An overview of substances present in Canadian aquatic environments associated with endocrine disruption

Numerous environmental contaminants have been associated with the ability t o affect the endocrine status of animals and with the potential to elicit e ffects on individuals or populations in Canadian aquatic environments. Pote ntial endocrine disrupting substances (EDS) consist of almost every class o f environmental contaminants reported to date, including industrial chemica ls, historical and current use pesticides, metals, and different classes of natural products. It has been difficult to establish cause-and-effect rela tionships with potential EDS for several reasons: i) the diversity of ways that chemicals can influence endocrine systems challenges efforts to charac terize chemicals that can cause endocrine responses, ii) many responses in aquatic biota have been associated with complex mixtures where the causativ e agents remain unidentified, and iii) most literature information deals wi th mammalian studies using pure compounds so there is considerable uncertai nty regarding extrapolation to aquatic species and efficacy of environmenta l concentrations. An overview of the literature on EDS, specific to exposur e within Canadian aquatic environments, is presented to emphasize the diver sity and complexity of chemicals capable of altering endocrine function.