investigating the inhibitory effect of polychlorinated biphenyls oils (pcbs) on anaerobic biomass by specific methanogenic activity (sma)

background: in this study, the inhibition rate of different oil concentrations containing pcbs (1242 and 1254 pcb arochlors) on the anaerobic biomass was investigated by specific methanogenic activity using the vials with volume of 120 ml. methods: original samples were divided into two groups: with soil containing pcbs and without pcbs and the control samples in both cases were just contained substrate, without adding oil. the concentrations were evaluated in three categories: low, moderate and high values, classified and compared together and with the control samples. findings: the findings of this study indicated that 70% of the cod removal occurred in vials containing only two grams of soil. biodegradation of pcbs containing oil was occurred by microorganisms without any delay in absence of oil containing 0.02 to 0.3 ml pcbs and without using oil containing pcbs. conclusion: maximum specific methane building happened in vials containing 0.1 ml oil. thus optimal concentrations of oil containing pcbs vials that had maximum specific methanognic activity were equal to 0.1 ml with 0.1 ml of acetic acid as auxiliary substrate. and in the 1.5 ml oil input together with the acetic acid as auxiliary substrate the concentration was inhibitor.