IS-16 : Preliminary Estimate of Mercury Distribution of Disaster Wastes Generated by the Great East Japan Earthquake = IS-16 : Preliminary Estimate of Mercury Distribution of Disaster Wastes Generated by the Great East Japan Earthquake

다국어 초록 (Multilingual Abstract)

1. Background The great earthquake with the magnitude of 9.0, called as Great East Japan Earthquake, attacked East Japan area on 11th Mar. 2011 and caused following tsunami. The earthquake and tsunami generated massive disaster wastes which are still preventing from disaster recovery. Therefore, disaster wastes management is important to recover local society, economy, and environment. This study focuses on mercury, which is toxic heavy metal and can cause Minamata deceases, contained in huge amount of disaster wastes. Because some daily life products and medical products like fluorescent light, blood pressure manometer, and mercury-type thermometer contain mercury, the management, treatment, and disposal of disaster wastes might have significant impact on mercury emission to the environment. In this context, the purpose of this study is to estimate potential mercury distribution of disaster wastes preliminarily. 2. Method At first, the authors estimated the total amount of disaster wastes by two methods. The first estimate was according to emission factors reported based on some past earthquake disaster records. The other was according to summarized operational data of some disaster waste treatment facilities. It should be noted that these estimates should need great verification because they were based on many assumptions. Although disaster wastes have some categories like combustible, wood, and metals, their summation would be reported here. Mercury distribution of disaster wastes was calculated based on mercury content of each waste category. It also should be noted that mercury content would have non-negligible uncertainty. 3. Results and discussion Estimated total amount of disaster wastes are summarized in Table 1. There are large differences between two cases for sea sediment. This needs further study for the verification. Potential mercury distribution of disaster wastes is shown in Fig. 1. Medical wastes and fluorescent lumps are major mercury sources. Around 39% of mercury contained in disaster wastes might incorporated into cement kilns, which recycled disaster wastes as cement production resources. Although recycle of disaster wastes is preferable from the viewpoint of disaster recovery, it might have non-negligible impact on mercury emission to the atmosphere. 4. Conclusion The total amount of disaster wastes, generated by Great East Japan Earthquake and following tsunami, and potential mercury distribution of disaster wastes were estimated preliminarily. This suggests that medical wastes and fluorescent lumps might be large mercury sources. However, these estimates should have large uncertainty and needs further verification.