Measurements of natural radioactivity in the salt cavern of the Polkowice-Sieroszowice copper mine

Due to their low radioactivity background, underground physics laboratories offer a unique possibility for investigating extremely rare phenomena like proton decay, dark matter signals or neutrino physics/astrophysics related issues. The knowledge of the natural radioactivity background is essential for the success of an underground physics experiment. The following measurements of the natural radioactivity background, in the foreseen location of an underground physics laboratory in the salt layer, in the Polkowice–Sieroszowice copper mine are presented: concentration of natural radio-isotopes from in situ obtained gamma-ray spectra and from alpha spectroscopy of rock samples, radon concentration in the air and the dose determination

Geographical distribution of 90Sr contamination in Poland

The paper presents results on determination of 90Sr in bilberry and cowberry leaves (Vaccinium myrtillus and Vaccinium vitis-idaea) and the use of these plants as bio-monitors of radiostrontium contamination in Poland. Radiostrontium was determined by mean of liquid scintillation spectrometry preceded by radiochemical separation using Sr-resin and 85Sr tracer. The approximate map of 90Sr contamination of Poland is presented. The activity ratio between 90Sr and obtained earlier data for 137Cs in the same samples is discussed. The enhancement of radiostrontium content observed in northeastern Poland seems to be the trace of hot-particles fallout from initial Chernobyl cloud, which passed over Polish territory toward Scandinavia

Radioactive Contamination of Lichens and Mosses Collected in South Shetlands and Antarctic Peninsula

Samples belonging to two species of lichen and one of moss collected on the Antarctic seashore (King George Island, Deception, Antarctic Peninsula) were analysed for gamma-emitters using HPGe gamma-spectrometry, and for alpha-emitters using alpha-spectrometry with silicon detectors. Observed 137Cs activities show large variations: from 4.1±0.4 to 74±3 Bq/kg. Total activity of 210Pb changed from <2 to 125±35 Bq/kg. The 2391240Pu activity ranged from 0.07±0.02 to 2.95±0.16 Bq/kg. The activity of 238Pu ranged from <0.02 to 0.64±0.04 Bq/kg. Maximum 238U and 234U activity was 7 Bq/kg, respectively, and 0.3 Bq/kg for 235U, whereas minimum activities were below 0.5 Bq/kg for 234U and 238U and about 0.02 Bq/kg for 235U. The 235U to 238U activity ratio for most of the samples was natural. Thorium activities were about two times lower than those for uranium. The activities of 147Sm ranged from 0.014±0.002 to 1.0±0.2 Bq/kg. One sample had relatively high activity of 241Am: 3.38±0.11 Bq/kg, another did not exceeded 1 Bq/kg. Observed activity ratios confirmed differences between mosses and lichen accumulation properties for radionuclides. Lichens are more selective for plutonium accumulation. Some radiocesium and probably also americium can be leached from them

Transuranic isotopes and 90Sr in attic dust in the vicinity of two nuclear establishments in Northern Germany

Attic dust was chosen as the test medium in order to search for traces of man-made bone seeking alpha and beta emitters. The samples were taken from 5 houses in the community of Elbmarsch situated at the river Elbe, adjacent to the Krümmel nuclear power plant and the nuclear research center of Geesthacht. Five houses in other regions of northern Germany were taken as a control. 238Pu, 239,240Pu, 241Am, and 244Cm were measured by alpha spectrometry after chemical separation. Additionally, 241Pu was measured by liquid scintillation spectrometry, and the fission product 90Sr was measured in a separate investigation. All nuclides except 244Cm showed activities above the detection limit in the Elbmarsch samples and an elevated mean concentration compared to the control. It can be concluded from the activity ratio 241Am/239,240Pu that the Elbmarsch contamination cannot be accounted for by the background levels of transuranic nuclides resulting from weapons fallout. The derived release of alpha emitters is assumed to have contributed to the induction of a leukemia cluster in children, which was observed in Elbmarsch between 1990 and 1996

Soil-to-fungi transfer of 90Sr, 239+240Pu, and 241Am

Fungi have up to now generally been used as bioindicators of radiocaesium in terrestrial ecosystems. However there is little knowledge about the behaviour of other man-made radionuclides. In the present work, we analyzed the soil-to-fungi transfer of 90Sr, 239+240Pu, and 241Am by collecting several species of fungi and the corresponding surface soil (0−5 cm) of a selected semi-natural ecosystem. The transfer of these radionuclides was then quantified by means of the traditional transfer factor, TF, defined as the ratio between the content in the fruiting bodies and in the total fraction of soil. As a general rule, the 90Sr TF values were higher than those of 239+240Pu and 241Am. This definition of the transfer factor can underestimate the transfer of radionuclides of which a large percentage are bound to soil particles. We therefore also used a definition based on the amount of radionuclide available to be transferred instead of the total content of the soil — the available transfer factor, ATF — which would be closer to the actual process of transfer. Hebeloma cylindrosporum and Lycoperdon perlatum presented 239+240Pu and 241Am ATF values that were greater than or similar to those of 90Sr. These species may thus be used as bioindicators for 239+240Pu and 241Am in a forest ecosystem

