γ-Ray Destruction of PCBs in Isooctane and Transformer Oil

The radiolytic degradation of PCBs in air-equilibrated isooctane and transformer oil was investigated. Significant degradation was observed in both solvents studied at moderate absorbed dose. Scavenging studies implicate the electron as the major reactive species responsible for decomposition. This is consistent with what has been observed in neutral 2-propanol; however, surprising differences between the radiolytic behavior of PCBs in polar 2-propanol and nonpolar isooctane are observed. PCB degradation was found to be enhanced in isooctane relative to neutral 2-propanol. Chlorine number and substitution pattern have been found to influence degradation efficiency but to a lesser extent in isooctane than in 2-propanol. Deviations in PCB degradation behavior between isooctane and 2-propanol are interpreted in terms of differences in electron behavior between the two solvents. The products of PCB decomposition appear to be less chlorinated PCBs and PCB−solvent adducts.