У водных организмов Чернобыльской зоны отчуждения, обитающих в градиенте хронического радиационного воздействия, на протяжении последних 15 лет выявлены дозозависимые эффекты, свидетельствующие о поражении биологических систем на субклеточном, клеточном, органотканевом, организменном и популяционно-видовом уровнях.Для высших водных растений в наиболее загрязненных радионуклидами водоемах установлено снижение устойчивости к поражению паразитическими грибами и беспозвоночными, следствием чего является снижение темпов роста, семенной продуктивности и биомассы растений.Частота хромосомных нарушений в тканях высших водных растений и эмбрионов моллюсков в водоемах Чернобыльской зоны отчуждения многократно превышает уровень спонтанного мутагенеза и может быть проявлением радиационно-индуцированной генетической

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 mu Gy h(-1) and in the reference ones - up to 0.09 mu Gy 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 23%. 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. (C) 2015 Elsevier Ltd. All rights reserved.

The dynamics of the main contaminating radionuclides in the components of aquatic ecosystems within the Chernobyl APP exclusion zone is considered. The possible causes are analyzed for the marked increase in the specific activity of 90Sr in water and hydrobionts of the lakes at the dammed left bank of river Pripyat. Notable is the elevated frequency of chromosomal aberrations in the root meristems of aquatic higher plants (up to 17%) and in the embryonal tissues of gastropod mollusks (up to 27%), alterations in the hematological indices for gastropods, and high infestation of aquatic higher plants by parasitic fungi and gall arthropods in the most radiocontaminated reservoirs.

The cytogenetical effects of long-term irradiation in embryo tissue of gastropod snail (Lymnaea stagnalis L.) as chromosome aberration rate as well as change of structure, level of differentiation, death and cytogenetical stability of hemolymph cell population has been studied. Our researches were carried out during 1998–2007 in water bodies within the Chernobyl Exclusion. The absorbed dose rate for snails from research water bodies within the exclusion zone was registered in the range from 1.8 mGy/year to 3.4 Gy/year. The highest rate was found in snails from lakes, the lowest – from the river ecosystems. Molluscs from the control lakes were characterized by absorbed dose rate about 0.3 mGy/year. The lowest rate of chromosome aberration was determined in molluscs form the control lakes – 1.1–2.0%. The highest rate was found in snails from lake ecosystems – 21–23%. In hemoliph of snails from contaminated lakes of the exclusion zone the quantity of death cells averages 40%, the part of phagocytic cells averages 42% as well as decrease of the young amoebocytes quantity to 10–20.1%. In the control water bodies the part of death cells averages from 2.2 to 5.3% and the quantity of phagocytic was at level 3.0–4.2%. The quantity of young amoebocytes have useful increased here to 79.7–89.6%.