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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Undecylenic acid is produced at above 1000 tons per year and its log Kow is greater than 3 (log Kow=4). Therefore, in the absence of any other information, a fish bioaccumulation study would normally be required by the annex IX of the 1907/2006 EC regulation. However, according to the annex XI of the EC 1907/2006 regulation, a weight of evidence approach can be used to assess if conducting a formal OECD 305 is required:


1) A computer simulation via EPI Suite TM (using an experimental log Kow of 4.0, coming from the Klimisch-1-rated study of GRL 2009, see section 4.7 “Partition coefficient”) resulted in a BCF for undecylenic acid equal to 3.16 L/kg w.w., which is far below the trigger value of BCF = 500 for classification with respect to chronic aquatic toxicity.


2) It is indicated in the toxicokinetic report that, inside of an organism, undecylenic acid should be degradable within the fatty acid metabolism system (see “Toxicokinetics, metabolism and distribution” section).


3) Undecylenic acid is readily biodegradable, which reduces the exposure windows in the aquatic environment and allows ruling out both PBT and vPvB categorisation.


Based on this weight of evidence, we conclude that bioaccumulation of undecylenic acid is unlikely. Thus, the study on bioaccumulation of undecylenic acid can be waived, which is also in accordance to the intention of the REACH regulation to reduce animal use by avoiding unnecessary testing on vertebrates.

Additional information