ABSTRACT
This chapter provides an overview of environmental health risk assessment and to define what lessons can be gained from this strategy and transferred to the field of ecological risk assessment. The end-product of a risk-based approach to environmental management is either to identify an acceptable level of exposure or prescribe a required level of technological control. The chapter aims to relate ecological risk assessment to human health risk assessment in order to identify similarities and differences. Controlling the exposure of ecosystems to environmental contaminants using a risk-based approach requires that we define both an accurate measure for assessing the impacts of contaminants on ecosystems and species and a defensible process for assigning value to the predicted impacts. As applied to environmental contaminants, risk assessment involves four steps: determination of source concentrations or emissions characteristics, exposure assessment, toxicity assessment, and risk characterization. The chapter summarizes a strategy based on risk assessment for evaluating the sources of uncertainty in predictive ecological-risk assessments.
