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Ecotoxicological information

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:
From 11 September 2017 to 29 September 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
Deviations:
yes
Remarks:
The 24h growth rates were not used in the calculation of results.
GLP compliance:
yes (incl. certificate)
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: 278/4
- Source (laboratory, culture collection): SAMS Limited
- Age of inoculum (at test initiation):
- Method of cultivation: culture were prepared from stock laboratory cultures by inoculating autoclaved freshwater at 120 °C for 15 minutes with nutrient medium (3N-BBM+V) 2 to 4 days before test commencement and incubated at approximately 21 2 °C under constant illumination as the inoculum source for subsequent toxicity tests.

ACCLIMATION
- Culturing media and conditions: same as test
- Any deformed or abnormal cells observed: None reported
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Hardness:
Not specified
Test temperature:
21 to 24 °C
pH:
8.1 ±0.2. Not increased during the test by more than 1.5 relative to the pH of the growth medium.
Dissolved oxygen:
Not specified
Salinity:
Not specified
Conductivity:
Not specified
Nominal and measured concentrations:
Nominal concentrations: 1, 10, 100, and 1000 mg/L.
Details on test conditions:
TEST SYSTEM
- Test vessel: borosilicate glass crystallising dishes
- Material, size, headspace, fill volume: 100 mL
- Type of flow-through: static
- Initial cells density: initial cell density of approximately 5 x10^3-10^4 cells per millilitre
- No. of vessels per concentration (replicates): three
- No. of vessels per control (replicates): six

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used: As specified in OECD 201

OTHER TEST CONDITIONS
- Light intensity and quality: Between 5470 and 5490 lx

TEST CONCENTRATIONS
- Test concentrations: 1, 10, 100 and 1,000 mg/L
Reference substance (positive control):
yes
Remarks:
potassium dichromate
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 10 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 10 000 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
5 600 mg/L
Nominal / measured:
nominal
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): None reported
- Unusual cell shape: None reported
- Colour differences: None reported
- Flocculation: None reported
- Adherence to test vessels: None reported
- Aggregation of algal cells: None reported
- Any stimulation of growth found in any treatment: None reported
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: 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: 1.42 mg/L
Reported statistics and error estimates:
Results for both range-finding and definitive tests were calculated by Linear Interpolation within the CETIS suite of statistical analysis.
Validity criteria fulfilled:
yes
Conclusions:
The 72-hour EC50 was >10,000 mg/L and the 72-hour NOEC 5,600 mg/L. The substance did not meet the criteria for classification as toxic to the aquatic environment according to Regulation (EC) N° 1272/2008.
Executive summary:

The short-term toxicity of 1-[(2-hydroxyethyl)thio]propan-2-ol to algae was determined during a GLP-compliant study performed according to the OECD Testing Guideline 201.

The species was Pseudokirchneriella subcapitata.

A range-finding test was performed to determine the concentrations to be used during the definitive test. As a result of this range-finding test, concentrations of 1,000, 1,800, 3,200, 5,600 and 10,000 mg/L were used during the definitive test.

The 72-hour EC50 was >10,000 mg/L and the 72-hour NOEC 5,600 mg/L. The substance did not meet the criteria for classification as toxic to the aquatic environment according to Regulation (EC) N° 1272/2008.

Description of key information

The short-term toxicity of 1-[(2-hydroxyethyl)thio]propan-2-ol to algae was determined during a GLP-compliant study performed according to the OECD Testing Guideline 201.

The species was Pseudokirchneriella subcapitata.

A range-finding test was performed to determine the concentrations to be used during the definitive test. As a result of this range-finding test, concentrations of 1,000, 1,800, 3,200, 5,600 and 10,000 mg/L were used during the definitive test.

The 72-hour EC50 was >10,000 mg/L and the 72-hour NOEC 5,600 mg/L. As a conclusion the test substance was not considered to be toxic to aquatic algae and cyanobacteria.

Key value for chemical safety assessment

EC50 for freshwater algae:
10 000 mg/L

Additional information