trans-menthone

Endpoint summary

Description of key information

Short term toxicity fish:

Based on the prediction done by EPI suite, ECOSAR version 1.11, 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 be 20.973 mg/l for (2R,5S)-5-methyl-2-(propan-2-yl)cyclohexan-1-one (menthone) in 96 hrs. Based on this value it can be concluded that the substance menthone is considered to be toxic to aquatic environment and can be classified in aquatic chronic 3 category as per the criteria mentioned in CLP regulation.

 

Short term toxicity to aquatic invertebrates:

Based on the prediction done by EPI suite, ECOSAR version 1.11, 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 aquatic invertebrates was predicted. On the basis of this program, the LC 50 value for short term toxicity to aquatic invertebrates was predicted to be 12.905 mg/l for CAS name menthone in 48 hrs. Based on this value it can be concluded that the substance is considered to be toxic to aquatic environment and can be classified in aquatic chronic 3 category as per the criteria mentioned in CLP regulation.

Toxicity to aquatic algae and cyanobacteria:

Based on the prediction done using the EPI Suite ECOSAR version 1.10, the short term toxicity on green algae was predicted for test substance menthone (89 -80 -5). On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 13.399 mg/l for green algae for 96 hrs duration. Based on this value, it can be concluded that the test chemical menthone can be considered as toxic to green algae at environmentally relevant concentrations and can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.

 

Toxicity to microorganisms:

Toxicity of menthone on the growth of microorganisms Pseudomonas citronellol is DSM 50332 for 21 days. Analytical grade samples were used for the test. Test performed in 0.5 liter of agar bottle plates by using the pure culture of microorganism providing proper temperature and PH. Culture were inoculated in dark having the mesophilic temperature. Growth inhibition of Pseudomonas citronellolis was observed at 2m M of concentration of menthone for minimum 10 days to 3 weeks. Analytical grade samples were used for the test. Thus after the exposure with chemical no inhibition was observed. On the basis of no growth inhibition of microorganisms Pseudomonas citronellolis due to the menthone for 10 days to 3 weeks, the NOEC was 2mM (308 mg/l).

Additional information

Short term toxicity fish:

Based on the various predicted and experimental data for the target chemical and structurally similar read across chemicals, study have been reviewed to determine toxic nature of menthone (89-80-5) (2R, 5S)-5-methyl-2-(propan-2-yl) cyclohexan-1-one on the growth and other activity of fish. The studies are as mentioned below: 

 

In the first weight of evidence for target chemical menthone toxicity based on the prediction done by EPI suite, ECOSAR version 1.11, 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 be 20.973 mg/l for (2R,5S)-5-methyl-2-(propan-2-yl)cyclohexan-1-one (menthone) in 96 hrs. Based on this value it can be concluded that the substance menthone is considered to be toxic to aquatic environment and can be classified in aquatic chronic 3 category as per the criteria mentioned in CLP regulation.

 

The second predicted report conducted according to aquatic toxicity module i.eACD/Labs I-Lab 2.0; Algorithm Version: v5.0.0.184 the lethal concentration (LC50) of the test substance (2R,5S)-5-methyl- 2-(propan-2-yl)cyclohexan-1-one (menthone) was predicted to be 13 mg/l on fish species Fathead minnow (Pimephales promelas). Based on the LC50 calculation the estimated Reliability Index (RI) of test chemical (2R,5S)-5-methyl-2-(propan-2-yl)cyclohexan-1-one (menthone) predicted to be 0.7(As per model substance have moderate and high reliability ifRI > 0.5).Thus reported RII value indicate it has high reliability. And LC50 value indicate that the test substance (2R,5S)-5-methyl- 2-(propan-2-yl)cyclohexan-1-one (menthone) considered as toxic, harmful to aquatic organisms and thus can be classified in aquatic chronic 3 category as per the CLP criteria.

