Teratogenicity studies on halogenated benzenes (pentachloro-, pentachloronitro- and hexabromo-) in rats

The fungicide, pentachloronitrobenzene (PCNB), and fire retardants, pentachloro- (QCB) and hexabromobenzene (HBB) were administered orally to rats at 0, 50, 100 or 200 mg/kg on day 6-15 of gestation. The highest doses were associated with loss of maternal body weight gain but the loss was not statistically significant. At term, all dams were killed and foetuses removed to determine effects on prenatal survival and morphological development. All doses of QCB increased the foetal incidence of extra ribs in a dose-related manner while the 200 mg/kg dose also reduced the mean foetal weight and increased the incidence of sternal defects. PCNB and HBB had no effect at all doses.