Borehole diffusive flux apparatus for characterizing diffusive mass-transfer in subsurface systems
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The concept of the Borehole Diffusive Flux Apparatus (BDFA) is presented herein. The BDFA is an innovative apparatus designed to provide continuous direct access to an undisturbed column of sediment that can be monitored at multiple discrete vertical intervals to provide high-resolution characterization of local-scale mass transfer and attenuation. The conceptual basis and technical design of the device are presented, along with an example of borehole design and installation at a field site. Mathematical simulations are used to illustrate its application for two scenarios. The results of these simulations indicate that test periods of several weeks to a few months should be sufficient to obtain robust results. The device has the potential to improve our ability to characterize critical mass-transfer and attenuation processes and to quantify the associated rates. This information is key to the evaluation of remediation alternatives, for enhancing the accuracy of mathematical models, and to support more effective long-term management of large groundwater contaminant plumes present at many sites.
KeywordsGroundwater contamination Back diffusion Attenuation Plume persistence Site characterization
This research was supported by funds provided by the NIEHS Superfund Research Program (P42 ES04940) and the U.S. Air Force. We thank Bill DiGuiseppi formerly of AECOM for his assistance with the field installation. We thank the reviewers for their comments.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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