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Ecotoxicological information

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:
2006/07/27-2006/11/23
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report date:
2006

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
adopted 07 June 1984
Deviations:
yes
Remarks:
For the control, only three replicates were used instead of six as recommended by the Guideline. However, this deviation does not affect the validity of this limit test.
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Version / remarks:
Official Journal No. L 383 A, 29 December 1992
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
1,3-dihydroxyacetone
EC Number:
202-494-5
EC Name:
1,3-dihydroxyacetone
Cas Number:
96-26-4
Molecular formula:
C3H6O3
IUPAC Name:
1,3-dihydroxypropan-2-one
Details on test material:
Dihydroxyacetone

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 100 mg/L (Limit concentration)
- Sampling method: Samples were taken at 0 (start) and 72 h (end) of the experiment
- Sample storage conditions before analysis: Samples were directly analyzed after sampling

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test item (algal medium and test item) was freshly prepared. The test item was weighed into a calibrated flask and filled with algal medium. After stirring of 10 minutes, the test item was completely dissolved and the flask filled to the mark with algal medium.
- Controls: Algal Medium (according to OECD 201)
- Concentration of the test item in the test medium: 100 mg/L

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Desmodesmus subspicatus
- Strain: No. SAG 86.81
- Source (laboratory, culture collection): Sammlung von Algenkulturen, Pflanzenphysiologisches Institut Goettingen, Germany

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h

Test conditions

Hardness:
approx. 0.24 mmol/L (= 25 mg/L CaCO3)
Test temperature:
The test temperature was in the range of 23 - 24°C
pH:
The pH values were in the range of 7.82 - 8.80
Nominal and measured concentrations:
The nominal test item concentration of the test item group was 100 mg/L. HPLC measurements resulted in test item concentrations of 98.4 mg/L (0 hour) and 96.0 mg/L (72 hours), respectively, and, thus, confirmed the correct preparation of the test medium.
Details on test conditions:
TEST SYSTEM
- Test vessel: 300 mL Erlenmeyer flasks (glass)
- Type (delete if not applicable): closed
- Fill volume: 100 mL
- Initial cell density: 10,000 cells/mL
- Control end cells density: 791,451 cells/mL
- No. of vessels per concentration: 3
- No. of vessels per control (replicates): 3

GROWTH MEDIUM
- Standard medium used: yes (algal medium according OECD TG 201)

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: permanent
- Light intensity and quality: 7500 to 9500 Lux by fluorescent tubes (Philips Master Roehren, TL5 80W/840 HO)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: particle counter (Coulter, Z2)

TEST CONCENTRATIONS
- Range finding study: In a pretest inhibition of the grothw rate of D. subspicatus was not observed at a concentration of 100 mg/L
- Test concentrations: 100 mg/L (Limit test)


Results and discussion

Effect concentrationsopen allclose all
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
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
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
- Any stimulation of growth found in any treatment: no

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
validity criteria of OECD 201 are fulfilled
Conclusions:
An aqueous solution of 100 mg/L of the test item revealed no aquatic toxicity in Desmodesmus subspicatus. The 72 hours EC50 was > 100 mg/L (limit test) and, thus, exceeded the limit dose of this test.
Executive summary:

The influence of the test item on the growth and growth rate of the green algae species Desmodesmus subspicatus was tested. The study design included one control and one test material group with three replicates, each containing about 100 mL reconstituted water or test medium and 10,000 cells/mL at the start of the experimental phase. The algae were exposed to a solution of nominal 100 mg/L and the study was performed as a limit test in an open static test system. The growth was calculated after 24, 48, and 72 hours exposure in the test medium.

At the start, the analytically determined concentration was about 98 % of the nominal concentration. At the end of the experimental part, the analytically determined test material concentration was 96 % of the nominal concentration. The test material concentration could be maintained at > 80 % of the initial concentration and, thus, the nominal value was regarded as equivalent to the analytical value. For the test item, the following EC50 values and no effect concentration for Desmodesmus subspicatus were determined:

EbC50 > 100mg/L

ErC50 > 100mg/L

NOEC >= 100mg/L

The data obtained indicate no aquatic toxicity in the test system under the conditions of the experiment.