Risk Assessment of Chemicals

Risk assessment of chemicals is a process that results in a quantitative and/or qualitative estimate of risk posed by chemical exposure. It includes identification of the hazard, a dose-response assessment, exposure assessment and risk characterization. The process of risk assessment continually evolves as science refines estimates of exposure and toxicity. There are two main types of risk assessment, human health and ecological, which have evolved separately to a large extent. Human health risk assessment is concerned with the protection of individuals. It considers hazard and risk to sensitive subpopulations, such as children and the elderly. Ecological risk assessment is concerned with protecting the environment and considers multiple species. Because the entity of concern is the ecosystem, the focus is on protection of populations rather than individuals. Both types of risk assessments typically utilize models to estimate the dose of chemical received and the likelihood that toxicity will occur in a particular exposure scenario. These models incorporate assumptions about exposure and toxicity, and must address both variability and uncertainty associated with risk estimates. Risk assessment is an important tool in managing potential public health and environmental impacts resulting from the use of chemicals. Keywords: risk assessment; hazard assessment; toxicity; uncertainty factors; dose-response relationship; deterministic risk; probabilistic risk; exposure; threshold dose; benchmark dose; ecological risk assessment