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

Toxicity to aquatic algae and cyanobacteria

Description of key information

No effects up to the limit of water solubility.

Additional information

Since no studies investigating the toxicity of Fatty acids, C8-10, C8-10 alkyl esters (CAS 129677-93-6) to aquatic algae 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), Fatty acids, C8-10, C12-18-alkyl esters (CAS 95912-86-0) and Octyl octanoate (CAS 2306-88-9) was conducted. The source substances are representative to evaluate the toxicity of the target substance to aquatic algae. The target substance is characterized as an ester of C8-C10 fatty acid and C8-C10 alcohol. The 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. Fatty acids, C8-10, C12-18-alkyl esters (CAS 95912-86-0) is a UVCB substance of mainly C8-C10 fatty acid esterified with mainly C12-C14 alcohol. Comparing both 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 study with the read-across substance tetradecyl myristate (CAS 3234-85-3) was performed according to OECD 201 (GLP) and investigated the toxicity to freshwater algae (Wenzel, 2012). The green algae Pseudokirchneriella subcapitata was exposed for 72 h to a limit Water Accommodated Fraction (WAF) concentration of nominal 100 mg/L. GC/EI-MS analysis resulted in a measured concentration of 0.142 µg/L (arithmetic mean) over the time of exposure. No effects on growth and yield of algae were observed resulting in an EL50 of > 100 mg/L (nominal) and > 1.465 µg/L (arithmetic mean of measured concentration), respectively. The NOELR was derived to be ≥ 100 mg/L (nominal) and ≥ 1.465 µg/L (arithmetic mean of measured concentrations). 

The second study with Fatty acids, C8 - 10, C12 - 18-alkyl esters (CAS 95912-86-0) was performed according to OECD 201 (GLP) is available investigating the toxicity to aquatic algae (Salinas, 2013). Desmodesmus subspicatus was exposed to nominal loading rates of 10, 32, 100, 320 and 1000 mg/L for 72 h (Water Accommodated Fraction). No effects were observed on growth and yield after 72 h of incubation resulting in an EL50 (72 h) > 1000 mg/L (nominal) and a NOELR (72 h) ≥ 1000 mg/L (nominal).

The third study with the source substance octyl octanoate (CAS 2306-88-9) was conducted according to OECD Guideline 201 and GLP (Caduff, 2013). The test organism Desmodesmus subspicatus was exposed to the test substance at a nominal loading of 100 mg/L, prepared as water soluble fractions (WSF), for 72 h. No significant effect on algal growth was observed. The EL50 (72 h) based on growth rate was determined to be > 100 mg/L and the NOELR (72 h) ≥ 100 mg/L.

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 effects on aquatic algae up to the limit of water solubility.