title: Atmospheric concentrations and loadings of organochlorine pesticides and polychlorinated biphenyls in the Canadian Great Lakes Basin (GLB): Spatial and temporal analysis (1992-2012).
abstract: Long-term air monitoring data for POPs are required to determine the effectiveness of source reduction measures and factors controlling air concentrations. Air samples were collected between 1992 and 2012 at three sites with different geographical characteristics (Burnt Island, Egbert and Point Petre) in the Canadian Great Lakes Basin (GLB) using high-volume samplers and analyzed for organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). Spatial and temporal trends of gas-phase concentrations of OCPs, selected PCB congeners and ƩPCBs (84 congeners) were assessed. Egbert had the highest concentrations of some OCPs due to historical [dichlorodiphenyltrichloroethanes (DDTs), dieldrin, γ-hexachlorocyclohexane (γ-HCH)] and current (endosulfan) applications of these pesticides in the surrounding agricultural cropland. This shows that agricultural areas are a source of OCPs to the GLB. High o,p'-/p,p'-DDT ratios were determined and an increasing trend was observed at Point Petre and Burnt Island up to 2004; indicating that the GLB is influenced by dicofol-type DDT sources, which have higher o,p'-/p,p'-DDT ratios than technical DDT. Atmospheric PCB concentrations at Egbert and Point Petre are higher than those measured at Burnt Island, likely due to urban influence and greater populations. Loadings calculations suggest that the atmosphere is a source of α-endosulfan and p,p'-DDT to the lakes and the opposite is true for p,p'-DDE. Long-term decreasing trends were observed for both OCPs and PCBs; consistent with control measures implemented in North America. Atmospheric PCB concentrations are decreasing relatively slowly, with halflives in the range of 9-39 years. Chlordane, α-endosulfan, β-endosulfan, dieldrin, and DDT-related substances showed halflives in the range of 7-13 years. α-HCH and γ-HCH were decreasing rapidly in air, with halflives of 5 years. Long-term declining trends of PCBs and OCPs suggest that regulatory efforts to reduce emissions to the GLB environment have been effective, but emissions from primary and secondary sources might limit future declines.
authors: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St, ON M3H 5T4, Canada.
authors: Chubashini
authors: C
authors: Shunthirasingham
authors: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St, ON M3H 5T4, Canada.
authors: Anya
authors: A
authors: Gawor
authors: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St, ON M3H 5T4, Canada. Electronic address: hayley.hung@canada.ca.
authors: Hayley
authors: H
authors: Hung
authors: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St, ON M3H 5T4, Canada.
authors: Kenneth A
authors: KA
authors: Brice
authors: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St, ON M3H 5T4, Canada.
authors: Ky
authors: K
authors: Su
authors: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St, ON M3H 5T4, Canada.
authors: Nick
authors: N
authors: Alexandrou
authors: Air Quality Processes Research Section, Environment and Climate Change Canada, 6842 Eighth Line, Egbert ON L0L 1N0, Canada.
authors: Helena
authors: H
authors: Dryfhout-Clark
authors: Water Quality Monitoring and Surveillance Division, Environment and Climate Change Canada, 867 Lakeshore Road, Burlington, ON L7R 4A6, Canada.
authors: Sean
authors: S
authors: Backus
authors: National Laboratory for Environmental Testing (NLET), Environment and Climate Change Canada, 867 Lakeshore Road, Burlington, ON L7R 4A6, Canada.
authors: Ed
authors: E
authors: Sverko
authors: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St, ON M3H 5T4, Canada.
authors: Cecilia
authors: C
authors: Shin
authors: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St, ON M3H 5T4, Canada.
authors: Richard
authors: R
authors: Park
authors: Air Quality Processes Research Section, Environment and Climate Change Canada, 4905 Dufferin St, ON M3H 5T4, Canada.
authors: Ronald
authors: R
authors: Noronha
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D002170:Canada; D004784:Environmental Monitoring; D006114:Great Lakes Region; D006843:Hydrocarbons, Chlorinated / Q000032:analysis*; D010575:Pesticides / Q000032:analysis*; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D062211:Spatio-Temporal Analysis; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D011078:Polychlorinated Biphenyls
keywords: Air; Atmospheric loadings; Persistent organic pollutants; Spatial trends; Temporal trends