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Ecotoxicological information

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Guideline study performed in compliance with GLP, available as unpublished report, no restrictions, fully adequate for assessment.
Qualifier:
according to guideline
Guideline:
OECD Guideline 207 (Earthworm, Acute Toxicity Tests)
Version / remarks:
(1984)
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
- Name of test material (as cited in study report): Perkacit TBzTD-pd (same as TBzTD)
- Substance type: Mono-constituent substance
- Physical state: Off-white powder
- Storage condition of test material: in the original container and stored under cool conditions until required
- Analytical purity: 96.6% (± 0.7)
- Impurities (identity and concentrations): water: 0.5% (± 0.05), Na2SO4: 0.1% (± 0.01), Di(dibenzylamine sulphate:2.6% (± 0.1)
- Purity test date: 96.6% (± 0.7)
- Lot/batch No.: 1589105180025
Analytical monitoring:
no
Vehicle:
yes
Details on preparation and application of test substrate:
- Method of preparation of test solutions: Fresh formulations of the test material were prepared for each administration. Any dose remaining at completion of administration was disposed of on the same day. The concentrations of the test material in the soil were calculated and expressed gravimetrically in terms of the test material as received and the dry weight of the soil. The found mean water content on Day 1 was used to calculate the concentrations in terms of mg test material per kg of dry soil.
- Method of application to soil surface: On the day of treatment, each jar of soil was sprayed with 2 cm³ of the appropriate test formulation and left open to the air.
- Chemical name of vehicle (organic solvent): Acetone
- Concentration of vehicle in test medium (stock solution and final test solution): The test material was prepared as a solution or suspension in acetone, at the required concentrations.
- Evaporation of vehicle before use: In order to facilitate rapid evaporation of the acetone, the test and control containers were purged with compressed air during soil treatment and immediately afterwards.
Test organisms (species):
Eisenia fetida
Animal group:
annelids
Details on test organisms:
TEST ORGANISM
- Common name: Earthworm (Eisenia fetida fetida). Although E. foetida foetida is not a typical soil-inhabiting species, its susceptibility to chemicals resembles that of true soil-inhabiting species. It is widely accepted as a standard laboratory species.
- Source: Blades Biological (Scarletts Oast, Cowden, Kent, England).
- Age at test initiation (mean and range, SD): The worms were ordered to be adult (at least two months old with clitellum).
- Weight at test initiation (mean and range, SD): individual weight between 350 and 500 mg.

The maintenance material in which they were supplied contained no contaminants which could reasonably be expected to be present in sufficient quantities to affect the outcome of the study. No contaminant assays were performed.

ACCLIMATION
- Acclimation period: The worms were acclimatized to artificial soil for one week before commencement of treatment.
- Acclimation conditions (same as test or not): No data
- Health during acclimation (any mortality observed): No data






Study type:
laboratory study
Substrate type:
artificial soil
Limit test:
yes
Total exposure duration:
14 d
Post exposure observation period:
All surviving animals were killed after assessment on Day 15, by immersion in aqueous 70% v/v ethanol.
Test temperature:
A temperature range of 18 - 21 °C was recorded in the room during the conduct of the study.
pH:
-
Moisture:
A relative humidity range of 52 - 90% R.H. was recorded in the room during the conduct of the study. The high relative humidity values recorded (above 70% R.H.) had no apparent effect on the study outcome.
Details on test conditions:
TEST SYSTEM
- Test container (material, size): 1 dm³ glass jars.
- Amount of soil or substrate: 750 g of wet soil per container
- No. of organisms per container (treatment): 10
- No. of organisms per container (vehicle control): 10
- No. of replicates per treatment group: 4
- No. of replicates per vehicle control: 4

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- Composition (if artificial substrate): Artificial soil, composed of 9.5% dried sphaghnum peat, 19% kaolinite clay, 66.7% fine quartz sand; 4.8% dried rabbit faeces; water added to appr. 35% dry weight
- Pretreatment of soil: The soil ingredients were mixed dry and water was added to bring the moisture content to approximately 35% dry weight. The achieved water content was determined by drying an aliquot from each replicate to constant Weight before treatment, on Days 1 and 8 and at termination on Day 15 (Appendix 3)
- Storage (condition, duration): Wet soil was introduced into the glass jars and sealed until used for study.
- Stability and homogeneity of test material in the medium: No chemical analyses were undertaken to assess the stability, homogeneity or achieved concentrations of the test material in the vehicle.

OTHER TEST CONDITIONS
- Photoperiod: The animals were kept under constant artificial light
- Light intensity: No data

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): Mortality, behaviour, external changes, and weight of the worms after day 7 and day 14 after the start of the treatment. and the worms were inspected and weighed.

