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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:
2020-06 till 2020-11-30
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Details on sampling:
Sampling schedule:

Control : at 72 hours

Test concentration/s : 100 mg/L at 0, 24, 48 and 72 hours
Vehicle:
yes
Details on test solutions:
To bring the test item into solution Acetone was used as solvent carrier. 0.51 mg of the test item was weighed and was dissolved in 5 mL Acetone. The stock solution was prepared to produce the only test item concentration. 0.200 mL of the test item was taken and were filled with dilution water to a volume of 2000 mL This solution was treated for 1 h in an ultrasonic bath and stirred for 24 h on a magnetic stirrer. The pH was measured to be 8.3.
100 mL of the solution were taken and 0.575 mL of the algal inoculum was added to each replicate resulting in a final cell density of 5000 cells/mL
For each test item concentration and the control 6 replicates were prepared. All flasks were sealed with cotton stoppers.
Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Hardness:
Water hardness of the final nutrient medium was 1.3 °dH, corresponding to 22.5 mg/L CaCO3.
Test temperature:
21 - 24 °C
pH:
8.3.
Nominal and measured concentrations:
0.010 mg/L (nominal)
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 0.003 mg/L
Nominal / measured:
meas. (geom. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
Results [mg/L]:

Nominal concentration Analytical values
(geometric mean)
[mg/L] [mg/L]

ErC 50* (0-72 h): > 0.010 > 0.0032

ErC 10* (0-72 h): > 0.010 > 0.0032

NOEC [r]* (tα 0.05): ≥ 0.010 ≥ 0.0032

LOEC [r]* (tα 0.05): > 0.010 > 0.0032
Validity criteria fulfilled:
yes
Conclusions:
No toxic effects against algae were observed at a limit test concentration of nominally
0.010 mg/L at the limit of water solubility under exposure conditions, equalling to an analytical value of 0.0032 mg/L, under exposure conditions.
Executive summary:

No toxic effects against algae were observed at a limit test concentration of nominally
0.010 mg/L at the limit of water solubility under exposure conditions, equalling to an analytical value of 0.0032 mg/L, under exposure conditions.


 

Description of key information

No toxic effects against algae were observed at a limit test concentration of nominally
0.010 mg/L at the limit of water solubility under exposure conditions, equalling to an analytical value of 0.0032 mg/L, under exposure conditions.


 

Key value for chemical safety assessment

EC50 for freshwater algae:
0.003 mg/L
EC10 or NOEC for freshwater algae:
0.003 mg/L

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