THE CHANGE OF OIL QUANTITY AND DYNAMICS OF SOIL PHYTOTOXICITY AT THE OIL POLLUTION

Abstract

The authors of the article study the regularities of oil quantity change and dynamics of soil phytotoxicity at the oil pollution. The article describes the sequence of study of changes in the amount of pollutant (oil) in the soil. The study was carried out in modeling, laboratory and micro-field experiments. Two types of soils (black soil and turf podzolic soil) were used in the studies. The experiments were carried out in at least three biological and three analytical repetitions. Statistical processing of the results was carried out using Microsoft Office Excel software package.
 The investigation of evaporation of oil from the soil (when the initial concentration of oil in the soil was 10% and the initial moisture of the soil was 20%) shows that the intense evaporation of the liquid composition (oil+water) occurs within the first 12 days and the intensity of evaporation from black soil is higher than from turf podzolic soil.
 The phytotoxicity of oil contaminated turf podzolic and black soils, at different humidity, in the process of natural weathering of oil was determined using such plant test objects as L. usitatissimum, H. annuus, F. vulgare. The significant decrease of phytotoxicity, more than twofold compared with the initial one, lasts up to 45 days. After the 45th day further reduction of phytotoxicity is not observed. After the 45th day even the insignificant growth of phytotoxicity is observed. Obviously, this growth happens due to the formation of more toxic derivatives of oil in the process of natural oxidation.
 It is proved that under natural conditions within the first days there is an intense evaporation of volatile components of oil, which lasts for 45 days in average. At the same time, from 25% to 50% of oil is weathered from the soil depending on its type and the toxicity decreases by 2 approximately. Oil pollution spreads through the profile of the soil and in 6 months, at an initial contamination of 10%, it is observed at a depth of 30-40 cm. The least contaminated is the layer of soil at a depth of 10-20 cm. Therefore, the rehabilitation of soils by phytotherapeutic methods should be carried out 45 days after the pollution, and herbs should be planted at a depth of 10-20 cm.