Benzyl propionate

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:

from 2001-08-15 to 2001-11-29

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, Germany
- 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.
- Concentration of sludge: 10E+4 - 10E+6 colony forming units/L (CFU/L)

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

test mat.

Initial conc.:

4.64 other: mg O2/L

Based on:

other: 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 — 21 °C
- pH: at begin: 7.00 - 7.11 (test vessels); at end: 5.05 - 6.63 (test vessels)
- pH adjusted: no
- Aeration of dilution water: yes

TEST SYSTEM
- Culturing apparatus: BOD bottles with glass stoppers (volume 300 mL)
- Number of culture flasks/concentration: 10
- Method used to create aerobic conditions: One day before the test started the demineralized water for the test medium was aerated until oxygen saturation.
- Measuring equipment: pH-Meter, "CORNING" pH 240, Oximeter, "WTW" Oxi 530

SAMPLING
- Sampling frequency: weekly

CONTROL AND BLANK SYSTEM
- Inoculum blank: mineral medium containing only inoculum
- Toxicity control: mineral medium containing test item, reference item and inoculum

Reference substance:

acetic acid, sodium salt

Preliminary study:

none

Key result

Parameter:

% degradation (O2 consumption)

Value:

72

Sampling time:

28 d

Remarks on result:

other: On day 21, reached 72%

Details on results:

65 % degradation was reached within 7 days, 58 % within 14 days and 72 % within 21 days. Based on analysis of the weekly samples the 14-day window was passed. In the toxicity control containing both test and reference item 69 % degradation occurred within 14 days. The degradation of the reference item was not inhibited by the test item.

Results with reference substance:

The functional control reached the pass level > 60 % after 5 days. After 14 days a biodegradation rate of 85 % was reached.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The test item must be regarded to be readily biodegradable in the 10-d-window and after 28 days.

Executive summary:

The ready biodegradability in the Closed Bottle test was determined with a non-adapted activated sludge for the test item over a period of 28 days according to OECD 301D. The test item concentration selected as appropriate was 2.0 mg/L, corresponding to a ThOD of 2.32 mg O2/mg test item and 4.64 mg O2/L in the test vessel. The degradation was followed by measuring the oxygen concentrations. The pass level of a biodegradation > 60 % was reached after 7 days and in the 10-d-window. The biodegradation came to a maximum of 72 % after 21 days. At this point of time the plateau was reached. The test item must be regarded to be readily biodegradable in the 10-d-window and after 28 days.

Description of key information

The biodegradation came to a maximum of 72 % after 21 days. The test item must be regarded to be readily biodegradable in the 10-d-window and after 28 days.

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 over a period of 28 days according to OECD 301D. The test item concentration selected as appropriate was 2.0 mg/L, corresponding to a ThOD of 2.32 mg O2/mg test item and 4.64 mg O2/L in the test vessel. The degradation was followed by measuring the oxygen concentrations. The pass level of a biodegradation > 60 % was reached after 7 days and in the 10-d-window. The biodegradation came to a maximum of 72 % after 21 days. At this point of time the plateau was reached. The test item must be regarded to be readily biodegradable in the 10-d-window and after 28 days.