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:
2018-03-02 to 2018-04-06
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.3 (Algal Inhibition test)
Deviations:
no
Principles of method if other than guideline:
The characterization and stability of the test item have been performed according to cGMP Guidelines.
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
- Physical state: powder
- Appearance: white powder
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Analytical purity: 95.1%
- Source and lot/batch No.of test material: M16HD2757
- Expiration date of the lot/batch: 2018-07-04 (retest date)
- Purity test date: 2016-12-21 (certificate of analysis release date)

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: At room temperature
- Stability under test conditions: not indicated
- Solubility and stability of the test substance in the solvent/vehicle: solubility in water: 62-140 g/L

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Sampling method: Samples were taken before the start of the test and after 24h and 72 hours from each test medium and from the control. Additionally, reserve samples of 4.0 mL were taken for possible analysis. At the end of the exposure period, the replicates with algae were pooled at each concentration before sampling.
- Sample storage conditions before analysis: Stored in a freezer until analysis.

Test solutions

Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Preparation of test solutions started with the highest test concentration of 100 mg/L. No other treatment than vigorous shaking was needed to completely dissolve the test item in test medium. The lower test concentrations were prepared by subsequent dilutions of the highest test concentration in test medium. 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 10^4 cells/mL.
- Controls: yes
- Evidence of undissolved material (e.g. precipitate, surface film, etc): All final test solutions were clear and colourless

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
TEST ORGANISM
- Strain: NIVA CHL 1
- Source (laboratory, culture collection): In-house laboratory culture
- Method of cultivation: Algal stock cultures were started by inoculating growth medium with algal cells from a pure culture on agar. The suspensions were continuously aerated and exposed to light in a climate room at a temperature of 21-24°C. M1 medium was used.

ACCLIMATION
- Pre-culture: 3 days before the start of the test, cells from the algal stock culture were inoculated in M2 medium at a cell density of 1E+04 cells/mL. The pre-culture was maintained under the same conditions as used in the test. Cell density was measured before use.

Study design

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

Test conditions

Hardness:
24 mg CaCO3/L
Test temperature:
24-23 °C
pH:
t=0h: 8.0-8.2
t=72h: 7.9-8.2
Dissolved oxygen:
not applicable
Salinity:
not relevant
Conductivity:
not reported
Nominal and measured concentrations:
Range-finder:
nominal test concentrations: 0.10 and 100 mg/L
measured test concentration t = 0 h: 0.104, 108 mg/L
measured test concentration t = 24 h: 0.102, 109 mg/L
measured test concentration t = 72 h: 0.0877, 103 mg/L

Final test:
nominal test concentrations: 0, 1.0, 3.2, 10, 32 and 100 mg/L
measured test concentration t = 0 h: n.d., 1.27, 4.21, 12.8, 41.4, 127.1 mg/L
corrected * measured test concentration t = 0 h: n.d., 0.998, 3.31, 10.0, 32.5, 100 mg/L
measured test concentration t = 24 h: 0.0000021, 1.23, 4.17, 12.8, 37.7, 124 mg/L
corrected * measured test concentration t = 24 h: 0.00016, 0.967, 3.28, 10.1, 9.98, 29.7, 97.4 mg/L
measured test concentration t = 72 h: 0.0106, 1.09, 3.68, 11.9, 36.6, 116 mg/L
corrected * measured test concentration t = 72 h: 0.0083, 0.858, 2.89, 9.35, 28.8, 91.0 mg/L

* Corrected for the mean recovery of the 100 mg/L samples prepared and analysed on 06 Apr 2018.
n.d. Not detected.
Details on test conditions:
TEST SYSTEM
- Test vessel: 100 mL all-glass flasks
- Type (delete if not applicable): capped vessels
- Material, size, headspace, fill volume: 100 mL all-glass flasks filled with 50 mL test solution
- Initial cells density: 10,000 cells/mL
- Control end cells density: 173 x 10,000 cells/mL (mean)
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: M1; according to the NPR 6505 (“Nederlandse Praktijk Richtlijn no. 6505”) formulated using Milli-RO water (tap-water purified by reverse osmosis
- Detailed composition if non-standard medium was used:
NaNO3 500 mg/L
K2HPO4.3H2O 52 mg/L
MgSO4.7H2O 75 mg/L
Na2CO3.10H2O 54 mg/L
C6H8O7.H2O 6 mg/L
NH4NO3 330 mg/L
CaCl2.2H2O 35 mg/L
C6H5FeO7.xH2O 6 mg/L
H3BO3 2.9 mg/L
MnCl2.4H2O 1.81 mg/L
ZnCl2 0.11 mg/L
CuSO4.5H2O 0.08 mg/L
(NH4)6Mo7O24.4H2O 0.018 mg/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: M2, according to the OECD 201 Guideline, formulated using Milli-RO water.
- Culture medium different from test medium: Yes (M1 versus M2). Three days before the start of the test the algal stock culture (culture in M1) was inoculated in the same culture medium (M2) used in the test. The culture was maintained under the same conditions as used in the test.
- Intervals of measurements: pH was measured at the beginning and at the end of the test. Temperature was continuously measured in a control vessel. At the end of the final test microscopic observations were performed on all test concentrations to observe for any abnormal appearance of the algae.

OTHER TEST CONDITIONS
- Sterile test conditions: no information
- Adjustment of pH: no
- Photoperiod: continuous illumination
- Light intensity and quality: 60 to 120 µE/m2/s when measured in the photosynthetically effective wavelength range of 400 to 700 nm.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable):
- Determination of cell concentrations: [counting chamber; electronic particle counter; fluorimeter; spectrophotometer; colorimeter]: At the beginning, cells were counted using a microscope and a counting chamber. Thereafter, cell densities were determined by spectrophotometric measurement of samples at 720 nm using a spectrophotometer with immersion probe (pathlength = 10mm).
- Effect calculated parameters: specific growth rate and yield

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2
- Range finding study: yes
- Test concentrations: 1.0, 10 and 100% of the SS (setup as combined range finder/limit test)
- Results used to determine the conditions for the definitive study: yes
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.:
17 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 95% C.I. 16-18 mg/L
Key result
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
3.2 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Key result
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
6 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 95% C.I. 5.5-6.6 mg/L
Details on results:
- Exponential growth in the control (for algal test): yes
- Any stimulation of growth found in any treatment: no
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- 72-h EC50 (yield) = 7.4 mg/L (95% C.L. 6.8-7.9 mg/L)
- 72-h NOEC (yield) = 3.2 mg/L
Results with reference substance (positive control):
- Results with reference substance valid? yes
- 72-h EC50 (growth rate) = 1.2 mg/L (95% C.L. 1.1 to 1.2 mg/L)
- 72-h EC50 (yield) = 0.38 mg/L (95% C.L. 0.38 to 0.39 mg/L)

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
A 72-h growth inhibition test with the unicellular green alga Pseudokirchneriella subcapitata was performed with the test substance T003680 according to the OECD guideline 201 (GLP conditions). The analytically confirmed nominal NOEC and EC10 for growth rate inhibition (72h-ErC50) were 3.2 mg/lL and 6.0 mg/L (95% C.I. 5.5-6.6 mg/L), respectively. The analytically confirmed nominal EC50 for growth rate inhibition (72h-ErC50) was 17 mg/L with a 95% confidence interval ranging from 16 to 18 mg/L. The results of the test can be considered reliable without restrictions.