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Environmental fate & pathways

Endpoint summary

Administrative data

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Additional information

There are no data available on the biodegradation oftetradecyl stearate (CAS 17661-50-6). 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 structurally related substances 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 target substance is a UVCB substance. It is characterized by a linear C16 and C18 fatty acid esterified with a linear C14 alcohol. The two source substances selected for the assessment of biodegradation are structurally very similar to the target substance. 9-Octadecenoic acid (Z)-, C12-15-alkyl esters (CAS 68412-06-6) is an ester of an unsaturated C18 fatty acid esterified with a C12-C15 linear alcohol.Docosyl docosanoate (CAS 17671-27-1) is characterised as an ester of mainly linear C22 fatty acid esterified with a linear C22 alcohol. Using both source substances allows for interpolation to the target substance. They cover the upper and lower end of C-chains of the fatty acid and the alcohol.A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

Tetradecyl stearate (CAS 17661-50-6) is characterized by a low vapour pressure (VP < 0.0001 Pa at 20 °C, SPARC (v4.6)), a low water solubility (0.5-1 µg/L at 20 °C, pH 6) and a high log Koc indicating a high adsorption potential to soil and sediment particles (log Koc > 5, MCI method, KOCWIN v2.00). Based on the result from the selected source substances, the target substance is readily biodegradable (75.3% after 28 d (OECD 301C) and 89.9% after 29 d (OECD 301B). 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 high adsorption potential of the substance (log Koc > 5, 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 for the main components of the substance (Müller, 2015). Moreover, the substance is not volatile (VP < 0.0001 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 tetradecyl stearate 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 (Müller, 2015).

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. Tetradecyl stearate will be hydrolysed and the cleavage products can be further metabolized. In conclusion, bioaccumulation and biomagnification through the food chain of the substance is not expected. This is supported by a low calculated BCF value of 0.89 - 0.90 L/kg ww (BCFBAF v3.01, Arnot-Gobas, including biotransformation, upper trophic). Please refer to IUCLID Section 5.3 for a detailed overview on bioaccumulation of tetradecyl stearate.

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.