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Short-term toxicity to fish:

Predicted model data and experimental study result for the test chemical 3,7-dimethylocta-2,6-dienenitrile (CAS No. 5146-66-7) with respective read across were reviewed to summarize the following information:

In key study the 96 hrs aquatic toxicity study was predicted to assess toxic effects of the test compound 3,7-dimethylocta-2,6-dienenitrile (CAS no. 5146-66-7) and the result were predicted (SSS QSAR Prediction model, 2016). The study was based on the effects of the test compound on Danio rerio fish in a static fresh water system. The predicted data suggests the lethal concentration (LC50) for the test compound was estimated to be 6.618789196 mg/l on the basis of mortality effect.

Whereas supporting model which is based on the QSAR prediction done using the EPI Suite ECOSAR version 1.10 (EPI Suite, 2016), the 96 hours LC50 was estimated to be 5.917 mg/l on fish for substance 3,7-dimethylocta-2,6-dienenitrile (CAS no. 5146-66-7) with mortality effects.

Based on above predicted value from SSS QSAR and ECOSAR, it can be concluded that the substance can be considered as toxic to fish and thus as per the CLP classification guidance the chemical classified in aquatic chronic category 2.

Above predicted lethal concentrations supported by experimental study for read across chemical Phoxim (Cas no. 14816-18-3) which is indicates that In acute toxic study for various sensitive aquatic species of aquatic environment the 410 chemicals was tested including test chemical 4-Ethoxy-7-phenyl-3,5-dioxa-6-aza-4-phosphaoct-6-ene-8-nitrile 4-sulfide to assess the toxic effects.

During study the 0.01, 0.110,100,1000,10000 mg/l test concentrations was used with test condition 44 mg/L CaCO3 hardness, 12 deg.C test temp. and 7.4 pH in static fresh water.

According to study the lethal concentration (LC50) of test substance 4-Ethoxy-7-phenyl-3,5-dioxa-6-aza-4-phosphaoct-6-ene-8-nitrile 4-sulfide on fish species Pimephales promelas (Fathead Minnow) for 96 hrs. on the basis of mortality effect was observed to be 2.9 mg/l with 95% confidence limit 2.26-3.721 mg/l.

Thus, based on above all mentioned lethal concentration values, it can be concluded that the target chemical 3,7-dimethylocta-2,6-dienenitrile (CAS No. 5146-66-7) can be considered as toxic to fish and thus classified in aquatic chronic category 2 as per the CLP criteria.

Short term toxicity to aquatic invertebrates

Various predicted studies and read across study for the3,7-dimethylocta-2,6-dienenitrilewere reviewed to summarize the following information: 

48 hrs aquatic toxicity study (EPI suite, ECOSAR version 1.1, 2016) were conducted to assess toxic effects of3,7-dimethylocta-2,6-dienenitrile (CAS no5146-66-7)and the results were predicted. The study was based on the effects of the test compound on the Daphnia magna in a static fresh water system. The predicted data suggests the lethal concentration (LC50) for the3,7-dimethylocta-2,6-dienenitrile (CAS no5146-66-7)was estimated to be 3.847mg/L.

 

Using similar experimental conditions, 48 hrs aquatic toxicity studies (SSS QSAR prediction model, 2016) were conducted to assess toxic effects of3,7-dimethylocta-2,6-dienenitrile (CAS no5146-66-7)and the results were predicted. The study was based on the effects of the test compound on the Daphnia magna in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the3,7-dimethylocta-2,6-dienenitrile (CAS no5146-66-7)was estimated to be 2.28 mg/Lon the basis of intoxication.

 

The acute toxicity test of 3,7-dimethylocta-2,6-dienenitrile was performed on daphnia according to OECD guideline 202 in closed vessel. The exposure duration of chemical was 24 and 48 hr. The 24-h EC50 value was determined to be 26 mg/L and 48-h EC50 found to be 7.66 mg/L. The NOEC value for 48h was determined to be 3.13mg/l.

As based on the above predicted data and read across study, it can be considered that 3,7-dimethylocta-2,6-dienenitrile (CAS no 5146-66-7) is likely to be toxic to aquatic invertebrates can be classified in aquatic chronic 2 categories as per CLP regulation

Toxicity to aquatic algae and cyanobacteria

Various predicted data for the target chemical Citralva (CAS No. 5146-66-7) and the study of its read across substance were reviewed to summarize the following information:

72 hrs aquatic toxicity study was predicted to assess toxic effects of the test compound Citralva (CAS no. 5146 -66 -7) and the result were predicted (SSS QSAR Prediction model, 2016). The study was based on the effects of the test compound on Pseudokirchnerella subcapitata in a static fresh water system. The predicted data suggests the effective concentration (EC50) for the test compound Citralva (CAS no. 5146 -66 -7) was estimated to be 3.1739 mg/l on the basis of growth rate.

 

Based on the QSAR prediction done using the EPI Suite ECOSAR version 1.10 (EPI Suite, 2016), the 96 hours EC50 was estimated to be 5.014 mg/l on green algae for substance Citralva with growth inhibition effects.

The short term toxicity study to algae test was performed according to OECD guideline 201 in closed vessels (CLASSIFICATION AND LABELLING OF DANGEROUS SUBSTANCES Recommended form to be used for the proposed classification and labelling of a dangerous substance under Directive 67/548/EEC, January 2007). The test performed onDesmodesmus subspicatusCHODAT SAG 86.81strain, with dose concentration of 3.7 to 100 mg/L which were weighed separately (differential loading) and exposure duration was 72-h. Due to technical reasons for the concentrations 1.23 mg/l to 0.015 mg/l an eluate was created and used for the study. The 72-h EbC50 and ErC50 value was found to be 5.92 and 6.35 respectively when exposed to algae by chemical 3,7-dimethylocta-2,6-dienenitrile.

Short term toxicity toSelenastrum capricornutum(green algae) study was carried out for 96 hrs (Danisco US Inc, 8EHQ-0309-17438A, March 6, 2009). The study was based on the effects of the test compound onSelenastrum capricornutumin a static fresh water system. The 72 hrs IC50 and NOEC values onSelenastrum capricornutumwas determined to be 3.99 mg/l and < 1 mg/l, respectively.

Based on the overall reported results for target and read across substance, it can be concluded that the substance Citralva can be considered as toxic to aquatic organisms and thus can be classified as aquatic chronic category 2 as per the CLP criteria.