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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Significant accumulation in organisms is not to be expected.

Key value for chemical safety assessment

Additional information

In ECHA's Guidance Document on information requirements and chemical safety assessment Chapter R.7c (R.7.10.3.4, p. 23ff) and Chapter R.11(R.11.1.3.2, p. 27f) it is laid out that several substance properties (e.g. logPow, molecular size of substance) can be combined in a weight of evidence approach to evaluate the substance's bioaccumulation potential.

The evaluation of physico-chemical substance properties resulted in a logPow of 2 for Pigment Orange 67 which indicates that the substance is expected to be rather hydrophobic with a low potential for bioaccumulation. Other supporting indicators are the molecular length (4.4 nm) and molecular diameter (4.6 nm) of Pigment Orange 67. Both values exceed their established threshold limits (threshold molecular length of 4.3 nm; threshold molecular diameter of 1.7 nm) which results either in the substance disturbing the entire interior structure of the lipid bilayer of cell membranes or in the failure of the molecule to cross cell membranes because it is simply too bulky to do so. Both factors result in a reduced BCF of the substance.

Therefore, it can be expected that Pigment Orange 67 has a low bioaccumulation potential.