Lauric acid, ester with hydroxypropanediyl diacetate

Endpoint summary

Additional information

There are no data available on the biodegradation of Lauric acid ester with hydroxypropanediyl diacetate (CAS 30899-62-8). 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 as a triester of glycerol esterified with acetic acid and lauric acid. A structurally very similar substance was selected as source substance to cover the data requirements. The source substance Glycerides, C8-21 and C8-21-unsatd. mono- and di-, acetates (CAS 97593-30-1) is a multi-constituent substance described as a triester of glycerol with acetic acid and lauric acid in a slightly different composition compared to the target substance. Thus, both substances are considered to be structurally similar and the information on the source substance can be used to predict the biodegradation of the target substance. A detailed analogue approach justification is provided in the technical dossier (see IUCLID Section 13).

Lauric acid ester with hydroxypropanediyl diacetate (CAS 30899-62-8) is characterized by a low vapour pressure (VP <0.0001 Pa at 20 °C (QSAR, SPARC v4.6)), a low water solubility (<0.15 mg/L at 20 °C and pH=6.2 - 6.6) and a high log Koc indicating a high adsorption potential to soil and sediment particles (log Koc ≥ 3.71, MCI method, KOCWIN v2.00). Based on the result from the selected source substance, the target substance is readily biodegradable (83% after 28 d (OECD 301F). This result was confirmed by reliable QSAR calculations for the target substance itself. 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, 2016). As a result of the high adsorption potential of the substance (log Koc ≥ 3.71, 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, 2016). 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 of 23.14 - 192.8 d at pH7 for the main components of the substance (Müller, 2016). 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 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 (Müller, 2016).

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 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 0.913 - 12.3 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 Lauric acid ester with hydroxypropanediyl diacetate.

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.