5,7-dichloro-4-(4-fluorophenoxy)quinoline;quinoxyfen (ISO)

Toxicity to soil macroorganisms except arthropods

Link to relevant study record(s)

Reference

Endpoint:

toxicity to soil macroorganisms except arthropods: short-term

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The test was conducted by keeping the earthworms in samples of a precisely defined artificial soil to which a range of concentrations of the test substance was applied. Mortality was assessed 7 and 14 days after application.

GLP compliance:

yes

Specific details on test material used for the study:

- Substance ID: TSN 100010
- Name of substance: XDE-795 Fungicide
- Purity: 99.19%

Analytical monitoring:

yes

Details on sampling:

- Sampling method: The test substance was extracted from soil by combining a 10 g subsample of soil and 10 ml acetonitrile in a glass vial and sonicating the vial for approximately 10 minutes. The supernatant was removed from the vial, and the procedure was repeated twice more with 5 ml volumes of acetonitrile. The supernatants were combined and approximately 2 ml was filtered through a 0.45 micron filter into an HPLC vial.
- Sample storage conditions before analysis: Refrigerated

Vehicle:

yes

Remarks:

dilution water

Details on preparation and application of test substrate:

- Method of mixing into soil: Appropriate amounts of test substance were added to dry soil in each test vessel and thoroughly mixed. Deionized water was then added to each vessel to achieve a final moisture content of approximately 30% and the media was mixed.
- Controls: Untreated soil
- Chemical name of vehicle: Dilution water

Test organisms (species):

Eisenia fetida

Animal group:

annelids

Details on test organisms:

TEST ORGANISM
- Common name: Earthworm
- Source: Carolina Biological Supply Company, Burlington, North Carolina

ACCLIMATION
- Acclimation period: 96 hours
- Health during acclimation: During acclimation worms were not treated for disease and they were free of apparent sickness, injuries, and abnormalities at the beginning of the test

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Test temperature:

20 ± 2°C

Moisture:

Approximately 30%

Details on test conditions:

TEST SYSTEM
- Test container (material, size): 3.78 liter glass jars with ventilated caps
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 4

PROPERTIES OF SUBSTRATE
- Soil was formulated by combining industrial sand, kaolin clay, and finely ground sphagnum peat in a 70:20:10 ratio by weight. At the beginning of the test the soil had a moisture content of 34.7% and a pH of 5.8. At the end of the test the soil moisture was 34.4%.

OTHER TEST CONDITIONS
- Photoperiod: 24 hour light and 0 hour dark
- Light intensity: 520 lux

EFFECT PARAMETERS MEASURED: The number of surviving organisms and the occurrence of sublethal effects were determined visually and recorded initially and after 7 and 14 days. The time required to burrow was recorded after 0 and 7 days, and the average wet weight of surviving worms was determined at the beginning of the test and after 14 days. Soil temperature was measured and recorded daily in each test vessel and the temperature in one test vessel was recorded continuously during the test.

TEST CONCENTRATIONS
Range finding study
- Test concentrations: 0, 10, 100, 500, and 1000 mg/kg
- Results used to determine the conditions for the definitive study: After 14 days there was at least 90% survival at 0, 10, and 100 mg/kg, 80% survival at 500 mg/kg, and 20% survival at 1000 mg/kg

Nominal and measured concentrations:

Nominal concentrations: 150, 250, 400, 600, 1000 mg/kg
Measured concentrations: 117, 233, 402, 619, 923 mg/kg

Reference substance (positive control):

no

Key result

Duration:

7 d

Dose descriptor:

LC50

Effect conc.:

> 923 other: mg/kg

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: highest concentration tested

Key result

Duration:

14 d

Dose descriptor:

LC50

Effect conc.:

> 923 other: mg/kg

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: highest concentration tested

Key result

Duration:

14 d

Dose descriptor:

NOEC

Effect conc.:

923 other: mg/kg

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

mortality

Remarks on result:

other: highest concentration tested

Validity criteria fulfilled:

yes

Conclusions:

7 and 14 day LC50 (earthworms): >923 mg/kg (highest concentration tested)
14 day NOEC (earthworms): 923 mg/kg (highest concentration tested)

Executive summary:

The acute toxicity of the test substance to the earthworm was perfomed with five concentrations of the test substance and a control at a temperature of 20 ± 2°C. The test media was artificial soil comprised of 70% sand, 20% kaolin clay, and 10% finely ground sphagnum peat moss. Test substance was added to dry artificial soil in the test vessel and thoroughly mixed. Deionized water was then added to each vessel to achieve a final moisture content of approximately 30% and the media was mixed.

The test vessels were 3.87 liter glass jars capped with a ventilated closure. Forty worms (10 per replicate) were exposed to the following nominal concentrations: 0 (control), 150, 250, 400, 600, and 1000 mg/kg. Measured soil concentrations were analytically determined on day 0, 7, and 14. Mean measured concentrations were: ND (none detected at or below the analytical detection limit of 10 mg/kg; control), 117, 233, 402, 619, and 923 mg/kg. Measured concentrations were used for all calculations. Temperature was within acceptable limits throughout the test.

Exposure of worms to the test substance resulted in 7- and 14-day median lethal concentrations (LC50) greater than 923 mg/kg (the highest tested concentration). The 14 day no observed effect concentration (NOEC) in this test was 923 mg/kg.

Description of key information

14-day LC₅₀ (Eisenia fetida): > 923 mg/kg (the highest concentration tested); no guideline followed; Reliability = 2

14-day NOEC (Eisenia fetida): 923 mg/kg (the highest concentration tested); no guideline followed; Reliability = 2

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

923 mg/kg soil dw