Calcium cyanamide

Long-term toxicity to fish

Link to relevant study record(s)

Reference

Reference 1

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

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

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.

Reference 2

Endpoint:

adult fish: sub(lethal) effects

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Upon dissolution in water calcium cyanamide is fast transformed to hydrogen cyanamide.
Therefore, ecotoxicity in natural aquatic environments can be expressed in terms of cyanamide, irrespective of the substance constituting the exposure source. This is supported by experimental results: After stoichiometric correction of test concentrations, toxic effect values of cyanamide and calcium cyanamide are very similar in all standard test organisms. Thus, read-across from cyanamide to calcium cyanamide is justified for aquatic environmental endpoints.
For agricultural applications, calcium cyanamide is formulated as granules (PERLKA) that only slowly dissolve in a soil environment. Exposure of the aquatic environment will be exclusively due to runoff from agricultural fields. As above, cyanamide is the chemical moiety relevant for exposure due to rapid transformation from calcium cyanamide to cyanamide.
(Please note: direct release of the product to surface waters is strictly advised against, thus not a relevant exposure pathway.)
For detailled description where read across is used/recommended and where it is preferrable to refain from read across, please see section 13.2 "read across justification for environmental endpoints" and "Scientific rationale for not using cyanamide as read-across substance for calcium cyanamide on toxicological endpoints"

Reason / purpose for cross-reference:

read-across source

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

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.

Upon dissolution in water calcium cyanamide is fast transformed to hydrogen cyanamide.
Therefore, ecotoxicity in natural aquatic environments can be expressed in terms of cyanamide, irrespective of the substance constituting the exposure source. This is supported by experimental results: After stoichiometric correction of test concentrations, toxic effect values of cyanamide and calcium cyanamide are very similar in all standard test organisms. Thus, read-across from cyanamide to calcium cyanamide is justified for aquatic environmental endpoints.
For agricultural applications, calcium cyanamide is formulated as granules (PERLKA) that only slowly dissolve in a soil environment. Exposure of the aquatic environment will be exclusively due to runoff from agricultural fields. As above, cyanamide is the chemical moiety relevant for exposure due to rapid transformation from calcium cyanamide to cyanamide.
(Please note: direct release of the product to surface waters is strictly advised against, thus not a relevant exposure pathway.)

For detailled description where read across is used/recommended and where it is preferrable to refain from read across, please see section 13.2 "read across justification for environmental endpoints" and "Scientific rationale for not using cyanamide as read-across substance for calcium cyanamide on toxicological endpoints"

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.

This information is used in a read-across approach in the assessment of the target substance.

For detailled description where read across is used/recommended and where it is preferrable to refain from read across, please see section 13.2 "read across justification for environmental endpoints" and "Scientific rationale for not using cyanamide as read-across substance for calcium cyanamide on toxicological endpoints"

Description of key information

In the absence of long-term toxicity studies for fish with calcium cyanamide, available information from the read-across substance cyanamide is used.

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. 

The NOEC of 3.7 mg cyanamide/L carried forward in the risk assessment.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

3.7 mg/L

Additional information

Upon dissolution in water calcium cyanamide is fast transformed to hydrogen cyanamide.

Therefore, ecotoxicity in natural aquatic environments can be expressed in terms of cyanamide, irrespective of the substance constituting the exposure source. This is supported by experimental results: After stoichiometric correction of test concentrations, toxic effect values of cyanamide and calcium cyanamide are very similar in all standard test organisms. Thus, read-across from cyanamide to calcium cyanamide is justified for aquatic environmental endpoints.

For agricultural applications, calcium cyanamide is formulated as granules (PERLKA) that only slowly degrade in a soil environment. Exposure of the aquatic environment will be exclusively due to runoff from agricultural fields. As above, cyanamide is the chemical moiety relevant for exposure due to rapid transformation from calcium cyanamide to cyanamide.

(Please note: direct release of the product to surface waters is strictly advised against, thus not a relevant exposure pathway.)

For detailled description where read across is used/recommended and where it is preferrable to refain from read across, please see section 13.2 "read across justification for environmental endpoints" and "Scientific rationale for not using cyanamide as read-across substance for calcium cyanamide on toxicological endpoints"

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. 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).