Ethyl 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:

1991-12-12 to 1992-01-09

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: According to OECD 301 D (1981) and GLP, no toxicity control performed

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Stored in darkness

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Effluent from the waste water treatment plant KA Hochdahl, Germany

Duration of test (contact time):

28 d

Initial conc.:

2 mg/L

Based on:

test mat.

Initial conc.:

5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral medium
- Test temperature: 20±1°C

TEST SYSTEM
- Culturing apparatus: Conical shoulder bottles
- Number of culture flasks/concentration: Two flask per concentration, two flask per reference and inoculum control, oxygen control with one flask
- Measuring equipment: Jodometric determination of oxygen.

CONTROL AND BLANK SYSTEM
- Inoculum blank: Yes
- Abiotic sterile control: No
- Toxicity control: No
- Other: Oxygen control (medium without test substance and inokolum) and reference control (sodium benzoate)

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

68

Sampling time:

28 d

Remarks on result:

other: test concentration: 2 mg/L

Key result

Parameter:

% degradation (O2 consumption)

Value:

66

Sampling time:

28 d

Remarks on result:

other: test concentration: 5 mg/L

Details on results:

No toxicty control was included. However, it could be observed that the substance had no inhibitory effects to the microorganisms up to a test concentration of 5 mg/L.

Results with reference substance:

In parallel preparations with reference substance, a biodegradation of 90% was achieved within 28 days.

DO, mean after n days in [mg O2/L]
	7	14	21	28
Test substance I* [c=2 mg/L]	7.11	6.66	6.39	6.47
Test substance II* [c=5 mg/L]	5.30	3.39	3.04	2.65
Reference substance*	6.41	6.38	6.18	6.17
Blank inoculum*	9.12	9.18	9.26	9.18

*mean of 2 values

Biological degradation (closed bottle test)
	Concentration (mg/L)	% O2-consumption after days (d)
		7	14	21	28
Test substance	2	51	64	72	68
	5	39	58	63	66
Sodium benzoate	2	81	84	92	90

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The biodegradation of the test substance was determined in a closed bottle test according to OECD 301 D and GLP. Between 66 and 68% of the test substance was biodegraded within 28 days. No toxicty control was included. However, it could be observed that the substance had no inhibitory effects to the microorganisms up to a test concentration of 5 mg/L. The test substance was, therefore, classified as readily biodegradable according to OECD criteria.

Description of key information

Readily biodegradable: 66 - 68% within 28 days (O2 consumption, OECD 301 D)

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

The biodegradation of the test substance was determined in a closed bottle test according to OECD 301 D and GLP. Between 66 and 68% of the test substance was biodegraded within 28 days. No toxicty control was included. However, it could be observed that the substance had no inhibitory effects to the microorganisms up to a test concentration of 5 mg/L. The test substance was, therefore, classified as readily biodegradable according to OECD criteria.