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- Author or Editor: M. Sumiya x
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Abstract
Analytical method for the determination of129I and127I in environmental samples has been developed by using radiochemical neutron activation analysis. The129I levels in the samples such as soil (0.9–41 mBq/kg), precipitation (0.002–0.11 mBq/kg), pine needles (1.2–32 mBq/kg) and seaweed (<0.1–17 mBq/kg) collected near the nuclear facilities in Tokaimura were higher than those from the other areas in Japan. The highest129I concentration was found in surface soil (0–5 cm), and the highest129I/127I ratios were found in pine needles and precipitation. The129I/127I ratio was higher in rice paddy soil than those in wheat field soil collected around Tokaimura, while the concentration of129I somewhat higher in wheat field soil.
Abstract
A radiochemical neutron activation analytical method for the determination of129I and127I in soil samples was studied. Iodine was separated from the sample prior to the irradiation by volatilization, i.e. by combustion of the sample and trapping of the iodine in an alkaline solution together with a reducing agent. This method enables one to digest samples containing up to 100 g dry matter. The chemical yield was mostly more than 90%. After irradiation the iodine fraction was further purified by solvent extraction. The detection limit of the129I/127I ratio was 1×10–9.
Abstract
New analytical techniques using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) were applied to the determination of technetium-99 (Tc-99) and neptunium-237 (Np-237) in environmental samples. The determination of Tc-99 consists of a cyclohexanone solvent extraction method to eliminate the interference isobar (Ru-99). An anion exchange with acetic acid media and a TTA-xylene solvent extraction were used for the determination of Np-237. Technetium-95m and Np-239 were used as chemical recovery tracers in these methods. The concentrations of Tc-99 and Np-237 in the typical surface soil samples in Japan ranged form 8.1×102 to 1.8×10–1 Bq/kg-dry, from 3.3×10–3 to 8.0×10–3 Bq/kg-dry, respectively.
Abstract
A rapid separation method was developed for determination of low level promethium-147 and samarium-151. The rapid method, applied to environmental samples, provided speed and efficiency for the respective separation of Pm and Sm from other lanthanides with the simplified technique of high performance liquid chromatography (HPLC) system. The separation time of Pm and Sm in HPLC separation was shortened by stepwise eluent method of 
-hydroxyisobutyric acid as compared with a gradient eluent method of lactic acid with HPLC despite increase in sample volume for significant determination of Pm-147 and Sm-151. This method permitted the detection limit around 0.1 Bq/kg-dry-soil for Pm-147 and Sm-151 in 200 g soil sample by counting for 500 min with a liquid scintillation counter.
