Document B57jRkKZO063LK8jVKnkb8aoL

Vinyl Chloride: Chronic Inhalation RfC Critical Study: Exposures: Effect: Type of data: Data presented: NOAEL: LOAEL: Adjustment: Uncertainty Factor: Current RfC: PBPK Dose Metric: Bi et al. (1984) rats, inhalation: 0, 10, 100, 300 ppm; 6 months, 6 d/wk, 6 hr/d Liver effects (increased liver/body weight ratio) Continuous, grouped Number of subjects, mean response and concentration for each group. None identified 10 ppm Daily time-weighted average 3000 (10: use of LOAEL, 10: sub-chronic to chronic, 3: animal to human, 10: variability) 0.8 ppb Amount metabolized per gram liver CMA 113558 Impact of PBPK Modeling on the RfC for Vinyl Chloride (Preliminary) Current RfC: 0.0019 mg/m3 LOAEL,hec, -- 5.5mg/m3 UF = 10(LOAEL)x 10(A-H)x 10(SC-C)x 10(HIV) = 3000 PBPK RfC: 0.16 mg/m3 LOAEL|HEC| = 47.8 mg/m3 UF = 3(LOAEL)x3(A-H)x3(SC-C)x 10(HIV) = 300 Impact: 84-fold increase CMA113559 Vinyl Chloride: Chronic Inhalation RfC Critical Study: Exposures: Effect: Type of data: Data presented: NOAEL: LOAEL: Adjustment: Uncertainty Factor: PBPK/BMD RfC: PBPK Dose Metric: Feron et at. (1981) rats, dietary: 0, 1.7, 5.0, 14.1 mg/kg/d, 2 yrs; gavage: 300 mg/kg/d, 2 yrs, 5 days/week Liver effects (increased liver/body weight ratio) Quantal, grouped Number of subjects, number abnormal, and dose for each group. 1.7 mg/kg/d 5.0 mg/kg/d Daily average (gavage dose) 30 (3: animal to human, 10: variability) 0.7 ppm Amount metabolized per gram liver CMA 113560 Impact of PBPK and BMD Modeling on the RfC for Vinyl Chloride (Preliminary) Current RfC: 0.0019 mg/m3 LOAELju^i " 5.5mg/m3 UF = 10(LOAEL)x 10(A-H)x 10(SC-C)x 10(HIV) = 3000 PBPK/BMD RfC: 1.8 mg/m3 BMDL(0 = 55 mg/m3 UF = 3(A-H)xS*S=)xl0(HIV) = 30^ Impact: 947-fold increase cn CD CMA113: