1,3-Cyclopentanedione, 2-[2-(3,4-dihydro-6-methoxy-1(2H)-naphthalenylidene)ethyl]-2-methyl-

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

Report date:

2015

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

Constituent 1

Reference substance name:

2-[(2E)-2-(6-Methoxy-3,4-dihydronaphthalen-1(2H)-ylidene)ethyl]-2-methylcyclopentane-1,3-dione

EC Number:

618-321-5

Cas Number:

899-79-6

Molecular formula:

C19H22O3

IUPAC Name:

2-[(2E)-2-(6-Methoxy-3,4-dihydronaphthalen-1(2H)-ylidene)ethyl]-2-methylcyclopentane-1,3-dione

Test material form:

solid: crystalline

Details on test material:

Test item: Methyl-secodione
CAS number: 899-79-6
Molecular formula: C19H22O3
Batch number: L4B021N
Physical state: Solid, crystalline powder
Colour: Beige
Storage: At room temperíture, dry place

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Details on test solutions:

For the stock solution 200.09 mg of test item was measured into 2 000 ml OECD medium. The suspension was stirring for 24 hours. After it the suspension was filtered. The first 100 ml filtrate was disposed. The concentration of the filtrate (stock solution) was determined by validated HPLC method. The measured concentration of the test item in stock solution was 9.59 mg/L.
Three replicates were prepared at every test and six at the control level. The vessels contained 75 ml test media.

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 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.
The vessels were kept in incubator at 21 ± 2 °C with continuous illumination.

pH:

The pH was measured at the beginning and at the end of the test.
At the beginning of the test the measured mean values varied in the range of 6.94 - 7.51.
At the end of the test the measured mean values varied in the range of 8.08 - 8.91.

Nominal and measured concentrations:

In the test the following nominal concentrations were applied: 9.59; 8.79; 7.99; 7.19; 6.39; 3.20; and 1.60 mg/L.
In the test the following measured mean concentrations were applied: 3.95; 3.63; 3.25; 2.98; 2.60; 1.28 and 0.67 mg/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 vessels were closed with rubber plugs with a filter for ensuring the proper air exchange.
The initial alga concentration was 4 941 cells/ml.

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

2.6 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

4.31 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

< 2.6 mg/L

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

The values of LOEC and NOEC were also determined by ToxRat® statistic software.
The results of the test showed that the test item had got toxic effect for the growth rate of Pseudokirchneriella subcapitata.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

According to this Freshwater Alga and Cyanobacteria, Growth Inhibition Test for methyl-secodione the results indicated that the test item is hazardous to the aquatic environment [GHS Acute aquatic hazard Category Acute II. – 72 hr EC50 (for algae or other aquatic plants) > 1 mg/L but ≤ 10 mg/L].