Cobalt(2+) disulphamate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Read-across from soluble cobalt substances (i.e., cobalt dichloride and cobalt sulfate) and sodium sulfamate to cobalt(2 +) disulfamate is performed. A detailed documentation on read-across is attached on IUCLID section 13 (CoSulf_Read Across Assessment Framework Report).

Sodium sulfamate:

An Ames test according ot OECD 174 was performed in 2011. There were no biologically significant increases in the frequency of revertant colonies recorded.

Soluble cobalt substances *:

Bacterial test systems (required Annex VII):

Two published reports showing weak evidence for mutagenic activity of cobalt chloride and cobalt sulfate are available. Therefore, a series of GLP studies were performed using the bacterial strains that had shown evidence of potential mutagenic effects: cobalt chloride was tested in strain TA97a and cobalt sulfate was tested in strain TA100. The studies were performed in two different laboratories using an identical study design. In both laboratories, there was no evidence of any increases in revertant numbers with any of the test chemicals under any of the treatment conditions, and all 2 were appropriately concluded as negative. Overall there is no convincing evidence that soluble cobalt salts (tested as chloride and sulfate) are mutagenic in the bacterial reverse mutations test systems.

Conclusion:

Soluble cobalt salts do not elicit any mutagenic activity either in bacterial or mammalian test systems. However they induce some genotoxic effects in vitro, mainly manifest as DNA strand or chromosome breaks, which are consistent with a reactive oxygen mechanism, as has been proposed by various authors. A weight-of-evidence approach was applied, considering positive as well as negative in vivo clastogenicity studies and the absence of such chromosome damage in humans that are occupationally exposed to inorganic cobalt substances. It was concluded that effective protective processes exist in vivo to prevent genetic toxicity with relevance for humans from the soluble cobalt salts category.

Reference: * SIAR, 2014: https://hpvchemicals.oecd.org/ui/handler.axd?id=b789fd1c-bab3-433c-9f47-3cbd49042976

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Justification for classification or non-classification

There is no convincing evidence that soluble cobalt salts (tested as chloride and sulfate) are mutagenic in the bacterial reverse mutations test systems (SIAR, 2014).