Biodegradation and evaporation of polychlorinated biphenyls (PCBs) in liquid media

Abstract

During microbial degradation of PCBs in a liquid medium, two processes influence the PCB concentration in the medium simultaneously: biodegradation and evaporation. The physical loss of PCB due to evaporation frequently causes false positive results in biodegradation experiments. Therefore, if only PCBs are monitored, the determination of the PCB concentration in both liquid and gaseous phases is necessary for a correct appraisal of biodegradation. The kinetics of PCB evaporation and biodegradation were monitored and described by a simple mathematical model. The evaporation and biodegradation rate constants for individual PCB congeners were determined for PCB degradation in liquid medium byPseudomonas stutzeri andAlcaligenes xylosoxidans, both isolated from a longterm PCB-contaminated soil.