Laserfiche WebLink
Human Health Risk Assessment <br /> Former Mobil Oil Bulk Plant 04-343 <br /> 500 East Grant Line Road <br /> • Tracy, California <br /> ?" The wet weight soil moisture content (MWct) is related to the dry wei�lit soil moisture content <br /> according to the following equation: <br /> Mt - 1'Mdy + 1 <br /> Where: Mary = Moisture content by dry weight determination (dimensionless) <br /> ' Mwet = Moisture content by wet weight determination :dimensionless) <br /> The third component of the volatilization model is the calculation of .lux to ground level. The <br /> chemical flux is dependent upon 1) the diffusion coefficient of the chemical, 2) the initial <br /> concentration of the chemical in soil gas, and 3) the depth to contamin,..don. The mathematical <br /> ' model which predicts chemical flux to ground level is presented in the following equation: <br /> ' F - De x Csg <br /> L <br /> ' Where: De = Effective diffusion coefficient of chemical (cm2/ <br /> Csg = Concentration of chemical in soil gas (g/cm') <br /> L = Distance between impacted soil and ground level �--.n) <br /> F = Flux to ground level (g/cm -sec) <br /> 5.3.2.3' 5.3.2.3 Calculation of Indoor Air Chemical Concentration frorr Outside the Building <br /> ' For the current exposure scenario, the site is fenced, unpaved, and undeveloped. Offsite <br /> exposure to toxicant concentrations from contaminated soil onsite will result from the flux <br /> ' through the ground surface and the transport offsite. Ventilation of a building with external air <br /> 30-0136-11 <br /> 5-8 <br />