Information in this book was obtained from individual experts and highly regarded sources. It is the publisher’s intent to print accurate and reliable information, and numerous references are cited; however, the authors, editors, and publisher can not be responsible for the validity of all information presented here or for the consequences of its use. Information contained herein does not necessarily reflect the policy or views of the Society of Environmental Toxicology and Chemistry. This book presents the proceedings of a SETAC Workshop convened by the Society of Environmental Toxicology and Chemistry (SETAC) and the European Union in Le Croisic, France, in October 2003. The 77 scientists involved in this workshop represented 17 countries from Europe, the United States and Canada and offered expertise in ecology, ecotoxicology, environmental regulation, and risk assessment.