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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:
1-25 Sep 2008
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
GLP compliance:
yes
Analytical monitoring:
yes
Details on sampling:
During the limit test samples for analysis were taken from both the limit concentration and the control according to the schedule below.
Frequency at t=O h, t=24 h and t=72 h
Volume 2ml
Storage Samples were stored in a freezer until analysis.

At the end of the exposure period, the replicates with algae were pooled at each concentration before sampling.
Vehicle:
yes
Remarks:
M2
Details on test solutions:
The standard test procedures required generation of test solutions, which contained completely
dissolved test substance concentrations or stable and homogeneous mixtures or dispersions.
The testing of concentrations that would disturb the test system was prevented as much as
possible (e.g. film of the test substance on the water surface).
The batch of AHU377 C9 tested was a white powder with a purity of 99.82% and completely
soluble in test medium at the concentrations tested.
Preparation of the test solution started with a loading rate of 100 mg/I applying 25 minutes of
magnetic stirring followed by a 10-minute treatment period with ultrasonic waves to accelerate
the dissolving of the test substance in the test medium. The final test solution was all clear and
colourless.
After preparation, volumes of 50 ml were added to each replicate of the respective test
concentration. Subsequently, 1 ml of an algal suspension was added to each replicate providing
a cell density of 10E4 cells/ml.
Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
Pseudokirchneriella subcapitata, strain: NIVA CHL 1
This system is an unicellular algal species sensitive to
toxic substances in the aquatic ecosystem and has
been selected as an internationally accepted species.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h
Test temperature:
21-24°C
pH:
6.0-9.0
Reference substance (positive control):
no
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
< 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: yield inhibition
Validity criteria fulfilled:
yes
Conclusions:
AHU377 C9 did not reduce growth rate of this fresh water algae species at 100 mgl/l (NOEC). Yield inhibition was statistically inhibited by 17% (NOEC < 100 mg/l). The ECsof or both growth rate reduction (ERC50: 0-72h) and yield inhibition (ERC50:0 -72h) was beyond 100 mgl/l.
Executive summary:

AHU377 C9 did not reduce growth rate of this fresh water algae species at 100 mgl/l (NOEC). Yield inhibition was statistically inhibited by 17% (NOEC < 100 mg/l). The ECsof or both growth rate reduction (ERC50: 0-72h) and yield inhibition (ERC50

0 -72h) was beyond 100 mgl/l.

Description of key information

AHU377 C9 did not reduce growth rate of this fresh water algae species at 100 mgl/l (NOEC). Yield inhibition was statistically inhibited by 17% (NOEC < 100 mg/l). The EC50 for both growth rate reduction (ERC50: 0-72h) and yield inhibition (ERC50

0 -72h) was beyond 100 mgl/l.

Key value for chemical safety assessment

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

Additional information