Cyanamide

Sediment toxicity

Link to relevant study record(s)

Reference

Endpoint:

sediment toxicity: long-term

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000-12-21 until 2001-06-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Streloke & Köpp (1995): Long-term toxicity test with Chironomus riparius: Development and validation of a new test system.

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 219 (Sediment-Water Chironomid Toxicity Test Using Spiked Water)

Version / remarks:

Draft version, February 2000

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The concentration of cyanamide in overlying water, sediment pore water and wet sediment was determined 0, 7 and 28 days after application.

Vehicle:

no

Test organisms (species):

Chironomus riparius

Details on test organisms:

25 larvae of the first larval stage (2 - 3 days old)

Study type:

laboratory study

Test type:

static

Water media type:

freshwater

Type of sediment:

artificial sediment

Limit test:

no

Duration:

28 d

Exposure phase:

total exposure duration

Post exposure observation period:

No post exposure observation period

Hardness:

Water used throughout the study was Elendt M4 Medium (high-hardness media)

Test temperature:

Not indicated

pH:

pH 6.0

Dissolved oxygen:

Not indicated

Salinity:

Freshwater

Ammonia:

Artificial sediment batch: 0.6 mg/ 100 g
Water < 0.02 mg / L

Conductivity:

Not specified

Nominal and measured concentrations:

Treatments consisted of a water control, 3.0, 5.0, 8.0, 13.0, 22.0, 36.0, 60.0 and 100.0 mg of the 51 % (w/w) aqueous solution of cyanamide/L, corresponding to 1.53, 2.56, 4.1, 6.64, 11.24, 18.4, 30.66 and 51.1 mg as/L.
Mean measured concentrations of cyanamide in overlying water at day 0 were 1.75, 13.8 and 46.2 mg/L for the test vessels of 3.0, 22.0 and 100.0 mg of the 51 % (w/w) aqueous solution of cyanamide/L, corresponding to 0.89, 7.05 and 23.60 mg ai/L and ranged from 89 to 125 % of nominal concentrations.
Mean measured concentrations of cyanamide in pore water at day 0 were 0.59, 1.75 and 1.74 mg/L for the test vessels of 3.0, 22.0 and 100.0 mg of the 51 % (w/w) aqueous solution of cyanamide/L in the water phase and ranged from 3 to 45 % of nominal concentrations. This values correspond to 0.30, 0.89 and 0.88 mg ai/L.
Mean measured concentrations of cyanamide in sediment at day 0 were below the limit of quantification (LOQ = 0.411 mg/kg) for the test vessels of 3.0 and 22.0 mg of the 51 % (w/w) aqueous solution of cyanamide/L in the water-phase and 1.0 mg/kg for the highest test concentration level.

Details on test conditions:

The test organisms were fed during the study and the study was conducted under static conditions. Artificial sediment that consisted of 10 % sphagnum peat, 20 % kaolin clay and 70 % industrial sand and adjusted to pH 6.0 was used as a substrate. Water used throughout the study was Elendt M4 Medium. Test vessels (2 L glass-beakers) containing a 2 cm layer of sediment and 15 cm of overlying water were prepared and allowed to acclimate 7 days before use. 25 larvae of the first larval stage (2 - 3 days old) were added to each vessel 24 hours prior to treatment.

Four replicates were used for each treatment. At test start, the aqueous solution of cyanamide was applied just below the water surface of the test vessels by using a pipette and gently mixed without disturbing the sediment.

Reference substance (positive control):

no

Key result

Duration:

28 d

Dose descriptor:

EC50

Effect conc.:

28.97 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

18.39 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

30.66 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

emergence rate

Key result

Duration:

28 d

Dose descriptor:

NOEC

Effect conc.:

6.64 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

development rate

Duration:

28 d

Dose descriptor:

LOEC

Effect conc.:

11.24 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

development rate

Details on results:

After 28 days, the emergence in the water control was 87 %. The emergence was not significantly inhibited up to 36.0 mg of the 51 % aqueous solution of cyanamide/L. At the highest test concentration the inhibition of emergence was 98 %. The calculated emergence ratio was not significantly reduced at treatment concentrations at or below 36.0 mg of the 51 % aqueous solution of cyanamide/L.

