Hydrocarbons, C16-C22, n-alkanes, isoalkanes, <2% aromatics

Endpoint summary

Additional information

No in vitro or in vivo mutagenicity studies are available for the registration substance itself. However, reliable data are available for a number of other Fischer-Tropsch process-derived substances covering the entire carbon number range relevant for Hydrocarbons, C16-C22, n-alkanes, isoalkanes, <2% aromatics. These are used as weight of evidence.

 

Data are available for Hydrocarbons, C18-C24, isoalkanes, <2% aromatics (GTL Solvent GS310) and Hydrocarbons, C15 -C19, n-alkanes, isoalkanes, <2% aromatics (GTL Solvent GS270) from bacterial mutagenicity studies and an in vitro cytogenicity study. Supporting studies are also available for GTL Gasoil (C8-C26) and GTL Base Oil Distillates (C18-C50), including in vitro and in vivo micronucleus tests. There are no mammalian mutagenicity toxicity studies for Hydrocarbons, C16-C22, n-alkanes, isoalkanes, <2% aromatics. 

A bacterial mutagenicity test was performed with Hydrocarbons, C18-C24, isoalkanes, <2% aromatics according to OECD 471 and GLP (Westerink, 2014e). Strains tested were Salmonella typhimurium strains TA 98, TA 100, TA 1535 and TA 1537, and Escherichia coli strain WP2 uvrA, both with and without metabolic activation (Aroclor 1254-induced rat liver S9). The test was negative both with and without metabolic activation.

An in vitro chromosome aberration study was performed for Hydrocarbons, C18-C24, isoalkanes, <2% aromatics according to OECD 473 and GLP (Sokolowski, 2015). In the absence and presence of metabolic activation, no clear cytotoxicity was observed up to the highest applied concentration, (2960.0 μg/ml). In the presence of metabolic activation no relevant increase in chromosomal aberrations was observed. In Experiment I in the absence of metabolic activation, one single increase in chromosomal aberrations, above the laboratory historical control data range (0.0 – 3.0 % aberrant cells, excluding gaps), was observed after treatment with 1691.4 μg/ml (4.5 % aberrant cells, excluding gaps). The value is not statistically significant and no dose-dependency was observed. In Experiment IIA in the absence of metabolic activation after treatment with 1691.4 μg/ml one single statistically significant increase in chromosomal aberrations (3.8 % aberrant cells, excluding gaps), above the laboratory historical control data range (0.0 – 2.5 % aberrant cells, excluding gaps), was observed. No dose-dependency was observed in this experimental part. In Experiment IIB in the absence of S9 mix this finding could not be confirmed. No evidence of an increase in polyploid metaphases was noticed after treatment. Appropriate mutagens were used as positive controls. They induced statistically significant increases in the number of cells with structural chromosome aberrations. It was concluded that the test substance was negative for cytogenicity up to limit concentrations under the conditions of the test.

Hydrocarbons, C15-C19, n-alkanes, isoalkanes, <2% aromatics has been tested for mutagenicity to bacteria in a study conducted according to OECD TG 471 and in compliance with GLP (Westerink, 2014f). No evidence of substance induced increase in the frequency of revertants was noted in the presence or absence of metabolic activation in Salmonella typhimurium strains TA1535, TA1537, TA98 and Escherichia coli WP2 uvrA when tested up to limit concentrations. Similar results were obtained in two independent experiments using plate incorporation. Appropriate solvent and positive controls were included and gave expected results. It is concluded that the test substance is negative for mutagenicity to bacteria under the conditions of the test.

Hydrocarbons, C15-C19, n-alkanes, isoalkanes, <2% aromaticshas been tested for potential for cytogenicity in a chromosome aberration study conducted according to OECD TG 473 and in compliance with GLP in two independent experiments (Bohnenberger, 2014). No biologically relevant evidence of a test substance induced increase in the number of cells with aberrations was observed when tested in peripheral human lymphocytes in the presence or absence of metabolic activation up to cytotoxic or limit concentrations. A single statistically significant increase in the number of cells with aberrations was observed in the first experiment, which was within the range of historical controls so not considered biologically relevant. An increase above the level of historical controls was observed at one concentration in experiment 2, but this was neither statistically significant nor dose-dependent so not considered biologically relevant. Appropriate solvent and positive controls were included and gave expected results. It is concluded that the test substance is negative for clastogenicity under the conditions of the test.

 

An Ames test was performed for GTL Gasoil according to Annex V guidelines and GLP (Bowles, 2006a). Strains tested were Salmonella typhimurim strains TA 98, TA 100, TA 1535 and TA 1537, and Escherichia coli strain WP2uvrA, both with and without metabolic activation (rat liver S9). A micronucleus test in human lymphocytes in vitro was carried out according to the draft OECD Test Guideline 487. The test results show that GTL Gasoil is not clastogenic or aneugenic (Durward, 2006a).

