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Toxicity to soil macroorganisms except arthropods

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Reference
Endpoint:
toxicity to soil macroorganisms except arthropods: short-term
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 2015-11-13 to 2015-11-28
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 207 (Earthworm, Acute Toxicity Tests)
Version / remarks:
2013
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
Batch No.: 150209
Purity: 97.7wt%
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
other: Eisenia foetida
Details on test organisms:
TEST ORGANISM
- Source: Eisenia foetida(Michaelsen)
- Age at test initiation: Older than 2 months
- Weight at test initiation: an individual weight of 310 mg -333 mg

ACCLIMATION
- Acclimation period: 14 days
- Acclimation conditions: All earthworms were to be obtained and held in the laboratory under the same surroundings before use. They were kept in the artificial soil for 24h before start of the test.
Study type:
laboratory study
Substrate type:
artificial soil
Limit test:
no
Total exposure duration:
14 d
Test temperature:
18.3 °C to 22.0 °C
pH:
5.5 - 6.5
Moisture:
26.9% at start and 25.7% at the end of test
Details on test conditions:
TEST SYSTEM
- Test container (material, size): 1L glass beaker
- No. of replicates per treatment group: 4 replicates
- No. of replicates per control: 4 replicates

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Preparation of artificial soil
The dry constituents were blended in the correct propotions with sphagnum peat 10% (no visible plant remains), kaolin clay 20% (AR%) , industrial sand 70% (particle size between 150-180 μm) and mixed thoroughly, either in a large-scale laboratory mixer or small electric cement mixer. Moisture content was then determined by drying a small sample at 105 °C ± 5 °C and re-weighing. Deionized water was added to give an overall moisture content of 35% of the dry weight, and the medium was thoroughly mixed. The pH was measured as close to pH 5.5 to 6.5 as possible.
- Preparation of test substance solution
10g of a mixture of fine ground quartz sand was mixed with 173 mg, 232 mg, 310 mg, 415 mg and 556 mg test substance respectively and added to 740 g wet artificial soil to form the test substance concentrations of 311 mg/kg dry soil, 416 mg/kg dry soil, 558 mg/kg dry soil, 747 mg/kg dry soil and 1000 mg/kg dry weight.

OTHER TEST CONDITIONS
- Photoperiod: Continuous light
- Light intensity: 720 lx at the beginning of the test and 716 lx at the end of the test.
- Test humidity: The humidity was kept by the humidifier. It was range from 73.0% to 100% during the test period.

EFFECT PARAMETERS MEASURED:
- Normal observation
Any behavioural or pathological symptoms were checked and recorded at 7d and 14d. Sorting the worms from the artificial soil and testing their reaction to a mechanical stimulus at the front end. Earthworms were classified as dead when they did not respond to a gentle mechanical stimulus to the front end.
- Weight: Total weight of earthworms was weighted and the average weight of earthworms was obtained by dividing the number of earthworms at the beginning and at the end of the test.

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 31mg/kg, 97mg/kg, 311 mg/kg and 1000 mg/kg dry weight test substance and blank control was prepared by mixing about 10g of quartz and 740 g of wet artificial soil
- Results used to determine the conditions for the definitive study: The results indicated that the mortality in the blank controls was 0%, which did not exceed 10% at the end of the test. The modified mortality in the test groups (31 mg/kg dry weight, 97 mg/kg dry weight, 311 mg/kg dry weight and 1000 mg/kg dry weight) were 0%, 0%, 5% and 85% respectively. Under the conditions of the present test, the 7d-LC50 of the test substance to earthworm was between 311 mg/kg dry weight - 1000 mg/kg dry weight.
Nominal and measured concentrations:
Nominal: 311 mg/kg dry soil, 416 mg/kg dry soil, 588 mg/kg dry soil, 747 mg/kg dry soil and 1000 mg/kg dry soil of test substance
Reference substance (positive control):
yes
Remarks:
Chloracetamide
Key result
Duration:
14 d
Dose descriptor:
LC50
Effect conc.:
644 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
- Mortality at end of exposure period:
The mortality in the blank controls was 0%, which did not exceed 10% at the end of the test.
The mortality in the test groups were 2.5%, 0%, 17.5%, 82.5% and 100%.
The deaths in the test groups were 1, 0, 5, 31 and 40 on 7th day. The deaths in the test groups were 1, 0, 7, 33 and 40 on 14th day.
The 14d-LC50 of the test substance to earthworm was 644 mg/kg dry soil and its 95% confidence limit was 612 mg/kg dry soil - 678 mg/kg dry soil.
Results with reference substance (positive control):
The 14d-LC50 of reference substance chloracetamide (C2H4CINO) for the Eisenia foetida was 28 mg/kg dry weight, and the 95% confidence limit was between 26 mg/kg dry weight -30 mg/kg dry weight, which was within the range of 10 mg/kg dry weight -100 mg/kg dry weight.
Validity criteria fulfilled:
yes
Conclusions:
The 14d-LC50 of the test substance to earthworm was 644 mg/kg dry soil and its 95% confidence limit was 612 mg/kg dry soil - 678 mg/kg dry soil.
Executive summary:

The test is to evaluate the acute toxicity of the test substance to earthworm according to OECD Guideline 207 (Earthworm, Acute Toxicity Tests).

Five test groups of 311 mg/kg dry soil, 416 mg/kg dry soil, 558 mg/kg dry soil, 747 mg/kg dry soil and 1000 mg/kg dry soil were designed. Four replicates were prepared for each test group by the method.

 

The mortality in the blank controls was 0%, which did not exceed 10% at the end of the test which filled the criteria for a valid test.

The mortality in the test groups were 2.5%, 0%, 17.5%, 82.5% and 100%.

The deaths in the test groups were 1, 0, 5, 31 and 40 on 7th day. The deaths in the test groups were 1, 0, 7, 33 and 40 on 14th day.

 

The 14d-LC50 of the test substance to earthworm was 644 mg/kg dry soil and its 95% confidence limit was 612 mg/kg dry soil - 678 mg/kg dry soil.

Description of key information

The 14d-LC50 of the test substance to earthworm was 644 mg/kg dry soil and its 95% confidence limit was 612 mg/kg dry soil - 678 mg/kg dry soil.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:
644 mg/kg soil dw

Additional information

The test is to evaluate the acute toxicity of the test substance to earthworm according to OECD Guideline 207 (Earthworm, Acute Toxicity Tests).

Five test groups of 311 mg/kg dry soil, 416 mg/kg dry soil, 558 mg/kg dry soil, 747 mg/kg dry soil and 1000 mg/kg dry soil were designed. Four replicates were prepared for each test group by the method.

 

The mortality in the blank controls was 0%, which did not exceed 10% at the end of the test which filled the criteria for a valid test.

The mortality in the test groups were 2.5%, 0%, 17.5%, 82.5% and 100%.

The deaths in the test groups were 1, 0, 5, 31 and 40 on 7th day. The deaths in the test groups were 1, 0, 7, 33 and 40 on 14th day.

 

The 14d-LC50 of the test substance to earthworm was 644 mg/kg dry soil and its 95% confidence limit was 612 mg/kg dry soil - 678 mg/kg dry soil.

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