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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1995-08-29 - 1995-09-01
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP-guideline study with analytical monitoring

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
according to guideline
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
Cas Number:
Molecular formula:
C22 H8 Cl4 F6 N8 S2
Details on test material:
- Name of test material (as cited in study report): MB 046307
- Physical state: yellow powder
- Analytical purity: 972 g/kg
- Lot No.: 95-4023
- Storage condition of test material: in the dark at room temperature (ca. 20 °C)

Sampling and analysis

Analytical monitoring:
Details on sampling:
- Sampling method: Samples of test solutions were taken for analysis from each bulk preparation at test initiation (0 hour) and from pooled test solutions at test termination (72 hours). Each sample volume was 50 mI and was collected from the approximate midpoint of the container. Samples were taken in duplicate. AIl samples were prepared immediately after sampling and either analyzed within 24 hours after preparation or appropriately preserved and stored until analysis.

Test solutions

Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Stock solution: A stock solution of the highest test substance concentration was prepared by dissolution of 40 mg of MB 046307 in 2 ml of DMF (Dimethyl formamide). Stock solutions of the four lowest test substance concentrations were then prepared by serial dilution of the first stock solution in DMF. Bulk volumes for each of the test solutions were prepared by diluting with dilution water. Each bulk preparation was submitted to magnetic agitation for homogenization. Algal inoculum was subsequently added to each bulk preparation to give final volumes of approximately 400 mI per treatment level and solvent control and 700 ml for the dilution water control.
- Test solutions: Treatment replicate vessels were filled from bulk preparation to 100 ml each.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): Dimethyl formamide (DMF)

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
- Strain: 86.81 SAG
- Source (laboratory, culture collection): Collection of the University of Göttingen, Germany. Cultured by the laboratory of the Aquatic Ecotoxicity testing facilities, Rhône-Poulenc Agrochimie, Centre de Recherche, Sophia Antipolis, France.
- Age of inoculum (at test initiation): The algal cells used for the test cultures were taken from a preculture which was initiated 96 hours prior to the test under the same conditions as in the test.

- Culturing media and conditions: Same as test. The culturing medum was a diluted nutrient concentrate. Algae were cultured in glass vessels of 500 ml containing ca. 300 ml of culture solution. The vessels were fitted with stainless steel caps. The cultures were maintained in an air conditioned culture room at a temperature of 23°C ± 2°C and transfers were made regularly into fresh sterile media.
- Photoperiod: 16 hours light and 8 hours darkness
- Light inensity: Approximately 1 000 Lux
- Agitation: Manual agitation at least once per working day

Study design

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

Test conditions

Test temperature:
Study initiation: 24.4 - 24.8 °C
Study end: 22.9 - 23.2 °C
Study initation: 7.4 - 7.5
Study end: 7.5 - 8.1
Nominal and measured concentrations:
Nominal test concentrations: control, 0.09, 0.19, 0.41, 0.91, 2.0 mg/L
Mean measured concentrations: < 0.01, 0.04, 0.12, 0.28, 0.65, 1.5 mg/L
Details on test conditions:
- Test vessel:
- Material, fill volume: Erlenmayer flasks fitted with stainless steel caps which permitted gas exchange. Each test vessel contained 100 ml of test solution.
- Initial cells density: 17500 - 22500 cells/ml
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 3
- No. of vessels per vehicle control (replicates): 6

- Culture medium different from test medium: no
- Intervals of water quality measurement: 0, 72 h

- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: artificial illumination, 8000 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Cell counts were performed using a Malassez haemocytometer and a microscope

- Spacing factor for test concentrations: 2.2
- Range finding study
- Test concentrations: 0.02, 0.2 and 2.0 mg/l, a solvent control and a dilution water control (two replicates for each group).
- Results used to determine the conditions for the definitive study: No significant growth inhibition percentage was observed at any of the test concentrations showing the EC50 values of MB 046307 to be above the visual limit of aqueous solubility.

Results and discussion

Effect concentrationsopen allclose all
72 h
Dose descriptor:
Effect conc.:
> 1.5 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: the loading of 1.5 mg/L is in excess of the visual limit of aqueous solubility
72 h
Dose descriptor:
Effect conc.:
> 1.5 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
Remarks on result:
other: the loading of 1.5 mg/L is in excess of the visual limit of aqueous solubility
Details on results:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: Concentrations over 0.41 mg/L were above the visual limit of aqueous solubility. This was defined by the presence of undissolved particles in these test solutions at test initiation.
- Effect concentrations exceeding solubility of substance in test medium: yes

Applicant's summary and conclusion