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Table E-1. Groundwater Screening Levels <br /> for Evaluation of Potential Vapor Intrusion Concerns <br /> (volatile chemicals only) <br /> Residential Commercial/]nd ustrial <br /> Land Use Land Use <br /> Physical <br /> Chemical State (pg/L) (pg/L) <br /> Toluene V L 3.8E+05 5.3E+05 <br /> Toxaphene NV S <br /> PH(gasolines) V L (Use soil gas) (Use soil gas) <br /> PH(middle distillates) V L (Use soil gas) (Use soil gas) <br /> PH(residual fuels) NV US <br /> 1,2,4-Trichlorobenzene V L 2.5E+03 7.1E+03 <br /> 1,1,1-Trichloroethane V L 1.3E+05 3.6E+05 <br /> 1,1,2-Trichloroethane V L 3.5E+02 1.2E+03 <br /> Trichloroethene V L 5.3E+02 1.8E+03 <br /> 2,4,5-Trichlorophenol V S 8.3E+05 1.2E+06 <br /> 2,4,6-Trichlorophenol NV S <br /> Vanadium NV S <br /> Vinyl chloride V G 3.8E+00 1.3E+01 <br /> Xylenes V L 1.6E+05 1.6E+05 <br /> inc NV S <br /> Notes: <br /> 1,'Residential"screening levels generally considered adequate for other sensitive uses(e.g.,day-care centers, <br /> hospitals,etc.). <br /> 2.High permeability soil model:One meter dry sandy soil(92%sand,5%silt,3%clay)over one meter moist clayey <br /> loam(33%sand,34%silt,33%clay). j <br /> Screening levels calculated using spreadhseet provided with User's Guide for the Johnson and Ettinger Indoor Air <br /> model(1991)for Subsurface Vapor <br /> Intrusion Into Buildings(USEPA 2003). Assumed vadose-zone thickness/depth to groundwater three meters. See <br /> ppendix 1 text for model details. <br /> Physical state of chemical at ambient conditions(V-volatile,NV-nonvolatile,S-id,L-liquid,G-gas). <br /> Chemical considered to be"volatile"if Henry's Law constant(atm m3/mole)>0.00001 and molecular weight<200. <br /> Dibromochloromethane,dibromochloropropane and pyrene considered volatile for purposes of modeling(USEPA <br /> 2004). <br /> 11 arget cancer risk=1 E-06,Target Hazard Quotient=0.2 <br /> INTERIM FINAL- November 2007 <br /> SF Bay RWQCB Page 3of3 Table E-1a (GW to IA) <br />