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EC number: 232-140-5
CAS number: 7789-00-6
A number of studies performed with potassium dichromate are available.
Once systemically absorbed, the toxicokinetics and toxicodynamics of the
water-soluble Cr (VI) salts are essentially identical, therefore the
results of these studies are relevant and can be extrapolated to all
members of this group.
In a single generation fertility study in the mouse using administration
of potassium dichromate in drinking water, effects on fertility
resulting from the exposure of males and females were inidicated by the
reduction in the numbers of implantations; findings were apparent
following exposure of females to the lowest dose level equivalent to 140
mg/kg bw/d Cr (VI). Changes in reproductive organ weights were also seen
in this study but are not considered to be of clear toxicological
significance (Elbetieha & Al-Hamood, 1997) as they are associated with
bodyweight changes and do not have any pathological correlates. In
contrast, no evidence of reproductive toxicity was seen in an NTP
continuous breeding study (two generation) in the mouse using potassium
dichromate at dose levels of up to 40 mg/kg bw/d Cr (VI).
A number of published developmental toxicity studies performed in mice
with potassium dichromate are available. Mice were exposed either
throughout gestation (Trivedi et al, 1989), during organogenesis
(Junaid et al, 1996a) or prior to mating (Junaid et al
1996b). No evidence of teratogenicity was seen in any study, however
adverse effects on fertility (reduced corpora lutea, reduced
pre-implantation loss) were seen. Foetotoxicity (post-implantation loss,
resorptions) and developmental toxicity (reduced skeletal ossification
and subcutaneous haemorrhage) were seen consistently; findings were
apparent at dose levels of 20 mg/kg bw/d Cr (VI) and above.
Information on effects of Cr (VI) on the testes is available from
repeated oral dose studies. In the rat, testicular degeneration was
observed at a dose level (40 mg/kg bw/d (14 mg Cr(VI)/kg bw/d) which
caused a large decrease in body weight gain following gavage
administration of sodium dichromate for 90 days. A NOAEL of 20 mg/kg
bw/d (7 mg Cr(VI)/kg bw/d) was determined for effects on the testis.
Other studies found no effects on the testis, following administration
of potassium dichromate by the dietary route for 9 weeks. The highest
dose levels in these studies were 24 mg/kg bw/d (8 mg Cr(VI)/kg bw/d) in
the rat and 92 mg/kg bw/d (32 mg Cr(VI)/kg bw/d) in the mouse (EU RAR,
Summary and discussion of the available reproductive toxicity studies
from the EU RAR (2005)
There are three animal studies available which focus on fertility.
Adverse effects were produced in mice receiving potassium dichromate for
12 weeks in drinking water at 333 mg/kg bw/d (120 mg Cr(VI)/kg bw/d) and
400 mg/kg be/d (140 mg Cr(VI)/kg bw/d) and above in males and females
respectively. A NOAEL of 166 mg/kg bw/d (60 mg Cr(VI)/kg bw/d) was
identified in males, but no NOAEL was found for females as 400 mg/kg
bw/d was the lowest dose level tested. An increase in resorptions
following treatment of males and a decrease in implantations in treated
females were among the findings in this study. In another study,
pregestational oral administration of potassium dichromate in drinking
water to female mice produced adverse effects on fertility (reduced
number of corpora lutea and increased pre-implantation loss) at 500 ppm
(119 mg/kg bw/d (40 mg Cr(VI)/kg bw/d)) and above. NOAEL values of 119
mg/kg bw/d (40 mg Cr(VI)/kg bw/d) and 63 mg/kg bw/d (20 mg Cr(VI)/kg
bw/d) can be identified from this study for maternal toxicity and
fertility effects respectively. In a third study, also in the mouse, at
86 mg/kg bw/d (30 mg Cr(VI)/kg bw/d), the highest dose level tested,
there were no effects of treatment on fertility parameters.
Fetotoxicity, including post-implantation losses, has been observed in
the mouse following administration of potassium dichromate in drinking
water during gestation (days 0-19). Significant developmental effects
occurred at the lowest dose level tested, 60 mg/kg bw/d (20 mg Cr(VI)/kg
bw/d) in the absence of maternal toxicity. Therefore no developmental
NOAEL was determined. Qualitatively similar results were obtained in
another study in which (350 mg/kg) potassium dichromate (125 mg
Cr(VI)/kg) was administered for a shorter period, on days 6-14 of
gestation. In a pregestational study in female mice, fetotoxic effects
were seen starting from the lowest dose level tested, 250 ppm (63 mg/kg
bw/d (22.1 mg Cr(VI)/kg bw/d)) potassium dichromate. Significant levels
of total chromium were found in treated animals at sacrifice. No NOAEL
could be identified for the developmental effects, which included
post-implantation losses. These fetal effects may possibly be explained
by the presence of chromium in the dams after the end of treatment.
Overall, highly water-soluble chromium (VI) compounds should be
considered to be developmental toxicants in the mouse. These findings
can be regarded as relevant to humans. It is noted that some of the
adverse effects on reproduction observed in animal studies may be
related to the germ cell mutagenicity of these chromium (VI) compounds
(see Mutagenicity section). No reproductive toxicity studies are
available using the inhalation or dermal routes of exposure.
Human data relating to effects on reproduction are limited to poorly
reported studies of female workers from which no conclusions can be
A number of studies have been performed uisng potassium dichromate. While the studies are of non-standard design, they are considered (as a whole) to adequately assess developmental toxicity. The results of the studies are applicable to all of the water-soluble hexavalent chromium compounds in this group.
No studies of the developmental toxicity of chromium (VI) trioxide
have been idenitfied, however a number of studies performed with
potassium dichromate are available. Once systemically absorbed, the
toxicokinetics and toxicodynamics of chromium (VI) trioxide and the
other water-soluble Cr (VI) salts are essentially identical, therefore
the results of these studies are relevant and can be extrapolated.
The available studies investigated both reproductive developmental
toxicity endpoints and are discussed above.
Overall, highly water-soluble chromium (VI) compounds should be
considered to be developmental toxicants in the mouse. These
findings can be regarded as relevant to humans
Chromium trioxide is listed on Annex I of Directive 67/548/EEC with R62
classification (reproductive toxicity Category 3).
Sodium chromate, sodium dichromate and potassium dichromate are listed on
Annex I of Directive 67/548/EEC with R60 and R61 (reproductive toxicity
Category 2) classification. No changes to these classifications are
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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