3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one

Endpoint summary

Description of key information

Short term toxicity to fish:

Based on the prediction done by EPI suite, ECOSAR version 1.1, on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program, the LC 50 value for short term toxicity to fish was predicted.On the basis of this program, the LC 50 value for short term toxicity to fish was predicted to be1.428mg/l for test materialin 96 hrs.Based on this value it can be concluded that the substance is considered to be toxic to aquatic environment and can be classified as aquatic acute 2 as per the criteria mentioned in CLP regulation.

Short term toxicity to aquatic invertebrate:

Aim of this study was to assess the short term toxicity of test material to aquatic invertebrates daphnia magna. Study was performed according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) in a static system for the total exposure period of 48 hrs.

 The stock solution 10.0 g/l was prepared by dissolving colourless liquid in acetone. The test solutions of required concentrations were prepared by mixing the stock solution of the test substance in reconstituted water.0.5, 1.0 , 2.0 , 4.0 , 8.0 mg/lconcentrations were used in the study. Effects on immobilisation were observed for 48 hours. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. The median effective concentration (EC50) for the test substance , in Daphnia magna was determined to be 4.7 mg/L on the basis of mobility inhibition effects in a 48 hour study. Based on the EC50 value, substance is likely to be hazardous to aquatic invertebrate and can be classified as aquatic acute 2 category as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria:

Aim of this study was to evaluate the nature of chemical test chemical when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). Test was conducted according to the OECD guideline 201.The stock solution 10.0 g/l was prepared by dissolving dense liquid in acetone. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.0.5 , 1.3 , 3.2 , 8.0 , 20.0 mg/lconcentrations were used. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. Effect on the growth of algae was determine after an exposure period of 72 hrs.

The median effective concentration (EC50) for the test substance , in algae was determined to be >20 mg/L on the basis of growth rate inhibition effects in a 72 hour study. Based on the EC50 value, the classification of test material can not be concluded as it was not possible to test higher sample concentrations due to low sample solubility and no mortalities were observed till the last limit of solubility.

Toxicity to microorganisms:

1. The Minimum Inhibitory Concentration (MIC) value of test chemical on the fungi  Colletotrichum musae DAR 24962 was determine to be 894.195 mg/L.

2. Based on the antimicrobial effect of test chemical on the growth of Bacillus subtilis after the exposure of chemical for 2-5 days, the MIC was observed at 100 mg/l.

Thus based on the above studies, MIC ranges from 100 mg/l to 894.195 mg/l after the exposure of microorganisms with the test chemical for 2-10 days.

Additional information

Short term toxicity to fish:

The toxicity of test material was evaluated for fish using a predicted study and to support the prediction data , study from secondary source of structurally similar read across substance was also used.

Based on the prediction done by EPI suite, ECOSAR version 1.1, on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program, the LC 50 value for short term toxicity to fish was predicted.On the basis of this program, the LC 50 value for short term toxicity to fish was predicted to be1.428mg/l for test materialin 96 hrs.Based on this value it can be concluded that the substance is considered to be toxic to aquatic environment and can be classified as aquatic acute 2 as per the criteria mentioned in CLP regulation.

The above prediction was further supported by data from secondary source, experimental study for test chemical was conducted according to guideline 203. Rainbow Trout (average length, 5.8 cm), were exposed to a series of 5 test concentrations of 0, 7.8, 10.9, 15.3, 21.4, or 30 mg/L dispersed in Polysorbate 80 (10 mg/L) for 96 hours at 17.1 °C. Control fish were exposed to polysorbate 80 (10 mg/L). Fish were observed twice daily for mortality and symptoms. pH values and water temperature were monitored after substance addition at 24 hour intervals. Dissolved oxygen was measured at the beginning of the experiment and at 96 hours. The LC50 value for the given test material is 10.9 mg/L.Based on the above effect concentration it can be concluded that test material is toxic to fish and can be classified as aquatic acute 2.

According to another study from secondary source , as per the guideline 203, Rainbow Trout (average length, 6-8 cm), were exposed to a series of 2 test concentrations of 0, 5, or 10 mg/L of4-(2,6,6-trimethylcyclohex-1-en-1-yl)but-3-en-2-onefor 96 hours at 16+/-1°C.During experiment the LC0 was determined to be 5 mg/L while LC100 as 10 mg/L. Thus LC50 value for the given test material was considered to be between 5mg/L and 10 mg/L.Based on the above effect concentration it can be concluded that test material is toxic to fish and can be classified as aquatic acute 2.

In a data from peer reviewed handbook it was observed that,short term toxicity of test material was evaluated for Leuciscus idus fish for 96 h . The minimum leathel effect concentration (LC50) was observed to be 6.8 mg/l. Based on the above effect concentrations it can be concluded that test material is toxic to fish and can be classified as aquatic acute 2.

