Cyanamide

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1985-02-11 until 1985-02-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Committee on Methods for Toxicity Tests with Aquatic Organisms (C.E. Stephan, Chairman) (1975). Methods for Acute Toxicity Tests with Fish, Macroinvertebrates and Amphibians. Environmental Protection Agency, Ecological Research Series EPA 660/3-75-009

Deviations:

yes

Remarks:

see fild below

Qualifier:

according to guideline

Guideline:

other: American Public Health Association (1980). Standard Methods for the Examination of Water and Wastewater. 15th ed. Washington, DC. 1134 p

Deviations:

yes

Remarks:

see fild below

Principles of method if other than guideline:

The areas of deviation from the OECD guideline 203 (adopted 1992) are: Analyses of the test solutions were not performed in this study. Though no analyses of the cyanamide concentration in the test media were performed, it can be assumed that the concentration maintained was stable throughout the whole test, as cyanamide is known to be hydrolytically stable. Furthermore, in the algal inhibition test, the analyses show that no degradation occurred during the test period, which was 96 hours.

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

No sampling

Vehicle:

no

Details on test solutions:

not indicated

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Rainbow trout, Oncorhynchus mykiss (formerly: Salmo gairdneri)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

no post exposure period

Hardness:

not indicated

Test temperature:

Test solutions were maintained between 12.5 and 13.0°C.

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 was used.

Nominal and measured concentrations:

Nominal concentrations of 64.8, 108.0, 180.0, 300.0, and 500.0 mg of a 49% aqueous solution of cyanamide/L.

Details on test conditions:

The acute toxicity of an aqueous solution of Hydrogen cyanamide (a 49% (w/w) aqueous solution of cyanamide) to unfed Rainbow trout, Oncorhynchus mykiss (formerly: Salmo gairdneri), was determined in an unaerated, static, 96-hour test. Treatments consisted of a water control, and nominal concentrations of 64.8, 108.0, 180.0, 300.0, and 500.0 mg of a 49% aqueous solution of cyanamide/L. Test vessels containing 10 fish each were exposed to each treatment concentration and control. Test solutions were maintained between 12.5 and 13.0°C.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

45.6 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

31.8 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Details on results:

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges. Analyses of the test solutions were not performed in this study. Mortality or sublethal effects were observed in all treatment groups. The lowest concentration causing 100 % mortality was 180.0 mg of a 49% aqueous solution of cyanamide/L. Surviving fish exhibited effects such as quiescence, hyperexcitability, sounding, dark coloration, varied discoloration, erratic swimming or ceased swimming.

Results with reference substance (positive control):

No reference

Reported statistics and error estimates:

Not indicated

Sublethal observations / clinical signs:

Observed mortality of Rainbow trout,Oncorhynchusmykiss, exposed to a 49% aqueous solution of Cyanamide for 96 hours in an unaerated, static, acute test

Nominal concentrations of a 49% (w/w) aqueous solution of cyanamide (mg/L)	Cumulative mortality (No. dead / No. at test start)
	24 h	48 h	72 h	96 h
Water Control	0/10	0/10	0/10	0/10
64.8	0/10	1/10	1/10	1/10
108.0	0/10	1/10	3/10	7/10
180.0	0/10	5/10	10/10	10/10
300.0	2/10	10/10	10/10	10/10
500.0	10/10	10/10	10/10	10/10

 

 

Observed sublethal effects on rainbow trout,Oncorhynchus mykiss, exposed to a 49% aqueous solution of cyanamide for 96 hours in an unaerated, static, acute test

 

Nominal concentrations of a 49% (w/w) aqueous solution of cyanamide (mg/L)	Sublethal effects (No. affected / No. at test start)
	24 h	48 h	72 h	96 h
Water Control	0/10	0/10	0/10	0/10
64.8	0/10	9d/10	2^d3^f/10	3^d6^d,g/10
108.0	1^c9^d/10	9^d/10	3^d,b3^a/10	3^d,e/10
180.0	1^c9^d/10	5^d,b/10	L	L
300.0	4^b2^a2^d/10	L	L	L
500.0	L	L	L	L

a   erratic swimming

b   dark discolored

c   ceased swimming

d   quiescent

e   varied discolored

f    hyperexciteable

g   sounding

L   total mortality

 

