title: From the city to the Lake: loadings of PCBs, PBDEs, PAHs and PCMs from Toronto to Lake Ontario.
abstract: Loadings from Toronto, Canada to Lake Ontario were quantified and major sources and pathways were identified, with the goal of informing opportunities for loading reductions. The contaminants were polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), polycyclic aromatic hydrocarbons (PAHs) and polycyclic musks (PCMs). Loadings were calculated from measured concentrations for three major pathways: atmospheric processes, tributary runoff, and wastewater treatment plant (WWTP) effluents. Although atmospheric deposition to the Great Lakes has received the greatest attention, this was the dominant loading pathway for PCBs only (17 ± 5.3 kg/y or 66% of total loadings). PCB loadings reflected elevated urban PCB air concentrations due to, predominantly, primary emissions. These loadings contribute to consumption advisories for nearshore fish. PBDE loadings to the lake, again from mainly primary emissions, were 48% (9.1 ± 1.3 kg/y) and 42% (8.0 ± 5.7 kg/y) via tributaries and WWTPs, respectively, consistent with emissions deposited and subsequently washed-off of urban surfaces and emissions to the sewage system. PAHs loadings of 1600 ± 280 kg/y (71%) from tributaries were strongly associated with vehicle transportation and impervious surfaces. PCM loadings were 83% (±140 kg/y) from WWTP final effluent, reflecting their use in personal care products. Opportunities for source reduction lie in reducing the current inventories of in-use PCBs and PBDE-containing products, reducing vehicle emissions of PAHs and use of PAHs in the transportation network (e.g., pavement sealants), and improving wastewater treatment technology.
authors.affiliation: Department of Chemical Engineering and Applied Chemistry, University of Toronto , Toronto, Ontario M5S 3E5, Canada.
authors.forename: Lisa
authors.initials: L
authors.lastname: Melymuk
authors.forename: Matthew
authors.initials: M
authors.lastname: Robson
authors.forename: Susan A
authors.initials: SA
authors.lastname: Csiszar
authors.forename: Paul A
authors.initials: PA
authors.lastname: Helm
authors.forename: Georgina
authors.initials: G
authors.lastname: Kaltenecker
authors.forename: Sean
authors.initials: S
authors.lastname: Backus
authors.forename: Lisa
authors.initials: L
authors.lastname: Bradley
authors.forename: Beth
authors.initials: B
authors.lastname: Gilbert
authors.forename: Pierrette
authors.initials: P
authors.lastname: Blanchard
authors.forename: Liisa
authors.initials: L
authors.lastname: Jantunen
authors.forename: Miriam L
authors.initials: ML
authors.lastname: Diamond
mesh_terms: D002170:Canada; D002947:Cities; D004784:Environmental Monitoring; D058735:Environmental Policy; D005229:Fatty Acids, Monounsaturated / Q000032:analysis*; D055768:Halogenated Diphenyl Ethers / Q000032:analysis*; D060106:Lakes / Q000737:chemistry*; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis*; D012722:Sewage
chemical_list: D005229:Fatty Acids, Monounsaturated; D055768:Halogenated Diphenyl Ethers; D011084:Polycyclic Aromatic Hydrocarbons; D012722:Sewage; C008563:musk; D011078:Polychlorinated Biphenyls