| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1993: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1992: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
A variety of components of surface soil is known (parent rocks, clay minerals, organic matters, microorganisms and so on). The contribution of the main component to the sorption of radioiodine in surface soil has been investigated. Radiotracer experiments on the sorption of I^- (iodide) and IO_3^- (iodate) from water to soil have been carried out. Soil samples were collected in forest (Fukui Pref.), field, paddy field and seashore (Ibaraki Pref.). After incubating with tracer solution in a definite days, the soil samples were separated. From radioactivities of two phases the distribution ratio of radioiodine sorption to soil system were calculated. The sorption of I^-by soil was markedly reduced through treatments of air-drying, heating the soil prior to equilibration with water. The sterilization by chloroform fume or irradiation of gamma-ray also reduces the distribution ratio. The measurement of particle size distribution, quantities of water contents, organic matter and microorganisms and pH of soil solution, and other chemical or physical analysis have been carried to estimate the soil properties. Conclusively, the microorganisms has much influence on the sorption of radioiodine as inorganic and organic matter in surface soil.
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