PARENT SESSION
PT1 - Aquatic Toxicology
Tuesday, 19 November 2002
8:00 AM to 6:30 PM
Exhibit Hall
(P490) Accumulation of americium-241 by phototrophic organisms of the Yenisei River (Russia).
Bolsunovsky, Alexander*,1, Zotina, Tatiana1, Kosinenko, Sergei1, Bondareva, Lydia1, 1 Institute of Biophysics, Siberian Branch of Russian Academy of Sciences, Krasnoyarsk, Russia
ABSTRACT- In Russia, in Zheleznogorsk of the Krasnoyarsk Territory, on the bank of the Yenisei River, is situated the Mining-and-Chemical Combine manufacturing weapons-grade plutonium. The 40-year operation of the Combine has resulted in the contamination of the Yenisei River with artificial radionuclides, including transuranic ones. The aim of our investigation has been to estimate the accumulation of americium-241 by aquatic plants and seston of the Yenisei River in laboratory experiments. The experiments were conducted with the submerged plants typical for the Yenisei River: Elodea canadensis and Fontinalis antipyretica (moss). The diatoms Fragillaria crotonensis Kitt. and Synedra acus Kutz dominated in the total biomass of the phytoplankton samples. In the long-duration laboratory experiments it was determined that the maximum concentration factor of americium-241 for the dry biomass of F. antipyretica is 33000 L/kg and it is more than 10 times larger than the concentration factor for E. canadensis. The experimental investigations of seston samples collected from the Yenisei River showed that americium-241 is largely accumulated by phytoplankton. The contribution of bacterioplankton as well as of the seston fraction smaller than 0.45 
m to the uptake of americium-241 is insignificant. The maximum concentration factor of americium-241 for the dry biomass of microalgae was 345000 L/kg, which is an order of magnitude higher than the concentration factor for the aquatic plants of the Yenisei River. In the course of decomposition, during 30 days the plants lost up to 65% of the americium-241 specific activity accumulated in their biomass.
Key words: aquatic plants, phytoplankton, the Yenisei River, americium-241