TITLE:
Removal of Radioactivity from Sediment Mud and Soil and Use for Cultivation of Safe Vegetables in Fukushima, and Removal of Toxic Metals Using Photosynthetic Bacteria
AUTHORS:
Kei Sasaki, Kaoru Nakamura, Kenji Takeno, Hidenori Shinkawa, Nachiketa Das, Ken Sasaki
KEYWORDS:
Immobilized Photosynthetic Bacteria, Cs and Sr, Heavy Metals, Removal of Radioactivity, Radioactive Cs, Safe Vegetables
JOURNAL NAME:
Journal of Agricultural Chemistry and Environment,
Vol.4 No.3,
August
20,
2015
ABSTRACT: The immobilized photosynthetic bacterium, Rhodobacter shpaeroides SSI (SSI), cultured on porous 2 cm ceramic beads, effectively removed and recovered 20 mg/L of non-radioactive Cs (almost 100%) and Sr (≌50%), after 3 - 5 days of aerobic treatment. Toxic and heavy metals such as Hg, Cr, Pb and As were also removed, almost 100%, after 6days of aerobic treatment. A practical method of removal of radioactivity of 10 - 30 μSv/h, caused mainly by radioactive Cs released from the accident at the Daiichi Nuclear Power Plant on 11th March 2011, from sediment mud and soil in Fukushima, Japan, was also carried out. Using immobilized SSI beads, more than 90% and 42% - 73% of radioactive Cs was removed and recovered from sediment mud and soil, respectively, after 3 - 14 days of aerobic treatment in an outdoor 60 L vessel. The weight and mass of the harvested beads could be reduced by more than 97% after desiccation. This technology of removal and recovery had therefore, considerable advantages over other technologies that demanded very large storage facilities in Fukushima. After removal of radioactivity from polluted soil, vegetables like Komatsuna (Turrip leaves) and Chingensai (Green pakchoi) were cultivated on remediated soil. Safe vegetables grown on these treated soils showed a radioactivity content lower than the recommended limit for edible foods in Japan, i.e. less than