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Effects on fertility

Effect on fertility: via oral route
Dose descriptor:
NOAEL
63 mg/kg bw/day
Additional information

No studies on reproductive toxicity of zinc tetraoxychromate have been found. Data on highly soluble chromates show a varying range of effects on fertility or development. Soluble chromates (potassium dichromate, sodium chromate, sodium dichromate and ammonium dichromate) are classified for reproductive toxicity (Repr. 1B) in EU.

A well-conducted 2-generation continuous breeding study (NTP 1997) with mice did not show any significant fertility effects even at the highest concentration of potassium dichromate (up to 30 mg Cr(VI) /kg/day). The second relevant study described in the assessment (Junaid et al. 1996b) showed a NOAEL of 63 mg Cr(VI) /kg/day for fertility effects. The other studies focused mainly on effects on testes and ovaries and did not reveal direct fertility effects.

Although there is no specific information on the toxicokinetics of zinc tetraoxychromate, the available data on other sparingly soluble chromates suggest that chromates can enter the body via inhalation or at lesser extent via gastrointestinal tract (see Toxicokinetics). Therefore, the reprotoxic risk of these chromates cannot be excluded.

REACH Technical Guidance (R.7.6.6.3 Testing strategy for reproductive toxicity): If the substance is classified as a genotoxic carcinogen (Carcinogen Cat 1 and Mutagen Cat 3 or Carc Cat 2 and Mutagen Cat 3) or a germ cell mutagen (Mut Cat 1 or Cat 2).... it is important to establish that appropriate risk management measures addressing potential carcinogenicity, genotoxicity or reproductive toxicity have been implemented and therefore further specific testing for reproductive and/or developmental toxicity will not be necessary.

In this assessment, zinc tetraoxychromate is proposed to be classified for carcinogenicity and mutagenicity. Thus no further testing for reproductive effects is suggested.

The DNEL that can be derived for Cr(VI) reproductive toxicity in the CSR (0.02 mg Cr(VI) /m3) is significantly higher than the DMEL suggested for carcinogenicity (0.5 µg/m3). Therefore, the risk management measures proposed due to the carcinogenicity DMEL are also appropriate for reproductive toxicity risks.


Short description of key information:
No studies on reproductive toxicity of zinc tetraoxychromate have been found. Data on highly soluble chromates show a varying range of effects on fertility. Soluble chromates (potassium dichromate, sodium chromate, sodium dichromate and ammonium dichromate) are currently classified for reproductive toxicity (Repr. 1B) in EU.

Effects on developmental toxicity

Description of key information
No studies on reproductive toxicity of zinc tetraoxychromate have been found. Data on calcium chromate or highly soluble chromates show a varying range of effects on fertility or development. Soluble chromates (potassium dichromate, sodium chromate, sodium dichromate and ammonium dichromate) are classified for reproductive toxicity (Repr. 1B) in EU.
Effect on developmental toxicity: via oral route
Dose descriptor:
LOAEL
20 mg/kg bw/day
Additional information

No studies on reproductive toxicity of zinc tetraoxychromate have been found. Data on calcium chromate or highly soluble chromates show a varying range of effects on fertility or development. Soluble chromates (potassium dichromate, sodium chromate, sodium dichromate and ammonium dichromate) are classified for reproductive toxicity (Repr. 1B) in EU.

Indirect exposure of foetuses via the placenta is possible and thus exposure should be avoided during pregnancy.

Effects on development (including increased post-implantation losses and resorptions, significant reductions in foetal weight and crown-rump length, increased incidences of kinky tail, subdermal hemorrhagic patches, reduced foetal cranial and bone ossification, drooping of the wrist (carpal flexure) and/or streak on the snout, limbs, back, neck and tail) have been observed at dose levels starting from 20 mg Cr(VI) /kg/day.

Justification for classification or non-classification

Zinc tetraoxychromate is suggested to be classified for reproductive toxicity as Category 2 based on weight of evidence. The substance is also classified as carcinogenic and mutagenic and no further testing for this endpoint is suggested.

(REACH Technical Guidance (R.7.6.6.3 Testing strategy for reproductive toxicity): If the substance is classified as a genotoxic carcinogen (Carcinogen Cat 1 and Mutagen Cat 3 or Carc Cat 2 and Mutagen Cat 3) or a germ cell mutagen (Mut Cat 1 or Cat 2).... it is important to establish that appropriate risk management measures addressing potential carcinogenicity, genotoxicity or reproductive toxicity have been implemented and therefore further specific testing for reproductive and/or developmental toxicity will not be necessary).