Pollution Characteristics And Ecological Risk Assessment Of PAEs In Xi'an Section Of The Weihe River Basin

Phthalate acid esters(PAEs)are a kind of endocrine disrupting chemicals and common contaminant in river,which are widely used in plastics,paints,and personal care.PAEs have been driving widespread attention of human,because their effects are similar to estrogen and toxicity such as carcinogenic and teratogenic.In this study,four tributaries(Fenghe River,Zaohe River,Bahe River,Jinghe River)and main stream of Weihe River in Xi'an section are taken as the research area.Four kinds of PAEs: dimethyl phthalate(DMP),diethyl phthalate(DEP),butyl benzyl phthalate(BBP)and dibutyl phthalate(DBP)were studied.The research analyzed temporal and spatial distribution characteristics of four PAEs in Xi'an section of Weihe River and assessed their the ecological risk in water by Species Sensitivity distributions(SSD).The results provided the basic theory for the pollution and ecological management of PAEs in the Weihe River.The main findings were as follows:(1)The concentrations of PAEs in the water of the Fenghe River,Zaohe River,Bahe River,Jinghe River and Weihe River were 6.43~24.82 ?g/L,12.95~103.56 ?g/L,ND~88.0 ?g/L,6.34~110.76 ?g/L and 4.83 ~ 77.32 ?g/L respectively.DMP and DBP were the main pollutants in the water of the Weihe River in Xi'an section.Compared with the content of PAEs in surface waters of domestic and international research,the concentration of PAEs in Xi'an section of the Weihe River was at a high level.(2)The spatial distribution characteristics of PAEs in the four tributaries and the main stream of the Weihe River in Xi'an section had some differences in the three periods of dry,flat and wet season.In the dry season,they were characterized by Zaohe River > Jinghe River > Weihe River > Fenghe River > Bahe River,the fiat season is the Jinghe River > Zaohe River> Weihe River > Bahe River > Fenghe River.During the wet season,it showed the space of the Bahe River > Zaohe River > Weihe River > Jinghe River > Fenghe River.Zaohe River is the main polluted river in Xi'an City,Jingwei Industrial Park are on both sides of Jinghe River with fixed pollution sources,so the PAEs content in the water is high in dry and flat periods.The runoff of Bahe River was large in flood period and brought a lot of pollutants from erosion upstream and living areas of both sides by rainwater,which lead to the highest content of PAEs in the water of Bahe River in wet season.(3)The total concentration of PAEs of Weihe River in Xi'an section respectively was 5.5~54.55 ug/L,13.26~69.73 ug/L and 12.22~66.47 ug/L in dry,flat and wet season,and the average values were 31.34 ug/L,35.26 ug/L and 38.85 ug/L.With the seasonal variation,the temporal distribution pattern of PAEs showed wet season > fiat season > dry season.DMP and DBP accounted for 41.68% and 39.72% of PAEs,respectively.The content of DBP decreased from 49.76% in dry season to 32.86% in wet season,and proportion of DEP increased with time.(4)The ecological risk of the four PAEs was assessed by the fitted SSD curve.which the 5% as a threshold.The results showed that the comprehensive risk of the four PAEs in the main and tributaries of the Weihe was Jinghe River > Zaohe River > Weihe River > Bahe River > Fenghe River,and the ecological risk in different seasons showed that dry season > flat season > wet season.DBP has ecological risk in Zaohe River and Jinghe River,and potential ecological risk exists in Bahe River.DMP,DEP and BBP have no ecological risk in Weihe Basin.