Analysis Of The Distribution Of Typical Persistent Organic Pollutants In Weihe River Basin And Its Degradation Characteristics

Phthalates(PAEs)and polycyclic aromatic hydrocarbons(PAHs)are the two most common types of persistent organic pollutants in the water environment.Among them,PAEs are a class of endocrine disruptors with reproductive toxicity and growth and development toxicity.PAHs are easy to accumulate in living organisms and have strong carcinogenicity,teratogenicity and mutagenicity.Given that PAEs and PAHs are extremely harmful to human health,many countries have listed these two types of substances on the list of priority pollutants for environmental control.This study first investigated the pollution status of PAEs and PAHs in the water bodies of the Xi'an and Xianyang sections of the Weihe River Basin,and then studied the degradation characteristics of PAEs and PAHs in a wastewater treatment plant that enters the Weihe River and the concentration in the effluent.The traceability of PAEs and PAHs in saline waters provides a theoretical basis.The main research results are as follows:(1)An analytical method for the determination of phthalates(PAEs)and polycyclic aromatic hydrocarbons(PAHs)in water by solid phase extraction-gas chromatography / mass spectrometry(GC-MS / MS)was first established..In this method,the average spike recovery of PAEs in water samples is 74.2-85.4%,and the average spike recovery of PAEs in mud samples is 69.5-82.1%.The detection limit of PAEs is 0.75 ~ 1.68?g / L,and the limit of quantification is 2.26.~ 5.04?g / L,intraday standard deviation is 2.08 ~ 5.35%,intraday standard deviation is 4.01 ~ 6.24%;detection limit of PAHs is 0.39 ~ 1.67%,limit of quantitation is 1.17 ~ 5.00?g / L,intraday standard deviation is 1.24 ~ 5.30%,the day standard deviation is 1.28 ~ 9.16%.(2)Taking PAEs and PAHs as research objects,the gas chromatography-triple quadrupole mass spectrometry(GC-MS / MS)was used to detect the existing concentrations of 16 sampling points in the Xixian section of Weihe River.The results showed that the concentration of ?PAEs in Luanhe,Zaohe,and Luanhe rivers receiving the tail water of the sewage plant was 4006.71 ~ 4334.45 ng / L,and the concentration of ?PAHs was 402.66 ~ 892.15 ng / L.The ?PAEs concentration in the dry season was 13338.25 ~ 13753.83 ng / L The ?PAHs concentration was 161.75-184.21 ng / L.Yangling,Qishuihe,Heihe,Xingping,Luohe,Xinhe,Xianyang Tieqiao,Nanying,Tianjiang Rendu,Luanhe,Gengzhen Bridge,Linhe and Xinfeng River without receiving the tail water of the sewage plant The concentration of ?PAEs was 4134.70 ~ 34192.79 ng / L,and the concentration of ?PAHs was 379.00 ~ 2146.19 ng / L.In the dry season,the concentration of ?PAEs was 13146.60 ~ 40600.52 ng / L,and the concentration of ?PAHs was 100.52 ~ 699.63 ng / L.The above results indicate that the concentrations of PAEs and PAHs in Luanhe,Zahe,and Luanhe rivers receiving the tailwater of the sewage treatment plant are at relatively low levels,indicating that the sewage treatment plant has a significant reduction effect on PAEs and PAHs.(3)The PAEs and PAHs concentrations in the water phase and mud phase of Beishiqiao Sewage Treatment Plant and DE oxidation ditch during one cycle were detected.The results showed that five PAEs and six PAHs can be detected in the sewage water,the degradation of PAEs and PAHs were mainly performed in Bio-Denipho process-an anaerobic selector and a two-channel ditch.In the anaerobic selector,the removal efficiencies of Phthalates were DEHA(33.6%)> DEHP(33.1%)> DEP(25.7%)> DBP(24.6%)>DMP(17.5%),and the removal efficiencies of Polycyclic Aromatic Hydrocarbons were Chr(35.9%)> Pyr(35.0%)> Flu(32.7%)> Phe(30.3%)> Ant(28.0%)> Nap(27.3%),respectively,mainly caused by dilution and adsorption of the recycling sludge came from the final sedimentation tank.And in the following Bio-Denipho oxidation ditch treatment,the removal efficiencies of Phthalates were DEP(89.3%)> DMP(86.4%)> DBP(58.0%)> DEHP(29.4%)>DEHA(29.0%),and the removal efficiencies of Polycyclic Aromatic Hydrocarbons were Nap(68.75%)> Ant(58.33%)> Flu(48.57%)>Phe(45.65%)>Pyr(12.31%)>Chr(8.54%).The effluent PAEs concentration was 49.05 ~ 4575.06 ng / L,the removal rate was 47.44 ~ 92.00%;PAHs concentration was 4.25 ~ 165.25 ng / L,the removal rate was 42.97 ~ 76.93%,so the point source pollution of the sewage plant is not the main pollution source of the Weihe River.