Preventive radioecological assessment of territory for optimization of monitoring and countermeasures after radiation accidents.

A methodology of a preventive radioecological assessment of the territory has been developed for optimizing post-emergency monitoring and countermeasure implementation in an event of a severe radiation accident. Approaches and main stages of integrated radioecological zoning of the territory are described. An algorithm for the assessment of the potential radioecological criticality (sensitivity) of the area is presented. The proposed approach is validated using data of the dosimetric passportization in Ukraine after the Chernobyl accident for the test site settlements.

[The cradle of the Russian radioecology (to the 50th anniversary of the Kyshtym radiation accident)].

On September 29, 1957, at a nuclear industry facility (Production Association "Mayak"), there was a large radiation accident resulting in the release of radioactive wastes into the environment and the formation of the East-Urals Radioactive Trail (EURT). Within the EURT and there established in 1958 an Experimental Scientific Research Station (ESRS) which came to be known as alma mater of domestic radioecology, various comprehensive long-term investigations had been carried out. The main results of these 50-year investigations have been summarized for a broad range of problems on radionuclide migration in the natural environment and ionizing radiation effects on biota, as well as problems of environmental protection. In addition to the studies of the in situ behavior of released during the accident anthropogenic radionuclides (primarily 90Sr, the main dose-forming radionuclide within the EURT), at the ESRS large experiment have been performed to study migration and biological effects on agricultural plants and animals of man-made radionuclides (especially fresh mixtures of fission products) introduced to the natural environment. Results of ESRS experiments are described on irradiation of natural biogeocenoses from a powerful source of ionizing radiation (1.2 x 10(15) Bq 137Cs). The first unique experience is described of remediation of radioactively contaminated areas with emphasis on agricultural radioecology. The importance of the EURT and ESRS radioecological studies for the development of radioecology as a science is stressed.

[Radioecology as a branch of natural science: some thoughts on the interesting past, intricate and vital present and future prospects].

The paper describes more than a century-old history of radioecology, science which studies radionuclide migration in the environment and ionizing radiation effects on biota. The main stages are identified in the development of this branch of natural science associated with the study of problems of radioactive contamination of the biosphere (global radionuclide fallout after nuclear weapons tests, radiation accidents with the release of radioactive substances to the environment). Currently, the basic imperative of radioecological investigations is the analysis of radioecological aspects of nuclear power engineering (mainly problems of radioactive waste management). Issues are discussed of radiation protection of biota (environment)--the anthropocentric (sanitary-hygienic) and ecocentric approaches. The importance of radioecology is indicated as the most advanced field of ecology in studying anthropogenic effects on the nature.

[Method of quantified complete estimation of soil properties for prediction of radionuclide accumulation by plants]. / Sposob kompleksnoi otsenki svoistv pochvy dlia prognozirovaniia nakopleniia radionuklidov v rasteniiami.

A method is founded on consideration of soil as three-phase system where soil solution reaction (pH), absorbing capacity (E) and content of organic matter (OM) are the main characteristics. The method of complete estimation of soil properties (CESP) for quantified analysis of radionuclide soil-to-plant TF dependence on soil properties is grounded and proposed. The area of an effective section (relative units)2 calculated as an area of the triangle with apexes lying in co-ordinates of normalised vectors pH, E and OM in three-dimensional space for complete estimation is used. It is shown that the dependence of 137Cs TF to various crops on CESP can be approximated by equation of power law.

Self-help countermeasure strategies for populations living within contaminated areas of Belarus, Russia and Ukraine.

Countermeasures have been effectively employed within intensive agricultural systems in areas of the Former Soviet Union (FSU) affected by the Chernobyl accident. However, ingestion doses continue to be elevated in some areas as a result of few foodstuffs which are collected from the wild or produced by the household. Forest fungi and berries, and milk from privately owned cattle are the most notable contributors to 137Cs intakes amongst these foodstuffs. In this paper we consider advice which would help affected populations to both understand the importance of these exposure routes and to reduce their exposure. In addition to the potential radiological benefits, self-help schemes are highly cost-effective and likely to have a positive psychological influence on populations living within contaminated areas of the FSU. Evidence to suggest that the transfer of radiocaesium to cow milk is considerably higher in the FSU than within western Europe and North America is discussed.

Fluxes of radiocaesium in selected rural study sites in Russia and Ukraine.