GTL Base Oil Distillates has been tested in a bacterial mutagenicity study according to OECD 471 and under GLP using Salmonella typhimurium strains TA 98, TA 100, TA 1535, TA 1537 and Escherichia coli WP2uvrA (Bowles, 2006b). The test material was dissolved in tetrahydrofuran at concentrations up to 5000 µg/plate. Appropriate solvent and positive controls were included and gave expected results. No toxicity to bacterial cells was observed. No significant increase in the number of revertants was observed at any concentration with and without metabolic activation in any of the strains tested. The results were confirmed in a repeat experiment; both experiments used the direct plate incorporation method.

An in vitro micronucleus study has been conducted using GTL Base Oil Distillates following OECD draft guideline 487 and conducted under GLP conditions (Durward, 2006b). No increase in the incidence of micronuclei was observed in duplicate cultures of human lymphocytes at any concentration in either the initial experiment (4 hour exposure, 16 hour expression, with and without metabolic activation) or the repeat experiment (20 hour exposure without metabolic activation; 4 hour exposure, 16 hour expression, with metabolic activation). No test material induced toxicity was observed. The test material was dissolved in acetone, and the maximum concentration tested was 2500 µg/plate; higher concentrations could not be tested due to difficulties in formulating the test material in the vehicle. The vehicle controls had frequencies of cells with micronuclei within the range expected for normal human lymphocytes, and appropriate positive controls were concluded and induced significant increases in the number of cells with micronuclei. It was concluded that the test material is non-clastogenic and non-aneugenic to human lymphocytes in vitro.

An in vitro chromosome aberration test in human lymphocytes with GTL Gasoil, carried out in accordance with OECD 473 was negative both with and without metabolic activation (Lacey, 2010). The test substances was therefore considered to be non-clastogenic to human lymphocytes in vitro.

An in vivo chromosome aberration study was carried out on GTL Gasoil according to OECD 475 and under GLP (Morris, 2011a). Male Wistar rats were dosed orally at 0,0.5, 1.0 and 5.0 g/kg bwin arachis oil. No increase in the incidence of cells with chromosome aberrations excluding gaps or of polyploid cells was observed in bone marrow up to the highest dose tested. No premature deaths or clinical signs were observed at any dose level. The positive control item produced a marked increase in the frequency of chromosome aberration.

An in vitro micronucleus study has been conducted using GTL Base Oil Distillates following OECD draft guideline 487 and conducted under GLP conditions (Durward, 2006b). No increase in the incidence of micronuclei was observed in duplicate cultures of human lymphocytes at any concentration in either the initial experiment (4 hour exposure, 16 hour expression, with and without metabolic activation) or the repeat experiment (20 hour exposure without metabolic activation; 4 hour exposure, 16 hour expression, with metabolic activation). No test material induced toxicity was observed. The test material was dissolved in acetone, and the maximum concentration tested was 2500 µg/plate; higher concentrations could not be tested due to difficulties in formulating the test material in the vehicle. The vehicle controls had frequencies of cells with micronuclei within the range expected for normal human lymphocytes, and appropriate positive controls were concluded and induced significant increases in the number of cells with micronuclei. It was concluded that the test material is non-clastogenic and non-aneugenic to human lymphocytes in vitro.

Further evidence of the lack of effects on chromosomes in vitro was obtained when GTL Base Oil Distillates was tested according to OECD 473 and under GLP (Morris, 2010). No statistically significant increase in the frequency of cells with chromosome aberrations was observed in either the initial or the repeat experiment when tested with and without metabolic activation up to a dose level that was limited by the onset of precipitate. Appropriate solvent and positive controls were included and gave expected results.

Evidence from the in vitro studies is supported by data from an in vivo chromosome aberration study on GTL Base Oil Distillates, conducted according to OECD 475 and under GLP (Morris, 2011b). Male Wistar rats were dosed orally at 0,500, 1000 and 2000 mg/kg bwin arachis oil. No increase in the incidence of cells with chromosome aberrations excluding gaps or of polyploid cells was observed in bone marrow up to the highest dose tested. No premature deaths or clinical signs were observed at any dose level. The positive control item produced a marked increase in the frequency of chromosome aberration.

Based on the weight of evidence from the available studies on the registered and the related substances it can be concluded that Hydrocarbons, C16-C22, n-alkanes, isoalkanes, <2% aromatics is not genotoxic.

Short description of key information:
In vitro:
Gene mutation (Bacterial reverse mutation assay / Ames test): negative with and without activation in Salmonella typhimurium strains (TA 98, 100, 1535, 1537) and Escherichia coli WP2uvrA (OECD 471).
Cytogenicity in mammalian cells: negative with and without activation in human lymphocytes (OECD Draft Guideline 487). Negative with and without activation in human lymphocytes (OECD 473).

In vivo:
Cytogenicity: negative in Mammalian Bone Marrow Chromosome Aberration Test (OECD 474/EU B.11)

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based on the available read-across in vitro and in vivo data for the registered substance and relevant read-across substances, Hydrocarbons, C16-C22, n-alkanes, isoalkanes, <2% aromatics is not genotoxic and does not require classification according to Regulation (EC) No. 1272/2008.