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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:
2019-01-28 - 2019-01-31 (experimental phase)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
under GLP
Cross-reference
Reason / purpose for cross-reference:
reference to other study
Remarks:
OECD 202
Reference
Endpoint:
short-term toxicity to aquatic invertebrates
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2019-01-29 - 2019-01-31 (experimental phase)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
under GLP
Qualifier:
according to guideline
Guideline:
OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)
Version / remarks:
OECD Guideline for Testing of Chemicals No. 202, adopted 13. Apr. 2004: ”Daphnia sp., Acute Immobilisation Test“
Deviations:
no
Qualifier:
according to guideline
Guideline:
EU Method C.2 (Acute Toxicity for Daphnia)
Version / remarks:
Commission Regulation (EC) No. 440/2008, Method C.2. “Daphnia sp. Acute Immo-bilisation Test”, adopted 30. May 2008
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Remarks:
Landesamt für Umwelt, Kaiser-Friedrich-Straße 7, 55116 Mainz, Germany
Specific details on test material used for the study:
The test item was stored in the test facility in a closed vessel at room temperature (20 ± 5°C)
Analytical monitoring:
yes
Details on sampling:
- Concentrations: 0, 100 mg/L
Vehicle:
no
Remarks:
dilution water
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A solution containing 100.5 mg/L in dilution water was prepared.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): none
Test organisms (species):
Daphnia magna
Details on test organisms:
TEST ORGANISM
- Common name: water flea
- Strain/clone: Daphnia magna STRAUS Berlin
- Age at study initiation (mean and range, SD): between 0 and 24 hours
- Method of breeding: Daphnia magna is bred in the laboratory throughout the year. The animals are kept for the use in toxicity tests. They multiply by parthenogenesis, thus being genetically identical. The keeping is performed similar to the method described in the OECD guideline.
Vessels: preserving glasses, nominal volume 2 L
Medium: M4-Medium (recipe of ELENDT)
Food: green algae (Desmodesmus subspicatus)
Medium renewal: twice a week
Photo period: 16/8 hours, using neon tubes
Temperature: 20 ± 2 °C
- Source: Umweltbundesamt Berlin
- Feeding during test
none

METHOD FOR PREPARATION AND COLLECTION OF EARLY INSTARS OR OTHER LIFE STAGES, INCLUDING CULTURING CONDITIONS:
Selection of Daphnia
18 hours and 55 minutes before the start of the test, the adult animals were separated from the young. 40 minutes before test start, the adults were caught with the help of a glass tube, and the newborn daphnia (age < 24h) were sieved from the medium and im-mediately placed into a beaker containing dilution water. After the settling-in period, ani-mals which showed no apparent damage were used for the test.
Switching from M4-medium (husbandry) to Dilution water (test) has been shown not to cause any detrimental effects for test daphnia.
Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
48 h
Post exposure observation period:
none
Hardness:
2.502 mmol/L
250 mg CaCO3/L
Test temperature:
20.4 – 21.3 °C
pH:
7.7 - 7.9
Dissolved oxygen:
8.2 - 8.8 mg/L
Nominal and measured concentrations:
Nominal: 0, 100 mg/L
Measured (t = 0h): 0, 96.2 mg/L
Measured (t = 48h): 0, 103.1 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: beakers
- Type (delete if not applicable): open
- Material, size, headspace, fill volume: glass beakers, nominal volume 50 mL, tall shape, 20 ± 5 mL fill volume
- Volume of solution: 20 ± 5 mL
- Aeration: After preparation, the dilution water was aerated.
- Renewal rate of test solution (frequency/flow rate): none
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): n/a

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: 16/8 hours, using neon tubes

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
Immobility: after 24 and 48 hours
Test item concentration, pH, O2: after 0 and 48 hours

