EFFECT OF BIOREMEDIATION ON GENOTOXICITY OF SOIL CONTAMINATED WITH DIESEL OIL

Soil contaminated with diesel oil was made subject to bioremediation conducted in field lysimeters. After 22 weeks the efficiency of the process exceeded 99%. The mutagenic and carcinogenic properties of the soil contaminants were analyzed using the results of the Ames test. The study has produced the following findings. The soil extracts exhibited mutagenic and carcinogenic properties not only immediately after contamination with diesel oil (10 wt.%), but also upon termination of the bioremediation process. The bioremediation process reduced the mutagenicity of the soil. With the exception of particularly sensitive strain of the YG series, the extracts from the bioremediated soil did not increase the number of revertants of the strain of Salmonella typhimurium TA 98. Seemingly, upon bioremediation the soil contained either nitro derivatives of organic compounds or any other compounds that are formed during biodegradation of diesel oil. The extracts from bioremediated soil contained compounds requiting and non-requiring metabolic activation. Mutagenic substances were present in the dichloromethane extract from soil alone. Being absent in the water extract, they were not subject to leaching and in consequence posed no ecological hazard.