1,2,3,4,5-Pentabromo-6-chlorocyclohexane

Chronic toxicity and oncogenicity were evaluated in Fischer 344 rats (86/sex/control group, 50/sex/treated group) orally exposed to 1,2,3,4,5-pentabromo - 6-chlorocyclohexane (PBCC) in the diet for 2 years at 0, 1, 20 and 70 mg/kg/day for females and at 0, 1, 15 and 50 mg/kg/day for males based on the differential toxicity of PBCC to males and females in previous studies. There were significant differences between treated animals and controls in the following: body weights (decreased for both sexes at high-dose levels), and tissue bromine level (increased to plateau at mid- and high-dose levels in liver, fat and serum in approximately equal concentrations). There were significant increases observed in the necropsy histopathology of the colon of high-dose animals of both sexes: hemorrhage, fluid ingesta and mass or polyp formations; polyploid formations, dilatation, hypercellularity and aggregates of cellular debris in intestinal crypts, and primary polyploid adenoma or carcinoma. There were no significant differences between treated animals and controls in the following: palpable masses, mortality, clinical chemistry, hematology, urinalysis, organ weights, or necropsy and histopathology (except for that of the colon).

The distribution of alpha-1,2,3,4,5-pentabromo - 6-chlorocyclohexane (PBCC) as measured by the total bromine content in adipose, liver and kidney tissues was evaluated in male and female CDF Fischer 344 rats (10/sex/group) fed PBCC at concentrations of 0 or 600 mg/kg/day in Purina Laboratory Chow for 91 days. Statistically significant increases in bromine levels were observed in all analyzed tissues of all treated animals (P < 0.05, Dunnett's test) relative to control animals. The bromine levels (ug/g) in the adipose, liver and kidney tissues of male animals (treated/control) were: 93/2.3, 413/3.9 and 810/7.7, respectively; and of female animals: 117/2.4, 429/5.9 and 750/9.4, respectively. The total bromine in these tissues accounted for approximately 2% of the PBCC ingested during the 13 week exposure period. The biological half-life could not be determined from the data obtained from the tests.

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1,2,3,4,5Pentabromo-6-Chlorocyclohexane

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Suggestive evidence of carcinogenic potential

2016

2.70e+01

1.10e+02

2.80e+00

2.00e+02

1.60e-02

2.00e-02

2.70e+03

1.10e+04

2.80e+02

2.00e+02

2.00e-02

2.00e-02