VEHICLE CONTROL PERFORMED: not required
Reference substance (positive control):
yes
Remarks:
Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a current reference study.
Duration:
24 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Key result
Duration:
48 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
NOEC
Effect conc.:
>= 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Duration:
48 h
Dose descriptor:
LOEC
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
mobility
Details on results:
- Behavioural abnormalities: none stated
- Immobilisation of control: none
- Abnormal responses:
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: none
- Effect concentrations exceeding solubility of substance in test medium: none
Results with reference substance (positive control):
- Results with reference substance valid? yes
- Relevant effect levels: 24h EC50
- Limit test: no
- Dose-response test: yes
- ECx: The 24h-EC50 value was determined as 2.05 mg/L. The value was within the requested range for the 24h-EC50 between 0.6 - 2.1 mg/L of potassium dichromate K2Cr2O7 as specified in the OECD guideline.
Reported statistics and error estimates:
As no significant immobilisation occurred, no statistical evaluation was performed.
Validity criteria fulfilled:
yes
Conclusions:
The study was conducted under GLP according to OECD guideline 202 and EU method C.2 on the registered substance itself. The method is to be considered scientifically reasonable with no deficiencies in documentation or deviations from the guidelines, the validity criteria were met. Hence, the results can be considered as reliable to assess the toxicity of the test item resp. the registered substance towards daphnids.
The study was performed as a limit test at 100 mg/L. For the test concentration and the blank control, 20 Daphnia were exposed to the test item for 48 hours in a static test system. After 24 and 48 hours, the immobilised Daphnia were counted.
One of the animals was immobilised in the treatment. None of the animals was immobilised in the blank control. As no significant immobilisation occurs, no statistical evaluation was performed.
Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a current reference study to assure that the test conditions are reliable.
At the start and at the end of the test, the content of the test item in the test solutions was determined using measurement of total organic carbon (TOC). The measured concentration based on TOC measurement was 96 % of the nominal concentration at the beginning of the test and 103 % of the nominal concentration at the end of the test. Therefore, the determination of the results was based on the nominal concentrations.
The 48h EC50 was determined to be >100 mg/L..
Based on the obtained results, the registered substance does not need to be classified as toxic to the environment, neither acutely nor chronic, according to the Regulation (EC) No. 1272/2008.
Executive summary:

The study was conducted under GLP according to OECD guideline 202 and EU method C.2 on the registered substance itself. One valid experiment was performed.

One valid experiment was performed.

The study was performed as a limit test at 100 mg/L. For the test concentration and the blank control, 20 Daphnia were exposed to the test item for 48 hours in a static test system. After 24 and 48 hours, the immobilised Daphnia were counted.

One of the animals was immobilised in the treatment. None of the animals was immobilised in the blank control. As no significant immobilisation occurred, no statistical evaluation was performed.

Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a current reference study to assure that the test conditions are reliable.

At the start and at the end of the test, the content of the test item in the test solutions was determined using measurement of total organic carbon (TOC). The measured concentration based on TOC measurement was 96 % of the nominal concentration at the beginning of the test and 103 % of the nominal concentration at the end of the test. Therefore, the determination of the results was based on the nominal concentrations.

The following results were determined for the test item Yucca schidigera, ext. (species: Daphnia magna).

48h-NOEC ≥ 100 mg/L (nominal)
48h-LOEC > 100 mg/L (nominal)
24h-EC50 > 100 mg/L (nominal)
48h-EC50 > 100 mg/L (nominal)

The test item does not need to be classified as toxic to the environment, neither acutely nor chronic, according to the Regulation (EC) No. 1272/2008.

Data source

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

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)
Version / remarks:
OECD Guideline for the Testing of Chemicals No. 201, adopted 23. Mar. 2006, An-nex 5 corrected: 28 July 2011 “Freshwater Alga and Cyanobacteria, Growth Inhibition Test”
Deviations:
yes
Remarks:
but not affecting the validity / reliability of the study
Qualifier:
according to guideline
Guideline:
EU Method C.3 (Algal Inhibition test)
Version / remarks:
Commission Regulation (EU) No. 2016/266 amending Regulation (EC) No. 440/2008, Annex IV, Method C.3: “FRESHWATER ALGAE AND CYANOBACTERIA, GROWTH INHIBITION TEST,” adopted 07. December 2015
Deviations:
yes
Remarks:
but not affecting the validity / reliability of the study
GLP compliance:
yes (incl. QA statement)
Remarks:
Landesamt für Umwelt, Kaiser-Friedrich-Straße 7, 55116 Mainz, Germany

Test material

Constituent 1
Reference substance name:
Yucca schidigera, ext.
EC Number:
607-033-5
Cas Number:
223749-05-1
IUPAC Name:
Yucca schidigera, ext.
Test material form:
solid: particulate/powder
Remarks:
fine beige
Details on test material:
Storage: Room Temperature (20 ± 5 °C)
Homogeneity: homogeneous
Specific details on test material used for the study:
The test item was stored in the test facility in a closed vessel at 14.0 – 22.7°C.

