Author Description

This document sets out an approach to human health risk assessment for priority substances under paragraph 11(c) of the Canadian Environmental Protection Act. It first briefly describes aspects considered in the evaluation of data relevant to assessment of "toxic" under paragraph 11(c). This is followed by description of the principles used in the assessment of exposure and the approach to evaluation of effects for different types of substances: non-threshold toxicants, threshold toxicants, possible threshold toxicants, and mixtures. Appendices include: reference values for assessing total daily intake of priority substances by the general population in Canada; criteria for classification of carcinogenicity & mutagenicity; definitions of terms; and reference values for intakes & body weights of laboratory animals.