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3.0 Results of preliminary modeling <br /> Paula Bolio, Fritz Carlson, and David Kinney presented results from preliminary modeling <br /> that was conducted using assumed base input parameters and focused groundwater mixing <br /> cells. The chemicals of potential concern (COPCs) that were modeled were benzene, / <br /> naphthalene (the most mobile non-carcinogenic PNA), and chrysene (the most mobile <br /> carcinogenic PNA). <br /> A table was presented which showed VLEACH results in terms of mass arrival of a chemical <br /> to groundwater per polygon. This table showed that most of the benzene in the soil column <br /> eventually makes it to groundwater in 1000 years, a fraction of the naphthalene in the soil <br /> column makes it to groundwater in 1000 years, and much less than I% of the chrysene in the <br /> soil column arrives at groundwater within 1000 years. In addition, this table showed that <br /> most of the mass of the three chemicals is within the designated source area polygons which <br /> are planned for treatment. <br /> Resulting groundwater mixing cell results were presented for each of the three COPCs <br /> before and after source area treatment (with and without degradation in groundwater) with <br /> respect to the three FS groundwater goals. These plots showed that without source area <br /> treatment some of the groundwater goals will be achieved, even without degradation. <br /> Groundwater concentrations assuming source area treatment, were modeled as being below <br /> the FS groundwater goals. <br /> It was explained that degradation of these chemicals occurs in soil and groundwater and that <br /> these results were only taking into consideration degradation in groundwater. Future work <br /> may incorporate soil degradation as well. <br /> Fritz Carlson presented preliminary results for polygon-specific groundwater concentrations <br /> for certain polygons, illustrating that even small mixing cells with significant mass <br /> contributions of a chemical, result in groundwater concentrations that are within some of the <br /> FS groundwater goals. <br /> 4.0 Future model runs and VLEACH application during FS <br /> Three specific VLEACH model tuns were agreed to at the meeting: <br /> a. A VLEACH run will be conducted with conservative bounds: <br /> - doubling the infiltration rate <br /> - reviewing the site soil data for Foc, volumetric water content, and total <br /> porosity, and using the 95% confidence <br /> b. A VLEACH run will be conducted with an agreed upon base model setup with <br /> the new soil data(from soil borings which were identified at this meeting) included. <br /> 2 <br />