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EC number: 232-140-5
CAS number: 7789-00-6
High quality (NTP) studies using oral dosing are available for sodium dichromate and potassium dichromate in the rat and mouse. Repeated dose inhalation exposure studies are available for chromium trioxide. Longer term toxicity and carcinogenicity studies are also availabel for compounds in this group
Repeated dose oral toxicity
No studies of repeated dose oral toxicity are available for chromium
(VI) trioxide, however studies are not required as the primary route of
occupational exposure is likely to be inhalation. Reliable repeated dose
studies are available, however, for potassium dichromate and sodium
dichromate and the results of these studies can be extrapolated to the
other members of the group.
Two NTP combined repeat dose / reproductive toxicity screening studies
have been performed with potassium dichromate in the rat and mouse; the
studies used dietary administration for up to 9 weeks. Although there
was some evidence for a treatment-related effect on erythrocyte
parameters in both studies, findings were of small magnitude and were
not considered to be of toxicological significance. Findings of
toxicological significance were limited to reduced bodyweight gain in
male mice at the high dose level of 400 ppm (32 mg/kg bw/d Cr (VI)).
Two NTP 90-day carcinogenicity sighting studies were performed with
sodium dichromate in the rat and mouse using administration in drinking
water. The results of these studies show effects on bodyweight and food
consumption and (most markedly), a microcytic hypochromic anaemia
consistenet with an effect of Cr (VI) on iron homeostasis and/or
haemoglobin synthesis. Histopathology revealed local irritant effects on
the gastric mucosa. Findings were apparent at the lowest dose levels in
these studies, equivalent to 1.7 and 3.1 mg/kg bw/d Cr (VI) in the rat
and mouse respectively.
Repeated dose dermal toxicity
No studies of repeated dose dermal toxicity are available for this group
of compounds, however the relevance of such studies to human
occupational risk assessment will be severely limited by the corrosive
nature of the compound. In practice, human dermal exposure will also be
self-limiting. Given the corrosivity and the low dermal penetration of
these compounds, findings in repeat-dose dermal toxicity studies will be
limited to local (site of contact) effects; systemic effects are not
predicted with the exception of non-specific effects secondary to local
corrosivity. Additionally, performing repeated dose dermal toxicity
studies cannot be justified on animal welfare grounds.
Repeated dose inhalation toxicity
The results of two published repeated exposure inhalation studies in the
mouse (Adachi et al, 1986; Adachi, 1987) performed over periods of up to
12 months show that the primary effects of exposure are local corrosion
and irritation of the respiratory tract. Findings were observed in mice
following exposure to a concentration of 3.63 mg/m3 for 30 minutes,
twice a week for up to one year; or in mice exposed to concentrations of
1.81 mg/m3 for 60 minutes, twice a week for one year. The results of
this study can be extrapolated to the other compounds in this group.
Chromium trioxide, sodium dichromate, potassium dichromate and sodium
chromate are listed on Annex I of Directive 67/548/EEC and are
classified as (R48/23) ' Toxic: danger of serious damage to health by
prolonged exposure through inhalation'. No change to this classification
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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