2-Octen-1-ylsuccinic anhydride, mixture of cis and trans

Bioaccumulation: aquatic / sediment

Link to relevant study record(s)

Reference

Endpoint:

bioaccumulation in aquatic species: fish

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance has a low potential for bioaccumulation based on log Kow <=3

other:

Description of key information

Testing for bioaccumulation in aquatic species was waived.  The substance has a low potential for bioaccumulation, and direct or indirect exposure of the aquatic compartment is unlikely. Therefore, bioaccumulation testing of the substance in aquatic species is not indicated, in accordance with Regulation (EC) No.1907/2006, Annex IX, Column 2.  

Additional information

According to Regulation (EC) No.1907/2006, Annex IX, Column 2, bioaccumulation testing in aquatic species, preferably fish, need not be conducted if the substance has a low potential for bioaccumulation (for instance a log K_ow< 3), or if direct or indirect exposure of the aquatic compartment is unlikely. Although the experimentally-determined octanol-water partitioning coefficient for the substance (log K_ow≥ 4.68) exceeds the criterion log K_owof 3, the substance nevertheless exhibits a low potential for bioaccumulation.  The substance has been shown to undergo rapid hydrolysis at environmentally relevant pH and temperature conditions (i.e., at pH 7, DT₅₀= 8.3 minutes at 15^oC and DT₅₀= 4 minutes at 25^oC). Each of these hydrolysis half-life values is substantially below the threshold half-life of 12 hours, below which “it can be assumed that the rate of hydrolysis is greater than that for uptake by exposed organisms” (Chapter R.7.c, “Endpoint-specific guidance”,Guidance on information requirements and chemical safety assessment, ECHA, May 2008, Section R.7.10.3.4, p. 24). The ECHA guidance subsequently states that “in most cases hydrolysis products are more hydrophilic and as a consequence will have a lower potential for bioaccumulation” (Ibid.). This statement is consistent with the predicted partition coefficient for octenyl succinic acid, the hydrolysis product of the substance (log K_ow= 3.42, KOWWIN v1.68, EPI Suite), which falls below the screening criterion for “not bioaccumulative” and “not very bioaccumulative” (i.e., log K_ow≤ 4.5) in the PBT/vPvB evaluation (Chapter R.11, “PBT Assessment”,Guidance on information requirements and chemical safety assessment, version 1.1, ECHA, November 2012, Section R.11.1.2.2, p. 30). The substance is readily biodegradable, and therefore the hydrolysis products are subsequently biodegraded and do not exhibit the potential for bioaccumulation. Therefore, bioaccumulation testing of the substance in aquatic species is not indicated.