[Methodology of the approach to express-estimation of radiation risk for public health under the influence of radionuclides present in the ground waters].

The methodological approach for the express-estimation of the value of individual lifetime cancer risk due to the groundwater use by population for drinking is supposed. The calculation of risk is performed with the use of only the values of specific activity of 226Ra in underground water. The formulas for calculating the value of individual lifetime cancer risk in the groundwater use by the population in drinking aims for oral and inhalation routes of exposure are suggested.