 

The above data was supported by the experimental report for read across chemical from secondary sources. Aim of this study was to determine the nature of test chemical on the growth of freshwater fish Brachydanio rerio for total exposure of 96 hrs. Chemical was analytically monitored by GC. Test conducted under static system. After incubation period of 96 hrs, slow and inactive swimming behavior and loss of equilibrium (uncontrolled movements) were also observed. Based on the mortality of freshwater fish Brachydanio rerio by the chemical for 96 hrs, the LC50 was determine to be 17.6 mg/l and the LC0 and LC100 was 11.3 mg/l and 26.2 mg/l. Based on the LC50, chemical was consider as toxic and can be consider to not classified as aquatic chronic 3 category as per the CLP classification criteria.

 

Similarly in the fourth experimental weight of evidence study for the read across chemical toxicity was measured. Aim of this study was to determine the nature of chemical on the growth of fish Pimephales promelas for total exposure of 96 hrs. Study was conducted comparable to standard method and in accordance with general accepted scientific standards. Nominal 5 different concentrations in the range of 4.39 to 24.6 mg/l were used and the sample was analytically monetarized by GC method. 0.079 g 30 days old Pimephales promelas (Fathead Minnow) were used. Test conducted under the flow- through system. Observations of fish behavior and body morphology at regular intervals. Affected fish lost schooling behavior, were hypoactive and underreactive to external stimuli. They had increased respiration were darkly colored and lost equilibrium prior to death. Based on the mortality of fishes Pimephales promelas after the exposure of chemical for 96 hrs, the LC50 was determine to be 18.9 mg/l. based on the LC50, chemical was consider as toxic and can be consider to not classified as aquatic chronic 3 category as per the CLP classification criteria.

 

Based on the above overall data for target chemical menthone (89-80-5) and experimental data for structurally and functionally similar read across chemical from secondary source, it was concluded that menthone was toxic and can be consider to be classified as aquatic chronic 3 category as per mention in CLP classification criteria.

 

Short term toxicity to aquatic invertebrates:

Based on the various data for the target chemical study have been reviewed to determine toxic nature of menthone (89-80-5) (2R, 5S)-5-methyl-2-(propan-2-yl) cyclohexan-1-one on the growth and other activity of daphnia magna. The studies are as mentioned below: 

 

In the first weight of evidence study for target chemical menthone toxicity was measured according to the ECOSAR. Based on the prediction done by EPI suite, ECOSAR version 1.11, 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 aquatic invertebrates was predicted. On the basis of this program, the LC 50 value for short term toxicity to aquatic invertebrates was predicted to be 12.905 mg/l for CAS name menthone in 48 hrs. Based on this value it can be concluded that the substance is considered to be toxic to aquatic environment and can be classified in aquatic chronic 3 category as per the criteria mentioned in CLP regulation.

 

First study was supported by another study which was conducted for read across chemical from secondary sources. Short term toxicity study of test chemical on the growth of daphnia magna was carried out for 24 hrs. Various nominal concentration was used in the study 250 mg/l, 125 mg/l, 63 mg/l, 31 mg/l, 15.7 mg/l, 7.8 mg/l, 4.0 mg/l, 2.0 mg/l. Stock solution, 300 mg/l was weighed into water and after treatment with an Ultra-Turrax for 60 sec., stirred on a magnetic stirrer for two hours. In order to avoid uneven distribution of undissolved particles, the solution was kept in movement when preparing the test concentrations. 2 replicates with test substance, and 2 replicates with reference substance, 10 individuals in each test. After the 24 hrs of exposure EC0, EC50 and EC100 value was observed. Based on the immobilization of daphnia magna by the test chemical, the EC0 was 15.7 mg/l, EC50 was 71 mg/l, and EC100 was 125 mg/l. Based on the EC50, chemical was consider as toxic and can be consider as classified in aquatic chronic category 3 as per the CLP classification criteria.

