Isopentyl oleate

Endpoint summary

Additional information

The dataset investigating the environmental fate of Isopentyl oleate (CAS 627-89-4) is no complete. Data on the ready biodegradability of Isopentyl oleate (CAS 627-89-4) are not available. In order to fulfil the standard information requirements set out in Annex VII, 8.5, in accordance with Annex XI, 1.5, of Regulation (EC) No 1907/2006, read-across from the structurally related substances Isopentyl laurate (CAS 6309-51-9) and Isopropyl oleate (CAS 112-11-8) was conducted. Isopentyl oleate (CAS 627-89-4) is an UVCB substance comprising saturated and unsaturated linear C16-C18 fatty acids esterified with a branched C5 alcohol. The source substance Isopentyl laurate (CAS 6309-51-9), is a branched C5 alcohol esterified with a linear C12 fatty acid chain. Whereas Isopropyl oleate (CAS 112-11-8) is a branched C3 alcohol esterified with saturated and unsaturated linear C14-C18 fatty acid chains. The read across substances cover the alcohol moiety as well as the longest and shortest fatty acid chains of the target substance.

Based on the results determined for the source substances, the target substance Isopentyl oleate (CAS 627-89-4) is considered readily biodegradable (OECD 301 B, 100% in 28 d) according to the OECD criteria. Due to the ready biodegradability, persistency of the substance in the environment is not expected. Abiotic degradation by hydrolysis is not relevant for the substance as indicated by QSAR calculations resulting in estimated half-lives in water of 331.88 days at pH 7 and 9.09 years at pH 8 respectively. The substance is furthermore characterised by a low water solubility (< 3 µg/L at 20 °C) and a low vapour pressure (<0.0001 Pa at 20 °C). The log Koc values calculated for the single substance components are >5. The characteristics indicate that the substance would mainly distribute to soil and sediment when released to the environment.

However, an exposure of these environmental compartments is unlikely, since the substance is expected to be extensively eliminated in conventional sewage treatment plants. In the case insoluble chemicals enter a standard Sewage Treatment Plant (STP), they will be largely removed in the primary settling tank and fat trap and thus, only limited amounts will get in contact with activated sludge organisms (Guidance on information requirements and chemical safety assessment, Chapter R.7b; ECHA, 2016). The substance is generally not expected to be present in the water column due to the low water solubility. The log Koc values indicate a potential for adsorption to sewage sludge. Thus, further reduction of the substance concentration in the water column due to adsorption is possible (Guidance on information requirements and chemical safety assessment, Chapter R.7b; ECHA, 2016). Based on the ready biodegradability and substance characteristics the substance concentration in conventional STP effluents is expected to be negligible.

The volatilization potential of the substance is very low (VP < 0.0001 Pa at 20°C). An accumulation in air, subsequent transportation and deposition into other environmental compartments is not expected.

Due to the rapid environmental biodegradation and metabolization of the substance via enzymatic hydrolysis a relevant uptake and bioaccumulation in aquatic organisms is not expected. Enzymatic breakdown will initially lead to the free fatty acid and a primary branched alcohol. These hydrolysis products will be metabolised and excreted in fish effectively (Tocher, 2003). The low bioaccumulation potential is also indicated by BCF values ranging from 2.113 - 10.63 L/kg (BAF 137 – 2870 L/kg) calculated for the main components of the substance (BCFBAF v3.01, Arnot-Gobas, including biotransformation, upper trophic).

References:

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