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Toxicity to soil macroorganisms except arthropods

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Endpoint:
toxicity to soil macroorganisms except arthropods: short-term
Type of information:
experimental study
Adequacy of study:
key study
Study period:
February 1985
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 207 (Earthworm, Acute Toxicity Tests)
Deviations:
no
GLP compliance:
yes
Remarks:
The study was carried out under conditions of GLP. Within reason there have been no circumstances that might have affected the quality and integrity of the study.
Analytical monitoring:
no
Details on sampling:
Not applicable
Vehicle:
no
Details on preparation and application of test substrate:
- Method of mixing into soil (if used): solutions containing Dicyandiamide were added to artificial soil and mixed thoroughly during two minutes with an electrical mixer
- Controls: Soil without test substance
Test organisms (species):
Eisenia fetida
Animal group:
annelids
Details on test organisms:
TEST ORGANISM
- Common name: earthworm
- Source: grown in the laboratory in a horse-manure garden soil (1:1) mixture at about 23 °C; grown from stock supplied by NIAC-proefbedrijf, Millseweg 1, Beers (N-B), the Netherlands
- Age at test initiation: 4 months
- Weight at test initiation: 500 mg
Study type:
laboratory study
Substrate type:
artificial soil
Limit test:
no
Total exposure duration:
14 d
Post exposure observation period:
Not applicable
Test temperature:
22 ± 1 °C
pH:
At study initiation: 5.7
Moisture:
At study initiation: 50 % (based on dry constituents)
End of study (after 14 days): 47 %
Details on test conditions:
TEST SYSTEM
- Test container (material, size): 1l all-glass containers with glass lid
- Amount of soil or substrate: 750 g (wet weight) of artificial soil
- No. of organisms per container (treatment): 10
- No. of replicates per treatment group: 4
- No. of replicates per control: 4

SOURCE AND PROPERTIES OF SUBSTRATE (if soil)
- artificial soil
- Composition:
- % sand: 70
- % sphagnum peat: 10
- % clay: 20
- Homogeneity of test material in the medium: solutions containing Dicyandiamide were added to artificial soil and mixed thoroughly during two minutes with an electrical mixer

OTHER TEST CONDITIONS
- Photoperiod: continous illumination
- Light intensity: at least 400 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- mortality of worms, after 7 and 14 days
- appearance and behaviour (visual assessment), after 7 and 14 days
- weight of worms after 14 days
- after 7th day worms and medium were replaced in their test containers
Nominal and measured concentrations:
Nominal concentrations: 3200, 1800, 1000, 560, 320, and 0 mg of test substance per kg of dry artificial soil.
Reference substance (positive control):
no
Duration:
14 d
Dose descriptor:
LC50
Effect conc.:
> 3 200 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mortality
Remarks on result:
other: No LC50 value could be calculated, because the test substance did not cause any mortality at any of the concentrations tested (see table 1).
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
1 800 mg/kg soil dw
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: body weight
Details on results:
- Mortality at end of exposure period: No mortality
- Average mass of adults at beginning of test: see Table 1
- Changes in body weigth of live adults at end of exposure period: see Table 1
- Morphological abnormalities: No data
- Behavioural abnormalities: No data
- Other biological observations: No
Results with reference substance (positive control):
Not applicable
Reported statistics and error estimates:
Not necessary - no mortality observed.

Table 1: Number of living worms in the course of the test, and tehri average weight at t=0 d and t=14 d

 

 

Concentration of dicyandiamide (mg/kg of dry artificial soil)

Time (days)

Parameter

0

320

560

1000

1800

3200

0

Number worms

40

40

40

40

40

40

 

Weight (mg)

497

480

477

499

483

430

7

Number worms

401)

402)

402)

402)

402)

402)

14

Number worms

401)

402)

402)

402)

402)

402)

 

Weight (mg)

413

412

423

442

410

389

1)     appearance and behaviour of worms normal (visually estimated)

2)     appearance and behaviour of worms same as controls

3) appearance and behaviour of worms somewhat less good than the controls

 According to the guideline, the worms are not fed during the test; therefore worm weights decrease.

 

Validity criteria fulfilled:
yes
Remarks:
Conditions for validity of the test: The mortality in the controls should not exceed 10 per cent at the end of either test.
Conclusions:
The toxicity of the substance to earthworms was low, with no mortality observed up to the highest test concentration of 3200 mg of dicyandiamide per kg dry artificial soil; the no-obsereved effect concentration in terms of body weight was greater than or equal to 1000 mg per kg, and less than 1800 mg per kg dry artificial soil. However, this is not a parameter of interest in an acute earthworm study.
Executive summary:

Dicyandiamide, technically pure, was tested for acute toxicity towards the earthworm species Eisenia fetida in accordance with OECD guideline 207 at five concentrations of 3200, 1800, 1000, 560, 320, and 0 mg test substance per kg dry artificial soil.

The toxicity of the substance to earthworms was low, with no mortality observed up to the highest test concentration of 3200 mg dicyandiamide per kg of dry artificial soil.

Endpoint:
toxicity to soil macroorganisms except arthropods: long-term
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:

Description of key information

Technically pure dicyandiamide was tested for acute toxicity towards the worm species Eisenia foetida in accordance with OECD guideline no. 207 at five concentrations of 3200, 1800, 1000, 560, 320, and 0 mg test substance per kg dry artificial soil. 
The toxicity of the substance to earthworms was low, the 14d LC50 being in excess of 3200 mg dicyandiamid per kg dry artificial soil; the no-obsereved effect concentration was greater than or equal to 1000 mg per kg, and less than 1800 mg per kg dry artificial soil.

Key value for chemical safety assessment

Additional information

The toxicity of the substance to earthworms was low, the 14d LC50 being in excess of 3200 mg dicyandiamide per kg dry artificial soil; the no-obsereved effect concentration was greater than or equal to 1000 mg per kg, and less than 1800 mg per kg dry artificial soil.