The textbook consists of two parts: general and special. The general part outlines the basics of two sciences — biogeochemistry proper, which studies the role of living organisms in mass transfer, distribution and redistribution of chemical elements in the Earth's crust, and radiology, the study of radioactivity and radiation. In a special part, the issues of biogeochemistry of the most ecologically significant natural and man-made radioactive chemical elements in the components of the biosphere, and the participation of the biological component in these processes are considered. Special attention is paid to the behavior of artificial radionuclides, environmental pollutants in agroecosystems and their entry into agricultural products. It is intended for undergraduate students studying in agronomic specialties, and employees of environmental and radiological profiles.