Appendix D - Dossier (PDF) - Tera

date: 20–JUL–2005
5. Toxicity Substance ID: 71–43–2
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Species: mouse Sex: male
Strain: NMRI
Route of administration: inhalation
Exposure period: 2 wk
Frequency of treatment: 8 hr/d, 5 d/wk or additional experiments on 0–8 hr/d, 5
d/wk
Doses: 0, 10, 21, 50, 95, 107 ppm
NOAEL: 10 ppm
Method: other
Method: Additional experiments included exposure to 95 and 201 ppm
on 0–8 h/d, 5 d/w for 2 weeks.
Parameters examined in bone marrow/tibia: cellularity,
number of colony–forming unit granulopoietic stem cells
(CFU–C) and micronucleated polychromatic erythrocytes
(MN–PCE).
Result: Intermittent exposures on 8 hr/d, 5 d/w during 2 weeks to
10, 21, 50, 95, or 107 ppm revealed that exposure to 21 ppm
was the lowest dose tested yielding suppressed CFU–C content
and elevated frequency of MN–PCE. Bone marrow cellularity
was depressed at doses of 50 ppm and above.
Additional experiments including exposure to 95 and 201 ppm
on 0–8 h/d, 5 d/w for 2 weeksm revealed depressive effects
on bone marrow cellularity and CFU–C content at
concentration of 95 ppm at the 6 hr/d regimen, the number of
MN–PCE were increased at 4 h/d exposure time. 201 ppm for 2
hr/d suppressed cellularity and increased numbers of MN–PCE,
but did not alter significantly CFU–C content indicating
that at high exposures of short duration bone marrow cell
numbers were the most sensitive parameter. At the 4 hr/d
dose regimen 201 ppm caused changes of all three parameters.
Source: German Rapporteur
Flag: Risk Assessment
25–OCT–2000 (1143)
Species: mouse Sex: male/female
Strain: other: C57BL1/6 BNL
Route of administration: inhalation
Exposure period: 2 wk
Frequency of treatment: 6 h/d, 5 d/wk
Doses: 10, 25, 100, 400 ppm (32, 80, 320, 1280 mg/m³)
Control Group: yes
NOAEL: 10 ppm
Method: other
Method: Male and female C57B1/6 BNL mice (5–10 animals/group) were
exposed to benzene vapour at concentration of 0, 10, 25,
100, or 400 ppm (32, 80, 320, or 1280 mg/m³) for 2 weeks (6
hr/d, 5 d/w).
Result: At 100 ppm reduced bone marrow cellularity (no data on
higher doses) was reduced. A decreased number of pluripotent
stem cells in bone marrow and a higher fraction of stem
cells in DNA synthesis were reported at 100 and 400 ppm. In
peripheral blood hematocrit was reduced at 100 ppm and above
Appendix D: Benzene SIDS Dossier
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