October 10, 2017

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Mary deFlaun and Scott Drew, Article Published in Groundwater

Mary deFlaun and Scott Drew (New Jersey) recently collaborated with several researchers from the U.S. Geological Survey on an article published in the online edition of the journal "Groundwater" on September 5, 2017.

The article is entitled "Bioremediation in Fractured Rock: 2. Mobilization of Chloroethene Compounds from the Rock Matrix." Their co-authors were A.M. Shapiro, C.R. Tiedeman, T.E. Imbrigiotta, D.J. Goode, P.A. Hsieh, P.J. Lacombe, and G.P. Curtis.

The paper is the second of a paired set of papers from the same site. The first paper is entitled "Bioremediation in Fractured Rock: 1. Modeling to Inform Design, Monitoring, and Expectations" The papers detail studies undertaken in the Lockatong mudstone underlying a former Naval Air Warfare Center in West Trenton, New Jersey, where groundwater was contaminated with TCE.

Impact statements are, respectively, "Groundwater flow and solute transport modeling was critical in designing bioremediation in fractured sedimentary rock," and "Chloroethene mobilization from the rock matrix after bioremediation in a sedimentary rock is quantified using groundwater fluxes."

Groundwater is a publication of the National Ground Water Association (NGWA)., NGWA is a community of groundwater professionals working to advance groundwater knowledge and the success of its members through education and outreach; advocacy; cooperation and information exchange; and enhancement of professional practices. The organization's members use their scientific and technical leadership, knowledge, and resources to pursue innovation, model best practices, and improve the business climate for the groundwater industry.


A mass balance is formulated to evaluate the mobilization of chlorinated ethene compounds (CE) from the rock matrix of a fractured mudstone aquifer under pre- and postbioremediation conditions. The analysis relies on a sparse number of monitoring locations and is constrained by a detailed description of the groundwater flow regime. Groundwater flow modeling developed under the site characterization identified groundwater fluxes to formulate the CE mass balance in the rock volume exposed to the injected remediation amendments. Differences in the CE fluxes into and out of the rock volume identify the total CE mobilized from diffusion, desorption, and nonaqueous phase liquid dissolution under pre- and postinjection conditions. The initial CE mass in the rock matrix prior to remediation is estimated using analyses of CE in rock core. The CE mass mobilized per year under preinjection conditions is small relative to the total CE mass in the rock, indicating that current pump-and-treat and natural attenuation conditions are likely to require hundreds of years to achieve groundwater concentrations that meet regulatory guidelines. The postinjection CE mobilization rate increased by approximately an order of magnitude over the 5 years of monitoring after the amendment injection. This rate is likely to decrease and additional remediation applications over several decades would still be needed to reduce CE mass in the rock matrix to levels where groundwater concentrations in fractures achieve regulatory standards.

More Information

Learn more at: https://www.ncbi.nlm.nih.gov/pubmed/28873499.
Learn more about the first article at: https://www.ncbi.nlm.nih.gov/pubmed/28873502.
For consultation regarding Bioremediation in Fractured Rock, contact Mary at This email address is being protected from spambots. You need JavaScript enabled to view it. or Scott at This email address is being protected from spambots. You need JavaScript enabled to view it..
Learn more about Mary at: https://www.geosyntec.com/people/mary-deflaun
Learn more about Scott at: https://www.geosyntec.com/people/scott-drew