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Toxicity to soil macroorganisms except arthropods

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Description of key information

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

Key value for chemical safety assessment

Additional information

No experimental data evaluating the toxicity Glycerides, C16-18 and C18-unsatd. mono- (CAS No. 91744-09-1) to soil macroorganisms are available. Therefore, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 Grouping of substances, a read-across to the structurally related category members Glycerides, C14-18 and C16-18 unsaturated, mono-, di- and tri- (CAS No. 91052-28-7) was conducted. Further justification is given within the endpoint summary 6.1 and within the category justification section 13. In this case of read-across, the best suited (highest degree of structural similarity, nearest physico-chemical properties) read-across substance within this category was used.

The toxicity of Glycerides, C14-18 and C16-18 unsaturated, mono-, di- and tri- (CAS No. 91052-28-7) to earthworms was evaluated by Moser (2012). Eisenia fetida was exposed to the test substance for 14 days at a concentration of 1000 mg/kg dw (limit test). Due to the poor solubility of the substance in water, test solutions were prepared using a solvent. No effects on survival or biomass during the exposure period were reported, leading to a NOEC (14 d) ≥ 1000 mg/kg dw.

Glycerides, C16-18 and C18-unsatd. mono- (CAS No. 91744-09-1) 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 shows only low toxicity, if at all, to aquatic organisms. 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. 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. 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 structurally related analogue (in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5) and the characteristics of Glycerides, C16-18 and C18-unsatd. mono-, this substance is not expected to show toxicity to soil macroorganisms.