Short term toxicity to aquatic invertebrate:

Aim of this study was to assess the short term toxicity of test material to aquatic invertebrates daphnia magna. Study was performed according to the OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test) in a static system for the total exposure period of 48 hrs.

 The stock solution 10.0 g/l was prepared by dissolving colourless liquid in acetone. The test solutions of required concentrations were prepared by mixing the stock solution of the test substance in reconstituted water.0.5, 1.0 , 2.0 , 4.0 , 8.0 mg/lconcentrations were used in the study. Effects on immobilisation were observed for 48 hours. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. The median effective concentration (EC50) for the test substance , in Daphnia magna was determined to be 4.7 mg/L on the basis of mobility inhibition effects in a 48 hour study. Based on the EC50 value, substance is likely to be hazardous to aquatic invertebrate and can be classified as aquatic acute 2 category as per the CLP classification criteria.

Toxicity to aquatic algae and cyanobacteria:

Aim of this study was to evaluate the nature of chemical test chemical when comes in contact with the test organism Desmodesmus subspicatus (previous name: Scenedesmus subspicatus). Test was conducted according to the OECD guideline 201.The stock solution 10.0 g/l was prepared by dissolving dense liquid in acetone. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.0.5 , 1.3 , 3.2 , 8.0 , 20.0 mg/lconcentrations were used. With the test substance one positive control Potassium dichromate (K2Cr2O7) was also run simultaneously. After the exposure of chemical, effect concentration EC50 was calculated using nonlinear regression by the software Prism 4.0. Effect on the growth of algae was determine after an exposure period of 72 hrs.

The median effective concentration (EC50) for the test substance , in algae was determined to be >20 mg/L on the basis of growth rate inhibition effects in a 72 hour study. Based on the EC50 value, the classification of test material can not be concluded as it was not possible to test higher sample concentrations due to low sample solubility and no mortalities were observed till the last limit of solubility.

Toxicity to microorganisms:

Based on the various experimental data for the test chemical and structually and functionally similar read across chemicals, study have been reviewed to determine the toxic nature of test chemical on the growth of microorganisms. The studies are as mentioned below:  

The effects of test chemical on the growth of Colletotrichum musae on agar medium were evaluated. Test was performed on the agar medium. Agar plugs (5.5-mm diam.) were picked up from the 3-day-old cultures of decay fungi using the bottom end of a sterilized Pasteur pipet and then transferred onto the centers of new PDA media, in 9-cm plastic Petri dishes. The Petri dishes were then inverted and 7-cm Whatman No. 1 filter papers were attached onto the inner surface of their lids. Ethanol, the first tested volatile in this experiment, was impregnated into the filter paper with varying volumes from 0.1 to 1.0 mL/dish in the 4°C room. Immediately after the impregnation, the Petri dishes were sealed by wrapping them with plastic film and incubated for 10 days at 25 °C. Experiments were repeated two times with four replications for each experiment. The minimum concentration of ethanol (expressed as mmol/dish) required to give complete control or the minimum inhibitory concentration (MIC) for each microorganism was determined. The MIC of ethanol for target decay microorganism was used as the initial level to identify the MIC of other tested volatiles. If the MIC level of ethanol used for other volatiles failed to stop the growth of pathogen, the level was increased until the MIC was found. However, if the volume of 1.5 mL/dish still failed to stop the growth of pathogen, the compound was considered ineffective as a vapor to stop the growth of pathogens. When the tested compounds had the same effect as the MIC of ethanol, the concentration was decreased until the MIC of the compound for each microorganism was determined. All the unit concentrations of MIC were then expressed as mmol/dish. After the incubation of 10 days, the Minimum Inhibitory Concentration (MIC) value of test chemical on the fungi, Colletotrichum musae DAR 24962 was determine to be 894.195 mg/L.

 

First study was supported by the second experimental study. Aim of this study was to evaluate the effect of test chemical on the growth of Bacillus subtilis and other fungi. The antimicrobial activity of test compounds against various bacteria and fungi was examined by the broth dilution method. Solution of the test compound was added to 2-day-old cultures of the microorganisms. After 2-5 days of incubation, growth of the microorganisms was checked. Minimal inhibitory concentrations (MICs) were measured by two fold serial broth dilution. Based on the antimicrobial effect of test chemical on the growth of Bacillus subtilis after the exposure of chemical for 2-5 days, the MIC was observed at 100 mg/l.

 

Thus based on the above studies, MIC ranges from 100 mg/l to 894.195 mg/l after the exposure of microorganisms with the test chemical for 2-10 days.