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Description of key information

Key value for chemical safety assessment

Skin sensitisation

Link to relevant study records
Reference
Endpoint:
skin sensitisation: in vivo (LLNA)
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
The assessment entity approach was used for the classification of NCA; this endpoint is assessed on the basis of the toxicological properties of the relevant constituents (= assessment entities) of the UVCB.
Reason / purpose for cross-reference:
reference to same study
Qualifier:
according to guideline
Guideline:
other: CLP Regulation 1272/2008 - Annex I (mixture rules)
Principles of method if other than guideline:
The skin sensitization potential of NCA (generic worst-case composition) was determined by classifying based on Mixture rules from EU CLP.
GLP compliance:
not specified
Key result
Remarks on result:
other: A reliable assessment, based on the CLP mixture rules and using the MeClas Classification Tool, was conducted on a generic NCA sample. The assessed generic NCA composition is classified a Skin Sensitizer, Cat. 1.
Interpretation of results:
Category 1 (skin sensitising) based on GHS criteria
Conclusions:
The assessment of the skin sensitizing properties of NCA is based on the skin sensitizing properties of its constituents (oxide forms of Al, Co, Li, Ni) (Assessment Entity Approach).
A reliable assessment, based on the CLP mixture rules and using the MeClas Classification Tool, was conducted on a generic NCA sample (composition based on worst-case concentrations for each constituent, as defined in IUCLID section 1.2). The assessed generic NCA composition is classified a Skin Sensitizer, Cat. 1.

Executive summary:

The study provides a conservative estimate of the effect concentration, derived on basis of the classification outcome (mixture toxicity rules) from a reasonable worst-case sample of the substance using mineralogical information from the representative sample. 

 

Validity of the model used:

1. Defined endpoint: the endpoint is a REACH compliant defined endpoint

2. Unambiguous algorithm: EU CLP guidance based summation formula to determine classification, followed by back-calculation to related hazard criteria

3. Applicability domain: applicable to classify complex metal containing materials. 

4. Mechanistic interpretation - metal species: the tool translates the elemental composition into a mineralogical composition relevant for classification.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

A study was performed to assess the skin sensitisation potential of the test material (NCA, typical composition) in the CBA/Ca strain mouse following topical application to the dorsal surface of the ear. The method was designed to meet the requirements of the following: OECD Guideline for the Testing of Chemicals No. 429 "Skin Sensitisation: Local Lymph Node Assay" (adopted) and Method B42 Skin Sensitisation (Local Lymph Node Assay) of Commission Directive 2004/73/EC.

Following a preliminary screening test in which no clinical signs of toxicity were noted at a concentration of 25% w/w, this concentration was selected as the highest dose investigated in the main test. Three groups, each of four animals, were treated with 50 µl (25 µl per ear) of the test material as a suspension in propylene glycol at concentrations of 25, 10 or 5% w/w. A further group of four animals was treated with propylene glycol alone.

The Stimulation Index for each dose level (expressed as the mean radioactive incorporation for each treatment group divided by the mean radioactive incorporation of the vehicle control group) signified a negative result. Therefore the test material (NCA with typical concentration) was considered to be a non sensitiser under the conditions of the test.

A reliable assessment, based on the CLP mixture rules and using the MeClas Classification Tool, was also conducted on a generic NCA sample (composition based on worst-case concentrations for each constituent, as defined in  IUCLID section 1.2). The assessed generic NCA composition is classified a Skin Sensitizer, Cat. 1. It should be noted that concentration levels of critical constituents in generic NCA are higher than the concentration levels in the tested material, and it was therefore decided to retain the classification conclusion that is based on the MeClas calculation.

Respiratory sensitisation

Link to relevant study records
Reference
Endpoint:
respiratory sensitisation: in vivo
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
The assessment entity approach was used for the classification of NCA; this endpoint is assessed on the basis of the toxicological properties of the relevant constituents (= assessment entities) of the UVCB.
Reason / purpose for cross-reference:
reference to same study
Principles of method if other than guideline:
The respiratory sensitization potential of NCA (generic worst-case composition) was determined by classifying based on Mixture rules from EU CLP.
Interpretation of results:
Category 1 (respiratory sensitising) based on GHS criteria
Conclusions:
The assessment of the respiratory sensitizing properties of NCA is based on the respiratory sensitizing properties of its constituents (oxide forms of Al, Co, Li, Ni) (Assessment Entity Approach).
A reliable assessment, based on the CLP mixture rules and using the MeClas Classification Tool, was conducted on a generic NCA sample (composition based on worst-case concentrations for each constituent, as defined in IUCLID section 1.2). The assessed generic NCA composition is classified a Respiratory Sensitizer, Cat. 1.
Executive summary:

The study provides a conservative estimate of the effect concentration, derived on basis of the classification outcome (mixture toxicity rules) from a reasonable worst-case sample of the substance using mineralogical information from the representative sample. 

 

Validity of the model used:

1. Defined endpoint: the endpoint is a REACH compliant defined endpoint

2. Unambiguous algorithm: EU CLP guidance based summation formula to determine classification, followed by back-calculation to related hazard criteria

3. Applicability domain: applicable to classify complex metal containing materials. 

4. Mechanistic interpretation - metal species: the tool translates the elemental composition into a mineralogical composition relevant for classification.

Endpoint conclusion
Endpoint conclusion:
adverse effect observed (sensitising)
Additional information:

A reliable assessment, based on the CLP mixture rules and using the MeClas Classification Tool, was also conducted on a generic NCA sample (composition based on worst-case concentrations for each constituent, as defined in  IUCLID section 1.2). The assessed generic NCA composition is classified a Respiratory Sensitizer, Cat. 1. It should be noted that concentration levels of critical constituents in generic NCA are higher than the concentration levels in the tested material, and it was therefore decided to retain the classification conclusion that is based on the MeClas calculation.

Justification for classification or non-classification

In accordance with the criteria for classification of mixtures as defined in Annex I, Regulation 1272/2008, the test material is classified as Skin/Resp. Sensitizer, Cat.1.