Water quality and ecosystem health surveillance and monitoring data collected to complete assessments of beneficial use impairments of Areas of Concern (AOCs) and to track the effectiveness of remedial measures and confirm restoration of beneficial uses are included in this dataset. AOCs are geographic areas in the Great Lakes that were identified in the mid-1980s where significant impairment of beneficial uses has occurred as a result of human activities at the local level. Remediating AOCs contributes to the sustainability of local communities and of the Great Lakes region, and is a joint commitment under the Canada-United States Great Lakes Water Quality Agreement (GLWQA).