Barium

Endpoint summary

Description of key information

Barium metal reacts with water to form the Ba(OH)2, which is a strong base that dissociates completely into Ba2+ and OH- ions, with resulting high pH level in solution (pH> 11 at 1 mM). Because barium metal reacts with water into barium dihydroxide and thus into a strong base, studies on skin and eye irritation should not be conducted: for this reason, barium (because of its reactivity and formation of barium dihydroxide)meets the classification criteria of Regulation (EC) no 1272/2008 for Skin Corrosion Category 1 (H314: causes severe skin burns and eye damage) and Eye Damage Category 1 (H318: Causes serious eye damage).

Because the hydroxyl ions will be quickly neutralised, the assessment of barium metal is based on Barium-ion assessment, except for acute and local human health effects, which will be driven by the pH effects.

Information available from the BaCl2 REACH Dossier: an in vitro skin irritation study (EpiSkinTM) and an in vivo eye irritation study (OECD 405) were performed with barium dichloride dihydrate, which indicated that the test substance is not irritating to the skin but irritating to the eyes.

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Ba2+ data from BaCl2 REACH Dossier is analysed.

Skin irritation:
Reference Verbaan (2010) is considered as the key studies for in vitro skin irritation and will be used for classification. The overall irritation result is as follows:

Relative viability: mean after 15 min incubation 80% (max. score: 88%); evaluated by MTT reduction.

 

Eye irritation:

Reference Stitzinger (2010) is considered as the key study for eye irritation and will be used for classification. The overall irritation results are as follows:

Corneal opacity, iritis, chemosis and conjunctivae, 24, 48 and 72h after application: max score=3; effects were reversible within 21 days

Justification for selection of skin irritation / corrosion endpoint:
GLP guideline study of 2010

Justification for selection of eye irritation endpoint:
GLP guideline study of 2010

Effects on eye irritation: irritating

Justification for classification or non-classification

Ba2+ data from BaCl2 REACH Dossier is analysed.

Barium is classified as Corrosive Cat 1 and Eye Damage Cat 1.

Hereby, a summary from BaCl2 REACH Dossier is given

Skin irritation:

Reference Verbaan (2010) is considered as the key studies for in vitro skin irritation and will be used for classification. The overall irritation result is as follows:

Relative viability: mean after 15 min incubation 80% (max. score: 88%); evaluated by MTT reduction.

 

The classification criteria according to regulation (EC) 1272/2008 as irritating to skin are not met since the mean rel. viability is >50% of the control, hence no classification required. The in vitro study according to the draft EC method B.46 (EpiSkin^TM) was validated and considered of being a reliable and relevant stand-alone test for predicting rabbit skin irritation, and for being used as a replacement of in vivo method OECD 404 for the purposes of distinguishing between R38 skin irritating and non-skin irritating test substances (ECVAM, 27.04.2007).

 

 

Eye irritation:

Reference Stitzinger (2010) is considered as the key study for eye irritation and will be used for classification. The overall irritation results are as follows:

Corneal opacity, iritis, chemosis and conjunctivae, 24, 48 and 72h after application: max score=3; effects were reversible within 21 days

The classification criteria according to regulation (EC) 1272/2008 as irritating to eyes are met since the mean score after 24, 48 and 72h was > 2 for chemosis and conjunctivae, hence classification and labelling as “eye damage 1” H318 is required.

 

Respiratory irritation:

The classification as respiratory irritant is covered under the endpoint specific target organ toxicity- single exposure and repeated exposure. Please refer to the endpoint summaries on acute toxicity (endpoint 7.2) and repeated dose toxicity (endpoint 7.5) for further information.