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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:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Principles of method if other than guideline:
This method succeeded the previous OECD Guideline No. 201 'Alga, Growth Inhibition Test' (1984) and EU Method C.3 'Algal inhibition test' (1992).
GLP compliance:
yes (incl. QA statement)
Analytical monitoring:
yes
Vehicle:
no
Details on test solutions:
PRETREATMENT OF TEST ITEM:
- 125 mg of the test substance was added to 1 litre of dilution water
- treated for 60 s at 8000 rpm with an ultra-turrax
- stirred for 24 h on a magnetic stirrer
- undissolved particles of the test item were removed by filtration using an aseptic filter (Serum Acrodisc® 37 mm Syringe Filter with GF/02 μm Supor® Membrane PN 4525 )
- pH was measured to be pH 6.2
Test organisms (species):
other: Scenedesmus subspicatus CHODAT (New scientific name: Desmodesmus subspicatus)
Details on test organisms:
- stock culture: non-axenic strain obtained from the Institute of Plant Physiology at the University of Göttingen (Germany);  exponentially-growing stock cultures maintained under constant  temperature conditions (23 +/- 2 °C), light intensity (60 - 120 µE. x  mE-2 x sE-1), cell density measured using a microcell counter
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Hardness:
No data
Test temperature:
21 - 25 +/- 2 °C
pH:
8.0 at 0 hours, 8.8 after 72 hours
Dissolved oxygen:
No data
Salinity:
No data
Details on test conditions:
TEST SYSTEM:
- test vessels: 300 ml Erlenmeyer flasks with cotton stoppers
- culturing apparatus: light chamber, temperature 21 to 25 °C, continuous uniform illumination (spectral range 400 to 700 nm) 
- light intensity: 60 - 120 µE x mE-2 x sE-1 (4000 - 8000 lx)
- test cultures: final cell density 5000 cells/ml
- method of administration: direct weighing
- test concentration: 1 (100 mg/l) plus 1 control
- replicate: 3 (per concentration), 6 (per control)
- test parameter: growth and growth rate
Reference substance (positive control):
no
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: Results relating to yield (EyCx, NOEC [y])
Details on results:
The results are expressed in terms of nominal concentrations. Recovery rates correspond to 101.3 % of nominal values at 0 hours, and to 90.1 % of nominal values at 72 hours, respectively.
Validity criteria fulfilled:
yes
Conclusions:
In 72 h the concentration of the test item which reduces the growth rate of Scenedesmus subspicatus CHODAT by 50 % is > 100 mg/l.
Executive summary:

In 72 h the concentration of the test item which reduces the growth rate of Scenedesmus subspicatus CHODAT by 50 % is > 100 mg/l. The result relates to nominal concentration as analytical monitoring shows stability of the test substance during the experiment (Currenta, 2009).

Description of key information

In 72 h the concentration of the test substance which reduces the growth rate of Scenedesmus subspicatus CHODAT by 50 % is > 100 mg/l. The result relates to nominal concentration as analytical monitoring shows stability of the test substance during the experiment (Currenta, 2009).

Key value for chemical safety assessment

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

Additional information

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