1,2,3-propanetriyl triisooctadecanoate

Endpoint summary

Additional information

Data investigating the terrestrial toxicity of 1,2,3-propanetriyl triisooctadecanoate (CAS 26942-95-0) are not available.

In accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across from a structurally related substance was conducted to fulfil the standard information requirements. 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). According to Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 substances can be considered to be similar if 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 1,2,3-propanetriyl triisooctadecanoate (CAS 26942-95-0) is characterized as a triester of Glycerol and C18 iso fatty acids whereas the source substance Glycerides, C14-18 and C16-18 unsaturated, mono-, di- and tri- (CAS 91052-28-7) is a UVCB substance of Glycerol triesterified with mainly C18:1 fatty acids (minor content of C14-18 saturated and C16 unsaturated fatty acids esterified with Glycerol). Thus, both substances are expected to be similar with regard to their toxicity to terrestrial organisms. Moreover, they are likely to have a similar environmental fate based on comparable physico/chemical properties. The source substance does not contain any structural alert function which might increase toxicity to terrestrial organisms.

The target substance has a low water solubility (WS <0.05 mg/L) but a high potential for adsorption (log Koc > 5). The Guidance on information requirements and chemical safety assessment, Chapter R7.b (ECHA, 2012) states that once insoluble chemicals enter a standard STP, they will be extensively removed in the primary settling tank and fat trap and thus, only limited amounts will get in contact with activated sludge organisms. Consequently a significant release to the environment of the substance via STP effluents is not expected and thus an exposure of terrestrial organisms is unlikely. Indirect exposure via irrigation or atmospheric transport is considered to be negligible based on the physico-chemical properties of the substance (water solubility: < 0.05 mg/L; vapour pressure: ≤ 0.000145 Pa at 20 °C).

However, when terrestrial organisms are exposed to the substance toxic effects are not expected as demonstrated by a short-term toxicity study with earthworms available for the analogue substance Glycerides, C14-18 and C16-18 unsaturated, mono-, di- and tri- (CAS 91052-28-7). The toxicity of Glycerides, C14-18 and C16-18 unsaturated, mono-, di- and tri- (CAS 91052-28-7) to earthworms was evaluated by Moser (2012). Eisenia fetida was exposed to the test substance for 14 d at a concentration of 1000 mg/kg dw (limit test). Due to the poor solubility of the substance in water, test solutions were prepared using a solvent. No effects on survival or biomass during the exposure period were reported, leading to a NOEC (14 d) ≥ 1000 mg/kg dw.

Furthermore the available data on the acute and chronic toxicity to aquatic organisms representing three trophic levels (vertebrates, invertebrates and algae) indicates that toxicity to terrestrial organisms is unlikely. As stated in the ECHA Guidance R.7c the absence of chronic or long-term toxicological effects in aquatic organisms up to the substance solubility limit, can be used as part of a Weight of Evidence argument to modify/waive the data requirements of Annex IX and X. Since no effects on Daphnia were observed up to the limit of water solubility in the available chronic toxicity study it is assumed that long term tests on terrestrial organisms will not result in a different outcome. Furthermore, bioaccumulation or biomagnification through the food chain of the substance is not likely. Though the high log Pow value (log Pow: 23.72) indicates a potential of the substance to bioaccumulate a relevant uptake is not likely. Due to a metabolization via enzymatic hydrolysis a relevant uptake and bioaccumulation in terrestrial organisms is not expected. This is supported by low BCF/BAF values (0.893 L/kg; Arnot-Gobas) calculated for the substance indicating a low bioaccumulation potential. Overall, the substance is unlikely to pose a risk to terrestrial organisms based on a) the lack of exposure and b) the lack of adverse effects and low bioaccumulation potential.