Appendix D - Dossier (PDF) - Tera

date: 20–JUL–2005
5. Toxicity Substance ID: 71–43–2
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Type: Micronucleus assay
Species: hamster Sex: male/female
Strain: other
Route of admin.: gavage
Exposure period: 24 hours
Doses: 0, 2.5, 10 ml/kg bw/day (converts to 0, 2.2, 8.8 g/kg bw/day)
Method: other
GLP: no data
Test substance: other TS
Remark: Groups of ten male and ten female Chinese hamsters were
administered benzene in peanut oil. Control animals
received peanut oil. The animals were given two
administrations, of the same benzene dose, at 24–hour
intervals. The hamsters were injected intraperitoneally
with colchicine 3 hours after the second benzene dose and
were killed 3 hours later. Bone marrow cells from the femur
were collected and prepared for micronucleus determination.
Result: No dose–related increase in the numbers of polychromatic
erythrocytes with micronuclei were found. In the females
given 2.2 g/kg bw/day, there was a slight increase in the
mean number of micronuclei but this was not seen at the
higher dose or in the male animals.
Source: BP Chemicals Ltd LONDON
Test substance: "Chemically pure" benzene tested.
13–DEC–1996 (1042)
Type: Micronucleus assay
Species: mouse Sex: male/female
Strain: CD–1
Route of admin.: gavage
Exposure period: single dose
Doses: 880 mg/kg bw
Method: other
GLP: no data
Test substance: no data
Remark: Benzene was administered in distilled water to male, female
and, on day 13 of gestation, pregnant mice. At different
periods after treatment, four animals were killed. Foetal
liver and adult bone marrow cells were obtained and assessed
for micronuclei. Further groups of animals were exposed to
the benzene metabolites, catechol, p–benzoquinone, phenol,
1,2,4–benzenetriol, hydroquinone, o,o’–biphenol and
p,p’–biphenol.
Result: Micronucleus induction was statistically significantly
elevated in the males, females and pregnant females at each
monitoring period. The males were more susceptible than the
females and the virgin females more so than the pregnant
females. Micronuclei were also induced in the foetal liver
cells together with a high cell toxicity. All of the tested
benzene metabolites induced micronuclei and, with the
exception of catechol and 1,2,4–benzene–triol, produced
myelotoxicity. The investigators concluded that the
induction of micronuclei by benzene cannot be attributed
Appendix D: Benzene SIDS Dossier
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