 

Similarly in the third weight of evidence study for another RA chemical supports the toxic nature of chemical. Study was conducted to investigate the effect of chemical when comes in contact with test organism daphnia magna for 48 hrs by using different concentrations of chemical. Test conducted in accordance with OECD guideline 202. Chemical analytically monitored by GC. The test substance was pulverized. A stock solution was prepared to give the desired series of test concentrations. To achieve this 119.9 mg of the test substance were added to 1 liter of dilution water and treated for 1 hour in an ultrasonic bath and afterwards stirred for 24 hours on a magnetic stirrer. Finally undissolved particles of the test substance were removed by filtration using a folded filter of pore size 7 - 12 μm. 3.2, 6.3, 12.5, 25, 50 and 100 mg/l nominal concentrations were used. 20 ml of test medium was added in the vessel which includes 10 neonates. The criterion of adverse effects used in this study was the substance-induced alteration of the normal mobility behavior and the loss of locomotory actions of the neonates, observed at 24 and 48 h. After the exposure of 48 hrs, EC50 was observed at 26.6 mg/l. And the 100 % immobility were observed at 92.35 mg/l. Based on the EC50, chemical was consider as toxic and can be consider to be classified in aquatic chronic category 3 as per the CLP classification criteria.

 

Based on the data from various databases and reports for target menthone (89-80-5) and read across chemicals, menthone concluded as toxic and can be consider to be classified as aquatic chronic 3 category as per mention in CLP classification criteria.

 

Toxicity to aquatic algae and cyanobacteria:

Based on the various predicted and experimental data for the target chemical study have been reviewed to determine toxic nature of menthone (89-80-5) (2R, 5S)-5-methyl-2-(propan-2-yl) cyclohexan-1-one on the growth and other activity of algae. The studies are as mentioned below:

 

In the first weight of evidence study for target chemical menthone toxicity was measured according to the ECOSAR. Based on the prediction done using the EPI Suite ECOSAR version 1.10, the short term toxicity on green algae was predicted for test substance menthone (89 -80 -5). On the basis of effects observed in a static freshwater system, the effect concentration EC50 value for the substance is estimated to be 13.399 mg/l for green algae for 96 hrs duration. Based on this value, it can be concluded that the test chemical menthone can be considered as toxic to green algae at environmentally relevant concentrations and can be considered to be classified in aquatic chronic category 3 as per the CLP classification criteria.

 

First study was supported by another study which was conducted for read across chemical from secondary sources. Study of toxicity of test chemical on the growth of green algae for 72 hrs was carried out. Test performed in accordance with OECD Guideline 201 (Alga, Growth Inhibition Test) under static system. After the exposure of chemical with the green algae the EC50 and NOEC value was measured. Based on the growth rate inhibition of algae the EC50 and NOEC was >2.5 and 2.5mg/l. But on the basis of AUG the EC5O and the NOEC was >70 mg/l. Thus based on the EC50 (>70 mg/l) value by considering AUG, chemical was concluded as toxic and can be consider to be classified as chronic 3 category.

 

Similar results was obtain for another read across chemical from secondary source. Short term toxicity study of test chemical on the growth of Scenedesmus subspicatus (Algae) was carried out for 72 hours. The study was performed according the standard OECD guideline 201. Test conducted under the static system. Control and test material is used in the test. Based on the growth inhibition of algae due to the test chemical for 72 hrs. The NOEC was 5 mg/l, LOEC was 10mg/l and the ErC50 was 16.2 mg/l. Based on the EC50, chemical was consider as toxic and can be consider to be classified in aquatic chronic category 3 as per the CLP classification criteria.

 

Based on the data from various databases and secondary sources for target menthone (89-80-5) and read across chemicals, menthone was toxic and can be consider as classified as aquatic chronic 3 category as per mention in CLP classification criteria.

 

Toxicity to microorganisms:

Toxicity of menthone on the growth of microorganisms Pseudomonas citronellol is DSM 50332 for 21 days. Analytical grade samples were used for the test. Test performed in 0.5 liter of agar bottle plates by using the pure culture of microorganism providing proper temperature and PH. Culture were inoculated in dark having the mesophilic temperature. Growth inhibition of Pseudomonas citronellolis was observed at 2m M of concentration of menthone for minimum 10 days to 3 weeks. Analytical grade samples were used for the test. Thus after the exposure with chemical no inhibition was observed. On the basis of no growth inhibition of microorganisms Pseudomonas citronellolis due to the menthone for 10 days to 3 weeks, the NOEC was 2mM (308 mg/l).