Environmental risk evaluation of chemicals: achievements of the project and seeds for future––development of metrics for evaluating risks

Achievements of the research project entitled “Establishment of a scientific framework for the management of toxicity of chemicals based on environmental risk–benefit analysis” supported by the JST were introduced and reviewed, focusing on the development of the methodology for estimating risks; human health risks and ecological risks. The usefulness of loss of life expectancy as a metric for evaluating cancer and noncancer risks was demonstrated. To evaluate ecological risks, three metrics, 1/T, logT and T, developed based on the mean extinction time (T) of species were proposed. Then, their implication and feasibility were examined in terms of what ecological system should be conserved and how easily people can understand the implications of metrics. Protocols for estimating human health risks and ecological risks are illustrated.