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EC number: 939-967-7
CAS number: -
Effects on fertility: via oral route:
No data are available on the toxicity of erbium zirconium oxide to reproduction. One study exists with the read across substance zirconium acetate. Rossiello (2013) performed a combined repeated dose toxicity study with reproduction/developmental toxicity screening via the oral route in rats according to OECD guideline 422 (GLP). A NOAEL >= 1000 mg/kg bw/day was obtained (based on anhydrous zirconium acetate). Based on these data and the fact that erbium oxide is not classified for reproductive toxicity either, it can be concluded that erbium zirconium oxide is also unhazardous to reproduction.
The overall results of the test formulation
analyses were within the limits of acceptance for concentration (15% of
the theoretical concentration).
Effects on fertility - via oral route
No information on the potential effects of erbium zirconium oxide on reproduction is available. Because erbium oxide, according to the read across justification attached to IUCLID Section 13, is not expected to affect the toxicological properties of zirconium dioxide (the main component in the crystal lattice of erbium zirconium oxide), data on zirconium dioxide can be used for endpoint coverage. However, since no data on zirconium dioxide are available either, read across data are used from zirconium acetate, a water soluble zirconium compound, supported by the read across justification as included in the zirconium dioxide registration dossier.
The systemic toxic effects of the read across substance zirconium acetate after repeated oral dosing, as well as any toxic effects on reproduction and development, were investigated in Sprague Dawley rats up to early lactation (day 4 post partum) by Rossiello (2013). The study was performed according to OECD guideline 422 and under GLP principles.
Three groups of 10 males and 10 females each received the test item, by oral gavage, at 100, 300 and 1000 mg anhydrous zirconium acetate/kg bw/day. A similar constituted control group received the vehicle alone during the treatment period. The overall dosing period was 32 days for males, which included 2 weeks before pairing and continuously thereafter up to the day before necropsy, and up to 50 days for females, including 2 weeks before pairing and thereafter during pairing, gestation and lactation periods until day 3 post partum.
The parental animals were followed for daily clinical signs, weekly body weight, food consumption, neurotoxicity assessment, oestrous cycle, mating performance, clinical pathology evaluation including haematology and clinical chemistry, and offspring delivery. A detailed macroscopic examination, determination of organ weights, and histopathological examination, including the spermatogenic cycle, were performed. Pups were also checked for sex, body weight, clinical signs and macroscopic observations.
No mortality occurred in the study. No treatment related findings were observed either during the in vivo phase or at post mortem examination of parent animals. Microscopically, a treatment related finding was seen in males receiving 300 and 1000 mg zirconium acetate/kg bw/day consisting of minimal focal vacuolation of squamous epithelium (limiting ridge) of the non-glandular region of the stomach. This change may be attributed to a local irritant effect of the compound administered by oral gavage and since humans do not have a forestomach or structural analogue to the forestomach, this finding is not considered of toxicological relevance. In addition, no abnormalities were found during the evaluation of the spermatogenic cycle. No treatment related effects were observed in the number of oestrous cycle, pre-coital intervals, copulatory and fertility indices between treated and control groups. No significant differences were observed in the number of implantations, corpora lutea, total litter size, pre-implantation loss, pre-birth loss and gestation length between control and treated groups.
No effects were noted on reproduction and development at any dose. On the basis of the results obtained in this study, the NOAEL for reproduction/developmental toxicity was considered to be >= 1000 mg/kg bw/day (expressed as anhydrous zirconium acetate), i.e., the highest dose tested.
Taking into account the concept of the more water soluble is the substance the higher is its potential for systemic bioavailability, it can be concluded that reproduction/developmental toxicity (if any) after repeated oral exposure to zirconium dioxide (an insoluble zirconium substance) will be of even lower concern than for zirconium acetate.
Based on all information available (OECD 422 test with zirconium acetate yielding a NOAEL >= 1000 mg/kg bw/day) zirconium dioxide was concluded not to be classified as toxic for reproduction. Since erbium oxide is, according to the read across approach, not expected to alter the toxicological properties of zirconium dioxide, erbium zirconium oxide can also be concluded not to be classified as toxic for reproduction.
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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