Determining indicators of exposure and effects for endocrine disrupting chemicals (EDCs): An introduction

Endocrine disruptors are characterized by their influence on animal endocri ne systems resulting in reproductive, developmental, neurological, and immu ne dysfunction. The purpose of this overview is to provide the reader with a sense of the activities within the U.S. Environmental Protection Agency ( USEPA), in particular NHEERL, that address the many facets of research on e ndocrine disrupting chemicals (EDCs) and to highlight the approach being ta ken at the different organizational levels within the USEPA, including scre ening, testing and evaluating endocrine disrupting chemicals. As a part of this endeavor, the USEPA continues to evaluate the current research activit ies in order to better understand and refine the process of risk characteri zation of EDCs. Thus, the participants in this session were asked to review their research within the framework of a better identification of EDC effe cts, better characterization of those compounds that have endocrine disrupt ing activity and how to incorporate this information into the risk assessme nt paradigm. Specifically, the goals of the ensuing papers were to compare individual vs. population indicators of endocrine disrupting effects, exami ne comparable and multiple mechanisms of toxicity, and describe the use of effects as indicators to identify toxicants and their sources. Mammalian an d fish reproductive endpoints. served as models to emphasize commonalities between human and wildlife risks.