6,8-dimethylnona-3,5-dien-2-one

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: test performed according to OECD and GLP guidelines

Cross-reference

Cross-reference 1

Reason / purpose for cross-reference:

reference to same study

Cross-reference 2

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Title:

Unnamed

Year:

2002

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:

6,8-dimethylnona-3,5-dien-2-one

EC Number:

274-446-1

EC Name:

6,8-dimethylnona-3,5-dien-2-one

Cas Number:

70214-76-5

Molecular formula:

C11H18O

IUPAC Name:

6,8-dimethylnona-3,5-dien-2-one

Sampling and analysis

Analytical monitoring:

yes

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

9.3 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 2

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

2.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Any other information on results incl. tables

-

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Based on these data the nominal median effect concentration with respect to biomass production
(EbC50 (24-72 h) of DIMETHYLNONADIENON to Scenedesmus subspicatus was calculated to be
9.3 mg/l (95 % confidence limits: 7.8-11.0 mg/l).
The no-observed-effect concentration with respect to biomass production (NOEC, EbC0) was 2.5 mg/l.
100 % inhibition (EbC100) was observed at 80 mg/l.

Executive summary:

The median growth inhibiting concentration (ErC50 / EbC50) and the no-effect concentration (ErC0 / EbC0), based on growth rates and cell growth (algal biomass production), of DIMETHYLNONADIENON to the green alga Scenedesmus subspicatus were investigated over a period of 72 h. The nominal concentrations of DIMETHYLNONADIENON were 2.5, 5, 10, 20, 40 and 80 mg~, respectively.

Due to the limited water solubility of the test material the water accommodated fractions were tested. These were prepared by adding the respective concentrations as acetonic stock solutions to the empty glass vessels. After complete evaporation of the solvent the algal medium was added. Following a moderate stirring period for 24 h at room temperature the undissolved materials were removed by sterile filtration (0.45 um) to obtain sterile water accommodated fractions for the algal growth test. No chemical analyses of the test media were conducted.

With respect to algal growth rate inhibition the following effects as compared to the untreated controls were observed: 80 mg/l (99 %), 40 mg/l (88 %), 20 mg/l (46 %), 10 mg/l (15 %). No significant effects «10 % were observed at 5 and 2.5 mg/l.

Based on these data the nominal median effect concentration with respect to growth rate (ErC50 /24-72 h) of DIMETHYLNONADIENON to Scenedesmus subspicatus was calculated to be 19.8 mg/l (95 % confidence limits: 17.0-22.9 mg/l).

The no-observed-effect concentration with respect to growth rate (NOEC, ErC0) was 5 mg/l. 100 % inhibition (ErC100) was observed at 80 mg/l.

With respect to algal cell growth inhibition (biomass production) the following effects as compared to the untreated controls were observed:

80 mg/l (101 %),40 mg/l (99 %), 20 mg/l (87 %), 10 mg/l (56 %), 5 mg/l (16 %). No significant effects «10 % were observed 2.5 mg/l.

Based on these data the nominal median effect concentration with respect to biomass production (EbC50 / 24-72 h) of DIMETHYLNONADIENON to Scenedesmus subspicatus was calculated to be 9.3 mg/l (95 % confidence limits: 7.8-11.0 mg/l). The no-observed-effect concentration with respect to biomass production (NOEC, EbC0) was 2.5 mg/l. 100 % inhibition (EbC100) was observed at 80 mg/l.