Registration Dossier

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:
Jan 11 - 14, 2013
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:
2013
Report Date:
2013

Materials and methods

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

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid: viscous

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 samples obtained were mixed with Acetonitrile proportionally 1:1 and immediately deep frozen (approximately at -20°C). The analysis was performed under GLP conditions using a LC-MS/MS-Analysis method.

Test solutions

Vehicle:
yes
Details on test solutions:
The test medium (reconstituted water and test item) was prepared freshly. Therefore, the calibrated flask with test medium was treated in an ultrasonic device for 1 hour. Subsequently, the preparation was stirred with a magnetic stirrer for further 23 hours. Afterwards, the formulation was passed through a nutsch filter with a pore size of 10-16 µm. The filtrate was used for the study.

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:
yes
Total exposure duration:
72 h
Post exposure observation period:
-

Test conditions

Hardness:
250 mg/L
Test temperature:
22.4-23.6°C
pH:
7.8 - 9
Nominal and measured concentrations:
nominal: 0, 100.0 mg/L
measured initial: measured (72 h): < LOQ, 11.8 mg/L

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

FeCl3 * 6 H2O 0.06400
Na2EDTA * 2 H2O 0.10000

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

NaHCO3 50.00000

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:
EC10
Effect conc.:
> 26.2 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 26.2 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
> 26.2 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 26.2 mg/L
Nominal / measured:
meas. (arithm. mean)
Conc. based on:
test mat.
Basis for effect:
biomass
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:
Under the conditions of the present study, the 72h EC50 values are >26.2 mg/L (nominal >100 mg/L) for the growth rate and for yield.
Executive summary:

Study Design

The objective of this study was to determine the influence of the test item on the growth and growth rate of the unicellular green algal species Desmodesmus subspicatus. The study design included one control group with six replicates and one test item groups with six replicates, each containing 100 mL reconstituted water or test medium and about 10000 cells/mL at the start of the experimental phase. Stability testing of the chemically similar test item Art. 472264 at a nominal concentration of 100 mg/L  in open vessels revealed a recovery rate of 83.2% after 72 hours. Therefore, the study was performed in open vessels. The study was performed as a limit test with a filtrate with nominal 100 mg/L in reconstituted water. The growth of the algae was calculated after 24, 48, and 72 hours exposure in the test item and control group. Analytical controls of the test item preparation were performed at the start of the study and after 72 hours.
This study was performed according to GLP and the methods applied are fully compliant with OECD TG 201.

Results

The analytically determined test item concentration immediately after preparation of the medium was 41 % and 72 hours thereafter 12 % of the nominal concentration, respectively.

During the experimental phase of the study, the test item concentration could not be maintained within ± 20% of the initial analytical concentration. Therefore, the EC values were calculated with the mean analytical concentration.

EC values:

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

Growth rate Yield

EC 10 (mg/L) > 26.2 > 26.2

EC 50 (mg/L) > 26.2 > 26.2

Conclusion

The test material, solved in reconstituted water, was tested in an open static test system. Under the conditions of the present study, the 72h EC50 values are >26.2 mg/L (nominal >100 mg/L) for the growth rate and for yield.