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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:
supporting study
Study period:
6 June - 29 September 2013
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Chinese GLP used
Qualifier:
according to guideline
Guideline:
OECD Guideline 207 (Earthworm, Acute Toxicity Tests)
Deviations:
yes
Remarks:
The artificial soil used in the test was 750 g (dry weight) which deviated from "750 g (wet weight)" described in the protocol.
GLP compliance:
no
Remarks:
Chinese GLP
Analytical monitoring:
no
Vehicle:
no
Details on preparation and application of test substrate:
- Method of mixing into soil (if used): The test substance was directly added into the soil. A total amount of 10 g mixture of the test substance and dry soil was prepared firstly and then mixed with 740 g dry weight of soil for each test container. The medium was thoroughly mixed and deionised water was added finally to give an overall moisture content of about 35 per cent of the dry weight. Moisture content was determined by drying a small sample at 105°C and re-weighing. The complete mixture was moist but not so wet that water appears when the artificial soil is compressed.

- Controls: A blank control group, comprising the same number of test worms as each treatment, was also treated with the same methods without using the test substance.

- Chemical name of vehicle (organic solvent, emulsifier or dispersant): No vehicle
Test organisms (species):
Eisenia fetida
Animal group:
annelids
Details on test organisms:
TEST ORGANISM
- Common name: earthworm
- Source: The worms were obtained from an earthworm nursery of Nanjing city in China.
- Age at test initiation (mean and range, SD): two months old with clitellum
- Weight at test initiation (mean and range, SD): individual weight of 348 - 431 mg and the average weight of 396 mg.

ACCLIMATION
- Acclimation period: Before the test, the worms were acclimated in non polluted soil for 24 days. The worms were then pre-cu1tured in test soils for another 24 h.
- Acclimation conditions (same as test or not): Not confirmed
- Health during acclimation (any mortality observed): Not reported
Study type:
laboratory study
Substrate type:
artificial soil
Limit test:
yes
Total exposure duration:
14 d
Test temperature:
20°C - 22°C
pH:
range 6.0 - 6.5
Moisture:
range of 31% to 36%
Details on test conditions:
TEST SYSTEM
- Test container (material, size): Glass spotless beakers, 1 l
- Amount of soil or substrate: A total amount of 10 g mixture of the test substance and dry soil was prepared first and then mixed with 740 g dry weight of soil for each test container.
- 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: n/a

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
Artificial soil test substrate was prepared as follows:
a) 10 per cent sphagnum peat (PH 6.0, no visible plant remains, finely ground, dried).
b) 20 per cent kaolin clay (kaolinite content preferably above 30 per cent).
c) 70 per cent industrial sand (fine sand should be dominant with 60 per cent of the particles between 50 and 200 microns).
d) pH is adjusted to 6.0 by addition of calcium carbonate.
The dry constituents were blended in the correct proportions and mixed thoroughly with a large-scale laboratory mixer.
The Total Organic Carbon (TOC) for the artificial soil was 1.2 g/kg average.

OTHER TEST CONDITIONS
- Photoperiod: continuous light
- Light intensity: 400 lux to 800 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): mortality at 7 and 14 days. Besides the number of dead earthworms, behavioural and pathological abnormalities (e.g. lethargic or rigid worms) were determined during each mortality assessment.

VEHICLE CONTROL PERFORMED: yes/no: n/a

TEST CONCENTRATIONS
- Spacing factor for test concentrations: Limit test
- Justification for using less concentrations than requested by guideline: Range finding test showed no toxicity at 1000 mg/kg soil dw.
- Range finding study
- Test concentrations: 10, 100 and 1000 mg/kg soil dw.
- Results used to determine the conditions for the definitive study: mortality
Nominal and measured concentrations:
Limit test at 1000 mg/kg soil dw
Reference substance (positive control):
yes
Remarks:
2-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
Remarks on result:
other: 95% CL: 21.2 ~ 30.0 mg/kg (dry soil)
Details on results:
- Mortality at end of exposure period: no mortality
- Total mass of adults at beginning of test: average 396 mg/worm
- Changes in body weight of live adults (% of initial weight) at end of exposure period: not reported - end mean weight in control = 381.75 mg. End mean weight in 1000 mg/kg test organisms = 381.5 mg.
- No. of offspring produced: n/a
- No. of unhatched cocoons: n/a
- Morphological abnormalities: None
- Behavioural abnormalities: None
- Other biological observations:
Results with reference substance (positive control):
- Results with reference substance valid? Yes
- Relevant effect levels: 14-d LC50 25.1 mg/kg soil dw
- Other: 95% confidence limit of 21.2 - 30.0 mg/kg (dry soil)

No dead worms were observed in treatments and control. The results of the range-finding test and the Limit Test both showed that the 14d-LC50 to Eisenia foetida in artificial soil was greater than 1000 mg/kg soil dry weight.

Validity criteria fulfilled:
yes
Conclusions:
The result indicated that the 14d-LC50 of the test substance in the artificial soil was greater than 1000 mg/kg dry weight soil. The highest concentration causing no mortality for 14d (14d-LC0) was 1000 mg/kg dry weight soil.
Executive summary:

The test was conducted to determine the acute toxicity of test substance to earthworm according to "The guidelines for the testing of chemicals" (HJrr 153-2004) and "The guidelines for the testing of chemicals" (SEP A. Beijing: China Environmental Sciences Press. 2004); while with reference to Procedure 207 of the 'Guidelines for Testing of Chemicals' of the OECD: "Earthworm. Acute Toxicity Tests" (1984) etc. During this test. the artificial soils was used with the moisture content of the test medium controlled in range of 31 % to 36% with pH from 6.0 to 6.5 The test conditions were maintained as follows: temperature of 20°C to 22°C. humidity of 80% to 85% and continuous light with intensity of 400 lux to 800 lux. Based on the result of range-finding test and the Limit Test, the 14 d-LC50 of the test substance in the artificial soil was determined to be greater than 1000 mg/kg dry weight soil. The highest concentration causing no mortality (14 d-LC50) was 1000 mg/kg dry weight soil.

Description of key information

Short-term toxicity to earthworms: 14-d LC50 >1000 mg/kg soil dw, NOEC 1000 mg/kg soil dw (nominal concentration) (highest concentration tested) (OECD 207). The LC50 is equivalent to >847 mg/l when expressed in terms of the hydrolysis product, 3-(trihydroxysilyl)propyl-(2E,4E)-2,4-hexadienoate

Key value for chemical safety assessment

Additional information

A 14 day LC50 value of >1000 mg/kg soil dw and a NOEC value of 1000 mg/kg soil dw (highest concentration tested) (nominal concentrations) have been determined for the effects of 3-(trimethoxysilyl)propyl-(2E,4E)-hexa-2,4-dienoate on mortality of Eisenia fetida.

The results may be expressed in terms of concentration of the hydrolysis product, 3-(trihydroxysilyl)propyl-(2E,4E)-2,4-hexadienoate, by applying a molecular weight correction: (MW of silanol = 232.31 / MW of parent = 274.37) * >1000 = >847 mg/kg soil dw as 3-(trihydroxysilyl)propyl-(2E,4E)-2,4-hexadienoate.

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