U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Mass Flux


Changes in Contaminant Mass Discharge from DNAPL Source Mass Depletion: Evaluation at Two Field Sites
M.C. Brooks, A.L. Wood, M.D. Annable, K. Hatfield, J. Cho, C. Holbert, P.S.C. Rao, C.G. Enfield, K. Lynch, and R.E. Smith.
Journal of Contaminant Hydrology 102(1-2):140-153(2008).

Changes in contaminant fluxes resulting from aggressive remediation of DNAPL source zones were investigated at Hill AFB, Utah (surfactant flooding), and at Ft. Lewis Military Reservation, Washington (resistive heating). Passive flux meters (PFMs) and a variation of the integral pumping test (IPT) were used to measure fluxes in 10 wells installed along a transect downgradient of the TCE source zone and perpendicular to the mean groundwater flow direction. Contaminant flux measurements made using both PFM and IPT approaches at the 2 sites indicate that TCE mass depletion (>60%) in the source zone through aggressive treatment resulted in substantial (>90%) reduction in TCE mass discharge at the source control plane. Use of either PFM or IPT tests to characterize DNAPL source zone can provide critical data needed for more efficient targeting of aggressive treatment to achieve the desired reduction in source strength. This article explores the changes in mass flux at two sites where aggressive source reduction was done. TCE fluxes were reduced from 76 g/day to 5 g/day at the Hill AFB site, and from ~640 g/day 3 g/day at the Ft. Lewis site.

Integrated Concept for Groundwater Remediation
INCORE, 28 pp, 2003.

This report discusses an approach to site characterization that uses the integrated pumping test method. Five sites are discussed as examples.

Adobe PDF LogoMass and Flux Distributions from DNAPL Zones in Sandy Aquifers
M.A. Guilbeault, B.L. Parker, and J.A. Cherry.
Ground Water 43(1):70-86(2005).

Three sites having sandy aquifers are studied in this paper. The contaminants of concern were PCE and TCE. The authors found that three-quarters of the mass discharge occurred within 5-15% of the plume cross-sectional area. Changes in VOC concentrations varied as much as four orders of magnitude across 30-cm vertical intervals.

Quantification of Mass Fluxes and Natural Attenuation Rates at an Industrial Site with a Limited Monitoring Network: a Case Study (Abstract)
A. Bockelmann, D. Zamfirescu, T. Ptak, P. Grathwohl, and G. Teutsch.
Journal of Contaminant Hydrology 60(1-2):97-121(2003).

The number of available monitoring wells at a contaminated site may be limited by economic or geological considerations, making it more difficult to perform a reliable field investigation and to quantify primary lines of evidence for natural attenuation, like the documentation of a decrease of contaminant mass flux in flow direction. This study reports the results of a groundwater investigation at a former manufactured gas plant in southwest Germany. Due to difficult drilling conditions (coarse glaciofluvial gravel deposits and an anthropogenic fill above the aquifer), only 12 monitoring wells were available for the investigation and localization of the contaminant plume. Based on the sparse set of monitoring wells, field-scale mass fluxes and first-order natural attenuation rate constants of the BTEX constituents and low-molecular-weight PAHs were estimated using a different point scale and a new integral investigation method. Even at a heterogeneous site with a sparse monitoring network, point-scale investigation methods can provide reliable information on field-scale natural attenuation rates, if a dependable flow model or tracer test data is available. Lacking this information, only the integral investigation method presented can yield adequate results for the quantification of contaminant mass fluxes under sparse monitoring conditions.

Adobe PDF LogoReport on Application and Demonstration of Integral Groundwater Investigation Approach
G. Gzyl, K. Kura, G. Kotlarz, T. Ertel, P. Kohout, V. Tornielli, R. Pedron, L. Alberti, and C. Lorenzo.
Central Europe Programme, FOKS (Focus on Key Sources of Environmental Risks), 58 pp, 2011.

Discusses integral pumping test results at four sites with introduction to software developed for IPT.

Additional Information

Benefits of Partial DNAPL Source Removal: Measuring Contaminant Flux Change
M.D. Annable, K. Hatfield, J. Cho, M.C. Brooks, A.L. Wood, C.G. Enfield, C. Holbert, and K. Gorder.
The Fifth International Conference on Remediation of Chlorinated and Recalcitrant Compounds, (Monterey, CA; May 2006): Book of Abstracts. Battelle Press, Columbus, OH. Poster presentation, 2006.

