10-Undecenoic acid, monoester with 1,2,3-propanetriol

Short-term toxicity to fish

Description of key information

No toxic effects on fish up to the limit of water solubility

Additional information

Data on the acute toxicity of Glyceryl undecylenate (CAS 123759-97-7) to fish is not available. The assessment was therefore based on a study conducted with the structurally similar substances Glycerides, C8-10, mono- and di- (CAS 85536-07-8) and Glycerides, C14-18 and C16-18-unsatd. mono-, di- and tri- (CAS 91052-28-7), as part of a read across approach, which is in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5. Further justification is given within the overall summary chapter 6.1 and within the analogue justification section 13.

The acute toxicity of Glycerides, C8-C10, mono- and di- (CAS 85536-07-8) to fish was investigated by Hafner (2013). Danio rerio was exposed to the test substance in a preliminary limit test at 100 mg/L (loading rate). Six out of seven test organisms died after 48 hours. Therefore, for the definitive test, a range of nominal loading rates from 6.25 to 100 mg/L were prepared. Analytical measurement of the highest (100 mg/L) and middle (25 mg/L) loadings was performed via TOC and DOC analysis. Initial concentrations in these two vessels resulted in values of 21.9 mg/L and 11.5 mg/L (DOC). Nevertheless, inconsistent results were obtained when comparing start and final concentrations and, according to the authors, should be taken with caution.
Danio rerio was exposed to the test substance for 96 hours within a static water regime. After the exposure period, 100% mortality was reported at the highest loading rate of 100 mg/L, whereas no mortality was observed in any other treatment group, leading to a LL50 (96 h) of 75 mg/L (nominal, loading rate).
Nevertheless, the observed effects occurred above the water solubility of the substance, and seem to be caused by direct physical interference of test material particles with fish, rather than due to intrinsic toxicity of the substance itself. For both preliminary and final tests Water Accommodated Fractions (WAFs) were prepared by adding the test material into water, stirring for a period of 48 hours, followed by a sedimentation period of 1 hour. After the sedimentation period, the 100 mg/L loading rate appeared to be turbid, containing visible oil drops. The test solutions were prepared without a filtration step. According to the reported results, fishes in this vessel were strongly affected already after 24 h, swimming slowly and laying in the bottom of the aquarium. One fish also swam on the surface and gasped. Considering the above information, undissolved test material present at this loading rate could be responsible for the observed effects (via gill clogging). This statement is supported by the observations made in the acute tests conducted with aquatic invertebrates and algae, for which physical effects cannot be excluded either.
Scientific evidence showed that aquatic toxicity testing of this type of Glycerides is technically very difficult (Prajapati et al. , 2012; see IUCLID section 6.1.4). Though clear or translucent solutions might be observed when testing medium-chain (C8-10) mono-, di- and triglycerides , microemulsions might be present. Glycerides, C8-10 mono- and di- contains mixed mono and diester C8-10 fatty acids and formation of microemulsions in test solutions is therefore possible for this substance.
Although the effect values of the study should be taken with caution, due to probable physical effects, it can be concluded that no mortality occurred up to a concentration of 50 mg/L, which is above the water solubility limit of the substance. Therefore, no toxicity of Glycerides, C8-C10, mono- and di- (CAS 85536-07-8) to fish species up to the limit of the water solubility is expected.

The second read-across study evaluating the acute toxicity of Glycerides,C14-18 and C16-18 unsaturated, mono-, di- and tri- (CAS 91052-28-7) was performed according to the German national Guideline DIN 38412/15. In this static test, fish (Leuciscus idus) were exposed to the test substance for 48 hours. After this period, no mortality or any other effects were reported at any of the concentrations tested (LC50 (48 h) > 10000 mg/L). According to the Guidance on information requirements and chemical safety assessment, chapter R7.b, results obtained at shorter test durations than the standard 96 hours (OECD 203) should be treated with caution and always in combination with other data (read-across, non-testing, etc.). Therefore, a Weight of Evidence (WoE) approach is applied to cover this endpoint adequately (in accordance with Regulation (EC) No 1907/2006, Annex XI, 1.2).

Based on the results for the read-across substances, Glyceryl undecylenate (CAS 123759-97-7) is considered not toxic to fish within the limit of water solubility.