Non-controlled usage of mineral fertilisers in agriculture land of Kazakhstan is a concerning issue, due to possible contamination of the soil by radionuclides. Pot experiment of growing of R. sativus with application of mineral fertilisers was carried out under natural conditions. Two commonly used mineral fertilisers, mono-potassium phosphate and ammonium nitrate, were chosen in the frame of current research to determine the impact of mineral fertiliser on transfer of natural radionuclides from soil to R. sativus edible part. For this goal, the activity concentrations of natural radionuclides U-234, U-238, Th-230, Th-232 and Ra-226, were determined in both R. sativus edible part and the investigated soil by using alpha-particle spectrometry. The highest activity concentrations were found for R. sativus edible part growing on soil that was fertilised by mono-potassium phosphate and were equal to 174 +/- 17, 134 +/- 15, 62 +/- 4, 15 +/- 2 and 2.8 +/- 0.6 Bq/kg for U-234, U-238, Th-230, Th-232 and Ra-226, respectively. The results of soil -to-R. sativus edible part transfer factor for different radionuclides varied depending on the mineral fertiliser used. For evaluation of impact during consumption of R. sativus edible part by a population of Kazakhstan, annual effective ingestion dose and excess lifetime cancer risk were determined. The highest annual effective ingestion dose was found for R. sativus edible part cultivated in mono potassium phosphate-fertilised soil and was equal to 4.4 mu Sv year-1.

The concentration and isotopic composition of mercury (Hg) were determined in glacier core samples from Canadian Arctic ice caps dating from preindustrial to recent time (early 21st century). Mean Hg levels increased from <= 0.2 ng L-1 in preindustrial time to similar to 0.8-1.2 ng L-1 in the modern industrial era (last similar to 200 years). Hg accumulated on Arctic ice caps has Delta Hg-199 and Delta Hg-201 that are higher (similar to-1 to 2.9 parts per thousand) than previously reported for Arctic snow impacted by atmospheric Hg depletion events (mostly <-1 parts per thousand), suggesting that these events contribute little to Hg accumulation on ice caps. The range of delta Hg-202, Delta Hg-199, and Delta Hg-201 in glacier cores overlaps with that of Arctic Hg-(g)(0) and of seawater in Baffin Bay and also with that of midlatitude precipitation and industrial Hg sources, including coal and Hg ores. A core from Agassiz ice cap (80.7 degrees N) shows a similar to+1 parts per thousand shift in delta Hg-202 over the nineteenth to twentieth centuries that could reflect changes in the isotopic composition of the atmospheric Hg pool in the High Arctic in response to growing industrial emissions at lower latitudes. This study is the first ever to report on historical variations of Hg stable isotope ratios in Arctic ice cores. Results could help constrain future modeling efforts of the global Hg biogeochemical cycle and the atmosphere's response to changing Hg emissions, past and future.

Summary Different radiometric techniques for the determination of 238U, 226Ra and 210Pb are presented and compared in terms of detection limits with mass spectrometric techniques. It can be concluded that when samples with low activity concentrations have to be measured, the method of choice in the case of 238U should be either RNAA/INAA or alpha particle spectrometry. In the case of 226Ra and 210Pb the best performance can be expected by the alpha spectrometry, whereas drawback of waiting for establishing secular radioactive equilibrium of 210Pb with 210Po makes techniques like beta counting and LSC more attractive for the determination of 210Pb. In addition, a case study on monitoring the former uranium mine Žirovski vrh is presented along with the used methodology and the summarised measurement results.

Different radiometric techniques for the determination of U-238, Ra-226 and Pb-210 are presented and compared in terms of detection limits with mass spectrometric techniques. It can be concluded that when samples with low activity concentrations have to be measured, the method of choice in the case of U-238 should be either RNAA/INAA or alpha particle spectrometry. In the case of Ra-226 and Pb-210 the best performance can be expected by the alpha spectrometry, whereas drawback of waiting for establishing secular radioactive equilibrium of Pb-210 with Po-210 makes techniques like beta counting and LSC more attractive for the determination of Pb-210. In addition, a case study on monitoring the former uranium mine. Zirovski vrh is presented along with the used methodology and the summarised measurement results.

Although the influential area of the former uranium mine at Zirovski vrh, Slovenia has been under continuous radiological monitoring, more detailed radioecology studies, focused on assessing mobility and bioavailability of deposited radionuclides, were initiated about five years ago. The mobility of 238U, 234U, 230Th and 226Ra was studied applying two sequential extraction protocols. The results revealed that both sequential extraction protocols are not comparable as the data obtained are protocol- and radionuclide-dependent. It was found that the most mobile ones were uranium isotopes, followed by 226Ra and 230Th. In addition, uptake of particular radionuclides by the wetland plants (Molinia arundinacea, Juncus effusus and Caltha palustris) grown in soils contaminated with seepage waters from the tailings was studied. The plants contained higher levels of 238U, 226Ra and 230Th compared to the plants from the control site. Activity concentration of 226Ra was the highest for all three plant species. Activity concentration of natural radionuclides in milk collected from the area of Zirovski vrh was comparable to the reference location, except for uranium where the content was higher. The combined annual effective dose for adults consuming milk from the Zirovski vrh area is 13 ± 2 μSv yr−1.

Radium-226 is one of the best known long-lived α-emitters abundantly present in the environment. The determination of radium isotopes in environmental samples usually requires a demanding chemical separation before measurement and quantification. Each step in the chemical separation process can involve losses of the analyte, therefore it is of vital importance that the recovery of the whole radiochemical procedure is evaluated. The emphasis of the work presented was determination of the chemical recovery using the different yield tracers Ra-223, Ra-225 and Ba-133.