Measuring Contaminant MASS Flux/Groundwater Velocity in a Fractured Rock Aquifer Using Passive Flux Meters

The development of cost effective techniques for the assessment and remediation of contaminated fractured rock aquifers has been identified as a science priority in EPA Region 2. This project, funded by EPA’s Regional Applied Research Effort Program, will research the ability of an innovative tool—a passive flux meter (PFM)—to measure groundwater flow velocity and mass flux in a fractured bedrock setting and to compare the results to current technology. The study will be implemented at a Superfund site in Puerto Rico where bedrock aquifers are an important source of drinking water. The goal is to research the ability of a fractured rock PFM (FRPFM) and standard PFM to measure groundwater flow velocity and mass flux in fractures in a fractured bedrock setting and to compare the results to current technology. A PFM consists of a cylinder of activated carbon impregnated with tracer compounds that can be installed in a well screened in unconsolidated deposits to measure groundwater flow velocity and contaminant mass flux. The fractured rock PFM (FRPFM) is an experimental system developed by the University of Florida. In this unit, the activated carbon fabric material of the meter is placed against the bedrock in the borehole wall and uses packers to isolate different sections of the open borehole. Both PFM designs are proposed to be installed in one existing borehole at three or four depths so that the data generated can be compared to information obtained by current technology from this and other boreholes at the site. Use of both PFM designs in the research borehole will allow comparison of the results generated by the different methods.