Ambient Air Monitoring During MGP Site Remediation


Ameren Services


Pana, IL

CEC Services

  • Ambient Air Monitoring

Owner Objective

Ameren Services operated a substation in a residential area in Pana, Illinois. The substation site was previously a Manufactured Gas Plant (MGP) and coal tar residuals had impacted the site soil. Ameren conducted a voluntary cleanup of the site which included the excavation and removal of contaminated soil from three gas holders and one tar well. Ameren retained CEC to conduct perimeter ambient air monitoring during the remediation activities.

CEC Approach

CEC developed a comprehensive Ambient Air Monitoring Plan (AAMP) and a Quality Assurance Project Plan (QAPP) for this project. During the development of the AAMP CEC employees developed site-specific, risk-based ambient air quality standards based on the project’s expected duration and human health risks from specific CPCs, or contaminants of potential concern, identified for both the surface and subsurface soils. The plan included the determination of airborne concentrations of CPCs using real-time and time-integrated air monitoring techniques.

CEC was responsible for the design, installation, operation, calibration, and maintenance of the air monitoring equipment. The real-time air monitoring included monitoring for volatile organic compounds (VOCs), including benzene-specific analysis using on-site gas chromatography (GC) and a portable dust monitor to measure concentrations of particulate matter less than 10 micron in aerodynamic size (PM10).

CEC established four time-integrated air monitoring stations along the perimeter of the project site. Each station was equipped with sampling equipment designed to collect integrated ambient air samples for VOCs, polynuclear aromatic hydrocarbons (PAHs) and PM10 over 72-hour sampling periods. The use of 72-hour sampling periods dramatically reduced the total number of samples analyzed, thus reducing the overall cost of the ambient air-monitoring program.

CEC was responsible for providing daily air monitoring reports to the remediation contractor and weekly briefings during project meetings. In addition, CEC was responsible for preparing and submitting the results of the air monitoring activities in a final project air monitoring report.