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Toxicity to terrestrial arthropods

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Reference
Endpoint:
toxicity to terrestrial arthropods: short-term
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data is from peer reviewed journal
Justification for type of information:
Data is from peer reviewed journal
Reference:
Composition 0
Qualifier:
according to
Guideline:
other: Refer below principle
Principles of method if other than guideline:
Study was conducted to determine the effect of test chemical on the larvicidal activity of Ochlerotatus caspius.
GLP compliance:
not specified
Application method:
contact
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material (IUPAC Name): 2-Isopropyl-5-methylphenol- Common name: Thymol- Molecular formula: C10H14O- Molecular weight: 150.2196 g/mol- Smiles notation: c1(c(cc(C)cc1)O)C(C)C- InChI: 1S/C10H14O/c1-7(2)9-5-4-8(3)6-10(9)11/h4-7,11H,1-3H3- Substance type: Organic- Physical state: Solid- Chemical purchase from Sigma-Aldrich Co
Analytical monitoring:
yes
Vehicle:
yes
Remarks:
DMSO
Details on preparation and application of test substrate:
Details on test solutionsPREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)- Chemical name of vehicle (organic solvent, emulsifier or dispersant): DMSO- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 1 ML
Test organisms (species):
other: Ochlerotatus caspius
Animal group:
Diptera (mosquitoe)
Details on test organisms:
- Laboratory culture: Larvae collected from salty rocky pools, from the shore of Enfe, Batroun Co., Lebanon
Study type:
laboratory study
Total exposure duration:
48 h
Post exposure observation period:
24 and 48hrs
Test temperature:
26°C
Details on test conditions:
Details on test conditionsTEST SYSTEM- Test vessel: Larval trays- Material, size, headspace, fill volume: Larval trays (9-3/4 × 7-3/4 in)- No. of organisms per vessel: 15- No. of vessels per concentration (replicates): 3- No. of vessels per control (replicates): 3- No. of vessels per vehicle control (replicates): 3OTHER TEST CONDITIONS- Photoperiod: 12 hours light and 12 hours darkEFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Mortality were observed in the interval of 24 hrs.
Nominal and measured concentrations:
Testes at 4 different concentrations (5-30 ul/200 ml sea water)
Reference substance (positive control):
not specified
Key result
Duration:
48 h
Dose descriptor:
LC50
Effect conc.:
33.31 other: mg/l
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: 95 % CI was 27.51 – 37.56 mg/l
Duration:
24 h
Dose descriptor:
LC50
Effect conc.:
33.65 other: Mg/l
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: 95 % CI was 27.83 – 38.37 mg/l
Duration:
48 h
Dose descriptor:
other: LC90
Effect conc.:
47.91 other: mg/l
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: 95 % CI was 42.96-57.61 mg/l
Duration:
24 h
Dose descriptor:
other: LC90
Effect conc.:
50.85 other: mg/l
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: 95 % CI was 45.18-61.38 mg/l
Details on results:
Larvae were consider dead if they did not move when they were slightly stimulated with a wooden stick.
Reported statistics and error estimates:
The lethal concentrations for 50% and 90% of the mortality were calculated using the Probit SPSS Analysis.
Validity criteria fulfilled:
not specified
Conclusions:
Test conducted for 48 hrs for determining the effect of chemical on the larvicidal activity of Ochlerotatus caspius (Mosquito). Based on the mortality of test organism for 48 hrs and 24hrs, the LC50 was determine to be 33.31 and 33.65 mg/l. and the LC90 was determine at 47.91 mg/l at 48 hrs and 50.85 mg/l after 24 hrs.
Executive summary:

Study was conducted to determine the effect of test chemical on the larvicidal activity ofOchlerotatus caspius. Chemical was analytically monitorized by GC. 1 ml DMSO use as a solvent in which 200 ml sea water were added. Testes at 4 different concentrations (5-30 ul/200 ml sea water). Larvae collected from salty rocky pools, from the shore of Enfe, Batroun Co., Lebanon.Mortality were observed in the interval of 24 hrs. In which 3 replicates were used and in each larval tray 15 test organism added. Test conducted for 48 hrs for determining the effect of chemical on the larvicidal activity of Ochlerotatus caspius (Mosquito). Based on the mortality of test organism for 48 hrs and 24hrs, the LC50 was determine to be 33.31 and 33.65 mg/l. and the LC90 was determine at 47.91 mg/l at 48 hrs and 50.85 mg/l after 24 hrs.

Description of key information

Study was conducted to determine the effect of test chemical on the larvicidal activity of Ochlerotatus caspius. Chemical was analytically monitorized by GC. 1 ml DMSO use as a solvent in which 200 ml sea water were added. Testes at 4 different concentrations (5-30 ul/200 ml sea water). Larvae collected from salty rocky pools, from the shore of Enfe, Batroun Co., Lebanon.Mortality were observed in the interval of 24 hrs. In which 3 replicates were used and in each larval tray 15 test organism added. Test conducted for 48 hrs for determining the effect of chemical on the larvicidal activity of Ochlerotatus caspius (Mosquito). Based on the mortality of test organism for 48 hrs and 24hrs, the LC50 was determine to be 33.31 and 33.65 mg/l. and the LC90 was determine at 47.91 mg/l at 48 hrs and 50.85 mg/l after 24 hrs.

Key value for chemical safety assessment

Additional information

Toxicity to terrestrial arthropods:

Summarized result for the toxicity of chemical on the growth of terrestrial arthropods are as follows:

 

In the first key study for target chemical from peer reviewed journal toxicity was measured. Study was conducted to determine the effect of test chemical on the larvicidal activity of Ochlerotatus caspius. Chemical was analytically monitored by GC. 1 ml DMSO use as a solvent in which 200 ml sea water were added. Testes at 4 different concentrations (5-30 ul/200 ml sea water). Larvae collected from salty rocky pools, from the shore of Enfe, Batroun Co., Lebanon. Mortality were observed in the interval of 24 hrs. In which 3 replicates were used and in each larval tray 15 test organism added. Test conducted for 48 hrs for determining the effect of chemical on the larvicidal activity of Ochlerotatus caspius (Mosquito). Based on the mortality of test organism for 48 hrs and 24hrs, the LC50 was determine to be 33.31 and 33.65 mg/l. and the LC90 was determine at 47.91 mg/l at 48 hrs and 50.85 mg/l after 24 hrs.

 

Similarly the second study was also supports the nature of chemical from secondary source 2018. Study was conducted to determine the toxicity of chemical on Aedes aegypti. Test performed for 24 hrs on the 3-4 ins larval Aedes aegypti (Yellow Fever Mosquito). Based on the mortality of test organism Aedes aegypti (Yellow Fever Mosquito), by the chemical Thymol (5-Methyl-2-(1-methylethyl)phenol) exposure for 24 hrs, the LC50 was determine to be 79 mg/l. As the chemical was readily biodegradable in water thus consider as nontoxic and not classified as per the CLP classification criteria.