Dispersion of radon in the atmosphere around old uranium mill tailings

This paper presents the results of investigations of radon levels in the atmosphere around old uranium tailings aiming to estimate the influence of inactive uranium sites to the population and personnel. These tailings are situated in the area of a former uranium processing activity of a Pridniprovsk Chemical Plant in the city of Dniprodzierzhinsk. The radon-222 measurements have been carried out using an etched track system TRACK 2010Z. The minimum detectable activity of radon-222 has made up 2 Bq/m3 with the exposure of 30 days. Corresponding data sets of radon-222 and its daughters have been analysed. We have calculated distribution of the radon equilibrium factor (F), i.e. the ratio between radon and radon daughters for the investigated site. Our study shows a contrast spatial radon-222 dispersion in the atmosphere, while radon-222 is lowered to the background levels. The average value of the F makes up 0.146 for the undisturbed open atmosphere. Atmospheric inversions cause a significant rise of F that goes up to 0.487. The present research has been carried out within the frameworks of the STCU project no. 3290

Plutonium and other alpha emitters in mushrooms from Poland, Spain and Ukraine

The paper presents results on Pu, U and Th isotope activity concentration measurements in some mushroom samples collected in Poland, Spain and Ukraine. The sampling sites differ a lot with regard to observed levels of Pu, its origin and isotope ratios as well as the environmental properties. Some of the Polish samples were collected in the north-eastern part of the country with up to 30 Bq/m2 of Chernobyl Pu deposition. Other Polish and the Spanish samples are from areas with almost exclusively global fallout Pu present. Ukrainian samples were collected in a highly contaminated area with a deposition of about 3.7 kBq/m2 of Chernobyl 239+240Pu. The maximum 239+240Pu activity concentration was found equal to (54±4) Bq/kg (dw—dry weight) for a Ukrainian Cantharellus cibarius sample. Ukrainian samples have an extremely high radiocesium level, with maximum of (51±4) MBq/kg (dw). The maximum 239+240Pu activity concentration for Polish samples was (81±5) mBq/kg (dw) for Xerocomus badius. From the isotopic ratio in this sample it can be concluded that Chernobyl fallout is the origin of Pu. More than twice as large was the Spanish maximum for Hebeloma cylindrosporum but with only global fallout Pu. Some aspects of the transfer of nuclides to fruit bodies is discussed and in some cases the transfer factors or aggregation coefficients were calculated. Especially high transfer factors were found for Hebeloma cylindrosporum from Spain