COMPLIANCE INFO_FILE 7 - Laserfiche WebLink

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Cvapor =H*Cliquid: where, a = bulk density (kg/1), b = volumetric water content within the soil volume (dimensionless), c = volumetric air content within the soil volume (dimensionless), Kd = distribution coefficient (1/kg), and H = Henry's Law constant (dimensionless). Soil physical parameters used in the model include density, soil moisture content, and void ratio (porosity). The soil parameter values used in the model are presented on Table A-2 and are representative values for the soil type present at Tracy Yard. Thus soil vapor concentration can be estimated by Jury Model using average soil VOC concentration and soil physical parameters. For Tracy Yard, average soil concentrations were calculated using site characterization information available on VOC source area. Soil concentrations from borings SB6, MW-14B, TW-2B, TYB 29, TYB30 and TYB 31 were utilized for estimating average VOC concentrations within the target area of dual phase remediation system. Using the Jury Model and soil analytical results from the above borings, concentrations of VOC in vapor were estimated and are provided in Table A-2. Vapor Phase VOC Contribution from Ground Water Contribution of VOC concentration resulting from chemical transfer from ground water to the vapor phase was estimated based on average ground water concentration from recent ground water monitoring data. A flow rate of 75 cubic feet per minute (design capacity of the dual phase system) was used to estimate resulting concentration from volatilization of 90 percent of relevant chemicals to the vapor phase. Table A-3 summarizes calculation for this estimate. Net Vapor Phase VOC Concentration from Soil and Ground Water Net vapor phase VOC concentration resulting from contribution from soil and ground water in Tracy Yard is presented in Table A-2. A-2