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Environmental fate & pathways

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Based on test results Fatty acids, C18-unsatd., dimers, 2-ethylhexylesters (CAS No. 68334-05-4) can be regarded as readily biodegradable. Therefore, the substance will not persistent in the environment. 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-unsatd., dimers, 2-ethylhexylesters is high (log Koc > 5, KOCWIN v2.00). Hence, soil and sediment are expected to be the main targets for environmental distribution. Nevertheless, perstistency in these compartments is not expected since the substance is readily biodegradable and it will be therefore ultimately degraded in sewage treatment plants. 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 OH-radicals with a DT50 of 2.2 h – 2.3 h (AOPWIN v1.92).

Furthermore, it can be concluded that the bioaccumulation potential of Fatty acids, C18-unsatd., dimers, 2-ethylhexylesters is negligible since the low water solubility (< 1 mg/L), readily biodegradability and high adsorption potential (log Koc > 5) reduce the availability of the substance in water. Furthermore, the high molecular weight (673 g/mol) reducing significantly the absorption into organisms due to steric hindrance to cross biological membranes. 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.