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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 2018-11-16 to 2018-11-30
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 (incl. QA statement)
Specific details on test material used for the study:
Batch No.: 707001
Purity: 98.5%
Analytical monitoring:
no
Vehicle:
no
Details on preparation and application of test substrate:
2.5002 g test item was weighed and mixed with 50 g industrial sand. The treated sand was mixed thoroughly with proper artificial soil (dry weight was 2450 g). Proper distilled water was added to adjust the moisture content to about 30% of dry weight and mixed to be homogeneous. The complete mixture was moist but not so wet that water appears when the artificial soil was compressed. For each treated soil, four 750 g of the wet test medium were weighed and put into 4 labeled test containers.
A concurrent control group with four replicates maintained under identical conditions only without test item application was performed in parallel. 50 g industrial sand was applied to properly pre-moistened artificial soil (dry weight was 2450 g). Proper distilled water was added to adjust the moisture content to about 30% of dry weight and mixed to be homogeneous. After the same treatment procedure as with the test medium, the sample was used as the control medium.
Test organisms (species):
Eisenia fetida
Animal group:
annelids
Details on test organisms:
TEST ORGANISM
- Common name: Earthworm (Eisenia foetida)
- Source: Chenggong Earthworm Raising Farm in Dongli District, Tianjin
- Age at test initiation: at least two months old with clitellum
- Weight at test initiation: 300.0 mg to 600.0 mg

ACCLIMATION
- Acclimation period: 24 hours
- Acclimation conditions: same as test
Study type:
laboratory study
Substrate type:
artificial soil
Limit test:
yes
Total exposure duration:
14 d
Test temperature:
19.8-20.4 °C
pH:
5.69 and 5.76 for control and test medium, respectively
Moisture:
68-87 %
Details on test conditions:
TEST SYSTEM
- Test container (material, size): All glass rectangle jar (height: 19cm×length: 12 cm×width: 9 cm), covered with glass lids
- 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

- Artificial soil:
The artificial soil was prepared as follows:
a) 10 per cent sphagnum peat (as close to pH 5.5 to 6.0 as possible, no visible plant remains, finely ground, dried to measure moisture content);
b) 20 per cent kaolin clay (kaolinite content is about 85 per cent);
c) 70 per cent industrial sand (fine sand should be dominant with more than 50 per cent of the particles between 50 and 200 microns);
According to above proportions, prepare 2 groups of 2500 g artificial soil for the test (50 g industrial sand was deducted from amount of industrial sand to use for mixing with test item). The dry constituents are blended in the correct proportions and mixed thoroughly in blender. After test item application, the moisture content was adjusted to about 30-35% (the mixture should be moist but not so wet that water appears when the artificial soil is compressed).


OTHER TEST CONDITIONS
- Photoperiod: Continuous light
- Light intensity: 552-661 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Mortality and reaction to a mechanical stimulus at the front end: at the 7th and 14th day
- Body weight: At the start and the end of the test
- Soil moisture content: At the start and at the end of the test, 1 replicate at the start and 4 replicates at the end
- Soil pH: At the start of the test, 1 replicate was measured in test group and control group.

VEHICLE CONTROL PERFORMED: NA

TEST CONCENTRATIONS
- Range finding study
- Test concentrations: 10, 100 and 1000 mg/kg dry soil weight, a control group
- Results used to determine the conditions for the definitive study: There was no mortality or abnormal toxic signs observed on 7 and 14 days observation.
Nominal and measured concentrations:
Nominal: 1000 mg/kg dry soil weight
Reference substance (positive control):
yes
Remarks:
chloracetamide
Key result
Duration:
14 d
Dose descriptor:
LC50
Effect conc.:
> 1 000 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Details on results:
- Body Weights: Comparing with the weights at the beginning, the body weights at the end decreased slightly both in the control and test group.
- Moisture Content of Test Medium: The moisture content was 29.1% and 29.3% for control and test medium at the beginning of the test, and was in the range of 28.3%-29.8% at the end of the test.
- Toxic Signs: During the exposure period, there was no mortality or abnormal signs observed at control group, so the test was valid.
There was no mortality or abnormal signs observed at the test group.
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: The 14-days LC50 of the reference substance to earthworm is 21.1 mg/kg dry soil weight, with 95% confidence limits of 17.7-25.1 mg/kg dry soil weight,which met the requirement of 20-80 mg/kg dry soil weight in the SOP.
Reported statistics and error estimates:
This test is a limit test, so toxicity effect is determined directly from the test results.
Validity criteria fulfilled:
yes
Conclusions:
According to the result, the 14-day LC50 of test item was greater than 1000 mg/kg dry soil weight under the test condition in this facility.
Executive summary:

This study was performed to assess the acute toxicity of test item to the earthworm (Eisenia foetida) based on OECD 207.

Based on the results of the preliminary test, the definitive study was conducted with a limit concentration of 1000 mg/kgdry soil weight. A concurrent control group was conducted in parallel. For the test and control group, 4 replicates were used with 10 worms in each replicate. Artificial soil was used in this study. The test duration was 14 days, assessment of mortality and abnormal signs was conducted at 7 and 14 day of test.

During the exposure period,there was no mortality or abnormal signs observed at control group, so the test is valid.

There was no mortality or abnormal signs observed at the test group.

According to the results, the 14-days LC50 of test item was greater than 1000 mg/kgdry soilweightunder the test condition in this facility.

Description of key information

This study was performed to assess the acute toxicity of test item to the earthworm (Eisenia foetida) based on OECD 207.

There was no mortality or abnormal signs observed at the test group.

According to the results, the 14-days LC50 of test item was greater than 1000 mg/kgdry soilweightunder the test condition in this facility.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:
1 000 mg/kg soil dw

Additional information

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