The article contains data on radioactive isotopes in natural environments (soils, bottom sediments and vegetation) of the epicenters of the underground nuclear explosions for peaceful purposes (crust seismic sounding) in the Arkhangelsk region. It’s shown that the natural isotopes in the in the North, Arkhangelsk, Russia soil on two periods of measurements are in stable condition, cesium-137 moves down the soil profile, and its activity in the soil and vegetation corresponds to the regional level. The elevated radon concentrations are stated in the soil air of the underground nuclear explosions epicenters.