Benzeneacetic acid, 4-(cyclopropylcarbonyl)-.alpha.,.alpha.-dimethyl-, ethyl ester

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

February 05 to March 25, 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study performed according to international guidelines.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Test guideline 2

Qualifier:

according to guideline

Guideline:

ISO 8192 (Water quality - Test for inhibition of oxygen consumption by activated sludge for carbonaceous and ammonium oxidation)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

4-(Cyclopropylcarbonyl)-α,α-dimethyl-ethyl ester benzeneacetic acid

EC Number:

605-546-9

Cas Number:

169280-10-8

Molecular formula:

C16 H20 O3

IUPAC Name:

4-(Cyclopropylcarbonyl)-α,α-dimethyl-ethyl ester benzeneacetic acid

Details on test material:

- Purity: 99.0%
- Bacth: Dest. 3-1, dated April 07, 1997 from PT/TTF
- Expiration date of the lot/batch: April 07, 1999

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Origin: Sewage treatment plant at Frankfurt am Main-Sindlingen
- Amount used: 450 ml/l sludge suspension
- Content of suspended solids: 20.4 g/l (centrifuged wet matter), 3.56 g/l (dry matter)
- Content in the final test volume: 1.6 g/l (dry matter)
- Storage: The concentrated inoculum suspension was aerated over 3 days.

Study design

Test type:

not specified

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Test temperature:

19.3 - 20.8 °C

pH:

8.3 - 8.5 after the incubation of the test batches

Dissolved oxygen:

After 3h of incubation:
Control: Start values: 6.7 -7.2 mg/l, end values: 3.1-3.7 mg/l
Reference substance: Start values: 7.4 -8.3 mg/l, end values: 3.9-6.7 mg/l
Test concentrations: Start values: 6.6 -7.6 mg/l, end values: 3.2-4.7 mg/l

Nominal and measured concentrations:

Nominal concentrations: 250, 500 and 1000 mg/l

Details on test conditions:

TEST SYSTEM
- Incubation vessel: Glassbottles (diam. 60 mm, height 170 mm) of a total volume = 480 ml with magnetic stirrer bars.
- Test volume: 200 ml each batch
- Temperature control: performed by a water circulating thermostate
- Aeration: 50 L/h, only during the incubation period
- Oxygen measurements: with oxygen electrodes

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Effect concentrations 2

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Effect concentrations 3

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Details on results:

A significant inhibition could not be observed. The EC values were above the highest tested concentration.

Results with reference substance (positive control):

The EC50 of the reference substance was between 5 and 30 mg/l and amounted to 24 mg/l.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC50 of the test substance to activated sludge is greater than 1000 mg/l according to valid international guidelines.