Quantifying Mobilization of Chlorinated Ethene Compounds Following Bioaugmentation in a Fractured Mudstone

Tuesday, October 3, 2017: 11:10 a.m.
Allen Shapiro, Ph.D. , U.S. Geological Survey, Reston, VA
Claire R. Tiedeman , National Research Program, U.S. Geological Survey, Menlo Park, CA
Thomas E. Imbrigiotta , New Jersey Water Science Center, U.S. Geological Survey, Lawrenceville, NJ
Daniel J. Goode , Pennsylvania Water Science Center, U.S. Geological Survey, Lawrenceville, NJ
Paul A. Hsieh , National Research Program, U.S. Geological Survey, Menlo Park, CA
Pierre J. Lacombe , New Jersey Water Science Center, U.S. Geological Survey, Lawrenceville, NJ
Mary F. De Flaun , Geosyntec Consultants Inc., Ewing, NJ
Scott R. Drew , Geosyntec Consultants, Ewing, NJ

Remediation technologies are often applied in fractured rock; however, it is challenging to evaluate their effectiveness with sparse monitoring that is typical in these heterogeneous geologic environments. Monitoring geochemistry usually entails boreholes that target individual or closely spaced permeable fractures. However, the primary porosity of the rock (or rock matrix) is likely to retain the majority of contaminant mass due to diffusion from fractures. Monitoring changes in geochemistry in the rock matrix is not economical because of the high cost of collecting rock cores.

This investigation demonstrates that integrating site characterization with groundwater modeling and the strategic location of monitoring boreholes can be used to evaluate the effectiveness of remediation conducted in fractured rock. Bioaugmentation of chlorinated ethene (CE) compounds was conducted in the mudstone underlying the former Naval Air Warfare Center, West Trenton, NJ. Groundwater modeling was used to design locations for monitoring, and the location and injection volume of bioaugmentation amendments. Groundwater fluxes from the model were coupled with CE concentrations from monitoring boreholes to formulate a CE mass balance of the region targeted in the bioaugmentation. Differences in CE fluxes into and out of the rock volume identified the total CE mobilized from diffusion, desorption, and NAPL dissolution under pre- and post-injection conditions. The mobilized CE mass was compared with the initial CE mass in the rock matrix estimated from analyses of rock core conducted prior to the bioaugmentation.

The CE mass mobilized per year prior to the bioaugmentation was small relative to the total CE mass in the rock matrix, indicating that hundreds of years would be needed for current pumping and natural attenuation to achieve remedial objectives. The post-injection CE mobilization rate increased by an order of magnitude, but multiple remediation applications would be needed over decades to reduce CE concentrations to acceptable limits.

Allen Shapiro, Ph.D., U.S. Geological Survey, Reston, VA
Dr. Allen M. Shapiro is a Senior Research Hydrologist with the U.S. Geological Survey in Reston, VA.


Claire R. Tiedeman, National Research Program, U.S. Geological Survey, Menlo Park, CA
Claire Tiedeman is a Research Hydrologist at the U.S. Geological Survey, where her work involves characterizing and modeling flow and transport in fractured rock aquifers, calibrating and evaluating models of complex groundwater flow systems, and developing methods to evaluate prediction uncertainty. She is co-coordinator of USGS research on contaminant transport and remediation at the former Naval Air Warfare Center, and is co-author of the textbook Effective Groundwater Model Calibration: With Analysis of Data, Sensitivities, Predictions, and Uncertainty.


Thomas E. Imbrigiotta, New Jersey Water Science Center, U.S. Geological Survey, Lawrenceville, NJ
Thomas Imbrigiotta is a Hydrologist with the U.S. Geological Survey. His research interests involve tracking changes in groundwater geochemistry in fractured rock chlorinated solvent plumes during remediation, determining sorption and diffusion coefficients of contaminants from the primary porosity of fractured rock, and developing groundwater passive diffusion samplers.


Daniel J. Goode, Pennsylvania Water Science Center, U.S. Geological Survey, Lawrenceville, NJ
Dan Goode is a Research Hydrologist with the U.S. Geological Survey.


Paul A. Hsieh, National Research Program, U.S. Geological Survey, Menlo Park, CA
Paul Hsieh, Ph.D., is a research hydrologist with the U.S. Geological Survey in Menlo Park, California, and is chief of its Hydrology of Fractured Rocks project. His experience includes fluid flow and solute transport in fractured rocks, hydraulic and tracer testing, computer simulation and visualization, groundwater resources in bedrock terrain, poroelasticity analysis of fluid/stress interaction, and subsurface deformation. Among his many distinguished honors, Hsieh served as the NGWREF Darcy Lecturer in 1995 and received NGWA’s John Hem Award in Science & Engineering in 2012.



Pierre J. Lacombe, New Jersey Water Science Center, U.S. Geological Survey, Lawrenceville, NJ
Pierre Lacombe is a supervisory hydrologist with the U.S. Geological Survey.


Mary F. De Flaun, Geosyntec Consultants Inc., Ewing, NJ
Mary de Flaun is a Principal Environmental Scientist with Geosyntec Consultants in Ewing, New Jersey.


Scott R. Drew, Geosyntec Consultants, Ewing, NJ
Scott Drew is a Senior Environmentatl Scientist with Geosyntec Consultants in Ewing, New Jersey.