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Environmental fate & pathways

Endpoint summary

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Description of key information

The substance hydrolyses under neutral and alkaline conditions, is readily biodegradable, not bioaccumulating and has strong adsorption characteristics (logKoc > 6).

Additional information

Given the use and physico-chemical properties of alkyl ketene dimers, photodegradation is not seen as a relevant sink. Alkyl ketene dimers are expected to hydrolyse readily under neutral and alkaline conditions in the environment and are assumed to be stable to hydrolysis at acidic pH values.


 


All alkyl ketene dimers are classified as readily biodegradable based on the ready biodegradability test result of 2-Oxetanone, 3-C12-16-alkyl-4-C13-17-alkylidene and the biodegradation mechanism of ketones.


Calculated Koc values indicate that AKD will strongly adsorb to soil and sediment.


 


At log Kow values between 4 and 5, log BCF increases linearly with log Kow. This linear relationship is the basis for the B screening criterion of log Kow > 4.5. At very high log Kow (>6), a decreasing relationship between the two parameters is observed. The very high log Kow value (> 11) therefore suggests that AKD should be considered as not bioaccumulatingAdditionally direct and indirect exposure of the aquatic compartment is limited, the bioavailability of the substance is very low, and no specific uptake mechanism apart from lipophilic partitioning is known or suspected. In conclusion, AKD does not fulfil the bioaccumulation criteria and should not be considered as bioaccumulating (B) or very bioaccumulatinge (vB).