Sulfuric acid, C12-14 (even numbered)-alkyl esters, (2-hydroxylpropyl)ammonium salts

Carcinogenicity

Description of key information

OECD 453, rat, combined chronic toxicity/carcinogenicity, oral: not carcinogenic
NOAEL = 1125 mg/kg bw/day; LOAEL > 1125 mg/kg bw/day

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 125 mg/kg bw/day

Study duration:

chronic

Species:

rat

Carcinogenicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Carcinogenicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

The available data on carcinogenicity do not meet the criteria for classification according to Regulation (EC) 1272/2008, and are therefore conclusive but not sufficient for classification.

Additional information

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. This structural feature confers the surfactant properties of the alkyl sulfates. The surfactant property of the members of the AS category in turn represent the predominant attribute in mediating effects on mammalian health. Therefore, the AS of the AS category have similar physicochemical, 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 program carrying out Human and Environmental Risk Assessments (HERA [2]), further supporting the read-across approach between structurally related AS.

A detailed justification for grouping of alkyl sulfates into a category is provided separately. Please refer for more details on the read-across also to the document “AS Category Approach Justification” attached in Section 13 of IUCLID.

A reliable combined chronic toxicity/carcinogenicity study (Unilever, 1995a&B) was conducted with C12-15 AS Na (CAS 68890-70-0). For two combined chronic toxicity/carcinogenicity studies similar to OECD Guideline 453 C12-15 AS Na (CAS 68890-70-0) was prepared by two different production methods (high conversion bleached or HCB; and low conversion, unbleached or LCU). The substances of these different production methods differed slightly in chain length distribution, the latter having a slightly higher proportion of the C15AS Na. In both studies, the test material was dosed at 0, 0.015, 0.15 and 1.5% in the diet. There was no increase in tumor incidence, nor any impact on tumor type in either study. For both studies, approximately 70% of animals survived to study termination. Mortality was similar across dosage groups and controls. Animals in the 1.5% dose groups in both studies exhibited reduced food and water consumption, and slower growth rates. Within these high dose groups, there were a decreased number of total tumors and tumor-bearing animals.

Other pathological findings are summarized in the Section Repeated dose toxicity. Increased absolute liver weights and liver to body weight ratios, hypertrophy of the hepatic parenchyma, increased relative testicular weights, reduced incidence and severity of chronic nephropathy and nephrocalcinosis, and reduced arterial medial hypertrophy were among the findings at the higher dose levels.

Alkyl sulfates (AS) show a consistent absence of mutagenic activity when tested in in-vitro and in-vivo tests. Neither AS nor its metabolites possess electrophilic functional groups or functional groups associated with mutagenic activity. Taken together with the results of the carcinogenicity studies, AS are considered as non-carcinogenic.

 

Influence of counter-ions on carcinogenicity

The effects on health of isopropanolamine (MIPA) are dominated by its corrosive properties. MIPA is listed in Annex VI of EG 1272/2008 as Skin Corrosive Category 1B, H314. Further information indicates MIPA to be moderately toxic after dermal application. During the registration process for 2010 MIPA was also classified as harmful in contact with skin (Acute Toxicity Cat 4, H312 according to Regulation 1272/2008/EC). There is no indication of genotoxic or carcinogenic effects of MIPA. Therefore, MIPA is not expected to be carcinogenic and therefore will not confer carcinogenicity to alkyl ether sulfates.

 

[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