Evaluation of Degradability of Aroclor 1242 by an Aceticlastic Methanogenic Consortium

The rate and extent of degradation of Aroclor 1242 from contaminated surface soil was investigated, using aceticlastic mathanogenic consortia enriched from municipal anaerobic digester. Two different experiments, “intermediate feed” and “starve and feed” were conducted using triplicate 160-mL serum bottle microcosms, containing either 0.1 g, 1 g, 10 g, or 50 g of soil plus 100 mL of the inoculum. The methanogenic consortia in both the experiments were manipulated by feeding them with glacial acetic acid at different time intervals, during 30 days incubation. The fate of Aroclor 1242 in both the experiments was monitored using GC-ECD and GC-MSD analysis. Significant differences were observed between inoculated and uninoculated (control) microcosms, thus suggesting that methanogenic consortium might have been responsible for the degradation of Aroclor 1242. However, GC-MSD results could not confirm that disappearance of PCB was due to anaerobic dehalogenation. Another experiment was performed to evaluate if the removal of Aroclor 1242 was due to its evaporation. It was confirmed that disappearance of Aroclor 1242 was not due to evaporative losses during sample extraction. The actual reason for Aroclor 1242 disappearance from the surface soil microcosms could not be determined from this study.