ABSTRACT
There is increasing awareness over the adverse effects of environmental contaminants on the health and well being of both humans and wildlife (Olsson et al., 1998; Tyler et al., 1998). While evidence for humans is still somewhat circumstantial, the occurrence of a variety of developmental and reproductive disorders in wildlife species have clearly been linked to the exposure to environmental contaminants. Due, in part, to the fact that most man-made contaminants will eventually end up in the aquatic environment, most of the more pronounced developmental and reproductive disorders have been reported in aquatic species. For example, probably the most clearly identified case of endocrine disruption to date is that of imposex (development of a penis and vas deferens in females) in marine gastropods, resulting from the exposure to tributyltin
(Gibbs et al., 1990). Another widely documented example of endocrine disruption in aquatic species is that of feminization of male freshwater fish (Jobling et al., 1998). In this case, as a result of exposure to primarily domestic effluents, male fish show elevated plasma levels of the femalespecific yolk protein precursor, vitellogenin (VTG), as well as a high incidence of intersex (ovo-testis).
