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Toxicity to terrestrial arthropods

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toxicity to bees: acute oral
Acute toxicity via contact was also assessed.
Type of information:
experimental study
Adequacy of study:
key study
Study period:
24 August 1987 - 30 August 1987
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
equivalent or similar to guideline
other: Working Document D3 of the United Kingdom Pesticide Safety Precautions Scheme
not specified
Principles of method if other than guideline:
Test done in accordance with the regulations: EPA FIFRA 71-2
GLP compliance:
Application method:
other: Both oral and contact
Analytical monitoring:
Details on sampling:
Not applicable
Details on preparation and application of test substrate:
- Method of test material application: single topical dose
- Body part: thorax
- Volume of test solution applied: 1.0 µL single dose of the appropriate concentration
- Controls: 1.0 µL droplet acetone
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Acetone
- Concentration of vehicle in test medium (stock solution and final test solution): 100%
- Evaporation of vehicle before use: No

- Details of food source: 20% sucrose in water. A solution of the appropriate concentration of the test material in acetone (1 part) with 20% sucrose in water (19 parts) was used. The test material was administered as a single dose of 0.2 mL to each group of 10 bees.
- Method of feeding during study: Via glass tube 50 x 8 mm with a 1.5 mm opening. When the bees had taken all the test solution after 4 hours the dosage tubes were replaced by tubes containing 20% sucrose.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Acetone
- Concentration of vehicle in test medium (stock solution and final test solution): 100% stock solution. 1 part to 19 parts (5%) final test solution.
- Evaporation of vehicle before use: No details
Test organisms (species):
Apis mellifera
Animal group:
Hymenoptera (honeybees)
Details on test organisms:
- Common name: Honey bee
- Source: Mrs. P. Papworth, Four Winds, Houghton, Cambridgeshire
- Date of collection: 25 August 1987 for range-finding test
28 August 1987 for final test
- Cultural background (if honeybees): Sterile female workers
- Disease free: No details
- Kept according to standard practices: No details

- Acclimation period: Bees dosed within 3 - 4 hours of removal from hive.
- Acclimation conditions (same as test or not): No details
- Feeding: 20% sucrose solution. For oral test bees not fed before dosing
- Health during acclimation (any mortality observed): No details
Study type:
laboratory study
Limit test:
Total exposure duration:
48 h
Post exposure observation period:
No details
Test temperature:
24 ± 1ºC
pH (if soil or dung study):
Not applicable
Not reported
Photoperiod and lighting:
Total darkness except for essential procedures.
Details on test conditions:
- Test container (material, size): Cylindrical wire mesh cages 11.5 cm long x 4.0 cm in diameter
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 10
- No. of replicates per control: 2
- No. of replicates per vehicle control: 2

- Photoperiod: Total darkness

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Mortality at 24 and 48 hours


- Range finding study: Yes
- Test concentrations: 5 logarithmically spaced doses from 0.01 to 100 µg test material/bee
- Results used to determine the conditions for the definitive study: Yes. Limit test at 100 µg test material/bee
Nominal and measured concentrations:
Nominal concentrations: 5 logarithmically spaced doses from 0.01 to 100 µg/ bee used for range-finding dose. Final test used one nominal concentration of 100 µg test material/bee.
Reference substance (positive control):
Key result
48 h
Dose descriptor:
Effect conc.:
> 100 µg per animal
Nominal / measured:
Conc. based on:
test mat.
Basis for effect:
Remarks on result:
other: Result for both oral and contact routes.
Details on results:
Technical cloquintocet-mexyl exhibited low toxicity to bees with an LD50 greater than 100 µg/bee by both oral and contact routes.

Results with reference substance (positive control):
No positive control.
Reported statistics and error estimates:
Because only one concentration was tested, no dose-related response was obtained and no statistical analyses were required.
Validity criteria fulfilled:
Technical cloquintocet-mexyl exhibted low toxicity to honey bees (Apis mellifera) with an LD50 greater than 100 µg/bee by both oral and contact routes.
Executive summary:

In a GLP compliant study conducted to EPA FIFRA 71-2 test guideline, a 48 hour toxicity test was conducted with cloquintocet-mexyl to determine the acute oral and contact toxicity to honey bees (Apis mellifera). The LD50 was found to be greater than 100 µg/bee by both routes.

Description of key information

Oral and direct contact LD50 >100 µg/bee

Key value for chemical safety assessment

Additional information