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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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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.  

Key value for chemical safety assessment

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 Kow< 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 Kow≥ 4.39) exceeds the criterion log Kowof 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 4, DT50= 61 minutes at 15oC and DT50= 37 minutes at 25oC; at pH 7, DT50= 44 minutes at 15oC and DT50= 22 minutes at 25oC; at pH 9, DT50= 4.9 minutes at 15oC and DT50= 2.3 minutes at 25oC). 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 also states that “in most cases hydrolysis products are more hydrophilic and as a consequence will have a lower potential for bioaccumulation” (Ibid.). Therefore, bioaccumulation testing of the substance in aquatic species is not indicated.