Reaction mass of 3,5,5-Trimethylhexanoyl chloride and Methyl 3-methyl-2-butenoate

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1996-05-09 to 1996-06-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed acc. to Guideline, is well documented and run under GLP

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 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

4-methyl-6-(2,4,4-trimethylpentyl)-2H-pyran-2-one

EC Number:

610-555-6

Cas Number:

50650-75-4

Molecular formula:

C14 H22 O2

IUPAC Name:

4-methyl-6-(2,4,4-trimethylpentyl)-2H-pyran-2-one

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method:
Concentration of stock solution: 20000 mg/L
Preparation of stock solution:
20000mg of test substance was weighed in together with 800mL water.
Solution was stirred for 5 min. twice at 19°C
Afterwards it was treated 15min. twice by ultrasound
The pH was adjusted from 4.3 to 7.5 by using 10mol/L NaOH-solution.
The solution was then treated with ultrasound (15min) and was stirred (5min).
The test substance was only partially solublized. It was then filtrated and brought up to 1L.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

Activated sludge was used.
source: municipal waste treatment plant Frankfurt/Sindlingen
Treatment: According to the guideline. The bacterial culture was adapted neither to the test substance nor to the reference substance before the test.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Remarks on exposure duration:

The exposure period was reduced to 30 Min because of the volatility of the test substance. Results are related to the analytical measurements.

Test conditions

Test temperature:

19.7 - 20.3°C

pH:

7.3 - 7.4

Nominal and measured concentrations:

Test was run in duplicates. Measured test concentrations were 5.0, 10.2, 26.5, 37.2, 47., 84.7, 218.6 and 593.0

Details on test conditions:

Because of the high volatility of the test substance in aqueous solution, the incubation period was shortened to 30 minutes. Initially and after each test at the end the test substance content was determined via the dissolved organic carbon (DOC). Based on the analytical results the stability of the test concentrations cannot be guaranteed over the test time. At some concentration levels, a significant decrease (> 20%) of the test substance during the test period was found. Therefore, all concentration data refer to the values ​​which were analytically determined directly after recording the activity curves.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorphenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

36 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks on result:

other: confidence interval 15 - 67 mg/L

Effect concentrations 2

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

337 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks on result:

other: confidence interval 162 - 1597 mg/L

Effect concentrations 3

Duration:

30 min

Dose descriptor:

other: EC80

Effect conc.:

> 555 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The calculated EC50 is 360 mg/L wiith a confidence intervall of 173-1706 mg/L.