Appendix D - Dossier (PDF) - Tera

date: 20–JUL–2005
5. Toxicity Substance ID: 71–43–2
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cells were exposed to benzene for 1 hr in the absence of
serum and the presence and absence of S9 mix.
Cyclophosphamide and ethylmethanesulphonate were used as
positive controls, in the presence and absence of S9 mix
respectively. The concentrations of benzene tested included
at least one dose that induced measurable cytotoxicity and
one higher dose. The S9 mix used was derived from livers of
male albino rats treated with phenobarbital and
beta–naphthoflavone.
Reliability: 1 (valid)
Comparable to guideline study
results: The maximum non–toxic benzene dose in the
cytotoxicity assay was 0.31 mg/ml when tested for 4 hr in
the presence of serum and the presence and absence of S9 or
in the absence of serum and the presence of S9. When tested
without S9, in the absence of serum, the maximum non–toxic
dose was 0.63 mg/ml. In the colony forming assay, the
highest non–toxic dose when tested with and without serum
and with and without S9 mix was 0.003 mg/ml and the
concentration which killed 50% of the cells in the presence
of serum and the absence and presence of S9 mix was 1 mg/ml
and >1 mg/ml in the absence of serum. In the mutagenicity
assay, the mutation frequency was evaluated 5 and 8 days
after exposure. No mutagenic activity was found.
Source: Deutsche Shell Chemie GmbH Eschborn
Test substance: Laboratory reagent grade; 99% pure.
06–JAN–1997 (368)
Type: HGPRT assay
System of testing: Chinese hamster V79 cells
Concentration: 1, 10, 50, 100, 500, 1000 ug/ml
Metabolic activation: with and without
Result: positive
Method: other: in compliance with OECD Guide–line 476
Year: 1984
GLP: no data
Test substance: other TS
Remark: A preliminary cytotoxicity study was carried out using this
same cell line treated with 1, 10, 50, 100 and 500 ug/ml for
3 hours. The treated cells were then rinsed with Hanks’
solution and incubated in normal medium for a further 7 days
before the colony–forming activity was evaluated. The
mutagenic activity was determined by the ’replating’ method.
Cells were treated for 3 hours with benzene, rinsed with
Hanks’ solution and then incubated in normal medium for 6
days. They were then treated with trypsin, replated in
medium containing 6–thioguanine and incubated for 14 days.
The number of 6–thioguanine–resistant colonies was scored.
The assay was conducted in the absence and presence of a
metabolic activation system (S9 mix) which had been obtained
from male Sprague–Dawley rats treated with an
intraperitoneal injection of phenobarbital and
5,6–benzoflavone. Benzene was dissolved in
dimethylsulphoxide before use and diluted with Hanks’
solution to obtain the appropriate concentration for
Appendix D: Benzene SIDS Dossier
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