Trace Analysis Of Environmental Endocrine Disruptors And Its Application In Water Environment Monitoring

Environmental endocrine disruptors(EEDs)are ubiquitous in water environments.The endocrine and nervous systems of aquatic species could be adversely affected by the EEDs,even exposed at low concentration levels.Steroid estrogens(SEs),phenolic environmental estrogens(PEEs),and phthalic acid esters(PAEs)are three classes of typical EEDs with estrogenic activity.Their concentrations are mostly as low as ng/L to ug/L levels in water environments.Thus,it is difficult to effectively monitor these pollutants in environment samples,especially for wastewater samples of which the matrix is complex.Therefore,it is necessary to develop an analytical method with high sensitivity accuracy and precision to determine their concentrations from various water samples.Five SEs(estrone(E1),17?-estradiol(E2),estriol(E3),17?-ethinyl estradiol(EE2)and diethylstilbestrol(DES)),three PEEs(nonylphenol(NP),octylphenol(OP)and bisphenol A(BPA)),and six PAEs(dimethyl phthalate(DMP),diethyl phthalate(DEP),dibutyl phthalate(DBP),diethyl(2-ethylhexyl)phthalate(DEHP),butyl benzyl phthalate(BBP)and di-n-octyl phthalate(DNOP))are the target compounds in this study.A trace analytical method was developed to determine the concentrations of the typical EEDs in surface water and sewage based on fully automatic solid phase extraction(FASPE)and gas chromatography-mass spectrometry(GC-MS).The recoveries of the EEDs were in a range of 65-110% for all samples;the relative standard deviation were between 2% and 12%,and the method detection limits for the analytes were from 0.2 to 4.5 ng/L.The method was further applied to water environment monitoring,and the composition,pollution levels,spatio-temporal distribution and potential ecological risks of the EEDs were studied in different aquatic environments.It was found that:1.The EEDs were widely detected in river waters and municipal sewage,and the pollution was dominated by PEEs.NP,OP,BPA,E1 and E3 which were all detected two municipal sewage treatment plants,and the total EEDs concentration(?EEDs)ranges(mean value)in the influent and effluent were 4-201 ?g/L(4.5 ?g/L)and 80-1470 ng/L(720 ng/L),respectively.The removal rates of ?EEDs by A/A/O and oxidation ditch processes were94.2-99.8% and 79.7-98.9%,respectively.The removal rates of PEEs in the two wastewatertreatment plants(WWTP)were both above 85%.The average removal rates of E1 and E3 by A/A/O process were 48.7% and 20.1%,respectively.On the other hand,the SEs removal rate by oxidation ditch process was up to 94%.2.In the urban rivers of Guangzhou,the concentrations of SEs and PEEs ranged in nd(not detected)-69.5 ng/L(E1)and 2.3(OP)-41100 ng/L(NP),respectively,and the ?EEDs concentrations(mean value)were ranging in 0.31-42.8 ?g/ L(3.5 ?g/L).In the urban rivers of Chengdu,the concentrations of SEs,PEEs and PAEs ranged in <1.0(E2)-12.4 ng/L(E1),<1.2(OP)-1020(NP)ng/L,and 3.4(DEHP)-2060(DBP)ng/L,respectively,and the ?EEDs concentration range(mean value)was 0.09-3.6 ?g/L(0.94 ?g/L).The concentrations of?EEDs in the rivers of Guangzhou were significantly higher than those in Chengdu.The concentration levels of ?PEEs in Guangzhou urban rivers were 1-2 orders of magnitude higher than those in Chengdu,and their concentrations of SEs were at similar level.This might be related to the higher industrial development and population density of Guangzhou,where the manufactures and usage of PEEs were much higher than those of Chengdu.3.The concentrations(mean value)of ?EEDs in the Pearl River System were in a range of 0.03-5.8 ?g/L(1.52 ?g/L),and the pollution was mainly derived from OP,NP,BPA and E1.The concentrations of ?EEDs in Dongjiang River(DR),Guangzhou section of Pearl River(GPR)and Beijiang River(BR)were 0.8-5.8 ug/L(1.49 ug/L),0.4-2.8 ug/L(1.02 ug/L),and0.12-0.31 ug/L(0.19 ug/L),respectively.The concentration levels decreased in the order of DR > GPR > BR.Besides the ?EEDs concentrations were significantly higher in the wet season than those in the dry season.4.The concentrations of EEDs in the main stream of the Pearl River and the urban rivers of Guangzhou were correlated with the environmental parameters such as chlorophyll a,dissolved oxygen,conductivity and dissolved organic carbon.This suggested that the distribution and behavior of EEDs in aquatic environments might be affected or controlled by these environmental factors.3.According to a preliminary risk assessment,it was found that the Hazard index(HI)(mean value)of the EEDs in the influents and effluents from the sewage treatment plants were1.51-2.98(2.32)and 0.19-2.7(1.42),respectively,and the main contributions were from the high concentration of NP,BPA and high estrogenic activity of E1.The HI values of DR,GPRand BR were 0.48-14.2(3.64),0.87-7.1(2.78)and 0.28-0.87(0.4),respectively.The average risk quotient(RQ)of NP was 2.9,indicating that NP pollution was the main risk source of the basin.Similar phenomena were also found in the urban rivers of Guangzhou,where the HI of EEDs was in a range of 0.91-96(8.71),and high level of NP was also the main contributor to the ecological risk.The HI values of EEDs were in the urban rivers of Chengdu were between0.09 and 5.42(1.91),and the medium risk was mainly from OP,NP,E1 and E2.In summary,all the rivers WWTP effluents in this study were at a medium to high level of ecological risk,suggesting that a potential threat has been posed to the local aquatic organisms.