MSECA’s 2025 Fall Seminar

Presented by Wade Meese, Innovative Environmental Technologies, Inc. & Dan Ombalski, Ellingson – DTD

This presentation introduces a breakthrough in horizontal directional drilling (HDD) technology that enables effective delivery of remediation amendments in previously inaccessible areas, such as beneath buildings, around utilities, and within historical manufacturing sites. Traditional methods relying on vertical or horizontal wells and direct push technology (DPT) have faced challenges with zone isolation and limited site access, particularly since conventional HDD wells cannot isolate treatment zones and often require both entry and exit points. The new HDD-based delivery approach overcomes these limitations, allowing precise, isolated amendment injections in complex site conditions where traditional methods are impractical.

Presented by Bill Brab, PG, AST Environmental, Inc.

An innovative bioremediation project was implemented in Gallatin, Tennessee, to address petroleum contamination seeping from a complex karst system into Town Creek and nearby residential areas. The Tennessee Department of Environment and Conservation partnered with the City of Gallatin to rapidly develop and execute a comprehensive cleanup plan, beginning with a data gap analysis and remedial design characterization that included dye-trace studies, geophysics, rock coring, and high-resolution sampling. While no single primary source was identified, impacts were traced to weathered bedrock and shallow epikarst features, with additional contamination found in adjacent overburden soils. Interim remedial measures involved injecting BOS 200® carbon-based amendments into bedrock and epikarst pathways, as well as treating soils in a nearby field to intercept groundwater migration and support long-term biological treatment. As a result, seep impacts to the creek have been reduced to drinking water criteria, odors in the neighborhood have diminished, and the site has achieved managed closure.

Presented by Jim Depa, Jacob & Hefner Associates

While statistical modeling and 3D visualization technology have become more widely accepted tools on large environmental investigation and remediation projects, they remain under-utilized at smaller sites.  However, continuing advancements in software technology and computing power, as well as the integration of Python scripting language, have made the technology more accessible (and economical) to projects of any size.  Analyses of the resulting 3D statically modeled data can improve remedial design and reduce costs by more accurately estimating the in-situ contaminant mass, simulating the size of an excavation, or by designing an in-situ remediation strategy.

Presented by Sarah Jonker & Adam Richmond, Arcadis

Vapor intrusion (VI) assessments in the U.S. have evolved since the 1990s, supported by a range of tools to address the volatilization to indoor air pathway (VIAP). However, many tools are complex, costly, and not always practical for achieving site closure, particularly as state regulations continue to change. A back-to-basics approach by developing a robust conceptual site model (CSM) from which the fundamental aspects of a VI evaluation can be built upon is essential for assessing the VIAP in a straightforward, timely manner. Key CSM components include site history, geology, hydrogeology, building characteristics, and potential receptors. Further, building specific surveys that identify potential background sources and a thorough chemical inventory aid in the interpretation of sample results. Understanding these factors helps identify data gaps, distinguish between site-related and background contamination, and informs discussions with regulators on sampling adequacy and exposure representation. This foundation enables efficient investigation, targeted sampling, and, when necessary, appropriate building mitigation. Case studies demonstrate that emphasizing a thorough CSM, streamlined data collection, and practical mitigation supports expedited, cost-effective site closure while meeting regulatory expectations.

Presented by Brooklyn Boatright, ERM

Accurate sampling is critical to ensuring mitigation of health risks caused by vapor intrusion (VI), and proper quality assurance/quality control (QA/QC) techniques are essential for ensuring accurate and reliable data. Leak detection plays a vital role in preventing data integrity issues caused by compromised sample collection.

This presentation will explore VI sampling leak detection methods and their associated QA/QC techniques. We will review common VI sampling methods and their typical leak detection approaches, with an emphasis on the strengths and limitations of each technique. Additionally, this presentation will cover QA/QC protocols and VI sampling methodologies which ensure compliance with industry standards.

Presented by Sarah Perkins Geosyntec Consultants

This presentation will discuss termination criteria for vapor intrusion mitigation systems. Mass flux calculations will be introduced as an additional line of evidence to support vapor intrusion mitigation system (VIMS) termination decisions.

Mass flux measures the total mass of a contaminant of concern being diverted by a VIMS. Tracking changes in mass flux over time provides additional insight for determining when a mitigation system may no longer be required to manage vapor intrusion risks within the assessed building.

Presented by Jake Liber, Land Science

This presentation will discuss the reasons why an effective QA/QC process is essential in vapor barrier installations. QA/QC measures are pivotal to the success of a contaminant vapor intrusion mitigation system’s installation to ensure long-term success. There are crucial reasons why implementing QA/QC measures before, during, and after the contaminant vapor barrier installation helps guarantee the efficacy of these systems designed to effectively protect indoor air quality for building occupants.