Nickel(2+) hydrogen citrate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Additional information:

There are no skin sensitisation studies for [citric acid, nickel salt]. However, extensive data exist for the read-across substance nickel sulphate.

Parts of the data are taken from the EU-RAR for nickel sulphate, dated 2008.

 

A number of studies on skin sensitisation have been performed with nickel sulphate in guinea pigs and mice.

In a modified guinea pig maximization test (GPMT), nickel sulphate produced positive reactions in all tested animals at an induction concentration of 1% and challenge concentrations of 5, 2 and 1% (Ikarashi et al. 1996). Ikarashi et al. (1992) also showed the sensitising potential of nickel sulphate (10% solution) in a local lymph node assay (LLNA) conducted similar to OECD guideline 429. Furthermore, the same authors performed a sensitive mouse lymph node assay with nickel sulphate. In this assay, the intradermal treatment with a 2% solution and the topical application of a 5% solution resulted in a total stimulation index of 24.08.

In contrast, a LLNA performed with nickel sulphate solutions of up to and including 5% did not produce a positive response in the test animals (Ikarashi et al. 1992). Ambiguous results were reported in an interlaboratory validation study (Omori et al. 2008).

 

In conclusion, reliable studies using different protocols, either GPMT or LLNA, demonstrated that nickel sulphate is a skin sensitiser in guinea pigs and mice. In addition, numerous human data also show that soluble nickel salts are skin sensitisers (refer to EU RAR).

Migrated from Short description of key information:
The read-across substance nickel sulphate was sensitising in the guinea pig maximization test as well as in the local lymph node assay. Based on the analogy approach, the substance [citric acid, nickel salt] is also expected to be a skin sensitiser.

Respiratory sensitisation

Endpoint conclusion

Additional information:

There are no animal data on respiratory sensitisation for [citric acid, nickel salt]. However, human case reports exist for the read-across substance nickel sulphate.

 

The available case reports (cited in the EU RAR for nickel sulphate, 2008) support the hypothesis that soluble nickel salts are capable of inducing hypersensitive reactions in the respiratory tract, e. g. asthma and/or rhinitis, after inhalation exposure (Block et al. 1982, Malo et al. 1982, Malo et al. 1985, McConnell et al. 1973, Novey et al. 1983, Niordson 1981).

 

References:

Block GT, Yeung M (1982): Asthma induced by nickel. JAMA 24711: 1600-1602.

Malo JL, Cartier A, Doepner M, Nieboer E, Evans S, Dolovich J. (1982): Occupational asthmatic caused by nickel sulphate. J. Allergy Clin. Immunology 69: 55-59.

Malo JL, Cartier A, Gagnon G, Evans S, Dolovich J. (1985): Isolated late asthmatic reaction due to nickel sulphate without antibodies to nickel. Clinical allergy 15: 95-99.

McConnell LH, Fink JN, Schlueter DP, Smith MG (1973): Asthma caused by nickel sensitivity. Annals of internal medicine 78: 888-890.

Niordson AM (1981): Nickel sensitivity as a cause of rhinitis. Contact dermatitis 7: 73-74.

Novey HS, Habib M, Wells ID (1983): Asthma and IgE antibodies induced by chromium and nickel salts. J.Allergy Clin. Immunol 72: 407-412.

Migrated from Short description of key information:
Case reports evidence the respiratory sensitisation by nickel sulphate in humans. Based on the analogy approach, the substance [citric acid, nickel salt] is also expected to be a respiratory sensitiser.

Justification for classification or non-classification

Based on the available data, the substance [citric acid, nickel salt] needs to be classified:

EU: R42/43

CLP: Category 1 respiratory sensitisation/ category 1 skin sensitisation