Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Considering the low water solubility (< 0.05 mg/L) and the potential for adsorption to organic soil and sediment particles (log Koc: 3.79 - 4.33, MCI method, KOCWIN v2.00), the main compartments for environmental distribution are expected to be the soil and sediment based on their intrinsic properties. Nevertheless, persistency in these compartments is not expected since isononyl isononanoate is readily biodegradable according to the OECD criteria in one experimental study (91% biodegradation after 28 d). Therefore, it is assumed that the substance is eliminated in sewage treatment plants to a high extent. Furthermore, high adsorption potential promotes rapid removal from waste water. If fractions of this chemical were to be released in the aquatic environment, the concentration in the water phase will be reduced by rapid biodegradation and potential of adsorption to solid particles and to sediment. 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 > 1 yr at pH 7. Evaporation into air and the transport through the atmospheric compartment is not expected since isononyl isononanoate is not volatile based on the low vapour pressure (0.00398 - 0.0447 Pa). 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: ≤ 24 h (AOPWIN v1.92). Due to the low water solubility and rapid environmental biodegradation a relevant uptake and bioaccumulation in aquatic organisms is not expected. This is supported by low calculated BCF values of 113.1 - 484.3 L/kg ww (BCFBAF v3.01, Arnot-Gobas, including biotransformation, upper trophic; Müller, 2012) indicating a low bioaccumulation potential.