Validity criteria fulfilled:

not specified

Conclusions:

The 96-hour LC50 for the Rainbow trout was 93.0 mg of a 49% aqueous solution of cyanamide/L (equivalent to 45.6 mg of as/L, nominal not measured). The observed 96-hour no-effect concentration was less than 64.8 mg of a 49% aqueous solution of cyanamide/L (equivalent to 31.8 mg of as/L).

Executive summary:

The acute toxicity of an aqueous solution of Hydrogen cyanamide (a 49% (w/w) aqueous solution of cyanamide) to unfed Rainbow trout, Oncorhynchus mykiss (formerly: Salmo gairdneri), was determined in an unaerated, static, 96-hour test. Treatments consisted of a water control, and nominal concentrations of 64.8, 108.0, 180.0, 300.0, and 500.0 mg of a 49% aqueous solution of cyanamide/L. Test vessels containing 10 fish each were exposed to each treatment concentration and control. Test solutions were maintained between 12.5 and 13.0°C.

 

The 96-hour LC50 for the Rainbow trout was 93.0 mg of a 49% aqueous solution of cyanamide/L (equivalent to 45.6 mg of as/L, nominal not measured). The observed 96-hour no-effect concentration was less than 64.8 mg of a 49% aqueous solution of cyanamide/L (equivalent to 31.8 mg of as/L).

Reference 2

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1985-07-18 until 1985-07-22

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Committee on Methods for Toxicity Tests with Aquatic Organisms (C.E. Stephan, Chairman) (1975). Methods for Acute Toxicity Tests with Fish, Macroinvertebrates and Amphibians. Environmental Protection Agency, Ecological Research Series EPA-660/3-75-009.

Deviations:

yes

Remarks:

, see in the field below

Qualifier:

according to guideline

Guideline:

other: American Public Health Association (1980). Standard Methods for the Examination of Water and Wastewater. 15th ed. Washington, DC. 1134 p.

Deviations:

yes

Remarks:

, see in the field below

Principles of method if other than guideline:

The areas of deviation from the OECD guideline 203 (adopted 1992) are: Analyses of the test solutions were not performed in this study. The fish length of 34±3.6 mm is lower than the recommended fish length of 50±10 mm.
These deviations had no effect on the validity of the study. Though no analyses of the cyanamide concentration in the test media were performed, it can be assumed that the concentration maintained was stable throughout the whole test, as cyanamide is known to be hydrolytically stable. Furthermore, in the algal inhibition test (Seyfried 2000, 823-003; 8.2/09), the analyses show that no degradation occurred during the test period, which was 96 hours.

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

No sampling

Vehicle:

no

Details on test solutions:

Not indicated

Test organisms (species):

Oncorhynchus mykiss (previous name: Salmo gairdneri)

Details on test organisms:

Not indicated

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

No post exposure period

Hardness:

Not indicated

Test temperature:

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges. Analyses of the test solutions were not performed in this study.

pH:

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges. Analyses of the test solutions were not performed in this study.

Dissolved oxygen:

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges. Analyses of the test solutions were not performed in this study.

Salinity:

Freshwater

Nominal and measured concentrations:

Treatments consisted of a water control and nominal concentrations of 31.2, 62.5, 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L.

