【Special lssues】 Ocean Dumping and Contaminated Sediment
Removal Standards and Control Measures for Bottom Sediments Contaminated by Toxic Substances in Japan
Masaaki Hosomi
Tokyo University of Agriculture & Technology Department of Chemical Engineering, Professor
（2-24-16 Naka-cho, Koganei-city, Tokyo, 184-8588 Japan）

Abstract
Environmental Water Quality and Effluent Standards were established in Japan in order to control water pollution caused by toxic substances. Since public water areas also hold sediments containing toxic substances that detract from water quality, releasing dangerous toxins and causing the bio-accumulation of toxins in fish and shellfish, these standards are not always sufficient for the protection of human health. The Environment Agency has therefore set up the “Provisional Removal Standard” for bottom sediment that contains mercury and PCB. This procedure, based on risk assessment for mercury in bottom sediments, has been adopted for the development of a removal standard for mercury. In the case of PCB, however, an empirical relationship between PCB concentrations in bottom sediments and PCB concentrations in fish has been adopted. In this paper, an environmental quality standard for dioxins found in bottom sediment is also introduced.

Key words: mercury, PCB, dioxin, sediment, environmental quality standard