Indole

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

QSAR

Principles of method if other than guideline:

QSAR

GLP compliance:

no

Key result

Duration:

96 h

Dose descriptor:

EC50

Effect conc.:

ca. 37.3 mg/L

Nominal / measured:

not specified

Conc. based on:

not specified

Basis for effect:

not specified

Details on results:

Based on the Neutral Organics QSAR equation for the prediction of algae 96-h EC50, ECOSAR predicted a EC50 equal to 37.30 mg/L.

Validity criteria fulfilled:

no

Conclusions:

Prediction based on the Neutral Organics equation is provided to allow the assessment of predicted excess toxicity compared to baseline (non-polar) narcosis. Since at least one class of excess toxicity is identified for the target, the prediction based on the Neutral Organics equation could under-estimate potential toxicity of the target. Based on the Neutral Organics QSAR equation for the prediction of algae 96-h EC50, ECOSAR predicted a EC50 equal to 37.30 mg/L. The target Indole is included in the applicability domain of the model since LogKow and MW values of the target are below the defined thresholds and the MW of Indole is included in the MW range of the training set. However, the prediction was assessed as borderline reliable due to possible under-estimation of potential toxicity.

Executive summary:

Prediction based on the Neutral Organics equation is provided to allow the assessment of predicted excess toxicity compared to baseline (non-polar) narcosis. Since at least one class of excess toxicity is identified for the target, the prediction based on the Neutral Organics equation could under-estimate potential toxicity of the target. Based on the Neutral Organics QSAR equation for the prediction of algae 96-h EC50, ECOSAR predicted a EC50 equal to 37.30 mg/L. The target Indole is included in the applicability domain of the model since LogKow and MW values of the target are below the defined thresholds and the MW of Indole is included in the MW range of the training set. However, the prediction was assessed as borderline reliable due to possible under-estimation of potential toxicity.

It should not be categorised as Aquatic toxic acut (limit 1 mg/l).

It is a readily biodegradable substance. Its log kow is 2.24. It should not be categorised as aquatic toxic chronic.

Description of key information

Prediction based on the Neutral Organics equation is provided to allow the assessment of predicted excess toxicity compared to baseline (non-polar) narcosis. Since at least one class of excess toxicity is identified for the target, the prediction based on the Neutral Organics equation could under-estimate potential toxicity of the target. Based on the Neutral Organics QSAR equation for the prediction of algae 96-h EC50, ECOSAR predicted a EC50 equal to 37.30 mg/L. The target Indole is included in the applicability domain of the model since LogKow and MW values of the target are below the defined thresholds and the MW of Indole is included in the MW range of the training set. However, the prediction was assessed as borderline reliable due to possible under-estimation of potential toxicity.

Key value for chemical safety assessment

EC50 for freshwater algae:

37.3 mg/L