Atmospheric flows of semi-volatile organic pollutants to the Great Lakes estimated by the United States' Integrated Atmospheric Deposition and Canada's Great Lakes Basin Monitoring and Surveillance Networks

Lake Superior Has Lost over 90% of Its Pesticide HCH Load since 1986

“…Periodic reports have documented temporal trends in air concentrations, and atmospheric deposition/volatilization flows of toxic chemicals to and from the lakes. The most recent of these, which updates earlier reports, integrated a 20-year period from the early 1990s to 2012–2013 for air concentrations 4 , 5 and up to 2012–2015 for atmospheric mass flows. 4 , 6 …”

“…The most recent of these, which updates earlier reports, integrated a 20-year period from the early 1990s to 2012–2013 for air concentrations 4 , 5 and up to 2012–2015 for atmospheric mass flows. 4 , 6 …”

“…Inputs came through direct discharge and runoff from the watersheds, but were often dominated by atmospheric deposition, especially for the larger lakes. 1 − 3 The Great Lakes have responded rapidly to declines in atmospheric concentrations of persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), 4 − 6 and burdens in fish have also decreased. 7 − 9 Over time, the lakes have shifted from being net recipients to “secondary sources” of some POPs due to revolatilization from lake water.…”

“… 7 − 9 Over time, the lakes have shifted from being net recipients to “secondary sources” of some POPs due to revolatilization from lake water. 4 , 6 Since the early 1990s, The Canada-U.S. Integrated Atmospheric Deposition Network (IADN) and the Canadian Great Lakes Basin Monitoring and Surveillance Network (GLB) have monitored temporal trends of POPs and other chemicals of emerging concern in Great Lakes air and precipitation.…”

“…Variations in gas exchange direction and magnitude over time depend not only on the temporal trends in POPs atmospheric concentrations but also on their concentrations in lake water. 4 , 6 …”