2-methylcyclopentane-1,3-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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

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:

2-Methylcyclopentane-1,3-dione

Cas Number:

765-69-5

Molecular formula:

C6H8O2

IUPAC Name:

2-Methylcyclopentane-1,3-dione

Test material form:

solid: particulate/powder

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. For the stock solution 180.03 mg of test item was measured into 1 500 ml OECD medium. The suspension were stirred till complete dilution of test item. The stock solution was clear and colourless.The nominal concentration of stock solution was 120 mg/L.Preparation of test solutions:Seven 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 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):

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

Details on test organisms:

Test species: Pseudokirchneriella subcapitata(Korshikov)F.Hindák(formerly known asSelenastrum capricornutum)Scoure: UTEX The Culture Collcetion of Algae (USA)

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 nominal concentration of the stock solution was 120 mg/L. In the test the following nominal concentrations were applied: 120; 96; 60; 40; 32; 16 and 8 mg/L. The following concentrations were calculated from the measured values and were applied for the statistical evaluation in the test: 45.53; 41.54; 53.64; 38.49; 31.50; 15.90 and 7.82 mg test item/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 toxic property of test item was investigated at seven concentrations which were prepared by different dilutions of stock solution of test item. OECD medium was used for preparation and dilution of stock solution.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

22.45 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

24.94 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

30.5 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

not determinable

Effect concentrations 5

Duration:

72 h

Dose descriptor:

LOEC

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

not determinable

Details on results:

The values of LOEC and NOEC were also calculated by ToxRat® statistic software but the results were not conclusive or determinable.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Acute toxic effect of Methyl-cyclopentanedione was investigated in Freshwater Alga and Cyanobacteria, Growth Inhibition Test (according to OECD 201 guideline). The ErC50 was 30.50 mg/L at 72 h. According to the Council Regulation (EC) 440/2008 Methyl-cyclopentanedione is hazardous to the aquatic environment and classified into the third acute toxic hazardous category [GHS Acute aquatic hazard Category Acute III. – 72 h EC50 (for algae or other aquatic plants) > 10 mg/L but ≤ 100 mg/L].