Sampling and analysis

Analytical monitoring:
yes
Details on sampling:
- Concentrations: 0, 0.32, 1, 3.2, 10, 32, 100 mg/L

Test solutions

Vehicle:
no
Remarks:
algal medium
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: A stock solution containing 100.0 mg/L in algal medium (demineralised water enriched with minerals but without algae) was prepared. The lower treatments were prepared by dilution of this stock solution with algal medium.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): none

Test organisms

Test organisms (species):
Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)
Details on test organisms:
TEST ORGANISM
- Common name: Unicellular freshwater green alga
- Strain: Desmodesmus subspicatus, SAG Strain Number 86.81
- Source (laboratory, culture collection): The culture of Desmodesmus subspicatus was obtained in January 2016 by MBM Sci-encebridge GmbH (Institut für Pflanzenphysiologie of Universität Göttingen).
- Method of cultivation: The algae are kept as stock culture on solid agar at 2 - 8 °C. From the stock culture, a permanent culture was prepared. From an aliquot of the permanent culture, the pre-culture was prepared.

Study design

Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
72 h
Post exposure observation period:
none

Test conditions

Test temperature:
22.4 – 24.0 °C
pH:
7.8 - 10.1
Nominal and measured concentrations:
Nominal: 0 / 0.32 / 1 / 3.2 / 10 / 32 / 100 mg/L
Measured (TOC, t = 0h): 0 / 0 / 0 / 1.0 / 6.3 / 25.9 / 96.2 mg/L
Measured (TOC, t = 72h): 0 / -0.4 / 0.4 / 0.6 / 1.8 / 9.2 / 27.9 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: flasks
- Type (delete if not applicable): open (covered with perforated plastic foil acting as a stopper)
- Material, size, headspace, fill volume: glass flasks total volume 65 mL, fill volume: 45 ± 1 mL
- Renewal rate of test solution (frequency/flow rate): none
- Initial cells density: 2.6 *10E3 cells/mL
- Control end cells density: 491910 cells/mL
- No. of vessels per concentration (replicates): 3 replicates for each treatment
- No. of vessels per control (replicates): 6 replicates for the blank control
- No. of vessels per vehicle control (replicates): not required

GROWTH MEDIUM
- Standard medium used: yes

OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: 5000 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter
- Other: appearance of the algae / abnormalities

TEST CONCENTRATIONS
- Spacing factor for test concentrations: as indicated in the guideline
Reference substance (positive control):
yes
Remarks:
Potassium dichromate K2Cr2O7 (CAS No. 7778-50-9) was used as positive control in a separate reference test.

