Occurrence and discharge of fluorotelomer carboxylic acids(FTCAs)in typical municipal WWTPs in China
Fluorotelomer carboxylic acids(FTCAs)are the precursors and substitutes of perfluoroalkyl carboxylates(PFCAs).In this study,the distribution and discharge characteristics of six FTCAs and twelve PFCAs in influent,secondary effluent,tertiary effluent and sludge samples from nine municipal wastewater treatment plants(WWTPs)in five cities in China were investigated by using the detection and analysis method of solid-phase extraction and liquid chromatography coupled with triple quadrupole mass spectrometry.The total concentrations of FTCAs in the influent from nine municipal WWTPs were 0.52-2.00×103 ng·L-1.The concentrations of FTCAs in the influent from municipal WWTPs receiving industrial wastewater were higher than those from other WWTPs mainly receiving domestic sewage,suggesting the influence of industrial wastewater on the concentration level of FTCAs.The removal efficiencies of FTCAs and PFCAs during biological treatment were 43%—93%and-40%—69%,respectively.The total discharge of FTCAs in the tertiary effluent and sludge was 13.6 g·d-1,6:2 FTCA and 8:2 FTCA as the predominant components.The risk quotient analysis of FTCAs and PFCAs in the tertiary effluent suggested that 6:2 FTCA,PFHxA,PFOA,PFNA and PFDA in the tertiary effluent may pose potential risks to fish in aquatic environment.This study provides the data basis for the management and control of emerging contaminants in municipal WWTPs in China.