Decanoic acid, monoester with 1,2,3-propanetriol acetate

Toxicity to soil macroorganisms except arthropods

Description of key information

NOEC (14 d) ≥ 1000 mg/kg dw for Eisenia fetida (OECD 207)

Additional information

No experimental data evaluating the toxicity of Glycerides, C8-21 and C8-21-unsaturated, mono- and di-, acetates (CAS No. 97593-30-1) to soil macroorganisms are available.

Therefore,earthworm toxicity studies conducted on two other Glyceride category members (propane-1,2,3-triyl trisheptanoate (CAS No. 620-67-7) and Glycerides, C14-18 and C16-18 unsatd. mono-, di- and tri- (CAS No. 91052-28-7) are used as read across (in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5). Both read-across substances and the target substance are fatty acid esters of glycerol (in the case of Glycerides, C8-21 and C8-21-unsaturated, mono- and di-, acetates, acetylated fatty acids). All three substances exhibit log Kow/Pow values > 3, indicating high adsorption potential to soil particles. Tests with soil-dwelling organisms that feed on soil particles are therefore most relevant for the evaluation of their soil toxicity. In the absence of a clear indication of selective toxicity, an invertebrate (earthworm or collembolan) test is preferred, as outlined in Guidance on information requirements and chemical safety assessment Chapter R.7.c (ECHA, 2008).  Propane-1,2,3-triyl trisheptanoate represents the lower fatty acid C-chain range within the category (C7, monoconstituent substance), whereas Glycerides, C14-18 and C16-18 unsatd. mono-, di- and tri- represents medium and long fatty acid C-chain lengths (C14-18 and C16-18 unstd.). Glycerides, C8-21 and C8-21-unsaturated, mono- and di-, acetates contains medium fatty acid C-chain lengths, which are covered by the read-across substances. For all three substances, toxicity to aquatic organisms is low, if any. Propane-1,2,3-triyl trisheptanoate and Glycerides, C8-21 and C8-21-unsaturated, mono- and di-, acetates did not show toxicity to aquatic organisms. Glycerides, C14-18 and C16-18 unsatd. mono-, di- and tri- showed no toxicity to fish and aquatic invertebrates (under acute and chronic exposure) up to the limit of its water solubility. Effects on algal growth rate were observed, leading to a NOELR = 32 mg/L (nominal). Nevertheless, since the reported effects occurred well above the water solubility of the substance, physical effects cannot be excluded. Based on their structural similarity and comparable aquatic toxicity profile, it is justified to use the available read-across data to cover this endpoint.

Both tests were performed according to OECD 207, under GLP conditions (Muckle, 2012; Moser, 2012). In both studies, the test organism Eisenia fetida was exposed to the test substance for 14 days at a concentration of 1000 mg/kg dw (limit test). No effects on survival or biomass were reported during the exposure period, leading to NOEC values (14 d) ≥ 1000 mg/kg dw.

 

Glycerides, C8-21 and C8-21-unsaturated, mono- and di-, acetates is readily biodegradable. Therefore, rapid and ultimate degradation in the environment, including soil, can be expected. Chronic exposure of terrestrial organisms is thus very unlikely. Furthermore, this substance did not show acute toxicity to aquatic organisms (fish, aquatic invertebrates and algae) up to a nominal loading rate of 100 mg/L or chronic toxicity up to 10 mg/L (nominal, loading rate). These results indicate no toxicity to terrestrial organisms is expected either. Due to the metabolization via enzymatic hydrolysis of the Glycerides category members, a relevant uptake and bioaccumulation in biota is not expected. Enzymatic breakdown will initially lead to the free fatty acid and glycerol (and for this substance additionally acetic acid). Glycerides are naturally stored by organisms as long-term energy reserves. Especially in periods in which the energy demand is high (reproduction, migration, etc.), glycerides are mobilized from the storage sites as source of fatty acids. Fatty acid catabolism is the most important energy source in many species, resulting in the release of acetyl CoA and NADH (throughβ-oxidation) and eventually, via the tricarboxylic cycle, the production of metabolic energy in the form of ATP. In addition, acetic acid is naturally present in living organisms. The combination of its ionized form (acetate) with coenzyme A (CoA) plays a major role as intermediate in the citric acid cycle (acetyl-CoA). Please refer to IUCLID Section 5.3.1 for a detailed overview on bioaccumulation of the Glycerides category members.

Based on the results obtained for the analogue category members (in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5) and the characteristics of Glycerides, C8-21 and C8-21-unsaturated, mono- and di-, acetates, this substance is not expected to show toxicity to soil macroorganisms