Triphenyl phosphate

Endpoint summary

Additional information

Triphenyl phosphate was investigated using the Salmonella/microsome plate incorporation test for point mutagenic effects in doses of up to and including 5000 µg per plate on the Salmonella typhimurium strains TA 1535, TA 100, TA 1537, TA 98 and TA 102. Doses up to and including 5000 µg per plate did not cause any bacteriotoxic effects. Total bacteria counts remained unchanged and no inhibition of growth was observed. Substance precipitation occurred at the dose of 5000 µg per plate. Evidence of mutagenic activity was not seen. No biologically relevant increase in the mutant count, in comparison to the negative controls, was observed in any of the strains tested, without and with S9 mix, in the plate incorporation as well as in the preincubation modification, under the experimental conditions applied. Therefore, triphenyl phosphate is considered to be non-mutagenic in the Salmonella/microsome test.

This result is confirmed by other investigators using bacterial gene mutation tests on S.typhimurium strains and the yeast S.cerevisiae D4 with and without metabolic activation.

The clastogenic potential of triphenyl phosphate was evaluated in a chromosome aberration test in vitro according to OECD TG 473. Chinese hamster V79 cells were exposed for 4 hours to the test item (dissolved in DMSO) in the presence and absence of S9 mix. The cells were harvested 18 and 30 hours after start of treatment. An additional experiment was performed using continuous treatment for 18 hours and harvest at the same time. Concentrations chosen for reading of metaphases based on cytotoxicity results were in the range of 3.5 to 40 µg/ml. None of the cultures treated with triphenyl phosphate in the presence and absence of S9 mix exhibited biologically relevant or statistically increased numbers of aberrant metaphases. Based on this study, triphenyl phosphate is considered not to be clastogenic in mammalian cells in vitro.

Triphenyl phosphate was tested in the in vitro mammalian cell gene mutation test on mouse lymphoma cells with and without metabolic activation according to OECD TG 476. Concentrations of 3.13 to 75 µg/ml were tested. The test item was dissolved in DMSO. Cytotoxicity occured in the highest concentrations tested in the cultures with and without S9 mix. All mutation frequencies were within the expected range of spontaneous background and the results are considered negative. Thus, triphenyl phosphate was shown to be not mutagenic in the mouse lymphoma assay.

Unscheduled DNA synthesis was examined in Syrian hamster fibroblast cells at concentrations of 0.05 to 10 x 10 -5 M. After 5 hours of incubation without metabolic activation in the presence of 3H-thymidine. TPP showed no genotoxic effect (Schmuck, 1989).

Justification for selection of genetic toxicity endpoint
no selection was made since the assessment is based on several reliable genotoxicity studies

Short description of key information:
Tests for gene mutations in bacteria as well as yeast and mammalian cells did not reveal any sign of mutagenicity. In an vitro chromosome aberration test using Chinese hamster V79 cells TPP did not show any signs of clastogenicity. A UDS test system in Syrian hamster fibroblast cells showed no genotoxic effects.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Triphenyl phosphate was shown to be not mutagenic/genotoxic in several in vitro tests. According to EU Regulation 1272/2008 no classification for mutagenicity is warranted.