The Great Lakes Air Deposition (GLAD) program, which concluded in 2013, was coordinated by the Great Lakes Commission to address the deposition of toxic pollutants to the waters of the Great Lakes region and to promote efforts to reduce such deposition and the resulting adverse impacts on human and wildlife health. For more than two decades the program supported scientific research, and engaged scientific leaders throughout the region to better understand the sources of toxic pollutants, their transport in the environment, their deposition to the Great Lakes basin, and the resulting impacts on human health and the Great Lakes ecosystem.
Reducing input of toxic substances to the lakes and the mitigation of impacts from these substances on human health and wildlife are major priorities for restoration efforts in the Great Lakes basin. Of greatest concern are those chemicals that are persistent in the environment, bioaccumulate as they move up the food chain and are toxic to humans or wildlife (referred to as persistent bioaccumulative toxics or PBTs). Many such chemicals enter Great Lakes waters in substantial amounts through deposition from the atmosphere. Despite much progress, further scientific assessment and technological developments are needed to enable effective management of the problems posed by deposition of toxic substances to the region’s waters. Toward this end, the GLAD Program supported scientific projects to identify and quantify the sources, environmental transport processes, deposition rates, fate and impacts of these chemicals. The program operated with the goal of assisting the Great Lakes states and their partners in forming scientifically sound policies regarding this issue, including regulatory and non-regulatory pollution control and prevention programs.