Ammonium trioxovanadate

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Soluble tetra- and pentavalent vanadium substances failed to elicit any skin sensitising response in sensitisation studies according to Magnusson and Kligman (OECD 406). The studies by Haferkorn (2010a,b) are considered key studies on skin sensitisation and are used for classification. Positive human experience with any vanadium substance have not been reported. Based on read-across, ammonium trioxovanadate is not assumed to have a potential for skin sensitisation.

Read across

Upon dissolution, vanadium substances transform inartificial body fluids, including PBS, sweat, gastric juice and lung fluid, predominantly to the pentavalent form,except in artificial lysosomal fluid; here, even pentavalent forms are converted almost completely to tetravalent species already after a short period of time (for more information on in vitro bioaccessibility testing, please refer IUCLID section 7). Thus, it can be assumed that vanadium speciation in body fluids is controlled by the conditions of the respective medium but not by the vanadium source. Thus, read-across of skin sensitisation data from soluble tetra- and pentavalent vanadium substances is justified.

Ammonia/ammonium (i) is ubiquitous in the environment (air, soil and water) and as part of the natural nitrogen cycle intrinsically present in the human body due to a natural background in all dietary sources, and (ii) ammonia/ammonium is a normal constituent of all body fluids. The sources of endogenous ammonium include bacterial hydrolysis of urea and other nitrogenous compounds in the intestine, the purine-nucleotide cycle, amino acid transamination in skeletal muscle, and other metabolic processes in kidneys and liver. At physiological pH, it exists mainly as ammonium ion with reference serum levels just below 35 µmol/L. Any excess ammonia is excreted as urea, which is synthesised in the liver through the urea cycle. In consequence, because of its intrinsic nature as an endogenous physiological compound, any skin sensitising effect of ammonium is not to be expected. Therefore, only the potential of the respective vanadium anion was addressed by testing.

Migrated from Short description of key information:
Soluble penta- and tetravalent vanadium substances did test negative (i.e. not sensitising) in skin sensitisation studies according to Magnusson and Kligman (OECD 406). A justification for using the Magnusson and Kligman design instead of the LLNA is provided as attached document below. Ammonium trioxovanadate is not considered to have a sensitisation potential.

Justification for selection of skin sensitisation endpoint:
The studies by Haferkorn (2010a,b) are considered key studies on skin sensitisation and used for classification.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Migrated from Short description of key information:
Vanadium exposure has not been reported to induce immune responses in vanadium industry workers, and occupational asthma or reduced lung function has not been diagnosed in vanadium and vanadium substances producing facilities.

Justification for classification or non-classification

Based on the outcome of sensitisation studies with soluble tetra- and pentavalent vanadium forms according to Magnusson and Kligman, it can be concluded that ammonium trioxovanadate does not have a sensitisation potential and therefore must not be classified and labelled according to Directive 67/548/EEC and Regulation (EC) 1272/2008.