VEHICLE CONTROL PERFORMED: yes

TEST CONCENTRATIONS
- Spacing factor for test concentrations: None (limit test)
- Range finding study: Six groups of ten earthworms were exposed for 8 days to TBzTD treated soil and a control group of ten animals was exposed to acetone treated soil.
- Test concentrations:
Concentrations range finding test (mg/kg): 0 (Control), 0.010, 0.113, 1.075, 10.60, 108.2, 1060
Concentrations main test (mg/kg): 1049
- Results used to determine the conditions for the definitive study: Mortalities at day 8 in the sequence of the concentrations listed above: 1/10 (control), 1/10, 0/10, 1/10, 0/10, 0/10, 0/10
Nominal and measured concentrations:
1049 mg/kg (nominal concentration)
Reference substance (positive control):
no
Duration:
14 d
Dose descriptor:
LC50
Effect conc.:
> 1 049 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
ca. 1 049 other: mg/kg
Basis for effect:
other: Highest dose tested, no effects observed
Details on results:
Mortality
- Mortality at end of exposure period: 1/40
- Mortality in controls: 2/40

Body weight gain
- Group mean body weight of adults at beginning of test: 394 mg (control), 384 mg (treatement group)
- Group mean body weight of adults at the end of test: 575 mg (control), 599 mg (treatement group)
- Group mean increment at the endo of the test: 181 mg (control), 215 mg (tretement group)
- Changes in body weigth of live adults (% of initial weight) at end of exposure period:

- Behavioural abnormalities: At the end of test, all surviving animals were in good condition except for one control which was moribund seven days after introduction to vehicle treated soil.
- Other biological observations: The moisture content of the soil on the day of treatment ranged from 40 - 45% water by dry weight of soil. At the study termination on Day 15, the moisture content ranged from 40 - 44%. The values indicated that there was no significant change in soil hydration during the study period.

TABLE 1
Group mortality
Concentration  Mortality on:  Total
(mg TBzTO/kg dry soil )  Day 8  Day 15  
0 (Control)  2/40 0/38 2/40
1049  0/40  1/40 1/40
TABLE 2
Group mean bodyweights
Concentration  Bodyweights (mg) on:  Increment
(mg TBzTD/kg dry soil)  Day 1  Day 8  Day 15 (Day 1 - Day 15)
0 (Control)  394 483 575 181
1049 384 512 599 215
Validity criteria fulfilled:
yes
Conclusions:
The acute toxicity of tetrakis(phenylmethyl)thioperoxydi(carbothioamide) (TBzTD) to soil macro-organisms was carried out under according to a method OECD 207 (Earthworm, Acute Toxicity Tests) with Eisenia fetida.

Under the conditions of this study, the acute median lethal concentration (LC50) of the test material was greater than the regulatory maximum practical concentration (1000 mg/kg dry soil). Accordingly, TBzTD is considered to be of 'low toxicity' to the Earthworm.
Executive summary:

1. The acute toxicity of TBzTD, was investigated in one group of forty earthworms exposed to artificial soil treated with the test material at 1049 mg/kg dry soil. A single group of forty earthworms was exposed to artificial soil treated with the vehicle (acetone) alone.

Mortality and signs of reaction to treatment were recorded seven and fourteen days after the start of the treatment. The survivors were killed at the end of the observation period.

2. The mortality distribution was as follows:

Concentration

(mg / kg dry weight)

Mortality

0

2/40

1049

1/40

3. Apart from one control animal, all surviving worms were in good condition at both the 7 and 14·day examinations.

4. Bodyweight gain was considered to have been unaffected by treatment with TBzTD.

 

5. Under the conditions of this study, the acute median lethal concentration (LC50) was greater than the regulatory maximum practical concentration of 1000 mg/kg dry soil. Accordingly, TBzTD is considered to be of 'low toxicity' to the Earthworm.

Description of key information

The acute toxicity of tetrakis(phenylmethyl)thioperoxydi(carbothioamide) (TBzTD) to soil macro-organisms was carried out under according to a method OECD 207 (Earthworm, Acute Toxicity Tests) with Eisenia fetida. Under the conditions of this study, the acute median lethal concentration (LC50) of the test material was greater than the regulatory maximum practical concentration (1000 mg/kg dry soil). Accordingly, TBzTD is considered to be of 'low toxicity' to the Earthworm.

Key value for chemical safety assessment

Short-term EC50 or LC50 for soil macroorganisms:
1 049 mg/kg soil dw

Additional information

1. The acute toxicity of TBzTD was investigated in one group of forty earthworms exposed to artificial soil treated with the test material at 1049 mg/kg dry soil. A single group of forty earthworms was exposed to artificial soil treated with the vehicle (acetone) alone.

Mortality and signs of reaction to treatment were recorded seven and fourteen days after the start of the treatment. The survivors were killed at the end of the observation period.

2. The mortality distribution was as follows:

Concentration

(mg / kg dry weight)

Mortality

0

2/40

1049

1/40

3. Apart from one control animal, all surviving worms were in good condition at both the 7 and 14·day examinations.

4. Bodyweight gain was considered to have been unaffected by treatment with TBzTD.

5. Under the conditions of this study, the acute median lethal concentration (LC50) was greater than the regulatory maximum practical concentration of 1000 mg/kg dry soil.

Accordingly, TBzTD is considered to be of 'low toxicity' to the Earthworm.

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