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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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: The test medium of the highest test concentration of nominal 500 mg/l was prepared. Then, this test medium was serially diluted with test water to obtain the desired test concentrations.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Strain: SAG 86.81
- Source (laboratory, culture collection): Sammlung für Algenkulturen, University of Göttingen
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Test temperature:
23 °C
pH:
7.6 - 9.5
Nominal and measured concentrations:
Nominal test substance concentrations:
3.9, 7.8, 15.63, 31.25, 62.5, 125, 250, 500 mg/l
Details on test conditions:
TEST SYSTEM
- Test vessel: Erlenmeyer vessels (250 ml)
- Fill volume: 100 ml
- Initial cells density: about 10000 cells/ml
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to OECD 201


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Fluorometric measurement of cell density after 0, 24, 48 and 72 hours.
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
42.36 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
123.32 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC90
Effect conc.:
235.05 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Reported statistics and error estimates:
EC50 values were determined with appropriate statistical methods (according to Tallarida & Jacob, 1979).
Conclusions:
The acute toxicity of the substance to aquatic algae was examined in a static test conducted according to OECD guideline 201. Test organisms of the species Desmodesmus subspicatus were exposed to the substance for 72 h. At test termination an ECr50 of 123.32 mg/L (nominal) was determined.

Description of key information

With high probability acutely not harmful to aquatic algae.

Key value for chemical safety assessment

EC50 for freshwater algae:
123.32 mg/L
EC10 or NOEC for freshwater algae:
42.36 mg/L

Additional information

The acute toxicity of the substance to aquatic algae was examined in a static test conducted according to OECD guideline 201. Test organisms of the species Desmodesmus subspicatus were exposed to the substance for 72 h. At test termination an ECr50 of 123.32 mg/L (nominal) was determined.