Genotoxic impact of ionizing radiation at low exposure doses of technogenic radionuclides accumulated in plants

The aim of the work is to generalize the long-term investigation results, determine average values of 137Cs, 90Sr and 239,240Pu activity concentrations in aquatic plants of Ignalina NPP waste water channels and Lake Drukshiai (the cooler of Ignalina NPP); referring to the experimental investigations performed on the test-organism Tradescantia, to evaluate genotoxic impact of low activity concentration 137Cs, 90Sr and 242Pu accumulated in it as well as to compare it with that of Ignalina NPP waste water and water of Lake Drukshiai. The comparison of 137Cs, 90Sr and Pu isotope activity concentrations in aquatic plants and Tradescantia (in the experiment) shows that the lowest value of specific activity of 137Cs and 90Sr in Tradescantia was 100 and 130 Bq/kg d. w., respectively, and the highest value in aquatic plants of Lake Drukshiai was up to 210 and 147 Bq/kg d. w., respectively. The highest value of 242Pu activity concentration in Tradescantia (0.1 Bq/kg d. w.) and the lowest value of 239,240Pu activity concentration in plants of Lake Drukshiai (0.6 Bq/kg d.w.) were of the same order of magnitude. The evaluation of 137Cs, 90Sr and 242Pu internal exposure rate doses in Tradescantia has shown that 242Pu was about 100 times more genotoxic than 90Sr and 137Cs. In the range of investigated Internal exposure doses of 137Cs, 90Sr and 242Pu, which were sufficiently low ((0.5-6.6)*10-6, (3.4-35)*10-6, (0.002-0.01)*10-6 Gy, respectively), the direct dependence 'dose - effect' of Tradescantia somatic mutations has not been determined. (author)