Endocrine modulators: risk characterization and assessment.

Over the last several years, information has been accumulating that suggests that adverse effects are being induced in certain wildlife species, and perhaps also in humans, as a consequence of exposure to man-made chemicals that have been released into the environment. Many of these effects have been attributed to interactions with various hormone systems in endocrine tissues. Most often the effects observed have been effects on reproduction and development, although there are also (often conflicting) data regarding an association between exposure and certain kinds of cancer, particularly cancers of reproductive tissues such as breast and testis; effects on the immune system have also been noted. The substances to which these attributes have been ascribed have come to be known as "endocrine modulators" or "endocrine disruptors." The full nature and scope of the "problem" of endocrine modulators/disruptors is currently a matter of great debate, both within and outside of the scientific community. Regulatory authorities around the world are being asked what their position is on this issue and what, if any, regulatory strategies they are developing to address the problem. In many cases, because of the nature of the legislation under which governments manage chemicals, regulatory decisions must be informed by risk assessment. This presentation will describe the general approach to the risk assessment of endocrine modulators/disruptors as practiced by the US government, with particular focus on the current practices/policies of the US Environmental Protection Agency.