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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
22/05/1995 - 28/09/1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: RA study
Justification for type of information:
Refer to the section 13 for details on the read across justification.
Reason / purpose:
read-across source
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
- Name of test material (as cited in study report): d,1-a-Tocopheryl Acetate
- Substance type: vitamin derivative
- Physical state: liquid
- Storage condition of test material: at room temperature, in the dark
Analytical monitoring:
yes
Details on sampling:
- Concentrations: nominal concentrations are 5.8, 10, 18, 32, 58 and 100 mg/l
- Sampling method: Composite samples (about 150 ml per concentration and control) of each test concentration were drawn by mixing identical volumes of the test solutions taken from the test vessels. Samples of the test solution were taken immediately before and after 72 hours exposure and stock solution samples were taken 4 hours before exposure.
- Sample storage conditions before analysis: samples were stored at -18 to -22°C util analysis
Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 200.2 mg test substance were mixed with 2 ml; water containing 4 mg Tween 80. This blend were mixed and made up to 2000 ml with reconstituted water by polytron. Calculated amounts of stock solution to produce the desired test concentrations and vehicle to achieve identical vehicle concentration at all test concentrations were given into the water and were homogeneously distributed. The test solutions were equilibrated for 4 hours under test conditions. the algae were then transferred into the flasks.
- Controls: Yes, reconstituted water
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Polyoxyethylen-sorbitan-mono-oleate (Tween 80)
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 2 mg/L
- Evidence of undissolved material (e.g. precipitate, surface film, etc): not relevant
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Selenastrum capricornutum
- Strain: Selenastrum capricornutum 61.81 SAG
- Source (laboratory, culture collection): Collection of algae cultures, Pflanzenphysiologisches Institut University, Göttingen, Germany
- Method of cultivation: according to OECD Guideline 201


ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): same as test
- Any deformed or abnormal cells observed: No
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Hardness:
24 mg CaO/l
Test temperature:
21 - 25 +/- 1 °C
pH:
8.2 - 9.6 with no increase greater than 1.4 during the test.
Nominal and measured concentrations:
Nominal: 5.8, 10, 18, 32, 58 and 100 mg/l
Measured (start): 4.0, 7.0, 11.5, 19.0, 24.0 and 39.8 mg/l
Measured (end): 4.0, 6.5, 9.8, 14.1, 7.6 and 15.7 mg/l
Effect concentrations (based on actual mean concentrations): 4.0, 6.8, 10.7, 16.6, 15.8 and 27.8 mg/l
Details on test conditions:
TEST SYSTEM
- Test vessel: Erlenmeyer flask
- Type (delete if not applicable): closed (cotton stopper)
- Material, size, headspace, fill volume: glass, 100 ml volume (125 ml volume total) with 50 ml medium per flask
- Aeration: No
- Type of flow-through (e.g. peristaltic or proportional diluter): Not applicable, static test
- Renewal rate of test solution (frequency/flow rate): Not applicable, static test
- Initial cells density: 10.400 cells/ml
- Control end cells density: 1.246.000 cells/ml
- No. of organisms per vessel: Not applicable
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): 6


GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used: Not applicable

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Reconstituted water, composition according to guideline
- Conductivity: 160 uS
- Culture medium different from test medium: No
- Intervals of water quality measurement: 72h


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: No
- Photoperiod: continuously
- Light intensity and quality: cold white fluorescent light, 120 uE/m^2 sec +/- 20% (approximately 8000 lux)


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



TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
Reference substance (positive control):
no
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 27.8 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
27.8 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 27.8 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
27.8 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): No
- Unusual cell shape: No
- Colour differences: No
- Flocculation: No
- Adherence to test vessels: No
- Aggregation of algal cells: No
- Other: No
- Effect concentrations exceeding solubility of substance in test medium
Reported statistics and error estimates:
A modified dunnet Multiple Comparison Test was used for calculation of the NOEC.
Exponential growth (>16 x) in controls, variability within limits.
Validity criteria fulfilled:
yes
Conclusions:
Based on the results of the read across study, the 72 h EC50 (growth rate) of the test substance was found to be >27.8 mg/L and the 72 h NOEC (growth rate) was found to be 27.8 mg/L.
Executive summary:

A study was conducted to determine the toxicity of the read across substance to the algae Pseudokirchneriella subcapitata according to OECD Guideline 201, under GLP conditions. Based on the results of the read across study, the 72 h EC50 (growth rate) of the test substance was determined to be >27.8 mg/L and the 72 h NOEC (growth rate) was determined to be 27.8 mg/L (Grade, 1995).

Description of key information

Key value for chemical safety assessment

EC50 for freshwater algae:
27.8 mg/L
EC10 or NOEC for freshwater algae:
27.8 mg/L

Additional information

A study was conducted to determine the toxicity of the read across substance to the algae Pseudokirchneriella subcapitata according to OECD Guideline 201, under GLP conditions. Based on the results of the read across study, the 72 h EC50 (growth rate) of the test substance was determined to be >27.8 mg/L and the 72 h NOEC (growth rate) was determined to be 27.8 mg/L (Grade, 1995).