Hexadecyl (R)-12-hydroxyoleate

Endpoint summary

Additional information

The experimental dataset for Annex VIII is not complete. In order to fulfil the standard information requirements, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across from structurally related substances was conducted.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular for aquatic toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 whereby substances may be predicted as similar provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity.

The target substance hexadecyl (R)-12-hydroxyoleate is mainly specified as an ester of a linear C16 alcohol and a C18:1(OH) fatty acid. The read-across substances dodecyl oleate (CAS 36078-10-1) and 9-octadecenoic acid (Z)-, 9-octadecenyl ester, (Z)- (CAS 3687-45-4) are representative to evaluate the aquatic toxicity of the target substance hexadecyl (R)-12-hydroxyoleate. Both read-across substances are characterized by the same fatty acid component (C18 unsatd.) esterified with C12- and C18 unsatd.-alcohol components, respectively. A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

All available experimental studies for the source substances were performed according to internationally accepted guidelines. No toxicity was observed up to the limit of water solubility in all available experimental studies. The water solubility of the target substance was determined to be < 0.7 mg/L at 24 °C, pH = 7 (referring to the ester components).

The long-term toxicity to aquatic invertebrates was tested in a standard OECD guideline study according to OECD 211 using suitable source substances (CAS 36078-10-1 and CAS 3687-45-4). No inhibition of reproduction was observed after 21 d resulting in a NOELR/NOEC ≥ 100 mg/L (i.e. above the water solubility limit). Investigation of the short-term toxicity to aquatic invertebrates was not deemed necessary since a chronic study is available.
The same was recorded for aquatic algae. No inhibition of growth was recorded resulting in an ErL50 (72 h) > 100 mg/L and NOELR (72 h) ≥ 100 mg/L. Moreover, no mortality of freshwater fish was recorded after 96 h resulting in a LL50 > 100 mg/L.

It is not anticipated that the biodegradation process in sewage treatment plants might be inhibited. No inhibition of the respiration rate of activated sludge microorganisms was recorded in a guideline study according to OECD 209.

Based on the result from available studies from structurally related source substances (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) it can be concluded that the target substance hexadecyl (R)-12-hydroxyoleate (CAS 10401-55-5) has no toxic effects on freshwater organisms up to the limit of the water solubility. The data matrix of the analogue justification in IUCLID Section 13 shows that all reliable data from the source substances support the read-across by a consistent pattern of results.