Abstract
The large amount of tsunami deposit generated in the Great East Japan Earthquake remains an acute obstacle to the rehabilitation and reconstruction of the devastated coastal area in northeastern Japan. Since the tsunami deposit may contain hazardous substances leaked from damaged facilities, its chemical composition needs to be evaluated before putting it back into use (as material) or disposing of it. This article discusses the chemical composition of tsunami deposit from the viewpoint of land use and location of facilities in the flooded areas and explored the possibility of zoning areas by the level of potential pollution of tsunami deposit. As a result, all tsunami deposit samples containing high level of hazardous substances were sampled near facilities that are related to the particular detected substances. This suggests that it may be possible to zone off the flooded area based on the information regarding land use and location of facilities in the areas. Based on this discussion, a flow for this zoning process was proposed. Toward better zoning, it will be important to create a comprehensive list of facilities that can be sources of hazardous substances as well as to organize information on the stockpile of hazardous substances at each facility.
