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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

No experimental data on bioaccumulation are available for the substance. The constituents of the UVCB are mainly surfactants (acido-basic and oxido –reductive reactions of the terminal-OH may occur). Hence , its adsorption and bioaccumulation potential cannot be predicted by their Kow portioning.  In addition, the only QSAR method (BCFWIN) is not reliable for substances with long alkyl chain. It can be expected that the substance has a moderate to high bioaccumulation potential . Testing of single constituents or a realistic worst case representative of the constituents would be necessary to determine the actual bioaccumulation potential.

Key value for chemical safety assessment

Additional information

No experimental data on aquatic bioaccumulation are available. The study to determine the partition coefficient (log Kow) gives data ranging from 2.9 to 7.7, indicating a high bioaccumulation potential. This study was performed by QSAR estimation as the chemical is a insoluble UVCB, very difficult to test.

The substance contains about 34% of octadecanol (C18 alcohol) with a log Log Kow =7.7.

The alkyl chain length has the highest impact on the log Kow value.

A quantitative estimation of the bio concentration factor (BCF) for fish can be performed according to the parabolic equation given in the guidance on information requirements and chemical safety assessment (Chapter R7c) for substances having a log Kow>6:

Parabolic equation: Log BCFfish= -0.20 x(log Kow)² +2.74 x log Kow-4.72

Log BCFfish=-0.20 x (7.7)² + 2.74x7.7-4.72

Log BCFfish=4.52

BCFfish=33113L/kg

A BCF was estimated by BCF BAF: Log BCF from regression-based method = 3.176 (BCF = 1501 L/kg wet-wt)

Log BCF Arnot-Gobas method (upper trophic) = 2.299 (BCF = 199.2)

Log BAF Arnot-Gobas method (upper trophic) = 3.850 (BAF = 7074)

Log Kow used: 7.72 (estimated)

However, this method delivers many underestimations of BCFs.

Hence, QSAR-method is not reliable for estimating the bioaccumulation potential of the substance. The BCFBAF and equation lead to very different results. Considering the chemical is readily biodegradable and its different components (degradation products: alcohols and glucose), we can expect a low bioaccumulation potential. So, we do not propose further testing on bioaccumulation.