4-Ethoxy-2,3-difluoro-4'-methyl-1,1'-biphenyl

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

Study period:

Jan 18, 2016 - Jun 02, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 207 (Earthworm, Acute Toxicity Tests)

GLP compliance:

yes

Remarks:

no OECD GLP

Analytical monitoring:

no

Vehicle:

yes

Remarks:

Acetone

Details on preparation and application of test substrate:

A defined artificial soil of the following composition was used for this assay.
Sphagnum peat 10 % (w/w)
Kaolinite clay (Sigma Aldrich) 20 % (w/w)
Silica sand (screened with 0.2 mm sieve) 70 % (w/w)

Based on the results of preliminary test, the test substance was insoluble in water, but could be dissolved in acetone. The test substance was added into the test system by test substance solvent stock solution.
An aliquot solvent solution was separately added to certain amount of silica sand and the solvent was allowed to evaporate off prior to incorporation into formulated artificial soil with deionised reverse osmosis water. These were mixed by mixer to give blank control, solvent control, and 10, 100, and 1000 mg/kg respectively with a nominal moisture content of 40-60 % by mass of the total water-holding capacity with the deionized water. Test medium preparation process of blank control group was the same with other groups, but without organic solvent and test substance. Test medium preparation process of solvent control was the same with other groups, but without test substance.

Test organisms (species):

Eisenia fetida

Details on test organisms:

TEST ORGANISM
- Common name: Eisenia fetida
- Source: Jiang Su province Jurong Stock Farm. (ID: EF-MKT-150915)
- Age at test initiation (mean and range, SD): no data
- Weight at test initiation (mean and range, SD): 572.25 +/- 6.07 mg

ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions (same as test or not): yes
- Health during acclimation (any mortality observed): no mortality, no other findings

Study type:

laboratory study

Substrate type:

artificial soil

Limit test:

no

Total exposure duration:

14 d

Test temperature:

20.8 - 21.2 °C

pH:

6.28 & 6.48 (start)
6.28 & 6.45 (end)

Moisture:

26.70-29.30 % (start)
26.31-28.93 % (end)

Details on test conditions:

TEST SYSTEM
- Test container (material, size): 1 L glass vessel, closed
- Amount of soil or substrate: 750 g
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 4
- No. of replicates per vehicle control: 4

OTHER TEST CONDITIONS
- Photoperiod: 24 h/day
- Light intensity: 542 - 589 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
day 7 and 14,

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Justification for using less concentrations than requested by guideline:
- Range finding study: 0, 10, 100, 1000 mg/kg dry soil weight
- Test concentrations in definitive study: blank, solvent, 62.5, 125, 250, 500, 1000 mg/kg dry soil weight
- Results used to determine the conditions for the definitive study: range finder results
day 7: 10 % mortality with 1000 mg/kg treatment
day 7: 30 % mortality with 1000 mg/kg treatment

Nominal and measured concentrations:

1000 mg/kg soil

Reference substance (positive control):

yes

Remarks:

Chloroacetamide

Duration:

7 d

Dose descriptor:

LC50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Key result

Duration:

14 d

Dose descriptor:

LD50

Effect conc.:

> 1 000 mg/kg soil dw

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality

Details on results:

The mortalities of the earthworm in the blank control group and solvent control group were 2.5 % and 0 % respectively, which were not more than 10 %, so the test was valid.
The mortalities of the treatment group with the nominal concentration of 1000 mg/kg dry artificial soil weight after 7 and 14 days were 7.5 % and 12.5 % respectively. Under condition of the test, the 7-Day LC50 and the 14-Day LC50 for the test substance to earthworms (Eisenia fetida) based on the nominal test concentrations were both higher than 1000 mg/kg dry soil weight.

Results with reference substance (positive control):

LD50 at about 15 mg/kg soil dw

Reported statistics and error estimates:

Standard statistical methods have been applied for data processing.

Validity criteria fulfilled:

yes

Conclusions:

Under conditions of the test, the 7 -day LD50 and the 14 -day LD50 for the test substance to earthworms (Eisenia fetida) based on nominal test concentrations were higher than 1000 mg/kg dry soil weight.

Executive summary:

In this study, the acute toxicity of the test substance to Eisenia fetida was determined in a 14 days artificial soil test. The study design followed the "OECD, Guidelines for the Testing of Chemicals, 1984, 207 Earthworm, Acute Toxicity Test".

Based on the results of range-finding test, five treatment groups, one blank control group and one solvent control group which had four replicates of 10 worms per concentration were included in definitive test. The nominal concentrations of the treatment groups were 62.5, 125, 250, 500 and 1000 mg/kg dry artificial soil weight. The number of mortalities were determined after 7 and 14 days exposure. 

The mortalities of the earthworm in the blank control group and solvent control group were 2.5 % and 0 % respectively, which were not more than 10 %, so the test was valid. The mortalities of the treatment group with the nominal concentration of 1000 mg/kg dry artificial soil weight after 7 and 14days were 7.5 % and 12.5 % respectively. Under condition of the test, the 7-Day LC50 and the 14-Day LC50 for the test substance to earthworms (Eisenia fetida) based on the nominal test concentrations were both higher than 1000 mg/kg dry soil weight.

Description of key information

Under condition of the test, the 7-Day LC50 and the 14-Day LC50 for the test substance to earthworms (Eisenia fetida) based on the nominal test concentrations were both higher than 1000 mg/kg dry soil weight.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:

1 000 mg/kg soil dw

Additional information

In this study, the acute toxicity of the test substance to Eisenia fetida was determined in a 14 days artificial soil test. The study design followed the "OECD, Guidelines for the Testing of Chemicals, 1984, 207 Earthworm, Acute Toxicity Test".

Based on the results of range-finding test, five treatment groups, one blank control group and one solvent control group which had four replicates of 10 worms per concentration were included in definitive test. The nominal concentrations of the treatment groups were 62.5, 125, 250, 500 and 1000 mg/kg dry artificial soil weight. The number of mortalities were determined after 7 and 14 days exposure. 

The mortalities of the earthworm in the blank control group and solvent control group were 2.5 % and 0 % respectively, which were not more than 10 %, so the test was valid. The mortalities of the treatment group with the nominal concentration of 1000 mg/kg dry artificial soil weight after 7 and 14days were 7.5 % and 12.5 % respectively. Under condition of the test, the 7-Day LC50 and the 14-Day LC50 for the test substance to earthworms (Eisenia fetida) based on the nominal test concentrations were both higher than 1000 mg/kg dry soil weight.