Commercial formulations of polychlorinated biphenyls (PCBs) were mixtures of 60 to 90 congeners with different degrees or chlorination and positions of chlorine substituents (ortho, meta, or para). Both the number and positions of chlorines impact biodegradation. In general terms, highly chlorinated PCBs are subject to reductive dechlorination while less heavily chlorinated congeners can be co-metabolized aerobically. Thus, while considered persistent in part due to their hydrophobicity, PCBs can potentially be mineralized through a sequence of anaerobic-aerobic biodegradation.
Molecular evidence has conclusively implicated Dehalococcoides in the reductive dechlorination of PCBs. While dechlorination patterns differ between strains, Dehalococcoides strain CBDB1 extensively dechlorinates the main congeners in Aroclor 1260 to tetra- and trichlorobiphenyls.
Submit samples for CENSUS qPCR to quantify a halorespiring bacteria capable of anaerobic biodegradation of PCBs.