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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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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:
2018
Report Date:
2018

Materials and methods

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

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: crystalline

Sampling and analysis

Analytical monitoring:
yes

Test solutions

Vehicle:
yes
Details on test solutions:
Preparation of stock solution:
The preparation of stock and test solutions was based on the preliminary non GLP range finding test [9]. As the Range Finding Test was not performed in compliance with the GLP-Regulations it is excluded from the Statement of Compliance in the final report, but the raw data of this test are archived under the study code of present study. The stock solution was prepared by measuring 300.12 mg of test item into 3 000 ml OECD growth medium. The suspension was stirred for 24 hours. After stirring the suspension was filtered through a 0.2 μm WhatmanTM ME24 (Mixed cellulose ester) filter. The first 100 ml filtrate was disposed. The concentration of the test item in the filtrate (stock solution) was determined by UHPLC. The measured value was 0.17 mg/L.
Preparation of test solutions:
Five test solutions of different concentration were prepared by mixing appropriate volume of OECD medium and stock solution of the test item. The maximum separation factor between of test vessels was 1.2. Two additional replicates were prepared for controlling the abiotic degradation of the test substance. These test vessels were not inoculated with alga inoculum culture. The following table shows the preparation of test solutions. The volume of the prepared dilution levels was 300 ml except the control solution which was 600 ml.

Test organisms

Test organisms (species):
Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)
Details on test organisms:
Test species: Pseudokirchneriella subcapitata (Korshikov) F.Hindák (formerly known as Selenastrum capricornutum and Raphidocelis subcapitata)
Source: Culture Collection of Algae and Protozoa, Scottish Marine Institute (www.ccap.ac.uk)

Study design

Test type:
static
Water media type:
freshwater
Limit test:
yes
Total exposure duration:
72 h

Test conditions

Test temperature:
The temperature inside the incubator at the test vessels was measured and registered continuously by Extech SD200 thermometer and datalogger. Throughout the test the temperature was nearly constant.
pH:
At the beginning of the test the pH values were measured in the remaining test solution of the concurrent test vessels at each dilution level. At the end of the test the pH values were measured in each test vessel. The pH of test solutions was not adjusted at the beginning of the test.
Nominal and measured concentrations:
In the test the following nominal concentrations were applied: 0.17; 0.16; 0.15; 0.14 and 0.11 mg/L. At the end of the test the measured concentrations of Estradiol-17ß-acetate in the test samples were out of the validated concentration range. Their concentrations were below the analytical detection limit (DL: 0.01 mg/L). According to GHS, Annex 9 the concentrations which were below the analytical detection limit were considered to be half of detection limit (0.005 mg/L).
Details on test conditions:
The test organism was grown and hold in OECD medium which was used also for preparing test item solutions. The stock solution was prepared by measuring 300.12 mg of test item into 3 000 ml OECD growth medium. The suspension was stirred for 24 hours. After stirring the suspension was filtered through a 0.2 μm WhatmanTM ME24 (Mixed cellulose ester) filter. The first 100 ml filtrate was disposed. The concentration of the test item in the filtrate (stock solution) was determined by UHPLC. The measured value was 0.17 mg/L. The toxic property of test item was investigated at five concentrations which were prepared by different dilutions of stock solution of test item.

Results and discussion

Effect concentrationsopen allclose all
Duration:
72 h
Dose descriptor:
EC10
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
not determinable
Duration:
72 h
Dose descriptor:
EC20
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
not determinable
Key result
Duration:
72 h
Dose descriptor:
EC50
Conc. based on:
test mat.
Basis for effect:
growth rate
Remarks on result:
not determinable
Duration:
72 h
Dose descriptor:
LOEC
Effect conc.:
0.026 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Duration:
72 h
Dose descriptor:
NOEC
Effect conc.:
0.024 mg/L
Conc. based on:
test mat.
Basis for effect:
growth rate
Details on results:
As the test item had only slight toxic effect up to its solubility concentration the value of EC50 at 72 h could not be determined. The No Observed Effect Concentration and Lowest Observed Effect Concentration for the test item were calculated by ToxRat® software with Fisher’s exact binominal test with Bonferroni correction for specific growth rate and yield.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Acute toxic effect of Estradiol-17ß-acetate was investigated in Freshwater Alga and Cyanobacteria, Growth Inhibition Test (according to OECD 201 guideline). In the test the test item had only slight toxic effect even in the highest concentration (0.027 mg/L) at 72 h. According to the Council Regulation (EC) 440/2008 Estradiol-17ß-acetate is not hazardous to the aquatic environment. The 72 h EC50 higher than the water solubility of test item.
As the analytical method used to determine the concentration of Estradiol-17ßacetate in test samples was not validated in compliance with GLP principles and parts of the reported results are based on calculations the toxicity results must be interpreted by precaution!