Distribution, Source And Risk Assessment Of Typical Environmental Hormones In Sewage Treatment Plants In Hefei City

Endocrine-disrupting compounds(EDCs)are a class of organic substances that can affect the normal physiological activities of living organisms on earth even at low concentrations and interfere with the endocrine functioning of living organisms.Therefore,the pollution status of EDCs in the environment and their possible ecological or health hazards have received more and more attention in recent years.Wastewater treatment plants,as an important point source for the release of EDCs in the water environment,it is important to study the residual characteristics of EDCs in the effluent of WWTPs and sludge and their risk evaluation to understand the release characteristics of environmental hormone-based pollutants and their risk management to the environment and human body in China.In this study,four key urban wastewater treatment plants located in Hefei city were selected to study 18 typical EDCs in four categories: estrogens,phthalates,PAHs,and PCBs.Based on the concentration levels of EDCs in the effluent and sludge of the selected wastewater treatment plants,the study focused on analyzing the pollution status of EDCs in the effluent and sludge of wastewater treatment plants,assessing the ecological risk was evaluated and the possible human health hazards were assessed.The EPA PMF 5.0 software was also used to conduct source analysis of EDCs in the influent water of the wastewater treatment plant in order to identify the main sources of pollution according to the coexistence of various pollutants in urban wastewater.The main research contents and conclusions are as follows.(1)A total of 9 of 18 EDCs were detected in the effluent of all wastewater treatment plants,including 5 estrogenic substances and 4 phthalate esters.Among them,the detection rates of NP(Nonylphenol)and DEHP(Di-2-ethylhexyl phthalate)reached 100%,while the detection rates of BPA(Bisphenol A),DEP(Diethyl phthalate),DBP(Dibutyl phthalate),and DMP(Dimethyl phthalate)were in the range of 15%-95%,while the detection rates of E1(Estrone),E2(Estradiol),E3(Estriol)were less than 10%.A total of 9 of 18 EDCs were detected in the sludge,including 4 estrogenic substances,4 phthalates and 1 PAH,of which the detection rate of DEHP was 100%,and the detection rates of the remaining environmental hormones were below 85%.(2)The concentrations of estrogens ranged from ND(not detected)to 22.4 μg/L,phthalates ranged from ND to 74.54 μg/L,PAHs and PCBs were not detected,and total EDCs ranged from 1.02 μg/L to 75.27 μg/L in the effluent of all WWTPs.The total EDCs concentrations ranged from 1.02 μg/L to 75.27 μg/L.The overall level of EDCs was moderate to high at home and abroad.For the four seasons,the concentration of total EDCs in the effluent was higher in summer.In the sludge,the concentrations of estrogens ranged from ND-10.84 mg/kg,phthalates from ND-2165.75 mg/kg,PAHs from ND～0.26 mg/kg,PCBs from ND,and total EDCs from ND-2176.85 mg/kg.Again,the highest concentrations of total EDCs were found in the sludge in summer.The high concentrations of phthalates detected in the effluent and sludge in summer resulted in higher concentrations of total EDCs than in the other three seasons.(3)The concentrations of environmental hormone pollutants in the effluent and sludge of the four wastewater treatment plants showed seasonal changes,and the seasonal changes of pollutants in the effluent and sludge were characterized as follows: the concentrations of estrogen pollutants were higher in autumn than in the other three seasons;phthalate pollutants were higher in summer than in the other three seasons;and the concentrations of PAHs in sludge were higher in summer than in spring,but were not detected in the other two seasons;overall The concentration of pollutants in sludge was significantly higher in summer than in other seasons.The combined effects of influent concentration,different wastewater treatment processes,seasons,temperature,humidity,rainfall and other factors led to different seasonal distribution characteristics of different kinds of target pollutants.(4)From the perspective of spatial distribution,the content of estrogenic pollutants in the effluent of Tangxihe wastewater treatment plant was higher than that of the other three wastewater treatment plants,except for the content of estrogenic pollutants in the effluent of Tangxihe wastewater treatment plant.Both phthalate pollutants and polycyclic aromatic hydrocarbons pollutants were higher in the effluent and sludge of Wang Xiaoying wastewater treatment plant than in the other three wastewater treatment plants.(5)The ecological risk evaluation results show that the environmental hormone pollutants detectable in the effluent of the wastewater treatment plant will cause high ecological risk to the ecological environment of the Chaohu Lake water system,E1,E3 and DEHP are pollutants that produce high risk,and the pollutants in the sludge currently have low ecological risk;the human health risk evaluation results show that its cumulative risk index is greater than 1,and if the effluent is not strictly controlled but directly discharged into the water body,it will cause irreversible damage to human health in the long run.(6)According to the EPA PMF 5.0 software source analysis,the main sources of pollution in the service area of the wastewater treatment plant intake are industrial wastewater discharge sources and domestic sewage discharge sources,while the emission of traffic exhaust,filtrate from domestic garbage and solid waste piles,and pollution from agriculture,all of which contribute to the pollution of environmental hormone-like substances in the water environment.