The traditional approach for site characterization, which is still in common use today, evolved in the 1980s when contaminant behavior was less understood, analytical methods were being developed, and acceptable analytical quality control could only be achieved using fixed laboratories. With the traditional approach,

  • Multiple steps are typically required to characterize sites
  • Each step requires a separate work plan
  • Each step is often followed by a separate report to the client and regulatory agency
  • Each report starts the agency comment/response cycle
  • The Conceptual Site Model (CSM) is developed over months or years

The high cost of this slow, lengthy process is a deterrent to collecting enough data to accurately characterize sites and developing high-quality CSMs, which are the basis for all ensuing remediation and monitoring decisions. Inadequate, uncertain CSMs can lead to less effective, more expensive remediation or risk management approaches that require more time for site closure and may be less likely to succeed. Advances in field analytical methods, sample collection techniques, and understanding of subsurface contaminant behavior have significantly improved the site-characterization process, leading to alternative approaches that result in more complete CSMs, more effective remediation and risk management, lower project lifecycle costs, and reduced time to site closure.

When appropriate for the client’s objectives, Wilcox Environmental Engineering, Inc. employs Expedited Site Characterization (ESC) as an alternative to the traditional approach. The principles of ESC are:

  • Generating a dense, high-quality set of analytical data in real time by analyzing a large number representative samples in the field to continuously fill data gaps
  • Analyzing site characteristics (e.g., geology, preferential pathways, groundwater conditions) in real time to develop high quality and more accurate CSMs to reduce decision uncertainty
  • Better decisions about exposure pathways and exposure risks, which are the primary drivers of future project costs
  • Improved remediation, risk-management, and monitoring designs, which often translate into more effective, economical, and shorter-term mitigation and remediation.

ESC Advantages

The experiences of Wilcox and the U.S. EPA demonstrate that ESC significantly improves investigation (and ultimately remediation) quality and saves time and cost. Potential cost savings increase with site complexity. ESC advantages and improved cost factors include:

  • Applicable to both small and large sites
  • Fewer work plans, field mobilizations, and investigation reports
  • Lower costs for chemical analyses and reporting
  • Optimization of long-term monitoring locations and costs
  • Lower frequency of, and costs for, regulatory agency interaction
  • Lower costs for agency and third-party oversight
  • Lower project lifecycle costs for site characterization, remediation, and monitoring

ESC Challenges

  • Different approach (comfort level)
  • Overcoming misconceptions and negative bias toward field-generated data
  • Potentially higher costs for early project phases
  • May not be applicable to all sites

IDEM’s Receptivity to ESC

State environmental agencies tend to have a positive view of ESC because it:

  • Produces a large amount of high-quality site-characterization data from which accurate CSMs can be developed
  • Is logical and straightforward and typically reduces the number of interim investigation reports reviewed by the agency