Articles

The article provides an overview of the results of long-term studies of the migration of radionuclides in the composition of lysimetric waters. The features of lysimetric studies at various stages of radioecology development are considered. It is noted that the use of lysimeters for a long time was limited to low levels of radionuclides in soil solutions, and large-scale studies began after the Chernobyl fallout (1986). It is shown that the greatest output of radionuclides in lysimetric waters occurs in forest, especially coniferous phytocenoses, the least — in meadow and agrophytocenoses. In the long-term dynamics, the maximum intensity of radionuclide migration in the lysimetric waters is observed in the initial period after aerial precipitation, in the seasonal period — in the summer. A small amount of radionuclides migrates with downward water flow. Annual outflow with vertical subsurface runoff varies depending on soil-climatic conditions, the period after precipitation, the thickness and depth of the layer. Annual outflow from the forest litter layer varies from tenths to units of percentage, from the layer 0–20 cm — from hundredths to tenths of a percentage from the total radionuclide supply in these layers. The relative output of ⁹⁰Sr is much bigger than ¹³⁷Cs. In soil solution from 70% to 90% radionuclides [¹⁴⁴Ce, ²³⁹Pu ¹⁰⁶Ru ,¹³⁷Cs and ⁹⁰Sr] are in the form of radionuclide-organic compounds of various molecular weights. 

We studied the ecological state of the soils of the seven most visited recreational areas located throughout Moscow: Losinyi Ostrov, Park Pobedy, Ostankino, Sokolniki, Izmailovo, Kuzminki-Lublino, and Tsaritsyno. Soil samples were collected in summer of 2018 at three sites in each park. The concentrations of 38 chemical elements (Na, Si, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Mo, Sb , Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Tm, Yb, Hf, W, Au, Th, U, Cd, Pb and Cu) in soil samples were determined using neutron activation analysis and atomic absorption  spectrometry. We made the sanitary-hygienic and ecological-geochemical assessment of soils samples and identified slight exceedances of approximate permissible concentration by elements belonging to the first hazard class (As, Cd, Zn). Also, we calculated the total pollution index. The moderately soil pollution by elements belonging first and third danger class was found in the territory of the following parks: Sokolniki, Izmailovo and Park Pobedy. The total pollution index calculated using all trace elements indicated that 50% of the sites belonged to the dangerous pollutionies. Sb, Th, Tb, Cs, and Hf significantly contributed to the total pollution. The highest pollution indices were found in soils samples collected on the territory of the Eastern administrative district in Sokolniki and Izmailovo parks.

In Russia, the lands with oil contaminated soils exceed tens of thousands hectares. However, to date, there were no unified approaches to the rationing of oil and petroleum hydrocarbons (PH) in soils, a guideline to choose optimal evaluation indicators. The response of plants in the pot experiment could provide significant results for assessing and rationing of PH content in soils and their use in agriculture after land remediation. In this work we assessed the response of higher plants as a marker of the direction and intensity of biological processes in soils in the pot experiment under oil contamination to justify the standards of permissible residual content of PH in soils of agricultural lands. The composition and properties of Luvic Chernozems, Calcic Chernozems, Voronic Chernozems (WRB, 2015) used in the pot experiment, which was carried out in a month after the soil contamination with crude sulfur-containing oil, were investigated. The effect of different oil doses on the bioproductivity of wheat and peas was evaluated. Wheat in terms of dry biomass showed higher sensitivity to PH, containing medium and heavy fractions, than peas. Rationing the PH content in chernozems, a nonlinear regression model described by a logistic curve was applied. The quality standard values found for wheat biomass was 0,9; 0,4; 1,0 g * kg^-1 for Luvic Сhernozems (humus content ~ 9,8%, sandyloam texture); Calcic Chernozems (humus content ~7,6%, clay loam texture), Voronic Chernozems (humus content ~12.8%, loam texture), respectively. The residual PH contents, found as 30% of soil functioning change, which corresponded to the risk level of soil degradation, estimated by the soil fertility parameter — dry wheat biomass were 1,2 g·kg^-1 for Voronic Chernozems; 0,5 g·kg^-1 — Calcic Chernozems; 1,1 g·kg^-1 in Luvic Chernozems.

