Yoshiko Kawabata

Variation Of Uranium Isotopic Composition In Soil Within The Jco Grounds From The 30 September 1999 Criticality Accident At Jco, Tokai-mura, Japan

Following the 30 September 1999 criticality accident at JCO, 29 surface and 3 core soil samples were collected inside and outside the JCO grounds to evaluate possible contamination by 235U-enriched uranium (18.8%) being handled at the time of the accident. Uranium (234U, 235U, and 238U) and thorium (228Th, 230Th, and 232Th) isotopes were determined by alpha-spectrometry and ICP-MS after radiochemical separation. Concentrations of 238U and 234U ranged from 11.3 to 63.5 and 11.6 to 360 mBq g−1, respectively. Higher amounts of 238U and/or 234U were found in the vicinity of the uranium conversion building. The calculated 234U/238U activity ratios ranged from a 1.0 radioactive equilibrium value to an unusually high 5.7 value. Several of the soil samples showed considerably higher 235U/238U atomic ratios (1.06–4.37%) than 0.725% for natural uranium. Based on the assumption that measured U-series nuclides in soil samples taken from the JCO grounds were almost at radioactive equilibrium up to 230Th, excess uranium could be calculated for each sample. The results suggest that the excess uranium in the soils have lower 235U/238U atomic ratios (a few %) than the 18.8% enrichment of the precipitation tank uranium.

The Structural and Functional Characteristics of Asiatic Desert Halophytes for Phytostabilization of Polluted Sites

Phytoremediation, the use of plants to extract, sequester, and/or detoxify pollutants through biological processes is an effective, in situ, non-intrusive, low-cost, ecologically friendly, socially accepted technology to remediate polluted soils. Crystalline to fibrillar wax formations, appressed to surfaces of guard cells appear to originate from guard cells in the vicinity of the stomatal aperture. Formations may arise from evaporation of plant water at the interface between stomatal antechambers and substomatal cavities, leaving salt ions behind to precipitate. Many questions remain unanswered regarding their ecological and physiological significance as well as their occurrence and prevalence in both time and space. Such functions would be of considerable adaptive value in the light of their possible relationships to the impact of pollutants. An attempt has been made here to address these questions by analysing the morphology of salt glands and intracellular salt crystals using SEM micrographs of Salsola, Eremopyrum, Aeluropus litoralis, Tamarix and other desert plants.

Neutron activation analysis and inductively coupled plasma-mass spectrometry for the determination of elements in tree stems

Mn, Zn and Al concentrations of ume, sakura and sugi stems determined by ICP-MS using a simple pretreatment were compared with those determined by INAA. We obtained a considerably good agreement between the two methods. ICP-MS using simple pretreatment was found to be useful in analyzing the elements in tree stems.

Uranium Pollution of Grand Water in Karakalpakstan, Uzbekistan

We investigated uranium concentrations in ground water in Karakalpakstan, Uzbekistan. In the rural area of Karakalpakstan, main drinking water are ground water. In the Half of sampling points for drinking water, uranium concentrations exceeded the WHO (2008) guideline level for drinking water. Since uranium is a suspected carcinogen that can also have a toxic effect on kidneys. However, WHO addressing only the chemical aspects of uranium prescribed that uranium concentrations in drinking water. The effect of uranium exposure from drinking water on people in these areas is significant.