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Fatty acids, C18-unsatd., dimers, reaction products with fatty acids, C14-18 and C16-18-unsatd. and propylidynemethanol (CAS 162353-70-0) is characterised by a low vapour pressure (VP < 0.0001 Pa at 20 °C, SPARC (v4.6)), a low water solubility (< 25 µg/L at 20 °C, pH = 6.3) and a a high log Koc (log Koc > 5, MCI method, KOCWIN v2.00).

Data on the ready biodegradability ofFatty acids, C18-unsatd., dimers, reaction products with fatty acids, C14-18 and C16-18-unsatd. and propylidynemethanolare 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, read-across from the structurally related substancesFatty acids, C18-unsatd., dimers, mixed esters with oleic acid and trimethylolpropane (CAS 147256-33-5) and Fatty acids, C16-18 and C18-unsatd., triesters with trimethylolpropane (CAS 68002-78-8) was conducted.

The target substance Fatty acids, C18-unsatd., dimers, reaction products with fatty acids, C14-18 and C16-18-unsatd. and propylidynemethanol (CAS 162353-70-0) mainly consists of mixed esters (mono-, di- or tri-component) of fatty acid dimers of predominantly octadecenoic acid (C18 unsaturated) and octadecenoic acid with propylidynemethanol. Fatty acids, C18-unsatd., dimers, mixed esters with oleic acid and trimethylolpropane (CAS 147256-33-5) is also an ester of the C18-unsatd. dimerised fatty acid and oleic acid with trimethylolpropane. Whereas Fatty acids, C16-18 and C18-unsatd., triesters with trimethylolpropane (CAS 68002-78-8) is a triester with trimethylolpropane esterified with C16-C18 saturated and C18 unsaturated fatty acids.

Based on the results determined for the source substances, the target substanceFatty acids, C18-unsatd., dimers, reaction products with fatty acids, C14-18 and C16-18-unsatd. and propylidynemethanolis considered readily biodegradable (OECD 301 F; 70% 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 experimental data on the analogue substance Fatty acids, C18 unsaturated, dimers, fatty acids C18:1 unsaturated, polyesters with trimethylolpropane (CAS 147256-33-5) and QSAR calculations conducted with the main substance components of the target substance. The QSAR calculations estimated half-lives in water for the main substance components of >5 years at pH 7 and >200 d at pH 8. The low water solubility of the substance (< 25 µg/L at 20 °C, pH = 6.3) and high log Koc values calculated for the single substance components indicate that the substance would mainly distribute to soil and sediment when released to the environment. A distribution to the air is not expected based on the low vapour pressure (VP < 0.0001 Pa at 20 °C, SPARC (v4.6)).

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). Thus based on the ready biodegradability and substance characteristics the substance concentration in conventional STP effluents is expected to be neglectible.

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

Bioaccumulation of Fatty acids, C18-unsatd., dimers, reaction products with fatty acids, C14-18 and C16-18-unsatd. and propylidynemethanol is not expected. Based on the physico/chemical properties such as low water solubility and high potential for adsorption a reduced availability in water is expected. The high molecular weight of the substance significantly reduces the absorption due to steric hindrance to cross biological membranes. BCF/BAF values estimated by QSAR (BCFBAF v3.01) also support the assumption that the bioaccumulation potential of the substance is low (BCF values all well below 2000 L/kg).

 

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