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

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
yes
Remarks:
non-critical deviations regarding temperature and pH
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): MOPS-Na (4-Morpholinepropanesulfonic acid, sodium salt)
- Molecular formula (if other than submission substance): -
- Molecular weight (if other than submission substance): -
- Smiles notation (if other than submission substance): -
- InChl (if other than submission substance): -
- Structural formula attached as image file (if other than submission substance): -
- Substance type: salt
- Physical state: solid (powder)
- Analytical purity: > 99.5%
- Impurities (identity and concentrations): -
- Composition of test material, percentage of components: -
- Isomers composition: -
- Purity test date: -
- Lot/batch No.: 061M5449V
- Expiration date of the lot/batch: 30. June 2013
- Radiochemical purity (if radiolabelling): -
- Specific activity (if radiolabelling): -
- Locations of the label (if radiolabelling): -
- Expiration date of radiochemical substance (if radiolabelling): -
- Stability under test conditions: -
- Storage condition of test material: The test item was stored in a closed vessel dark and dry at room temperature.
- Other: -

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 100 mg/L
- Sampling method: - no data
- Sample storage conditions before analysis: - no data

Test solutions

Vehicle:
no

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Desmodesmus subspicatus
- Strain: Chodat
- Source (laboratory, culture collection): MBM Sciencebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen)
- Age of inoculum (at test initiation): -
- Method of cultivation: algae were kept as stock culture on solid agar at 8 °C

ACCLIMATION
- Acclimation period: - 96h
- Culturing media and conditions (same as test or not): -
- Any deformed or abnormal cells observed: - none

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:
no data
Test temperature:
26°C
pH:
8.1 - 10.2
Dissolved oxygen:
no data
Salinity:
no data
Nominal and measured concentrations:
The measured concentrations showed very good correlation with the nominal concentrations. The recovery rate after 72 hours was 96 %.
Therefore the nominal concentration was used for the determination of the results.
Details on test conditions:
TEST SYSTEM
- Test vessel: glass flasks 50 ml
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: -
- Aeration:
- Type of flow-through (e.g. peristaltic or proportional diluter): none
- Renewal rate of test solution (frequency/flow rate): none
- Initial cells density: 18102 cells/ml
- Control end cells density: 3088201 cells/ml
- No. of organisms per vessel:-
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): -

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used: -

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: deionised water

OTHER TEST CONDITIONS
- Sterile test conditions: no data
- Adjustment of pH: no
- Photoperiod: no data
- Light intensity and quality: 4800 Lux
- Salinity (for marine algae):-

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: spectrophotometer
- Chlorophyll measurement: -
- Other: -

TEST CONCENTRATIONS
- Spacing factor for test concentrations: not applicable as limit test
- Justification for using less concentrations than requested by guideline: no toxicity expected
- Range finding study: no
- Test concentrations: 100 mg/l
- Results used to determine the conditions for the definitive study:-
Reference substance (positive control):
yes
Remarks:
potassium dichromate

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
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: area under the growth curve
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
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
biomass
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: area under the growth curve
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): none reported
- Effect concentrations exceeding solubility of substance in test medium: no
Results with reference substance (positive control):
- Results with reference substance valid? YES
- EC50: 1.2 mg/L (ErC50)
- Other: -
Reported statistics and error estimates:
not applicable as no effects were observed

Any other information on results incl. tables

The acute toxicity of MOPS-Na was investigated in a GLP-study according to OECD test guideline 201 using unicellular freshwater green alga Desmodesmus subspicatus.

The study was performed using one concentration containing 100 mg/L with a treatment period of 72 hours. The cell concentration of each replicate was determined by measuring the absorption at 440 nm every 24 hours with a spectral photometer. With these measured values, the number of cells was calculated (linear correlation between cell concentration and absorption given). Then the growth rate µ, the area under the growth curve (AUC1) and the Yield2 were determined.

At the start and at the end of the test, the content of the test item in the test solutions was determined using HPLC. The recovery after 72 hours was 99 % of the start concentration, the measured concentration at the beginning and at the end of the test between 100 % and 99 % of the nominal concentration, respectively.

Therefore, the determination of the results was based on the nominal concentrations.

The EC50s of the positive reference control potassium dichromate were tested in a current reference test. The values lay within the normal range of the laboratory.

As no toxicity was observed, a NOEC (growth rate and biomass) of 100 mg/L and an EC50 (growth rate and biomass) of >100 mg/L were determined for MOPS-Na.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Executive summary:

In a GLP-study according to OECD test guideline 201 MOPS-Na did show no toxicity to algae at the limit test concentration of 100 mg/L. Therefore, MOPS-Na has a NOEC (growth rate and biomass) of 100 mg/L and an EC50 (growth rate and biomass) of >100 mg/L.