[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.

[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.

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.

[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.

[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.

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.