4-(2,5,6,6-tetramethylcyclohex-2-enyl)but-3-en-2-one

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:

1996

Report date:

1996

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:

3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one

EC Number:

204-846-3

EC Name:

3-methyl-4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-buten-2-one

Cas Number:

127-51-5

Molecular formula:

C14H22O

IUPAC Name:

3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one

Specific details on test material used for the study:

Name: Methyl Ionone Alpha Iso 60
Chemical name: 4-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3-Methyl-3-Buten-2-one
Description: Pale yellow liquid
Storage: Room temperature in the dark

Test solutions

Vehicle:

not specified

Details on test solutions:

The stock solution used in this study was prepared dispersing 0.18 g test substance (weighed out using the Mettler AE200 balance in 1.0 litre Elendt M7 medium to produce a 100 mg/l as α-iso isomer, 180 mg/l as commercial sample stock. The dispersion was achieved by mixing this stock using a high shear mixer for approximately 5 minutes at 12-14000 rpm. The test solutions were prepared by adding known volumes of stock to 2000 ml Elendt medium.
These test solutions were prepared 24 hours before the Daphnia were added to allow the test substance to equilibrate.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna were cultured in the laboratory according to the procedures described in SOP 019. Cultures were maintained in a synthetic medium with the same chemical composition and similar pH and dissolved oxygen concentration as that used to prepare test solutions. Culture medium consists of 800 ml Elendt M7 medium. The cultures are fed daily with cells of the green algae Chlorella vulgaris. Cultures are reset using 10 neonates, when they become gravid their numbers are reduced from 10 to 5 and the production of neonates results in their daily removal.

Study design

Test type:

static

Water media type:

freshwater

Total exposure duration:

48 h

Test conditions

Hardness:

The total hardness (as mg/l CaCO3) of selected solutions were measured at 0 and 48 hours using the appropriate methods. Total hardness (as mg/l CaCO3): 247 - 251

Test temperature:

The temperature of selected solutions were measured at 0 and 48 hours using the appropriate methods. Temperature: 19.0 - 21.5 °C

pH:

The pH of selected solutions were measured at 0 and 48 hours using the appropriate methods. pH: 7.4 - 7.6

Dissolved oxygen:

The dissolved oxygen concentration of selected solutions were measured at 0 and 48 hours using the appropriate methods. Dissolved oxygen concentration: 6.9 - 8.4 mg/l

Nominal and measured concentrations:

Nominal concentrations: 0.0, 1.8, 5.8, 10, 18 and 32 mg/l
Concentration of test substance based on mean measured TOC: 0.0, 1.8, 4.0, 7.3, 12 mg/l

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

3.7 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

1.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of Methyl Ionone Alpha Iso 60 to the freshwater cladoceran Daphnia magna was determined according to OECD Guideline 202 and EEC Directive 92/69/EEC L383 A.

Daphnia were exposed to a nominal range of concentrations 1.8 to 32 mg/l as the commercial sample. Analysis of the test substance, during the period of the test, remained relatively stable, however, the calculated concentrations based on TOC measurements were in the range of 0 - 41% of nominal.

The EC50s of the commercial sample based on mean measured TOC concentrations and calculated by the Binomial and Probit methods respectively, are given below:

48 hours: EC50 = 3.7 mg/l, 95% confidence limits 3.0 - 4.5
NOEC = 1.8 mg/l
Lowest conc. causing 100% mortality 7.3 mg/l