Assessment of changes in the biological indicators of brown forest soil when polluted with modern biocides

Abstract

The article is devoted to the actual problem of soil pollution with modern biocides (antibiotics, pesticides). In model laboratory studies, the effect of antibiotic (tylosin) and pesticide (bastion) at concentrations of 1, 10, 100, 1,000 mg/kg on the biochemical properties and microbiocenosis of brown forest soil has been studied. The studies have found negative impact of brown forest soil pollution with biocides resulting in the change of the main microbial and biochemical parameters, indicating the violation of the ecological functions of the soil. The impact of biocides depends on their nature, concentration, and time of exposure. The tylosin antibiotic has stronger inhibitory effect compared with the bastion fungicide. The introduction of low doses of pollutants (1, 10 mg/kg) leads to a slight increase in the abundance of soil microorganisms. Pollution with high doses (100, 1,000 mg/kg) leads to a significant reduction of the abundance of soil microorganisms and enzymatic activity. If polluted with biocides, the environmental conditions (pH) of brown forest soil also change. Enzymes belonging to oxidoreductases class are less resistant to contamination with biocides than hydrolases. The maximum impact of biocides is manifested in the first period after soil pollution (3 days), at subsequent periods there is a tendency to the restoration of biological indicators; however, full recovery (to control values) isn’t observed even 90 days after the pollution.