Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

One key study performed according to OECD 301B confirmed that Fatty acids, C18 unsaturated, trimers, 2-ethylhexyl esters (CAS No. 173832-46-7) is not readily biodegradable according to OECD criteria. Therefore, persistence of this substance in the environment cannot be excluded. The degradation via abiotic hydrolysis is not considered to be a relevant degradation pathway in the environment since QSAR results using HYDROWIN v2.00 resulted in DT50 values > 1 yr at pH 7.

The adsorption potential for Fatty acids, C18 unsaturated, trimers, 2-ethylhexyl esters is high (log Koc >5, KOCWIN v2.00). Hence, soil and sediment are expected to be the main targets for environmental distribution. Evaporation into air and the transport through the atmospheric compartment is not expected since the substance is not volatile based on the low vapour pressure of <0.0001 Pa at 20 °C. Accumulation in air and the subsequent transport to other environmental compartments is not anticipated. However, if released into air, the substance is susceptible to indirect photodegradation by reaction with OH-radicals with a DT50 ranging from 2.06 h to 2.32 h (AOPWIN v1.92).

Furthermore, it can be concluded that the bioaccumulation potential of Fatty acids, C18 unsaturated, trimers, 2-ethylhexyl esters is negligible since the low water solubility (< 1 mg/L) and high adsorption potential (log Koc > 5) reduce the availability of the substance in water. Furthermore, the high molecular weight (973.62 - 11184 g/mol) reduces significantly the absorption into organisms due to steric hindrance to cross biological membranes. Generally, substances with log Kow > 10, such as Fatty acids, C18 unsaturated, trimers, 2-ethylhexyl esters, are expected to have BCF values < 2000 L/kg (Guidance on information requirements and chemical safety assessment, Chapter 11 (ECHA, 2012). Calculated BCF/BAF values ((BCF: 0.89 L/kg; BAF: 0.89 L/kg; Arnot-Gobas estimate, upper trophic; BCFBAF v3.01) support this assumption.