Remediation of Mercury Contamination Inside an Industrial Facility



Robert L. DeGroot, PG PE
Dr. Michael G. McMurtry, M.D.
STS Consultants, Ltd.
10900 - 73rd Ave. N., Suite 150
Maple Grove, MN 55369-5547

Paula D. Abatie, CHMM
55 Shuman Boulevard
Naperville, IL 60563



This presentation provides an overview of the investigation and remediation of mercury contamination inside industrial facilities that have used elemental mercury in manufacturing processes. A Preliminary Hazard Assessment may be performed to identify human receptors, anticipated contaminant migration pathways (given the building’s design and the history of operations), and the potential exposure pathways of concern based on the current and anticipated future uses of the facility under evaluation. This preliminary assessment helps in preparing a Project Work Plan for the facility investigation, which may include surface wipe sampling, air screening evaluations with a portable mercury vapor analyzer, submittal of indoor air quality samples to a qualified analytical laboratory, and implementation of a Site Safety Plan to protect cleanup contractors and building occupants. Decisions about cleanup depend, in part, on the selection of criteria for determining project completion. These project "closure criteria" may consist of regulatory standards (if available). If regulatory standards are deemed inappropriate for the site, or conditions under evaluation, indoor cleanup criteria may be developed by performing a quantitative health risk assessment. The outcome of the risk assessment may include project-specific closure criteria such as "background" thresholds (using data collected from other buildings) and/or risk-based cleanup goals applicable to various media (i.e., indoor air, building surfaces, etc.). Establishing valid criteria for project closure involves careful consideration of numerous factors (such as property uses, occupancy, potential real-estate transactions, and future liabilities). This process requires input and acceptance from the current owner and the regulatory agency involved.