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2L (1) - Immunotoxicity - genotoxicity - ED (WE8/6) Effects of treated sewage effluent on the immune and endocrine system of rainbow trout. Wasserrab, Birgit1, van den Heuvel, Mike2, Hitzfeld, Bettina3, Dietrich, Daniel1, 1 Environmental Toxicology, University of Konstanz, Germany, Konstanz, Baden-Württemberg, Germany2 Forest Research, New Zealand, Rotorua, Bay of Plenty, New Zealand3 Swiss Agency for the Environment, Forests and Landscape, Switzerland, Berne, Kanton Berne, Switzerland ABSTRACT- Possible detrimental effects of xenobiotics present in surface waters on fish populations can be due to alterations of the reproductive system as well as adverse effects on the immune system, the latter possibly leading to decreased resistence to fish-pathogens. In order to assess potential effects of the pollution of surface waters via treated sewage effluent (STW), rainbow trout (Oncorhynchus mykiss) were exposed to either 1.5 or 15% effluent for eight months (chronic exposure). After the exposure, growth and organ weights as well as EROD activity in liver, plasma vitellogenin levels and plasma steroid levels were investigated. Chronic exposure to 15% STW resulted in higher liver EROD activity in mature male trout, as well as in higher gonad and liver weights in mature males and females compared to control fish. Increased gonad weight in females was reflected in an increased egg count per body weight. Measurement of plasma steroids revealed increased 17 Key words: sewage treatment water, rainbow trout, immunotoxicity |
-estradiol levels in mature females exposed to 15% STW. Additionally to these parameters, the following immune parameters were investigated: head-kidney macrophage phagocytotic activity and oxidative burst, blood cell differentials and serum lysozyme activity. Moreover, effects on specific antibody production were investigated in fish injected with formalin-inactivated trout pathogen Aeromonas salmonicida during the exposure to STW.