Details on test conditions:

The acute toxicity of LH 21,810 A (49% (w/w) solution of cyanamide) to unfed fingerling rainbow trout, Oncorhynchus mykiss (formerly: Salmo gairdneri), was determined in an unaerated, static, 96-hour test. Treatments consisted of a water control, and nominal concentrations of 31.2, 62.5, 125.0, 250.0, 500.0, and 1000.0 mg of a 49% aqueous solution of cyanamide/L. Test vessels containing 10 fish each were exposed to each treatment concentration and control. Test solutions were maintained between 11 and 13°C.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

88.2 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

other: lack of mortality and abnormal effects

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

30.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

other: lack of mortality and abnormal effects

Details on results:

There were no mortality below 125.0 mg of a 49% aqueous solution of cyanamide/L and the lowest concentration causing 100% mortality was 250.0 mg of a 49% aqueous solution of cyanamide /L. Surviving fish exhibited effects such as loss of equilibrium, dark discoloration and/or they were found on the bottom of test chambers at the test concentration of 125.0, 250.0, 500.0, and 1000.0 mg of a 49% aqueous solution of cyanamide /L during the 96-hour exposure period.

Results with reference substance (positive control):

No positive control

Reported statistics and error estimates:

Not indicated

Sublethal observations / clinical signs:

Observed mortality of rainbow trout, Oncorhynchus mykiss, exposed to a 49% aqueous solution of cyanamide for 96 hours in an unaerated, static, acute test:

Nominal concentrations of a 49% aqueous solution of cyanamide (mg/L)	Cumulative mortality (No. dead / No. at test start)
	24 h^a	48 h^a	96 h^a
Water Control	0/10	0/10	0/10
31.2	0/10	0/10	0/10
62.5	0/10	0/10	0/10
125.0	0/10	0/10	0/10
250.0	0/10	0/10	10/10
500.0	0/10	10/10	10/10
1000.0	10/10	10/10	10/10

 

Acute toxicity to rainbow trout–Summary of endpoints:

Test substance	49 % (w/w) aqueous solution of Cyanamide
Test object	Rainbow trout (Oncorhynchus mykiss)
Test duration	96 h
LC50	180.0 mg/L
	88.2 mg of the pure ai/L
No observed effect concentration (NOEC)	62.5 mg/L
	30.6 mg of the pure ai/L

 

Validity criteria fulfilled:

not specified

Conclusions:

The 96-hour LC50 for the rainbow trout was 180.0 mg of a 49% aqueous solution of cyanamide/L (equivalent to 88.2 mg of the pure a.i./L). The results indicated a 96-hour NOEC (no observed effect concentration) of 62.5 mg of a 49% aqueous solution of cyanamide/L (equivalent to 30.6 mg of the pure a..i/L), which was based on the lack of mortality and abnormal effects.

Executive summary:

The acute toxicity of LH 21.810 (a 49% (w/w) aqueous solution of cyanamide) to unfed fingerling rainbow trout, Oncorhynchus mykiss (formerly: Salmo gairdneri) was determined in a static, 96-hour test. Treatments consisted of a water control and nominal concentrations of 31.2, 62.5, 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. Test vessels containing 10 fish each were exposed to each treatment concentration and control. There were no mortality below 125.0 mg of a 49% aqueous solution of cyanamide/L and the lowest concentration causing 100% mortality was 250.0 mg of a 49% aqueous solution of cyanamide /L. Surviving fish exhibited effects such as loss of equilibrium, dark discoloration and/or they were found on the bottom of test chambers at the test concentration of 125.0, 250.0, 500.0, and 1000.0 mg of a 49% aqueous solution of cyanamide /L during the 96-hour exposure period. The 96-hour LC50 for the rainbow trout was 180.0 mg of a 49% aqueous solution of cyanamide/L (equivalent to 88.2 mg of the pure ai/L). The results indicated a 96-hour NOEC (no observed effect concentration) of 62.5 mg of a 49% aqueous solution of cyanamide/L (equivalent to 30.6 mg of the pure ai/L), which was based on the lack of mortality and abnormal effects.

Reference 3

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1985

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Committee on Methods for Toxicity Tests with Aquatic Organisms (C.E. Stephan, Chairman) (1975). Methods for Acute Toxicity Tests with Fish, Macroinvertebrates and Amphibians. Environmental Protection Agency, Ecological Research Series EPA-660/3-75-009.

