title: [Toxicity evaluation on the effluent water from a sewage treatment plant in Zhengzhou City].
abstract: OBJECTIVE
  To explore the acute toxicity and genotoxicity of inlet and outlet water of a sewage treatment plant in Zhengzhou to provide scientific basis for the safety of sewage reuse.
  
  
  METHODS
  Inlet water, secondary and tertiary processed outlet water were collected from the sewage treatment plant. Acute toxicity and genotoxicity of the inlet and outlet water were detected by luminescent bacteria toxicity test and Vicia faba root tip cell micronucleus test, respectively.
  
  
  RESULTS
  The luminosity inhibition rates of luminescent bacteria by inlet water, secondary and tertiary processed outlet water were (33.96 +/- 7.51)%, (14.32 +/- 7.36)% and (7.24 +/- 5.58)%, and the micronucleus rates were (12.67 +/- 2.08) per thousand, (6.33 +/- 1.53) per thousand and (2.67 +/- 0.58) per thousand, respectively. The pollution levels of these three samples were heavy, mild and scarce, respectively. The inhibition rates of luminescent bacteria by the secondary and tertiary processed water were significantly lower than that of inlet water (F = 12.159, P = 0.008). A similar result was observed for micronucleus rate (F = 56.850, P < 0.001).
  
  
  CONCLUSIONS
  The acute toxicity and genotoxicity of processed water were decreased greatly. However, some potential ecological risks of the processed water still existed for environment.
authors.affiliation: Department of Environment Health, College of Public Health, Zhengzhou University, Zhengzhou 450001, China. fxygood6@163.com
authors.forename: Yajing
authors.initials: Y
authors.lastname: Feng
authors.forename: Bo
authors.initials: B
authors.lastname: Li
authors.forename: Xinjiong
authors.initials: X
authors.lastname: Guo
authors.forename: Liju
authors.initials: L
authors.lastname: Duan
authors.forename: Jun
authors.initials: J
authors.lastname: Cao
authors.forename: Sulan
authors.initials: S
authors.lastname: Wang
authors.forename: Xuemin
authors.initials: X
authors.lastname: Cheng
authors.forename: Chuanhong
authors.initials: C
authors.lastname: Xing
authors.forename: Liuxin
authors.initials: L
authors.lastname: Cui
mesh_terms: D001419:Bacteria / Q000378:metabolism; D002681:China; D002947:Cities; D008163:Luminescent Measurements; D015162:Micronucleus Tests / Q000379:methods*; D009153:Mutagens / Q000633:toxicity*; D018517:Plant Roots; D012722:Sewage; D023382:Toxicity Tests, Acute; D031307:Vicia faba / Q000187:drug effects / Q000235:genetics; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D009153:Mutagens; D012722:Sewage; D014874:Water Pollutants, Chemical