The U.S. Department of Energy-Richland Operations Office (DOE-RL) is making available for informal public review a document describing an approach for using vadose zone (soils under the earth’s surface) models to calculate soil contaminant concentrations protective of groundwater. The document, The Regulatory Basis and Implementation of a Graded Approach to Evaluation of Groundwater Protection, is being issued for informal public review from November 3, 2011 through January 6, 2012.   DOE will consider feedback from interested stakeholders and the public on the planned approach, but no formal response to feedback document will be developed.

The Regulatory Basis and Implementation of a Graded Approach to Evaluation of Groundwater Protection (DOE/RL-2011-50):

• Identifies a regulatory basis for use of fate and transport models for development of screening levels and preliminary remediation goals (PRGs) for contaminants of potential concern (COPCs).
• Establishes a graded approach (GA) for use of vadose flow and transport models that provides for progressively increasing rigor appropriate to the potential risk from a waste site.
• Identifies model parameter values for use in the first steps of the GA when applied to waste sites on the Central Plateau of the Hanford Site.

Please submit feedback by January 6, 2012 to Vadose Zone Modeling@rl.gov.

For additional information or questions, please contact Paula Call (509) 376-8230.

Regulatory Basis and Implementation of a Graded Approach to Evaluation of Groundwater Protection