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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
09/05/1995 - 22/06/1995
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study according to international standard (OECD guideline 201) performed under GLP, validity criteria met.

Data source

Reference
Reference Type:
other: published parts of study report
Title:
Unnamed
Year:
1995
Report Date:
1995

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid: viscous
Specific details on test material used for the study:
No test surrogate or analogue material was used.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: nominal concentrations were 0, 10, 18, 32, 58 and 100 mg test substance/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 test solutions were taken immediately before exposure and after 72 hours exposure and stock solution (=highest test concentration) was taken 24 hours before and a dark sample after 72h of exposure.
- Sample storage conditions before analysis: stored at 18 - 22°C

Test solutions

Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 200.8 mg test substance were mixed in 800 ml reconstituted water including 4 mg Tween 80 by polytron and then made up to 2000 ml with reconstituted water
- Controls: yes, reconstituted water
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): polyoxyethylen-sorbitan-mono-oleat (Tween 80)
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): 2 mg/l

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: Pseudokirchneriella subcapitata 61.81 SAG (=Selenastrum capricornutum ATCC 22662)
- 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 conditions

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Hardness:
30 mg CaO/l
Test temperature:
24 +/- 1 °C
pH:
8.0 - 8.2 and 9.1-10.0 at the start and end of exposure, respectively.
Nominal and measured concentrations:
Nominal concentrations: 10, 18, 32, 58 and 100 mg/l
Measured concentrations (start): 7.45, 12.50, 19.35, 22.50 and 31.05 mg/l
Measured concentrations (end): 5.30, 8.65, 13.65, 15.10 and 20.55 mg/l
Effect concentrations (based on actual mean concentrations): 6.4, 10.6, 16.5, 18.8 and 25.8 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 (total volume 125 ml), 50 ml medium per test vessel
- Aeration: No
- Initial cells density: 9600 cells/ml
- Control end cells density: 1578000 cells/ml
- No. of organisms per vessel: No data
- 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

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: reconstituted water
- Conductivity: 160 uS
- Culture medium different from test medium: No
- Intervals of water quality measurement: pH measured after 0 and 72 hours


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: No
- Photoperiod: Continuous
- Light intensity and quality: cold white fluorescent light at 120 u E/m^2 +/- 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 cell counter
- Chlorophyll measurement: No

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
Reference substance (positive control):
no

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 25.8 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.:
25.8 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 25.8 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
25.8 mg/L
Nominal / measured:
meas. (geom. mean)
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
- Any stimulation of growth found in any treatment: No
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: No
- Effect concentrations exceeding solubility of substance in test medium: No
Results with reference substance (positive control):
No reference substance was used.
Reported statistics and error estimates:
A modified Dennet Multiple Comparison Test was used for calculation of the NOEC. No error estimates available or 95% confidence intervals are
available.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The 72h EC50 for d,l-a-tocopherol towards Selenastrum capricornutum for growth rate was found to be >25.8 mg/l, 72h NOEC for growth rate
was found to be 25.8 mg/l.
Executive summary:

Toxicty of d,l-a-tocopherol towards Selenastrum capricornutum was determined according to OECD guideline 201 under GLP conditions. The 72h EC50 for growth rate was found to be >25.8 mg/l, 72h NOEC for growth rate was found to be 25.8 mg/l.


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