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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Alchisor TAL 111 is an alkenes C10 -C11, hydroformylation product, low boiling and can be characterised as a UVCB substance. As defined in the ‘Read-Across Justification Document’ section 13, data provided for the analogue substance Alchisor TAL 123 and the Alchisor TAL 111 consitutent category substances, Category 3 hydrocarbon solvents, are representative of Alchisor TAL 111 and suitable for assessment purposes. Study data for each analogue/constituent category has been evaluated and considered together. The most relevant and reliable study result from across the analogue/constituent categories has been identified and used to address the endpoint in question.  The data requirement for bioaccumulation is being waived.

Key value for chemical safety assessment

Additional information

Alchisor TAL 111 is an alkenes C10 -C11, hydroformylation product, low boiling and can be characterised as a UVCB substance. As defined in the ‘Read-Across Justification Document’ section 13, data provided for the analogue substance Alchisor TAL 123 and the Alchisor TAL 111 consitutent category substances, Category 3 hydrocarbon solvents, are representative of Alchisor TAL 111 and suitable for assessment purposes. Study data for each analogue/constituent category has been evaluated and considered together. The most relevant and reliable study result from across the analogue/constituent categories has been identified and used to address the endpoint in question.The data requirement for bioconcentration is being waived as follows:

C9-C14 aliphatics (2-25% aromatics)

Standard tests for the bioaccumulation endpoint are intended for single substances. Bioaccumulation testing has not been designed for C9-C14 aliphatics (2-25% aromatics) which are UVCB hydrocarbons. However, this endpoint has been calculated for representative hydrocarbon structures using the BCFWIN v2.16 model within EPISuite 3.12 or EUSES as input to the hydrocarbon block method incorporated into the PETRORISK model. The PETRORISK derivations are provided in Section 13 of the CSR. In addition, supporting information reported in CONCAWE’s approach (Lampi et al., 2010), which is also included in Section 13 of the CSR, provides evidence of over-estimation when BCF’s are predicted through modelling approaches. PETRORISK model predictions for hydrocarbons ranged from 45.5 to 21,710.

Supporting information found in the CONCAWE report presents model predictions based on bioconcentration potential in fish and reliable experimental data for algae and Daphnia species. Two types of model prediction are presented; the first is a regression output from the BCFBAF model of EPISuite (US EPA, 2009) in which fish biotransformation of hydrocarbons is not explicitly taken into account. The second prediction uses the BCF model developed by Arnot and Gobas (2003) which includes lipid content predictions as recommended in ECHA Guidance (Chapter R.7C, ECHA, 2008). The report states that there is marked influence of fish biotransformation exerted on the predicted BCFs derived using the two types of modelled results for all hydrocarbon blocks (including, paraffins, iso-parafins (or branched paraffins) and mono-aromatics). The BAF predictions were judged to be inappropriate for hydrocarbons since metabolism in the gut (which is effectively assumed in food chain model calculations) is ignored. The decision to exclude BAF model predictions was supported by the experimental dietary BMF data demonstrating the critical role of gut metabolism in limiting biomagnification of hydrocarbons via the diet. For example, for mono-aromatics C12 to C17, all regression model predictions are above the B (bioaccumulation (B) criterion in PBT assessment) criterion of 2000. When biotransformation is incorporated into the model, none of the predictions are above 2000. Experimentally-derived dietary BCF values which are typically more conservative than aqueous BCF values are below the B criterion for all tested structures (C9 to C16). Aqueous BCFs for all other mono-aromatic hydrocarbons are below 2000. It is concluded by CONCAWE that based on available data, mono-aromatic hydrocarbons are neither bioaccumulative nor very bioaccumulative. Similar assessments for paraffins and branched (or iso-) paraffins concluded that C13 and C14 paraffins and C12-C16 branched paraffins may be bioaccumulative but not very bioaccumulative.

Conclusion

As a consequence of bioaccumulation studies being waived as unsuitable, as forC9-C14 aliphatics (2-25% aromatics), no reliable measured bioconcentration information is required for constituent categories of Alchisor TAL 111. The data requirement for bioconcentration/bioaccumulation is being waived for Alchisor TAL 111 on the basis that the studies are waived for its constituent category substances.

 

References:

Lampi et al. 2010. An Evaluation of the Persistence, Bioaccumulation and Toxicity of PetroleumHydrocarbonsPrepared for CONCAWE March 2010.

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