Fatty acids, coco, 2-ethylhexyl esters

Short-term toxicity to aquatic invertebrates

Description of key information

No effects up to the limit of water solubility for Daphnia magna (EU Method C.2)

Additional information

Only an unreliable study is available on the toxicity of Fatty acids, coco, 2-ethylhexyl esters (CAS No. 92044-87-6) to aquatic invertebrates. The assessment of short-term toxicity was therefore based on a studies conducted with the structurally most similar category members, for which valid data is available, isopropyl myristate (CAS No. 110-27-0) and isopropyl palmitate (CAS No. 142-91-6). This read across approach is in accordance with Regulation (EC) No 1907/2006, Annex XI, 1.5. Grouping of substance and read across approach. Further justification is given within the endpoint summary 6.1 and within the category justification in Section 13. In this case of read-across, the best suited (highest degree of structural similarity, nearest physico-chemical properties) read-across substance was entered into IUCLID. Nevertheless, as can be seen in the data matrix of the category justification in Section 13, all reliable data in the category support the hazard assessment for this endpoint, by showing a consistent pattern of results.

The disregarded study with Fatty acids, coco, 2-ethylhexyl esters (CAS No. 92044-87-6) was performed according to OECD guideline 202 (Handley, 1992). The test organism Daphnia magna was exposed to the test substance in a static system for 48 hours, at the nominal test concentrations of 0.010, 0.018, 0.032, 0.056, 0.10, 0.18, 0.32, 0.56 and 1.0 mg/L. Tween 80-acetone was used as solvent for the test solutions. The use of solvents is not appropriate, since the test substance is a UVCB, and the use of a solvent can give preferential dissolution of one or more constituents. The test is therefore considered unreliable. Additionally, the resulting EC50 value of 0.31 mg/L is much lower than expected from all other data available for similar substances in the category, which all lie above the water solubility of the test substance. Even in long-term studies with Daphnia magna no effects were observed up to the limit of water solubility. This indicates that the toxicity observed in this test is probably due to effects induced by the solvent used, e.g. unproportionally high dissolution of a minor constituent. This result was therefore disregarded for the assessment.

The key study with isopropyl myristate (CAS No. 110-27-0) was performed as a limit test according to EU Method C.2 and GLP (Stelter, 1995). The test organism Daphnia magna was exposed to the test substance in a static system for 48 hours. Three different methods were used for the preparation of test solutions: 1) direct addition to 100 mg/L, 2) direct addition to 100 mg/L with removal of undissolved test substance and 3) 3-5 times saturation without separation of undissolved material. With the first method an oil film was observed at the surface, and up to 100% immobilisation occurred. With the other two methods, no significant effect was observed. Based on the results, the observed immobilisation is most probably due to physical effects caused by undissolved test substance. It can therefore be concluded that the test substance had no significant toxic effect on the test organism up to the limit of water solubility. An EC50 of > 0.05 mg/L was reported.

The key study with isopropyl palmitate (CAS No. 142-91-6), used as key study, was performed according to EU Method C.2 and GLP (Kirch, 1998). The test organism Daphnia magna was exposed to the test substance in a static system for 48 hours, at nominal test concentrations of 1000 and 3000 mg/L (measured initial concentrations 0.72 and 1.68 mg/L). No mortalities were observed at any of the test concentrations, and an EC50 of > 3000 mg/L was reported.

Thus, based on theabove mentioned result, and due to the structural and profile similarities of the two substances, as are explained within the overall endpoint summary 6.1 it can be concluded that no toxicological short-term effects on aquatic invertebrates are expected up tothe limit ofwater solubility for Fatty acids, coco, 2-ethylhexyl esters (CAS No. 92044-87-6).