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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

The bioaccumulation potential is expected to be low

Key value for chemical safety assessment

Additional information

Experimental data investigating the bioaccumulation potential of Glyceryl undecylenate (CAS 123759-97-7) are not available. The log Pow values of the main substance components (log Pow: 3.04 to > 10) indicate a bioaccumulation potential. However due to the expected environmental behaviour and metabolism of the substance bioaccumulation is not expected (in accordance with REACh Regulation (EC) No. 1907/2006, Annex XI General rules for adaptation of the standard testing regime set out in Annexes VII to X, 1.2, to cover the data requirements of Regulation (EC) No. 1907/2006, Annex IX). The substance is considered readily biodegradable and is insoluble in water (water solubility < 1 mg/L). 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). The guidance document states furthermore 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 get in contact with activated sludge organisms (ECHA, 2014). Therefore, after passing through conventional STPs, only low concentrations of these substances are likely to be (if at all) released into the environment.
If released to the water the substance will tend to bind to sediment and other particulate organic matter due to their hydrophobicity and relatively high adsorption potential (log Koc: 1.2 – 4.32). The actual dissolved fraction available to fish via water is assumed to be low. Thus, the most relevant exposure route for aquatic organisms such as fish will be via particle-bound food ingestion or contact with suspended solids. If the substance is ingested by organisms a fast metabolisation is expected. Carboxylesterases are a group of ubiquitous and low substrate specific enzymes, involved in the metabolism of ester compounds in both vertebrate and invertebrate species, including fish (Barron et al., 1999). Glycerides are the predominant lipid class in the diet of both marine and freshwater fish. Once ingested, they will be hydrolysed into fatty acids and glycerol by a specific group of carboxylesterase (CaE) enzymes (lipases) as reported in different fish species (Tocher, 2003). According to the Guidance on information requirements and chemical safety assessment, Chapter R.7c (ECHA, 2014), even though ready biodegradability does not per se preclude bioaccumulation potential, generally (depending on exposure and uptake rates) ready biodegradable substances are likely to be rapidly metabolised, and therefore, concentrations stored in aquatic organisms will tend to be low.
Estimated bioconcentration (BCF) and bioaccumulation (BAF) values were calculated for the substance using the BCFBAF v3.01 program (Estimation Programs Interface Suite™ for Microsoft® Windows v 4.11., US EPA), assuming biotransformation (Arnot-Gobas method). The estimated BCF values for the main substance components ranged from 3.49 – 6.78 L/kg.

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