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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

The test substance does not significantly accumulate inorganisms.

Key value for chemical safety assessment

Additional information

The pKa for the test substance was calculated to be 3.79 using SPARC (v4.6). This value indicates that the test substance will exist primarily as an anion in the environment (pH 4 to 9).The partitioning coefficient for the charged molecule at pH 7 was estimated to be below three (logD = 1.9). In accordance with Annex IX column 2 of Regulation (EC) No. 1907/2006, the study on bioaccumulation does not need to be conducted if the substance has a low potential for bioaccumulation (e.g. logKow < 3).

Additionally, it is known that charged molecules do not pass cell membranes as easy as their neutral counterpart. Thus, leading to a decreased potential of bioaccumulation.

However, four QSAR calculations were conducted to investigate the potential of bioaccumulation more in detail. All calculations show clearly a low potential for bioaccumulation, even though, some of the calculations use a calculated (overestimated) logPow from the uncharged molecule.

US EPA T.E.S.T v4.0.1 using the consensus method resulted in a BCF of 23.63.

US EPA EPISuite v4.10 (BCF BAF v3.01) revealed a BCF of 10 L/kg wet-wt including the fact that the test substance is charged.

CATALOGIC v5.11.5 (BCF base-line model v2.05) resulted in a BCF of 56.7 with all mitigating factors applied. The test substance is within the applicability domain of the model. The structural domain was correct with 95 % (unknown 5 %).

VEGA BCF model (CAESAR) version 2.1.8 resulted in a predicted BCF of 123 L/kg. However the test substance could be out of the model applicability domain. Nevertheless, the results can be used in the weight of evidence to give an indication if the test substance has a bioaccumulative potential.

In overall conclusion, these results indicate that the test item has only a low potential to accumulate in aquatic organisms and clearly failing the PBT cut off of 2000.

Therefore, a test on bioaccumulation is not provided.