Cyanamide

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

adult fish: sub(lethal) effects

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 204 (Fish, Prolonged Toxicity Test: 14-day Study)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: U.S. EPA-FIFRA, 40 CFR, Section 158.145, Guideline 72-1.

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

Analytical verification of the aqueous solution of Cyanamide was made on test solutions sampled on days 0, 1, 4, 7, 10, 14 and 21 of the study.

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:

flow-through

Water media type:

freshwater

Limit test:

no

Total exposure duration:

21 d

Post exposure observation period:

No post exposure observation

Hardness:

not indicated

Test temperature:

14 °C - 16 °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 test substance concentrations of 1.9, 3.8, 7.5, 15.0 and 30.0 mg of a 49 % (w/w) aqueous solution of cyanamide/L (equivalent to 0.93, 1.9, 3.7, 7.4 and 15.0 mg as/L).
Mean measured concentrations of the 49 % (w/w) aqueous solution of cyanamide were 1.9, 3.6, 7.5, 15.0 and 30.0 mg/L (equivalent to 0.95, 1.8, 3.7, 7.2 and 15.0 mg as/L) and ranged from 99 ± 2.2 % of nominal concentrations.

Details on test conditions:

Test solutions were supplied to each replicate test chamber by a continuous flow metering system at a rate of approximately 1 L at an average rate of 8.5 times per hour. Test solutions were maintained between 14 and 16 °C. Temperature, dissolved oxygen and pH were measured in the control and in the low, middle and high concentrations on days 0, 1, 4, 7, 10, 14, 18 and 21 of the study. The samples of the test medium were analysed by UV-VIS spectrophotometer. Daily observations were made for behavioural/sublethal effects.

Reference substance (positive control):

no

Key result

Duration:

21 d

Dose descriptor:

LC50

Effect conc.:

11.8 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

mortality

Key result

Duration:

21 d

Dose descriptor:

NOEC

Effect conc.:

3.7 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

other: lack of sublethal effects

Details on results:

Mortality occurred in the 30.0 mg/L treatment. One fish got lost in the 7.5 mg/L treatment in the period between day 18 and 21. One fish in the control chamber was found dead on day 21. This mortality was believed to be an aberration since all fish appeared to be normal on day 20 in this chamber.
Sublethal/behavioural responses (e.g. dark discoloration, laboured respiration, loss of equilibrium, quiescence, fish on bottom of aquaria, flared gills, surfacing and vertical orientation) were noted in the 15 and 30 mg/L test levels

Results with reference substance (positive control):

No positive control

Reported statistics and error estimates:

Not indicated

Long-term toxicity (21 d) of cyanamide to Rainbow trout – Summary of endpoints:

Endpoint	Mean measured concentration of 49 % (w/w) aqueous solution of cyanamide
LC50	24.0 mg/L (11.8 mg as/L)
No observed effect concentration (NOEC)	7.5 mg/L (3.7 mg as/L)

 

Validity criteria fulfilled:

not specified

Conclusions:

In the trout flow-through test the 21 day LC50 was calculated to be 24.0 mg of a 49 % (w/w) aqueous solution of cyanamide/L based on the mean measured concentrations (equivalent to 11.8 mg as/L). The 21-day NOEC was 7.5 mg/L, based on mean measured concentrations and a lack of sublethal effects after 21 days (equivalent to 3.7 mg as/L). The mean measured concentrations are nearly identical to the nominal concentrations.

Executive summary:

