The migration of volatile organic vapors into existing and future structures (vapor intrusion, or “VI”) from contaminated soil and groundwater can lead to exposures of building occupants to potentially harmful levels of chemicals. Consequently, VI has emerged as a critical driver for investigating and remediating contaminated sites and is increasingly an avenue of inquiry during due diligence assessments for property transfers (Phase I and II environmental assessments). State regulatory agencies, including the Indiana Department of Environmental Management, have placed a high priority on VI as a potentially significant exposure pathway, and the U.S. EPA’s VI guidance to be issued in late 2012 adds substantial importance to this topic.
In response to this market and regulatory impetus, Wilcox has assembled a Vapor Intrusion Practice Team comprised of Technical Director Dr. Jim King, Dr. Chris Bonniwell, Dr. Ajit Joseph, Janna Stathyelich, PE and nationally known VI authority Rod Thompson. These professionals have combined their experience, expertise, and specialized VI training to develop innovative approaches for:
- Establishing “off ramps” or strategies to exit the VI regulatory process,
- Improving conceptual site models when VI is a potential exposure pathway,
- Reducing VI assessment and mitigation/remediation costs, and
- Reducing VI-related liabilities for Wilcox clients.
The behavior of organic vapors in the subsurface and their interaction with man-made structures are not fully understood, which can lead to mischaracterization of the VI exposure pathway. The Wilcox VI team is actively researching subsurface vapor migration and attenuation to improve our understanding of vapor/structure interaction and to develop better conceptual site models that lead to more effective and economical risk assessment, risk management, and remediation.
For example, the Wilcox VI team is developing:
- Low-cost methods for assessing the concentrations of volatile organic compounds (VOCs) in groundwater in the upper portions of source aquifers.
- Methods for extrapolating VI data from one structure to one or more additional structures as an alternative to sampling every structure in the group, each of which represents additional costs and potential liability.
- Methods for economically integrating site-specific meteorological data into VI evaluations to supplement analytical samples and provide more robust VI assessments with fewer samples.
- Strategies for minimizing or modifying the timing of air sampling to reduce potential litigation risks for clients.
- Standard operating procedures (SOPs) for consistent application of emerging field and data-analysis methods.
The Wilcox VI team is also developing Expedited Site Characterization (ESC) approaches for VI and other types of site investigation to maximize client value and reduce costs. The foundations of ESC are:
- More efficient and less expensive site characterizations that generate a high density of high-quality data.
- Higher quality and more accurate conceptual site models that lead to better decisions about exposure pathways and exposure risks.
- Improved remediation, risk-management, and monitoring decisions, which frequently translate into more effective, shorter-term mitigation and remediation and reduced time to site closure.
We would be pleased to have the opportunity to describe our VI experience and services in more detail and with specific application to your site or facility. Please contact any member of the Wilcox VI Practice Team at 317-472-0999.