持続的稲作を目指した放射能汚染土壌におけるイネからのエタノール生産

摘要

平成23年3月11日に東北地方の太平洋沿岸での大地震と津波に加えて，福島県では東京電力福島第一原子力発電所が被災した。地震により外部電源および非常用ディーゼル発電機が故障し全交流電源が喪失した。このために冷却作業が不可能になり外部から水を注入した。しかし，格納容器内の圧力が高まったために，内部のガスを外部へ排気するベント操作を行ったが，これに伴い放射性を帯びた気体が屋外に放出されることになった。さらに，大地震の翌日1号機では原子炉冷却水喪失による核燃料温度上昇に伴い水素が大量に発生し水素爆発が起こり，さらに2号機と3号機の爆発に加えて4号機に火災が生じ汚染が拡大した。%Radioactive species such as ~(137)Cs were discharged from Fukushima Daiichi Nuclear Power Plant which was severely damaged by the enormous earthquake and tsunami. Cropland has been radioactively contaminated by ~(137)Cs etc. and it seems impossible to plant rice due to the non-suitability for food. According to the reports, ~(137)Cs transferred into the rice from soil is less than 1% on the average. Therefore, it is expected that the concentration of ~(137)Cs in bioethanol will be well below the tentative restriction value even if bioethanol could be produced from the rice. It is proposed that the rice field should be filled with water to avoid the flow of runoff contaminated by radioactive cesium compounds because they are insoluble in aqueous phase and that bioethanol should be produced from the rice in order to maintain the multifunction of rice field and to continue the agriculture. If rice farming is halted and neglected, agricultural function of rice field as well as local community will be permanently destroyed.