The effects of a 49 % (w/w) aqueous solution of cyanamide on Rainbow trout (Oncorhynchus mykiss) were determined under flow-through conditions for 21 days. A water control and nominal test substance concentrations of 1.9, 3.8, 7.5, 15.0 and 30.0 mg of a 49 % (w/w) aqueous solution of cyanamide/L (equivalent to 0.93, 1.9, 3.7, 7.4 and 15.0 mg as/L) were used during the study. A total of 20 trout per concentration were used. Analytical verification of the aqueous solution of cyanamide was made on test solutions sampled on days 0, 1, 4, 7, 10, 14 and 21 of the study. Test solutions were supplied to each replicate test chamber by a continuous flow metering system at a rate of approximately 1 L at an average rate of 8.5 times per hour. Test solutions were maintained between 14 and 16 °C. Temperature, dissolved oxygen and pH were measured in the control and in the low, middle and high concentrations on days 0, 1, 4, 7, 10, 14, 18 and 21 of the study. The samples of the test medium were analysed by UV-VIS spectrophotometer. Daily observations were made for behavioural/sublethal effects. All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges. Mean measured concentrations of the 49 % (w/w) aqueous solution of cyanamide were 1.9, 3.6, 7.5, 15.0 and 30.0 mg/L (equivalent to 0.95, 1.8, 3.7, 7.2 and 15.0 mg as/L) and ranged from 99 ± 2.2 % of nominal concentrations. In the test medium the test item was sufficiently stable during the test period of 21 d. Mortality occurred in the 30.0 mg/L treatment. One fish got lost in the 7.5 mg/L treatment in the period between day 18 and 21. One fish in the control chamber was found dead on day 21. This mortality was believed to be an aberration since all fish appeared to be normal on day 20 in this chamber. Sublethal/behavioural responses (e.g. dark discoloration, laboured respiration, loss of equilibrium, quiescence, fish on bottom of aquaria, flared gills, surfacing and vertical orientation) were noted in the 15 and 30 mg/L test levels. In the trout flow-through test the 21 day LC50 was calculated to be 24.0 mg of a 49 % (w/w) aqueous solution of cyanamide/L based on the mean measured concentrations (equivalent to 11.8 mg as/L). The 21-day NOEC was 7.5 mg/L, based on mean measured concentrations and a lack of sublethal effects after 21 days (equivalent to 3.7 mg as/L). The mean measured concentrations are nearly identical to the nominal concentrations.

Description of key information

The test substance cyanamide (49 % (w/w) aqueous solution of cyanamide) was examined for its long-term toxicity to fish (Rainbow trout (Oncorhynchus mykiss)) in one available study. In this trout flow-through, 21 day test the calculated LC50 was 11.8 mg of pure active ingredient (ai) cyanamide/L and NOEC of 3.7 mg ai/L.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

NOEC

Effect concentration:

3.7 mg/L

Additional information

One experimental study on the long-term toxicity of cyanamide to fish is available and summarized below.

 

The effects of a 49 % (w/w) aqueous solution of cyanamide on Rainbow trout (Oncorhynchus mykiss) were determined in accordance with OECD TG 204 and GLP principles under flow-through conditions for 21 days. A water control and nominal test substance concentrations of 1.9, 3.8, 7.5, 15.0 and 30.0 mg of a 49 % (w/w) aqueous solution of cyanamide/L (equivalent to 0.93, 1.9, 3.7, 7.4 and 15.0 mg as/L) were used during the study. A total of 20 trout per concentration were used. All chemical and physical parameters (dissolved oxygen concentration, pH, temperature) in the definitive test were within expected ranges. Mean measured concentrations of the 49 % (w/w) aqueous solution of cyanamide were 1.9, 3.6, 7.5, 15.0 and 30.0 mg/L (equivalent to 0.95, 1.8, 3.7, 7.2 and 15.0 mg as/L) and ranged from 99 ± 2.2 % of nominal concentrations. In the test medium the test item was sufficiently stable during the test period of 21 d. Mortality occurred in the 30.0 mg/L treatment. One fish got lost in the 7.5 mg/L treatment in the period between day 18 and 21. One fish in the control chamber was found dead on day 21. This mortality was believed to be an aberration since all fish appeared to be normal on day 20 in this chamber. Sublethal/behavioural responses (e.g. dark discoloration, laboured respiration, loss of equilibrium, quiescence, fish on bottom of aquaria, flared gills, surfacing and vertical orientation) were noted in the 15 and 30 mg/L test levels. In the trout flow-through test the 21 day LC50 was calculated to be 24.0 mg of a 49 % (w/w) aqueous solution of cyanamide/L based on the mean measured concentrations (equivalent to 11.8 mg as/L). The 21-day NOEC was 7.5 mg/L, based on mean measured concentrations and a lack of sublethal effects after 21 days (equivalent to 3.7 mg as/L).

 

The test was performed in 1990 according to the then state of internationally accepted scientific methods and GLP principles. The derived NOEC covers an exposure duration of 21 days. Therefore, the test data is considered relevant and acceptable for the assessment of the long-term hazard to fish. Thus, additional long-term testing with fish is regarded scientifically not necessary and not justified with regard to animal welfare.