9β,11β-epoxy-17,21-dihydroxy-16β-methylpregna-1,4-diene-3,20-dione

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:

08/08/2016-05/09/2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: UNI EN ISO 8692:2012 “Fresh water algal growth inhibition test with unicellular green algae”.

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: OECD Series on Testing and Assessment No 23 - Guidance Document On Aquatic Toxicity Testing Of Difficult Substances And Mixtures ENV/JM/MONO(2000)6.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

9β,11β-epoxy-17,21-dihydroxy-16β-methylpregna-1,4-diene-3,20-dione

EC Number:

213-563-4

EC Name:

9β,11β-epoxy-17,21-dihydroxy-16β-methylpregna-1,4-diene-3,20-dione

Cas Number:

981-34-0

Molecular formula:

C22H28O5

IUPAC Name:

17,21-dihydroxy-16-methyl-9,11-epoxypregna-1,4-diene-3,20-dione

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: supplied by the Sponsor, batch N. 14192-00816
- Expiration date of the lot/batch: January 26, 2018
- Purity test date: 98.6%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: The test item is stored at room temperature at the dark,
following Test Substance Data Sheet (TSDS) supplied by the Sponsor.

Sampling and analysis

Details on sampling:

The test item is stored at room temperature at the dark, following Test Substance Data Sheet (TSDS) supplied by the sponsor.

Test organisms

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Study design

Test type:

not specified

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

the incubation temperature was continuously monitored during the course of the study by a PT100 probe installed in the environmental test chamber. It was in the range 23.9 – 24.0 °C with a mean value of 24.0 °C and a standard deviation of 0.02°C. The temperature range provided by OECD guideline is 24 ± 2 C. The temperature values during the test were within the provided range by guideline.

pH:

Test medium pH was measured with a portable pH meter at the beginning of the test and in each test flask at the end of the test. At the test start, in fresh test media, the pH values were measured sampling an aliquot immediately after test solution preparation, before pouring it in the test flasks. For spent solutions (after 72 hours), pH were measured in each test flask.

Details on test conditions:

The study was performed with the unicellular, fresh water green algae Pseudokirchneriella subcapitata strain, cultured in the laboratories, of the Test Facility and originally purchased from the Institute of Plant Physiology of the university of Goettingen, germany.
The algae were cultured in a climatic chamber at 24°C +/-2°C under continuous uniform illumination in the range 4440-8880 Lux in the spectral range 400-700 nm. The culture medium was the same of the test mediu,: the stock cultures were weekly transferred to fresh medium and maintained in continuous shaking to ensure the necessary amount of CO2 and to keep algae in suspension. Cultures containing deformed or abnormal cells were discarded. Only exponentially growing algal cultures have been used to start the test.

Results and discussion

Effect concentrations

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 1 mg/L

Nominal / measured:

nominal

Basis for effect:

growth rate

Remarks on result:

other: The algae were exposed at only one nominal concentration, 1.0 mg/L, corresponding to the maximum solubility obtainable in test medium and in test conditions.

Details on results:

For the tested concentration, the algal growth rate (r) after 72 hours of exposure was slightly higher than the negative control (mean % inhibition: -0.4%).
At the test end the cell density in the negative control increased on average by a factor of 345. This value complies with the validity criterion of the test, according to the mentioned guidelines, which indicates a minimum increase factor of 16. The negative control also met the other validity criterion, with a coefficient of variation of daily growth rates of 6.5 % (maximum acceptable value 35%) and a coefficient of variation of average growth in negative control replicates during the test period of 5.4 %(maximum acceptable value 7%).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of test item BETA-METHYLEPOXY was tested on Pseudokirchneriella subcapitata.
The percent inhibition of growth rate and yield at 24, 48 and 72 hours of exposition compared to the negative control.