Pollution Characteristics And Risk Assessment Of Typical Emerging Contaminants In Drains Flowing Into The Yellow River Of Ningxia

Endocrine disrupting chemicals(EDCs)and pharmaceuticals and personal care products(PPCPs)are emerging contaminants causing potential threats on aquatic living organisms and human health.As an important part of surface water environment in Ningxia area,the quality of water in drains flowing into the Yellow River of Ningxia directly affect the water quality of Ningxia section of Yellow River.Solid-phase extraction and ultra-high performance liquid chromatography-mass spectrometry were used to detect and analyze the contamination of 9 EDCs and 23 PPCPs in drains flowing into the Yellow River of Ningxia,sources of these EDCs and PPCPs were analyzed,and their risks were assessed,in order to provide basic data and scientific basis for the pilot demonstration area of the Yellow River Basin’s ecological protection and high-quality development.The study showed that:(1)EDCs were detected in the drains with concentrations in the range from ND to 1367.41 ng·L-1 in winter and from ND to 964.82 ng·L-1 in summer.The EDCs with the highest detection rates in different seasons were bisphenol A(BPA,detection rate 97%)and estriol(E3,detection rate 67%),respectively.In terms of spatial distribution,EDCs in the drains with average concentrations of ∑EDCs showed that in the order Shizuishan>Yinchuan>Wuzhong>Zhongwei in both seasons.The total concentration of EDCs before flowing into the Yellow River ranged from ND to 1060.23 ng·L-1.In terms of seasonal distribution,most EDCs were detected at higher concentrations in summer than winter.The detection rate was higher in winter than summer.The main contaminants in winter were 17-βestradiol(E2)and octylphenol(OP),the main contaminants in summer were 17-aethynylestradiol(EE2),BPA and bisphenol F(BPF).Source analysis showed that BPA,BPF,nonylphenol(NP)and EE2 were more significantly correlated with total nitrogen(TN)or total phosphorus(TP),BPF was correlated with chemical oxygen demand(COD).Industrial wastewater and domestic wastewater were the source for BPA,whereas industrial wastewater was the primary source for OP.The primary sources of estrogenic compounds were livestock breeding wastewater and domestic wastewater.(2)Antibiotics were detected in the drains with concentrations in the range from ND to 437.31 ng·L-1 in winter and from ND to 473.07 ng·L-1 in summer.The antibiotics with the highest detection rates in winter were sulfadiazine(SDZ,detection rate 61%)and levofloxacin(LVX,detection rate 61%),with the highest detection rates in summer was ciprofloxacin(CIP,detection rate 82%).In terms of spatial distribution,antibiotics in the drains with average concentrations of ∑antibiotics showed that Yinchuan and Wuzhong were larger than Zhongwei and Shizuishan in both seasons.The total concentration of antibiotics before flowing into the Yellow River ranged from ND to 194.19 ng·L-1.In terms of seasonal distribution,most antibiotics were detected at higher concentrations in winter than summer;SDZ,clarithromycin(CLA),erythromycin(ETM)and lincomycin(LIN)were detected at higher rates in winter than summer,the detection rates of other antibiotics in winter were less than or equal to summer.The main contaminants in both seasons were quinolone antibiotics.Source analysis showed that SMZ,CLA and LVX were more significantly correlated with TN or TP,SMZ was correlated with COD).Livestock and poultry breeding wastewater were the source for SDZ and OTC,medical wastewater was mainly the source for LVX and CIP,pharmaceutical industrial production wastewater was the source for LIN.(3)Other PPCPs were detected in the drains,with concentrations in the range from ND to 1170.61 ng·L-1 in winter and from ND to 563.23 ng·L-1 in summer.Avobenzone(BM-DBM)and benzophenone-3(BP-3)were detectable at all sampling sites in winter.The other PPCPs with the highest detection rates in summer were BP-3(detection rate 91%)and mosquito-repellentamine(DEET,detection rate 91%).In terms of spatial distribution,other PPCPs in the drains with average concentrations of ∑other PPCPs showed that Shizuishan and Yinchuan were larger than Wuzhong and Zhongwei in both seasons.The total concentration of other PPCPs before flowing into the Yellow River ranged from 80.11 to 1010.63 ng·L-1.In terms of seasonal distribution,the contamination level of pharmaceutical compounds in winter were higher than summer,but personal care products in summer were higher than winter,the detection rate of most other PPCPs in winter were higher than summer.The main contaminants in winter were anti-inflammatory drugs and stimulants,while the main contaminants in summer were UV sunscreens and insect repellents.Source analysis showed that diclofenac(DIC),ibuprofen(IBU),carbamazepine(CBZ),caffeine(CAF),BM-DBM,triclocarban(TCC),and DEET were more significantly correlated with total TN or TP.CAF,DEET,and BM-DBM were correlated with COD.Domestic wastewater was the source for DIC,CAF,BP-3,and 4-methylbenzylidene camphor(4-MBC),domestic wastewater and industrial wastewater were the source for TCC and triclosan(TCS),domestic wastewater and receding water from agricultural fields were the source for DEET.(4)The ecological risk assessment indicated that among the EDCs,BPS posed high risk,and NP,OP,E2 and EE2 posed medium risks.In winter,the mixture risk of EDCs which exhibited low or medium risk at most sampling sites.In summer,the mixture risk of EDCs which exhibited medium or high risk at nearly more than half of the sampling sites.Most of the sampling sites in the study area,EDCs showed high risk for estrogenic activity.Among antibiotics,LVX posed high risk,CLA and ETM posed medium risks.The mixture risk of antibiotics which exhibited medium or low ecological risk at most sampling sites in both seasons.Among the 14 other PPCPs,DIC,GEM,IBU,CBZ,BP-3,TCC,and TCS posed high risks,and APAP,BF,BM-DBM,and 4-MBC posed medium risks.The mixture risk of other PPCPs which exhibited high risk at most sampling sites in both seasons.