Reaction mass of cerium dioxide and lanthanum oxide and lanthanum fluoride

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Additional information

No study is available for the reproductive and developmental effects of the reaction mass of Cerium dioxide and Lanthanum oxide and Lanthanum fluoride. However, due to similar physico-chemical, toxicological, ecotoxicological and environmental properties, data on main constituents as cerium dioxide and lanthanum oxide are considered in a weight-of-evidence approach to conclude on the reproductive toxicity of the reaction mass of Cerium dioxide and Lanthanum oxide and Lanthanum fluoride.

Reproductive toxicity studies on the reaction mass of Cerium dioxide and Lanthanum oxide and Lanthanum fluoride are therefore not regarderd as scientifically necessary according to section 1 of Reach Annex XI and is not recommended under animal protection considerations.

Cerium dioxide

The potential reproductive toxicity of cerium dioxide was tested in rats in an OECD TG 422 GLP-compliant study (Klimisch 2) following daily oral gavage from 2 weeks before mating, through mating and, for the females, through gestation until day 5post partum, at dose levels up to 1000 mg/kg (CIT, 2010). There were no relevant differences from controls for pairing, mating, fertility and delivery parameters. Macroscopic and microscopic examinations at necropsy did not reveal any treatment-related findings or organ weight changes in reproductive organs.The NOEL for reproductive performance was therefore 1000 mg/kg, a limit dose for repeated-dose toxicity, illustrating the absence of reproductive toxicity of cerium dioxide.

Furthermore, there were no adverse effects on the reproductive organs of rats exposed by inhalation for 90 days to cerium dioxide up to the very high concentration of 507.5 mg/m3 (see section '7.5.3 Repeated dose toxicity: inhalation' for details). There were no relevant changes in the weight of gonads, prostate or uterus. No macroscopic abnormalities of the reproductive organs were observed at necropsy. There were no relevant histopathological findings at the microscopic examination of epididymides, testes, prostate, ovaries or uterus in any group.

Lanthanum oxide

Hutcheson et al. (1975) fed a diet containing 0, 0.4, 4, 40 and 400 ppm lanthanum oxide (equivalent to 0.69,1.16,6.08, 62.5 and 650 µg lanthanum/kg) and other metal oxides to male and female CF-1 mice for three generations. In all generations, no exposure-related effects on reproduction (pregnancy rate and average litter size as well as lactation) were observed.

 

Toxicity to reproduction	Reaction mass	Cerium dioxide	Lanthanum oxide	Lanthanum fluoride
Effects on fertility/development	-	NOAEL > 1000 mg/kg bw/d	No reproductive effects in a mouse three-generation study	-
Further information	-	No effects on reproductive organs up to 507,5 mg/m3 in a 90-day rat inhalation study	-	-

 

Short description of key information:
No reproductive toxicity was observed in an OECD TG 422 GLP-compliant study in rats performed by oral route with cerium dioxide, the majority constituent of the reaction mass of cerium dioxide and lanthanum oxide and lanthanum fluoride. In addition, lanthanum oxide, another main constituent of the reaction mass, induced no reproductive or developmental toxic effect in a three-generation study in mice by dietary administration.
Furthermore, no effect on reproductive organs were observed in repeated inhalation studies performed with the majority constituent of the reaction mass, cerium dioxide (90 day-inhalation study in rat; Viau A. Bio-Research Laboratories, 1994).

Effects on developmental toxicity

Description of key information

No developmental toxicity observed in an OECD TG 422 GLP-compliant study in rats performed with cerium dioxide, the majority constituent of the reaction mass of cerium dioxide and lanthanum oxide and lanthanum fluoride. In addition, lanthanum oxide, another main constituent of the reaction mass, induced no developmental toxic effect in a three-generation study in mice by dietary administration.

Additional information

No study is available for the reaction mass of Cerium dioxide and Lanthanum oxide and Lanthanum fluoride, neither on the individual constituents.

However, the performance of an OECD TG 414 study on the reaction mass of Cerium dioxide and Lanthanum oxide and Lanthanum fluoride appears inadequate based on:

- available data on its two main constituents, cerium dioxide and lanthanum oxide, which show similar physicochemical and toxicological properties,

- the absence of any reproductive alert in the OECD 422 screening study in rats performed with cerium dioxide up to the limit dose of 1000 mg/kg bw orally,

- the absence of any reproductive alert in the thre-generation study in mice performed with lanthanum oxide following dietary administration,

- the absence of adverse effects on the reproductive organs in the 90-day rat inhalation study on cerium dioxide up to the very high concentration of 507.5 mg/m3,

- the expected very low bioavailability of these chemicals due to their insoluble and inorganic nature.

Justification for classification or non-classification

No classification for reproductive or developmental toxicity is warranted for the reaction mass of Cerium dioxide and Lanthanum oxide and Lanthanum fluoride according to the criteria of Annex VI Directive 67/548/EEC or UN GHS/EU CLP based on the absence of relevant effects in studies performed on its main constituents.