2-isobutyl-4-methyltetrahydro-2H-pyran-4-yl acetate

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD guideline

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 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-isobutyl-4-methyltetrahydro-2H-pyran-4-yl acetate

EC Number:

942-380-9

Cas Number:

131796-64-0

Molecular formula:

C12H22O3

IUPAC Name:

2-isobutyl-4-methyltetrahydro-2H-pyran-4-yl acetate

Details on test material:

- Name of test material (as cited in study report): pyranyl acetate pure
- Physical state: Liquid/ colorless to yellowish; clear
- Analytical purity: 99.0 corr. area-%
- Lot/batch No.: ZH 146
- Expiration date of the lot/batch: Dec 2015
- Water solubility: 814 mg/L at 20 °C
- Stability under test conditions: stable
- Storage condition of test material: Ambient at room temperature

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
Direct addition by initial weight into the test flasks. The test substance was weighed in the required amounts for the test concentrations directly to the test
vessels.

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Laboratory culture:
Origin: Municipal wastewater treatment plant of Mannheim, Germany
Collection of the test system: 10 Aug 2015
Arrival in the test facility: 10 Aug 2015
- Preparation of inoculum for exposure: After arrival of the activated sludge suspension in the test facility the suspension was sieved
with a fine woven mesh (mesh size about 1 mm). This suspension was pre-aerated over night at room temperature. At the next day the sludge suspension was washed once with drinking water and the suspension was adjusted to 3 g/L Dw.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Test temperature:

20.1 – 20.4 °C

Nominal and measured concentrations:

1000, 500, 250, 125, 62.5 mg/L as nominal concentration based on test substance without correction of purity and blank controls.

Details on test conditions:

TEST SYSTEM
- Test vessel: Glas-beakers (nominal volume 1L)
- Test volume: 500 mL
- Type (delete if not applicable): closed
- No. of vessels per concentration (replicates): 3 replicates for each test substance concentration
- No. of vessels per control (replicates): 6 replicates for the control
- Sludge concentration in the test vessel: 1.5 g/L Dw
- Oxygen concentration during aeration: > 2 mg/L
- Oxygen concentration immediately before measurement: About 7 mg/L
- Duration of the measurement of oxygen consumption: about 8 - 10 min

TEST MEDIUM / WATER PARAMETERS
- Synthetic medium: 16 mL/test vessel of 100-fold concentrated OECD

OTHER TEST CONDITIONS
- Adjustment of pH: no

Reference substance (positive control):

yes

Remarks:

3,5 dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

580 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 552.4/618.5

Effect concentrations 2

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

730 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 707.0/757.9

Effect concentrations 3

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 4

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

Two deviations from the study plan and the test guidelines was realized.
1. The start value of oxygen content for measurement of oxygen consumption was lower
than 7 mg/L
2. The measuring time for oxygen consumption was < 8 minutes in test assay TS15
An influence to the results of this study can be excluded.

Results with reference substance (positive control):

- Results with reference substance valid? yes
The EC50 of 3,5-dichlorophenol was 7.0 mg/L

Reported statistics and error estimates:

The consumption rates were used for the determination of the ECx by the probit method based
on Finney [1] with the software TOXRAT Professional 2.10 [2]. The effect concentrations were
given with an accuracy of 2 significant digits.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes