Accumulation and distribution of radionuclides in higher aquatic plants during the vegetation period.

The long-term observations of the dynamics of 90Sr and 137Cs concentration, as well as the physicochemical forms of these radionuclides in 10 species of higher aquatic plants during the vegetation period of Glyboke Lake in the Chornobyl Exclusion Zone were presented. The accumulation of radionuclides depends on the influence of environmental factors and species characteristics of the studied plants. It has been shown that the accumulation of 90Sr and 137Cs by plants mainly occurs in accordance with the physiological stages of their development. Under conditions of intensive growth and accumulation of biomass in the juvenile period, plants disproportionately uptake 137Cs from the environment; during the seed ripening period at the stage of aging, plants mainly accumulate 90Sr, as evidenced by the non-correlation of this radionuclide concentration in water and plants in the considered periods. The specific features of the accumulation of radionuclides by plants were studied by the method of analysis of physicochemical forms, which consists in the sequential extraction of radionuclides from plant preparations and makes it possible to quantitatively investigate potentially exchange and fixed forms. The analysis of physicochemical forms confirmed the patterns of seasonal distribution of radionuclides, as well as their accumulation in cells, tissues and in the whole plant obtained from long-term observations.

Radiation-induced cytogenetic and hematologic effects on aquatic biota within the Chernobyl exclusion zone.

During 1998-2014 the rate of chromosomal aberrations in embryo tissues of the pond snail (Lymnaea stagnalis) and root meristems of higher aquatic plants, and also hematologic indexes of mantle liquid of the adult snails and peripheral blood of fishes in water bodies within the Chernobyl exclusion zone (EZ) was studied. The absorbed dose rate for hydrobionts from water bodies of the EZ registered in a range from 0.25 to 420 µGy h(-1) and in the reference ones - up to 0.09 µGy h(-1). The level of chromosomal aberrations in the molluscs from the most contaminated water bodies of the EZ was registered within range of 18-27% and for the molluscs from the reference lakes this index was on the average 1.5% with the maximal values 2.3%. The rate of chromosomal aberrations in root meristematic cells of higher aquatic plants from the contaminated lakes of the EZ was in range of 7-17% and in the plants from reference water bodies was not exceed 2.1%. The positive correlation between chromosomal aberration rate and absorbed dose rate in the pond snail's embryos and root meristems of higher aquatic plants in water bodies of the EZ was registered. Analysis of hemolymph structure of snails from the most contaminated water bodies showed a high rate of dead and phagocytic cells as well as decrease of the young amoebocytes quantity. Hematologic research of fish allows to determine on the one hand an insignificant changes of leukogram structure, and from the other hand a high level of red cells with different abnormalities in the peripheral blood of fishes from the water bodies with high levels of radioactive contamination. It is suppose that qualitative indexes of red cells in peripheral blood of fish are more sensitive to long-term radiation impact in comparison with elements of white blood, which can be used for conducting of the hematologic monitoring of radioactive contaminated water bodies.

[Radioecological problems of aquatic ecosystems of the Chernobyl exclusion zone].

The results of radioactive contamination dynamics in the main components of aquatic ecosystems and the absorbed dose rate for hydrobionts within the Chernobyl accident exclusion zone was analysed. Some cytogenetical and haematological effects of long-term irradiation on aquatic organisms as well as damage of higher aquatic plants by parasitic fungi and gall-producing arthropods were considered.

[Radioecological studies of freshwater mollusks in the Chernobyl accident exclusion zone].

Species-specificity and dynamics of 90Sr, 137Cs and some transuranic elements accumulation in bivalve and gastropod freshwater molluscs of the Chernobyl exclusion zone during 1997-2008 was analyzed. The results of radiation dose and chromosome aberration rate estimation and the analysis of hemolymph composition of freshwater snail (Lymnaea stagnalis L.) was produced. The absorbed dose rate was registered in the range of 0.3-85.0 microGy/h. In closed water bodies the heightened chromosome aberration rate (up to 27%) in embryo tissues, and also the change of haematological indexes for the adult individuals of snails was registered.

[The main radionuclides and dose formation in fish of the Chernobyl NPP exclusion zone].

The results of the researches of spices-specificity, accumulation dynamics and distribution of 90Sr, of 137Cs and of transuranic elements in fish of the Chernobyl NPP exclusion zone are analysed. The data of estimations of absorbed doze rate from incorporated radionuclides for pray fish and predatory species are given. For the fish from the lake of the left-bank floodplain of the Pripyat River the increase of 90Sr specific activity is registered which is presumably connected with the dynamics of the physical-chemical forms of the radionuclide in soils and their wash out in water bodies from the catchment basin. Now about 90% of internal dose rate of fish from closed aquatic ecosystems within the Chernobyl NPP exclusion zone is caused by 90Sr incorporation.

[90Sr, 137Cs, 238Pu, 239+240Pu, and 241Am radionuclides in macrophytes within the Krasnensky flood plain: species specificity of concentration and distribution in phytocenosis components]. / Radionuklidy 90Sr, 137Cs, 238Pu, 239+240Pu i 241Am v makrofitakh Krasnenskoi poimy: vidospetsifichnost' kontsentrirovaniia i raspredelenie v komponentakh fitotsenoza.

The analysis of the content of radionuclides 90Sr, 137Cs, 238Pu, 239 + 240Pu and 241Am in water vegetation of flood plain reservoirs has allowed studing features of radionuclide accumulation by various species of macrophytes and revealing bioindicators of radionuclide contamination. Thus species-specificity of radionuclide accumulation can essentially change the contribution of different species to a percentage ratio of the radionuclide content in phytomass of reservoirs in comparison with fund of higher aquatic plants.

[Functional-ecological and age-specific regularities in radionuclide concentration in freshwater molluscs from the Chernobyl Atomic Energy Station exclusion zone]. / Funktsional'no-ékologicheskie i vozrastnye zakonomernosti kontsentrirovaniia radionuklidov presnovodnymi molliuskami zony otchuzhdeniia Chernobyl'skoi AES.

The results of the studies on 90Sr and 137Cs content in the tissues of bivalve and gastropod mollusks of water basins in the exclusion zone of the Chernobyl NPP have been analyzed. The dependence of radionuclide accumulation factors on the peculiarities of morphological structure, functional ecology and nutrition type was found. The age dynamics of 137Cs content in some species of Gastropoda was studied.

[90Sr and 137Cs in higher aquatic plants of the Chernobyl nuclear plant exlusion zone]]. / 90Sr and 137Cs v vysshykh vodnykh rasteniiakh zony otchuzhdeniia Chernobyl'skoi AES.

The content of radionuclides 90Sr and 137Cs in higher aquatic plants of water objects within Chernobyl NPP exclusion zone has been analysed. Biodiversity of phytocenose was studied and species-indicators of radioactive contamination were revealed. The seasonal dynamics of radionuclide content in macrophytes was studied and the role of main aquatic plant clumps in processes of 137Cs and 90Sr distribution in abiotic component of biohydrocenose was demonstrated.

[Surgical treatment of patients with chronic critical ischemia of legs, caused by atherosclerosis]. / Khirurgicheskoe lechenie bol'nykh s khronicheskoi kriticheskoi ishemiei nizhnikh konechnostei ateroskleroticheskoi etiologii.

208 patients with primary chronic critical ischemia of lower extremities (CCILE) were operated on from 1988 to 1995. The criteria of CCILE were the following: ischemia of an extremity in rest with specific ischemic pain for more than 2 weeks; existence of ulcernecrotic changes in distal parts of the extremity; brachiommalleous index (BMI) less than 0.35; malleous systolic pressure less than 50 mm Hg. Functional condition of the patients corresponded to class 3A, B and 4. The share of patients with CCILE among patients with lower extremities arterial lesions was 35%. In 150 (72%) of them there were lesions of aorto-illo-femoral-tibio-popliteal segment; in 58 (28%)-damage of a femoral-popliteal-tibial segment. The number of patients with trophic changes appear in early stage. 154 reconstructive operations have been performed in patients with multiple arterial lesions higher and lower of the Poupart's ligament, and only one primary amputation and sympathectomy. In 63 (42%) of the patients the "two-floor" reconstruction has been performed. In 142 (92%) of the cases positive results have been achieved. In 78.5% cases the grafts were competent a year after the surgery and the extremities were saved in 88% of the patients. 60 reconstructive operations, 3 primary amputations and 1 sympathectomy have been performed in patients with the lesions, located lower than Poupart's ligament. In 58 (96%) of the patients positive results were achieved. One year after surgery the grafts patency was 63.5%, and extremities were saved in 79% of the patients. The immediate and long-term follow-up results of femoral-politeal and femoral-tibial grafting did not differ significantly. Long-term follow-up results were better in case of less duration of CCILE before surgery. Adequate revascularisation of the extremity is an optimal method of treatment of patients with CCILE.