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Toxicological information

Carcinogenicity

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Description of key information

According to the NTP study performed 1994, the concentration of 2500 ppm represents a NOAEL for carcinogenicity (corresponding to Ba doses of 60 and 75 mg/kg bw/d to male and female rats, respectively, and 160 and 200 mg/kg bw/d to male and female mice, respectively). Based on this value the NOAEL for Ba(OH)2 is calculated at 75 mg/kg bw/day.

Key value for chemical safety assessment

Additional information

Read across BaCl2*2H2O to Ba(OH)2:

The toxicity of barium hydroxide and barium chloride may reasonably be considered to be determined by availability of Ba2+cations. As a first surrogate for bioavailability, the water solubility of a test substance may be used. Barium chloride is highly water soluble with ca. 263 g/L at pH ca. 6.5 (510.4 g/L at pH 1.5). Also the water solubility of barium hydroxide is high (37.4 mg/L at pH > 13). Hence, any read across from barium chloride to barium hydroxide is considered to be justified and will likely lead to rather conservative no-effect levels.It is noted; although Ba(OH)2is a strong base (pH 13 for a 10% solution) it will be neutralised within the gastrointestinal tract (pH approx. 1.5 - 2).

Justification for classification or non-classification

There was no evidence of carcinogenic activity (showing no chemical related increase of malignant or benign neoplasms) of barium chloride in both sexes of rats and mice that received 500, 1250, and 2500 ppm. Thus, the concentration of 2500 ppm represents a NOAEL (corresponding to barium doses of 60 and 75 mg/kg bw/d to male and female rats, respectively, and 160 and 200 mg/kg bw/d to male and female mice, respectively). No classification of the substance as CMR substance is required.