New model for polychlorinated biphenyls (PCBs)

Who (supervisor): Jay Forrest (Gap Soo Chang)
Venue:  PEGASUS Student Summer Seminar, May 17, 2012.
Abstract: Here we present a new model for the toxicity of polychlorinated biphenyls (PCB).  This model works on a first-principles basis, where it takes into account the basic electronic and electron transfer characteristics of the PCBs, investigated using Density Functional Theory.  The model shows bandgap as the overarching indicator of toxicity, but not the only factor.  Our model explains the why both para- positions are required for high levels of toxicity.  To rank the PCBs on a one-by-one basis, the dipole moment in relation to the most chemically active Cl-sites is critical.  The theory is consistent with accepted the Toxic Equivalency Factor (TEF) model for these molecules, and is also able to improve on it to rank the toxicity of PCBs of similar TEF.  This new model also includes a 13th dioxin-like PCB not under the TEF model, PCB 74.  The model is applied to bandgap measurements of a set of PCBs and the measurements are consistent with the model.  Bandgap measurements also indicate the bio-accumulative nature of PCBs.

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