Estimation of the Lower Threshold Level for Appearance of Genetic Effects in Animals under Chronic Radiation Exposure Using a Method of Non-Parametric Statistics

A database on genetic effects depending on the radiation dose rate (113 records) was collected to quantify the lower threshold for the occurrence of genetic damage in animals under the conditions of chronic irradiation. Analysis of data was performed using a non-parametric statistic method. The lower threshold for genetic effects under chronic technogenic irradiation of animals is 10 mkGy/day; the 95% confidence interval is 3–12 mkGy/day. Despite the fact that the lower thresholds for the manifestation of genetic effects of chronic irradiation differ insignificantly for vertebrate and invertebrate animals, analysis of the entire dataset shows the difference in their radiosensitivity. Dose rate 10 mkGy/day for wildlife animals is not exceeded in situations of normal discharges and emissions from nuclear power plants. The exposure level 10 mkGy/day is exceeded in areas contaminated as a result of past accidents or increased discharges of radionuclides, areas of radioactive waste storage facilities, and uranium mining enterprises; for these cases, more detailed estimations of the radiation dose rates to biota and analysis of uncertainties are required.