What We Have Achieved: An Introduction to a Case Study on Dioxins

Our achievements in a research project involving a case study on dioxins are presented by introducing the results. These achievements include the identification of emission sources, description of the dynamics in environmental media based on the congener-specific analysis and development of the integrated methods to evaluate and manage various types of risks due to dioxins. The risks to fetuses due to dioxins and how to manage the risks arising from chemical use are discussed. 1. Overview of the case study on dioxins Our project, entitled, “ Establishment of a scientific framework for the management of toxicity of chemicals based on environmental risk-benefit analysis,” aims at providing the Japanese society with a scientific basis for devising an environmental policy. The project consists of three major subjects: 1) to evaluate the human health risks from chemical use, 2) to evaluate the ecological risks from chemical use, various types of exploitation and fishing, and 3) to balance the risks against the benefits of chemical use. We are aiming at the development of a methodology for evaluating risks and balancing the risks against the benefits, by carrying out case studies of chemicals such as dioxins, endocrine-disrupting chemicals, DDT, benzene, mercury and indoor air pollutants. Referring to the case study on dioxins, our achievements since 1996 are presented here. An overview of the case study on dioxins is given in Figure 1. The term dioxins in this study refers to a family of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) which sometimes are abbreviated as PCDD/Fs. This case study covers four major issues: 1) exposure analysis, 2) risk evaluation, 3) identification of emission sources, and 4) a proposal of how to manage risks due to dioxins.