Matte, nickel

Endpoint summary

Description of key information

The results of seven guideline-based, GLP studies recently conducted by Eurofins Product Safety Laboratory (EPSL, 2009d-j) conclude that Ni matte is not an eye or skin irritant.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Nickel matte has a harmonized EU CLP classification. Ni matte does not carry a classification for irritation or corrosion in the 1st ATP to the CLP Regulation. To confirm this classification and determine if any additional classifications may be warranted, toxicological testing results were identified and assessed. In addition, the UVCB classification was calculated by applying the CLP mixture rules based on the classification of the known or worst-case speciation of each constituent and worst-case constituent concentration in the UVCB (i.e. the maximum value of the typical concentration reported by the individual legal entities), using the MeClas tool. 

Information characterizing the potential for nickel matte to cause irritation/corrosion generally indicates that the compound is only slightly or mildly irritating. This indication is based on the results of seven guideline-based, GLP studies recently conducted by Eurofins Product Safety Laboratory (EPSL, 2009a-i) evaluating eye and skin irritation potential. The nickel matte samples tested represented a range of compositions with regards to concentrations of constituent substances across all nickel matte groups. Read-across within these groups is justified as each composition within each group has the same mineralogy and very similar compositions, with the compositions within each group differing only for classification purposes by the level of cobalt. Since cobalt levels are low (e.g. <=6%) in all compositions, and cobalt does not contribute to the classification of this endpoint, read-across within each group is justified for this endpoint. In addition, nickel matte is not classified by the MeClas tool considering the mixtures rules and the constituent classifications. As Ni matte is considered a UVCB with variable composition, the availability of reliable data on multiple samples, along with mixtures rules calculations, can be combined to provide important information regarding the potential of nickel mattes to cause skin and eye irritation. 

Three skin irritation studies were conducted in rabbits according to OECD Test #404 - Acute Dermal Irritation/Corrosion guidelines. Three healthy female rabbits were exposed via the skin to a nickel matte sample from each group to determine if the test substance had the potential to produce irritation. In each of these studies, there was no edema observed at any treated site during this study. Within one hour of patch removal, all three treated sites in all studies exhibited very slight erythema. The overall incidence of irritation decreased with time. All animals were free of dermal irritation by 24-48 hours. The Primary Dermal Irritation Index for Nickel matte was found to be 0.4, 0.3, and 0.1 (for EPSL 2009d-f, respectively). According to OECD Test #404 guidelines, compounds should be considered an irritant if responses persist to the end of the observation period; however, findings of this study indicated effects were fully reversible significantly prior to the end of the study period (Day 7).

Three eye irritation studies were also conducted in rabbits according to OECD Test #405 -Acute Eye Irritation/Corrosion guidelines. In these studies, a nickel matte sample from each group was instilled into the right eye of three healthy female rabbits to determine the potential to produce irritation. The left eye remained untreated and served as a control. Ocular irritation was evaluated by the method of Draize et al. In the first study (EPSL 2009g), all three treated eyes exhibited minimal conjunctivitis within 24 hours after test substance instillation. Observations from the second study (EPSL 2009h) indicated that one hour after test substance instillation, all three treated eyes exhibited conjunctivitis and two treated eyes exhibited iritis. By 24 hours, corneal opacity also developed in one animal. Similar findings were noted in EPSL (2009i) in which no iritis was observed in any treated eye during this study. However, one hour after test substance instillation, two treated eyes exhibited conjunctivitis. By 24 hours, corneal opacity also developed in one animal. In all three studies, the overall incidence and severity of irritation decreased with time and all animals were free of ocular irritation by 48-72 hours. The results of the study indicated that nickel matte was mildly or minimally irritating to the eye under the conditions of the studies. The OECD Test #405 guidelines state that extrapolation of these results to humans is only valid to a limited degree as in many cases the albino rabbit is more sensitive than humans to ocular irritants for corrosives.

Nickel matte is not classified for irritation by the MeClas tool considering mixtures rules and elemental speciation. 

Collectively, these in vivo tests and MeClas calculation provide reliable, adequate information to assess the irritant/corrosive properties of nickel matte. The in vivo studies were specifically designed to evaluate the health hazard likely to arise from exposure by dermal or ocular application. Results demonstrated that nickel matte can cause minor irritation in laboratory settings. However, all observed effects were fully reversible and generally classified as “slight”, “minimal” or “mild,” thus indicating a limited potential for irritant/corrosive potential. In addition, nickel matte was not predicted to be irritating or corrosive by mixtures rules calculations.

The following information is taken into account for any hazard / risk assessment:

Nickel matte has a harmonized EU CLP classification. Nickel matte does not carry a classification for irritation or corrosion in the 1st ATP to the CLP Regulation. The results of six guideline-based, GLP studies recently conducted by Eurofins Product Safety Laboratory (EPSL, 2009d-i) and MeClas calculations (ARCHE 2015) conclude that Ni matte is not an eye or skin irritant.

Value used for CSA:

Skin irritation / corrosion: No adverse effect observed (not irritating)

Eye irritation / corrosion: No adverse effect observed (not irritating)

Justification for classification or non-classification

Ni matte is not classified for skin or eye irritation in the 1st ATP to the CLP. The results of the studies summarized above provide sufficient support for non-classification.

·   See furthermore attached documents:

Please refer to IUCLID section 13 or CSR Appendix I for detailed MeClas printouts with the specified input concentrations and resulting classification. Please visit www.meclas.eu for more information about the tool.