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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

Experimental studies are available, in which the aquatic toxicity of the target substance Fatty acids, C18-unsaturated, 2-hexyldecyl ester was investigated according to OECD guidelines. However, since the key studies conducted with the target substance were not GLP compliant, read-across was performed to two structurally and chemically closely related source substances for which GLP-guideline studies are available, in order to support the key findings and to fulfill the standard information requirements laid down in Annex VII of the REACh Regulation (EC) No. 1907/2006. Read-across was conducted in accordance with Regulation (EC) No 1907/2006 Annex XI, 1.5.

According to Article 13 (1) of this regulation, "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.” For aquatic toxicity in particular, 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). In regard to the general rules for grouping of substances and the read-across approach, the regulation specifies (Annex XI, Item 1.5) that 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.

Based on the structural and physico-chemical similarity between the target and the selected source substances, the target substance is expected to have a similar ecotoxicological profile as the selected source substances. The source substances are characterized by similar fatty acid esters and are therefore considered suitable representatives for the assessment of the aquatic toxicity of the target substance. A detailed justification of the analogue approach is provided in IUCLID section 13.


The key study for the short-term toxicity of the target substance to aquatic invertebrates resulted in no effects up to the limit of water solubility of the substance (EL50 (48 h) > 0.104 g/L, OECD 202). This result is confirmed by the supporting study with the source substance Fatty acids, C16-18, 2-hexyldecyl esters, CAS 101227-09-2 (EL50 (48 h) > 1000 mg/L).

Due to the extremely low water solubility of the target substance (< 0.56 µg/L), long-term testing on aquatic invertebrates was considered necessary to fully assess the potential aquatic hazard. The available read-across study for chronic toxicity to aquatic invertebrates was performed with the source substance 2-octyldodecyl isooctadecanoate (CAS 93803-87-3).

No experimental results were obtained due to technical challenges resulting from the physico-chemical properties of the source substance and a statement was provided by the testing facility instead. Owing to the fact that the source substance is a liquid with water solubility below the limit of detection (< 0.05 mg/L) and a log Kow of > 7.0, it was not possible to prepare solutions of the test item that could be tested in a 21-d reproduction test with D. magna. Moreover, these properties suggest it is highly unlikely that bioavailable concentrations of the test item will ever occur in the water phase, i.e. that concentrations high enough to induce any acute or chronic effects in aquatic organisms are highly unlikely to be attained. Therefore, no chronic test with invertebrates could be conducted for this source substance. Since the target substance is closely related to this source substance, the testing of the target substance will likely face similar technical challenges.

The key study for the toxicity of the target substance to aquatic algae resulted in no effects up to the limit of water solubility (EL50 (72 h) > 0.104 g/L, OECD 201). This finding is confirmed by the supporting study with source substance 2-octyldodecyl isooctanoate, CAS 93803-87-3 (EL50 (72 h) and NOELR (72 h) both > 100 mg/L, OECD 201).

In summary, the compiled data for the short-term and long-term toxicity of the target and source substances to aquatic organisms neither indicates any short-term nor any long-term toxicity to aquatic organisms up to the limit of water solubility of the substances. Moreover, the target substance is expected to be eliminated from sewage treatment plants to a high extent, due to its ready biodegradability and high adsorption potential. Therefore, release to the aquatic compartment and subsequent exposure of sediment is highly unlikely. Against this background, the potential for chronic exposure is judged to be very low.

Therefore, it is concluded that the target substance Fatty acids, C18-unsaturated, 2-hexyldecyl ester does not exhibit short-term or long-term effects to aquatic organisms up to the limit of water solubility (< 0.56 µg/L).