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EC number: 918-668-5
CAS number: 128601-23-0
Dose Oral 90d – NOAEL = 600 mg/Kg bw for rats (similar to OECD TG 408)
Dose Inhalation 12 month – NOAEC = 900 mg/m3 for rats
(similar to OECD TG 413)
In the subchronic study on the oral toxicity
of 1,3,5-TMB, groups of 10 male and 10 female Sprague Dawley rats were
administered via gavage 0, 50, 200, or 600 mg/kg 1,3,5-TMB in corn oil 5
days/week for 90 days. An additional group of rats (10/sex) were
administered 600 mg/kg 1,3,5-TMB for 90 days and retained without
treatment for 28 days. Based on a lack of adverse effects at the highest
dose level (reversible effects such as increased serum phosphorus levels
and liver and kidney weights), the no-observed-adverse-effect level
(NOAEL) for this study is therefore considered to be 600 mg/kg-day.
Twenty-five male rats and four dogs per
level were exposed for 6 hr/day, 5 days/wk for 13 wk. Another 20 rats,
from the same week of production, were maintained for use as challenge
exposure controls (naive rats). The challenge exposures were run to
determine whether the 6-hr daily inhalation of a non-lethal level of
hydrocarbon, would result in the rat becoming more or less resistant.
One rat at the 0.10-mg/liter level died after 14 days. Death was
attributed to a pneumonic infection as evidenced by extensive lung
abscesses. None of the observations were dosage-related and are
discounted for that reason. The test material’s NOAEC > 0.38 mg/liter
(66 ppm), which was the highest achievable vapor concentration.
This study examined the effects of 12 months
of inhalation exposure of rats to a commercial mixture of Hydrocarbons,
C9 Aromatics. Male and female rats were exposed to concentrations of
450, 900, or 1800 mg/m³ 6 hrs/day, 5 days/week, for up to 12 months.
Some of the rats were sacrificed at 26 weeks, others at 12 months, and
others after a 4 month recovery period after the end of the 12 month
exposure. Animals were examined for clinical signs and behaviour twice
daily, and weighed weekly for the first 4 weeks, and monthly thereafter.
After sacrifice, the animals were examined for clinical chemistry,
hematology, urine analysis, gross pathology, histopathology, and organ
weights. No deaths attributable to exposure to the test substance
occurred. There was depressed weight during the first few months of the
experiment in medium (900 mg/m³) and high dose males (1800 mg/m³).
However, the animals quickly recovered and this effect is not considered
biologically significant. High dose females (1800 mg/m³) had depressed
weight gain for the first 3 months of exposure, but recovered in
subsequent months and in the satellite recovery group. No other adverse
effects attributable to exposure to the test substance were seen. Based
on the reversibility of the reduced weight gain and the lack of any
noted pathology, the NOAEC for male rats was 1800 mg/m³ and the NOAEC
for female rats was 900 mg/m3.
C9 aromatics are expected to have a low order of repeated dose toxicity
by the oral route of exposure. All tests were performed in a manner
similar or equivalent to currently established OECD guidelines. In a
repeated dose study where the test substance, 1,3,5-trimethylbenzene,
was administered via oral gavage, no toxicity was observed and
characterized at the highest dose tested of 600 mg/Kg. Based on this
observation, the repeat oral dose NOAEL was determined to be 600 mg/Kg.
a 12 month chronic study where Hydrocarbons, C9 aromatics were
administered via inhalation, the NOAEC for male rats was determined to
be 1800 mg/m3, the highest concentration tested. The NOAEC
for female rats was determined to be 900 mg/m3, due to the
reduced body weight noted.
a 90-day sub-chronic inhalation toxicity study, twenty-five male rats
and four dogs per level were exposed for 6 hr/day, 5 days/wk for 13
weeks to Hydrocarbons, C10, aromatics. Another 20 rats, from the same
week of production, were maintained for use as challenge exposure
controls (naive rats). The challenge exposures were run to determine
whether the 6-hr daily inhalation of a non-lethal level of hydrocarbon,
would result in the rat becoming more or less resistant. One rat at the
0.10-mg/liter level died after 14 days. Death was attributed to a
pneumonic infection as evidenced by extensive lung abscesses. None of
the observations were dosage-related and are discounted for that reason.
The test material’s NOAEC was determined to be >0.38 mg/L (66 ppm),
which was the highest achievable vapor concentration.
supporting 90-day sub-chronic toxicity study examined the effects of 13
weeks of inhalation exposure of Hydrocarbons, C9, aromatics to rats.
Male and female rats were exposed to 353, 706, and 1437 ppm of test
substance 6 hrs/day, 5 days/week, for 13 weeks. Animals were observed
daily for clinical signs, and body weights measured weekly. Blood
samples were taken at the end of exposure and examined for hematological
and clinical chemistry parameters. Animals were then sacrificed and
histopathology, gross pathology, and organ weight parameters were
examined. Body weight gains were significantly reduced in high exposure
(1437 ppm) males and females, and medium exposure (706 ppm) females. Low
grade anemia was present in females in all three exposure groups. The
NOAEC for male rats is 706 ppm, and the LOAEC is 1437 ppm based on
reduction in body weight gain. The LOAEC for female rats is 353 ppm
based on low grade anemia.
on available data, Hydrocarbons, C9, aromatics do not warrant
classification as a repeated dose toxicant under Regulation (EC)
1272/2008 on classification, labelling and packaging of substances and
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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