Deviations:

yes

Remarks:

, see in the field below

Qualifier:

according to guideline

Guideline:

other: American Public Health Association (1980). Standard Methods for the Examination of Water and Wastewater. 15th ed. Washington, DC. 1134 p.

Deviations:

yes

Remarks:

, see in the field below

Principles of method if other than guideline:

The areas of deviation from the OECD guideline 203 (adopted 1992) are: Analyses of the test solutions were not performed in this study. Though no analyses of the cyanamide concentration in the test media were performed, it can be assumed that the concentration maintained was stable throughout the whole test, as cyanamide is known to be hydrolytically stable. Furthermore, in the algal inhibition test (Doc. No. 823-003) the analyses show that no degradation occurred during the test period, which was 96 hours.

GLP compliance:

yes

Analytical monitoring:

no

Details on sampling:

No sampling

Vehicle:

no

Details on test solutions:

Not indicated

Test organisms (species):

Lepomis macrochirus

Details on test organisms:

Not indicated

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

No post exposure period

Hardness:

Not indicated

Test temperature:

Test solutions were maintained at 22°C

pH:

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges. Analyses of the test solutions were not performed in this study.

Dissolved oxygen:

All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges. Analyses of the test solutions were not performed in this study.

Salinity:

Freshwater

Nominal and measured concentrations:

Treatments consisted of a water control and nominal concentrations of 31.2, 62.5, 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of Cyanamide/L.

Details on test conditions:

The acute toxicity of LH 21.810 (a 49% (w/w) aqueous solution of cyanamide) to unfed juvenile Bluegill sunfish, Lepomis macrochirus, was determined in a static, 96-hour test. Treatments consisted of a water control and nominal concentrations of 31.2, 62.5, 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. Test vessels containing 10 fish each were exposed to each treatment concentration and control. Test solutions were maintained at 22 °C.

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

43.1 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks:

and abnormal effects

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

30.6 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Remarks:

and abnormal effects

Details on results:

There was no mortality below 125.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. The highest concentration causing no mortality was 62.5 mg of a 49% (w/w) aqueous solution of cyanamide/L and the lowest concentration causing 100 % mortality was 125.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. The abnormal effects of loss of equilibrium, fish on the bottom of test chambers and/or quiescence were observed in the 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L test concentrations.

Results with reference substance (positive control):

No positive control

Reported statistics and error estimates:

Not indicated

Sublethal observations / clinical signs:

Mortality of Bluegill sunfish,Lepomis macrochirus, exposed to a 49% (w/w) aqueous solution of cyanamide for 96 hours in an unaerated, static, acute test

Nominal concentrations of the 49% (w/w) aqueous solution of cyanamide (mg/L)	Cumulative mortality (No. dead / No. at test start)
	24 h	48 h	96 h
Water Control	0/10	0/10	0/10
31.2	0/10	0/10	0/10
62.5	0/10	0/10	0/10
125.0	0/10	0/10	10/10
250.0	0/10	0/10	10/10
500.0	5/10	10/10	10/10
1000.0	10/10	10/10	10/10

 

Acute toxicity (96 h) of Cyanamide toLepomis macrochirus–Summary of endpoints:

 

Endpoint	Nominal concentration of 49 % (w/w) aqueous solution of Cyanamide
LC50	88.0 mg/L (43.1 mg as/L)
No observed effect concentration (NOEC)	62.5 mg/L (30.6 mg as/L)

 

Validity criteria fulfilled:

not specified

Conclusions:

The 96-hour LC50 in the Bluegill sunfish was 88.0 mg of a 49% (w/w) aqueous solution of cyanamide/L (equivalent to 43.1 mg as/L, nominal-not measured). The results indicated a 96-hour, NOEC (no observed effect concentration) of 62.5 mg of a 49% (w/w) aqueous solution of cyanamide/L (equivalent to 30.6 mg of the pure as/L), which was based on the lack of mortality and abnormal effects.

