SHORT-TERM TOXICITY OF BIS(TRI-N-BUTYLTIN)OXIDE IN FLOUNDER (PLATICHTHYS-FLESUS) - PATHOLOGY AND IMMUNE FUNCTION

The present study is part of a project that focuses on the relationshi p between environmental pollution and fish diseases. Field studies in various polluted coastal areas in Europe and the United States of Amer ica clearly indicate a relationship between pollution and the increase in prevalence of tumours and infectious diseases in fish. Research un der controlled laboratory conditions is necessary to prove causal link s between specific xenobiotics and disease prevalence. One of the chem icals of interest in the myriad of xenobiotics found in polluted water s and sediments is the organotin compound tributyltin (TBT), originati ng mainly from antifouling paints used on the hulls of ships. This rep ort describes a study in which flounders (Platichthys flesus) were exp osed to bis(tri-n-butyltin)oxide (TBTO) in the water under controlled laboratory conditions. The effects on several organs (gills, skin, eye , liver, mesonephros, ovary/testis, spleen, and gastrointestinal tract ) were examined using histopathology, and morphometric analysis of the thymus was performed to assess the target organ(s) for TBTO in this f ish species. Also the function of the non-specific and specific resist ance was studied using ex vivo/in vitro immune function tests. Exposur e of flounder to TBTO, in concentrations which were in the same order of magnitude as maximum TBT levels measured in the field (experiment: 17.3 mu g TBT/l; field: 7.2 mu g TBT/l), caused mortality after 7-12 d ays, resulted in gill lesions, and induced significant reduction of th e non-specific resistance. A significant decrease of the relative thym us volume, but no marked effects on the specific immune system were no ted after exposure to TBTO. (C) 1998 Published by Elsevier Science B.V . All rights reserved.