New indicators of lanthanide affinity for carrier phases in the soil, based on the rationing of lanthanide concentrations by their soil clarks, are proposed. This made it possible to obtain an original indicator of the affinity of lanthanide A_LN to carrier phases in soils. The indicator of affinity of lanthanide A_LN showed its advantage over the accepted pC_Ln index in the analysis of Russian and Swedish soils.

Salt neoformations in sandy and silty loam soils of the Aral Sea dried bottom in the south-western part were studied by X-ray fluorescence, electron microscopic, sedimentation methods of analysis and laser diffractometry. The surface layers of soils are significantly saline and enriched with CaCO₃. The distribution of CaCO₃ over the area is quite uniform, which indicates relatively close conditions of its formation during desiccation. The salt content varies from 0.4 to 1.2% in sands and from 3.1 to 5.8% in silty loam. The latter are characterized by the highest salinity, when, in addition to gypsum and halite, readily soluble salts are formed: eugsterite (2Na₂SO₄^.CaSO₄.2H₂O), astrakhanite (Na₂SO₄^.MgSO₄^.4H₂O), and mirabilite (Na₂SO₄^.10H₂O). Precipitation of calcite upon drying leads to the formation of CaCO₃-ooids in sands and CaCO₃- microaggregates from clay and silty particle in silty loam. The reason for the increased activity of easily soluble salts in the processes of aeolian transport has been established. This transport and, correspondingly, the salinization of adjacent territories are facilitated by the blocking of adsorption centers in clays by calcite, which prevents the binding of easily soluble salts in clay-salt microaggregates.

We present a review of the literature data and the results of our own studies on the influence of soil invertebrates of the macrofauna size class on the processes of creating and maintaining the heterogeneity of soil properties in the temperate zone. Significant changes in physical, chemical and biological parameters of soils, compared with background indicators, were noted in excrement and associated soil aggregates, as well as substrates — products of vital activity of key groups of large invertebrates, such as earthworms, diplopod millipedes, diptera and coleoptera larvae, woodlice, and ants. Most of the research is related to the impact of earthworms and ants on soils, whereas for other groups few reports exist. The results of the research will be useful for practical purposes, in particular for the development of sustainable anthropogenic ecosystems.

Methodological aspects of identification, accounting, analysis of development and interaction of soil heterogeneities of various genesis are considered. The modern views on their origin are summarized, methodigical approaches and features of the study are shown. Conceptual views in the field of soil science are presented, which allow a deeper and more comprehensive approach to the assessment of such a phenomenon as soil heterogeneity: the hierarchical orga- nization of soil space, historical and modern («soil-memory» and «soil-moment») components of soil heterogeneity, soil succession and their role in understanding the essence of the phenomenon under consideration. The concept of primary and secondary heterogeneities is formulated, which are defined as a universal feature that manifests itself at all levels of the organization of the soil space and is formed, respectively, by paleo- and cenotic mechanisms. It is shown that the primary heterogeneity is the result of the action of pedogenesis factors, which reflects the desire of the soil to find an equilibrium state with the environment. Secondary heterogeneity is a consequence of the action of various natural and anthropogenic factors that bring the soil system out of equilibrium. A scheme of factors and causes of primary and secondary heterogeneities is proposed and formalized, as well as a scheme of modern factors and causes leading to the emergence of secondary heterogeneity of various origins. The priority role of the works of E.A. Dmitriev and his school in the formation of modern views on the heterogeneity of soils, in the development of field and statistical methods for analyzing the assessment of this natural phenomenon, which he put in a number of direct objects of research, is emphasized.