Executive summary:

The acute toxicity of LH 21.810 (a 49% (w/w) aqueous solution of cyanamide) to unfed juvenile Bluegill sunfish, Lepomis macrochirus, was determined in a static, 96-hour test. Treatments consisted of a water control and nominal concentrations of 31.2, 62.5, 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. Test vessels containing 10 fish each were exposed to each treatment concentration and control. Test solutions were maintained at 22°C. There was no mortality below 125.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. The highest concentration causing no mortality was 62.5 mg of a 49% (w/w) aqueous solution of cyanamide/L and the lowest concentration causing 100 % mortality was 125.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. The abnormal effects of loss of equilibrium, fish on the bottom of test chambers and/or quiescence were observed in the 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L test concentrations. The 96-hour LC50 in the Bluegill sunfish was 88.0 mg of a 49% (w/w) aqueous solution of cyanamide/L (equivalent to 43.1 mg as/L, nominal-not measured). The results indicated a 96-hour, NOEC (no observed effect concentration) of 62.5 mg of a 49% (w/w) aqueous solution of cyanamide/L (equivalent to 30.6 mg of the pure as/L), which was based on the lack of mortality and abnormal effects.

Reference 4

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPP 72-1 (Fish Acute Toxicity Test)

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Mean measured concentrations of the 49% (w/w) aqueous solution of cyanamide were 61.0, 117.0, 232.0, 476.0, and 1040.0 mg/L and ranged from 93 to 104 % of nominal concentrations. In the test medium the test item was sufficiently stable during the test period of 96 hours.

Vehicle:

no

Details on test solutions:

Treatments consisted of a water control and nominal concentrations of 63.0, 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L.

Test organisms (species):

Cyprinus carpio

Details on test organisms:

Not indicated

Test type:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

96 h

Post exposure observation period:

No post exposure observation period

Hardness:

Not indicated

Test temperature:

22°C

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 63.0, 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L.
Mean measured concentrations of the 49% (w/w) aqueous solution of cyanamide were 61.0, 117.0, 232.0, 476.0, and 1040.0 mg/L .

Details on test conditions:

Test vessels containing 10 fish each

Reference substance (positive control):

no

Key result

Duration:

96 h

Dose descriptor:

LC50

Effect conc.:

80.9 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

mortality (fish)

Key result

Duration:

96 h

Dose descriptor:

NOEC

Effect conc.:

29.9 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

behaviour

Remarks on result:

other: The NOEC concentration, based on mean measured concentrations, was estimated to be 61.0 mg of the 49% aqueous solution of cyanamide/L (equivalent to 29.9 mg as/L).

Details on results:

There were no mortality below 250.0 mg of a 49% (w/w) aqueous solution of cyanamide/L and no sublethal effects below 125.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. The highest concentration causing no mortality was 125.0 mg of a 49% (w/w) aqueous solution of cyanamide/L and the lowest concentration causing 100 % mortality was 250.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. Behavioural/sublethal effects noted during the study included surfacing, erratic swimming, pectoral fins retracted and immobile, fish on bottom of test aquaria, defecating and quiescence. These effects were noted among the fish at test concentration of 125.0, 250.0, and 500.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. Therefore, a no-effect concentration - based on mean measured concentrations - was determined to be 61.0 mg of a 49% (w/w) aqueous solution of cyanamide/L.

Results with reference substance (positive control):

No positive control

Reported statistics and error estimates:

Not indicated

Validity criteria fulfilled:

not specified

Conclusions:

The 96-hour LC50 to Carp was 165.0 mg of the 49% (w/w) aqueous solution of cyanamide/L (equivalent to 80.9 mg as/L). The no-observed effect concentration was estimated to be 61.0 mg of the 49% aqueous solution of cyanamide/L (equivalent to 29.9 mg as/L).

