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Administrative data

Description of key information

Acute toxicity, oral: LD50 > 2000 mg Pyrochlore/kg b.w.
Acute toxicity, inhalation: LC50 >5.11 mg/L air. (MMAD: 2.860 µm (GSD: 2.62))

Key value for chemical safety assessment

Additional information

One acute oral toxicity study according to OECD guideline 401 has been performed that will be used for classification. This study indicates that oral LD50 is >2000 mg/Kg bw in rats.

For acute inhalation toxicity there is one animal study which will be used for classification and that has been performed according to OECD TG 436 and which shows no signs of acute toxicity after inhalation exposure to pyrochlore, indicating a LC50 > 5.11 mg/L.

Slight ataxia (0 - 60 min), slight tremor (0 - 60 min) and slight dyspnoea (0 min - 3 h) were observed in all 3 male and 3 female rats.

No mortality occured.

There are no reliable reports whatsoever on acute dermal toxicity in the public domain. However, the conduct of an acute dermal toxicity study is unjustified as inhalation of the substance is considered as major route of exposure and physicochemical properties and dermal absorption data of the substance do not suggest a significant rate of absorption through the skin (cf. Annex VIII section 8.5 Column 2 of regulation (EC) 1907/2006).

Justification for classification or non-classification

Acute toxicity oral:

Under the present test conditions a single oral administration of 2000 mg Pyrochlore/kg b.w. to rats revealed no toxic symptoms. The animals gained the expected weight through the test exposure period. No abnormalities were noted at necrospy. According to the criteria specified by Directive 67/548/EEC and subsequent regulations, the test item is not classified as acute toxic by the oral route. According to the EC Regulation No. 1272/2008 and subsequent regulations, the test item is not classified as acute toxic by the oral route.

Specific target organ toxicant (STOT) – single exposure: oral

The classification criteria acc. to regulation (EC) 1272/2008 as specific target organ toxicant (STOT) – single exposure, oral are not met since no reversible or irreversible adverse health effects were observed immediately or delayed after exposure and no effects were observed at the guidance value, oral for a Category 1 classification of 300 mg/kg bw and at the guidance value, oral for a Category 2 classification of 2000 mg/kg bw. No classification required.

Acute inhalation toxicity:

The reference Haferkorn, J. is considered as key study for the endpoint acute inhalation toxicity and will be used for classification.

Under the conditions of this study, the 4-hour inhalation LC50 of Pyrochlore is >5.11 mg/L air. According to the EC Regulation 1272/2008 and subsequent regulations, the test material is not classified for acute inhalation toxicity. According to the EC-Commission directive 67/548/EEC and subsequent regulations, the test material is not classified for acute inhalation toxicity.

Specific target organ toxicant (STOT) – single exposure: inhalation

The classification criteria acc. to regulation (EC) 1272/2008 as specific target organ toxicant (STOT) – single exposure, inhalation dust/mist/fume are not met since no reversible or irreversible adverse health effects were observed immediately or delayed after exposure and no effects were observed at the guidance value, inhalation dust/mist/fume for a Category 1 classification of 1.0 mg/L/4h and at the guidance value, inhalation dust/mist/fume for a Category 2 classification of 5.0 mg/L/4h. Therefore, no classification is required.

Finally, any category 3 classification should primarily be based on human data. However, such classification is also not warranted, since observations on respiratory irritation in test animals (rats) were not observed.