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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:
From 6 October, 2017 to18 December, 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
[Specific explanation in addition to field 'Justification for data waiving']

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report Date:
2017

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
Deviations:
no
Principles of method if other than guideline:
- Principle of test:
- Short description of test conditions:
- Parameters analysed / observed:
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material:S17-6-100
- Expiration date of the lot/batch: August 7, 2018
- Purity test date:99.4%

RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity:
- Specific activity:
- Locations of the label:
- Expiration date of radiochemical substance:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material:Room temperature, dark, air-tight, nitrogen-sealed in desiccator
- Stability under test conditions:The spectrum obtained was consistent with that measured before the study, indicating that the test substance was stable under the storage conditions.
- Solubility and stability of the test substance in the solvent/vehicle:Dimethylsulfoxide; >50 g/L Stable
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium:

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing:
- Preliminary purification step (if any):
- Final dilution of a dissolved solid, stock liquid or gel:
- Final preparation of a solid:

FORM AS APPLIED IN THE TEST (if different from that of starting material)

OTHER SPECIFICS:

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 100, 56, 32, 18, 10 mg/L (all test levels)
- Sampling method: Collect 1.0 mL of each test solution from the middle layer of all test vessels and mix (at the beginning of exposure and 72 hours after the beginning of exposure)
- Sample storage conditions before analysis:immediately pretreated

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:Test substance and dilution water (OECD medium) were mixed and stirred for 5 miniutues.to prepare the stock solution of 100 mg/L. The test solution was prepared by diluting the stock solution with dilution water.
- Eluate:
- Differential loading:
- Controls:Dilution water
- Chemical name of vehicle (organic solvent, emulsifier or dispersant):
- Concentration of vehicle in test medium (stock solution and final test solution(s) or suspension(s) including control(s)):
- Evidence of undissolved material (e.g. precipitate, surface film, etc.):

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Unicellular green algae
- Strain: ATCC 22662
- Source (laboratory, culture collection): American Type Culture Collection
- Age of inoculum (at test initiation): 3 days
- Method of cultivation:Algae have been maintained by period subculture using Gorham medium. Algae are kept under sterile condition. Sterile test has been performed periodically, every six months, to confirm that the algae are not contaminated. The algae were precultured under the same conditions as the test culture to prepare the inoculum.

ACCLIMATION
- Acclimation period:
- Culturing media and conditions (same as test or not):same as test
- Any deformed or abnormal cells observed:no

Study design

Test type:
static
Water media type:
freshwater
Remarks:
OECD medium
Limit test:
no
Total exposure duration:
72 h

Test conditions

Test temperature:
21.4-21.8 degree (Celsius)
pH:
7.7-7.9
Nominal and measured concentrations:
Nominal concentrations of 100, 56, 32, 18 and 10 mg/L (90.5, 51.9, 29.1, 16.2 and 9.04 mg/L as measured concentrations)
Details on test conditions:
TEST SYSTEM
- Test vessel:300 mL Erlenmeyer flask with aluminum cap, Iwaki, Asahi Glass Co., Ltd.
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: Volume of the test solution; 100 mL (headspace more than
200 mL)
- Aeration: no
- Type of flow-through (e.g. peristaltic or proportional diluter): no
- Renewal rate of test solution (frequency/flow rate):no
- Initial cells density: 5000 cells/mL
- Control end cells density: 1340000 cells/mL (mean)
- No. of organisms per vessel:5000 cells/mL
- No. of vessels per concentration (replicates):3
- No. of vessels per control (replicates):6
- No. of vessels per vehicle control (replicates):0

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

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:
- Culture medium different from test medium:
- Intervals of water quality measurement:

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH:no
- Photoperiod:Continuous illumination
- Light intensity and quality: 65 to 75μE/m2/s with white fluorescent lamp (on the surface of test culture)
- Salinity (for marine algae):

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: [ electronic particle counter]
- Chlorophyll measurement:no
- Other:

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Justification for using less concentrations than requested by guideline:
- Range finding study
- Test concentrations: Nominal concentrations of 100, 10, 1.0, 0.10 mg/L
- Results used to determine the conditions for the definitive study:Test range
Reference substance (positive control):
not specified
Remarks:
There are periodically reference substance data.

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 90.5 mg/L
Nominal / measured:
meas. (TWA)
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
29.1 mg/L
Nominal / measured:
meas. (TWA)
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):
- Unusual cell shape:no
- Colour differences: no
- Flocculation: no
- Adherence to test vessels: no
- Aggregation of algal cells: no
- Other:
- Any stimulation of growth found in any treatment: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values:no
- Effect concentrations exceeding solubility of substance in test medium:no
Results with reference substance (positive control):
- Results with reference substance valid?
- EC50: 0.771 mg/L (95% confidence limits: 0.754-0.788mg/L, Potassium dichromate)
- Other:

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
ErC50 (0-72h) : >90.5 mg/L, NOECr (0-72h): 29.1 mg/L
Executive summary:

1) Concentrations of test substance in test solutions and test cultures

The time-weighted means of measured concentrations of the test substance in Conc. 1 to 5 were 9.04,16.2,29.1, 51.9 and 90.5 mg/L,respectively,which were more than 80% of the nominal concentration.

2) Inhibition concentration by comparison of growth rates

The results were calculated from the time-weighted mean of measured concentrations.

50% growth inhibition concentration,ErC50 (0-72h) : >90.5 mg/L

(95% confidence limits: not available)*

No observed effect concentration,NOECr (0-72h): 29.1 mg/L

*The highest concentration of the test was 100 mg/L of the maximum test concentration given in the Test Guideline. As the inhibition rate at the highest concentration was less than 50%,the ErC50 value was shown as the range,> maximum concentration".

3) Observation of the appearance of algae

By microscopic observation at the end of exposure,in the concentration groups neither unusual cell shape of algae (contraction,expansion,damaged cell etc.) nor agglutination was observed,and the algae looked normal compared with that in the control group.