13-ethyl-3-methoxygona-2,5(10)-dien-17β-ol

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

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

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

13-ethyl-3-methoxygona-2,5(10)-dien-17β-ol

EC Number:

238-513-9

EC Name:

13-ethyl-3-methoxygona-2,5(10)-dien-17β-ol

Cas Number:

14507-49-4

Molecular formula:

C20H30O2

IUPAC Name:

(1S,3aS,3bR,9bS,11aS)-11a-ethyl-7-methoxy-1H,2H,3H,3aH,3bH,4H,5H,6H,9H,9bH,10H,11H,11aH-cyclopenta[a]phenanthren-1-ol

Test material form:

solid: crystalline

Details on test material:

Test Item: Gonol
CAS No.: 14507-49-4
Batch No.: 242012N
Physical state: solid, crystalline substance
Colour: white
Storage: at a temperature of 15 to 30 °C

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. 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 150.40 mg of test item into 1 500 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 80 ml filtrate was disposed. The concentration of the test item in the filtrate (stock solution) was determined by UHPLC. The measured value was 0.178 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 1.33. 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):

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

Details on test organisms:

Test species: Pseudokirchneriella subcapitata (Korshikov) F.Hindák (formerly known as Selenastrum capricornutum)
Source: UTEX The Culture Collection of Algae (USA)
Batch: UTEX ID. number: 1648
Date of arriving: 28 November 2014

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: 0.178; 0.148; 0.119; 0.095 and 0.071 mg/L. The following concentrations were calculated from the initial and ending values and were applied for the statistical evaluation in the test: 0.046; 0.039; 0.022; 0.020 and 0.016 mg test item/L. The test item concentrations of the abiotic controls were 0.143 (in light) and 0.143 (in darkness) 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 150.40 mg of test item into 1 500 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 80 ml filtrate was disposed. The concentration of the test item in the filtrate (stock solution) was determined by UHPLC. The measured value was 0.178 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 concentrations

Remarks on result:

not determinable because of methodological limitations

Details on results:

As the test item had got only slight toxic effect up to its solubility concentration the values of EC10; EC20 and 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:

not applicable

Remarks:

As parts of the reported results are based on calculation or on analytically measured concentration data which are out of validation range or below the detection limit, the toxicity results must be interpreted by precaution!

Conclusions:

Acute toxic effect of Gonol was investigated in Freshwater Alga and Cyanobacteria, Growth Inhibition Test (according to OECD 201 guideline). In the test the test item had no toxic effect even in the highest concentration (0.046 mg/L) at 72 h.