Emerging Characterization for Emerging Contaminants: Saturated Soil Sampling and 1,4-Dioxane

Tuesday, August 8, 2017: 1:10 p.m.
Patrick Curry, PG , Arcadis, Novi, MI
Joseph Quinnan, PE, PG , Arcadis, Novi, MI
Jesse Wright, PE, PG , Arcadis U.S., Indianapolis, IN
David Favero, CPG , RACER, Detroit, MI

Detailed characterization of 1,4-dioxane source areas is critical to designing an effective remedy strategy, but most characterization approaches do not provide the resolution required to make informed decisions. When understanding mass distribution and the limitations imposed by hydrostratigraphy are critical, a Smart Characterization approach, such as high-frequency saturated soil sampling, is the best investigation method to support remedy design. Once complete, the high-density dataset can be coupled with soil-water partitioning analysis to estimate the dissolved phase mass present in both the transport zones and storage zones at unparalleled resolution. The difference between groundwater and saturated soil results from co-located samples is diagnostic of plume maturity and the potential presence of residual source mass.

Saturated soil sampling is particularly well suited for evaluating low-permeability source areas where contaminant mass resides in storage zones that cannot be easily characterized with groundwater sampling. The advent of rapid on-site analytical methods for 1,4-dioxane using solid phase micro extraction (SPME) allow for a cost-effective, adaptive approach to source characterization. We recommend completing soil borings on a dense, adaptive grid and using real-time analysis to minimize the number of borings required to meet the objectives of the investigation. Detailed soil logging and geotechnical data collected in parallel with contaminant data provides the hydrostratigraphic context for the analytical results.

These concepts are illustrated for a RACER Trust site located in Michigan where a perched source areas contribute to a deep 1,4-dioxane plume located in weathered bedrock. The Smart characterization approach led to a plume maturity diagnosis revealing the source contained a small percentage of mass relative to the plume, and the distribution of mass at the release point was concentrated in low permeability storage zones. The results demonstrated that remediation was better focused on treating the downgradient plume rather than focused on a depleted source mass.

Patrick Curry, PG, Arcadis, Novi, MI
Patrick Curry, PG, CPG is a Principal Geologist with Arcadis U.S. (Arcadis) in Novi, Michigan. Patrick is the community of practice leader for Smart Characterization for North America.

Joseph Quinnan, PE, PG, Arcadis, Novi, MI
Joe is Arcadis’ global director of site investigations and North American lead for emerging contaminants. He has more than 25 years professional experience in environmental consulting and is co-author of the book Remediation Hydraulics (CRC Press, 2008). He is actively engaged in the development and knowledge transfer of next generation characterization tools including tracer testing methods, DNAPL characterization, LNAPL management, flux assessments, hydrostratigraphy methods and groundwater-surface water interactions. He actively engaged in investigation and remediation projects involving emerging contaminants including bis-chloroethylether, perchlorate, 1,4-dioxane, trichloropropane, and fluorochemicals.

Jesse Wright, PE, PG, Arcadis U.S., Indianapolis, IN
Jesse Wright, PE is a Project Environmental Engineer with Arcadis in Indianapolis, Indiana. Jesse is a core team member of Arcadis’ Smart characterization team and leads the horizontal remediation well practice area

David Favero, CPG, RACER, Detroit, MI
David Favero, CPG, is the Michigan Deputy Clean Up Manager for the Revitalizing Auto Communities Environmental Response (RACER) Trust in Detroit, Michigan. He can be reached at dfavero@racertrust.org.