Great Lakes Air Deposition Program

About GLAD

The Great Lakes Air Deposition (GLAD) program is coordinated by the Great Lakes Commission to address the deposition of toxic pollutants to the waters of the Great Lakes region and to promote coordinate efforts to reduce such deposition and the resulting adverse impacts on human and wildlife health. The program supports scientific research, information gathering and collaboration among policy makers.

The GLAD program works with 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. By working closely with state, federal, local and international regulators and policy makers, the GLAD program places a large emphasis on promoting scientific efforts that will increase the ability to manage this complicated but urgent environmental issue.

Contamination of the Great Lakes with toxic substances is a well documented problem. For most substances of concern, the major route of entry into the lakes is currently deposition from the atmosphere. Of greatest concern are those chemicals that are persistent in the environment, bioaccumulative as they move up the food chain and are toxic to humans or wildlife. These chemicals are commonly referred to as persistent bioaccumulative toxics (PBTs). Among the list of adverse impacts of these chemicals on humans and wildlife are cancer, immune, reproductive and mental dysfunction, and many others.

Tracing the pathway of these chemicals from emission to atmospheric transport, deposition, distribution throughout the environment, bioaccumulation, exposure and impacts on human health and wildlife is a complicated matter. Formation of scientifically sound environmental management and regulatory programs that ensure protection of the Great Lakes ecosystem and human health from such chemicals is a continuing challenge. The GLAD program supports research projects that are aimed at assisting the Great Lakes states in ensuring such protection.

The Great Lakes are among the most sensitive ecosystems in the world to toxic contaminant deposition and accumulation. Fortunately, the region has also been a world-wide leader in gaining scientific understanding of these threats and forming sound management approaches to mitigate them. In the decades since the inception of the Great Lakes Water Quality Agreement, the Great Lakes Toxic Substance Control Agreement, and the Great Waters Program of the Clean Air Act, a great deal of progress has been made toward understanding the complicated processes of atmospheric deposition and subsequent exposures and impacts. Today, much greater confidence can be placed behind statements concerning the threats posed by these chemicals; the amounts, patterns and sources of their deposition to the lakes; our progress toward removing them; and what further progress can be made.

Nevertheless, further scientific understanding is needed to enable the region to ensure the health of its people, wildlife and natural systems for future generations. The GLAD program pursues such understanding through a suite of projects ranging from monitoring environmental contaminant concentrations and estimating emissions to analyzing trends and source patterns, modeling chemical distribution and assessing impacts. Through the GLAD program, the region's governments, academic institutions and other partners work collectively to further scientifically sound management of atmospheric deposition to the region's water bodies.

The GLAD program helps place the Great Lakes region as a national and world-wide leader in efforts to promote cleaner waters through decreasing inputs from the atmosphere. As many toxic substances travel long distances in the atmosphere, these are truly national and world-wide problems that will require equally broad collaboration and solutions.

View Sponsored Projects
Over the past six years, the program has sponsored more than 35 projects by leading scientists throughout the region. A handful of these are now completed and the results are providing important information to help create better strategies for managing deposition of toxic substances.

Mercury Deposition Monitoring Report
The Great Lakes Commission, working with agency representatives from its member states, has compiled a report detailing the current status of efforts within the Great Lakes region to measure and monitor mercury deposition and making recommendations for further activities needed to better understand and track the deposition of this pollutant, its entry into the Great Lakes food chain, and risk to human and wildlife health.

Download the report
Download the press release

Regional Toxic Air Emissions Inventory
For more than a decade, the eight Great Lakes states and province of Ontario have been working collaboratively to create a high-quality inventory of toxic air emissions within the region. This information is an essential component of the GLAD program, by providing necessary information regarding toxic emissions.

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