ИСТИНА

The aim of the research was to evaluate the distribution of La, Ce and Nd in soil components and subsequent effect on absorbtion by plants. For the research we used samples of agro soddy-podzolic soil collected on the experimental field in the Moscow region and Chernozem soil (Kursk region) native soil samples (control) samples of this soil with an extraneous concentration of La, Ce and Nd 10, 20, 50, 100 and 200 mg/kg soil Plant: Oat (Avena sativa L.) and pea (Pisum sativum L.) plants grown on these soil samples according to a standardized method ISO 22030:2005 «Soil quality. Biological methods. Chronic toxicity in higher plants» in four replications. Soils differ in the content of silt fraction, organic carbon, as well as mineralogical composition. Our data indicate that when an excessive amount of one and each of the elements (in our case, La, Ce, Nd) is introduced into the soil in the form of soluble salts, these elements are fixed. The forms of compounds in which these elements are fixed by soils depend on the type of soil, namely, they are determined by the composition and properties of sorbing agents (soil absorbing complex). Comparison of the content and distribution of REE in soddy-podzolic soils and chernozems shows that these soils are fundamentally different in the prevailing fixation mechanisms. In soddy-podzolic soils, energetically weak exchange positions are predominant, associated with exchange sorption on clay minerals and amorphous oxides and hydroxides. In chernozems, the main binding agents are soil organic matter and crystallized nonsilicate minerals containing occluded REEs. In general, there is an obvious difference in the quantitative absorption of lanthanides by representatives of monocotyledonous (oat) and dicotyledonous (pea) plants, which is associated with the peculiarities of their physiology.It has been shown that plant roots absorb 2-3 times more lanthanides than shoots. The minimum amount of lanthanides penetrates into the reproductive organs.The type of soil, namely the type and number of dominant sorption positions characteristic of the soil, is decisive for assessing the degree of possible contamination of plant products with lanthanides.The selectivity of sorption positions to a particular element also plays a role. The need for further research in this direction is obvious.