Partitioning behavior, source identification, and risk assessment of perfluorinated compounds in an industry-influenced river

Abstract

BackgroundThe widespread application of perfluorinated compounds (PFCs) makes them ubiquitously distributed in the environment. Investigation of contamination profiles, distribution, possible sources and risks of PFCs in Liaohe River, an industry-influenced river in northeast China was conducted in the present study.ResultsThe total PFCs concentrations (∑PFCs) were in the range 0.38–127.88 ng/L (average value of 36.41 ng/L) in water and 1.72–10.44 ng/g dry weight (average of 4.99 ng/g) in sediment. Perfluorooctanoic acid (PFOA) was the dominant individual in water and sediment phases, in the range 0.38–73.94 ng/L in water and below detection limit (BDL) to 7.88 ng/g dw in the sediments. The organic carbon normalized partition coefficients (Koc) ranged from 2.46 L/kg (PFHxA) to 4.29 L/kg (PFUnDA). The average Koc values for perfluorocarboxylic acids (PFCAs) increased by 0.13–0.62 log unit with each increasing CF2 moiety, and the Koc values were lower than perfluoroalkyl sulfonates (PFASs). The sources of PFCs identified from diagnostic ratios suggested that the contaminants were mainly from the emission of manufacturing processes and precursors degradation. Result from risk assessment indicated that the immediate health impact through intaking water was negligible, but the levels of PFOA in surface water might cause effects on aquatic ecosystem. The mass inventories of ∑PFCs and PFOA were estimated to be 328.74 t and 103.43 t in the study area, respectively, suggesting that the sediment in Liaohe River may act as a potential PFCs source to the surrounding areas.ConclusionThis study demonstrated that PFCs were widely presented in the water and sediments of Liaohe River. In general, PFCAs had higher concentrations and detection frequency than PFSAs, and PFCAs with short carbon chains had much higher detection frequencies than long-carbon chain compounds in water. Among all PFC homologues, the average Koc increased with the increased carbon chain. Koc values were higher for PFSAs than PFCAs. The risk assessment suggested that PFOA in water may exert adverse effect on the aquatic ecosystem. Liaohe River was likely acting as a PFCs source to the surrounding area.