The Behaviour of Uranium in Soils and the Mechanisms of Its Accumulation by Agricultural Plants

Abstract

Environmental contamination by 238U occurs in the resting places of rocks with high uranium content in the points, where the ground waters come out on the Earth surface. 238U enters the atmosphere because of volcanic outbursts, forest fires, meteoric dust and soil transfer by the wind. A significant fraction of environmental contamination is formed by the products of 238U leaching from the wastes of uranium mines and plants and releases of uranium fusion (yellow substance) from the stacks of the enterprises processing the uranium concentrate. Entrance into the environment with the wastes of phosphate industry (at phosphate rock processing), application of phosphoric fertilisers (superphosphate, precipitated phosphate and others), coil burning at thermal power plants and primary metal establishments are considered as the intensive source of agrocoenosis contamination. The conducted studies established that the accumulation of 238U by crops is closely related to the content of humus, mobile calcium and physical clay in the soils. The correlation coefficient between the accumulation of 238U in the oats grain and the humus content in the soil is R = 0.91 {\textpm} 0.04. Differences in the accumulation of 238U in plants depend on the texture of sod-podzolic soils and come up to 1.2--1.6 times. The uptake of 238U from sod-podzolic soils to barley is 1.4--3.4 times higher than that of chernozem-type soils with a high content of humus and mobile calcium.