2-[2-(3,4-dihydro-6-methoxy-1(2H)-naphthylidene)ethyl]-2-ethylcyclopentane-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:

other: Well documented study according to international accepted guidelines and GLP compliant.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2015

Report date:

2015

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-[2-(3,4-dihydro-6-methoxy-1(2H)-naphthylidene)ethyl]-2-ethylcyclopentane-1,3-dione

EC Number:

212-705-2

EC Name:

2-[2-(3,4-dihydro-6-methoxy-1(2H)-naphthylidene)ethyl]-2-ethylcyclopentane-1,3-dione

Cas Number:

850-92-0

Molecular formula:

C20H24O3

IUPAC Name:

2-ethyl-2-[2-(6-methoxy-3,4-dihydronaphthalen-1(2H)-ylidene)ethyl]cyclopentane-1,3-dione

Test material form:

solid: crystalline

Details on test material:

Test item: Ethyl-secodion
CAS No.: 850-92-0
Batch No.: L49030N
Physical state: Solid, crystalline powder
Colour: Beige
Storage: At room temperature, dry place

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Details on test solutions:

The preparation of the test solution was based on the preliminary non-GLP conform range finding test.

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)

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

72 h

Test conditions

Test temperature:

The temperature inside the incubator at the test vessels was measured and registered continuously. Throughout the test the temperature was nearly constant.

pH:

The measured mean pH values at the beginning of the test varied in the range of 7.24 - 7.54.
The measured mean pH values at the end of the test varied in the range of 7.38 - 7.67.

Nominal and measured concentrations:

In the test the following nominal concentrations were applied: 5.49; 5.03; 4.58; 4.12; 3.66; 1.83; and 0.92 mg/L.
The mean values of measured concentrations were: 3.23; 2.95; 2.62; 2.42; 2.15; 1.06 and 0.54 mg test item/L.

Details on test conditions:

The toxic property of test item was investigated at seven concentrations which were prepared by different dilutions of the saturated solution of test item. At each concentration level three replicates were used.
The initial alga concentration was 4 963 cells/ml. The vessels were kept in incubator at 21 ± 2 °C with continuous illumination.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

2.7 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: For yield

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

2.89 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: For yield

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

3.31 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: For yield

Details on results:

The EC50 for specific growth rate (ErC50) was not determinable so the classification was made on the base of EC50 for yield (EyC50).
The values of LOEC and NOEC were calculated by ToxRat® statistic software but the results were not conclusive or determinable.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In this Freshwater Alga and Cyanobacteria, Growth Inhibition Test for Ethyl-secodion (CAS No. 850-92-0) the results indicated that the test item is hazardous to the aquatic environment and classified into the second acute toxic hazardous category [GHS Acute aquatic hazard Category Acute II. – 72 hr EC50 (for algae or other aquatic plants) > 1 mg/L but ≤ 10 mg/L].