Cyanoguanidine

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12-14 September 1984

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

yes

Remarks:

exposure period extended to 48h

GLP compliance:

yes

Remarks:

The study was carried out under conditions of good laboratory practice. Within reason there have been no circumstances that might have affected the quality and integrity of the study.

Specific details on test material used for the study:

PHYSICO-CHEMICAL PROPERTIES
- Melting point: 209 -211 °C
- Water solubility (under test conditions): 3.2 g/100 g water
- Stability in water: Dicyandiamid is stable in neutral aqueous solution for temperatures < 80 °C


OTHER PROPERTIES (if relevant for this endpoint)
- Results of test for ready biodegradability: Dicyandiamid is not readily biodegradable

Analytical monitoring:

no

Details on sampling:

No analytical monitoring.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- first stock solution: 2000 mg Dicyandiamid dissolved in 1l
- from this solution 2.4, 4.5, 8.0, 14, 25, 45, 80, 140 and 250 ml were taken and diluted with dilution water to 0.5 l to prepare the corresponding test solutions, concentration range 10 - 1000 mg/l
- second stock solution: 10000 mg Dicyandiamd in 1l
- from second stock solution 90, 160, 280 and 500 ml were taken and diluted to 0.5l to prepare the more concentrated test soloutions in the concentration range 1800 - 10000 mg/l

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Cultured in the laboratory under standard conditions
- Age at study initiation (mean and range, SD): less than 24 h

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

Not applicable

Hardness:

CaCO3: 210 mg/l

Test temperature:

19 +/- 1 °C

pH:

7.8 - 8.3

Dissolved oxygen:

> 6.3 mg/l

Salinity:

No data

Nominal and measured concentrations:

Nominal concentrattions:
- 13 concentrations: 0, 10, 18, 32, 56, 100, 180, 320, 560, 1000, 1800, 3200, 5600, 10000

Concentrations were not measured

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: 100 ml all-glass beakers, each containing 100 ml test solution
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4


TEST MEDIUM / WATER PARAMETERS
DILUTION WATER
- The dilution water used was DSWL, prepared from groundwater
- Composition:
- Na: 1.19 mmol/l
- K: 0.20 mmol/l
- Ca: 1.36 mmol/l
- Mg: 0.73 mmol/l
- Cl: 2.72 mmol/l
- SO4: 0.73 mmol/l
- HCO3: 1.37 mmol/l


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- mobility and swimming behaviour (see tables 1 and 2)

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

8 118 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CL: 5952 - 11073

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3 177 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks on result:

other: 95 % CL: 2506 - 4028

Duration:

48 h

Dose descriptor:

EC100

Effect conc.:

10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: swimming behaviour

Details on results:

- Behavioural abnormalities: Although in the test solution containing 180 mg/l until and including 3200 mg/l most living animals were mobile according to the definition given in OECD 202, they were swimming less active and with more irregular movements compared to the control animals

Results with reference substance (positive control):

No reference substance

Reported statistics and error estimates:

- Calculation of EC50 (24h and 48h) EC100 and NOEC (both 48h)
- calculation of the 95 % CL for EC50 (24h and 48h)
- slope of concentration-effect curve was 0.47

Validity criteria fulfilled:

yes

Remarks:

No immobilization of daphnids w as observed in the control. During the biological phase of the study no unexpected phenomena were recorded.

Conclusions:

The 24h EC50 (immobilization) was found to be 8118 mg/l, and the 48 h EC50 3177 mg/l.
At 1000 mg/l all animals were mobile after 48h, at 10000 mg/l all animals were immobile after 48h.
Therefore, it can be concluded that Dicyandiamide is practically non-toxic to Daphnia magna.

Executive summary:

The acute toxicity of Dicyandiamid to the fresh-water crustacean Daphnia magna was determined as laid down in OECD Guideline No. 202, but the exposure period was extended to 48h.

Test concentrations of nominal 0, 10, 18, 32, 56, 100, 180, 320, 560, 1000, 1800, 3200, 5600 and 10000 mg/l Dicyandiamd were selected for this study. Four replicates were evaluated per test concentration and control.

The 24h EC₅₀(immobilization) was found to be 8118 mg/l, and the 48 h EC₅₀3177 mg/l. At 1000 mg/l all animals were mobile after 48h, at 10000 mg/l all animals were immobile after 48h.

The slope of the concentration-effect curve was 0.47.

After 48 h exposure at 100 mg/l, the number of mobile animals and their condition, visually assessed, were the same as those of the control animals.

The estimation of the following toxicity values were based on nominal test concentrations:

NOEC(48h): 100 mg/l (based on swimming behaviour)

NOEC(48h): 1000 mg/l (based on mobility)

EC50(48 h): 3177 mg/l

Description of key information

The acute toxicity of Dicyandiamid to the fresh-water crustacean Daphnia magna was determined as laid down in OECD Guideline No. 202, but the exposure period was extended to 48h. 
Test concentrations of nominal 0, 10, 18, 32, 56, 100, 180, 320, 560, 1000, 1800, 3200, 5600 and 10000 mg/l Dicyandiamd were selected for this study. Four replicates were evaluated per test concentration and control. 

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

3 177 mg/L

Additional information

The 24h EC50(immobilization) was found to be 8118 mg/l, and the 48 h EC50 3177 mg/l. At 1000 mg/l all animals were mobile after 48h, at 10000 mg/l all animals were immobile after 48h.

The slope of the concentration-effect curve was 0.47.

After 48 h exposure at 100 mg/l, the number of mobile animals and their condition, visually assessed, were the same as those of the control animals.

The estimation of the following toxicity values were based on nominal test concentrations:

NOEC(48h): 100 mg/l (based on swimming behaviour)

NOEC(48h): 1000 mg/l (based on mobility)

EC50(48 h): 3177 mg/l