Mineralogical and geomicrobial examination of soil contamination by radioactive Cs due to 2011 Fukushima Daiichi Nuclear Power Plant accident

• Published in: Physics and chemistry of the earth. Parts A/B/C Vol. 58-60; pp. 57 - 67
• Main Authors: Akai, Junji, Nomura, Nao, Matsushita, Shin, Kudo, Hisaaki, Fukuhara, Haruo, Matsuoka, Shiro, Matsumoto, Jinko
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2013
• Subjects: Accidental contamination; Bacteria; Bacterial sorption; Cesium; Culture; Fukushima; Globules; Leaves; Montmorillonite; Nuclear accidents; Nuclear power generation; Recirculation; Sorption; TEM; Vermiculite; Fukushima; Leaves; Cesium; Recirculation; TEM; Bacterial sorption
• ISSN: 1474-7065; 1873-5193
• DOI: 10.1016/j.pce.2013.04.010

•Various bacteria from the environments in Fukushima and pure strains experimentally absorbed Cs.•TEM observation revealed highly concentrated Cs–P globules inside the bacterial body.•Results of sorption and desorption experiments of Cs by clays, leaves, and zeolite were compared.•Strength and capacity in sorption of Cs is in the order of zeolite>phyllosilicate>leaves.•The future diffusion and recirculation behavior of Cs in the environment was discussed. Soil contamination by radioactive Cs from Fukushima Daiichi Nuclear Power Plant accident was investigated. Absorption and desorption experiments of Cs were conducted for several phyllosillicates (kaolinite, sericite, montmorillonite, vermiculite, chrysotile and biotite), zeolite and solid organic matter (dead and green leaves). The results confirmed the characteristic sorption and desorption of Cs by these materials. The 2:1 type phyllosilicate, especially, vermiculite and montmorillonite absorbed Cs well. Heated vermiculite for agricultural use and weathered montmorillonite also adsorbed Cs. Leaves also absorbed Cs considerably but easily desorbed it. In summary, the relative capacity and strength of different materials for sorption of Cs followed the order: zeolite (clinoptilolite)>2:1 type clay mineral>1:1 type clay mineral>dead and green leaves. Culture experiments using bacteria of both naturally living on dead leaves in Iitate village, Fukushima Pref. and bacterial strains of Bacillus subtillis, Rhodococus erythropolis, Streptomyces aomiensis and Actinomycetospora chlora were carried out. Non-radioactive 1% Cs solution (CsCl) was added to the culture media. Two types of strong or considerable bacterial uptakes of Cs were found in bacterial cells. One is that Cs was contained mainly as globules inside bacteria and the other is that Cs was absorbed in the whole bacterial cells. The globules consisted mainly of Cs and P. Based on all these results, future diffusion and re-circulation behavior of Cs in the surface environment was discussed.