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Ecotoxicological information

Endpoint summary

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Additional information

Short-term aquatic toxicity data are available for each of the three freshwater trophic levels (fish, daphnia and algae). 

 

An experimental study is available for daphnia which gave a 48h EC50 of 2.4mg/L.

 

In the absence of experimental data, the use of QSAR predicted values has been used to assess toxicity to fish and algae. Two well-established software tools have been used, ECOSAR v1.11 and OECD QSAR Toolbox v3.4.0.17. The predicted 96 hour Fish LC50 values range from 2.3 -7.6mg/L and the algae EC50 values from 4.3 -11.9 mg/L.The prediction result using the ECOSAR Aldehydes (mono) SAR has been chosen as the key value for both fish and algae since it is the most conservative value. Furthermore, the applicability of the Aldehydes (mono) SAR class to the prediction of aquatic toxicity for the registration substance is supported by a comparison of predicted and measured values for the daphnia endpoint (2.3 and 2.4 mg/L respectively – see QPRF documents for prediction of fish 96h LC50 and algae EC50 using ECOSAR v1.11).

 

The registration substance is a mono-constituent substance. All QSAR results reported are for the main constituent, 2,6-dimethylhept-5 –enal. Impurities present in the registration substance were also considered. Details are provided in the supporting QPRF documents for the ECOSAR v.11 predictions and IUCLID endpoint records. In summary, ECOSAR v1.11 assigns all impurities to the neutral organic ECOSAR class and predicts lower toxicity than for the main constituent. For example, the predicted Green Algae 96-hr EC50 values for the impurities range from 11.9 to 39.7 mg/L (Neutral Organic SAR). In contrast, the main constituent has a predicted EC50 of 4.3 mg/L (Aldehyde Mono SAR). Similarly for fish, the predicted 96-hr LC50 values for the impurities range from of 18.5 to 91.3 mg/L (Neutral Organic SAR) while the predicted value for the main constituent is 2.3mg/L (Aldehyde Mono SAR). Therefore, an assessment of the aquatic toxicity of the registration substance based only on the major constituent is considered justifiable and worst-case.

 

Toxicity to microorganisms was assessed as part of a standardised ready biodegradation test. The substance did not inhibit degradation of the positive control at a test concentration of 100mg/L. Thus this concentration can be considered the NOEC for toxicity to STP microorganisms.