[2R[2R*(4R*,8R*)]]-3,4-dihydro-2,8-dimethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol

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

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

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol

EC Number:

233-466-0

EC Name:

3,4-dihydro-2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-2H-benzopyran-6-ol

Cas Number:

10191-41-0

Molecular formula:

C29H50O2

IUPAC Name:

2,5,7,8-tetramethyl-2-(4,8,12-trimethyltridecyl)-3,4-dihydro-2H-1-benzopyran-6-ol

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):

Raphidocelis subcapitata (previous names: Pseudokirchneriella 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 concentrations

Effect concentrations 1

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

Effect concentrations 2

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

Effect concentrations 3

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

Effect concentrations 4

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.