This presentation deals with an approach to the delineation of the continuing source zone (CSZ).  This process begins in the field where the core is described and the smear zone is located both visually and by taking vapor samples with an organic vapor monitoring device.  The point of doing a three dimensional analysis of the CSZ is to identify and characterize the areas that will constitute a continuing source for chemicals of concern (COCs) in groundwater. There are a number of cases where, due to insufficient knowledge of the vertical and horizontal distribution of the CSZ, systems have been installed and operated for over 3 years and failed due to rebound in COCs caused by movement of groundwater through a partially treated CSZ.  Rebound has constituted an obstacle to achieving cleanup goals on a number sites on which expensive remediation systems have been installed.

This approach can also be enhanced with a computer modeling program.  This would allow a number of possibilities for data analysis and depiction of zones of interest.