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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Link to relevant study record(s)

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 with acceptable restrictions
Remarks:
Analytical verification of test concentrations not conducted for the algal study
Qualifier:
according to
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
GLP compliance:
not specified
Remarks:
Published study from a peer-reviewed journal.
Analytical monitoring:
no
Remarks:
No analytical verification of concentrations in algal study.
Vehicle:
yes
Remarks:
Ethanol
Details on test solutions:
Control: Dilution water
Solvent Control: Ethanol, maximum of 0.05% in test medium
Solvent concentration in test solutions was set to a maximum of 0.05% in the test medium for all tests
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
Source: ECT Oekotoxikologie GmbH, Floersheim, Germany.
Test type:
static
Water media type:
freshwater
Remarks:
AAP algal medium
Limit test:
no
Total exposure duration:
72 h
Hardness:
Not reported
Test temperature:
20.5 ± 1 deg C
pH:
Not reported
Dissolved oxygen:
Not reported
Salinity:
Not applicable
Conductivity:
Not reported
Nominal and measured concentrations:
Nominal test concentrations: 0.5. 1.0. 2.0, 4.0, 8.0 mg/L
Details on test conditions:
TEST SYSTEM

Test vessel: 100 mL glass Erlenmeyer flasks
Test volume: 50 mL
Agitation: On a horizontal shaker at 110 rpm
No. of cells per replicate: 5x10^4
No.of vessels per concentration and solvent control (replicates): 3
No.of vessels per dilution water control (replicates): 5
Key result
Duration:
72 h
Dose descriptor:
IC10
Effect conc.:
0.81 mg/L
Nominal / measured:
nominal
Basis for effect:
growth rate
Remarks on result:
other: 95% confidence intervals: 0.09 - 7.49 mg/L
Key result
Duration:
72 h
Dose descriptor:
IC50
Effect conc.:
7.66 mg/L
Nominal / measured:
nominal
Basis for effect:
growth rate
Remarks on result:
other: 95% confidence intervals: 3.51 - 16.7 mg/L
Validity criteria fulfilled:
not specified
Remarks:
The publication did not specify whether the criteria were fulfilled and insufficient data were presented to determine this.
Conclusions:
Based on the nominal concentrations of the test item, the 72h IC50 for Desmodesmus subspicatus was 7.66 mg/L (95% confidence limits 3.51 - 16.7 mg/L). The 72h IC10 was 0.81 mg/L (95% confidence limits 0.09 - 7.49 mg/L).
Executive summary:

In the algal growth inhibition test with Desmodesmus subspicatus, the effects of the test item were determined according to OECD 201 (2006) guideline. The study was conducted under static conditions over a period of 72 hours with 5 concentrations of the test item (0.5, 1.0, 2.0, 4.0, 8.0 mg/L). The test included 5 replicates in the controls and 3 replicates for the solvent control (ethanol) and each test concentration. The concentrations of the test item were not analytically verified. Based on the nominal concentrations of the test item, the 72 hour IC50 for Desmodesmus subspicatus was 7.66 mg/L (95 % confidence limits: 3.51 - 16.7 mg/L). The 72 hour IC10 was 0.81 mg/L (95% confidence limits 0.09 - 7.49 mg/L). The study is considered to be reliable with restriction (Klimisch 2) as it was conducted according to guideline, however no analytical verification of test concentrations was performed and nominal tested concentration were above the water solubility of the test substance (WS = 1.08 mg/L).

Description of key information

Based on the nominal concentrations of the test item, the 72h IC50 for Desmodesmus subspicatus was 7.66 mg/L (95% confidence limits 3.51 - 16.7 mg/L). The 72h IC10 was 0.81 mg/L (95% confidence limits 0.09 - 7.49 mg/L).

Key value for chemical safety assessment

EC50 for freshwater algae:
7.66 mg/L
EC10 or NOEC for freshwater algae:
0.81 mg/L

Additional information

In the algal growth inhibition test with Desmodesmus subspicatus, the effects of the test item were determined according to OECD 201 guideline (2011). The study was conducted under static conditions over a period of 72 hours with 5 concentrations of the test item (0.5, 1.0, 2.0, 4.0, 8.0 mg/L). The test included 5 replicates in the controls and 3 replicates for the solvent control (ethanol) and each test concentration. The concentrations of the test item were not analytically verified. Based on the nominal concentrations of the test item, the 72 hour IC50 for Desmodesmus subspicatus was 7.66 mg/L (95 % confidence limits: 3.51 - 16.7 mg/L). The 72 hour IC10 was 0.81 mg/L (95% confidence limits 0.09 - 7.49 mg/L). The study is considered to be reliable with restriction (Klimisch 2) as it was conducted according to guideline, however no analytical verification of test concentrations was performed.