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.

Ten years of global monitoring under the Stockholm Convention on Persistent Organic Pollutants (POPs): Trends, sources and transport modelling

“…The observed changes over time as reported in these articles are compound specific and demonstrate that the regulatory actions established since the 1980s in some regions and integrated in the global SC framework in 2004 have helped decrease the global concentrations of most older POPs (e.g. Cincinelli et al, 2016;Graf et al, 2016;Hung et al, 2016;Rig et et al, 2016;McGoldrick and Murphy, 2016;Venier et al, 2016;Shunthirasingham et al, 2016;Takazawa et al, 2016), but for some of the newer POPs and chemicals of emerging concern [e.g. per-and polyfluoroalkyl substances (PFASs)], clear temporal trends are still not observed Hung et al, 2016;McGoldrick and Murphy, 2016).…”

“…Camenzuli et al (2016) showed that pesticide concentrations are globally significantly higher in agricultural soil than background soil. Shunthirasingham et al (2016) also reported the highest air concentrations of organochlorine pesticides at an agricultural site compared to two other remote sites in the Great Lakes. These findings reflect the predominantly anthropogenic origin of POPs and their continued emissions from stockpiles, waste-streams and reemission from environmental sinks (e.g.…”

“…Several of the afore-mentioned studies have noted significant differences in air concentrations observed between urban/urbaninfluenced sites and remote locations (de la Torre et al, 2016;Muñoz-Arnanz et al, 2016;Graf et al, 2016;Shunthirasingham et al, 2016). McGoldrick and Murphy (2016) found that concentration patterns of most POPs in fish follow human population densities in the North American Great Lakes Basin.…”

“…Included in this special issue are eight studies featuring measured concentrations and time trends of POPs in air and/or precipitation from key environmental monitoring programs that contribute data to the GMP. These studies present regionally representative or nation-wide results from Greenland , Spain (de la Torre et al, 2016;Muñoz-Arnanz et al, 2016), the United Kingdom (Graf et al, 2016), the Arctic region , the North American Great Lakes region (Shunthirasingham et al, 2016;Venier et al, 2016) and East Asia (Takazawa et al, 2016). There are also four studies that compiled measured concentrations of POPs in media other than air over long periods of time.…”

“…Some of them, especially the PCBs, showed in recent decades slow or no decline in concentrations in various media, e.g. in Great Lakes and Arctic air and precipitation Shunthirasingham et al, 2016;Venier et al, 2016); in air in remote locations in Spain (de la Torre et al, 2016); and in Antarctic Trematomus bernacchii (Cincinelli et al, 2016). These observations reflect that long delays in establishing regulatory measures (e.g.…”