home edit2 whole TSD November 2002 PDF format - OEHHA

Table 1. Liver tumors in Colworth male and female rats exposed to drinking water containing N-
nitrosodiethylamine (NDEA) (Peto et al., 1982)
NDEA
(ppm)
concentration
Observed deaths from liver tumors
males
females
0 1/240 1/240
0.033 1/60 0/60
0.066 0/60 0/60
0.132 5/60 1/60
0.264 2/60 1/60
0.528 4/60 3/60
1.056 8/60 23/60
1.584 14/60 37/60
2.112 7/60 38/60
2.640 17/60 47/60
3.168 17/60 42/60
4.224 26/60 42/60
5.280 26/60 43/60
6.336 30/60 47/60
8.448 25/60 55/60
16.896 44/60 49/60
A later analysis by Peto et al. (1984) showed that, in rats, the initial age of contact with NDEA was
important in determining the probability of liver cancer. Young rats were much more susceptible than
adults to NDEA-induced liver neoplasia than adults exposed for an equal amount of time.
Lijinsky et al. (1981) administered NDEA in the drinking water to 11 groups of female Fisher-344 rats
(20 per group) for varying durations, up to 104 weeks. The animals were observed for their lifespan.
The treatment groups are shown in Table 2.
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