RESUMO
In the context of age dating of 90Sr, the selective adsorption of zirconium ions from the mixture with strontium and yttrium by adsorbents based on TiO2 with a chemically modified surface was investigated. The general features of the separation process of strontium, yttrium, and zirconium in batch conditions were determined. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to analyze the initial and residual concentrations of the studied cations. Separation of 90Zr and 90Sr from a liquid source containing 90Sr-90Y using adsorbents based on TiO2 was performed for the first time. The ratio of 90Zr/90Sr was measured, and the age of liquid 90Sr-90Y sources was determined. In addition, we studied the age dating of 90Sr-90Y sources using a combination of liquid-scintillation counting of 90Sr and ICP-MS measurement. The results of both methods - the method of age-dating with the chemical separation of isotopes and the combination of LSC and ICP-MS analysis - agree very well and thus serve for cross-validation. Moreover, the combination of the two methods increases the confidence in the age-dating results of 90Sr-90Y sources.
RESUMO
The multiyear cultivation of Miscanthus × giganteus Greef et Deu (M.×giganteus) at the soils polluted by metal(loid)s were researched. The biomass parameters and concentrations of elements: Ti, Mn, Fe, Cu, Zn, As, Sr, and Mo were determined in the plant's organs at harvest. The same metal(loid)s were monitored in the plant's leaves throughout three vegetation seasons. The principal component analysis and general linear model approaches were applied for statistical evaluation followed by Box-Cox transformation. The difference in the distribution of elements in the plant, the content of elements in the soil, various regime of uptake to the plant tissues, and the year of vegetation were analyzed as driving factors of the phytoremediation. The results showed that the leading promoter was the factor of the zone, which was the most essential for Ti, Fe, and Cu and the smallest for Mn. The factor of differences in soil pollution was essential for Zn and Mo, much less for As, Sr, and Mn, limited for Fe, and was not seen for Ti and Cu. The factor of the interrelation effects of the zone and experiment reflected the different regime of uptake for the plant tissues was seen for two elements: more prominent for Cu and smaller for Ti. While analyzing the dynamic of foliar concentrations of the metal(loid)s during 3 years, two groups were defined. Firstly, Fe, Ni, Mn, and Sr showed stable curves with limited distribution of the plant life cycle. Secondly, As, Zn, Cu, and Mo showed different fluctuations in the curves, which can be attributed to essential influence of those elements to the plant life cycle. Further research will be focused on the application of M.×giganteus to the polluted soil in a bigger scale and comparison results of laboratory and field experiments.
