GROUNDWATER RESOURCES ASSOCIATION
o f C a l i f o r n i a
Presents a 90 Minute GRACast Web Conference
An Approach for Evaluating the Progress
of Natural Attenuation in Groundwater
John T. Wilson, U.S. EPA
Thursday, August 30, 2012
12:00 pm to 1:30 pm Pacific Daylight Time
Early Bird Registration (by August 24) is $50 for Members* and $75 for Non-Members*
Registration after August 24 is $75 for Members* and $100 for Non-Members*
Abstract: Monitored Natural Attenuation (MNA) is widely applied to ground water contamination at hazardous waste sites. Under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), MNA is considered to be a remedy like any other remedy. When MNA has been selected as a remedy, concentrations of contaminants in the groundwater are expected to achieve a clean-up goal at the site within a reasonable time frame. At many CERCLA sites, the time by which the goals are to be obtained is specified in the Record of Decision (ROD). At CERCLA sites, the performance of the remedy or combination of remedies that were selected under the ROD is reviewed every five years. At present, there is no generally accepted approach to evaluate long term monitoring data and establish a time by which clean up goals should be attained. There is also no generally accepted approach that can be used to determine whether the extent of attenuation within a particular five year review period is adequate to allow the site to attain the clean-up goal at the site within a specified time frame.
U.S. EPA recently released a report that addressed these issues [An Approach for Evaluating the Progress of Natural Attenuation in Groundwater EPA 600/R-11/204 www.epa.gov/ada]. The report presents a simple, statistically based approach for evaluating the progress of natural attenuation from the data collected during site characterization and long term monitoring. The report provides an approach to establish the time that should be required to attain the clean up goals, and an approach to evaluate attenuation within a review cycle to determine whether attenuation within that period of time is adequate to allow the site to attain the ultimate clean-up goal by a specified time.
This presentation will review the key aspects of the approach to evaluate MNA as presented in the report, and will illustrate the application of the approach by applying the associated computer applications to example data sets.
This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.
Dr. John Wilson is a research microbiologist with USEPA. He has worked on groundwater issues at the R.S. Kerr Center since 1978. He led the development of the USEPA approach to evaluate Monitored Natural Attenuation of organic contaminants in ground water. His personal research has focused on natural biodegradation of BTEX compounds, ethanol, MTBE, TBA, EDB, and chlorinated solvents in groundwater.
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* This GRACast will use a conference call for audio and WebEx to display the presentation slides. Each registration is allowed access via one phone line and one log in to the WebEx module. More than one person may participate per registration by using a shared computer screen and speaker phone. GRA reserves the right to invoice those individuals and/or organizations that are logged in or connected from telephone numbers that don't correspond to a paid registration.