Statistical evaluation of results of radioactivity monitoring in Mochovce locality

The statistical graphic method is described of cumulative percentage applied to overall statistical evaluation of some results of a study of background radioactivity in the Mochovce locality. It is shown that the radioactivity levels in samples of surface water, aerosols and fallout in the said locality follow the log-normal distribution law. For the said components of the environment, statistical data are given which were ascertained in a study of radioactivity levels in the years 1970 to 1982; the data show a background character. An exception is fallout in 1981 when a radioactive track was found of the Chinese nuclear explosion which was significantly manifested in an increased spread in annual gross beta activity data of one-month samples of atmospheric fallout. The described statistical method is also suitable for overall evaluation of data obtained from monitoring the environs of nuclear power plants with the aim of revealing the local impact of the nuclear power plant on its surroundings or for comparing radioactivity levels with non-nuclear localities. (author)