TRANSFORMATION CHANGES IN THE PROPERTIES OF TECHNOGENIC-SALINE SOILS UNDER CONDITIONS OF HUMID SOIL FORMATION IN THE MIDDLE TAIGA SUBZONE OF WESTERN SIBERIA

Two types of salinization are compared: mineralized Cenomanian waters and crude oil bottom waters in different pollution zones (epicenter, impact zone, boundary). The systematic position of soils was determined according to the Classification and Diagnostics of Soils of Russia (Shishov et al., 2004) and the World Reference Base for Soil Resources (IUSS…, 2022). Contaminated soils are classified as technogenically saline podzolic soils ( Chloridictechnic Salictechnic Gleyic Podzol ) and technogenically saline alluvial soils ( Salictechnic Chloridictechnic Technic Gleyic Fluvisol ). To identify the features of salt accumulation during salinization by mineralized Cenomanian waters and crude oil bottom waters, two soil profiles (P-1, P-2, respectively) were laid in the most transformed zone - the epicenter. Samples were taken along the entire depth of the soil profile. In the epicenter, impact zone, pollution boundary, a number of soil pits are also laid (P-1.1, P-1.2, P-1.3; P-2.1, P-2.2, P-2.3). The sampling depth was 0-10 cm and 10-30 cm. In most cases, oil-contaminated soils are characterized by the sulfate type of salinization with anionic composition and the sodium type of salinization with cationic composition. Toxic salts are represented by NaCl, Na₂SO₄, MgCl₂. For technogenically saline soils, sulfate-chloride and sodium types of salinization are characteristic. Toxic salts are represented by NaHCO₃, Na₂SO₄, MgCl₂. The degree of salinization in both types of pollution varies widely: from weak to strong. In oil-contaminated soils, it was found that an increase in the content of oil products is closely related to an increase in the degree of soil salinization at a reliably significant level ( p < 0.05). A method for restoring technogenically saline soils is proposed, based on measures used in melioration practice (arrangement of a system of drainage trenches, ditches; gypsum application; fertilization). It is advisable to supplement the set of measures with a biological stage of reclamation using salt-tolerant vegetation. In oil production, organochlorine compounds are used as a chemical reagent to increase the recovery of the oil reservoir. Chloride ion (the main component of these reagents) is also an available and good solvent capable of removing paraffin deposits in wells. In this regard, this ion was chosen as the main indicator characterizing the efficiency of the applied reclamation solutions. In subsequent years, monitoring of the dynamics of changes in the content of chloride ions in various areas (background, experimental and control) was carried out. The identified features of changes in the ecological state of soils (development of the process of technogenic halogenesis and processes of technogenic alkalization) should be taken into account when conducting new large-scale pilot industrial tests of new environmental protection measures in the middle taiga subzone of Western Siberia.