1,1-diethoxy-3,7-dimethylocta-2,6-diene

Endpoint summary

Description of key information

Short term toxicity to fish:

From ACD (Advanced Chemistry Development)/I-Lab predictive module  (v5.0.0.184) the predicted Median Lethal Concentration (LC50, mg/L) of the test substance 1,1-diethoxy-3,7-dimethylocta-2,6-diene for fish species Pimephales promelas was reported to be 7.2 mg/l on the basis of mortality effects.

The Reliability Index (RI) for the prediction was reported to be0.54( As per model substance have moderate and high reliability ifRI > 0.5).Thus reported RII value indicate it has moderate reliability. And LC50 value indicate that the test substance 1,1-diethoxy-3,7-dimethylocta-2,6-diene considered as harmful to aquatic organisms and thus can be classified in aquatic chronic category 2 as per the CLP classification criteria.

Short term toxicity on aquatic invertebrates

Using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic invertebrates was predicted for 1,1-diethoxy-3,7-dimethylocta-2,6-diene (7492-66-2). EC50 value was estimated to be 12.5 mg/l for Daphnia magna for 48 hrs duration. Based on the value, 1,1-diethoxy-3,7-dimethylocta-2,6-diene (7492-66-2) was considered to be toxic to aquatic invertebrates, hence it can be considered to be classified in chronic category 3 as per the CLP regulations.

Toxicity to aquatic algae and cyanobacteria

Using the OECD QSAR toolbox version 3.3 (2017) with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic algae and cyanobacteria was predicted for target substance 1,1-diethoxy-3,7-dimethylocta-2,6-diene

(CAS no. 7492 -66 -2). EC50 value was estimated to be 4.89 mg/l for Desmodesmus subspicatus for 72 h duration. Based on this value it can be concluded that the substance 1,1 -diethoxy-3,7 -dimethylocta-2,6 -diene is considered to be toxic to aquatic environment and can be considered to be classified in aquatic chronic category 2 as per the CLP classification criteria.

Additional information

Short term toxicity to fish

From ACD (Advanced Chemistry Development)/I-Lab predictive module  (v5.0.0.184) the predicted Median Lethal Concentration (LC50, mg/L) of the test substance 1,1-diethoxy-3,7-dimethylocta-2,6-diene for fish species Pimephales promelas was reported to be 7.2 mg/l on the basis of mortality effects.

The Reliability Index (RI) for the prediction was reported to be0.54( As per model substance have moderate and high reliability ifRI > 0.5).Thus reported RII value indicate it has moderate reliability. And LC50 value indicate that the test substance 1,1-diethoxy-3,7-dimethylocta-2,6-diene considered as harmful to aquatic organisms and thus can be classified in aquatic chronic category 2 as per the CLP classification criteria.

Short term toxicity on aquatic invertebrates

Using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, the short term toxicity on aquatic invertebrates was predicted for 1,1-diethoxy-3,7-dimethylocta-2,6-diene (7492-66-2). EC50 value was estimated to be 12.5 mg/l for Daphnia magna for 48 hrs duration. Based on the value, 1,1-diethoxy-3,7-dimethylocta-2,6-diene (7492-66-2) was considered to be toxic to aquatic invertebrates, hence it can be considered to be classified in chronic category 3 as per the CLP regulations.

Toxicity to aquatic algae and cyanobacteria

Predicted data for the target chemical 1,1-diethoxy-3,7-dimethylocta-2,6-diene(CAS No. 7492-66-2) and various weight of evidence studies for its closest read across substance with logKow as the primary descriptor were reviewed to summarize the following information:

 

Short term toxicity on aquatic algae and cyanobacteria of target chemical1,1-diethoxy-3,7-dimethylocta-2,6-diene(CAS No. 7492-66-2) is predicted using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances (2017).EC50 value was estimated to be 4.89 mg/l for Desmodesmus subspicatus for 72 h duration. Based on this value it can be concluded that the substance 1,1 -diethoxy-3,7 -dimethylocta-2,6 -diene is considered to be toxic to aquatic environment and can be considered to be classified in aquatic chronic category 2 as per the CLP classification criteria.

 

In a weight of evidencestudy from secondary source (HPVIS, 2016) of the read across chemical 11 -methyldodecan-1 -ol (CAS no. 68526 -86 -3),short term toxicity to Pseudokirchnerella subcapitata (green algae) study was carried out for 72 hrs. The study was performed according to OECD Guideline 201 (Alga, Growth Inhibition Test). The study was based on the effects of the read across compound 11 -methyldodecan-1 -ol (CAS no. 68526 -86 -3) on Pseudokirchnerella subcapitata in a static fresh water system under a continuous illumination with a light intensity of 7600 to 7800 Lux., at a temperature of 23.1°C, pH ranges from 6.8 to 7.4 respectively. Pseudokirchnerella subcapitata was used as a test organism. Test chemical concentration used for the study was0,1.5, 3.0, 8.0, 20 and 61mg/L (nominal concentration) and1.5, 2.2, 2.2, 2.5, 3.0 mg/l (measured concentration), respectively. Individual Water Accomodated Fractions (WAFs) were prepared for each test treatment. The test substance was added volumetrically, via a syringe, to 2L of dilution water in a 2L glass bottle. The solution was mixed for 23 hours at a vortex of 8% of the total depth. Mixing temperature was approximately 23 Deg C. After a 1 hour settling/cooling period, the aqueous portions were transferred to the test chambers via the port at the bottom of the mixing vessel and used for testing. Test vessels were 125 ml glass Erlenmeyer flasks that were filled with approximately 60 ml of treatment solution and inoculated with algae. Samples were taken daily for cell counts. Four replicates were prepared for each treatment level. The initial algal concentration was 1.0 x 104cells/ml. All test replicates were placed on a shaker table at 100 oscillations per minute during the study. Biomass was calculated as the area under the growth curve. Based on effect on growth rate of the test organism Pseudokirchnerella subcapitata, the 72 hr NOEC and EC50 value was determined to be 2.2 and 3.2 mg/l and on the basis of effect on biomass, the 72 hr NOEC and EC50 value was determined to be 1.5 and 2.6 mg/l, respectively. Thus, based on the EC50 value, it can be concluded that the substance 11 -methyldodecan-1 -ol can be considered as toxic to aquatic organisms and thus can be considered to be classified in aquatic chronic category 2 as per the CLP classification criteria.

 

Another short term toxicity to algae study was carried out for 72 hrs (OECD SIDS, 2006). The study was based on the effects of the read across compound 7 -methyloctan-1 -ol (CAS no. 27458-94-2) on algae in a static fresh water system. After 72 hours of exposure to 7 -methyloctan-1 -ol, the EC50 value was determined to be ranges from 1.6 to 19.0 mg/l. Thus, based on the EC50 value (1.6 mg/l), it can be concluded that the substance 7 -methyloctan-1 -ol can be considered as toxic to algae at environmentally relevant concentrations and can be considered to be classified in aquatic chronic category 2 as per the CLP classification criteria.

 

Thus, based on the overall reported results for target chemical1,1-diethoxy-3,7-dimethylocta-2,6-diene(OECD QSAR toolbox version 3.3, 2017) and for its read across substance (fromsecondary source HPVIS and OECD SIDS),it can be concluded that the test substance 1,1 -diethoxy-3,7 -dimethylocta-2,6 -diene can be considered as toxic to aquatic environment and can be considered to be classified in aquatic chronic category 2 as per the CLP classification criteria.