ECOLOGICAL-MICROBIOLOGICAL ASSESSMENT OF POLYCHLORINATED BIPHENYL-CONTAMINATED GROUNDS

Abstract

Polychlorinated biphenyls (PCB) are ones of most widespread toxic xenobiotics being resistant to environmental degradation. Recovery of natural ecosystems from PCB contamination is primarily related to activity of microorganisms capable of degrading these compounds. In order to study the bacterial communities of degraders from the PCB-contaminated grounds from the area of the JSC «Middle-Volga Chemical Plant» (the City of Chapaevsk, Samara Region), there was evaluated a number of bacteria-degraders in the grounds; the taxonomic composition of these communities was determined and most efficient bacterial associations degrading the PCB were selected. The ground samples taken from this enterprise territory have shown that the PCB concentration varied within 0.21-1.07 mg/kg. The amount of bacteria-degraders of biphenyl/PCB in the grounds under study was estimated as 4.0x106 - 1.5x107. Meanwhile, with the increase of the PCB concentration in the grounds, there was detected elevated number of bacteria-degraders. It was determined that bacterial degraders were represented by genera Achromobacter, Pseudomonas, Arthrobacter, Microbacterium, Acinetobacter, Bacillus, and Rhodococcus. Bacterial associations of degraders were selected that effectively degraded the PCB commercial mixtures «Delor 103» and «Sovol». These bacterial associations may be used for development of new biotechnologies, for remediation of PCB-contaminated soils and grounds.