Hexachloroiridic acid

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Hexachloroiridic acid produced a weak positive response when tested in a rec assay with Bacillus subtilis, indicative of possible DNA damage (Kada et al., 1980; Kanematsu et al., 1980; Leifer et al., 1981 ). In a subsequent spot test using 2 strains of Escherichia coli (B/r WP2 try- and WP2 hcr- try-) and 5 strains of Salmonella typhimurium (TA98, TA100, TA1535, TA1537, TA1538), it failed to induce reversions indicative of mutation (Kanematsu et al., 1980).

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

not stated

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: Not to current international guidleines, with significant deviations from the protocol. For example no revertant data provided, no metabolic activation, and no controls used.

Qualifier:

no guideline followed

Principles of method if other than guideline:

The spot test, first described by Iyer and Sybalsky (1958) and later by Ames et al. (1975).

GLP compliance:

not specified

Type of assay:

other: Spot test

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Species / strain / cell type:

S. typhimurium TA 1538

Species / strain / cell type:

E. coli, other: B/r WP2 try- and WP2 hcr- try-

Metabolic activation:

without

Test concentrations with justification for top dose:

0.001-10 M

Details on test system and experimental conditions:

Bacterial strains were spread on plates containing broth-enriched agar. Filter-paper disks containing the test substance were placed onto the plates. Revertant colonies around the disk were counted. Reversion assays with the test substance in liquid were also carried out with the two E.coli strains.

Species / strain:

other: all strains

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative without metabolic activation

In a limited assay (Spot test), hexachloroiridic acid failed to induce reverse mutations in bacteria.

Executive summary:

In a limited assay (the spot test), filter paper discs containing hexachloroiridic acid were place onto agar plates containing bacterial strains Salmonella typhimurium TA98, TA100, TA1535, TA1537, TA1538 or Escherichia coli strains B/r WP2 try- and WP2 hcr- try-. Revertant colonies around the discs were counted. Reversion assays with the test substance in liquid were also carried out with the two E.coli strains.

The test substance (at up to 10 M) failed to induce reverse mutations in bacteria.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

The genotoxicity data available on hexachloroiridic acid are limited.

 

In a non-guideline study - a rec assay for differential killing (as an indicator of DNA damage) using Basillus subtilis - gave a result which the investigators described as indicative of a mild positive rec effect (Kanematsu et al., 1980). [Likely the same study reported in Kada et al. (1980) and Leifer et al. (1981).]

 

In a limited bacterial mutation assay (the spot test), filter paper discs containing hexachloroiridic acid were place onto agar plates containing Salmonella typhimurium TA98, TA100, TA1535, TA1537 and TA1538 or Escherichia coli strains B/r WP2 try- and WP2 hcr- try-. Revertant colonies around the discs were counted. Reversion assays with the test substance in liquid were also carried out with the two E.coli strains. The test substance (at up to 10 M) failed to induce reverse mutations in bacteria (Kanematsu et al., 1980).

 

 

 

References not included elsewhere in IUCLID

Kada T, Hirano K and Shirasu Y (1980). Screening of environmental chemical mutagens by the rec-assay system with Bacillus subtilis. Chemical Mutagens - Principles and Methods for their Detection 6, 149-173.

 

Leifer Z, Kada T, Mandel M, Zeiger E, Stafford R and Rosenkranz HS (1981). Evaluation of tests using DNA repair-deficient bacteria for predicting genotoxicity and carcinogenicity: report of the U.S. EPA's Gene-Tox program. Mutation Research 211-297.

Justification for selection of genetic toxicity endpoint
No single, good-quality guideline study available. Limited in vitro data are available ("spot test" with Salmonella typhimurium and Escherichia coli; and rec assay with Bacillus subtilis).

Justification for classification or non-classification

Data are insufficient on which to confidently base classification. Classification, according to EU CLP critiera (1272/2008), for germ cell mutagenicity generally requires positive results from appropriate in vivo studies. As such, no classification is considered neccesary.