Cyanamide

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

toxicity to microorganisms, other

Remarks:

Growth inhibition

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1988

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: Guideline of the Umweltbundesamt ”Bewertung wassergefährdender Stoffe

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Details on sampling:

No sampling

Vehicle:

no

Details on test solutions:

Not indicated

Test organisms (species):

Pseudomonas putida

Details on inoculum:

Not indicated

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

19 h

Post exposure observation period:

No post exposure observation period

Hardness:

Not indicated

Test temperature:

25°C

pH:

Not indicated

Dissolved oxygen:

Not indicated

Salinity:

freshwater

Nominal and measured concentrations:

100, 180, 320, 561 and 1002 mg/L of 49 % (w/w) aqueous solution of cyanamide. Measured values not available.

Details on test conditions:

In order to determine the percent growth inhibition, at the end of the study the optical density was measured in the nutrient solutions with the 49 % (w/w) aqueous solution of cyanamide and in the control solution without test substance.

Reference substance (positive control):

no

Duration:

19 h

Dose descriptor:

other: TT: toxicity threshold (the concentration of the test substance at which its inhibitory action starts)

Effect conc.:

157 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth inhibition

Key result

Duration:

19 h

Dose descriptor:

EC50

Effect conc.:

283 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth inhibition

Key result

Duration:

19 h

Dose descriptor:

NOEC

Effect conc.:

88 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth inhibition

Details on results:

An inhibition of the growth of Pseudomonas putida was first observed at a concentration of 320 mg/L, where the growth was reduced for 10.3 % in comparison to the control. The highest dose (1002 mg/L) resulted in an inhibition of 90 % .

Results with reference substance (positive control):

No positive control

Reported statistics and error estimates:

Not indicated

Effects of 49% (w/w) aqueous solution of cyanamide on biological methods for sewage treatment:

49% (w/w) aqueous solution of cyanamide (mg/L)	Pure active ingredient cyanamide (mg/L)	Growth inhibition (%)
0	0	-
100	49	0
180	88	0.6
320	157	10.3
561	275	69.1
1002	491	90.0

Validity criteria fulfilled:

not specified

Conclusions:

The toxicity threshold (19 hours) was found to be 320 mg product (49 % (w/w) aqueous solution of cyanamide/L), corresponding to 157 mg as/L. The EC50 (19 hours) was calculated to be 577 mg product/L, corresponding to 283 mg as/L. The NOEC was determined to be 180 mg product/L, corresponding to 88 mg as/L. Therefore, it can be concluded that cyanamide poses a very low risk to biological methods for sewage treatment. Due to its fast dissipation in soil and water, cyanamide is not expected to reach water processing facilities at high concentrations.

Executive summary:

The influence of aqueous hydrogen cyanamide solution on the growth and degradation performance was conducted, using Pseudomonas putida as model organisms in fresh water. A 49 % (w/w) aqueous solution of cyanamide at concentrations of 100, 180, 320, 561 and 1002 mg/L and cultures of Pseudomonas putida were incubated for 19 hours at 25 °C. In order to determine the percent growth inhibition, at the end of the study the optical density was measured in the nutrient solutions with the 49 % (w/w) aqueous solution of cyanamide and in the control solution without test substance.

 

An inhibition of the growth of Pseudomonas putida was first observed at a concentration of 320 mg/L, where the growth was reduced for 10.3 % in comparison to the control. The highest dose (1002 mg/L) resulted in an inhibition of 90 %.

 

The toxicity threshold (19 hours) was found to be 320 mg product (49 % (w/w) aqueous solution of cyanamide/L), corresponding to 157 mg as/L. The EC50 (19 hours) was calculated to be 577 mg product/L, corresponding to 283 mg as/L. The NOEC was determined to be 180 mg product/L, corresponding to 88 mg as/L.

 

Therefore, it can be concluded that cyanamide poses a very low risk to biological methods for sewage treatment.

 

Due to its fast dissipation in soil and water, cyanamide is not expected to reach water processing facilities at high concentrations.

Description of key information

The toxicity of cyanamide to microorganisms was examined in one available study using Pseudomonas putida as model organisms in fresh water. The toxicity threshold (19 hours) was found to be 157 mg ai/L. The EC50 (19 hours) 283 mg as/L. The NOEC was determined to be 180 mg product/L, corresponding to 88 mg as/L. Therefore, it can be concluded that cyanamide poses a very low risk to biological methods for sewage treatment.

Key value for chemical safety assessment

EC50 for microorganisms:

283 mg/L

EC10 or NOEC for microorganisms:

88 mg/L

Additional information

The toxicity of cyanamide (aqueous 49 % (w/w) hydrogen cyanamide solution) to microorganisms was examined in one available study using Pseudomonas putida as model organisms in fresh water. A 49 % (w/w) aqueous solution of cyanamide at concentrations of 100, 180, 320, 561 and 1002 mg/L were applied to cultures of Pseudomonas putida and incubated for 19 hours at 25 °C. In order to determine the percent growth inhibition, at the end of the study the optical density was measured in the nutrient solutions with the 49 % (w/w) aqueous solution of cyanamide and in the control solution without test substance. An inhibition of the growth of Pseudomonas putida was first observed at a concentration of 320 mg/L, where the growth was reduced for 10.3 % in comparison to the control. The highest dose (1002 mg/L) resulted in an inhibition of 90 %.

 

The toxicity threshold (19 hours) was found to be 320 mg product (49 % (w/w) aqueous solution of cyanamide/L), corresponding to 157 mg as/L. The EC50 (19 hours) was calculated to be 577 mg product/L, corresponding to 283 mg as/L. The NOEC was determined to be 180 mg product/L, corresponding to 88 mg as/L.

 

Therefore, it can be concluded that cyanamide poses a very low risk to biological methods for sewage treatment. Due to its fast dissipation in soil and water, cyanamide is not expected to reach water processing facilities at high concentrations.