Registration Dossier

Diss Factsheets

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:
Apr 22 - Jul 27, 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: This study was performed according to GLP and the methods applied are fully compliant with OECD TG 201.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2009
Report date:
2009

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Alga, Growth Inhibition Test)
Deviations:
no
GLP compliance:
yes (incl. QA statement)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
Samples of the test item concentrations and the control were taken at the start of the study and after 72 hours.
The quantification of the test material was performed using a Capillary Electrophoresis (CE) method. The samples of the two highest test concentrations (nominal concentrations: 45.45 and 100.00 mg/L) were diluted before analysis. The remaining samples were analyzed directly without any preparation.

Test solutions

Vehicle:
yes
Details on test solutions:
Preparations of 100 ml each were continuously shaken in 300 ml Erlenmeyer flasks by a rotating panel. The flasks were covered with cellulose stoppers.

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Green algae
- Strain: Desmodesmus subspicatus 86.81 SAG
- Source (laboratory, culture collection): sammlung von Algenkulturen, Pfalnzenphysiologisches Institut der Universität Göttingen, 37073 Göttingen
- Age of inoculum (at test initiation): freshly prepared
- Method of cultivation: standard

ACCLIMATION
- Acclimation period: 3 days
- Culturing media and conditions (same as test or not): same
- 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:
-

Test conditions

Hardness:
250 mg/L
Test temperature:
22-23°C
pH:
8
Nominal and measured concentrations:
nominal: 1.0, 1.8, 3.2, 5.6, 10.0 mg/L

The analytically determined concentrations were between 94.4 - 101.8 % at the start and 94.4 - 102.0 % at the end of the experimental part.
Details on test conditions:
TEST SYSTEM
- Test vessel: 3 replicates
- Type (delete if not applicable): open
- Initial cells density: 10000 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes
- Detailed composition if non-standard medium was used:

NH4Cl 15.00000 mg/L
MgCl2 * 6 H2O 12.00000 mg/L
CaCl2 * 2 H2O 18.00000 mg/L
MgSO4 * 7 H2O 15.00000 mg/L
KH2PO4 1.60000 mg/L

FeCl3 * 6 H2O 80 µg/L
Na2EDTA * 2 H2O 100 µg/L

H3BO3 0.18500 mg/L
MnCl2 * 4 H2O 0.41500 mg/L
ZnCl2 0.00300 mg/L
CoCl2 * 6 H2O 0.00150 mg/L
CuCl2 * 2 H2O 0.00001 mg/L
Na2MoO4 * 2 H2O 0.00700 mg/L

NaHCO3 50.00000 mg/L

The pH of the reconstituted water after aeration is approximately 8.
Reference substance (positive control):
yes
Remarks:
potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
1 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
cell number
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
3 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 2.8-3.2
Results with reference substance (positive control):
The sensitivity of the test system has to be demonstrated periodically using potassium dichromate.
Under the given experimental conditions, the test item potassium dichromate showed 72h EC values which are within the recommended range (Yield EC50 0.20 – 0.75 mg/L and Growth rate EC50 of 0.60 –1.03 mg/L).

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The test material, prepared in reconstituted water, was tested in an open static test system. Under the given conditions of this study the 72 h EC50 value for Reduction in Growth Rate was5.3 (4.8- 5.8) mg/L.
Executive summary:

Study Design

The algae were exposed to different concentrations of the test material and the growth was calculated after 24, 48, or 72 hours of exposure in the test media. The study was performed with nominal concentrations of 1.0, 1.8, 3.2, 5.6, and 10.0 mg/L in reconstituted water. The study design included one control and five test material groups with three replicates, each containing 100 mL reconstituted water or test medium and about 10000 cells/mL at the start of the experimental phase. The study was performed in an open static test system. The test material concentrations were analyzed at 0 (start) and 72 hours after start of the experimental part using a capillary electrophoresis method.
This study was performed according to GLP and the methods applied are fully compliant with OECD TG 201.

Results

The limit of detection of the analytical method was 1.6 mg/L. The analytically determined concentrations were between 94.4- 101.8 % at the start and 94.4 - 102.0 % at the end of the experimental part. During the experimental phase of the study, the test material concentrations could be maintained at >=80 % of the initial concentrations. Therefore, the EC50 values were calculated based on the nominal concentrations.

After exposure of Desmodesmus subspicatus for 72 hours the following results were obtained:

 Concentration in mg/L  24h  48h  72h  Inhibition of Growth in %  Reduction in Growth Rate in %
 1  -46.9  -27.9  -19.2  -21.1  -3.8
 1.8  -13.5  5.7  13.8  12.0  3.4
 3.2  12 .6  34.8  64.9  59.5  25.3
 5.6  78.5  85.4  94.7  93.0  65.6
 10.0  81.7  92.5  97.2  96.1  74.0

For the test item, the following EC values for were determined:

NOEC = 1 mg/L

72h EC (Inhibition of Growth) = 3 mg/L (2.8 - 3.2)

72h EC (Reduction in Growth Rate) = 5.3 mg/L (4.8 - 5.8)

Conclusion

The test material, prepared in reconstituted water, was tested in an open static test system. Under the given conditions of this study the 72 h EC50 value for Reduction in Growth Rate was

5.3 (4.8- 5.8) mg/L.