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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information




According to ECHA Guidance Chapter R.11 Version 3.0 (June 2017), the Bioaccumulation criterion is unlikely to be triggered for substances with a log Kow higher than 10.



Indeed, for highly hydrophobic substances, like the registered substance with a log Kow > 6, experimentally derived BCF values tend to decrease with increasing log Kow. Several explanations of this breakdown of linerarity can be given. Conceptual explanations of this non-linearity mainly refer to either biotransformation, reduced membrane permeation kinetics or reduced biotic lipid solubility for large molecules. A low bioavailability and uptake of these substances in the organism will thus occur. Other factors comprise experimental artefacts, such as equilibrium not being reached, reduced bioavailability due to sorption to organic matter in the aqueous phase, and analytical errors. In addition, as the registered substance is readily biodegradable, it is quite likely that, in an experimental study (via food or water), a low bioavailability, a metabolic hydrolysis and a reduced membrane uptake rate will thus occur. The uptake by oral route is more critical (dietary fedding study). In this case, the substance is likely to be broken in the gut and any bioaccumulation would be due to oral consumption of the narcotic by-products and the weak acid.


To confirm that no bioaccumulation is expected for the registered substance considering the high hydrophobic properties and rapid metabolisation (ester hydrolysis) of the substance, QSAR prediction using Arnot-Gobas methodology was performed, including biotransformation rate estimates. The estimated BCF values were all comprised between 0.94 and 9.42 L/kg. The registered substance is not bioaccumulable according to CLP (BCF < 500) and PBT criteria (BCF < 2000). However, based on restrictions on the applicability domain, these predictions are considered rather as qualitative than quantitative.


Also, the registered substance presents no toxicity for mammals. The "No Observed Adverse Effect Level", NOAEL, was determined at the highest tested dose in the sub-acute toxicity study and sub-chronic oral toxicity studies. This observation confirm the limit absorption and therefore the limited bioaccumulation of the registered substance.



Additional information

According to the key biodegradation study, no transformation product was detected at the end of the 28-day test period. Therefore, the evaluation of the bioaccumulation potentiel of the transformation product(s) is not relevant.

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