Sodium 2-butyloctyl sulphate

Endpoint summary

Additional information

No data on genetic toxicity are available for C12AS branched Na (CAS 94200-74-5). Therefore this endpoint is covered by read across to structurally related alkyl sulfates (AS) for weight-of-evidence approach, i.e. C12AS Na (CAS 151-21-3). The possibility of a read-across to other alkyl sulfates in accordance with Regulation (EC) No 1907/2006 Annex XI 1.5. Grouping of substances and read-across approach was assessed. In Annex XI 1.5 it is given that a read-across approach is possible for substances, whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity. The AS reported within the AS category show structural similarity. The most important common structural feature of the category members is the presence of a predominantly linear aliphatic hydrocarbon chain with a polar sulfate group, neutralized with a counter ion. The AS of the AS category also have similar physico-chemical, environmental and toxicological properties, validating the read across approach within the category. The approach of grouping different AS for the evaluation of their effects on human health and the environment was also made by the OECD in the SIDS initial assessment profile [1] and by a voluntary industry programme carrying out Human and Environmental Risk Assessments (HERA [2]), further supporting the read across approach between structurally related AS.

There are three key studies available addressing genetic toxicity for the read-across substance C12AS Na (CAS 151-21-3).

Mutagenicity in bacteria was assessed in a study performed according to OECD Guideline 471. Tester strain TA 102 or E.coli were not used during the conduct of the study (Banduhn, 1988). In the study with C12AS Na (CAS 151-21-3) Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 1538 and TA 100 were treated using the plate incorporation method with and without the addition of a rat liver S9-mix. The dose range was 8, 40, 200, 1000, 5000 µg/plate for the first experiment (with and without S9 mix) as well as 5, 10, 20, 40, 80 µg/plate (-S9 mix) and 2.5, 10, 40, 160, 640 µg/plate (+S9 mix) for the second experiment. Results achieved with vehicle (water) and positive controls were valid. Cytotoxicity was observed in presence and absence of metabolic activation occasionally at around 200 µg/plate while no genotoxicity was observed for C12AS Na (CAS 151-21-3) at all.

The mutagenicity of C12AS Na (CAS 151-21-3) in a mammalian cell line was investigated similar to OECD guideline 476 using the mouse lymphoma L5178Y cells with and without metabolic activation (McGregor, 1988). The test concentrations were 3.125, 6.25, 10, 12.5, 20, 25, 30, 40, 50, 55, 60, 65, 70, 80 and 100 µg/mL without and 50, 55, 60, 65, 70, 75, 80, 85, 90 and 95 µg/mL with metabolic activation. Results achieved with the negative (untreated), vehicle (DMSO) and positive controls were valid. Cytotoxicity was observed in presence and absence of metabolic activation while no genotoxicity was observed under both circumstances for C12AS Na (CAS 151-21-3).

The potential of C12AS Na (CAS 151-21-3) to induce in vivo chromosomal aberration was assessed in a study comparable to the dominant lethal test with CD-1 mouse (Unilever, 1976). The test substance was administered via gavage at doses of 120, 380 and 1200 mg/kg bw to a total of 225 males. Each male was caged with 2 virgin females for 7 days. Thereafter males were caged with another two virgin females for 7 days. This was repeated another 6 times. The males were not further examined. Females were sacrificed 13 days after the assumed date of fertilization, i.e.15 or 16 days after caging females with male and the frequency of early death, frequency of pregnancy and number of implantations was assessed. No adverse effects on the frequency of early death, frequency of pregnancy and number of implantations occurred. Thus the test substance did not show clastogenicity at doses of 120, 380 and 1200.

In conclusion, the substance did not show any genotoxic potential. This is supported by the conclusions of the HERA Draft report “AS are not genotoxic, mutagenic or carcinogenic…” and the conclusions of the SIDS initial assessment profile “Alkyl sulfates of different chain length and with different counter ions were not mutagenic in standard bacterial and mammalian cell systems [...]. There was also no indication for a genotoxic potential of alkyl sulfates in various in vivo studies on mice […].”

 

[1] SIDS initial assessment profile, (2007);
http://www.aciscience.org/docs/Alkyl_Sulfates_Final_SIAP.pdf

[2] (HERA Draft report, 2002);
http://www.heraproject.com/files/3-HH-04-%20HERA%20AS%20HH%20web%20wd.pdf

Justification for selection of genetic toxicity endpoint
No study selected as all three studies were negative.

Short description of key information:
In vitro gene mutation:
Bacterial reverse mutation assay (Ames test / OECD guideline 471): negative
In vitro mammalian cell gene muatation assay (MLA / OECD guideline 476): negative
In vivo clastogenicity:
In vivo study comparable to the dominant lethal test (DLA / OECD guideline 478): negative

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

The available data on genetic toxicity do not meet the criteria for classification according to Regulation (EC) 1272/2008 or Directive 67/548/EEC, and are therefore conclusive but not sufficient for classification.