title: Biomarker responses and reproductive toxicity of the effluent from a Chinese large sewage treatment plant in Japanese medaka (Oryzias latipes).
abstract: The present study was conducted to assess the potential toxicity of the effluent from a large sewage treatment plant (GBD-STP) in Beijing. Japanese medakas (Oryzias latipes) at reproduction active period were exposed to a serial of graded concentrations of the effluent or 100 ng l-1 of 17-alpha-ethinylestradiol (EE2, positive control). Growth, gonadosomatic index (GSI), hepatosomatic index (HSI), reproductive success, induction potency of vitellogenin (VTG) in male fish and that of 7-ethoxyresorufin-o-deethylase activity (EROD) in male fish liver were used as test endpoints. The growth suppression of fish was observed in a dose-dependent manner, resulting in significant differences in both body length and body weight of medaka above 5% effluent. This effluent can inhibit the growth of gonad of medakas and are more sensitive to male than to female. At exposure concentration of 40% and higher, there was an unexpected decrease of HSI values, which may be resulted from sub-lethal toxicity of effluent to fish liver. VTG of plasma in males were induced in all exposure concentration levels, but not in a dose-dependent manner. The concentration of 5% effluent would be the lowest observed adverse effect level (LOAEL) affecting reproductive success when examining fertile individuals, fecundity and fertilization rate. The overt CYP1A response and higher reproductive toxicity may be indicative of low process efficiency of this STP.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, PR China. mtw922@163.com
authors.forename: Taowu
authors.initials: T
authors.lastname: Ma
authors.forename: Xiaoqiong
authors.initials: X
authors.lastname: Wan
authors.forename: Qinghui
authors.initials: Q
authors.lastname: Huang
authors.forename: Zijian
authors.initials: Z
authors.lastname: Wang
authors.forename: Jiankang
authors.initials: J
authors.lastname: Liu
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002681:China; D002947:Cities; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D023381:Endpoint Determination; D005260:Female; D006066:Gonads / Q000187:drug effects; D008099:Liver / Q000187:drug effects; D008297:Male; D008826:Microbial Sensitivity Tests; D009990:Oryzias / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D012098:Reproduction / Q000187:drug effects* / Q000502:physiology; D012722:Sewage; D012737:Sex Factors; D014819:Vitellogenins / Q000378:metabolism; D014865:Waste Disposal, Fluid; D014873:Water Pollutants / Q000633:toxicity*
chemical_list: D012722:Sewage; D014819:Vitellogenins; D014873:Water Pollutants; D019363:Cytochrome P-450 CYP1A1