Abstract
The transfer of 137Cs and 85Sr from soil to different plants has been studied in two successive pot field-grown experiments. Five plant species (Oryza Sativa, Tritichum Vulgares, Vicia Faba, Sesamum Orientale and Trifolium Alexandrinum) were grown in pots with sandy clay loam soil contaminated with varying amounts of 137Cs or 85Sr. The absorption of the radioisotopes was measured in different parts of the plants and their activity concentration was significantly increased with increasing radioactivity of both radioisotopes in the soil. The distribution pattern of the total absorbed 137Cs or 85Sr in different plants after soil contamination shows that the shoots of these plants contained the highest percentage of both radionuclides (65.8-73.8% for 137Cs and 77.3-80.7% for 85Sr) followed by roots (16.4-22.4% for 137Cs and 19.5-21.4% for 85Sr) and finally by grains/ seeds (4.9-12.9% for 137Cs and 0.3-1.3% for 85Sr). The transfer factors of 85Sr were higher than those of 137Cs for shoots of the tested plants, and were in the ranges of 2.3x10-2 - 4.8x10-2 and 8.8x10-2 - 2.0x10-1 for 137Cs and 85Sr, respectively. The transfer factors of grains or seeds were significantly lower than those of roots or shoots. Also, the transfer factors of leguminous plants were higher than those of cereal plants. Regarding Trifolium plant, the highest activity concentration of both isotopes was found in the second harvest samples.