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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:
toxicity to aquatic algae and cyanobacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From September, 25th to 28th, 2001
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study performed according to GLP methods and OECD 201/EEC C.3 guideline compliant.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2001
Report Date:
2001

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): MAJANTOL®
- Substance type: Pure active product
- Physical state: Liquid, highly viscous, colourless
- Storage condition of test material: Room temperature, protected from light and moisture.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations:
Nominal = 6.25 - 12.5 - 25 - 50 - 100 mg/L
Measured = 7.2 - 15 - 31 - 64 - 131 mg/L
- Sampling method: Separate replicates for test item analysis were prepared and incubated under test conditions.
Test item and control were sampled at begining (0h) and end (72h) of test.
Sample at 0h was provided without algae;
Sample at 72h was provided with the same density af alga as the test replicates.
- Sample storage conditions before analysis:

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)

Dilutions of test item into test medium was ensure by a 30 minute ultrasound treatment at room temperature.

At the test start fluorescence was measured before application of the test item. Application was carried out by adding appropriate volumes of stock solution to the test replicates.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Scenedesmus subspicatus
- Strain: CHODAT SAG 86.81
- Source (laboratory, culture collection):
Sammlung von Algenkulturen (SAG),
Pflanzenphysiologisches Institut der Universität Göttingen,
Nikolausberger Weg 18, D-37073 Gottingen
- Age of inoculum (at test initiation): 4d
- Method of cultivation: Fresh stocks were prepared every month on Z-Agar. Light intensity amounted 35-70 µE/m2 .s for 24 h per day.

ACCLIMATION
- Acclimation period: 4 days
- Culturing media and conditions (same as test or not): same as test
- Any deformed or abnormal cells observed: None

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
4 days after end of exposure.

Test conditions

Hardness:
no details reported
Test temperature:
mean value: 22.0°C
min: 21.6°C
max: 22.4°C
pH:
Between 7.88 and 8.73 taking into consideration all cultures (with or without test item).
Dissolved oxygen:
no details reported
Salinity:
no details reported
Nominal and measured concentrations:
nominal concentrations : 6.25 - 12.5 - 25 - 50 - 100 mg/L
corresponding to
overall mean measured concentrations: 7.2 - 15 - 31 - 64 - 131 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: Plastic cuvettes (Ø 50 mm), transparent, with top, volume: 20mL
- Initial cells density: 8825 cells/mL
- Control end cells density: 594880 cells/mL
- No. of organisms per vessel: 10x10^4 cells per vessel
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): none

GROWTH MEDIUM
- Standard medium used: yes, according to guideline.

OTHER TEST CONDITIONS
- Photoperiod: 24 h/d light
- Light intensity and quality: Nominally 60-120 µE/m².s (according to EEC Guideline)

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Chlorophyll-impulsfluorometer
- Chlorophyll measurement: Chlorophyll-impulsfluorometer

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study: yes (details in test report)

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
7.2 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks:
& biomass growth
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
19 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks on result:
other: 17-21 mg/L (95% Confidence interval)
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
27 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks:
(Rate -related inhibition)
Remarks on result:
other: 25-30 mg/L (95% Confidence interval)
Details on results:
No remarks
Results with reference substance (positive control):
No details provided in test report concerning the results of the positive control.
Reported statistics and error estimates:
NOEC:
One way analysis of variance (ANOVA) and DUNNETT’s test of biomass integrals and growth rate, respectively were carried out for the determination of statistically significant differences compared to control replicates. When running a one w ay analysis of variance a normality test was done and an equal variance test first. P-values for both normality and equal variance test were 0.05. The α-value for ANOVA and DUNNETT’s test (acceptable probability of incorrectly concluding that there is a diffence) was α=0.05.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
In this study MAJANTOL® was found to inhibit the growth ofthe freshwater green alga Scenedesmus subspicatus at concentrations more than 7.2 mg/L (biomass growth an growth rate). The NOEC was 7.2 mg/L (inhibition of biomass growth and inhibition of growth rate). The EC50-values for inhibition of biomass growth (EbC50) and specific growth rate (ErC50) after 72h were 19 (17 - 21) and 27 (25 - 30) mg/L, respectively. Inhibition effects were found to be reversible (all effect levels given as mean measured test concentrations).
Executive summary:

The acute toxicity of MAJANTOL® (batch number 50695699) to the unicellular freshwater green alga Scenedesmus subspicatus was determined according to the principles of OECD-Guideline 201 and EEC Directive 92/69/EEC Method C.3, at Dr U. Noack-Laboratorium für Angewandte Biologie in 31157 Sarstedt, Germany from September 25 to 28, 2001.


The study was conducted under static conditions over a duration of 72 hours with an initial cell density of nominally 10^4 c
ells/mL. 5 concentration levels were tested in a geometrical series with a dilution factor of 2:
nominal: 6.25 -
12.5 - 25 - 50 - 100 mg/L
corresponding to
overall mean measured concentrations: 7.2 -
15 - 31 - 64 - 131 mg/L


3 replicates were tested for each concentration level and 6 replicates for control.

The test item was clearly dissolved throughout the test.

Microscopic evaluation of the cells at the start and end of the incubation period revealed no morphological abnormalities.


Water quality parameters of pH-value, measured at 0 and 72 h, and room temperature, measured continuously, were determined to be within the acceptable limits.


The concentrations of the test item MAJANTOL® were determined from all freshly prepared media after 0h and from old media after 72h via GC/MS. All effect levels are given based on the mean measured concentrations of MAJANTOL®. Details of the analytical results are given in part 10 of test report.

The effects of MAJANTOL®, based on mean measured concentrations are :

- EC50-values for inhibition of biomass growth (EbC50) and specific growth rate (ErC50) after 72h were 19 (17 - 21) and 27 (25 - 30) mg/L, respectively. Inhibition effects were found to be reversible (all effect levels given as mean measured test concentrations).