Food production and food harvesting systems common in the areas contaminated by the Chernobyl accident in Russia and Ukraine can be grouped into three major categories: collective farm produce, private farming produce and foods collected from natural ecosystems. The contribution of each of these sources to radiocaesium intake by people living in rural settlements in the mid 1990s has been estimated at two major study sites, one in each country. The collective farm system provided the smallest contribution (7-14%) to the intake of radiocaesium at both sites. Natural food was the major contributor to intake at the Russian site (83%). Whereas private farm produce was the major contributor (68%) at the Ukrainian study site. The difference between the two sites was mainly because private milk production was stopped at the Russian site due to the contamination in 1986. A retrospective assessment of the situation 1 year after the accident shows that collective farming could have been a minor contributor to radiocaesium intake (8%), whilst private farming would have been the major contributor wherever private milk production and consumption continued. The extent to which inhabitants consume natural foods from forests has a considerable effect on their radiocaesium intake. The comparative importance of food products from natural ecosystems increases with time due to the long effective ecological half-lives of radiocaesium in unimproved pastures and forests. Estimation of the fluxes of radiocaesium from the different production and harvesting systems showed that the contribution from private farming and food harvesting from natural ecosystems may be significant, contributing 14-30% to the total fluxes of radiocaesium from an area even if the quantity of food produced in these systems is small. However, the major contributor to the flux exported from an area was the collective farming system, accounting for about 70-86% of the total.

[Analysis of temperature and radiation-induced effects in model and natural biomembranes using UV-spectroscopy method]. / Issledovanie temperaturnykh i radiatsionno-indutsirovannykh éffektov v model'nykh i prirodnykh biomembranakh metodom uf-spektroskopii.

Effects of low-dose gamma-irradiation (up to 1 R) upon UV absorption spectra of water dispersions of egg yolk lecithin (1:1) and samples of rat liver homogenate were studied. Clearly detectable changes could be observed in the 200-220 nm range already under dose loads of several mGy. Radiation sensitivity was shown to be essentially temperature dependent, being the highest at physiological temperatures.

[Effect of radiation on the structure of model and natural biomembranes using differential scanning calorimetry]. / Issledovanie vliianiia radiatsii na strukturu model'nykh i prirodnykh biomembran metodom differentsial'noi skaniruiushchei kalorimetrii.

A novel method of DSC studies of biomembranes has been proposed, making it possible to investigate the influence of ionizing radiations upon the structure of water dispersions of phospholipids and phospholipid-based systems of natural origin, e.g., rat liver homogenates and erythrocyte ghosts. It is shown that in certain concentration range of the bonded water thermograms obtained are reproducible during heating and cooling cycles and can give information about phase state, supramolecular ordering and radiation sensitivity of the systems under consideration.

Present concept on current water protection and remediation activities for the areas contaminated by the 1986 Chernobyl accident.

The results of radiation monitoring data and migration pathway analysis of water bodies within areas affected by the 1986 Chernobyl accident provide a unique opportunity for decision-makers working in other extensively contaminated regions to optimize their approaches to surface and groundwater protection. Most engineering measures within the Chernobyl 30-km exclusion zone were focused on preventing secondary contamination of surface and groundwater from entering the Pripyat River and the Kiev Reservoir. However, implementation of these measures required huge financial and human resources. Therefore, lessons about post-accidental water protection activities can be learned from the Chernobyl example.

Efficiency of measures aimed at decreasing the contamination of agricultural products in areas contaminated by the Chernobyl NPP accident.

The sequence of agricultural countermeasures taken in the Polessye area of the Ukraine contaminated by radionuclides as a result of the Chernobyl NPP accident is discussed. The efficiency of these countermeasures has been analysed. The concentration of 137Cs in crops has been shown to vary 10-100-fold, depending on the biological features of the plant species and on soil properties. Liming and mineral fertilizing of meadows increase the yield of grass and reduce 137Cs transfer to cows' milk up to 3.5-fold.

Biological effects of radionuclides on plants.

On the basis of analysis of the literature and personal data, principles of dosimetry were determined and an analysis was given of biological effects of radionuclides on plants when administered aerially and by root. A comparison was made of radiosensitivity of barley and dependence of sensitivity on the growth phase of the plant at the time of irradiation with a standard LD50 and UD50. The possibility of using correlated paramaters of bioinformation, such as the sensitivity indicator of evaluation of biological effects caused by small radiation doses, is considered. On the basis of correlations of the data obtained a prognosis is made of the probability of losses in harvest of grains subjected to radionuclides at various periods of development.