Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
72 hours
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Conducted in accordance with current testing guidelines and GLP-compliant.
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes
Analytical monitoring:
no
Details on test solutions:
A sample of MK92K batch SRK 184140C was obtained from Baker Petrolite Corporation's, Kirkby, England facility. MK92K is a clear brown, water-dispersible liquid. Eleven concentrations and a control were used to determine the toxicity of MK92K to Selenastrum capricornutum. The stock concentration was prepared by weight to a precision of 1 mg and diluted to volume in volumetric glassware with deionized water. Each test substance concentration was prepared in triplicate. Six control vessels were prepared with culture medium and inoculum but no test substance. A single concentration series of blanks (media and test substance without inoculum) including a blank control (medium only) were also employed. All test vessels were 250 mL Erlenmeyer flasks containing 50 mL of natural seawater algal assay medium.
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Selenastrum capricornutum
- Strain: Utex # LB1648
- Source (laboratory, culture collection): Stock maintained at the Baker Petrolite Environmental Services Group with the original culture from the Department of Biology's Culture Collection of Algae at the University of Texas at Austin.
- Age of inoculum (at test initiation): 3 ± 1 day old
- Method of cultivation: Stock subcultures were transferred into 250 mL Erlenmeyer flasks containing fresh medium 1 - 2 times per week.
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
20.0 - 21.8°C
pH:
Approximately 8 after equilibration with air
Nominal and measured concentrations:
Nominal concentrations: 0.01, 0.018, 0.032, 0.056, 0.10, 0.18, 0.32, 0.56, 1.0, 1.8 and 3.2 mg/L.
Details on test conditions:
An Eberbach Shaker power unit, located in a Forma walk-in environmental chamber (set at 20°C), was employed and continuously luminated by 6000 - 10,000 lux of light provided by overhead cool-white fluorescent lights. Flasks, 250 mL in size, were randomly placed on the power unit and rotated continuously at 100 ± 5 oscillations per minute. Random placement of the Erlenmeyers was determined using an Excel software program. The flasks were repositioned randomly each day to minimize spatial differences in the chamber. The temperature was measured and recorded at zero, 24, 48 and 72 hours in each of three strategically located temperature control flasks.
Reference substance (positive control):
no
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
0.47 mg/L
Basis for effect:
growth rate
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
0.04 mg/L
Basis for effect:
biomass
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
0.04 mg/L
Basis for effect:
growth rate
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.14 mg/L
Basis for effect:
biomass
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
0.19 mg/L
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
0.16 mg/L
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC90
Effect conc.:
0.94 mg/L
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC90
Effect conc.:
0.89 mg/L
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.01 mg/L
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.02 mg/L
Basis for effect:
growth rate
Validity criteria fulfilled:
yes
Conclusions:
Effective concentration values for MK92K are listed below:

24 Hour EC50 - 0.04 mg/L (Biomass) and 0.04 mg/L (Growth rate)

48 Hour EC50 - 0.14 mg/L (Biomass) and 0.19 mg/L (Growth rate)

72 Hour EC50 - 0.16 mg/L (Biomass) and 0.47 mg/L (Growth rate)
72 Hour EC90 - 0.94 mg/L (Biomass) and 0.89 mg/L (Growth rate)
72 hour NOEC - 0.01 mg/L (Biomass) and 0.02 mg/L (Growth rate)
Executive summary:

Effective concentration values for MK92K are listed below:

24 Hour EC50 - 0.04 mg/L (Biomass) and 0.04 mg/L (Growth rate)

48 Hour EC50 - 0.14 mg/L (Biomass) and 0.19 mg/L (Growth rate)

72 Hour EC50 - 0.16 mg/L (Biomass) and 0.47 mg/L (Growth rate)

72 Hour EC90 - 0.94 mg/L (Biomass) and 0.89 mg/L (Growth rate)

72 Hour NOEC - 0.01 mg/L (Biomass) and 0.02 mg/L (Growth rate)

Description of key information

The acute toxicity of MK92K to freshwater green algae was determined. The EC50 (growth rate) was found to be 0.47 mg/L whilst the NOEC (growth rate) was 0.02 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
0.47 mg/L
EC10 or NOEC for freshwater algae:
0.02 mg/L

Additional information

The acute toxicity of MK92K to freshwater green algae was determined in accordance with OECD Guideline 201 (Alga, Growth Inhibition Test) under static conditions.