Determination of the background content of radionuclides and heavy metals in soil

A comprehensive examination of the soil in the observation zone of the specialized integrated plant MosNPO Radon, which has been operating since 1961, is performed. The content of naturally occurring Ra-226, K-40, and Th-232, technogenic Cs-137, and heavy metals is determined. The soil in the observation zone of an object is classified as "pure" according to the degree of chemical contamination taking account of the danger class of the chemical elements. A recommendation is made for the background content of radionuclides and heavy metals, mainly, in average and heavy loams. Approaches are recommended for making an assessment of the ecological state of the soil in the observation zone of a radiation-dangerous object.