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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

Alchisor TAL 123 can be characterised according to three constituents: Hydrocarbons C11-C14, n-alkanes, isoalkanes, cyclics, aromatics (2-25%), undecan-1-ol and dodecan-1-ol.  In a protective approach the most sensitive study result from across the three constituents will be identified and used to address the hazard endpoint in question. As a consequence of bioaccumulation studies being either unsuitable, as for Hydrocarbons C11-C14, n-alkanes, isoalkanes, cyclics, aromatics (2-25%), or technically unfeasible, as for undecan-1-ol and dodecan-1-ol, no reliable measured bioconcentration information is available for constituents of Alchisor TAL 123. The data requirement for bioaccumulation is being waived.

Key value for chemical safety assessment

Additional information

Alchisor TAL 123 can be characterised according to three constituents: Hydrocarbons C11-C14, n-alkanes, isoalkanes, cyclics, aromatics (2-25%), undecan-1-ol and dodecan-1-ol (see the Read-Across Justification Document in Section 13). In a protective approach the most sensitive study result from across the three constituents will be identified and used to address the hazard endpoint in question. As a consequence of bioaccumulation studies being either unsuitable, as for Hydrocarbons C11-C14, n-alkanes, isoalkanes, cyclics, aromatics (2-25%), or technically unfeasible, as for undecan-1-ol and dodecan-1-ol, no reliable measured bioconcentration information is available for constituents of Alchisor TAL 123. The data requirement for bioconcentration is being waived as follows:

Hydrocarbons C11-C14, n-alkanes, isoalkanes, cyclics, aromatics (2-25%)

Standard tests for the bioaccumulation endpoint are intended for single substances. Bioaccumulation testing has not been designed for Hydrocarbons C11-C14, n-alkanes, isoalkanes, cyclics, aromatics (2-25%) 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 BCFs 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-paraffins (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.

Undecan-1-ol

 In accordance with REACH Annex XI, the study is waived on the basis that bioaccumulation in fish would be confounded by the technical difficulties of maintaining the test alcohols in solution; as was demonstrated in the long-term studies of effects in invertebrates (see Section 6.1.1.2 in the CSR), severe difficulties were encountered in conducting the study as biodegradation of structurally analogous substances in the test system was almost complete within the 24 h test media renewal period. There is no requirement in REACH to conduct any secondary poisoning assessment in view of the lack of toxic effects in mammals.

Dodecan-1-ol

In accordance with REACH Annex XI, the study is waived on the basis that bioaccumulation in fish would be confounded by the technical difficulties of maintaining the test alcohols in solution; as was demonstrated in the long-term studies of effects in invertebrates (see Section 6.1.1.2 in the CSR), severe difficulties were encountered in conducting the study as biodegradation of structurally analogous substances in the test system was almost complete within the 24 h test media renewal period. There is no requirement in REACH to conduct any secondary poisoning assessment in view of the lack of toxic effects in mammals.

Conclusion

As a consequence of bioaccumulation studies being waived as unsuitable, as for Hydrocarbons C11-C14, n-alkanes, isoalkanes, cyclics, aromatics (2-25%), or technically unfeasible, as for undecan-1-ol and dodecan-1-ol, no reliable measured bioconcentration information is required for constituents of Alchisor TAL 123. The data requirement for bioconcentration/bioaccumulation is being waived for Alchisor TAL 123 on the basis that the studies are waived for all its constituents.

 

References:

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