ALFERROCK

Endpoint summary

Description of key information

No studies conducted with target substance on irritation/corrosion are available.

According to the results of specific bioelution testing with the test substance (Klawonn, 2021, please see IUCLID section 7.1.1), aluminium has the highest relative release into artificial physiological media representing relevant exposure routes and therefore was considered as main constituent for the human health hazard/risk assessment of the substance "Neutralisation and reduction products of bauxite residue from refinement process.

Aluminium ions show very low release in the Artificial sweat solution (33.2 µg/g of Alferrock/liter within 2h and 150.3 µg/g of substance/liter after 24 hours, see IUCLID section 7.1.1). Considering the limited elution of Al into such artificial physiological media as artificial sweat solutions and phosphate buffered saline it could be assumed that Al remains bound in the particles and could not cause such local effects as irritation or corrosion. Therefore, it can be assumed that no local effects would be expected at such a low concentration of bioaccessible aluminium released from of the substance.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no study available

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

For human health endpoints, the relative bioavailability of different metal-ions from the substance "Neutralisation and reduction products of bauxite residue from refinement process" would determine its potential to cause toxicological effects and also govern the severity of such effects. The dissolution rate of the substance in artificial physiological fluids, including Artificial gastric fluid (pH = 1.5), Phosphate buffered saline (pH = 7.4), Gamble´s solution (pH = 7.4), Artificial lysosomal fluid (pH = 4.5) and Artificial sweat solution (pH = 6.5) was investigated by Klawonn et al. (2021b, see IUCLID section 7.1.1). Based on this approach, release rates of metal ions at the sites of first contact for the human-relevant exposure routes can be simulated.

According to the results of the bioelution testing, aluminium has the highest relative release into artificial physiological media and therefore was considered as main constituent for the human health hazard/risk assessment of the substance. Release of aluminium into Artificial sweat solution (pH = 6.5) simulates an exposure scenario in contact with human skin. Aluminium ions show very low release in the Artificial sweat solution (33.2 µg/g of test item/liter within 2h and 150.3 µg/g of test item/liter after 24 hours, see IUCLID section 7.1.1). Similarly, PBS (pH 7.4) can be regarded as a surrogate for the conditions upon ocular contact. Aluminium ions show very low release in PBS at rates of 11.6 µg/g test item and 71.5 µg/g test item after 2h and 24 h, respectively. Aluminium can therefore be considered practically insoluble under conditions of dermal and ocular exposure.

Considering this very limited elution of aluminium into artificial sweat and PBS solutions it could be assumed that aluminium remains bound in the matrix of "Neutralisation and reduction products of bauxite residue from refinement process" and would not be locally accessible to penetrate the skin barrier or cause local effects, such as irritation or corrosion. Therefore, it can be assumed that no local effects would be expected at such a low concentration of bioaccessible aluminium upon skin and eye contact with the substance. Conducting a study on skin irritation/corrosion and eye damage/irritation is therefore considered to be scientifically unjustified.

Justification for classification or non-classification

According to the results of the bioelution testing (see IUCLID section 7.1.1), aluminium has the highest relative release into artificial physiological media and therefore was considered as main constituent for the human health hazard/risk assessment of "Neutralisation and reduction products of bauxite residue from refinement process". For details and justification of read-across please refer to the report attached in section 13 of IUCLID.

Considering the limited elution of Al into such artificial physiological fluids as Artificial sweat solutions and Phosphate buffered saline, it could be assumed that aluminium remains bound in the particles and could not cause such local effects as irritation or corrosion. Therefore, classifications for skin irritation/corrosion or eye irritation according to the criteria of Annex I of Regulation (EC) 1272/2008 (CLP Regulation) are not warranted.