QSARs and PARs for biodegradation of PCBs.

Relationships between the biodegradation rate constants of a number of polychlorinated biphenyls (PCBs) and hydrophobic and electronic structural parameters are compared. There is no simple relationship with octanol-water partition coefficients, indicating that the biodegradation rates of PCBs are probably not determined by their rates of permeation through the bacterial membranes. Biodegradation rate constants correlated much better with both the electronic and hydrophobic properties of the chlorine substituents, which suggests that the reactivity and possibly enzyme binding of PCBs control their biodegradation rates.