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- Author or Editor: Y. Ohta x
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Abstract
The concentration of Ra isotopes in environmental water can be determined from the amount of Ra isotopes recovered in two successive batch operations a using cation exchange resin. The present analytical method is applicable to 10 liter of sample water having a Ra concentration larger than 10 mBq/l and is also applicable to the ordinary underground water of less than 1 mBq/l by use of 50 liter of sample water. In case where Ra concentration is extremely low, Mn-impregnated acrylic fiber can be used with a larger volume of water sample as an absorbent by soaking it in the water.
Abstract
The uptake behavior of Am3+ was investigated by using alginic acid and alginate polymer gels. The affinity of radioactive nuclides for carboxyl groups in gel matrices increased in the order of Na+ < Cs+ < Co2+ < Pd2+, Sr2+, Fe3+ < Eu3+, Am3+. Among alginate gels, calcium alginate exhibited relatively higher uptake rate and distribution coefficient of Am3+. The column packed with calcium alginate beads was effective for the removal of trace amounts of Am3+ from acidic nitrate solutions.
Abstract
Samples of hair from 370 subjects were analysed by neutron activation. The samples were taken from residents of nine different countries: Japan, France, Ivory Coast, Brasil, Paraguay, Canary Islands, Papua New Guinea, Italy and New Zealand. The selenium determination was made using the76Se(n,
)77mSe reaction.It was found that the average selenium concentration in the hair of Japanese subjects, both those living in Japan and those living in foreign countries was higher (total average: 0.59±0.14 mg/kg) than those of subjects from other countries (total average: 0.42±0.13 mg/kg).Our results from the determination of the selenium concentration in the hair of individuals from different countries show significant differences between different countries, nevertheless, the selenium content in human hair was small amounts. Since this is likely due to differences in diet. This method was able to analyze quickly for many samples.
Abstract
Groundwater age was determined by 85Kr/Kr specific activity of gases dissolved in groundwater at Kumamoto Area, in which newly developed Kr extraction system and liquid scintillation counting technique for 85Kr were applied. Apparent mean residence times observed were 8.2 ± 0.7 years and 20.7 ± 0.6 years for the groundwater taken from a well at the recharge area and that from an artesian borehole at the discharge area, respectively showing a consistent age trend estimated from the observed groundwater flow system of Kumamoto Area and also that determined using environmental tritium. Similar mean residence times of 85Kr and tritium were observed at the discharge area but the mean residence time of 85Kr at the recharge area was younger compared to that of tritium, probably due to mixing of river water containing recent 85Kr high in concentration into groundwater flow coming from the northern upland’s recharge area. The mean residence time of the groundwater flow coming from northern upland area and a traveling time of the groundwater between two sampling points were estimated by a simple model assuming mixing the river water with the groundwater and a piston flow between two sampling points.
