorotelomer sulfonate, and one perfluoroalkyl sulfonamide were measured in aqueous, 24 h, composite samples over a period of 1 week in WWTP effluents and in Glatt River water. From WWTP effluent concentrations and flow data, WWTP contributions to the Glatt River mass flows were computed and compared to the actual measured mass flows.