|
(18-06) Estrogenicity of effluent from a Swedish sewage treatment works, before and after extended biological treatment. Norman, Anna*,1, Orn, Stefan1, Parkkonen, Jari2, Forlin, Lars2, Norrgren, Leif1, 1 Department of Pathology, Swedish University of Agricultural Sciences, Uppsala, Sweden2 Department of Zoophysiology, Göteborg University, Göteborg, Sweden ABSTRACT- In the present study, vitellogenin (VTG) concentrations were measured in plasma from juvenile rainbow trout (Oncorhynchus mykiss) exposed to effluent water from a municipal sewage treatment works in Uppsala, Sweden, before and after expansion of the biological treatment process. In the first study, conducted in 1998 before the enlargement of the plant, high levels (3 mg/ml) of VTG were detected in rainbow trout exposed at a constant flow to undiluted effluent. However, rainbow trout placed in cages downstream of the outlet showed no elevated VTG concentrations. During 1999, the biological treatment process at the plant was extended and modified to enhance the reduction of nitrogen. As a result, the retention time of the water increased and the amount of organic matter, nitrogen as well as ammonium-nitrogen in the effluent water decreased. In a second similar study, performed after the expansion of the plant, rainbow trout exposed to undiluted effluent showed no elevated VTG concentrations. In conclusion, the present study shows that the extended biological treatment was of primary importance in reducing estrogenic substances in the effluent water. Key words: rainbow trout, estrogenic, sewage treatment works, vitellogenin |
