monoesters of C16 and C18 (branched and linear) fatty acids with decan-1-ol

Endpoint summary

Additional information

There is only limited data available on the environmental fate of Monoesters of C16 and C18 (branched and linear) fatty acids with decan-1 -ol.

Therefore, QSAR calculations were performed on decyl isooctadecanoate (CAS 84605-08-3) to calculate log Koc values in order to fulfill the standard information requirements laid down in Reach Regulation (EC) No 1907/2006, Annex VIII.

Monoesters of C16 and C18 (branched and linear) fatty acids with decan-1-ol is a long-chain aliphatic ester and a UVCB substance, characterized by low water solubility (< 0.16 mg/L, OECD 105), and based on calculations on decyl isooctadecanoate (CAS 84605-08-3), a low estimated vapour pressure (< 0.0001 Pa, MPBPWIN v1.43), a high estimated log Kow (> 10.0, QSAR) and a high estimated log Koc (> 5.0, KOCWIN v4.11).

Based on experimental results from a standard biodegradation study, the substance is readily biodegradable according to OECD criteria (OECD 301 B). Based on the available data, abiotic degradation via hydrolysis and evaporation into the atmospheric compartment are not relevant removal pathways. The substance is expected to partition to organic particles in sediment and soil as well as to dissolved particulate matter in the water phase. 

According to the Guidance on information requirements and chemical safety assessment, Chapter R.7b, readily biodegradable substances can be expected to undergo rapid and ultimate degradation in most environments, including biological Sewage Treatment Plants (STPs) (ECHA, 2017). Due to ready biodegradability and high potential for adsorption, the substance can be effectively removed in conventional STPs by biodegradation and sorption to biomass. Furthermore, the Guidance also states that once insoluble chemicals enter a standard STP, they will be extensively removed in the primary settling tank and fat trap and thus, only limited amounts will come into contact with activated sludge microorganisms. Therefore, only negligible concentrations of the substance are likely to be released into the environment through conventional STPs, if at all. Whatever fraction is still released into the aquatic environment will undergo extensive biodegradation and will preferentially distribute into the sediment compartment through sorption to organic matter, leading to a rapid reduction of the bioavailability of the substance in the water column. Thus, the relevant route of exposure and uptake in aquatic organisms is expected to predominantly occur by ingestion of particle bound substance, but the bioavailability of the substance is presumably very low based on the physico-chemical properties of the substance (i.e. strong binding). Experimental data for bioaccumulation is not available and the estimated log Kow is high (> 10), which may be indicative of a potential for bioaccumulation. However, based on current knowledge, a calculated log Kow of 10 or above is taken as an indicator of reduced bioconcentration, according to the Guidance on Information Requirements and Chemical Safety Assessment, Chapter R.7c: Endpoint specific guidance (ECHA, 2017).