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(18-51) Vitellogenin induction in male zebrafish as a biomarker for the estrogenicity of sewage effluents. Duis, Karen*,1, Holbech, Henrik2, Bjerregaard, Poul2, Spengler, Peter3, Ternes, Thomas4, Knacker, Thomas1, 1 ECT Oekotoxikologie GmbH, Floersheim/Main, Germany2 Institute of Biology, Odense M, Denmark3 Institute of Sanitary Engineering, Water Quality and Solid Waste Management, Stuttgart, Germany4 ESWE-Institute for Water Research and Water Technology, Wiesbaden, Germany ABSTRACT- A test protocol with zebrafish (Danio rerio) was established in order to screen effluents from sewage treatment plants for their estrogenic potency. After exposure under flow-through conditions vitellogenin (Vtg) levels in whole body homogenate of male zebrafish were quantified using a direct non-competitive sandwich ELISA. Following solid phase extraction, clean-up and derivatisation, estrogenic compounds in the exposure water were determined either by GC/MS/MS (ethynylestradiol [EE2], first experiment) or by GC/MS (subsequent experiments). In the latter case, identification and quantification were carried out by using different analyte-specific internal standards with the standard addition method. Zebrafish were exposed for 10 days to EE2. In a first experiment, a 13,000-90,000fold increase in Vtg concentrations in comparison to the control was recorded at measured concentrations of 1.3-6.9 ng EE2/l. In a second experiment, a mean measured concentration of 1.1 ng EE2/l induced a 100fold increase in the Vtg level, while measured concentrations of 0.8 ng EE2/l and below did not lead to a significant increase in Vtg. Zebrafish were then exposed on site to final effluent from a municipal sewage treatment plant. Control fish were kept in reconstituted water. After 10 and 20 days of exposure, fish were sampled for measurement of Vtg. There was no marked induction of Vtg in zebrafish exposed to the sewage effluent. In subsequent experiments, the estrogenic potency of further compounds and another sewage treatment plant will be investigated. Key words: endocrine disruption, zebrafish, sewage effluent, vitellogenin |
