Characterizing Great Lakes Binational Chemicals of Mutual Concern

The U.S. Environmental Protection Agency’s (EPA’s) Great Lakes National Program Office (GLNPO) plays a key role with Canada in protecting and restoring the Great Lakes Basin Ecosystem, as outlined in the Great Lakes Water Quality Agreement (GLWQA). Annex 3 of the GLWQA focuses on the process for assessing and designating Chemicals of Mutual Concern (CMCs) in the Great Lakes Basin. CMCs are chemicals originating from human sources that both the U.S. and Canada agree are potentially harmful to human health or the environment. GLNPO needed technical support at various stages of the Annex 3 CMC assessment process and selected ERG to provide assistance.

ERG conducted research and analysis to characterize the extent and significance of releases for three candidate CMCs: lead, radionuclides, and polycyclic aromatic hydrocarbons (PAHs). For lead and radionuclides, ERG assisted in developing the initial binational screening assessments. These assessments evaluated the chemicals’ potential risks and relevance to the Great Lakes Basin using a weight-of-evidence approach. For PAHs, a candidate CMC that passed the initial Annex 3 screening assessment, ERG supported development of a more comprehensive Binational Summary Report that provided a deeper evaluation of the potential environmental and human health impacts. Our chemical engineers and scientists supported the assessment processes by:

• Collecting, synthesizing, and analyzing U.S. data on chemical sources and releases to all media, including data from the National Emissions Inventory (NEI), the Toxics Release Inventory (TRI), and a targeted literature review.
• Compiling and evaluating environmental data pertaining to concentrations of contaminants in air, water, sediment, and biota.
• Reviewing literature to determine whether the chemicals are persistent, bioaccumulative, and/or toxic.

Using the compiled data, ERG then answered specific screening questions as part of the binational assessment framework. The completed documents will help inform decision-makers as they determine whether to designate these chemicals as CMCs under the GLWQA.