Benzeneacetic acid, .alpha.,.alpha.-dimethyl-, ethyl ester

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Start of the experimental part: 17.09.1997 - End of the experimental part: 16.10.1997

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: 1a : GLP guideline study

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 301 F (Ready Biodegradability: Manometric Respirometry Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Test guideline 3

Qualifier:

according to guideline

Guideline:

ISO DIS 9408 (Ultimate Aerobic Biodegradability - Method by Determining the Oxygen Demand in a Closed Respirometer)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

α,α-Dimethyl-ethyl ester benzeneacetic acid

EC Number:

608-307-7

Cas Number:

2901-13-5

Molecular formula:

C12 H16 O2

IUPAC Name:

α,α-Dimethyl-ethyl ester benzeneacetic acid

Details on test material:

Substance name: Benzeneacetic acid, α,α-dimethyl-, ethyl ester
Chemical name: 2-Methyl-2-phenylpropionsäureethylester
Synonyms: EDMPA
Code: HOE CG 0530 0Y ZD00 0001
Expiry date: March 18, 2000
Purity: 99.8%

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Origin: Sewage treatment plant at Frankfurt am Main-Sindlingen
Preparation of the suspension: Sediment from the activated sludge was washed two times by centrifuging and resuspending in mineral medium.
Amount: 10 ml/l sludge suspension
Content of sludge sediment: 16 g/L
Content of suspended solids: 2.4 g/L (dry matter)
Content in the final test volume: 24 mg/L (dry matter)
Pretreatment: Aerated for 7 days

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

38.5 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

38.75 mg/L

Based on:

test mat.

Initial test substance concentration 3

Initial conc.:

39.5 mg/L

Based on:

test mat.

Initial test substance concentration 4

Initial conc.:

40 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

Incubation temperature: thermostatically controlled at 22°C ± 1°C. During the test period the temperature remained in the range between 21.8°C and 22.2°C.
Reaction vessel: closed system. 500 ml glass bottles with magnetic stirrers.
The evolved CO2 was trapped in an adsorption reagent in internal side chambers of the vessels. The second connected vessels were the electrolytic chambers for oxygen production and the third connected vessels contained capillaries for the electronic detection of the differences in gas pressure.

COD-content of the test substance: 2496.5 mg/g [O2] (calculated from the empirical formula)
Concentration of the test substance : 39.5 mg/l, 38.5 mg/l, 38.75 mg/l and 40.0 mg/l

COD-content in the test system : 98.61 mg/l [O2], 96.12 mg/l [O2], 96.74 mg/l [O2] and 99.86 mg/l [O2] (calculated)

Reference substance

Reference substance:

benzoic acid, sodium salt

Remarks:

pH=7.1, calculated COD= 3330.8 mg O2/L, concentration used: 99.92 mg/l

Results and discussion

% Degradation

Parameter:

% degradation (O2 consumption)

Value:

< 20

Sampling time:

28 d

Remarks on result:

other: Mean results in 4 parallel batches reached less than 20%.

Details on results:

Biodegradation in % of the COD within 28 days:
- Test A, COD/thOD=98.61 mgO2/l: 0%
- Test B, COD/thOD=96.12 mgO2/l: 0%
- Test C, COD/thOD=96.74 mgO2/l: 38%
- Test D, COD/thOD=99.86 mgO2/l: 0%
- Mean value = 10%

BOD5 / COD results

Results with reference substance:

The degradation of the reference substance caused an oxygen consumption of more than 60% of the theoretical maximum within 14 days.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance is not readily biodegradable under the conditions of this test. Significant biodegradation was not detected.