THE CHOICE OF INDICATORS FOR THE ECOLOGICAL RATIONING OF PETROLEUM PRODUCTS IN CHESTNUT SOILS

Abstract

The response of the microbial community of soils to dif erent levels of oil contamination in a model experiment was studied according to indicators: basal respiration (BR), basal induced respiration (SIR), carbon of microbial biomass (Cmic), potential denitrif cation (DNF), methanogenesis, catalase activity. The soils are represented by light chestnut (Haplic Kastanozems Sodic) and meadow-chestnut (Gleyic Kastanozems Chromic) drysteppe zone of the Stavropol area, dif ering in the organic matter content, salinity and the content of physical clay. The intensity of BR increased af er 30 days of the crude oil input into the soils and caused the growth of Cmic due to the activation of oil-oxidizing microorganisms in anaerobic zones of soils. DNF varied in light chestnut and meadow-chestnut soils not directly, that was probably due to the level of organic matter content in soils and their salinity. Catalase activity was a sensitive indicator for the petroleum hydrocarbons in light chestnut soil, but salinity was the determining factor in its activity in meadow chestnut soil. Biotesting with the use of worms Eisenia fetidashowed the inability of test organisms to survive in non-contaminated chestnut soils. A significant indicator that did not depend on natural factors in chestnut soils was BR and related indicators. Catalase activity and DNF have limitations on the salinity factor.