Distribution Characteristics Of Poly-and Perfluoroalkyl Substances In The Yangtze River Delta By Ultra Performance Liquid Chromatography-tandem Mass Spectrometry

The Yangtze River Delta is the largest economic zone,which is located in the eastern part of China.With the rapid development of economy,the major industry in the Yangtze River Delta has changed into the chemical engineering,textile and paper making.All of those factories have discharged a large amount of wastewater annually in the urban agglomerations of the Yangtze River Delta which contain a number of drinking water sources,making the problem of water pollution of this region becomes increasingly severe.With the development of economy and improvement of people’s living standards,the problem of drinking water safety is attracting more and more attention.Currently,the pollution of micro and trace organic pollutants in the water source has become the current concern.Meanwhile,Chemical engineering,textile and paper making industries are all major or potential sources of perfluorinated and polyfluorinated compounds.Therefore,this paper selected the Yangtze River Delta,Taihu Lake,Huangpu River,Qiantang River and Jiaxing urban river as the research areas in order to collect the surface water and sediment in different sites of the Yangtze River Delta.Besides,the pollution characteristics and risk analysis of polyfluorinated and perfluorinated compounds（PFASs）,such as Perfluoroalkyl carboxylic acids（PFCAs）,Perfluoroalkyl sulfonic acids（PFSAs）,Perfluoroalkyl phosphonic acids（PFPAs）,Perfluoroalkyl phosphinic acids（PFPiAs）and Polyfloroalkyl phosphoric acid diesters（diPAPs）were also studied.The method of SPE-UPLC-MS/MS（solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry）was build in this research to make the simultaneous extraction and analysis of 23 polyfluorinated and perfluorinated compounds in the surface water.Besides,the organic phase ratio of the eluent used in the process of solid-phase extraction,the content of ammonia in the solvent used in the process of activation and elution as well as the composition of the solvent analyzed by the extraction liquid machine were all optimized.Before instrumental analysis,the samples were divided into three parts:the first one is used for the analysis of PFCAs and PFSAs,here equal parts of ultrapure water were added to the extract;the second one is used to analyze PFPAs,in which equal parts of 25 mmol/L of tetra-butyl ammonium sulfate（TBAS）were added to the extract;the last one is made for the analysis of the PFPiAs and diPAPs,and the solution composition were methanol.The results showed the recoveries of target compounds were ranged from48.0%to 115.2%with relative standard deviation（RSD）was between 0.55%¹8.6%.Method detection limit（MDL）and method quantitative limit（MQL）were 0.003⁰.215 ng/L and0.01⁰.714 ng/L,respectively.This method is simple,high sensitivity and high precision which made it suitable for analyzing five kinds of perfluorinated and polyfluorinated from water simultaneously.The way of extracting PFASs from sediments was derived from the methods reported in literature.The recovery rate of the 23 PFASs in sediments ranged from 65%to 95%with the standard deviation（n=3）ranging from 3%to 13%,and the detection limit ranged from 0.02ng/g to 0.6 ng/g.Thus,this kind of method can achieve high recovery rate and high sensitivity,which is appropriate to do the extraction and detection of the 23 PFASs in sediments.Based on the established methods,the surface water and samples of sediment collected from the Yangtze River,Taihu Lake,Huangpu River,Qiantang River and Jiaxing urban river in April 2015 were processed and analyzed.The detection rates and concentrations of PFCAs and PFSAs in surface waters were much higher than those detected in sediments.The average concentrations of PFCAs and PFSAs in the study areas decreased in the following order:Yangtze Rive（191 ng/L）≈Taihu Lake（189 ng/L）>Huangpu River（122 ng/L）≈Qiantang River（120 ng/L）>Jiaxing Urban River（100 ng/L）.The Yangtze river,Jiaxing urban river and Taihu lake,the perfluoropentanoate（PFPeA）was the dominant congener,while the PFOS was predominant in the Huangpu and Qiantang rivers.Using Statistical Product and Service Solutions（SPSS）13.0 software for factor analysis and hierarchical cluster analysis,a significant correlation（p<0.05）was found among many compounds when analyzing all the compounds that were detected in the sampling areas,which suggested that those compounds sharing a common source.Only PFOA was detected in all sediment samples,with its concentrations ranging from 0.02 ng/g to 1.35 ng/g.It was also observed that there was a positive correlation between the logK_occ of PFOA and the TOC in sediments in the Jiaxing urban river.Although the main detected substances in the study areas differed,the total amount of PFCAs detected exceeded the total amount of PFASs by 66%.DiPAPs were detected in only 17 samples from all the Yangtze River Delta samples containing surface water and sediment.The concentrations of 6:2diPAP and 8:2diPAP in surface water samples ranged from 0.044 ng/L to 0.183 ng/L and 0.041 ng/L⁰.496 ng/L respectively,while the concentrations of the two substances in the sediment ranged from 0.235 ng/g to 4.05 ng/g and0.088 ng/g to 1.44 ng/g,respectively.In samples with diPAPs detected,the levels of 8:2di PAP were both higher than 6:2diPAP.PFPAs and PFPiAs were not detected in surface water and sediment samples.In this paper,the risk assessment of PFASs in the surface water of the Yangtze River Delta region was conducted.The risk levels of PFOA and PFOS were evaluated using the trade-in value method and the US EPA non-carcinogenic health risk model.It was concluded that the PFOA and PFOS in the Yangtze River Delta region were at a low risk level.However,the persistence and bioaccumulation of PFASs posed a potential threat to human and biological health.In the present study,the short-chain pollution of PFCAs and PFSAs was more common and serious,and its risk assessment on human beings and organisms should be further studied.In summary,the method of SPE-UPLC-MS/MS was established and the levels of PFCAs,PFSAs,PFPAs,PFPiAs and diPAPs in drinking water sources of major urban agglomerations in China were studied.Provide some technical help in studying the harm of PFASs to the ecological environment and human health,as well as the data for the pollution of PFASs in the Yangtze River Delta.