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Toxicity to aquatic algae and cyanobacteria

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Reference
Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
27.09.2016 – 30.09.2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Experimental test result performed using standard test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Principles of method if other than guideline:
Short term toxicity study was carried out on the growth of aquatic algae and cyanobacteria in accordance with OECD guideline 201.
GLP compliance:
no
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: No data
- Expiration date of the lot/batch: No data
- Purity test date: No data

RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity: No data
- Specific activity: No data
- Locations of the label: No data
- Expiration date of radiochemical substance: No data

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: No data
- Stability under test conditions: No data
- Solubility and stability of the test substance in the solvent/vehicle: No data
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: No data

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: No data
- Preliminary purification step (if any): No data
- Final dilution of a dissolved solid, stock liquid or gel: No data
- Final preparation of a solid: No data

FORM AS APPLIED IN THE TEST (if different from that of starting material) No data

OTHER SPECIFICS: No
Analytical monitoring:
no
Details on sampling:
No data
Vehicle:
yes
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION
The stock solution 200 mg/L was prepared by dissolving transparent liquid in OECD growth medium. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture.

- Controls: OECD medium as specified in OECD 201, used as a control and for dilution of the stock solution.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Strain: 86.81 SAG
- Source (laboratory, culture collection): Institute of botany of the ASCR
- Age of inoculum (at test initiation): 5x103 cells/ml
- Method of cultivation: No data

ACCLIMATION
- Acclimation period: No data
- Culturing media and conditions (same as test or not): No data
- Any deformed or abnormal cells observed: No data
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Remarks on exposure duration:
±1 hour
Post exposure observation period:
No data
Hardness:
No data
Test temperature:
23°C ± 2°C
pH:
The sample at concentration 120 mg/L : pH = 7.9 changed to pH = 7.8 during the test,
Control : pH = 8.2 changed to pH = 7.8 during the test
Dissolved oxygen:
No data
Salinity:
No data
Conductivity:
No data
Nominal and measured concentrations:
0, 2.2, 11, 25, 55 and 120 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: 50ml glass vessel
- Type : closed (with air-permeable stopper)
- Material, size, headspace, fill volume: 7.5 ml
- Aeration: No data
- Type of flow-through (e.g. peristaltic or proportional diluter): No data
- Renewal rate of test solution (frequency/flow rate): No data
- Initial cells density: 5x103 cells/mL
- Control end cells density: No data
- No. of organisms per vessel: No data
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): No data
- No. of vessels per vehicle control (replicates): No data

GROWTH MEDIUM
- Standard medium used: Yes

OTHER TEST CONDITIONS
- Adjustment of pH: Without adjustment
- Photoperiod: Continuous
- Light intensity and quality: 6000 lx - 8000 lx

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell counting: Microscope with counting chamber Cyrus I or electronic particle counter.
- Chlorophyll measurement: No
- Other: ErC50 was calculated using non-linear regression by the software Prism 4.0
Reference substance (positive control):
yes
Remarks:
Potassium dichromate (K2Cr2O7)
Key result
Duration:
72 h
Dose descriptor:
other: ErC50
Effect conc.:
129.3 mg/L
Nominal / measured:
meas. (not specified)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 95% CL: 126.6 – 132.2 mg/L
Details on results:
No data
Results with reference substance (positive control):
- Results with reference substance valid
- ErC50: 0.69 mg/L K2Cr2O7
Reported statistics and error estimates:
ErC50 is calculated from the inhibition of growth rate by non-linear regression using software Prism 4.0, GraphPad.

Control Solution: OECD growth medium without the sample, the coefficient of variation of average growth rate in replicates during the whole test period was 0.8 %.

Validity criteria fulfilled:
yes
Conclusions:
The median effective concentration (ErC50) for the test substance, 3-methoxyacetophenone, in a freshwater algae Desmodesmus subspicatus was determined to be 129.3 mg/L on the basis of effects on growth rate in a 72 hour study.
Executive summary:

Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 3-methoxyacetophenone according to OECD Guideline 201.

The stock solution 200 mg/L was prepared by dissolving transparent liquid in OECD growth medium. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at the concentrations 0, 2.2, 11, 25, 55 and 120 mg/L. Effects on the growth rate of the organism were studied. Study consider as valid as it fulfills all necessary criteria and follows OECD guideline. The median effective concentration (ErC50) for the test substance, 3-methoxyacetophenone, on Desmodesmus subspicatus was determined to be 129.3 mg/L. Based on this ErC50 value and after comparing with CLP criteria for aquatic classification of the substance it is concluded that the substance 3-methoxyaceto phenone does not exhibit toxicity to aquatic algae (Desmodesmus subspicatus) and not classified as per the CLP classification criteria.

Description of key information

Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 3-methoxyacetophenone according to OECD Guideline 201.

The stock solution 200 mg/L was prepared by dissolving transparent liquid in OECD growth medium. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at the concentrations 0, 2.2, 11, 25, 55 and 120 mg/L. Effects on the growth rate of the organism were studied. Study consider as valid as it fulfills all necessary criteria and follows OECD guideline. The median effective concentration (ErC50) for the test substance, 3-methoxyacetophenone, on Desmodesmus subspicatus was determined to be 129.3 mg/L. Based on this ErC50 value and after comparing with CLP criteria for aquatic classification of the substance it is concluded that the substance 3-methoxyaceto phenone does not exhibit toxicity to aquatic algae (Desmodesmus subspicatus) and not classified as per the CLP classification criteria.

Key value for chemical safety assessment

EC50 for freshwater algae:
129.3 mg/L

Additional information

Freshwater algal growth inhibition test was carried out on Desmodesmus subspicatus with the substance 3-methoxyacetophenone according to OECD Guideline 201.

The stock solution 200 mg/L was prepared by dissolving transparent liquid in OECD growth medium. Test solutions of required concentrations were prepared by mixing the stock solution of the test sample with OECD growth medium and inoculum culture and tested at the concentrations 0, 2.2, 11, 25, 55 and 120 mg/L. Effects on the growth rate of the organism were studied. Study consider as valid as it fulfills all necessary criteria and follows OECD guideline. The median effective concentration (ErC50) for the test substance, 3-methoxyacetophenone, on Desmodesmus subspicatus was determined to be 129.3 mg/L. Based on this ErC50 value and after comparing with CLP criteria for aquatic classification of the substance it is concluded that the substance 3-methoxyaceto phenone does not exhibit toxicity to aquatic algae (Desmodesmus subspicatus) and not classified as per the CLP classification criteria.