Registration Dossier
Registration Dossier
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EC number: 203-427-2 | CAS number: 106-72-9
Toxicity to aquatic algae and cyanobacteria
Administrative data
Link to relevant study record(s)
Description of key information
In the absence of experimental data, the use of predicted values has been used to assess toxicity to aquatic algae. Two well-established software tools have been used, ECOSAR v1.11 and OECD QSAR Toolbox v3.4.0.17. The ECOSAR programme attributes 2,6-dimethylhept-5-enal to the chemical class of Aldehydes (mono). However, for this QSAR Class the Supporting Information in the Ecosar Help states that “The green algae 96-h SAR for Neutral Organics may be used to estimate toxicity for Aldehydes (mono) with log Kow values less than 6.4 and molecular weights less than 1000.” Presumably this is because the Aldehyde (Mono) SAR is based only on 3 data points and that the predicted values are similar to that obtained from the neutral organic SAR. Both ECOSAR models, Aldehydes (mono) and Neutral Organics, have been used. Two predictions were also performed using the QSAR Toolbox; one using a category formed from the aquatic toxicity databases publicly available in the Toolbox and one using a category formed from Givaudans' proprietary database. The predicted algae EC50 values were 4.3, 9.3, 7.7 and 11.9 mg/L respectively. The prediction results are considered reliable according to OECD principles. The prediction models are scientifically valid and 2,6-dimethylhept-5-enal falls within their applicability domain. Furthermore, the models are independent from each other (e.g. based on different training sets). Thus, the agreement among the predictions increases the confidence in the reliability of the predictions. Taking a conservative approach, the lowest value of 4.3 mg/L has been chosen as the key value for chemical safety assessment.
Key value for chemical safety assessment
- EC50 for freshwater algae:
- 4.3 mg/L
Additional information
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