The development rate as an indicator of an emergence delay was not significantly reduced at treatment concentrations of 13.0 mg of the 51 % aqueous solution of cyanamide/L and below. Only one of the test vessels of the 22.0 mg/L test concentration level indicate a significant difference in number of male to number of female. Due to the fact that at higher test concentrations no respective effect was observed, no concentration effect relationship was found. Therefore, the calculation of the toxicological endpoints was performed with the pooled number of male and female midges.

Results with reference substance (positive control):

No positive control

Reported statistics and error estimates:

Not indicated

Analysis of cyanamide in overlying water: The results indicated that cyanamide decreased with time in the overlying water for the test vessels of 3.0 and 22.0 mg of the 51 % (w/w) aqueous solution of cyanamide/L. After 7 days only about the half of the initial concentration was found. After 28 days the cyanamide concentration was found below the limit of quantification. For the highest concentration level the decrease started after the 7th day of exposure and even at 28th day of exposure cyanamide was found above the limit of quantification. The active substance cyanamide was degraded to 3.3 % of the initial nominal concentration at the highest test concentration and to less than 1 % of the initial nominal concentration at the lower concentration levels.

 

Analysis of cyanamide in pore water: With a latency of 7 days at the highest concentration level the results indicated that cyanamide decreased with time in the pore water.

Analysis of cyanamide in sediment: Less than 0.5 % of cyanamide was transferred to the sediment.

 

Analytical determination of concentrations tested in the water phase:

Nominal concentrations of the 51 % (w/w) aqueous solution of cyanamide (mg/L)	Mean measured test concentrations (mg/L) of samples taken after
	0 d	7 d	28 d
Water control	< LOQ	< LOQ	< LOQ
3.0	1.75	0.69	< LOQ
22.0	13.8	8.20	< LOQ
100.0	46.2	57.7	1.0

 

 

Analytical determination of concentrations tested in the pore water:

Nominal concentrations of the 51 % (w/w) aqueous solution of cyanamide (mg/L)	Mean measured test concentrations (mg/L) of samples taken after
	0 d	7 d	28 d
Water control	< LOQ	< LOQ	< LOQ
3.0	0.59	< LOQ	< LOQ
22.0	1.75	0.65	< LOQ
100.0	1.74	5.07	< LOQ

 

 

Analytical determination of concentrations tested in the sediment:

Nominal concentrations of the 51 % (w/w) aqueous solution of cyanamide (mg/L)	Mean measured test concentrations (mg/L) of samples taken after
	0 d	7 d	28 d
Water control	< LOQ	< LOQ	< LOQ
3.0	< LOQ	< LOQ	< LOQ
22.0	< LOQ	< LOQ	< LOQ
100.0	1.0	< LOQ	< LOQ

 

 

Nominal concentrations of the 51 % (w/w) aqueous solution of cyanamide (mg/L)	Mean emergence (%)	Mean development rate (%)	Males – number of emerging adults	Females – number of emerging adults
Water control	87.0	0.0629	40	47
3.0	84.0	0.0646	38	46
5.0	98.0	0.0608	38	61
8.0	78.0	0.0643	36	42
13.0	85.0	0.0624	48	40
22.0	96.0	0.0562	27	69
36.0	84.0	0.0550	36	48
60.0	37.0	0.0502	19	18
100.0	2.0	0.0457	1	1

No chironomids emerged before day 14

 

Validity criteria fulfilled:

yes

Conclusions:

In a study according to OECD TG 219 with C. riparius the EC50 (28d) based on emergence inhibition was determined to be 56.7 mg of a 51 % (w/w) aqueous solution of cyanamide/L (28.97 mg a.i./L).

Executive summary:

