Contamination of the aboveground parts of plants caused by root uptake and dust particles sedimentation on a surface of plant organs above the ground. The overall aim of the work is evaluate of foliar uptake of radionuclides in plants groves in areas with a high contamination density of soil by the radionuclides.
The studies were performed at the territory of Polessky State Radiation and Ecological Reserve (PSRER). We select Smooth brome grass (Bromus inermis Leyss.) and Wormwood (Artemisia campestris Leyss.) as on objects of study. Resuspension of radionuclides was estimated by deposition on the plates with Petriyanov tissue. Radionuclides washings from the surface of plant were used to estimate a contamination density. Absorbed dose rate of γ- radiation on the soil out the sampling site was 4.3-5.6 µGy•h-1; flux density of α- and β-particles, were: 62-82 and 91-125 pulse•s•cm2 respectively. Density of soil contamination was for Cs-137 – 3.5 MBq•m-2, for Pu-238, Pu-239,240 and Am-241 – 13.4; 29.1 and 82.9 kBq•m-2 respectively.
Resuspension values on sampling sites for Cs-137, Pu-238, Pu-239,240 and Am-241 were 1850, 0.54, 1.91 and 37.2 mBq•m-2 in day respectively.
Ratio of daily fallout activity on plates to soil contamination density was 0.53•10-6, 0.3•10-8, 0.4•10-8 and 0.42•10-6 respectively.
The radionuclides of the Chernobyl outburst of bioavailability for the plants was: Cs-137 > Am-241 > Pu-238 > Pu-239, 240. The specific activity of Cs-137, Pu-238, Pu-239,240 and Am-241 in the aboveground parts B. inermis was 626, 0.15, 0.12 and 0.54 Bq•kg-1. The specific activity of Cs-137, Pu-238, Pu-239,240 and Am-241 in the aboveground parts of A. campestris was: 1002, 0.35, 0.44 and 2.76 Bq•kg-1.
Am-241 and Cs-137 has higher capacity for air transfer than isotopes of plutonium so it causes a significant contribution to the total contamination of plants. The contribution of radionuclides adsorbed on the surface of the aboveground parts of plants in total pollution was 7-13% for Pu isotopes, 11-25% for Am-241 and 1.5-9.2% for Cs-137. Biological features of plants affect the accumulation of radionuclides to plants, and the morphology of plants to the level of surface contamination.