Cyanogen bromide

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Cyanogen bromide

EC Number:

208-051-2

EC Name:

Cyanogen bromide

Cas Number:

506-68-3

Molecular formula:

CBrN

IUPAC Name:

cyanogen bromide

Test material form:

solid: particulate/powder

Test organisms

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name:
- Strain:
- Source (laboratory, culture collection): Culture maintained in BRF, India
- Age of inoculum (at test initiation):
- Method of cultivation:

ACCLIMATION
- Acclimation period:
- Culturing media and conditions (same as test or not):
- Any deformed or abnormal cells observed:

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Test conditions

pH:

Range Finding
0 h : Control: 8.10
Treatment: 7.63 – 7.87
72 h : Control: 8.10
Treatment: 7.47 – 7.83
Main Study
0 h : Control: 8.10
Treatment: 7.70 – 7.97
72 h : Control: 8.10
Treatment: 7.63 – 7.97

Details on test conditions:

TEST SYSTEM
- Test vessel: Conical flask

- Material, size, headspace, fill volume: 250 mL


- Initial cells density: >5×104 cells/ml

- No. of organisms per vessel:
- No. of vessels per concentration (replicates): 3 replications/ Concentrations
- No. of vessels per control (replicates):
- No. of vessels per vehicle control (replicates):

GROWTH MEDIUM
- Standard medium used: yes/no
- Detailed composition if non-standard medium was used:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:
- Culture medium different from test medium:
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH:
- Photoperiod:
- Light intensity and quality:
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]
- Chlorophyll measurement:
- Other:

TEST CONCENTRATIONS
- Spacing factor for test concentrations:
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations:
- Results used to determine the conditions for the definitive study:

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

ca. 0.708 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

not specified

Basis for effect:

other: probit analysis method

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on the growth rate inhibition (%) result, the EC50 value of Cyanogen Bromide for 72 hour period was 0.708 mg/l (Lower Limit 0.512 – Upper Limit 0.904) by using Probit analysis method.

Executive summary:

Growth inhibition effect of Cyanogen Bromide Sponsored by Libor Bachura vyzkum a vyroba was tested againstPseudokirchneriella subcapitataat Bioscience Research Foundation, India by following OECD guideline No. 201, Adopted 23 March 2006.

Solubility and Stability Analysis

The test substance 100 mg wasdissolved in 1000 ml of exposure medium and found that it was soluble. Hence exposure medium was used as control. The test substance was stable in the exposure medium for 72 hours. Hence the study was conducted as static test.

Range Finding Study

Prior to exposure for the range finding study the preculture was maintained for 3 days in test condition. The initial cell concentration of 5x10³- 5x10⁴cells/ml was inoculated to control and treatment of the OECD 201 medium. The cells were counted at 24, 48 and 72 h after exposure period by using haemocytometer under the microscope.During the study,the pH of the medium was between pH 7.47 - 8.10.

A range finding study was conducted with control, 0.1, 1, 10, 50 and 100 mg/l concentration. On the day of exposure the initial average pH of the medium was 8.10, 7.87, 7.83, 7.73, 7.67 and 7.63 recorded in control, 0.1, 1, 10, 50 and 100 mg/l concentration respectively.

At the end of 24 hour observation, the average specific growth rate of the control and treatment was 5.95, 4.58, 4.18, 1.87, 1.99 and 1.23recorded in control,0.1, 1, 10, 50 and 100 mg/lconcentrationrespectively. At the end of 48 hour observation, the average specific growth rate was 6.36, 5.12, 5.29, 2.15, 2.08 and 1.54 recorded in control, 0.1, 1, 10, 50 and 100 mg/lconcentrationrespectively. At the end of 72 hour observation, the average specific growth rate was 7.27, 6.75, 5.02, 1.78, 0.00 and 0.00 recorded in control, 0.1, 1, 10, 50 and 100 mg/l concentration respectively. At the end of experimental period 0-3 day, the average specific growth rate was 2.42, 2.25, 1.67, 0.59, 0.00 and 0.00 in control, 0.1, 1, 10, 50 and 100 mg/l concentration per day.

