[en] Special features and volumes of radioactive wastes of natural and engineering objects decontamination in Belarus lands contaminated by radionuclides due to the accident at the Chernobyl Nuclear Power Plant are characterized. Data of their burial conditions and of ecological efficiency of decontamination of low background radiation territories are cited

[en] This work reports a new method for calculating the external dose-rate as a function of height above land that has been contaminated with a surface deposition of ¹³⁷Cs. Unlike previous work this method accounts for vertical migration of ¹³⁷Cs using the Advection Dispersion Equation (ADE) with appropriate parameters. The results have been successfully verified with field measurements from the ¹³⁷Cs contaminated regions within the Republic of Belarus. The method also correctly predicts the observed variation of dose-rate with elevation above the soil surface and it is shown how this method can be used to predict the reduction in surface dose-rate after remediation measures such as deep ploughing have taken place

[en] A firm tendency outlined in recent years consists in using the lithosphere as a site of disposal of highly toxic and power rich radioactive wastes, which extends considerably the range of problems connected with the geologic reasons for these measures in every definite case. A traditional information on a geologic object, on physical-chemical, geotechnical and hydrogeologic processes occuring in undisturbed conditions and expected after the underground repository creation is not sufficient at present. Modern data on the earth's crust power, on the range and planetary centrifugal direction of the heatmass transfer processes are indicative of the necessity to take into consideration a possible relation of a geologic object to deepseated zones of enclosing large geologic structures; a density of heat flows and an intensity of mass transfer in a section: deep crustal zones → earth's surface (basement → earth's surface -- for sedimentary basins); the resulting effects of interactions of the natural thermal and geochemical fields with analogous artificial formations - products of radioactive element disintegration in the buried waste composition; seismic effects of decreasing the volume of sedimentary rock as a result of their catagenetic transformations in deep-seated zones of sedimentary basins. A project of general classification of geologic megastructures according to conditions of radioactive wastes burial was developed and is discussed. The project is based on a concept of power potential of large geologic structures involving their seismic activity and geologic-geochemical effects of deep heat and mass transfer in the earth's crust upper parts

[en] It has been established that the geochemical and ecological situation in the sites formerly occupied by military bases does not satisfy nature management and living standards. The concentrations of heavy metals (Pb, Zn, Cd, Mo and Cu), oil products and semi-volatile organic compounds in soil and ground which exceed the permissible contamination limits make them dangerous for utilisation and require cleaning up measures

[en] A number of hypotheses have previously been developed concerning the rates of uptake and elimination of radiocaesium (¹³⁷Cs) in fish. These include the influence of potassium and other water chemical parameters on both uptake and elimination, and the effect of fish size on accumulation. In order to test these hypotheses, we have assembled a data set comprising more than 1000 measurements of radiocaesium (¹³⁷Cs) in predatory fish (perch, pike and brown trout) in nine European lakes during the years after Chernobyl. These data have been analysed using simple models for uptake and excretion of ¹³⁷Cs in fish, showing that: - Fish-water concentration factors (CF) were inversely proportional to potassium [K⁺] concentration of the different lakes, in agreement with previous studies. - The uptake rate of ¹³⁷Cs in fish was negatively correlated with lake [K⁺], but excretion rate was independent of [K⁺]. - Lower than expected CF values were found in one lake, Iso Valkjaervi, Finland. This is attributed to inhibition of the K⁺ (and therefore ¹³⁷Cs) high affinity transport system in aquatic plants and fish by low pH and/or low Ca²⁺. - The inclusion of fish weight as a parameter in our dynamic model significantly improves the ability of the model to fit the observed measurements of ¹³⁷Cs. - The model developed from the above hypotheses was able to fit the data from nine different lakes to within approximately a factor of 3 of the observed values

[en] The problem of radioactive waste disposal in the Belarus Republic arose recently in connection with rehabilitation of the areas contaminated after the accident at the Chernobyl NPP. This problem has a number of specific features, as in this case, it does not deal with industrial radioactive waste, the content and properties of which could be controlled or defined at the operation stage of related facilities, but with waste generated as the result of spontaneous uncontrolled transfer and fall out of radioactive substances released from the damaged reactor. These processes have led to the relatively low level of contamination over large areas. The specific character of contamination demands specific approaches to the subject of decontamination and rehabilitation, since appropriate technologies should be simple, effective and inexpensive. A specific approach should be used to the subject of waste management as well, since it would deal with large volumes of very low-level waste

[en] The behaviour of Chernobyl-derived ¹³⁷Cs in a hydrologically isolated bog system in the catchment of the Pripyat River, Belarus was investigated. Measurements were made of ¹³⁷Cs activities in the solids and pore waters of the bog soils, as well as the variability in activity in water draining from the bog. It was found that the radiocaesium activity of the pore water, and hence the measured distribution coefficient, K_d, was dependent upon the pressure at which the water was removed from the soil. Measured values of K_d were of the order 10² l/kg at an extraction pressure of 0.8 MPa, approximately one order of magnitude lower than those measured in a similar system, Devoke Water, in the UK. Results of comparative measurements suggested that this was a result of the different pore water extraction techniques used. The vertical migration of radiocaesium was modelled using a solution of the advection-diffusion equation. Using a mass balance approach, it was estimated that ¹³⁷Cs was removed from the system at a rate of 0.3% of the catchment inventory per year, 8 years after the Chernobyl accident. It was shown that both vertical migration and removal of ¹³⁷Cs is best modelled using a K_d based on a measurement of pore water held at low pressure in the soil, 10³ l/kg. ¹³⁷Cs activities in soil pore waters and in drainage waters were very strongly related to the aqueous potassium concentration, and both showed concentration minima in drainage water during the spring. It was shown that runoff coefficients of radiocaesium from peat bogs 8 years after the Chernobyl accident were approximately one order of magnitude greater than those from unsaturated soils of higher mineral content

[en] Short communication

[en] This paper presents main results of joint studies carried out in frame of EC-coordinated ECP-3 Project 'Modelling and study of the mechanisms of the transfer of radioactive material from the terrestrial ecosystem to and in water bodies around Chernobyl' in part of geochemical pathways. Physico-chemical models of specific migration processes are developed and recommended for application as sub models for inclusion in the decision support system (JSP-1). Main parameters, determining the behaviour of radionuclides in aquatic ecosystems are identified and methods for their estimation in |emergency situations are proposed

[en] Two different models for predicting the time-dependent mobility of ⁹Sr in river systems have been evaluated using post-Chernobyl monitoring data for five large Belarusian rivers (Dnieper, Pripyat, Sozh, Besed and Iput) in the period between 1990 and 2004. The results of model predictions are shown to be in good agreement (within a factor of 5) with the measurements of ⁹Sr activity concentration in river waters over a long period of time after the accident. This verifies the relatively good accuracy of the generalised input parameters of these models which were derived primarily from measurements of ⁹Sr deposited after atmospheric nuclear weapons testing (NWT). For the cases studied here, the simpler AQUASCOPE model performed just as well as the more complex 'Global' model which used GIS-based catchment data as an input. The reasons for this are discussed. Exponential decay equations were also curve-fitted to the data for each river to help assess the uncertainties in the predictive models