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Ecotoxicological information

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Experimental data on the aquatic toxicity of Nonanoic acid, esters with adipic acid and trimethylolpropane are available for aquatic algae. The available study on toxicity of the substance to Raphidocelis subcapitata determined no adverse effects of the substance on algal growth (NOELR (72 h) ≥ 100.5 mg/L (nominal), OECD 201).

The assessment of the acute toxicity to fish and aquatic invertebrates is based on a read-across approach. In accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across to the structurally related substance Fatty acids, C8-10, mixed esters with adipic acid and trimethylolpropane (CAS 95912-89-3) was conducted to fulfill the information requirements for acute toxicity to fish and aquatic invertebrates.In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular for aquatic toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across). According to Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 substances can be considered similar if their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity.

The target substance and the source substance are UVCB substances consisting of a polyfunctional alcohol containing three hydroxyl groups (trimethylolpropane) esterified with linear satured fatty acid chains.The substances result from esterification of the alcohol with the respective fatty acid(s). Esterification is, in principle, a reversible reaction (hydrolysis). Thus, in theory the alcohol, dicarboxylic acid and fatty acid moieties are simultaneously precursors and breakdown products of the target and source substances.The target and the source substance are characterised by a low water solubility (WS<0.05 mg/L), low vapour pressure (<0.001 Pa at 20 °C) and high log Koc values (log Koc >5 (MCI method)). Both, target and the source substance are readily biodegradable. Thus, the substances are expected to have a similar environmental fate and ecotoxicity profile. A detailed justification of the Analogue Approach is attached in IUCLID section 13.

The available acute toxicity studies on the source substance Fatty acids, C8-10, mixed esters with adipic acid and trimethylolpropane (CAS 95912-89-3) determined no detrimental effects on fish or aquatic invertebrates. The reported LL50 (96 h) for Danio rerio was > 1000 mg/ nominal loading rate (WAF) (OECD 203). In the acute toxicity study on Daphnia magna an EL50 (48 h) of > 100 mg/L nominal loading rate (WAF) was reported (OECD 202). 

Studies on the toxicity of the target substance Nonanoic acid, esters with adipic acid and trimethylolpropane to microorganisms are not available. The assessment is therefore based on the inhibition control of the available biodegradation study according to OECD 301B in accordance with ECHA Guidance R.7b (ECHA, 2017). The inhibition control attained 71 % degradation after 14 days of incubation. Therefore the substance is considered not toxic to aquatic microorganisms and the test item concentration of 53.08 mg/L was used as NOEC (NOEC (14 d) ≥ 53.03 mg/L).