Executive summary:

The acute toxicity of a 49% aqueous solution of cyanamide to unfed juvenile Carp, Cyprinus carpio, was determined in a flow-through, 96-hour test. Treatments consisted of a water control and nominal concentrations of 63.0, 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. Test vessels containing 10 fish each were exposed to each treatment concentration and control. Test solutions were maintained at 22°C. The samples of the test medium were analysed using an UV-VIS Spectrophotometer. Mean measured concentrations of the 49% (w/w) aqueous solution of cyanamide were 61.0, 117.0, 232.0, 476.0, and 1040.0 mg/L and ranged from 93 to 104 % of nominal concentrations. In the test medium the test item was sufficiently stable during the test period of 96 hours. There were no mortality below 250.0 mg of a 49% (w/w) aqueous solution of cyanamide/L and no sublethal effects below 125.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. The highest concentration causing no mortality was 125.0 mg of a 49% (w/w) aqueous solution of cyanamide/L and the lowest concentration causing 100 % mortality was 250.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. Behavioural/sublethal effects noted during the study included surfacing, erratic swimming, pectoral fins retracted and immobile, fish on bottom of test aquaria, defecating and quiescence. These effects were noted among the fish at test concentration of 125.0, 250.0, and 500.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. Therefore, a no-effect concentration - based on mean measured concentrations - was determined to be 61.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. The 96-hour LC50 to Carp was 165.0 mg of the 49% (w/w) aqueous solution of cyanamide/L (equivalent to 80.9 mg as/L). The no-observed effect concentration was estimated to be 61.0 mg of the 49% aqueous solution of cyanamide/L (equivalent to 29.9 mg as/L).

Description of key information

A short term toxicity to fish was examined in four available studies with the test substance cyanamide (49% (w/w) solution of cyanamide).

 

Most of the studies were conducted in a 96 hour static test with different species of unfed freshwater fish. A LC50 of 43.1 as mg/L and a NOEC of 30.6 mg as/L were obtained in the key study with Bluegill sunfish (lepomis macrochirus) fish.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

43.1 mg/L

Additional information

The acute toxicity of cyanamide (49% (w/w) aqueous solution of cyanamide) to fish was examined in four available studies which were conducted in a similar way. The four studies were performed with different fish species, unfed in a static (except for Bowman´s study), 96-hour test. Altogether the key study and the supporting studies exhibited a low toxicity to fish.

 

In the key study (McAllistar, 1985, Doc.No., 821-002) Bluegill sunfish (Lepomis macrochirus) were treated with nominal concentrations of 31.2, 62.5, 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. Test vessels containing 10 fish each were exposed to each treatment concentration and control. There was no mortality below 125.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. The highest concentration causing no mortality was 62.5 mg of a 49% (w/w) aqueous solution of cyanamide/L and the lowest concentration causing 100 % mortality was 125.0 mg of a 49% (w/w) aqueous solution of cyanamide/L. The abnormal effects of loss of equilibrium, fish on the bottom of test chambers and/or quiescence were observed in the 125.0, 250.0, 500.0, and 1000.0 mg of a 49% (w/w) aqueous solution of cyanamide/L test concentrations. The 96-hour LC50 in the Bluegill sunfish was 88.0 mg of a 49% (w/w) aqueous solution of cyanamide/L (equivalent to 43.1 mg as/L, nominal-not measured). The results indicated a 96-hour, NOEC (no observed effect concentration) of 62.5 mg of a 49% (w/w) aqueous solution of cyanamide/L (equivalent to 30.6 mg of the pure as/L), which was based on the lack of mortality and abnormal effects.

 

In another study of McAllistar (1985, Doc.No., 821-001) which was also conducted with Bluegill sunfish (Lepomis macrochirus) a EC50 of 83.2 mg as/L of cyanamide and a similar NOEC to the one of the key study: 30.6 as mg/L cyanamide were obtained.

 

A study conducted in a flow-through conditions with Carp (Cyprinus carpius) fish (Bowman, 1990, Doc. No., 821-003) obtained a LC50 of 80.9 as mg/L and a NOEC of 29.9 as mg/L of cyanamide.

 

In a study conducted with Rainbow trout (Oncorrhynchus mykiss) fish similar results to the key study were obtaine d: EC50 of 45.6 as mg/L and a NOEC of 31.8 as mg/L.