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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:
July 2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report date:
2003

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Version / remarks:
Adopted June 7, 1984
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Version / remarks:
Dec 1992
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Reference
Name:
Unnamed
Type:
Constituent

Sampling and analysis

Analytical monitoring:
no
Details on sampling:
n.a.

Test solutions

Vehicle:
yes
Remarks:
dilution water
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
A saturated solution ws tested. An appropriate amout of test item was crushed with a mortar. A dispersion (100 mg/L test item was weighed out) was prepared with dilution water one day. prior to application. The stock solution was shaken 20 rpm for 24 h.
- Chemical name of vehicle (organic solvent, emulsifier or dispersant): n.a.
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)): n.a.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): undissolved particles of the test substance were removed by filtration (pore size 0.45 µm)

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Desmodesmus subspicatus
- Strain: CHODAT SAG 86.81
- Source (laboratory, culture collection): Sammlung von Algenkulturen (SAG), University Göttingen, Germany
- Age of inoculum (at test initiation): A four day old preculture was used as inoculum.
- Method of cultivation: Fresh stocks were prepared every month on Z-Agar. Light intensity amounted 35-70 µE/m2 x s for 24 h; nutrient medium Z according to Lüttge et al. (1994)

ACCLIMATION
- Acclimation period: For the start of the test the preculture was diluted with test medium to receive an initial cell concentration of approx. 1 x 10(exp4) cells/mL
- Culturing media and conditions (same as test or not): according to guideline

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Post exposure observation period:
none

Test conditions

Hardness:
NaHCO3: 50 mg/L
Test temperature:
23 +/- 2°C
pH:
8.2 +/- 0.2
Dissolved oxygen:
Not measured
Salinity:
Not measured, freshwater conditions
Nominal and measured concentrations:
A saturated solution was tested. A dispersion (100 mg/L test item was weighed out) was prepared with dilution water one day prior to application. Undissolved particles of the test item were removed by filtration (pore size 0.45 µm)
Details on test conditions:
TEST SYSTEM
- Test vessel: 250 mL Erlenmeyer flasks
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: sterile 250 mL Erlenmeyer flasks, test volume 100 mL
- Aeration: Test containers were placed on a rotary shaker and oscillated at appr. 70 rpm
- Type of flow-through (e.g. peristaltic or proportional diluter): None
- Renewal rate of test solution (frequency/flow rate): One application at test start
- Initial cells density: Nominal: approximately 1 x 10(exp4) cells/mL (measured 11048 cells/mL)
- Control end cells density:
Mean: 964057 cells/mL (test solution); 1068392 cells/mL (control)
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6



GROWTH MEDIUM
- Standard medium used: yes



TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Dilution water, composition acc. to the guideline
- Hardness:
NaHCO3: 50 mg/L
CaCl2x2H2O: 18 mg/L
MgCl2x6H2O: 12 mg/L
- pH-value: 8.15 to 8.79
- Culture medium: Nutrient Medium Z acc. to LÜTTGE et al. (1994)


OTHER TEST CONDITIONS
- Sterile test conditions: no
- Adjustment of pH: no
- Photoperiod: 24 h
- Light intensity and quality: 35 - 70 µE x m-2 x s-1



EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter] fluorimeter, Cell density and self fluorescence was measured daily via Chlorophyll-a- fluorescence, excitation at 435 nm, emission at 685 nm. Dilution water was used as background signal.



TEST CONCENTRATIONS
a saturated solution was tested



Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: saturated solution/saturation concentration; the maximum dissolved concentration of the test item that can be achieved under the test conditions in the test medium according to OECD. 100 mg/L weighed out for preapration of the saturation concentration
Key result
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: saturated solution/saturation concentration; the maximum dissolved concentration of the test item that can be achieved under the test conditions in the test medium according to OECD. 100 mg/L weighed out for preapration of the saturation concentration
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: saturated solution/saturation concentration; the maximum dissolved concentration of the test item that can be achieved under the test conditions in the test medium according to OECD. 100 mg/L weighed out for preapration of the saturation concentration
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: saturated solution/saturation concentration; the maximum dissolved concentration of the test item that can be achieved under the test conditions in the test medium according to OECD. 100 mg/L weighed out for preapration of the saturation concentration
Details on results:
Microscopic evaluation of the cells at the start and end of the incubation period revealed no morphological abnormalitiies.The growth of freshwater green alga Desmodesmus subsoicatus was not inhibited. Water quality parameters of pH-value, measured at 0 and 72 h and room temperature, measured continuously met the guideline requirements.
Results with reference substance (positive control):
EC50 (growth rate): 0.89 mg/L
EC50 (biomass): 0.69 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
In this study the test substance did not cause any effects to the freshwater green alga Desmodesmus subspicatus at the saturated solution.
Executive summary:

The toxicity of the test item to the unicellular freshwater green alga Desmodesmus subspicatus was determined according to OECD guideline 201. The study was conducted under static conditions over a duration of 72 h with an initial cell density of nominally 10(exp4) cells/mL. A saturated solution prepared with 100 mg/L was tested as limit concentration. 3 replicates were tested for the limit concentration and 6 replicates for the control. Microscopic evaluation of the cells at the start and end of the incubation period revealed no morpholaogical abnormalities. Water quality parameters of pH-value measured at 0 and 72 h, and room temperature, measured contiuously, were detemined to be within the acceptable limits. Due to the insolubility of the test item no specific analytical method was available. All effect levels are based on the saturation solution.

- Rate-related inhibition

LOEC > saturation solution

NOEC saturation solution

- Inhibition of biomass growth

LOEC > saturation solution

NOEC saturation solution

The test substance did not cause any effects to the freshwater green alga Desmodesmus subspicatus at the saturated solution.