Laserfiche WebLink
FMS #24 Site Investigation Report <br />California Army National Guard <br />a Maximum detected concentration from any of the four samples collected from 8 feet below ground surface. <br />b Unit conversion for soil -gas concentrations: <br />Concentration (pg/m3) _ [Concentration (ppbv) - 1,000] x MWx41.5957 <br />where: <br />MW = molecular weight of the compound (g/mole); 41.5957 = constant ([mole-pg-L]/[m3-g-gL]), based on the Universal Gas Constant (R), unit conversion factors, standard temperature (20°C), and standard pressure (1 atm). <br />Default attenuation factor (Table 2; DTSC, 2005) for existing slab -on -grade commercial land use <br />d Toxicity values from the California Environmental Protection Agency, Office of Environmental Health Hazard Assessment (http://www.oehha.ca.gov/risk/ChemicalDB/index.asp ). <br />day/yr <br />= days per year <br />Table 3-7. Risk and Hazard Estimates — Inhalation of Volatile Organic Compounds <br />= Department of Toxic Substances Control <br />FMS <br />= Field Maintenance Shop <br />g/mole <br />= grams per mole <br />kg <br />Current Conditions — Existing <br />Commercial/Industrial Land Use <br />= parts per billion by volume <br />yrs <br />= years <br />gg/m3 <br />= micrograms per cubic meter <br />Stockton FMS #24 Site, Stockton, California <br />Description <br />Variable <br />Value <br />Equations <br />Attenuation Factor, Current Commercial <br />a <br />0.001 <br />dimensionless <br />Cancer Risk: <br />Averaging Time, carcinogens <br />AT, <br />70 <br />yrs <br />l d <br />IRAQ x EF x ED, x ET <br />= x 70 kg x <br />Risk URF x <br />C� <br />Q" x <br />� <br />Averaging Time, noncarcinogens, adult <br />ATnc,a <br />25 <br />yrs <br />20 m3 <br />BW,, X AT, x 365 days / year], <br />Body weight, adult <br />BWa <br />70 <br />kg <br />Chemical Concentration in indoor air <br />Cair <br />chemical -specific <br />pg/m3 <br />Noncarcinogenic Hazard: <br />Soil -Gas Concentration <br />Csoil-gas <br />chemical -specific <br />pg/m3 <br />Exposure Duration, adult <br />EDa <br />25 <br />yrs <br />1 <br />IRAQ X EF X ED, X ET 1I <br />Exposure Frequency <br />EF <br />250 <br />days/yr <br />Hazard = <br />X C . <br />X } <br />Fraction of EF breathing air at the site <br />ET <br />1 <br />unitless <br />RfC X 20 m3 x 1 <br />I l Q`r <br />BWQ x ATQ x 365 days/ year J <br />Inhalation Rate, adult <br />IRAs <br />14 <br />m3/8 -hr day <br />1 d 70 kg <br />Inhalation Reference Concentration <br />RfC <br />chemical -specific <br />Vg/M3 <br />where: <br />Inhalation Unit -Risk Factor <br />URFi <br />chemical -specific <br />(pg/m3)-1 <br />air — a X soil—gas <br />Soil Gas <br />Molecular <br />Cancer <br />Hazard <br />Concentration' <br />Weight <br />Csoil-gas b <br />ac <br />Cair URFi d <br />Risk <br />% of <br />RfC d Quotient <br />% of <br />Compound <br />(ppbv) <br />(g/mole) <br />(µg/m) <br />(dimensionless) <br />(µg/m) (µg/m)-' <br />(dimensionless) <br />Total <br />(pg/m3) (dimensionless) <br />Total <br />Volatile Organic Compounds <br />Benzene <br />6.5 <br />78.11 <br />2.11E+01 <br />0.001 <br />2.11E-02 2.90E-05 <br />1.05E-07 <br />21% <br />6.00E+01 1.69E-04 <br />4% <br />Naphthalene <br />13 <br />128.16 <br />6.93E+01 <br />0.001 <br />6.93E-02 3.40E-05 <br />4.03E-07 <br />79% <br />9.00E+00 3.69E-03 <br />93% <br />Toluene <br />7.1 <br />92.13 <br />2.72E+01 <br />0.001 <br />1.28E-02 No Toxicity Value <br />— <br />— <br />3.00E+02 4.35E-05 <br />1% <br />m,p-Xylenes <br />19 <br />106.17 <br />8.39E+01 <br />0.001 <br />8.39E-02 No Toxicity Value <br />— <br />— <br />7.00E+02 5.75E-05 <br />1% <br />Cancer Risk <br />Hazard Index <br />Cumulative: <br />5E-07 <br />0.0040 <br />a Maximum detected concentration from any of the four samples collected from 8 feet below ground surface. <br />b Unit conversion for soil -gas concentrations: <br />Concentration (pg/m3) _ [Concentration (ppbv) - 1,000] x MWx41.5957 <br />where: <br />MW = molecular weight of the compound (g/mole); 41.5957 = constant ([mole-pg-L]/[m3-g-gL]), based on the Universal Gas Constant (R), unit conversion factors, standard temperature (20°C), and standard pressure (1 atm). <br />Default attenuation factor (Table 2; DTSC, 2005) for existing slab -on -grade commercial land use <br />d Toxicity values from the California Environmental Protection Agency, Office of Environmental Health Hazard Assessment (http://www.oehha.ca.gov/risk/ChemicalDB/index.asp ). <br />day/yr <br />= days per year <br />DTSC <br />= Department of Toxic Substances Control <br />FMS <br />= Field Maintenance Shop <br />g/mole <br />= grams per mole <br />kg <br />= kilogram <br />ppbv <br />= parts per billion by volume <br />yrs <br />= years <br />gg/m3 <br />= micrograms per cubic meter <br />B-18 December 2007 <br />