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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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BCF QSAR Fish (range; all constituents - block method approach): 5.75 – 16.98 ± 0.70-1.68 L/Kg ww, BCF base-line model v.02.09; OASIS Catalogic v5.11.17, Firmenich SA 2016

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Additional information

In accordance with REACH Regulation (EC) No. 1907/2006 Annex XI, section 1.2 justification for not performing a bioaccumulation study includes expert assessment: The components of the UVCB substance are not bioaccumulative despite having components with Log Kow > 4.0 since branched esters are expected to be rapidly metabolised and/or excreted by mammals. Specifically, branched esters are metabolized by the same metabolic processes to that of dietary fats and are extensively metabolized by carboxylesterase enzymes that are ubiquitous across vertebrate and invertebrate species. Specific enzymatic activity explains the discrepancy between model predictions and actual bioconcentration potential is the rapid metabolism of this class of chemistry by fish. Models that do not account for metabolism over predict bioaccumulation potential in fish. The applicant adapts the information requirement through (i) (Q)SAR assessment utilising the block-method and (ii) providing evidence of substance metabolism and elimination within the literature, for a weight-of-evidence approach to the endpoint which indicates no reasonable foreseen bioaccumulation potential.

 

OASIS Catalogic v5.11.17 - BCF base-line model v.02.09, Bioconcentration factor (BCF), July 2015

Estimated Log BCF = 0.78 – 1.23 (all constituents)

The range of constituents BCF was as follows for each block assigned by expert judgement, structure and/or predicted physicochemical properties – of the selected representative structures:

C10-branched (n ≤2): Estimated Log BCF = 0.78 - 0.83 ; BCF = 5.75 – 7.41 ± 0.92 L/kg wet-wt

C11-branched (n >2): Estimated Log BCF = 0.90 – 1.02 ; BCF = 7.94 – 10.47 ± 1.37 L/kg wet-wt

C11-branched (n ≤2): Estimated Log BCF = 0.88 – 1.01 ; BCF = 7.59 – 10.23 ± 1.29 L/kg wet-wt

C12-branched (n >2): Estimated Log BCF = 1.07 – 1.19 ; BCF = 11.75 – 15.49 ± 1.64 L/kg wet-wt

C12-branched (n ≤2): Estimated Log BCF = 1.03 – 1.23 ; BCF = 9.55 – 16.22 ± 1.68 L/kg wet-wt