At the end of 24 hour observation, the percentage of growth inhibition was 23.09%, 29.80%, 68.65%, 66.56% and 79.34% observed in 0.1, 1, 10, 50 and 100 mg/l concentration respectively. At the end of 48 hour observation, 19.53%, 16.87%, 66.22%, 67.23% and 75.87% of growth inhibition was observed in exposed concentrations of 0.1, 1, 10, 50 and 100 mg/l concentration respectively. At the end of 72 hour observation, 7.14%, 31.00%, 75.48%, 100.00% and 100.00% of growth inhibition was observed in exposed concentration of 0.1, 1, 10, 50 and 100 mg/l concentration respectively. The percentage of growth inhibition on 0-3^rdday was 7.14%, 31.00%, 75.48%, 100.00% and 100.00% observed in exposed concentrations of 0.1, 1, 10, 50 and 100 mg/l concentration respectively.

At the end of 0 – 3 day 40.50%, 89.53%, 99.65%, 100.00% and 100.00% yield reduction was observed in 0.1, 1, 10, 50 and 100 mg/l exposed concentration respectively. The final day average pH of the medium was 8.10, 7.83, 7.73, 7.67, 7.60 and 7.47 in control, 0.1, 1, 10, 50 and 100 mg/l exposed concentration respectively.

Main Study

Based on the results of range finding study, main study was conducted with control and five different concentrations of0.0625, 0.125, 0.25, 0.5 and 1mg/l concentrations. On the day of exposure the initial average pH of medium was 8.10, 7.97, 7.90, 7.77, 7.73 and 7.70 recorded in control, 0.0625, 0.125, 0.25, 0.5 and 1 mg/l exposed concentration respectively.

At the end of 24 hour observation, average specific growth rate was 6.07, 5.30, 4.81, 4.59, 4.18 and 4.04recorded in control, 0.0625, 0.125, 0.25, 0.5 and 1 mg/l concentrationrespectively. At the end of 48 hour observation, the average specific growth rate was 6.29, 5.27, 4.65, 4.56, 4.45 and 3.29 observed incontrol, 0.0625, 0.125, 0.25, 0.5 and 1 mg/l exposed concentrationrespectively. At the end of 72 hour observation, the average specific growth rate was 6.70, 4.90, 4.78, 4.20, 4.18 and 2.62 recorded incontrol, 0.0625, 0.125, 0.25, 0.5 and 1 mg/lconcentration of exposed test substance respectively. At the end of experimental period, 0-3 day, the average specific growth rate was 2.23, 1.63, 1.59, 1.40, 1.39 and 0.87 incontrol, 0.0625, 0.125, 0.25, 0.5 and 1 mg/lconcentration respectively.

At the end of 24 hour observation, the percentage of growth inhibition was 12.78, 20.85, 24.49, 31.09 and 33.44% observed in0.0625, 0.125, 0.25, 0.5 and 1mg/l concentration respectively. At the end of 48 hour observation, 16.21, 26.14, 27.54, 29.25 and 47.75% of growth inhibition was observed in exposed concentrations of0.0625, 0.125, 0.25, 0.5 and 1mg/l concentration respectively. At the end of 72 hour observation, 26.89, 28.66, 37.32, 37.67 and 53.01% of growth inhibition was observed in exposed concentration of0.0625, 0.125, 0.25, 0.5 and 1mg/l concentration respectively. The percentage of growth inhibition on 0-3^rdday was 26.89, 28.66, 37.32, 37.67 and 60.93% observed in exposed concentrations of0.0625, 0.125, 0.25, 0.5 and 1mg/l concentration respectively.

At the end of 0 – 3 day, 83.50%, 85.34%, 91.91%, 92.08% and 98.40% yield reduction was observed in0.0625, 0.125, 0.25, 0.5 and 1mg/l in exposed concentration of the test substance respectively. The final day average pH of the medium was 8.10, 7.97, 7.80, 7.73, 7.67 and 7.63 recorded in control,0.0625, 0.125, 0.25, 0.5 and 1mg/l exposed concentration respectively.

Coefficient variation (%)                              

The coefficient variation of the control culture were 0.00, 0.59, 0.95 and 0.39 for 0-1, 1-2, 2-3 and 0-3 day respectively section by section within the stipulated limit as per OECD 201.

Effective concentration for growth inhibition %

Based on the result of growth rate inhibition (%), the EC₅₀value was 0.708 mg/l (Lower Limit 0.512 – Upper Limit 0.904) forCyanogen Bromideon alga.