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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019
Report Date:
2019

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
Version / remarks:
2011
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 73465
- Expiration date of the lot/batch: 2019-03-22

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
At the start and at the end, samples were taken from one additional
replicate of the test item concentration and the control. Each sample
was given in a 20 mL headspace vial, covered with aluminium tops
with PTFE seals. Approximately 15 mL sample was transferred from
the replicate directly into the headspace vial.

Test solutions

Vehicle:
no
Details on test solutions:
Five test item concentrations were prepared with dilution water
separately in a geometric series with a separation factor of 2 and
were tested as follows: 10.0 - 20.0 - 40.0 - 80.0 - 160 mg/L.
The dilution levels were based on the results of a preliminary range
finding test (non-GLP).

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Common name: green algae
- Strain: CCAP 278/4
- Source (laboratory, culture collection): Culture Collection of Algae and Protozoa (CCAP), SAMS Research Services Ltd, Dunstaffnage Marine Laboratory, Dunbeg, OBAN; Argyll PA37 1QA, Scotland, UK
- Method of cultivation: Fresh stocks are prepared every month on Z-Agar. Light intensity amounts to 2590 - 5180 lux corresponding to 35 - 70 µE m-2 s-1 for 24 hours per day.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h

Test conditions

Hardness:
33 mg/L as CaCO3
Test temperature:
23-24 °C
pH:
7.89 - 8.20 (test start)
6.81 - 8.89 (test end)
Conductivity:
137 µS/cm
Nominal and measured concentrations:
Nominal: 10, 20, 40, 80 and 160 mg/L
Measured (0h): 10.8, 21.6, 41.0, 81.5 and 191 mg/L
Measured (72h): 10.6, 20.4, 38.0, 81.5 and164 mg/L
measured > 80% nominal
Details on test conditions:
TEST SYSTEM
- Test vessel: sterile Erlenmeyer flasks, volume: 250 mL, sealed with cotton wool plugs
- Initial cells density: 6442 cells/mL
- Control end cells density: 1540086 cells/mL
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: according to guidelines
- Total organic carbon: < LOQ
- Alkalinity: 1 mmol/L
- Conductivity: 141 µS/cm
- Culture medium different from test medium: no
- Intervals of water quality measurement: The pH-value at the start of the exposure was measured out of one additional replicate of the test item concentrations and the control. At the end of the exposure it was measured from pooled replicates of the test item concentrations and control, respectively. The room temperature was measured continuously. Light intensity was measured prior to the start of the exposure.

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: 24h light
- Light intensity and quality: 5281 - 6999 lx

EFFECT PARAMETERS MEASURED: Cell density was measured daily via Chlorophyll a-fluorescence, excitation at 436 nm, emission at 685 nm. Dilution water was used as a background signal. Self-fluorescence was observed in the preliminary range finding test at the concentration of 120 mg/L. A separate replicate of each test item concentration was prepared without algae and treated like the other test replicates. The self-fluorescence of the measuring points between 24 and 72 hours was taken into account in the evaluation. Microscopic evaluation of the cells at the start and end of the exposure was carried out. The cells were checked for unusual cell shapes, colour differences, differences in chloroplast morphology, flocculation, adherence of algae to test containers and aggregation of algae cells.
Reference substance (positive control):
yes
Remarks:
Potassium dichromate

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
107 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: analytically verified
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
55 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: analytically verified
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): none
- Unusual cell shape: no
- Colour differences: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
Results with reference substance (positive control):
- Results with reference substance valid? yes
- EC50: 0.799 mg/L
- validity range: 0.753 ± 0.544

Applicant's summary and conclusion

Validity criteria fulfilled:
yes