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Key value for chemical safety assessment

Additional information

In vitro data for trifluoro(tetrahydrofuran)boran are not available.

Two Ames tests are available for boron trifluoride dihydrate and for tetrahydrofuran.

In the Ames test performed by Huntigdon Life Sciences (2010), no evidence of mutagenic activity was seen at any concentration of boron trifluoride dihydrate in either mutation test with or without S9 -mix (concentrations up to 5000 µg/plate were tested, vehicle: water). Another Ames test published by NTP in 1998 reported no mutagenicity in the testing strains S. typhimurium TA 1535, TA 1537, TA 98 and TA 100 after treatment with tetrahydrofuran up to concentrations of up to 10000 ug/plate with and without S9 -mix.

Boron trifluoride dihydrate (CAS: 13319-75-0) was tested for mutagenic potential in an in vitro mammalian cell mutation assay (Huntingdon Life Sciences, 2010). The study consisted of a preliminary toxicity test and two main tests comprising three independent mutagenicity assays. The cells were exposed for either 3 hours or 24 hours in the absence of exogenous metabolic activation (S9 mix) or 3 hours in the presence of S9 mix. Boron trifluoride dihydrate was found to be soluble at 67.8 mg/mL in water. A final concentration of 450 mg/mL, dosed at 1%v/v, was used as the maximum concentration in the preliminary toxicity test, in order to test up to the highest concentration that does not cause a fluctuation in pH of more than 1.0 unit. Toxicity was observed in the preliminary toxicity test. Following a 3 hour exposure to boron trifluoride dihydrate at concentrations from 0.9 to 450 mg/mL, relative suspension growth (RSG) was reduced from 107 to 71% and from 113 to 68% in the absence and presence of S9 mix respectively. Following a 24-hour exposure in the absence of S9 mix RSG was reduced from 114 to 1%. The concentrations assessed for determination of mutant frequency in the main test were based upon these data, the objective being to assess concentrations which span the complete toxicity range of approximately 10 to 100% relative total growth (RTG), or to assess exposure up to the highest concentration that does not cause a fluctuation in pH of more than 1.0 unit. Following 3-hour treatment in the absence and presence of S9 mix, there were no clear increases in the mean mutant frequencies of any of the test concentrations assessed that exceeded the sum of the mean concurrent vehicle control mutant frequency and the Global Evaluation Factor (GEF), within acceptable levels of toxicity. The maximum concentrations assessed for mutant frequency in the 3 hour treatment in the absence and presence of S9 mix was 450 mg/mL. In the absence and presence of S9 mix RTG was reduced to 51 and 46% respectively. In the 24-hour treatment, the maximum concentration assessed for mutant frequency was 300 mg/mL. No increase in mutant frequency exceeded the sum of the mean concurrent vehicle control mutant frequency and the GEF was observed at concentrations up to 300 mg/mL, where RTG was reduced to 11%. In all tests the concurrent vehicle and positive control were within acceptable ranges. It was concluded that boron trifluoride dihydrate did not demonstrate mutagenic potential in this in vitro cell mutation assay, under the experimental conditions described.

A study was performed to assess the ability of boron trifluoride dihydrate (CAS: 13329-75-0) to induce chromosomal aberrations in human lymphocytes cultured in vitro (Huntingdon Life Sciences, 2010). Human lymphocytes were exposed to the test substance both in the absence and presence of S9 mix. In the absence of S9 mix, boron trifluoride dihydrate caused statistically significant increases in the proportion of metaphase figures containing chromosomal aberrations at 450 µg/mL (3 hour treatment, including gaps; no significant increase if excluding gaps) and at 162 µg/mL (21 hour treatment, including gaps) and 270 µg/mL (21 hour treatment, excluding and including gaps), when compared with the concurrent solvent control. In the presence of S9 mix, boron trifluoride dihydrate caused no statistically significant increases in the proportion of metaphase figures containing chromosomal aberrations, at any concentration, when compared with the solvent control, in either test. No statistically significant increases in the proportion of polyploid cells were observed during metaphase analysis, in either test. Boron trifluoride dihydrate has shown evidence of causing an increase in the frequency of structural chromosome aberrations, in the absence of S9 mix after 21-hour exposure period, in this in vitro cytogenetic test system, under the experimental conditions described.

In vivo data for trifluoro(tetrahydrofuran)boron are not available.

NTP (1998) reported an in vivo micronucleus test with tetrahydrofuran (CAS: 109-99-9). Male and female B6C3F1 mice were offered the test substance via the inhalation route (vapour) in concentrations of 66, 200, 600, 1800 or 2500 ppm for 6 h/d and 5 d/w. The frequencies of micronucleated erythorcytes were determined in peripheral blood samples obtained from male and female mice dosed by inhalation at 0 (chamber control), 600, 1800 or 5000 ppm in this 14 -week inhalation toxicity studies. With the exception of an equivocal response in male mice represented as an increased frequency of micronucleated normochromatic cells (P = 0.074), tetrahydrofuran failed to produce a positive response in female mice based on micronucleated polychromatic or normochromatic erythrocytes or a positive response in male mice based on micronucleated polychromatic erythrocytes.

Boron trifluoride as the leading toxophor is expected to induce severe toxicity after exposure well before effects on mutagenicity are induced (for further details see attachement). For this reason, further in vivo mutagenicity studies are scientifically unjustified.


Endpoint Conclusion:

Justification for classification or non-classification

No data are available for the test compound. Based on the available data received from boron trifluoride and tetrahydrofuran, no classification is proposed.