Mirzoyeva N. The Distribution and migration of Sr-90 in components of the Dnieper River basin and the Black Sea ecosystems after accident on Chernobyl NPP

Subject: water, hydrobionts, bottom sediments. Aim: revealing the regularity of the distribution and migration of Sr-90 after the Chernobyl NPP accident in biotic and abiotic components of the water ecosystems of the Chernobyl NPP pond-cooler, Kievs and Kakhovskoe reservoirs, Northern-Crimean channel and the water area of the Black Sea during 1986-2006, as well as forecasting the time to achieve pre-accident levels of Sr-90 concentration in the components of the researched reservoirs. It is established, that the concentration Sr-90 in water and hydrobionts of the investigated ecosystems decreased, basically, on the order depending on distance of reservoirs from the Chernobyl NPP. It is received, that the Sr-90 concentration change tendencies in water and hydrobionts in time, with a sufficient degree of adequacy, are described by exponential functions. The speeds of the water biogeochemical self-purification flows from after accident Sr-90 are determined, the peculiarity of Sr-90 concentration process by water plants, mussels, fishes from investigated water ecosystems are described. The forecast of time of Sr-90 concentration decrease up to before accident levels in water and hydrobionts from freshwater reservoirs and northwest part of the Black Sea is made. It is appreciated dose commitment on the hydrobionts from investigated water ecosystems.The method of the Black Sea bottom sediments dating on peaks in profiles of Sr-90 vertical distribution is proved.