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  • Author or Editor: S. Oikawa x
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Abstract  

A rapid analytical method of Pu in environmental samples by alpha-ray spectrometry and high-resolution inductively coupled plasma mass spectrometer (HR-ICP-MS) using a 3M Empore anion exchange resin disk for solid phase extraction has been developed. A trace amount of Pu was quantitatively adsorbed with an Empore anion exchange resin disk (47 mm diam.) at a flow rate of 150–200 ml/min from 8M HNO3 sample solution. The disk was washed with 10 ml of 8M HNO3 and 12 ml of 9M HCl and then the Pu was quantitatively eluted with 15 ml of 1M HNO3/0.03M ascorbic acid solution. The time needed to separate Pu from the sample solution with the present method was about 20 minutes. The separated Pu was determined with alpha-ray spectrometry and HR-ICP-MS. The present method was applied to the determination of Pu in the certified reference material (IAEA-135) and the environmental soil sample. The analytical results were almost in good agreement with the literature values.

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Abstract  

Long-lived radionuclides,99Tc,137Cs,237Np, Pu isotopes and241Am were determined in the long sediment cores collected from nine intertidal sites around the west Cumbria of the Irish Sea, UK. The inventories of all nuclides measured varied considerably among the sampling sites, but generally their inventories decreased with increasing distance from Sellafield. Furthermore, the inventory ratios with respect to relationship with distance from Sellafield enabled comparison of transport behavior of99Tc,137Cs,237Np and241Am compared with239,240Pu. As a consequence, the apparent fractional rate of solution transport to the intertidal sediment was found to increase as follows:99Tc>137Cs>237Np>239,240Pu≥241Am.

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Summary  

A major concern with leaking petroleum is the environmental contamination by the toxic and water-soluble components such as benzene, toluene and xylenes (BTX). These hydrocarbons have relatively high pollution potential because of their significant toxicity. All BTX compounds are depressants to the central nervous system. Consequently, BTX are priority pollutants and their occurrence has led to the development of several physical, chemical and biological methods for their removal. The use of nuclear technology for protection and conservation of the environment, by the destruction of toxic organic compounds present in the environmental, drinking water, soils and industrial sewage has been the object of study of several authors in Brazil and in the world. The objective of this paper is to present the preliminary results of the study of contamination of the seawater by the main pollutants of the output and transport of petroleum, such as benzene, toluene and xylene, and their removal by the exposure to the ionizing radiation.

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Abstract  

The 137Cs, 238Pu and 239,240Pu activity concentrations were determined together with the atomic ratios of 240Pu/239Pu for the soil samples at 19 sites from the Ust"""-Kamenogorsk district, located more than 300 km east of the Semipalatinsk nuclear test site (SNTS). The mean areal deposition of 137Cs ranged from 1,500 to 4,100 Bq/m2. However, some hot spot-like areas showing high concentrations of 5,500–7,700 Bq/m2 were foundat some sites within the city. The 239,240Pu levels ranged from <50 to 510 Bq/m2, however most of them ranged between 120–200 Bq/m2. These levels are nearly the same as those around the Semipalatinsk City. At most of the sites within the city and its adjacent areas, both nuclides were found in the soil layers up to a depth of 30 cm. A fraction of 20–50% of 239,240Pu was not leached by hot digestion with concentrated HNO3 containing a small amount of H2O2. Generally, such tightly bound fraction showed a trend to decrease with increasing distance from the SNTS. The fraction of these radionuclides that were deposited in Ust"""-Kamenogorsk district from global and from SNTS fallouts have been determined using the 240Pu/239Pu atomic ratios in both Pu fractions: one which can be leached with hot HNO3 + H2O2 and another that is a non-leacheable for each soil layer of core samples. As a result a fraction of 21–80% (mostly 30–60%) of total 239,240Pu were found to be due to the local fallout of Pu from the SNTS debris. For 137Cs, the contribution (mostly 10–20%) of local fallout from the SNTS were estimated to be far lower as compared to 239,240Pu.

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