Cyanamide

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:

1983

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)

Version / remarks:

”Daphnia sp., 14 day Reproduction Test, including an Acute Immobilisation Test”, 1981

Deviations:

no

Remarks:

, however, the test concentrations are not quantified during the test duration. It is assumed that the test is valid without analytical data as cyanamide is known to be hydrolytically stable in water at the concentrations tested.

GLP compliance:

no

Analytical monitoring:

no

Details on sampling:

No sampling

Vehicle:

no

Details on test solutions:

Not indicated

Test organisms (species):

Daphnia magna

Details on test organisms:

- Unfed Daphnia magna, < 24 hours old

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

No post exposure observation period

Hardness:

Not indicated

Test temperature:

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges.

pH:

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges.

Dissolved oxygen:

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges.

Salinity:

Freshwater

Nominal and measured concentrations:

Nominal concentrations of 1.8, 3.2, 5.6, 10.0, 18.0, 32.0, 56.0, 100.0, 180.0 and 320.0 mg of a 49 % (w/w) aqueous solution of cyanamide/L.

Details on test conditions:

Five daphnids were used per replicate. The test was performed with four replicates per treatment.

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.2 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

LC50

Effect conc.:

4.3 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.6 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mobility

Details on results:

The test concentrations were not measured during the test. A summary of the findings is presented in Table A7.4.1.2/01-1. There were no test concentration related immobility or mortal effects below 5.6 mg of a 49 % (w/w) aqueous solution of cyanamide/L. The highest concentration causing no immobility or mortality was 3.2 mg/L and the lowest concentration causing 100 % immobility or mortality was 18.0 mg/L.

Results with reference substance (positive control):

No reference substance

Reported statistics and error estimates:

Not indicated

Immobilisation of unfed Daphnia magna exposed to a 49 % (w/w) aqueous solution of cyanamide for 48 hours in an unaerated, static acute test:

 

Nominal concentration of a 49 % (w/w) aqueous solution of cyanamide (mg/L)	Mortality (No. dead/No. at test start)		Immobility (No. immobile/No. at test start
	24 hours	48 hours	24 hours	48 hours
Water Control	0/20	0/20	0/20	0/20
1.8	0/20	0/20	0/20	0/20
3.2	0/20	0/20	0/20	0/20
5.6	1/20	3/20	1/20	6/20
10.0	4/20	11/20	7/20	18/20
18.0	13/20	20/20	15/20	20/20
32.0	11/20	20/20	11/20	20/20
56.0	12/20	20/20	12/20	20/20
100.0	12/20	20/20	13/20	20/20
180.0	19/20	20/20	20/20	20/20
320.0	20/20	20/20	20/20	20/20

 

Acute toxicity (48 h) of Cyanamide to daphnids – Summary of endpoints:

Endpoint	Nominal concentration of 49 % (w/w) aqueous solution of cyanamide
EC50	6.5 mg/L (3.2 mg as/L)
LC50	8.8 mg/L (4.3 mg as/L)
No observed effect concentration (NOEC)	3.2 mg/L (1.6 mg as/L)

 

Validity criteria fulfilled:

not specified

Conclusions:

The 48-hour EC50 in Daphnia magna was 6.5 mg of a 49 % (w/w) aqueous solution of cyanamide/L (equivalent to 3.2 mg as/L), based on immobilisation of the test animals. The 48-hour LC50 were 8.8 mg/L, based on mortality. The NOEC is estimated to be 3.2 mg/L (equivalent to 1.6 mg as/L). Since it is difficult to differentiate between immobile and dead daphnids, immobility is used as the relevant endpoint.

Executive summary:

The acute toxicity of Alzodef (a 49 % (w/w) aqueous solution of cyanamide) to unfed Daphnia magna (< 24 hours old) was determined in an unaerated, static, 48-hour test. Treatments consisted of a diluted water control, and nominal concentrations of 1.8, 3.2, 5.6, 10.0, 18.0, 32.0, 56.0, 100.0, 180.0 and 320.0 mg of a 49 % (w/w) aqueous solution of cyanamide/L. Five daphnids were used per replicate. The test was performed with four replicates per treatment.

 

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges. There were no test concentration related immobility or mortal effects below 5.6 mg of a 49 % (w/w) aqueous solution of cyanamide/L. The highest concentration causing no immobility or mortality was 3.2 mg/L and the lowest concentration causing 100 % immobility or mortality was 18.0 mg/L.

 

The 48-hour EC50 in Daphnia magna was 6.5 mg of a 49 % (w/w) aqueous solution of cyanamide/L (equivalent to 3.2 mg as/L), based on immobilisation of the test animals. The 48-hour LC50 were 8.8 mg/L, based on mortality. The NOEC is estimated to be 3.2 mg/L (equivalent to 1.6 mg as/L). Since it is difficult to differentiate between immobile and dead daphnids, immobility is used as the relevant endpoint.

Description of key information

The acute toxicity of the test substance cyanamide (Alzodef: 49 % (w/w) aqueous solution of cyanamide) to Daphnia magna was examined in one available study. In this static,

48 hours test the calculated EC50 was 3.2 mg of pure active ingredient (ai) cyanamide/L, NOEC of 1.6 mg ai/L and a LC50 of 4.3 mg ai/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

3.2 mg/L

Additional information

The acute toxicity of Alzodef (a 49 % (w/w) aqueous solution of cyanamide) to unfed Daphnia magna (< 24 hours old) was determined in an unaerated, static, 48-hour test. Treatments consisted of a diluted water control, and nominal concentrations of 1.8, 3.2, 5.6, 10.0, 18.0, 32.0, 56.0, 100.0, 180.0 and 320.0 mg of a 49 % (w/w) aqueous solution of cyanamide/L. Five daphnids were used per replicate. The test was performed with four replicates per treatment.

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges. There were no test concentration related immobility or mortal effects below 5.6 mg of a 49 % (w/w) aqueous solution of cyanamide/L. The highest concentration causing no immobility or mortality was 3.2 mg/L and the lowest concentration causing 100 % immobility or mortality was 18.0 mg/L.

The 48-hour EC50 in Daphnia magna was 6.5 mg of a 49 % (w/w) aqueous solution of cyanamide/L (equivalent to 3.2 mg as/L), based on immobilisation of the test animals. The 48-hour LC50 were 8.8 mg/L, based on mortality. The NOEC is estimated to be 3.2 mg/L (equivalent to 1.6 mg as/L). Since it is difficult to differentiate between immobile and dead daphnids, immobility is used as the relevant endpoint.