Tetradecyl oleate

Long-term toxicity to aquatic invertebrates

Description of key information

No effects up to the limit of water solubility based on available data (OECD 202, part 2; OECD 211).

Additional information

Since no studies investigating the long-term toxicity to aquatic invertebrates of tetradecyl oleate (CAS 22393-85-7)are available for this endpoint, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read across to the two structurally related category members 2-ethylhexyl oleate (CAS 26399-02-0) and dodecyl oleate (CAS 36078-10-1) was conducted. Both read-across substances are characterized by the same fatty acid (C18 unsatd.) and an alcohol component of C8 or C12, respectively. The target substance is characterized by a C18 unsatd. fatty acid and a C14 alcohol component which is very similar to the composition of the read-across substances. The smaller alcohol chain length increases the water solubility and therefore the bioavailability in the water. Water solubility is negatively correlated with the C-chain length of the fatty alcohol and fatty acid (Lide, 2005). Therefore, it is possible to extrapolate from a category member with higher water solubility since it has an increased bioavailability in the water phase (ECHA, 2008). This read-across is justified in detail in the overall summary (IUCLID chapter 6.1) and within the category 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. Nevertheless, as it can be seen in the data matrix of the category justification in section 13 and the overall summary, all reliable data in the category support the hazard assessment of each category member by showing a consistent pattern of results.

The study with the read-across substance 2-ethylhexyl oleate was performed according to OECD 202, part 2 (1993) under GLP conditions (Küch, 1995). Daphnia magna was exposed to two nominal concentrations (1 and 100 mg/L) which were both measured to be < 0.01 mg/L indicating similar concentrations in both test vessels. Effects to Daphnia magna were observed after 21 d with 90% mortality (on day 19) at 100 mg/L and no effects at 1 mg/L. The authors stated, that the mortality in the higher concentration could be attributed to sample contamination. 23% reduction of reproduction in the 100 mg/L sample occurred after 21 d, whereas no effects were observed at 1 mg/L resulting in a NOEC (21 d) ≥ 1 mg/L. The nominal concentration of 100 mg/L was not taken into account for the assessment due to the possible contamination of test solutions.

The second study with the read-across substance dodecyl oleate (CAS 36078-10-1) was performed according to OECD 211 under GLP conditions with the water flea Daphnia magna (Brunswik-Titze, 2013). Five nominal concentrations up to 100 mg/L were tested in a semi-static exposure system as Water Accommodated Fractions (WAF). No effects on the reproduction of D. magna were observed after 21 d. One dead animal was recorded at 50 mg/L but it was reported that it was no substance specific effect (accident during medium change). Therefore, a NOELR (21 d) of ≥ 100 mg/L (nominal) was derived. The chemical analysis resulted in concentrations below the analytical detection limit of 0.005 mg/L reflecting the very low water solubility of the test item.

Based on the available result from two 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 tetradecyl oleate will not exhibit long-term effects on aquatic invertebrates up to the limit of water solubility.