Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

1,2,3-propanetriyl triisooctadecanoate (CAS 26942-95-0) is not readily biodegradable according to OECD criteria (40.2 – 42.3% in 28 d). The substance is furthermore characterised by low water solubility (WS <0.05 mg/L), low vapour pressure (< 0.0001 Pa) and a high log Koc (13.96). Hydrolysis is not expected to be a relevant degradation pathway for the substance as indicated by QSAR calculations performed with the HYDROWIN v2.00 program resulting in estimated half-lives in water of 1.51 year (at pH 7) and 55.14 days (at pH 8).

The Guidance on information requirements and chemical safety assessment, Chapter R.7b (ECHA, 2012) states that once 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. As a result of the high adsorption potential of the substance (log Koc: 13.96, 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, 2012). In conclusion, the concentration of the substance in conventional STP effluents is presumably very low. Abiotic degradation is not expected due to the high estimated half-lives of >1 year (HYDROWIN v2.00).

The volatilization potential of the substance is negligible, based on a vapour pressure < 0.0001 Pa at 20°C. Nevertheless, if released into the atmosphere, the substance is expected to be rapidly photodegraded based on the estimated half-lives in air of 5.3 hours (AOPWIN 1.92 program). Based on the above information, accumulation in air, subsequent transportation through the atmosphere and deposition into other environmental compartments is not anticipated.

Considering the expected relatively high adsorption potential, low volatilization potential and low water solubility of the substance, a distribution to soil and sediment is likely if the substance is released to the environment.

Based on the low water solubility and metabolization via enzymatic hydrolysis a relevant uptake and bioaccumulation in aquatic organisms is not expected. Enzymatic breakdown will initially lead to the free fatty acid and glycerol. From literature it is well known, that these hydrolysis products will be metabolised and excreted in fish effectively (Tocher, 2003). This is supported by calculated BCF values ranging from 0.89-56.7 L/kg (BCFBAF v3.01, Arnot-Gobas, including biotransformation, upper trophic). Please refer to IUCLID Section 5.3.1 for a detailed overview on bioaccumulation of the substance.

A detailed reference list is provided in the technical dossier (see IUCLID, section 13) and within the CSR.