Perchloric acid

Endpoint summary

Additional information

Genotoxicity in vitro

Only an Ames test is available with perchloric acid. However, once absorbed in the general circulation, perchloric acid is expected to be transformed into perchlorate moiety because of the blood buffering effect. As sodium ion by itself is not expected to induce genotoxicity, for chromosome aberration and mammalian gene mutation evaluation the results of studies on sodium perchlorate are used in a read across approach to evaluate perchloric acid genotoxicity.

Ames test

In a study (CIT, 2003), the potential of Perchloric acid to induce reverse mutation in Salmonella typhimurium was evaluated according to OECD 471 guideline.

The test item was tested in a preliminary test and two mutagenicity experiments. The preliminary test, both experiments without S9 mix and the first experiment with S9 mix were performed according to the direct plate incorporation method. The second experiment with S9 mix was performed according to the preincubation method.

The selected treatment-levels were: 312.5, 625, 1250, 2500 and 5000 μg/plate, for both mutagenicity experiments with and without S9 mix.

No precipitate was observed in the Petri plates when scoring the revertants at all dose-levels.

With the direct plate incorporation method, no toxicity was noted towards all the strains used, both with and without S9 mix.

With the preincubation method, a moderate to marked toxicity was observed at dose-levels ≥ 2500 μg/plate in all the strains used.

The test item did not induce any noteworthy increase in the number of revertants, both with and without S9 mix, in any of the five strains.

The number of revertants for the vehicle and positive controls was as specified in the acceptance criteria. The study was therefore considered valid.

In this study, the test item Perchloric acid did not show mutagenic activity in the bacterial reverse mutation test with Salmonella typhimurium.

Chromosome aberration (Read-accross was done with sodium perchlorate)

A study was conducted at CIT Laboratories France to evaluate the potential of the test item Anhydrous Sodium Perchlorate to induce chromosome aberrations in cultured human lymphocytes. The study was performed according to international guidelines and in compliance with the principles of GLP. The test item was tested in two independent experiments, both with and without a liver metabolizing system (S9 mix), obtained from rats previously treated with Aroclor 1254. Under the experimental conditions, anhydrous sodium perchlorate did not induce chromosome aberrations in cultured human lymphocytes.

Mammalian gene mutation (Read-accross was done with sodium perchlorate)

A study was performed at CIT Laboratories France to investigate the potential of Anhydrous Sodium Perchlorate to induce mutations at the TK (thymidine kinase) locus in L5178Y mouse lymphoma cells. The study was performed according to the international guidelines (OECD 476 and Commission Directive No. B17) and in compliance with the Principles of Good Laboratory Practice Regulations. After a preliminary toxicity test, Anhydrous Sodium Perchlorate was tested in two independent experiments, in the absence and presence of a rat liver metabolising system (S9 mix). Cytotoxicity was measured by assessment of adjusted relative total growth (Adj. RTG) and relative suspension growth (Adj. RSG) as well as cloning efficiency following the expression time (CE2). The numbers of mutant clones (differentiating small and large colonies) were checked after the expression of the mutant phenotype. Using a treatment volume of 100 μL/20 mL, the selected dose-levels were 156.3, 312.5, 625, 1250, 2500 and 5000 μg/mL for both mutagenicity experiments with and without the S9 mix. Following the 3-hour treatment and the 24-hour treatment without S9 mix, no noteworthy cytotoxicity was found. Similarly there was no evidence of mutagenicity, either following either the 3-hour or the 24-hour treatment. Experiments with the S9 mix revealed no noteworthy cytotoxicity in the first experiment but the second experiment showed evidence of slight toxicity at the highest dose level (5000 µg/mL), shown by a 39% decrease in Adj. RTG. However, there was no significant mutation frequency noted following the 3-hour treatment in either experiment. Under the experimental conditions, the test item did not show any mutagenic activity in the mouse lymphoma assay.

Genotoxicity in vivo

As all the in vitro tests gave negative results, an in vivo study is not required.

Justification for selection of genetic toxicity endpoint
Rationale based on the 3 available studies on Ames test, chromosome aberration test and Mammalian gene mutation test

Short description of key information:
The 3 studies gave negative results.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the results on the available studies which gave negative results in the three different in vitro studies (Ames test, chromosome aberration and mouse lymphoma assay), no classification is required for genotoxicity, according to the DSD 67548/EC and the regulation CLP 1272/2008 criteria.