home edit2 whole TSD November 2002 PDF format - OEHHA

A linearized multistage procedure was used to estimate the cancer potency of NDBA from the Bertram
and Craig. (1970) data in male C57Bl/6 mice (Crump et al., 1982). The 95% upper confidence bound
on the dose-response slope was used to derive the human cancer potency value.
The animal cancer potency, q animal , was calculated from the linear slope using the lifetime scaling factor
q animal = q 1 * × (T/T e ) 3 , where T/T e is the ratio of the experimental duration to the lifetime of the animal.
In this case, the scaling factor was equal to 1. An estimated value for the human cancer potency was
determined using the relationship q human = q animal × (bw h /bw a ) 1/3 , where bw is the default body weight
of human or animal (mouse).
Using these relationships, a human cancer potency (q human ) of 10.8 [mg/kg-day] -1 was calculated for
NDBA (CDHS, 1988). An airborne unit risk factor of 3.1E-3 (µg/m 3 ) -1 was calculated by
OEHHA/ATES from the q human value using the default parameters of 70 kg human body weight and
20 m 3 /day breathing rate.
V. REFERENCES
Althoff J, Mohr U, Page N and Reznik G. 1974. Carcinogenic effect of dibutylnitrosamine in European
hamsters (Cricetus cricetus). J Natl Cancer Inst 53:795-800.
Althoff J, Pour P and Cardessa A. 1973. Comparative studies of neoplastic response to a single dose
of nitroso compound. II. The effect of N-dibutylnitrosamine in the Syrian golden hamster. Z Krebsforsh
79:85-89.
Bertram JS and Craig AW. 1970. Induction of bladder tumors in mice with dibutylnitrosamine. Br J
Cancer 24:352-359.
California Department of Health Services (CDHS). 1985. Guidelines for Chemical Carcinogen Risk
Assessment and their Scientific Rationale. State of California Health and Welfare Agency, Department
of Health Services, 2151 Berkeley Way, Berkeley, CA.
California Department of Health Services (CDHS). 1988. Risk-specific Intake Levels for the
Proposition 65 Carcinogen N-Nitroso-n-dibutylamine. Reproductive and Cancer Hazard Assessment
Section, Office of Environmental Health Hazard Assessment, 2151 Berkeley Way, Berkeley, CA.
Cohen AE, Weisburger EK, Weisburger JH, Ward JM and Putnam CL. 1975. Cytoscopy of
chemically induced bladder neoplasms in rabbits administered the carcinogen dibutylnitrosamine. Invest
Urol 12:262-266.
Crump KS. 1982. An improved procedure for low-dose carcinogenic risk assessment from animal
data. J Environ Path Toxicol 5(2):675-684.
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