STATE OF ECOSYSTEMS AT LONG-TERM CONTAMINATION WITH TRANSURANIUM RADIONUCLIDES

摘要

The levels of radioactive contamination with transuranium elements on territory of Belarus as a result of nuclear weapon tests and Chernobyl NPP accident have been assessed by 17 actinides.The study of the atmosphere contamination with TUE in Republic of Belarus is being held since 1980 to now. A gradual decreasing of TUE content in the surface air to 3.2nBq/m~3 in April 1986 as to ~(239-240)Pu. In the period of Chernobyl NPP accident (end of April - beginning of May, 1986) the ~(239-240) Pu content reached value of 120μBq/m~3 in North part of Belarus. The period of half-removal of plutonium from nuclear weapon test and Chernobyl origin from the atmosphere according the observation period is the same and constitutes 14±2 month. The mechanism of radioactive air pollution from April, 1986 is determined by dust transfer from radioactive contaminated regions. The value of this transfer is influenced considerably by agricultural activities on contaminated territory, forest fires and other anthropogenic factors.A characteristic peculiarity of the Chernobyl NPP accident is the injection of small dispersed fuel particles containing TUE into biosphere. The transfer coefficients in the soil- plant system vary from 7.1 × 10~(-6) to 4.0 × 10~(-3) for ~(239+240) Pu and 1.2 × 10~(-5) to 1.4 × 10~(-2) for ~(241) Am and have plant species dependence. The behavior of TUE in environment is discussed.