On the influence of soil properties on the transfer of 137Cs from two soils (Chromic Luvisol and Eutric Fluvisol) to wheat and cabbage.

Two types of soils (Eutric Fluvisol and Chromic Luvisol) and two crops (wheat and cabbage) were investigated for determination of the transfer of 137Cs from soil to plant. Measurements were performed using gamma-spectrometry. Results for the soil characteristics, transfer factors of the radionuclides (TF), and conversion factors (CF) (cabbage/wheat) were obtained. The transfer of 137Cs was higher for Chromic Luvisol for both the plants. Statistically significant dependence of TF of 137Cs on its concentration in soil was established for cabbage. Dependence between K content in the soil and the transfer factor of 137Cs was not found due to the high concentrations of available K. Use of bioconcentration factor (BCF) (ratio between the activity concentration of a radionuclide in a reference plant to its concentration in another plant) is demonstrated and proposed for risk assessment studies.

On the possibilities of inductively coupled plasma mass spectrometry for analysis of archaeological bones for reconstruction of paleodiet.

The possibilities of inductively coupled plasma atomic mass spectrometry for determination of elemental composition of archaeological bones for reconstruction of paleodiet are discussed. The interferences of different polyatomic ions on the determination of Fe, Cu, Mg, Mn, Zn, and Zr are investigated and evaluated. Thus, a method for the determination of Al, As, Ba, Mg, Pb, Sr, V, Zn, and Zr is proposed and is validated by analysis of IAEA-SRM-H-5 (animal bone). The applicability of the proposed procedure is demonstrated analyzing real archaeological bone samples dated to 4th century b.c. and the results are compared with the data obtained by inductively coupled plasma atomic emission spectrometry.

Concentration of caesium-137, cobalt-60 and potassium-40 in some wild and edible plants around the nuclear power plant in Bulgaria.

The activities of 137Cs, 60Co and 40K were determined in samples of wild (Taraxacum officinale, Plantago lanceolata and Populus nigra 'Italica') and edible (vegetable, corn, fruit) plants as well as soil collected from the 30 km safety zone of the Bulgarian NPP "Kozloduy" and comparisons with earlier measurements and analyses of samples from other regions and with literature values were performed. The derived transfer factors for 137Cs and 40K from soil to plants ranged between 0.002 and 0.009 for 137Cs, and between 0.09 and 0.35 for 40K. The individual effective dose (calculated from the present results and data on the activity of other foodstuffs and from information about dietary habits) comprises 4.5% of the annual dose limit.

Determination of rare earth elements in soils and sediments by inductively coupled plasma atomic emission spectrometry after cation-exchange separation.

The influence of matrix elements such as Ba, Ca, Fe, K, Na and Ti, on the inductively coupled plasma atomic emission spectrometry determination of the rare earth elements in soils and sediments is investigated and analytical lines with minimal interferences are chosen. The analysis of certified reference materials by two calibration methods (pure rare earth solutions and IAEA-Soil 5) and after cation-exchange proved that calibrations with IAEA-Soil 5 increase the number of accurately determined rare earth elements (REE), permitting the instrumental determination of Ce, Eu, La, Nd, Tb, Yb and Y in soils and some sediments. The cation-exchange procedure permits the determination of 12 REE with very good accuracy (below 10%) and detection limits varying between 0.05 (Eu, Tb, Yb) and 0.5 (Er) mg kg(-1).

On the microwave digestion of soils and sediments for determination of lanthanides and some toxic and essential elements by inductively coupled plasma source mass spectrometry.

Four digestion procedures for microwave dissolution of soils and sediments are investigated. Accurate results (accuracy better than 10%) for lanthanides, Be, Bi, Te, Th, U and Y are obtained only after an overnight stay with a mixture of 2 ml 48% HF and 2 ml 65% HNO(3) and afterwards stepwise microwave digestion with 1 ml 48% HF and 10 ml 5% H(3)BO(3). Only As is not be to be determined by this procedure due to significant interferences from Eu, Nd and Sm. For all other elements, accurate results are obtained by all four procedures.

Distribution of lanthanoids, Be, Bi, Ga, Te, Tl, Th and U on the territory of Bulgaria using Populus nigra 'Italica' as an indicator.

The concentrations of lanthanoids, Be, Bi,Ga, Te, Tl, Th and U have been determined using ICP-MS for 100 standardized samples of poplar leaves collected from the territory of Bulgaria. The investigated elements are log-normally distributed on the territory. Using cluster analysis of the analytical data the samples were grouped according soil type on which the plants are growing.

Screening of heavy metal pollution in Bulgaria using Populus nigra 'Italica'.

The pollution with As, Cd, Co, Cr, Cu, Fe, Mn, Pb, Sb and Zn on the territory of Bulgaria has been evaluated using standardized samples of leaves of Populus nigra 'Italica' collected during the last 10 years. Background values for the respective elements are established in the leaves of the plant. The comparisons of urban and industrial pollution to some other European countries indicates similar or lower concentrations. Using cluster analysis of the analytical data the territory of Bulgaria is divided into six regions with different pollution levels.