hexachlorobutadiene - Davidborowski.com

HEXACHLOROBUTADIENE 66
2. HEALTH EFFECTS
hazardous waste sites; therefore, additional short-term animal studies by oral routes may be useful to
more thoroughly assess the potential human health risk.
Intermediate-Duration Exposure. No data are available on the effects of hexachlorobutadiene in
humans after intermediate-duration inhalation, oral, or dermal exposures. In animals, data on
inhalation exposure are limited to one developmental toxicity study in rats in which maternal body
weights were reduced at a concentration (15 ppm) that was also fetotoxic (Saillenfait et al. 1989).
Oral studies revealed kidney damage in female mice at dose levels of 0.2 mg/kg/day (NTP 1991;
Yang et al. 1989). This LOAEL was used to derive an intermediate-duration oral MRL of
0.0002 mg/kg/day .
Liver damage was evident in male rats at dose levels of 6.3 mg/kg/day but not at dose levels of
2.5 mg/kg/day for 13 weeks (Harleman and Seinen 1979). Treatment-related histopathological
hepatic lesions were not seen in females. Some serum biochemical parameters (aspartate
aminotransferase and total bilirubin), were increased at doses of 20 mg/kg/day for 4 weeks (Jonker
et al. 1993b). No data are available on the effects of hexachlorobutadiene in animals after
intermediate-duration dermal exposure. Inhalation exposure to vaporous hexachlorobutadiene can
occur when this material is exposed to the environment. Studies of toxicity from material absorbed
through the lungs are justified.
Chronic-Duration Exposure and Cancer. Data in humans are limited to one study that reported
increases in serum bile acids in workers chronically exposed to vapors of hexachlorobutadiene
(0.005-0.02 ppm). Because workers were also potentially exposed to other chemicals (carbon
tetrachloride and perchloroethylene), these effects cannot be attributed to hexachlorobutadiene
exposure alone. No studies are available on the effects of hexachlorobutadiene in humans after oral
or dermal exposure.
In animals, a chronic-duration oral rat study showed that the kidney was the target organ following
chronic exposure to hexachlorobutadiene. Kidney damage as well as evidence of impaired kidney
function were evident in female rats at dose levels of 2 mg/kg/day, but not at 0.2 mg/kg/day (Kociba
et al. 1977a). Since the intermediate-duration oral MRL is protective against affects on the kidney
following lifetime exposure, a chronic MRL was not derived. Data are not available to derive a