2-hydroxy-3-methylcyclopent-2-enone

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

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

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-hydroxy-3-methylcyclopent-2-enone

EC Number:

201-303-2

EC Name:

2-hydroxy-3-methylcyclopent-2-enone

Cas Number:

80-71-7

Molecular formula:

C6H8O2

IUPAC Name:

2-hydroxy-3-methylcyclopent-2-en-1-one

Specific details on test material used for the study:

Test item: Methyl Cyclopentenolone
Common name of active ingredient (a.i): Methyl cyclopentenolone
CAS number of a.i: 80-71-7
Molecular weight of a.i.: 112 g.moL-1
Molecular formula of a.i.: C6H8O2
Received on: 12/Dec/2017
Bioagri Laboratórios Ltda. code: AGR-0921/17
Batch number: D270001706002
Physical state: White, crystal powder
Manufacture date: 08/Jun/2017
Expiry date: 07/Jun/2018

Test solutions

Details on test solutions:

The primary stock solution used in the range-finding test was prepared by dissolving 10 mg of the test substance in 40 mL of dilution water – M4 and the total volume was completed to 100 mL, resulting in a concentration of 100 mg.L-1. The secondary stock solutions of the 10; 1 and 0,1 mg.L-1 were prepared by dilutions of the primary stock solution.

The stock solution used in the definitive test was prepared by dissolving 50 mg of the test substance in 40 mL of dilution water – M4 and the total volume was completed to 500 mL, resulting in a concentration of 100 mg.L-1.

The test solutions were prepared from dilutions of the stock solutions.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Test System:
The test system used for this study is described below, according to Straus (1820):
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Branchiopoda
Order: Cladocera
Family: Daphniidae
Genus: Daphnia
Species: Daphnia magna
Young Daphnia magna ≤ 24 hours old were obtained from the culture kept at the Ecotoxicology Laboratory, maintenance and cultivation records are archived at BIOAGRI.

Test System Justification:

Daphnia magna is the preferred test species as cited in the Guideline OECD 202 (2004).
As these organisms are very sensitive and easy to breed under laboratory conditions, they are useful for evaluating the acute and chronic toxicity of chemical substances and environmental samples.

Origin of the Test System:

The test system Daphnia magna was obtained from the CAROLINA BIOLOGICAL SUPPLY COMPANY - Burlington, North Carolina (USA) and maintained as a stock culture at BIOAGRI.

Test System Obtainment:

Nearly 24 hours before the Acute Toxicity Test started, Daphnia with eggs were isolated in crystallizing dishes and fed with algae suspension. In the following morning, the newly born Daphnia, aged ≤ 24 hours, were separated from the adults and used in the test.

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Test conditions

Hardness:

174.24 to 185.2 mg.L-1 CaCO3

Test temperature:

20.1 to 20.2°C

pH:

7.7 to 7.8

Dissolved oxygen:

8.0 to 8.1 mg.L-1

Nominal and measured concentrations:

In the range-finding test the exposure conditions:
Nominal used concentrations: control; 0.01; 0.1; 1; 10 and 100 mg.L-1;
In the definitive test the exposure condition:
Nominal used concentrations: control; 6.5; 13; 25; 50 and 100 mg.L-1;

Details on test conditions:

In the range-finding test the exposure conditions were:

a) Total number of organisms per each tested concentration or control: 10;
b) Number of replicates per each tested concentration and control: 2;
c) Number of organisms per test container: 5;
d) Volume: 15 mL of test solution per test container, 3 mL to each Daphnia;
e) The organisms were distributed randomly in the test container. Firstly, three organisms were placed in each test container and, finally, two organisms were added to the container;
f) Nominal used concentrations: control; 0.01; 0.1; 1; 10 and 100 mg.L-1;
g) Temperature of the test solutions: 20.0 to 20.3°C;
h) Photoperiod: 16 hours of light and 8 hours of dark;
i) Parameters evaluated: immobility after 24 and 48 hours; and still animals were considered unable to swim for a period of 15 seconds of observation after mild agitation of the flasks.

In the definitive test the exposure conditions were:

a) Total number of organisms per each tested concentration or control: 20;
b) Number of replicates per each tested concentration and control: 4;
c) Number of organisms per test container: 5;
d) Volume: 15 mL of test solution per test container, 3 mL to each Daphnia;
e) The organisms were distributed randomly in the test container. Firstly, three organisms were placed in each test container and, finally, two organisms were added to the container;
f) Nominal used concentrations: control; 6.5; 13; 25; 50 and 100 mg.L-1;
g) Temperature of the test solutions: 20.2 to 20.3°C;
h) Photoperiod: 16 hours of light and 8 hours of dark;
i) Parameters evaluated: immobility after 24 and 48 hours; and still animals were considered unable to swim for a period of 15 seconds of observation after mild agitation of the flasks;
j) Analytical determination: content dissolved oxygen, pH of the test solutions and the test substance concentration were determined at the beginning of the test and after 48 hours.

Reference substance (positive control):

yes

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

43.74 mg/L

Remarks on result:

other: (95% confidence limits = 35.74 to 53.53 mg.L-1)

Effect concentrations 2

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

93.89 mg/L

Remarks on result:

other: (95% confidence limits was not determined)

Details on results:

In the range-finding test, In 48 hours of exposure, the lowest concentration that caused 100% immobilization to the organisms was 100 mg.L-1 and the highest concentration that caused 0% immobilization to the organism was 1 mg.L-1.

The 24 and 48-hours EC50 values of the product Methyl Cyclopentenolone were 93.89 mg.L-1 (95% confidence limits was not determined) and 43.74 mg.L-1 (95% confidence limits = 35.74 to 53.53 mg.L-1), respectively.

In the definitive test the highest tested concentration that did not cause acute effect (immobility) to the organisms after 48 hours was 13 mg.L-1. The lowest concentration that caused 100% immobility was 100 mg.L-1.

Results with reference substance (positive control):

The 24-hours EC50 value of the reference substance (potassium dichromate) was 1.03 mg.L-1 (95% confidence limits = 0.91 to 1.17 mg.L-1), showing the sensitivity of the test system (ISO 6341 / OECD 202, 2004).

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48-hours EC50 value of Methyl Cyclopentenolone was 43.74 mg.L-1 (95% confidence limits = 35.74 to 53.53 mg.L-1).