(15α)-3-Methoxy-17-oxoandrosta-3,5-dien-15-yl acetate

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:

72 h

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

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

1

Reference substance name:

(15α)-3-Methoxy-17-oxoandrosta-3,5-dien-15-yl acetate

EC Number:

604-156-6

Cas Number:

139667-09-7

Molecular formula:

C22H30O4

IUPAC Name:

(15α)-3-Methoxy-17-oxoandrosta-3,5-dien-15-yl acetate

Test material form:

solid: particulate/powder

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Details on test solutions:

The Acetoxy-AD-enolether has a very low solubility in aquatic solutions so its concentration cannot be determined by UHPLC from aquatic solutions directly.
The concentration of Acetoxy-AD-enolether was determined only in the saturated stock solution by a non-validated HPLC method using a previous liquid/liquid extraction. The other test concentrations of the test item was calculated from the measured stock solution concentration. At the end of the study the concentrations of the test item in test vessels were not measured. The stock solution was prepared by measuring 200.43 mg of test item into 2 000 ml OECD growth medium. After one hour stirring and ultrasonication the suspension was filtered through 0.2 μm WhatmannTM ME24 filter. The concentration of the filtrate (stock solution) was 0.074 mg/L.

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)
Batch: CCAP 278/4
Date of arriving: 27 October 2017

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:

The concentration of Acetoxy-AD-enolether was determined only in the saturated stock solution by a non-validated HPLC method using a previous liquid/liquid extraction. The other test concentrations of the test item was calculated from the measured stock solution concentration. At the end of the study the concentrations of the test item in test vessels were not measured. The stock solution was prepared by measuring 200.43 mg of test item into 2 000 ml OECD growth medium. After one hour stirring and ultrasonication the suspension was filtered through 0.2 μm WhatmannTM ME24 filter. The concentration of the filtrate (stock solution) was 0.074 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. OECD medium was used for dilution of stock solution. In the test the following measured and calculated concentrations were applied: 0.074; 0.050; 0.037; 0.025 and 0.019 mg/L.

Details on test conditions:

Preparation and breeding of inoculum culture: The inoculum culture was prepared four days before starting the test and it was bred in incubator at 21 ± 2 °C. At the end of incubation the cell density of the inoculum culture was determined with a Bürker chamber. The cell concentration was 2 291 667 cell/ml
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 200.43 mg of test item into 2 000 ml OECD growth medium. After one hour stirring and ultrasonication the suspension was filtered through 0.2 μm WhatmannTM ME24 filter. The concentration of the filtrate (stock
solution) was 0.074 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 1.5. 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. The presented nominal concentrations were calculated from the measured stock solution concentration. The alga inoculum culture was diluted 461.54 times so the initial alga cell concentration in every dilution and the control levels were 4 965 cells/ml.
Preparation of test vessels: Three replicates were prepared at every test and six at the control level. The vessels contained 75 ml test media.
Test procedure: The test vessels were closed with silicone stopper and kept in the Binder KBW 400 incubator. For the proper mass transfer of carbon dioxide glass tubes with filter were placed through silicone stoppers. The test was maintained under static conditions for a period of 72 hours. The temperature during the test remained in the 21 ± 2 °C range. The temperature data were harvested by Extech SD200 datalogger. The vessels were shaken and illuminated continuously in the incubator. The vessels were placed randomly into the incubator and were repositioned daily after sampling.

Results and discussion

Effect concentrations

Duration:

72 h

Dose descriptor:

EC50

Remarks on result:

not determinable

Details on results:

According to the test results Acetoxy-AD-enolether has no toxic effect on alga growth rate even at its saturated concentration (0.074 mg/L).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Acute toxic effect of Acetoxy-AD-enolether was investigated in Freshwater Alga and Cyanobacteria, Growth Inhibition Test (according to OECD 201 guideline). According to the test results Acetoxy-AD-enolether has no toxic effect on alga growth rate even at its saturated concentration (0.074 mg/L).
According to the Council Regulation (EC) 440/2008 Acetoxy-AD-enolether is not hazardous to the aquatic environment [72 h EC50 (for algae or other aquatic plants) > saturated concentration of Acetoxy-AD-enolether (0.074 mg/L)]. As the reported results are based on calculated concentration data which are gained out of a non-validated HPLC method, the toxicity results must be interpreted by precaution!