Fatty acids, C8-10, C8-10-alkyl esters

Endpoint summary

Additional information

There are no data available on the biodegradation of Fatty acids, C8-10, C8-10 alkyl esters (CAS 129677-93-6). 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 a structurally related substance was conducted.

In accordance with Article 13 (1) of Regulation (EC) No 1907/2006, "information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI are met.” In particular for human toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, which includes the use of information from structurally related substances (grouping or read-across).

Having regard to the general rules for grouping of substances and read-across approach laid down in Annex XI, Item 1.5, of Regulation (EC) No 1907/2006 whereby substances may be predicted as similar provided that their physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity.

The source substanceTetradecanoic acid, tetradecyl ester (CAS 3234-85-3)is representative to evaluate the biodegradation of the target substanceFatty acids, C8-10, C8-10 alkyl esters.Tetradecanoic acid, tetradecyl esteris characterized by a longer fatty acid chain length (C14 linear) and a longer fatty alcohol chain length (C14 linear) and can be used for read-across as a worst case approach since the chain length of the fatty alcohol and the fatty acid are the determining factor for biodegradation.A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

Fatty acids, C8-10, C8-10 alkyl esters is characterised by a low vapour pressure (0.000115 - 0.0152 Pa at 20 °C, SPARC (v4.6)), a low water solubility (4.6 µg/L at 20 °C, pH 6.3) and a log Koc indicating a potential for adsorption to soil and sediment particles (log Koc 3.90 - 4.94, MCI method, KOCWIN v2.00). Based on the result from the selected source substance, the target substance is readily biodegradable (67% after 28 d (OECD 301C). This is supported by reliable (Q)SAR data for the constituents of the target substance. Thus, it is expected that an extensive elimination of the substance in sewage treatment plants will occur. In the case insoluble chemicals enter a standard Sewage Treatment Plant (STP), they will be extensively removed in the primary settling tank and fat trap and thus, only limited amounts will get in contact with activated sludge organisms, according to the Guidance on information requirements and chemical safety assessment, Chapter R.7b (ECHA, 2014). As a result of the adsorption potential of the substance (log Koc 3.90 - 4.94, MCI method, KOCWIN v2.00) a removal from the water column to a significant degree by adsorption to sewage sludge can be expected (Guidance on information requirements and chemical safety assessment, Chapter R.7b, (ECHA, 2014). In conclusion, the concentration of the substance in conventional STP effluents is presumably marginal. Abiotic degradation via hydrolysis is considered as not relevant for the substance. Calculations using HYDROWIN v2.00 predict half-lives > 1 year at pH 7 for the main components of the substance (Szymoszek, 2014). Moreover, the substance is not volatile (VP 0.000115 - 0.0152 Pa at 20 °C) and thus evaporation to the air and subsequent transport through the atmosphere to other environmental compartments is not likely. However, if the substance is released into air, the substance is susceptible to indirect photodegradation in air by OH-radicals as half-lives of less than 24 hours were calculated for the main components of the substance (Szymoszek, 2014).

Based on the low water solubility and metabolism via enzymatic hydrolysis of the substance a relevant uptake and bioaccumulation in aquatic organisms is not expected. The substance will be hydrolysed and the cleavage products can be further metabolised. In conclusion, bioaccumulation and biomagnification through the food chain of the substance is not expected. This is supported by (Q)SAR calculations using BCFBAF v3.01 (Arnot-Gobas, including biotransformation, upper trophic). All constituents of the UVCB substance are within the applicability domain of the model and clearly indicate a low potential for bioaccumulation with BCF values of 14.07 - 207.8 L/kg whole body ww and BAF values of 230.8 - 314 L/kg whole body ww. Please refer to IUCLID Section 5.3 for a detailed overview on bioaccumulation of the substance.

As it can be seen in the data matrix of the analogue justification in IUCLID Section 13, all reliable data from the target and the source substance support the read-across by showing a consistent pattern of results.