Appendix D - Dossier (PDF) - Tera

date: 20–JUL–2005
5. Toxicity Substance ID: 71–43–2
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Reduced tumor resistance mediated via T–lymphocytes was
observed in 9 out of 10 male C57Bl/6J mice exposed to 100
ppm benzene (320 mg/m³) for a total of 100 days (6 hr/d, 5
d/w, 20 weeks) and challenged with 10.00 polyoma
virus–induced tumor cells/mouse. These mice developed tumors
that were lethal. Lethal tumor incidences in air controls
and mice exposed to 10 or 30 ppm benzene concentrations were
3/10 or less.
Source: German Rapporteur
Flag: Risk Assessment
06–JUL–2005 (960)
Species: mouse Sex: male
Strain: other: C57Bl/6
Route of administration: inhalation
Exposure period: 5 d prior to infection, additional subgroup with
postinfectional exposure on 7 d
Frequency of treatment: 6 h/d,
Post exposure period: 7 d
Doses: 10, 30, 100, 300 ppm followed by infection with
Listeria monocytogenes
NOAEL: 10 ppm
Method: other
Method: Host resistence test, 5–7 animals/group
Result: Continuous exposure to concentrations as low as 30 ppm (96
mg/m³) of benzene resulted in a delay in immune response of
T–cells and macrophages after induction of bacterial
infection in C57BL/6 mice (Rosenthal and Snyder 1985).
Preexposure of male C57Bl/6J mice (5–7 animals/group) to
benzene at 10, 30, 100, or 300 ppm for 5 days followed by
infection with Listeria monocytogenes with continuous
exposure on 7 days or without continuouing the exposure
increased the bacterial counts in mice of the 300 ppm group
of the preexposure group and in mice at 30, 100, and 300 ppm
of the continuous exposure groups on day 4, but not days 1
or 7. Nucleated cells, lymphocytes, T– and B–lymphocytes and
monocytic/macrophagic cells per spleen increased from day 1
to day 7 of infection in air control groups. Significant
depressions of the mentioned cell types except the
monocytic/macrophagic cells were observed in each exposure
regimens at 30 ppm or higher concentrations from day 1
through day 7 of bacterial infection.
Source: German Rapporteur
Flag: Risk Assessment
06–JUL–2005 (959)
Appendix D: Benzene SIDS Dossier
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