Registration Dossier

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information
In vitro micronucleus assay (OECD487) using human lymphocytes. AMES reverse mutattion assay (OECD471) in bacterial cells.
Endpoint conclusion
Endpoint conclusion:
adverse effect observed (positive)

Additional information

Additional information from genetic toxicity in vitro:

Potassium dicyanoaurate was tested for its ability to induce reverse mutations in a screening and definitive Ames assay (McGarry 2013, McGarry 2014) in five strains of Salmonella typhimurium (TA98, TA100, TA102, TA1535 and TA1537), following OECD guideline 471. Two experiments were carried out with 7 test concentrations. There was no mutation induced at concentrations up to toxic concentrations in the presence and absence of rat liver S9 metabolic activation. Cytotoxicity was observed in various strains at various concentrations with and without metabolic activation.

In an in vitro experiment for chromosomal damage, human lymphocytes were exposed to 8 concentrations of potassium dicyanoaurate with and without activation for 4 and 24 hours (Bowles 2015). Potassium dicyanoaurate was determined to be mutagenic to human lymphocytes under the conditions of this test.

Overall, there is no consistent evidence of genotoxicity below the cytotoxic concentration for potassium dicyanoaurate.

Justification for selection of genetic toxicity endpoint
The current key study (OECD487) represents the most relevant genetic toxicity assay using mammalian cells and was a guideline study conducted in accordance with GLP. However, this study produced a positive result indicating a potential for the test substance to cause cromosome damage. Therefore, a testing proposal for the conduct of an in vivo micronucleus assay has been made in accordance with Annex VIII Section 8.4 Column 2 rules.

Justification for classification or non-classification

There is insufficient information to conclude the genotoxicity potential of potassium dicyanoaurate, as conflicting results were observed in two in vitro studies. In consequence, no classification is required until further data are available.