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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Predicted BCF for DIBK is 130 L/kg (BCFBAF v3.00)
Predicted BCF for other components/impurities of the substance are 50 and 23 L/kg.

Key value for chemical safety assessment

BCF (aquatic species):
130 L/kg ww

Additional information

The fish BCF values for DIBK and its two reported impurities were estimated using two accepted QSAR methods:

1. U.S. EPA BCFBAFWIN v3.00 software

2. OASIS CATALOGIC v05.10.06 running Base-line BCF model v01.02

The BCFBAFWIN software predicted fish BCF values within a factor of 4 for four structural analogs (ketones) having log Pow values which bracketed those of DIBK and its impurities. The Base-line BCF software consistently predicted BCF values which were significanlty lower than measured values. However, this software predicts two possible transformation steps which could mitigate bioconcentration by facilitating excretion of the substances from fish:

1) Phase I reduction of ketone groups to corresponding alcohols

2) Phase II glucoronidation at the alcohol groups

Using the estimations of BCFBAFWIN as the preferred values, the predicted BCF for DIBK is 130 L/kg (BCFBAF v3.00)

Predicted BCF for other components/impurities of the substance are 50 and 23 L/kg.