Endocrine disrupting substances and ecological risk assessment of commercial chemicals in Canada

The ecological risk assessment of commercial chemicals in Canada by the reg ulatory programs of the Commercial Chemicals Evaluation Branch, Environment Canada, are based on results from traditional toxicity data (e.g., lethali ty, effects to growth or reproduction). Some of the chemicals under conside ration are known to alter endocrine systems in exposed organisms; however, effects to the endocrine system are used only as additional supporting info rmation. Presently, there are no internationally accepted methodologies or tests for endocrine disrupting substances that can be used by these regulat ory programs. The need for research with respect to hormone disrupting subs tances has been recognized in the revised Canadian Environmental Protection Act, 1999 (CEPA 1999). This paper describes the framework for the ecologic al risk assessment of new and existing substances and identifies issues and research needs in both screening level and in-depth ecological risk assess ments with respect to the identification and assessment of potentially endo crine disrupting substances.