Laserfiche WebLink
FORMER MOBIL BULK TERMINAL 04-343, TRACY, CALIFORNIA <br /> CALCULATION OF INCREMENTAL CANCER RISKS AND HAZARD INDICES <br /> VAPOR PATHWAY ANALYSIS Page 3 of 3 <br /> EXPOSURE: POTENTIAL EXPOSURE TO CHEMICALS IN SUBSURFACE SOIL <br /> RECEPTOR: RETAIL FACILITIES NORTH WEST OF SITE <br /> SITE CONDITION: FENCED, UNPAVED AND UNDEVELOPED --- - <br /> EXPOSURE SCENARIO: REASONABLE MAXIMUM EXPOSURE <br /> ENDPOINT;INCREMENTAL CANCER RISK <br />' EQUATIONS. <br /> LADD = Co(s)*RR *ED*EY* I/L* l/BW*BI <br /> RISK = LADD*CSF <br /> HI = Co(s)/RfC <br /> SYMBOLS AND DESCRIPTIONS UMTS VALUES RATIONALE <br /> Co(s) = Concentration of Chemical in Outside Air mg/m3 see below (by previous equation) <br /> RR = Human Respiration Rate m3/day 10 (by previous equation) <br /> ED = Exposure Duration dayslyear 240 (Maximum) <br /> EY = Exposure Duration years 20 (professional judgement) <br /> L = Days in Average Lifetime days 27375 (based on 75 years; EPA, 1989a) <br /> BW = Average Human Body Weight kg 70 (adult average; EPA, 1989b) <br /> BI = Bioavailability of Benzene through Inhalation dimensionless 1 (maximum value) <br /> LADD = Lifetime Average Daily Dose mg/kg-day see below (by equation) <br /> RfC = Reference Concentration mg/m3 see below (EPA, 199 1) <br /> CSF = Cancer Slope Factor for Benzene 11(mg/kg-day) 2.90E-02 (EI'A, 1991) <br /> Risk = Upper-Bound Incremental Cancer Risk dimensionless see below (by equation) <br /> HI = Hazard Index dimensionless see below (by equation) <br /> Chemical Cos LADD RfC Risk HI <br /> Benzene 9.60E-04 2.40E-05 NA 6.97E-07 NA <br /> Toluene 3.867-04 NA 2E+00 NA 1.93E-04 <br /> Ethylbenzene 2.45E-03 NA 1E+00 NA 2.45E-03 <br />' Xylenes 9.09E-04 NA 3E-01 NA 3.03E-03 <br /> i <br />!0 <br /> I' I <br /> RSKCALC4 <br />