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Environmental fate & pathways

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One experimental study according to OECD 301D confirmed that Isononanoic acid, C16-18 alkyl esters (CAS 111937-03-2) is readily biodegradable according to the OECD criteria (86% biodegradation after 30 d). 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. Considering its physico-chemical properties like the low water solubility (< 0.05 mg/L) and the potential for adsorption to organic particles (log Koc: > 5, KOCWIN v2.00), the main compartment for environmental distribution is expected to be the soil and sediment. Nevertheless, persistency in these compartments is not expected since the substance is readily biodegradable and it will be rapidly and ultimately degraded in sewage treatment plants and natural waters. Moreover, an exposure to the soil can be excluded based on the identified uses (see IUCLID Section 3.5).Evaporation from the water phase into air and the transport through the atmospheric compartment is not expected in significant amounts for Isononanoic acid, C16-18 alkyl esters based on the low vapour pressure of 0.0095 Pa. However, if released into air, Isononanoic acid, C16-18 alkyl esters is susceptible to indirect photodegradation by OH-radicals with a DT50 value of 13.20 - 14.61 h (AOPWIN v1.92). Therefore, the potential for accumulation in air and the subsequent transport to other environmental compartments is low. Due to the low exposure in the water phase (low water solubility), rapid environmental biodegradation and metabolisation via enzymatic hydrolysis of Isononanoic acid, C16-18 alkyl esters, a relevant uptake and bioaccumulation in aquatic organisms is not expected. Enzymatic breakdown will initially lead to the free isononanoic acid and the free alcohol (mainly C16-C18). From literature it is well known, that these hydrolysis products will be metabolised and excreted in fish effectively (Heymann, 1980; Lech & Bend, 1980; Lech & Melancon, 1980; Murphy & Lutenske, 1990; Lehninger, 1993). This is supported by low calculated BCF values of 0.9547 - 1.217 L/kg ww (BCFBAF v3.01, Arnot-Gobas, including biotransformation, upper trophic; Müller, 2011). Please refer to IUCLID Section 5.3 for a detailed overview on bioaccumulation of Isononanoic acid, C16-18 alkyl esters.

A detailed reference list is provided in the technical dossier (see IUCLID, section 13) and within CSR.