Barium sulphide

Endpoint summary

Key value for chemical safety assessment

Skin sensitisation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not sensitising)

Additional information:

Testing with a corrosive substance is not allowed due to animal welfare and in accordance with section 8.3, column 2, Annex VII of regulation (EC) 1907/2006). Since barium sulfide was tested to be corrosive to skin with a pH value of 13.0 (1% solution), testing is not justified.

Nevertheless, the sensitisation potentialmay reasonably be considered by the availability of barium cations and sulfide anions.

 

Barium:

Upon dissolution in water and/or physiological media, dissociation to barium sulfide to release Ba²⁺ions may initially be expected.

 

However, based on the established fact that barium ions may form poorly soluble species for example with physiologically present carbonate ions, the bioaccessibility/bioavailability may vary between different physiological conditions. Notwithstanding this limitation, it is considered justified to read-across from available data either on barium hydroxide (similar water solubility) and/or barium chloride (higher water solubility), the latter representing a conservative approach). In this context, the water solubility of a substance is used as a first approximation of bioavailability:

 

- barium chloride is highly water soluble with ca. 375 g/L at 20°C/pH ca. 6.5 (510.4 g/L at pH 1.5)

- barium hydroxide is also highly water soluble (37.4 g/L at 20°C/pH > 13).

 

In comparison, the water solubility of barium sulfide is given with 73.5 g/L at 20°C (pH 13.7; saturated solution).

 

In conclusion, read across from barium chloride and barium hydroxide to barium sulphide is considered as justified.

 

Sulfides: Sulfides may be seen as ions endogenously occurring under physiological conditions, so that their role in normal human metabolism suggests that a sensitisation potential does not necessarily need to be expected.

 

In addition it could be stated that long time experience in handling with barium substances and sulfides does not show any sensitising effects in humans.

Summarising that the LLNA study conducted with barium dichloride dihydrate causes no sensitising effects to skin and read across to soluble barium substances (i.e., barium dichloride) is justified, a sensitisation potential for barium sulfide can safely be excluded.

Migrated from Short description of key information:
No data are available on skin sensitisation of barium sulfide. As barium sulfide is classified for skin corrosivity and has a pH value 13.0 (1% solution) no testing needs to be initiated. However, testing with barium dichloride dihydrate was conducted and study result indicates that the test item is considered not to be skin sensitising.

Respiratory sensitisation

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the outcome of the sensitisation study according OECD 429 conducted with barium dichloride dihydrate and under consideration of read-across (see discussion) it can be concluded that barium sulfide 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.