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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Regarding all available data significant accumulation according to PBT criteria can be excluded. 

Key value for chemical safety assessment

Additional information

The bioaccumulation potential of the substance was tested in a bioconcentration test (Gakushuin University, Institute of Ecotoxicology 1979). Japanese carp (Cyprinus carpio) were exposed to the substance for 60 days. The determined bioconcentration factors were 49.3 - 437.1 for the 0.1 ppm concentration and 24.3 - 340 for the 0.01 ppm concentration. Therefore, the test item is not bioaccumulative according to PBT-criteria. Despite the use of acetone as solvent the test is regarded as acceptable since the test concentrations are both below the water solubility of 1 mg/L.

The results are supported by the molecular weight (685.0315 g/mol) of the test item and the maximum diameter of the molecule that was calculated using CATALOGIC v5.11.5. It resulted in an average maximum diameter (Dmaxaver) of 1.69 nm. According to the guidance on information requirements and chemical safety assessment Chapter R.11 - PBT Assessment - another parameter that directly reflect the molecular size of a substance is the average maximum diameter (Dmaxaver). Very bulky molecules will less easily pass the cell membranes. This results in a reduced BCF of the substance. From a diverse set of chemicals it appeared that for compounds with a Dmaxaverlarger than 1.7 nm the BCF value was less than 5000 L/kg. It can be assumed combining the maximum diameter of 1.69 nm and the high molecular size of the test item that the test item will not easily pass the cell membranes, the uptake is reduced and bioaccumulation will not occur. Moreover, the logPow of 4.2 shows that the test substance is not bioaccumulative according to PBT criteria either.

Additionally, four different calculations were conducted to support these results:

1.) US EPA T.E.S.T v4.0.1 using the consensus method resulted in a BCF of 27.14.

2.) US EPA EPISuite v4.10 (BCF BAF v3.01) revealed a BCF of 121 L/kg wet-wt using the measured logPow of 4.2.

3.) CATALOGIC v5.11.5 (BCF base-line model v2.05) resulted in a BCF of 60.22 with all mitigating factors applied. Even though the structural domain was correct with only 43.18% (56.82% unknown) the results support the overall conclusion in a weight of evidence.

4.) VEGA BCF model (CAESAR) version 2.1.13 resulted in a predicted BCF of 3.31 L/kg (logBCF = 0.52). Likewise CATALOGIC the test substance was out of domain. Nevertheless, the results can be used in the weight of evidence to give an indication if the test substance has a bioaccumulative potential.