Reaction mass of 6-butyl-3,6-dihydro-2,4-dimethyl-2H-pyran and 2-butyl-3,6-dihydro-4,6-dimethyl-2H-pyran and 2-butyltetrahydro-6-methyl-4-methylene-2H-pyran

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

Study period:

24 June - 03 August 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2016

Report date:

2016

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

There were no deviations from the study plan.

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Version / remarks:

There were no deviations from the study plan.

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-butyl-3,6-dihydro-4,6-dimethyl-2H-pyran

EC Number:

246-099-6

EC Name:

2-butyl-3,6-dihydro-4,6-dimethyl-2H-pyran

Cas Number:

24237-01-2

Molecular formula:

C11H20O

IUPAC Name:

2-butyl-4,6-dimethyl-3,6-dihydro-2H-pyran

Constituent 2

Reference substance name:

6-butyl-3,6-dihydro-2,4-dimethyl-2H-pyran

EC Number:

246-098-0

EC Name:

6-butyl-3,6-dihydro-2,4-dimethyl-2H-pyran

Cas Number:

24237-00-1

Molecular formula:

C11H20O

IUPAC Name:

6-butyl-2,4-dimethyl-3,6-dihydro-2H-pyran

Constituent 3

Reference substance name:

2-butyltetrahydro-6-methyl-4-methylene-2H-pyran

EC Number:

246-101-5

EC Name:

2-butyltetrahydro-6-methyl-4-methylene-2H-pyran

Cas Number:

24237-02-3

Molecular formula:

C11H20O

IUPAC Name:

2-butyl-6-methyl-4-methylenetetrahydro-2H-pyran

Specific details on test material used for the study:

Material Identification (as stated in the report) : Gyrane
Appearance: Colourless to pale yellow liquid
Batch: SC00016010
Expiry date: 27 August 2017

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

no

Details on test solutions:

Preparation of test solutions started with a loading rate of 100 mg/L applying a three-day period of magnetic stirring to ensure maximum dissolution of the test item in test medium. Thereafter, the resulting mixture was allowed to stabilize for approximately one hour (rangefinding: 73 min, final: 64 min). Subsequently, the Saturated Solution (SS) was siphoned off and used as the highest test concentration. Lower concentrations were prepared by subsequent dilutions of the highest concentration in test medium. Due to the light sensitivity of the test item, preparation of test solutions was performed under dimmed light and used glassware was wrapped in aluminum foil. All final test solutions were clear and colourless.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Daphnia magna (Crustacea, Cladocera) (Straus, 1820), at least third generation, obtained by a cyclical parthenogenesis under specified breeding conditions. For the test selection of young daphnids with an age of
< 24 hours, from parental daphnids older than two weeks.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Nominal and measured concentrations:

The actual concentrations at the start of the test were 1.7, 3.8, 8.0, 19 and 34 mg/L in 4.6, 10, 22, 46 and 100% of the SS respectively. During the exposure period, the measured concentration remained stable, i.e. were at 88-116% of initial at the end of the test. Based on these results, the initially measured concentrations were used to determine the effects parameters.

Details on test conditions:

A final test was performed based on the results of a preceding range-finding test. Twenty daphnids per group (5 per replicate, quadruplicate) were exposed to an untreated control and to 4.6, 10, 22, 46 and 100% of the SS. The total exposure period was 48 hours and samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test. The exposure was performed in dark and airtight closed vessels.

Reference substance (positive control):

no

Results and discussion

Effect concentrations

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

4.6 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

During the exposure period, the measured concentrations remained stable, i.e. were at 88-116% of initial at the end of the test. Based on these results, the initially measured concentrations were used to determine the effects parameters.

Any other information on results incl. tables

No immobility was observed in the controls and the two lowest test concentrations, except for one daphnid exposed to 1.7 mg/L at the end of the test. After 24 hours of exposure, observed immobility increased with increasing concentration at the three highest concentrations, ranging from 60 to 100%. At the end of the test, 95% of organisms exposed to 8.0 mg/L were immobile and effects at the two highest concentrations were complete. Microscopic observations at the end of the test confirmed that no test item was attached to organisms exposed to 8.0 mg/L. The responses recorded in this test allowed for reliable determination of an EC50.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48h-EC50 was 4.6 mg/L based on measured exposure concentrations (95% confidence interval between 2.7 and 5.9 mg/L).

Executive summary:

Acute Toxicity Study in Daphnia magna with GYRANE. The study procedures described in this report were based on the OECD guideline No. 202, 2004. In addition, the procedures were designed to meet the test methods of the Commission Regulation (EC) No 440/2008, Part C.2, 2008 and the OECD series on testing and assessment number 23, 2000. The batch of GYRANE tested was a colourless to pale yellow liquid mixture and not completely soluble in test medium at the loading rate initially prepared. A Saturated Solution (SS) was prepared at 100 mg/L and used as the highest test concentration. Lower test concentrations were prepared by subsequent dilutions of the SS in test medium. Due to the light sensitivity of the test item, preparation of test solutions was performed under dimmed light and used glassware was wrapped in aluminum foil. All final test solutions were clear and colourless. A final test was performed based on the results of a preceding range-finding test. Twenty daphnids per group (5 per replicate, quadruplicate) were exposed to an untreated control and to 4.6, 10, 22, 46 and 100% of the SS. The total exposure period was 48 hours and samples for analytical confirmation of exposure concentrations were taken at the start and at the end of the test. The exposure was performed in dark and airtight closed vessels. Samples taken from all test concentrations were analysed. The actual concentrations at the start of the test were 1.7, 3.8, 8.0, 19 and 34 mg/L in 4.6, 10, 22, 46 and 100% of the SS, respectively. During the exposure period, the measured concentration remained stable, i.e. were at 88-116% of initial at the end of the test. Based on these results, the initially measured concentrations were used to determine the effects parameters. The study met the acceptability criteria prescribed by the study plan and was considered valid. The 48h-EC50 was 4.6 mg/L based on measured exposure concentrations (95% confidence interval between 2.7 and 5.9 mg/L).