【Special lssues】 Ocean Dumping and Contaminated Sediment
Countermeasures for Dioxin-polluted Sediment
Hirokazu Tsuji*, Shogo Tsunoda* and Tetsukazu Okada*
* Japan Sediments Management Association, Technical Committee
† Correspondence should be addressed to Hirokazu Tsuji:
（Sintomi HJ Build 7F, 1-12-7, Sintomi, Chuo-ku, Tokyo, 104-0041 Japan）

Abstract
Dioxin-polluted sediment which has been accumulating on the bottom of rivers and inner bays is one of the 20th Century's negative legacies, and an issue that should be properly managed and resolved in this century. Japan Sediments Management Association（JSMA）, to which the authors belong, has been involved in many projects to treat bottom sediments polluted by contaminants, including PCBs which have properties that are similar to dioxins and other related compounds. Based on expertise in this field, authors believe that the existing sediment management technologies can be carefully refined to safer and more environmentally-friendly so that they can be applied to dioxin-polluted sediments.
This paper summarizes up-to-data countermeasures for dioxin-polluted bottom sediment. Pollution control measures, which are one of the most important aspects of treatment work, are discussed first. Various technologies which comprise treatment work are then introduced. These include in-situ treatment technology, dredging/excavation methods, decomposing technologies and disposal methods.

Key words: dioxin, bottom sediment, pollution control measures, in-situ treatment, dredging/excavation method