Gram-negative bacteria responsible for insoluble technetium formation and the fate of insoluble Tc in the water column above flooded paddy soil.
We studied the characteristic gram-stain of Tc insolubilizing bacteria using various antibiotics, and the fate of insoluble Tc in a water column above flooded paddy soil to clarify Tc behavior in paddy fields. The formation of insoluble Tc in water column samples was inhibited by the addition of antibiotics, especially reagents against gram-negative bacteria. For a sample without antibiotics, insoluble Tc formation increased with time, and the maximum amount of insoluble Tc was observed on day 4 of incubation with (95m)Tc. In contrast, concentrations of ferrous ion decreased with time. These results suggested that gram-negative bacteria were mainly responsible for insoluble Tc formation, and that these bacteria were able to transform soluble Tc to insoluble forms under oxidizing conditions.
Ishii
Nobuyoshi
N
Office of Biospheric Assessment for Waste Disposal, National Institute of Radiological Sciences, Anagawa 4-9-1, Inage-ku, Chiba-shi 263-8555, Japan. nobu@nirs.go.jp
Uchida
Shigeo
S
D004190:Disasters; D006090:Gram-Negative Bacteria / Q000378:metabolism*; D012275:Oryza; D010084:Oxidation-Reduction; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology; D012990:Soil Pollutants, Radioactive / Q000032:analysis; D012995:Solubility; D013667:Technetium / Q000032:analysis* / Q000737:chemistry; D013997:Time Factors; D014871:Water Microbiology; D014875:Water Pollutants, Radioactive / Q000032:analysis
D012987:Soil; D012990:Soil Pollutants, Radioactive; D014875:Water Pollutants, Radioactive; D013667:Technetium