Fatty acids, C8-10, C8-10-alkyl esters

Short-term toxicity to aquatic invertebrates

Description of key information

No effects up to the limit of water solubility.

Additional information

Since no studies investigating the short-term toxicity of Fatty acids, C8-10, C8-10 alkyl esters (CAS 129677-93-6) to aquatic invertebrates are available, in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5 a read-across to the structurally related source substances Tetradecanoic acid, tetradecyl ester (CAS 3234-85-3) and octyl octanoate (CAS 2306-88-9) was conducted. The source substances are representative to evaluate the short-term toxicity of the target substance to aquatic invertebrates. The target substance is characterized as an ester of C8-C10 fatty acid and C8-C10 alcohol. The three source substances are structurally very similar to the target substance. Tetradecanoic acid, tetradecyl ester (CAS 3234-85-3) is a mono-constituent substance consisting of C14 fatty acids esterified with C14 alcohol. Octyl octanoate (CAS 2306-88-9) is a mono-constituent substance of C8 fatty acid esterified with C8 alcohol. Comparing all substances they only differ slightly in C-chain lengths distribution. None of the selected source substances has a structural alert for an increased toxicity via a specific mode of action. This read-across is justified in detail in the overall summary (IUCLID Section 6.1) and within the analogue justification in IUCLID Section 13. In this case of read-across, the best suited (highest degree of structural similarity, nearest physico-chemical properties) read-across substance was used for the assessment.

The first study with the read-across substance tetradecyl myristate (CAS 3234-85-3) was conducted according to OECD 202 (GLP) and investigated the short-term effects to freshwater invertebrates (Schlechtriem, 2012).Daphnia magnawas exposed to a Water Accommodated Fraction (WAF) of nominal 100 mg/L in a limit test for 48 h. GC/EI-MS analysis resulted in a measured geometric mean concentration of 0.128 µg/L. No immobilization was recorded after 48 h resulting in an EL50 of > 0.128 µg/L (measured, geometric mean) and > 100 mg/L (nominal), respectively.

The second study with octyl oleate (CAS 2306-88-9) was performed according to the Appendix of the EU-guideline 92/69/EWG (Wierich, 2000). The test organism Daphnia magna was exposed to the test substance in a static system for 48 h, at nominal test concentrations of 1.0, 3.0, 10, 30 and 100 mg/L. Only the water phase was used for testing, after separation of undissolved test material. The EC50 (48 h) was reported to be >100 mg/L (i.e. greater than the water solubility). However, oil drops were observed on the water surface during test solution preparation. Thus, the dissolved solution was pipetted off to the test vessels. In one case this method may has led to a contamination of test solutions. At a nominal concentration of 10 mg/L daphnids got stuck at the water surface. Since this was a clear physical effect this concentration was not used for the assessment. In contrast the nominal concentrations in excess of 10 mg/L did not cause effects on mobility.

Based on the available results from structurally related read-across substances (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which are characterized by a similar ecotoxicological profile and comparable structure, it can be concluded that Fatty acids, C8-10, C8-10 alkyl esters will not exhibit short-term effects to aquatic invertebrates up to the limit of water solubility.