UBC Theses and Dissertations
Polybrominated diphenyl ethers in landfills from electronic waste Danon-Schaffer, Monica N.
Previous research on Brominated Flame Retardants (BFRs), including Polybrominated Diphenyl Ethers (PBDEs), has largely focused on their concentrations in the environment and their adverse effects on human health. This thesis explores how these compounds reach the environment, how they are transferred from waste streams to water and soil, and how they are transported to distant locations like Northern Canada. Landfills, which receive a large proportion of society’s discarded consumer waste products, including electronic wastes (e-waste), are the major focus of attention. Leachate was collected and analysed from 27 landfills across southern Canada and 11 dump sites in the Canadian North. There was wide variability in the results, both in terms of the total concentrations of PBDEs and in the distribution of congeners. Northern sites tended to have lower PBDE concentrations than southern ones, but some levels were significant despite the low population density and lack of industry in the north. The North provides a sink for PBDE contaminants. Significant differences in PBDE levels in leachate in contact with wastes originating in different 5-year time intervals suggest that the time-of-manufacture of electronic goods plays an important role in determining the rate of PBDE release into the environment. Electronic components manufactured in the 1985-89 period were found to have especially high PBDE concentrations. Experiments were carried out in which e-waste was contacted with distilled water and leachate from a major urban landfill in a custom-built contactor. There was transfer of PBDEs to the aqueous phase which increased with greater contact time and increasing temperature. Exposing e-waste to distilled water led to lower PBDE concentrations, probably due to dislodgement of fine dust from the surface of e-waste particles. A comprehensive mole balance model was prepared to assist in predicting the concentration of PBDEs in and near landfills. The balances were applied to different homologue groups and different subsystems - field e-waste, non-e-waste solids, and aqueous phase. Mass transfer parameters were obtained from solid-liquid contacting experiments with crushed e-waste. Simulations indicate that PBDEs will persist for decades in the environment even if they are no longer manufactured and incorporated in plastics.
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