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espiratory tumors were noted in the control groups. CDHS (1988) noted that only 18%, 26% and
approximately 50% of the animals in the 30 ppm, 10 ppm and 100 ppm dose groups, respectively,
survived to mean time-to-tumor observed in the 100 ppm group (86 weeks).
Konishi et al. (1980) exposed male Wistar rats (18/group) to epichlorohydrin in drinking water at
concentrations of 0, 375, 750 or 1500 ppm for up to 81 weeks; treatment was intermittently suspended
between 60 and 81 weeks for all three epichlorohydrin treatment groups due to toxicity. Total dose for
the 375, 750 and 1500 ppm treatment groups was 5.0, 8.9 and 15.1 g/animal, respectively. A doserelated
increase in forestomach tumor (papillomas and squamous cell carcinomas) incidence was
observed. Tumor incidence data is listed in Table 1.
Table 1:
Incidence of forestomach tumors in male Wistar rats exposed to epichlorohydrin in
drinking water (Konishi et al., 1980)
Concentration
(ppm)
Calculated dose 1
(mg/kg-day)
Tumor incidence
papillomas squamous cell
carcinomas
0 0 0/10 0/10
375 15.1 0/9 0/9
750 31.9 1/10 1/10
1500 76.1 7/12 2/10
1. As listed in CDHS (1988).
Male and female ICR/HA Swiss mice (50/sex/group) were exposed to pure (99.9%) trichlorethylene
(TCE), industrial grade (99.4%) TCE, or TCE containing 0.8% ECH, 0.8% 1,2-epoxybutane, or 0.8%
ECH and 0.8% 1,2-epoxybutane by gavage for 104 weeks (Henschler et al., 1984). Corn oil vehicle
control groups were included. Initial dosing provided TCE exposures of 2400 mg/kg/day -1 and 1800
mg/kg/day -1 for male and female mice, respectively. Because of toxicity, dosing was halted for all
groups during weeks 35-40, 65 and 69-78. All doses were reduced by a factor of 2 at week 40.
Mortality was significantly increased compared to controls in all male treatment groups, and in female
treatment groups receiving pure TCE and TCE/ECH. Significant increases in the incidence of squamous
cell carcinomas of the forestomach were observed in both male and female animals exposed to
TCE/ECH. The tumor incidence in animals exposed to pure TCE was comparable to control values.
Tumor incidence data is listed in Table 2.
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