(4-tert-butyl-2,6-dimethylphenyl)acetonitrile

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: Study performed in accordance with OECD Guideline and compliant with GLP criteria.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2003

Report date:

2003

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:

(4-tert-butyl-2,6-dimethylphenyl)acetonitrile

EC Number:

284-183-4

EC Name:

(4-tert-butyl-2,6-dimethylphenyl)acetonitrile

Cas Number:

84803-57-6

Molecular formula:

C14H19N

IUPAC Name:

2-(4-tert-butyl-2,6-dimethylphenyl)acetonitrile

Details on test material:

- Test substance name: 2,6-Dimethyl-4-tert.-butylbenzylcyanid
- Aggregate state: Solid powder
- Colour: White
- Homogeneity: Homogeneous
- Storage conditions: Ambient

Sampling and analysis

Analytical monitoring:

not required

Test solutions

Details on test solutions:

The test substance was added in the required amount to the test vessel with about 180 mL deionized water. The mixture was stirred for 22 ± 2 hours to obtain an optimal solution. Then synthetic medium was added, the pH-value was adjusted to 7.5 ± 0.5, the inoculum was added and the test was started.

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

Activated sludge f rom laboratory wastewater plant treating municipal sewage. The inoculum was washed, brought to a concentration of 5 g/L dry substance and aerated during the night. 50 mL were added to a total volume of 250 mL to obtain a concentration of 1 g/L dry substance in the test.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test conditions

Test temperature:

20 ± 0.5 °C

pH:

6.8-8

Dissolved oxygen:

- Before adding inoculum: 6.8 - 7.2 mg/L (pH corrected)
- After 3 hours inubation: 8.0

Nominal and measured concentrations:

- Nominal concentration: 0 (control) and 1000 mg/L

Details on test conditions:

- Test vessels: Erlenmeyer-vessel (nominal volume 250 mL)
- Test volume: 250 mL
- Synthetic medium: 8 mL/vessel 100-fold concentrated OECD medium
- Oxygen concentration during aeration: >2.5 mg/L
- Oxygen concentration immediately before measurement: >6.5 mg/L
- Duration of the measurement of oxygen consumption: 8 - 10 min

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

180 min

Dose descriptor:

other: EC20

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 2

Duration:

180 min

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

Details on results:

No change in oxygen consumption rate was observed at 1000 mg/L

Results with reference substance (positive control):

3-h EC20: ca. 3 mg/L
3-h EC50: ca. 22 mg/L