Accumulation properties of Norway spruce (Picea abies) for different radionuclides

The paper presents results for the 137Cs, 90Sr, 40K activity concentrations and 228Th/232Th, 230Th/232Th activity ratios in several samples needles from two Norway spruce (Picea abies) trees and two soil samples collected in the Tatra Mountains (Poland) area. Activities for artificial 137Cs and 90Sr show moderate values. Statistically different values were found between the mean concentration of 90Sr and 137Cs in current (C) and two years old (C+2) needles of the first tree, whereas for potassium no significant difference was observed. For the second, fallen tree, no significant difference between the mean activity concentration in needles for C+1 and C+2 was found for each radionuclide, but much lower levels of 137Cs contamination were observed. Observed values of the aggregation coefficients for 137Cs and 90Sr are presented

Elevated plutonium and americium content in skulls of small mammals

It has been found that in skull bones of small mammals have significantly higher Pu and Am concentrations than ever found in bones of any other species in areas contaminated by global fallout. Since there was no difference between skulls of rodents and insectivorous, an explanation is proposed that the contamination takes place by the inhalation of Pu and Am tiny soil particles

Activity ratios of thorium isotopes in living species compared with other environmental samples

Since about ten years our laboratory is conducting studies on the determination of Pu in many environmental samples, among them also the biological ones. Plutonium results were already discussed elsewhere [1, 4, 5, 8–21, 27]. In the course of radiochemical procedure for plutonium separation a thorium fraction was separated for each sample. Since we had not used any thorium tracer in the past, thorium activities were not determined. However, always alpha sources were prepared and then measured. This produced a relatively large archive of thorium alpha spectra from which one can study activity ratios of thorium isotopes. Two ratios seems to be interesting. The first is the Th to Th activity ratio. Both these isotopes are the Th-series members and, therefore, one might expect equilibrium. Usually this is not the case. Another subject is the activity ratio between Th and Th. One can tell that there is no relation between these two isotopes and, therefore, this ratio should not bring any information. The first isotope belongs to the U series, it is a decay product of U. The second one is just a primordial parent of the Th series. So, one can expect, that this ratio will generally reflect the activity ratio between the U and Th series for a given environment. However, this ratio might be modified by weak effects and this possibility should be taken into consideration

Gamma emmitters on micro-becquerel activity level in air at Kroków (Poland)

The Petryanov air filters combined into half-year sets were analyzed for the presence of 40K, 137Cs and 22Na by means of low-background gamma rays spectrometry. Each sample contains aerosols from more than 1 Mm3 of air. Samples were collected in ground level air at Kraków (Southern Poland) from 1996 to 2002. Activity concentrations of 40K are almost constant with the mean of 14.7± 4.5 μ Bq m−3. Activity concentrations of 137Cs, which are on the level of single μ Bq m− 3 show exponential decrease with effective half-life time of 7.07± 0.77 years. The cosmogenic 22Na shows a strong seasonal variation with significant different mean values activity concentration between 0.333± 0.095 μ Bq m−3 and 0.137± 0.045 μ Bq m−3, for summer and winter, respectively. Moreover, the activity ratio for two cosmogenic radionuclides: 22Na and measured previously 7Be show also changes with statistically significant seasonal differences. The lower values were found during winters. The mechanisms which might govern this ratio are discussed. The conclusion is that transport of 22Na during summer seems to be so much effective, that results in kind of relative depletion of stratosphere of this nuclide

90Sr, 241Am and plutonium in Barn Owl skeletons (Tyto alba Scop.) from southeast Poland

Numerous studies concerned with accumulation of several various groups of chemical compounds have been performed on Bam Owls (Tyto alba Scop.). But up to now we have no data about concentrations of radionuclides in their tissues. However, in Europe a large part of the breeding range of this species might have received fallout from Chernobyl. Nine skeletons of Barn Owls collected in 1999-2002 in southeastern Poland were analyzed for 90Sr, 241Am and plutonium. The results revealed 239+240Pu (< 0.004 Bq/kg - 0.051 ± 0.007 Bq/kg ash weight), 241Am (< 0.02 Bq/kg - < 0.06 Bq/kg ash weight) and 90Sr (9.7 ± 0.9 Bq/kg - 46.8 ± 3.6 Bq/kg ash weight) concentrations to be similar to those observed in the prey species; therefore, the conclusion is that no accumulative effect has been seen