At Hill AFB, two innovative methods for measuring water and contaminant mass flux at a DNAPL site were evaluated after the implementation of surfactant flushing. Ten monitoring wells on approximately 10-ft centers were placed downgradient from the DNAPL source zone. In one technique, a transect of passive flux meters (PFMs) was used to measure TCE mass flux passing through the PFMs before and after the surfactant flood. The meters indicated a reduction in TCE flux of approximately 90%. With the other technique—the integral pumping test method—water was subsequently extracted from the same series of wells, and contaminant concentration/time series was measured in each pumping well effluent. These methods were also compared to mass flux calculated using water quality data from the transect of fully screened wells. The three independent measurement techniques provided comparable results, showing significant contaminant mass flux reduction following remediation.

Adobe PDF LogoDetailed Hydraulic Assessment Using a High-Resolution Piezocone Coupled to the GeoVIS
M.L. Kram, G. Robbins, J. Chau, and A. Bagtzoglou.
ESTCP Project ER-0421, NAVFAC TR-2291-ENV, 360 pp, 2008.

This report discusses the results of a demonstration of a high resolution piezocone to obtain very detailed vertical groundwater flux and hydraulic conductivity data. This level of detail can greatly assist in reducing uncertainty in mass flux calculations.

Estimating Contaminant Mass Discharge: A Field Comparison of the Multilevel Point Measurement
and the Integral Pumping Investigation Approaches and Their Uncertainties (Abstract)

C. Beland-Pelletier, M. Fraser, J. Barker, and T. Ptak.
Journal of Contaminant Hydrology 122(1-4):63-75(2011).

A Field Comparison of BTEX Mass Flow Rates Based on Integral Pumping Tests and
Point Scale Measurements (Abstract)

M. Dietze and P. Dietrich.
Journal of Contaminant Hydrology 122(1-4):1-15(2011).

Adobe PDF LogoA Geostatistical Approach for Quantification of Contaminant Mass Discharge
Uncertainty Using Multi-Level Sampler Measurements

K.B. Li, P. Goovaerts, and L.M. Abriola
Water Resources Research 43:W06436(2007).

Adobe PDF LogoMass and Flux Distributions from DNAPL Zones in Sandy Aquifers
M.A. Guilbeault, B.L. Parker, and J.A. Cherry.
Ground Water 43(1):70-86(2005)

Three sites having sandy aquifers are studied in this paper. The contaminants of concern are PCE and CE. The authors found that three-quarters of the mass discharge occurred within 5-15% of the plume cross-sectional area. Changes in VOC concentrations varied as much as four orders of magnitude across 30-cm vertical intervals.

Adobe PDF LogoA Multistage Multicriteria Spatial Sampling Strategy for Estimating Contaminant Mass Discharge and Its Uncertainty (Abstract)
K.B. Li and L.M. Abriola.
Water Resources Research 45(6):W06407(2009).

Adobe PDF LogoUse and Measurement of Mass Flux and Mass Discharge
Interstate Technology & Regulatory Council (ITRC), Integrated DNAPL Site Strategy Team.
MASSFLUX-1, 154 pp, 2010.

Mass discharge and flux estimates are used to quantify source or plume strength at a given time and location. This report summarizes the concepts underlying mass discharge and flux and their potential applications, and provides case studies (Appendix A) of the uses of these metrics. The text is written for readers having a general understanding of hydrogeology, the movement of chemicals (particularly DNAPL chemicals) in porous media, remediation technologies, and the overall remedial process.

Adobe PDF LogoValidation of Methods to Measure Mass Flux of a Groundwater Contaminant
Hyouk Yoon, Master's thesis, Air Force Inst. of Technology, Wright-Patterson Air Force Base.
AFIT/GES/ENV/06M-08, 62 pp, 2006.

Flux measurements obtained using two methods were compared with known mass fluxes in a meso-scale three-dimensional artificial aquifer. One method, the tandem recirculating well (TRW) method, was applied using two different techniques. One technique is simple and inexpensive, only requiring measurement of heads, while the second technique requires conducting a tracer test. The second method, the integrated pump test (IPT), requires use of one or more pumping and observation wells in various configurations. The results of the experiments in the artificial aquifer show that the most expensive technique, the TRW method using tracers, provides the most accurate results (within 15%). The TRW method that relies on head measurements is very inaccurate, so the technique appears not to be viable for flux measurement. The IPT method, although not as accurate as the TRW method using the tracer technique, does produce relatively accurate results (within 60%). IPT method inaccuracies appear to be due to the fact that the method assumptions were not well-approximated in the artificial aquifer. While measured fluxes consistently underestimated the actual flux by at least 36% and as much as 60%, it appears that errors may be reduced when potential violations of method assumptions are taken into account.

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