Contamination Characteristics And Ecological Risk Assessment Of PAEs And OPEs In Sediment In Taihu Lake Basin

Phthalic acid esters（PAEs）and organophosphate esters（OPEs）are two types of synthetic plastic additives which were used in kinds of commercial and industrial products.Numbers of researches have shown that PAEs and OPEs have endocrine disrupting effects,teratogenic,carcinogenic,mutagenic effects and other adverse effects,affecting the balance of the ecosystem and threatening human health.Therefore,pollution characteristic,migration-transformation and ecological risk in various environmental media have caused extensive attention.In this study,we analyzed surface sediments from rivers and lakes in Taihu Lake and Changzhou City,explored the pollution concentration,spatial distribution characteristics and sources of PAEs and OPEs.Besides,by analyzing two sediment cores from lake,we revealed the vertical distribution characteristics and pollution history in Taihu Lake.Ecological risks of PAEs and OPEs were assessed through Hazard Quotient（HQ）.The main results are as follows:（1）The ranges ofΣPAEs in surface sediment and sediment cores were 1117.40～18710.79 ng·g^-1 and 328.65～5218.82 ng·g^-1,respectively,ΣPAEs in sediment from lake were higher than those from rivers,ΣPAEs in sediment from Changzhou river were equivalent to the concentration of rivers entering the lake in the corresponding downstream area（Zhushan Bay）,and dibutyl phthalate（DBP）was dominant compounds,Overall,northern part of Taihu Lake has the highest concentration ofΣPAEs,followed by eastern and western parts,and southern part has the lowest degree of pollution,which is closely related to population of the corresponding area and development level of industrial enterprises.Vertical variation of PAEs was related to socio-economic development at different times.（2）Ranges ofΣOPEs in surface sediment and sediments cores were 22.65～326.84 ng·g^-1 and 30.09～332.32 ng·g^-1,respectively.Concentration of OPEs in lakes was higher than that of corresponding rivers,andΣPAEs in sediment from Changzhou river were equivalent to the concentration of rivers entering the lake in the corresponding downstream area（Zhushan Bay）.Tributyl phosphate（Tn BP）and tris（2-butoxyethyl）phosphate（TBEP）were the dominant compounds in Taihu Lake,and composition of OPEs between sediment from lake and sediment from rivers were similar,suggesting that river input may be a major source of OPEs in Lake.The pollution of OPEs in the northwestern part of Taihu Lake is more serious,which is corresponding to the large distribution of OPEs-related industrial in the region.Results of source apportionment indicated that sewage discharge,transportation discharge and atmospheric deposition were possible sources of OPEs in Taihu Lake.Composition of OPEs in the two sediment column samples vary with sampling locations,more types of OPEs in the northern core were detected.（3）Hazard Quotient（HQ）was used to evaluate the ecological risks of PAEs and OPEs in the Taihu Lake Basin,and prediction of no effect concentration（PNEC）of each target compound was obtained through Assessment Factor（AF）or Species Sensitivity Distribution（SSD）.As for ecological risk of PAEs evaluated by SSD,DBP posed medium or low ecological risk,while DEHP,DMP and DEP have no ecological risk.DIBP evaluated by AF posed high ecological risk in some sites,and posed medium ecological risk in most areas.For OPEs,no ecological risk was observed evaluated by SSD.Among the OPEs evaluated by AF,2-ethylhexyl diphenyl phosphate（EHDPP）posed highest ecological risk,and EHDPP and TBEP posed lower ecological risk in most areas.Sites with high risks and contaminants posed high risks require further attention.