engleski

Small-scale field experiment for bioremediation of PCB-contaminated soil

The objective of our study was to propose the method for enhancing PCB degradation in contaminated soil of an transformer station (TS) in Croatia, damaged during warfare operations in 1991. After cycles of microcosm enrichment growth and detailed laboratory biodegradation experiments, the mixed bacterial culture originating from TS contaminated soil (TSZ7) and the isolated member of this mixed culture (Rhodococcus erythropolis strain Z6) were selected as seed cultures for small-scale-field biodegradation experiment. Two strategies have been employed: i) bioaugmentation, (addition of the selected cultures along with soya lecithin, surfactant for enhancing PCB bioavailability ; xylose, supplemental carbon source and carvone, inducer of PCB catabolism), and ii) biostimulation of indigenous soil microflora (addition of soya lecithin, xylose and carvone). Inoculation and amendment was repeated weekly to maintain augmented culture density as well as soil moisture. Soil samples were collected monthly and analysed for the changes in PCB mass fractions by GC/MS. The obtained results suggested that PCB degradation in soil is a slow process when compared to the degradation in liquid media. However, gradual reduction of dominant PCB congeners in TS contaminated soil during 12 month bioaugmentation treatment, is considered a good indication of progressive PCB degradation.

PCB; bioremediation

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