Retinyl acetate

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:

08/02/1993-07/05/1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study according to international guideline (OECD Guideline 201) under GLP conditions, validity criteria met.

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1993

Report date:

1993

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Retinyl acetate

EC Number:

204-844-2

EC Name:

Retinyl acetate

Cas Number:

127-47-9

Molecular formula:

C22H32O2

IUPAC Name:

(2E,4E,6E,8E)-3,7-dimethyl-9-(2,6,6-trimethylcyclohex-1-en-1-yl)nona-2,4,6,8-tetraen-1-yl acetate

Details on test material:

- Name of test material (as cited in study report): Vitamin A - Acetate
- Physical state: Solid
- Storage condition of test material: At room temperature, in the dark

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not relevant

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Nominal concentrations of 0.205, 0.615, 1.85, 5.5 and 16.5 mg/l
- Sampling method: Composite samples of each test concentration were drawn by mixing identical volumes of the test solutions taken from the approximate center of the test vessels. they were taken immediately before and after 72 hours of exposure.
- Sample storage conditions before analysis: Samples were stored at -18 to -22 degrees celsius before analysis

Test solutions

Vehicle:

yes

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 1.88 g test substance and 1.01 g of a mixture of 96% 1-methyl-2-pyrrolidone (NMP) and 4% Polyoxy-ethylene-sorbitan-monooleate (Tween 80) were mixed together. 50.5 mg of this blend were mixed and made up to 500 ml with water. Calculated amounts of stock solution to produce the desired test concentrations were given into water and were homogeneously distributed. The algae were then transferred into flasks. the test substance was homogeneously distributed in the test vessels at all test times and at test concentrations 0.41 till 3.7 mg/l.
- Controls: Yes
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): 1-methyl-2-pyrrolidone (NMP) and polyoxy-ethylene-sorbitan-monooleate (Tween 80)
- Concentration of vehicle in test medium (stock solution and final test solution(s) including control(s)): NMP: 31.7 mg/l; Tween 80: 1.3 mg/l
- Evidence of undissolved material (e.g. precipitate, surface film, etc): small parts of the test substance were swimming and a deposit was observed at concentrations 11 and 33 mg/l at the end of the exposure.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Common name: Secenesdesmus subspicatus
- Source (laboratory, culture collection): Collection of algae cultures, Pflanzenphysiologisches Institut, Göttingen, Germany
- Method of cultivation: According to OECD Guideline 201


ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): yes

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

No

Test conditions

Hardness:

No data

Test temperature:

23 +/- 1 degrees Celsius

pH:

7.8 - 8.7, no increase greater than 0.8 during test

Dissolved oxygen:

No data

Salinity:

Not relevant

Nominal and measured concentrations:

Nominal: 0.205, 0.615, 1.85, 5.5 and 16.5 mg/l
Measured (start): <0.1, <0.1, <0.1, 0.1 and 0.4 mg/l
Measured (end): <0.1, <0.1, <0.1, <0.1 and <0.1 mg/l

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Type (delete if not applicable): closed (stoppered with aluminum caps)
- Material, size, headspace, fill volume: glass Erlenmeyer flasks of 100 ml, 50 ml test solution per flask
- Aeration: No
- Type of flow-through (e.g. peristaltic or proportional diluter): Not relevant
- Renewal rate of test solution (frequency/flow rate): Not relevant
- Initial cells density: 11.700 cells/ml
- Control end cells density: 1.518.000 cells/ml
- No. of organisms per vessel: Not relevant
- 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 relevant


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: No data
- Total organic carbon: No data
- Particulate matter: No data
- Metals: No data
- Pesticides: No data
- Chlorine: No data
- Alkalinity: No data
- Ca/mg ratio: No data
- Conductivity: No data
- Culture medium different from test medium: no
- Intervals of water quality measurement: No data


OTHER TEST CONDITIONS
- Sterile test conditions: Yes
- Adjustment of pH: No data
- Photoperiod: Continuous illumination
- Light intensity and quality: cold white fluorescent light, 119 uE/m^2 sec +/- 20% (approxiamtely 8000 lux)
- Salinity (for marine algae): Not relevant


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
- Other: No data


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3
- Justification for using less concentrations than requested by guideline: Not relevant
- Range finding study
- Test concentrations: No data
- Results used to determine the conditions for the definitive study: No data

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

0.103 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: nominal 7.5 mg/L, 95% CL: 5.7 - 28.7 mg/l

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.05 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: nominal conc 5.5 mg/L

Details on results:

- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): No data
- Unusual cell shape: No data
- Colour differences: No data
- Flocculation: No data
- Adherence to test vessels: No data
- Aggregation of algal cells: No data
- Other: No data
- Any stimulation of growth found in any treatment: No
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: yes, small parts of the test substances were swimming and a deposit was observed at concentrations 11 and 33 mg/l.
- Effect concentrations exceeding solubility of substance in test medium: Possibly, since deposit and small swimming parts of the test substance were observed at concentrations of 11 and 33 mg/l at the end of the exposure.

Results with reference substance (positive control):

Not relevant

Reported statistics and error estimates:

The EbC-50 values were calculated according to the maximum likelihood method, probit model (Mc Cullag, P., Nelder, J.A., 1983: Generalized linear models, Chapman & Hall, London).

Any other information on results incl. tables

The results are based on the measured average concentration. When the concentration was <0.1, this value divided by a factor 2 was used

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Toxicity of Vitamin A - acetate towards Scenedesmus subspicatus was investigated; the EbC50 was found to be 0.103 mg/l, the EbC0 was found to be 0.05 mg/l.

Executive summary:

Toxicity of Vitamin A - acetate towards Scenedesmus subspicatus was investigated according to OECD Guideline 201, under GLP conditions. The test substance is unstable in water and degrades when exposed to light, therefore it was lost during the test. Furthermore, at higher test concentrations small swimming parts of the test substance and deposit were observed, possibly due to concentrations exceeding water solubility. Toxicity values are based on nominal concentrations. The EbC50 was found to be 0.103 mg/l, the EbC0 was found to be 0.05 mg/l.