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Short-term toxicity to fish

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Reference
Endpoint:
short-term toxicity to fish
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
Data is from computational model developed by USEPA
Reference:
Composition 0
Qualifier:
according to
Guideline:
other: Modeling database
Principles of method if other than guideline:
ECOSAR estimates log Kow values using the US EPA's KOWWIN Program for aquatic toxicity.Toxicity of a chemical was measured on the basis of similarity of structure to chemicals for which the aquatic toxicity has been previously measured by structure-activity relationships (SARs) program based upon the octanol /water partition coefficient (Kow). Data from ECOSAR class,neutral organics was used.The estimation methods in EPI Suite™ have been developed by government, academic, and private sector researchers over many years and represent some of the best techniques currently available. The intended application domain of EPI Suite is organic chemicals, and inorganic as well as organometallic chemicals generally can be considered outside the domain.
GLP compliance:
no
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material (IUPAC name): (2R,5S)-5-methyl-2-(propan-2-yl)cyclohexan-1-one- Common name: Menthone - Molecular formula: C10H18O- Molecular weight: 154.2512 g/mol- Smiles notation: C1([C@@H](CC[C@@H](C1)C)C(C)C)=O- InChl: 1S/C10H18O/c1-7(2)9-5-4-8(3)6-10(9)11/h7-9H,4-6H2,1-3H3- Substance type: Organic- Physical state: Liquid
Analytical monitoring:
not specified
Vehicle:
not specified
Test organisms (species):
other: Fish
Test type:
not specified
Water media type:
not specified
Total exposure duration:
96 h
Reference substance (positive control):
not specified
Key result
Duration:
96 h
Dose descriptor:
LC50
Effect conc.:
20.973 mg/L
Nominal / measured:
estimated
Conc. based on:
not specified
Basis for effect:
mortality
Remarks on result:
other: Neutral Organics
Validity criteria fulfilled:
not specified
Conclusions:
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.
Executive summary:

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.

Description of key information

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.

Key value for chemical safety assessment

LC50 for freshwater fish:
20.973 mg/L

Additional information

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.