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Ecotoxicological information

Short-term toxicity to aquatic invertebrates

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Administrative data

Link to relevant study record(s)

Description of key information

No effects up to limit of water solubility (WS < 1 mg/L)

Key value for chemical safety assessment

Additional information

No experimental data evaluating the acute toxicity of Fatty acids, C16-C18, methyl esters (CAS No. 85586-21-6) to aquatic invertebrates are available. Therefore, toxicity data from structurally similar category members, Fatty acids, C16-18 and C18 unsaturated, methyl esters (CAS No. 67762-38-3), Fatty acids C16-18 unstd., methyl esters (CAS No. 67762-26-9) and methyl myristate (CAS No. 124-10-7) are used as read-across in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5. All four substances are fatty acids esterified with methanol, containing fatty acid C-chain lengths of C14 (CAS No. 124-10-7) and C16-18 (saturated and unsaturated) (CAS No. 67762-38-3, 67762-26-9 and the target substance, CAS No. 85586-21-6) respectively.The C14 substance (CAS No. 124-10-7) was chosen as read-across substance as monoconstituent representative of medium-to-high fatty acid chain lengths within the category (insoluble substances). This substance, even when comparable to the target substance, has a shorter fatty acid C-chain length and due to this fact, the molecular size and weight will be lower than those of CAS No. 85586-21-6. For these reasons, methyl myristate can be expected to be more bioavailable to aquatic organisms and can be regarded as a worst-case read-across for Fatty acids, C16-18, methyl esters (CAS No. 85586-21-6).The log Pow (> 5 for all substances) and water solubility values (0.05 mg/L for CAS No. 124-10-7, < 0.05 mg/L for CAS No. 67762-38-3 and < 1 mg/L for CAS No. 67762-26-9 and CAS No. 85586-21-6) of these four substances indicate that, besides the structural similarities that will lead to similar toxicity profiles, a comparable behaviour in water for all of them can be expected. Based on this information, it is justified to use the toxicity data from the analogues as read-across for Fatty acids, C16-C18, methyl esters, according to Regulation (EC) No. 1907/2006, Annex XI, 1.5.

One study evaluating the acute toxicity of methyl myristate (CAS No. 124-10-7) to aquatic invertebrates is available (Migchielsen, 2010). This test was performed according to OECD Guideline 202, under GLP conditions. Daphnids were exposed to the test substance for 48 hours within a semi-static water regime, at a 100 mg/L loading rate and subsequent dilutions. Analytical determinations of test concentrations in the solution were performed during the test. Due to the insolubility of the substance in water (0.05 mg/L), the test substance concentration could only be detected after the 24-h water renewal, being 0.02 mg/L. After 48 hours, no significant effects were observed at the concentration tested and therefore, the EC50 (48 h) was determined to be > 100 mg/L (nominal, filtered solution) and > 0.02 mg/L (measured initial concentration).


The test available for Fatty acids C16-18 unstd., methyl esters (CAS No. 67762-26-9) was performed according to EU Method C.2, under GLP conditions (Kuch, 1996). In this static test,Daphnia magnawas exposed to the test substance for 48 h in two solutions: one in which the test substance was directly added to the medium and a Water Accommodated Fraction (WAF). Effects on mobility were recorded every 24 hours. No significant immobilization was observed in any of the treatment groups and therefore the EC50 and EL50 (48 h) were > 100 mg/L (nominal).


Additionally, a marine test was conducted with Fatty acids, C16-18 and C18 unsaturated, methyl esters (CAS No. 67762-38-3) according to the ISO Proposal: Determination of acute lethal toxicity to marine adult copepods (Acartia tonsa DANA), under GLP conditions (Hudson, 1998).Acartia tonsawas exposed for 48 h to the test substance within a static water regime. After the exposure period, the EL50 (48 h) was determined to be > 1000 mg/L (nominal, loading rate).

Based on the results obtained for the structurally related category members (according to Regulation (EC) No. 1907/2006, Annex XI, 1.5), Fatty acids, C16-C18, methyl esters (CAS No. 85586-21-6) is not expected to show acute toxicity to aquatic invertebrate species up to the limit of its water solubility (< 1 mg/L).