Environmental Forensics

In 2023, Geo-Logix conducted isotope analysis on a significant TCE (trichloroethylene) groundwater plume at a former solvent recycling facility.

Situation: The site had a complex operational history, including bulk storage, which led to an indeterminate release history. The lateral extent of the TCE plume exceeded expectations for the given hydrogeological setting, prompting suspicions of a commingled plume originating from multiple onsite sources.

Actions:
Forensic isotope analysis, specifically δ13C and δ37Cl isotopic signatures, was instrumental in accurately characterizing the plume. The dual isotope plots clearly distinguished between two separate TCE sources. Plume 1, identified as an older release, exhibited signs of degradation along its axis, while Plume 2, linked to a more recent event, showed no such degradation.
This differentiation was critical in recalibrating plume travel times, revealing that the migration rate was negligible and consistent with the site’s hydrogeology.

Results: The perceived risk to downgradient receptors was significantly reduced from what would have been assumed under a single-plume scenario. The precise isotope forensic work ultimately spared the client from the unnecessary and costly groundwater remediation efforts that would have been based on an overstated risk profile.