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(18-54) Short-term exposure of zebrafish to effluents from municipal sewage treatment works and pulp mills. Orn, Stefan*,1, Borg, Daniel1, Holbech, Henrik2, Norman, Anna1, Gessbo, Asa1, Norrgren, Leif1, 1 Department of Pathology, Fac Vet Med, Swedish University of Agricultural Sciences, Uppsala, Sweden2 Institute of Biology, South Danish University, Odense, Denmark ABSTRACT- In the present study, zebrafish (Danio rerio) were exposed to treated effluent water from one municipal sewage treatment works and two different pulp mills. The fish were exposed between 10-38 days post-hatch (dph). At 38 dph, zebrafish were sampled and analysed concerning vitellogenin concentrations in whole-body homogenates. At 60 dph, fish were sampled and examined by light microscopy, with focus on sex determination and gonad morphology, e.g. intersex. Exposure to effluent water from one of the pulp mills, resulted both in the induction of vitellogenin and in an increase in the number of males. Also, individuals with ovo-testis were found in all exposed groups. The present study shows that when exposing zebrafish to chemically complex effluents during gonad differentiation, both feminisation and masculinisation processes can be detected, when using endpoints including sex ratios and gonad morphology, as well as vitellogenin induction. Key words: zebrafish, endocrine disruption |
