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Long-term toxicity to aquatic invertebrates

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Description of key information

No effect on long-term toxicity to aquatic invertebrates up to the limit of water solubility.

Key value for chemical safety assessment

Additional information

Several long-term freshwater studies on Daphnia magna according to OECD 202 are available for the SCAE C2-C8 category. No effects were observed up to the limit of water solubility and a NOEC(21 d) >1 mg/L could be stated.

No studies on the long-term toxicity of Fatty acids, C16-18, 2-ethylhexyl esters are avilable.

Key studies are therefore taken from the read-across substances 2-ethylhexyl oleate (CAS 26399-02-0) and Fatty acids, C8-16, 2-ethylhexyl esters (CAS 135800-37-2).

The study with the read across 2 -ethylhexyl oleate investigated the long-term effects to the freshwater invertebrate Daphnia magna (Kuech 1995). The study was performed according to the OECD guideline 202, part 2 of 1993. Test concentrations of nominal 1 and 100 mg/L were appplied as filtered test solutions. Analytically, concentrations of <0.01 mg/L were retrieved from both nominal concentrations. Effects to Daphnia magna were observed after 21 days with no effect at 1 mg/L and 90% mortality (on day 19) at 100 mg/L. The authors stated, that the deaths in the higher concentration could be attributed to sample contamination. Therefore, a NOEC(21 d, mortality)1 mg/L (nominal) was reported. Similarly, 23% reduction of reproduction (number of offspring) in the 100 mg/L sample occurred after 21 days, with no effect in the 1 mg/L sample resulting in a NOEC(21 d, reproduction) > 1 mg/L. If the reproduction up to day 17 in the 100 mg/L sample was compared to the reproduction in the control, no reduction of reproduction was stated.

To substantiate this key study findings, a further study was taken as read-across with Fatty acids, C8-16, 2-ethylhexyl esters (Wierich 1998). 1 and 100 mg/L test substance were both tested as filtered test solutions. In the filtered solution of 1 mg/L no effects on Daphnia magna were observed for mortality and reproduction, on the other hand, in the filtered solution of 100 mg/L a significant reduction of the reproduction was stated. The authors supposed that the effects in the 100 mg/L filtered test solution are due to a better water soluble by-compound (for example a short chain fatty acid ester) or - less likely due to a toxic impurity. Therefore, a NOEC(21d, reproduction) of > 1 mg/L (nominal) was given.