Measurement and partitioning of persistent organic pollutants in the environment, application of octanol-air partition coefficients

grantor: University of TorontoThis thesis considers the measurement and partitioning of several classes of persistent organic pollutants (POPs--namely, polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), and polycyclic aromatic hydrocarbons (PAHs). Octanol-air partition coeffcients (KoA) were measured for 18 PCBs, 24 PCNs, and 4 PAHs over a range of environmentally relevant temperatures. The results show that in all cases the value of KoA varied log-linearly with the inverse absolute temperature and that in general, the enthalpy associated with the transition from octanol to air, [Delta]HOA, was similar to the enthalpy of vaporization, [Delta]Hvap. Greater partitioning was observed for coplanar and mono-ortho PCBs. The utility of KOA as a particle-gas partitioning descriptor was tested using results from Chicago air samples. The particle-gas partition coefficient, Kp, was calculated and plotted against KOA and against the subcooled liquid vapor pressure, p°L. Log-log plots of Kp versus P°L showed enrichment for the coplana PCBs and PAHs. This enrichment was resolved by KOA for the coplanar PCBs but only partially resolved for the PAHs. A KoA-based absorption model of particle-gas partitioning was compared with the Junge-Pankow adsorption model. The KOA model provided a better fit for PCBs but not PAHs, which were underestimated. An advantage of the KOA model is that it only requires knowledge KOA and the fraction of organic matter on the particle which are both easily measured. The Chicago field study led to the investigation of a new compound class, PCNs. A method was developed for quantifying PCNs based on the FID response of individual congeners in Halowax 1014, a technical mixture of 2 to 8-Cl congeners. PCNs were quantified in air samples from Chicago and three Arctic locations--a cruise track of the Eastern Arctic Ocean, Alert (Canada), and Dunai Island (Russia). The results show that PCNs contribute significantly to dioxin-type toxicity in air and merit further study. A review is made of the transport processes, concentrations, and implications of organochlorine contamination of the Canadian Arctic. Speculations are made regarding the relationships of global warming, physical chemistry of the compounds, and future trends of contaminants.Ph.D