Fatty acids, C18 unsaturated, ethyl & methyl esters

Endpoint summary

Additional information

Experimental data on the biodegradability of Fatty acids, C18 unsaturated, ethyl & methyl esters (EC 941-981-3) are not available.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 the assessment of biodegradability is based on data available for the read across substances methyl oleate (CAS 112-62-9) and Fatty acids, safflower-oil, ethyl esters (CAS 91051-53-5). Fatty acids, C18 unsaturated, ethyl & methyl esters (EC 941-981-3) is an UVCB substance consisting of ethanol and methanol esterified with poly- and monounsaturated C18 fatty acids. The source substances methyl oleate (CAS 112-62-9) is a main constituents of the target substance. Methyl oleate is a methylalcohol esterified with a linear, monounsaturated fatty acid chain. The source substance Fatty acids, safflower-oil, ethyl esters (CAS 91051-53-5) is a C2 alcohole esterified with a linear, poly-unsaturated fatty acid chain with two double bonds. Based on the results determined for the source substances, the target substance Fatty acids, C18 unsaturated, ethyl & methyl esters (EC 941-981-3) is considered readily biodegradable (≥ 69% in 28 d; OECD 301B) 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. The estimated half-lives of the main substance components were >7 years at pH 7 and ≥ 266 days at pH 8 respectively. The substance is furthermore characterised by low water solubility (WS ≥0.021 mg/L), a low vapour pressure (<0.001 Pa) and a high log Koc value (log Koc: 4.68 – 4.94). Based on these characteristics a distribution to soil and sediment is most likely in case of release 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, 2014). 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, 2014). Thus based on the ready biodegradability and substance characteristics the substance concentration in conventional STP effluents is expected to be neglectible.

The volatilization potential of the substance is very low (VP: <0.001 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 lead to the free fatty acid and an alcohole. These hydrolysis products will be metabolised and excreted in fish effectively (Tocher, 2003). A low bioaccumulation potential is also indicated by BCF values <2000 L/kg calculated for the main substance components.