Innovative Model Efficiently Estimates Less Restrictive Soil-to-Groundwater Cleanup Levels
Innovative Model Efficiently Estimates Less Restrictive Soil-to-Groundwater Cleanup Levels
Presented on Monday, March 16, 2015
It is imperative contaminated soil be remediated to prevent migration of contaminants to groundwater. It is likewise imperative to only remediate that volume of soil which in fact can cause groundwater contamination and to conserve limited cleanup budgets. This vadose zone model was developed at the U.S. Department of Energy’s Savannah River Site, for this purpose. The model is designed to meet three objectives: (1) utilization as a detailed waste-site specific model for contaminant fate/transport analysis required under the Comprehensive Environmental Response Compensation and Liability Act and Resource Conservation and Recovery Act; (2) perform an analysis using a numerically uniform method that complies with the rules specified by USEPA and is less restrictive than the generic RSL; (3) minimize professional labor-cost to perform a robust fate/transport analysis. It simultaneously back-calculates a soil-to-groundwater Regional-Screening Level (RSL) and groundwater concentration for analytes on USEPA’s Target Analyte List/Target Compound List (TAL/TCL) plus detailed radionuclide suite-221 analytes in total. The software compares a waste-site soil contaminant concentration to its RSL and determines if the waste-site concentration exceeds the RSL. The software compares waste-site soil contaminant concentrations to calculated non-aqueous phase liquid (NAPL) threshold concentrations in soil media in the simulation. The algorithms in the model are powerful because they can estimate less restrictive (higher) RSLs than the generic RSL equations published by USEPA and still be protective of groundwater. The algorithms simulate realistic conditions using a multi-layered soil column, a site-specific pore-water velocity, hydraulic functions for column layers, depth to groundwater, predicted travel time, first-order radioactive decay, biodegradation, and contaminant re-equilibration in the soil column. The model requires a minimum of easily obtained geotechnical data inputs and will automatically identify problem contaminants using a logic function algorithm. The resulting RSLs are suitable for use as remedial goal options or remedial goals.
Gregory Rucker, B.S., M.S.
Enthalpy Environmental Software and Consulting, LLC, Vero Beach, FL
Gregory G. Rucker established Enthalpy Environmental Software and Consulting LLC in 2014. He retired in 2013 after 23 years as Senior Technical Advisor in Area Closure Projects at Savannah River Nuclear Services Inc. in South Carolina. He received a Bachelor of Science degree from Indiana State University and a Master of Science degree in Environmental Science and Engineering from the University of Kansas. Rucker authored five copyrights on vadose zone and equilibrium modeling software and has also published and presented on these topics at national and international conferences. Two of his models are sold commercially.
