Technical Guidance for Assessing Remedy Effectiveness, AOC Delisting, and BUI Removal at AOCs and Great Lake Legacy Act
The US-Canada Great Lakes Water Quality Agreement designates Areas of Concern (AOCs) as “geographic areas that fail to meet the general or specific objectives of the agreement where such failure has caused or is likely to cause impairment of beneficial use of the area’s ability to support aquatic life." Since the creation of AOCs in the Great Lakes, 43 sites have been given this designation, including 28 sites in the US. A common thread linking AOCs is contaminated sediments, a legacy of decades of industrial and municipal discharges, combined with sewer overflows, and urban and agricultural non-point source runoff. Although significant progress has occurred in reducing the direct discharge of toxic chemicals, significant residues remain, and pose a risk to aquatic organisms, wildlife and humans.This work will provide technical support and guidance regarding remedy effectiveness, AOC delisting and BUI removal at multiple AOCs in various states of remedial action and planning. The first objective will be to provide data summaries, analysis, and reporting regarding multi-year studies of riparian exposure (and indicators of sediment contamination) at several AOCs. This will result in a series of publications on the use and interpretation of riparian indicators of contamination (e.g., spiders), their utility in remedial action planning (e.g., site characterization and source tracking), and their role in assessing remedy effectiveness at sites that have had extensive sediment remediation. The second objective is to provide data analysis and modeling support to guide future field sampling and remedial planning at AOCs sites that are scheduled for remediation in the near future. Together, these efforts will aid EPA managers in sample plan development and remedial construction (e.g., capping and dredging) that are targeted to specific BUI removals. Our third objective is to provide data analysis and planning for post-remedial remedy effectiveness assessments at AOCs that underwent extensive remedial actions over the last decade.