p-methoxybenzyl acetate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000-06-15 and 2000-07-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Municipal sewage treatment plant, D-31137 Hildesheim
- Pretreatment: The activated sludge was filtered with folded filter. The first 200 mL of the filtrate were not used. The second filtrate effluent from the domestic waste water was used to initiate inoculation.
- Initial cell/biomass concentration: 4.8 x 10E+7 CFU/L

Duration of test (contact time):

28 d

Initial conc.:

4 mg/L

Based on:

test mat.

Initial conc.:

8.16 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral nutrient solution according to OECD 301 D
- Test temperature: 20.5 - 21 °C
- Aeration of dilution water: Yes
- pH: test item (begin: 7.2, end: 7.25), inoculum control (begin: 7.44, end: 7.35), functional control (begin: 7.34, end: 7.15), toxicity control (begin: 7.12, end: 7.19)

TEST SYSTEM
- Culturing apparatus: BOD vessels with glass stoppers (volume 300 mL)
- Number of culture flasks/concentration: 5 x 2
- Measuring equipment: pH-Meter, "CORNING" pH 240; Oximeter, "WTW" Oxi 530

SAMPLING
- Sampling frequency: on day 0, 7, 14, 21 and 28

CONTROL AND BLANK SYSTEM
- Inoculum blank: only inoculum
- Functional control: reference item and inoculum
- Toxicity control: test and reference item and inoculum (2 mg/L)

Reference substance:

acetic acid, sodium salt

Test performance:

The validity criteria were fulfilled. The percentage degradation of the functional control reached the pass level of 60 % on day 6. The oxygen depletion in the inoculum control was 1.51 mg dissolved oxygen/L after 28 d. The residual concentration of oxygen in the test bottles did not fall below 0.5 mg/L. The difference of extremes of replicate values of removal of the test item at the end of the test was less than 20 % and the temperature was in the range of 20 - 21 °C.

Key result

Parameter:

% degradation (O2 consumption)

Value:

78

Sampling time:

21 d

Parameter:

% degradation (O2 consumption)

Value:

70

Sampling time:

28 d

Details on results:

The test item reached the 10 % level after 1 day. The pass level of a biodegradation > 60 % was reached after 6 days. In the 10-d-window a biodegradation rate of 76 % and the plateau was reached. The biodegradation came to a maximum of 78 % after 21 days.

Results with reference substance:

The functional control reached the pass level > 60 % by day 6. After 14 days a maximum biodegradation rate of 79 % and the plateau was reached.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

A biodegradation rate of 78 % after 21 days was reached. The test substance must be regarded to be readily biodegradable.

Executive summary:

The ready biodegradability in the Closed Bottle Test was determined with a non-adapted activated sludge for the test item. The test item concentration selected as appropriate was 4 mg/L. The degradation was followed by measuring the oxygen concentrations and is expressed as the percentage BOD and was calculated for each oxygen analysis. The toxicity control reached a biodegradation rate of 78% within 14 days and achieved a maximum of 79% after 28 days. The test item reached the 10% level after 1 day. The pass level of a biodegradation greater than 60% was reached after 6 days. In the 10 -d-window a biodegradation rate of 76% and the plateau was reached. The biodegradation came to a maximum of 78% after 21 days. The test item must be regarded to be readily biodegradable in the 10 -d window.

Description of key information

In a closed bottle test the test item showed 78 % biodegradation after 21 days, and 10 -d window met, therefore it was considered to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The ready biodegradability in the Closed Bottle Test was determined with a non-adapted activated sludge for the test item. The test item concentration selected as appropriate was 4 mg/L. The test item reached the 10 % level after 1 day. The pass level of a biodegradation greater than 60 % was reached after 6 days. In the 10 -d-window a biodegradation rate of 76 % and the plateau was reached. The biodegradation came to a maximum of 78 % after 21 days. The test item must be regarded to be readily biodegradable in the 10 -d window.