Results and discussion

Effect concentrationsopen allclose all
Key result
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
> 100 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
not determinable
Remarks:
Due to the low inhibition of the growth rate no 72h-ErC50 can be determined.
Duration:
72 h
Dose descriptor:
EC50
Effect conc.:
23.48 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks:
yield
Remarks on result:
other: 95% CI: 19.04 – 28.95 mg/L
Remarks on result:
other: Significant inhibition of algal growth was observed at the following concentrations: 10 – 100 mg/L (nominal)
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
1 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
1 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks:
yield
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
6.3 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
6.3 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks:
yield
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
10.62 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
other: 95% CI: 6.76 – 14.81 mg/L
Duration:
72 h
Dose descriptor:
EC10
Effect conc.:
0.41 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
test mat.
Basis for effect:
biomass
Remarks:
yield
Remarks on result:
other: 95% CI: 0.24 – 0.72 mg/L
Details on results:
- Exponential growth in the control (for algal test): yes
- Observation of abnormalities (for algal test): none
- Any stimulation of growth found in any treatment: yes
- Any observations (e.g. precipitation) that might cause a difference between measured and nominal values: no
- Effect concentrations exceeding solubility of substance in test medium: none
Results with reference substance (positive control):
- Results with reference substance valid? yes
Parameter Value 95% confidence interval
72h ErC50 0.65 mg/L 0.60 mg/L – 0.71 mg/L
72h EyC50 0.28 mg/L 0.21 mg/L – 0.38 mg/L
Reported statistics and error estimates:
Calculation of results was performed with the help of validated software (Microsoft Excel ®). The estimation of the biological data was accomplished using the software ToxRat® Professional, version 3.2.1.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The study was conducted under GLP according to OECD guideline 201 and EU method C.3 on the registered substance itself. The method is to be considered scientifically reasonable with no deficiencies in documentation or deviations from the guidelines, the validity criteria were met. Hence, the results can be considered as reliable to assess the toxicity of Yucca schidigera, ext. towards algae.
Significant inhibition of algal growth was observed at the following concentrations: 10 – 100 mg/L
At the start and at the end of the test, the content of the test item in the test solutions was estimated by determination of the total organic carbon (TOC) content in the test solutions using a carbon analyser. In the two lowest treatments (0.32 and 1 mg/L nominal) no test item could be detected.
At the end of the test, much less test item was measured than at the beginning. That means at the end of the test, the measurable test item concentration was biased by the presence of the test organism (adsorption or ingestion onto the algae cells). Test item was present but partly not measurable in the test solutions. The parallel Daphnia study showed that the test item is stable. For this reason, the measured initial values are used for statistical evaluation (cf. OECD Guideline No. 201, §40).
No inhibition has occurred in the two lowest treatments and no test item could be detected (< limit of quantification). Therefore, these two concentrations were not used for statistical evaluation, because they are not required.
Due to the low inhibition of the growth rate no 72h-ErC50 can be determined.
Hence, it does not need to be classified as hazardous to the environment, neither acute nor chronic, according to Regulation 1272/2008 and amendments.
Executive summary:

The study was conducted under GLP according to OECD guideline 201 and EU method C.3 on the registered substance itself.

One valid experiment was performed.

The study was performed using 6 concentrations ranging from 0.32 to 100 mg/L (nominal concentration). Incubation time (test system Desmodesmus subspicatus) was 72 hours. The cell concentration of each replicate was determined by measuring the cell numbers every 24 hours with an electronic particle counter. Growth rate µ and the yieldwere determined from the cell number at the respective observation times.

Significant inhibition of algal growth was observed at the following concentrations: 10 – 100 mg/L (nominal)

 

At the start and at the end of the test, the content of the test item in the test solutions was estimated by determination of the total organic carbon (TOC) content in the test solutions using a carbon analyser. In the two lowest treatments (0.32 and 1 mg/L nominal) no test item could be detected.

At the end of the test, much less test item was measured than at the beginning. That means at the end of the test, the measurable test item concentration was biased by the presence of the test organism (adsorption or ingestion onto the algae cells). Test item was present but partly not measurable in the test solutions. The parallel Daphnia study showed that the test item is stable. For this reason, the measured initial values are used for statistical evaluation (cf. OECD Guideline No. 201, §40).

No inhibition has occurred in the two lowest treatments and no test item could be detected (< limit of quantification). Therefore, these two concentrations were not used for statistical evaluation, because they are not required.

Due to the low inhibition of the growth rate no 72h-ErC50 can be determined.

 

The 72h-EC50 values of potassium dichromate (K2Cr2O7, CAS No. 7778-50-9) were determined in a separate reference test. The values lay within the range of the laboratory (growth rate 0.65 - 1.10 mg/L, yield 0.21 – 0.66 mg/L).

 

The following results for the test item Yucca schidigera, ext. were determined:

 

Table Results of the test item

Endpoint

NOEC

LOEC

EC10

EC50

Growth Rate

1.00 mg/L

6.30 mg/L

10.62 mg/L

n.d.

Yield

1.00 mg/L

6.30 mg/L

0.41 mg/L

23.48 mg/L

Note: According to the guideline, NOEC is determined by comparing of the respective treatment with the blank control. Statistically insignificant variation is considered as “no observed effect”, although the EC10 which is read from the graph toxicity vs. concentration may lie lower.

 

The test item does not need to be classified as hazardous to the environment, neither acute nor chronic, according to Regulation 1272/2008 and amendments.