This brownfield remediation site presented a risk management challenge to our client due to its location in a dense urban neighborhood with nearby sensitive receptors including a public park. Technical challenges associated with remediating the site and limiting exposure to off-site sensitive receptors included the comingled waste, including former dry-cleaning waste (chlorinated solvents) and former manufactured gas plant (MGP) waste (BTEX). Management challenges included numerous background sources of ambient air pollution in and urban neighborhood.
GZA hired AirLogics to deploy a customized real-time air monitoring system (AirLogcis’ Classic 2.0 system) featuring:
- Photoionization Detector (PID) to measure total volatile organic compounds (Total VOCs)
- Field gas chromatograph (GC) for speciation of VOCs, including chlorinated solvents
- Aeroqual nephelometer
- Meteorological station for weather/wind
The “smart” monitoring system triggered the field GC when the PID reached the pre-programmed Action Levels. This allowed identification of specific airborne compounds. An integrated data management and visualization platform was developed to provide clear communication of data as monitoring was ongoing. Extensive background monitoring was performed to develop a solid baseline for air pollution. GZA made vigilant on and off-site observations when action levels were exceeded to help identify the true source of the detections, which frequently were off-site sources.
Detailed speciation of contaminants helped the remediation engineer understand which contaminants were becoming airborne, making rapid intervention possible when contaminants of concern were identified. Non-site related neighborhood sources were documented when applicable, providing risk management with defensible information relative to on- and off-site sources.