The effect of a 51 % (w/w) aqueous solution of cyanamide on Chironomus riparius was determined in an aerated, 28-day emergence test which was conducted in a similar was to the OECD 219. 25 larvae of the first larval stage (2 - 3 days old) were added to each vessel 24 hours prior to treatment. Treatments consisted of a water control, 3.0, 5.0, 8.0, 13.0, 22.0, 36.0, 60.0 and 100.0 mg of the 51 % (w/w) aqueous solution of cyanamide/L, corresponding to 1.53, 2.56, 4.1, 6.64, 11.24, 18.4, 30.66 and 51.1 mg as/L. Four replicates were used for each treatment. Analysis of cyanamide was performed in overlying water, in pore water and in sediment. After 28 days, the emergence in the water control was 87 %. The emergence was not significantly inhibited up to 36.0 mg of the 51 % aqueous solution of cyanamide/L. At the highest test concentration the inhibition of emergence was 98 %. The calculated emergence ratio was not significantly reduced at treatment concentrations at or below 36.0 mg of the 51 % aqueous solution of cyanamide/L. The development rate as an indicator of an emergence delay was not significantly reduced at treatment concentrations of 13.0 mg of the 51 % aqueous solution of cyanamide/L and below. Only one of the test vessels of the 22.0 mg/L test concentration level indicate a significant difference in number of male to number of female. Due to the fact that at higher test concentrations no respective effect was observed, no concentration effect relationship was found. Therefore, the calculation of the toxicological endpoints was performed with the pooled number of male and female midges.

 

Based on nominal initial overlying water concentrations, the ecotoxicological endpoints for Chironomus riparius for the 51 % (w/w) aqueous solution of cyanamide were as follows: Emergence inhibition: EC50 (28d) = 56.7 mg of a 51 % (w/w) aqueous solution of cyanamide/L (28.97 mg ai/L) and a corresponding NOEC (28d) = 36.0 mg of a 51 % (w/w) aqueous solution of cyanamide/L (18.39 mg ai/L) LOEC (28d) = 60.0 mg of a 51 % (w/w) aqueous solution of cyanamide/L (30.66 mg ai/L)

 

Development rate: NOEC (28d) = 13.0 mg of a 51 % (w/w) aqueous solution of cyanamide/L (6.64 mg ai/L), LOEC (28d) = 22.0 mg of a 51 % (w/w) aqueous solution of cyanamide/L (11.24 mg ai/L).

Description of key information

Long-term toxicity to sediment dwelling organisms was tested in a study performed in Chironous sp. according to OECD Guideline 219 (Draft February 2000). Based on the results a NOEC of 6.64 mg/L was determined.

Additional information

The effect of a 51 % (w/w) aqueous solution of cyanamide on Chironomus riparius was determined in an aerated, 28-day emergence test which was conducted in a similar was to the OECD 219. 25 larvae of the first larval stage (2 - 3 days old) were added to each vessel 24 hours prior to treatment. Treatments consisted of a water control, 3.0, 5.0, 8.0, 13.0, 22.0, 36.0, 60.0 and 100.0 mg of the 51 % (w/w) aqueous solution of cyanamide/L, corresponding to 1.53, 2.56, 4.1, 6.64, 11.24, 18.4, 30.66 and 51.1 mg as/L. Four replicates were used for each treatment. Analysis of cyanamide was performed in overlying water, in pore water and in sediment. After 28 days, the emergence in the water control was 87 %. The emergence was not significantly inhibited up to 36.0 mg of the 51 % aqueous solution of cyanamide/L. At the highest test concentration the inhibition of emergence was 98 %. The calculated emergence ratio was not significantly reduced at treatment concentrations at or below 36.0 mg of the 51 % aqueous solution of cyanamide/L. The development rate as an indicator of an emergence delay was not significantly reduced at treatment concentrations of 13.0 mg of the 51 % aqueous solution of cyanamide/L and below. Only one of the test vessels of the 22.0 mg/L test concentration level indicate a significant difference in number of male to number of female. Due to the fact that at higher test concentrations no respective effect was observed, no concentration effect relationship was found. Therefore, the calculation of the toxicological endpoints was performed with the pooled number of male and female midges.

 

Based on nominal initial overlying water concentrations, the ecotoxicological endpoints for Chironomus riparius for the 51 % (w/w) aqueous solution of cyanamide were as follows: the EC50 (28d) based on emergence rate was 56.7 mg of a 51 % (w/w) aqueous solution of cyanamide/L (28.97 mg ai/L) and the corresponding NOEC (28d) was 36.0 mg of a 51 % (w/w) aqueous solution of cyanamide/L (18.39 mg ai/L) LOEC (28d) = 60.0 mg of a 51 % (w/w) aqueous solution of cyanamide/L (30.66 mg ai/L).

 

Development rate: NOEC (28d) = 13.0 mg of a 51 % (w/w) aqueous solution of cyanamide/L (6.64 mg ai/L), LOEC (28d) = 22.0 mg of a 51 % (w/w) aqueous solution of cyanamide/L (11.24 mg ai/L).