hexachlorobutadiene - Davidborowski.com
hexachlorobutadiene - Davidborowski.com
hexachlorobutadiene - Davidborowski.com
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HEXACHLOROBUTADIENE 31<br />
2. HEALTH EFFECTS<br />
from dams exposed to <strong>hexachlorobutadiene</strong> at dose levels of 20 mg/kg/day throughout gestation and<br />
lactation; body weights were not reduced in pups from dams exposed to 2 mg/kg/day. No other signs<br />
of fetotoxicity were evident at doses up to 20 mg/kg/day. Teratogenic effects were not observed nor<br />
was <strong>hexachlorobutadiene</strong> embryotoxic at the doses tested (Schwetz et al. 1977).<br />
The highest NOAEL values and all LOAEL values from each reliable study for developmental effects<br />
in each species and duration category are recorded in Table 2-2 and plotted in Figure 2-2.<br />
2.2.2.7 Genotoxic Effects<br />
No studies were located regarding genotoxic effects in humans after oral exposure to<br />
<strong>hexachlorobutadiene</strong>.<br />
In animals, there is some evidence that <strong>hexachlorobutadiene</strong> interacts with genetic material. Male rats<br />
administered a single gavage dose of <strong>hexachlorobutadiene</strong> (20 mg/kg/day) showed a 40% increase in<br />
renal deoxyribonucleic acid (DNA) repair and 0.78 alkylations per million nucleotides (Stott et al.<br />
1981). On the other hand, when <strong>hexachlorobutadiene</strong> was administered in the diet, it did not cause<br />
chromosomal aberrations in rat bone marrow cells (Schwetz et al. 1977).<br />
Other genotoxicity studies are discussed in Section 2.4.<br />
2.2.2.8 Cancer<br />
No studies were located regarding carcinogenic effects in humans after oral exposure to<br />
<strong>hexachlorobutadiene</strong>.<br />
Studies in rats reported renal tubular adenomas and adenocarcinomas in male and female animals at<br />
doses of 20 mg/kg/day (Kociba et al. 1977a). Metastasis to the lungs was observed. Combined<br />
incidences of renal tubular neoplasms in males (9/39, 23 %) and in females (6/40, 15 %) increased<br />
(p < 0.05) over controls (males-l/90, females-0/90, 0%). The tumor incidence was not increased in<br />
the 0.2 and 2 mg/kg/day dose groups but there were some indications of hyperplasia in animals<br />
exposed to 2 mg/kg/day. The EPA (1990f) evaluated these data and calculated a human potency<br />
factor of 7.8x10 -2 (mg/kg/day) -1 (q1*), representing a 95% upper confidence limit of extra lifetime