Ethanone, 1-(3-methyl-2-benzofuranyl)-

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:

1997-11-07 to 1997-12-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Version / remarks:

1992

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Type: mixed population of aquatic microorganisms (activated sludge)
- Origin: effluent of laboratory scale unit receiving sewage from the Wupper area water authority (predominantly domestic sewage).

Duration of test (contact time):

28 d

Initial conc.:

3 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Test temperature: 20 +/- 1 °C
- pH adjusted: yes
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Glass bottle
- Number of culture flasks/concentration: 10 bottles

SAMPLING
- Sampling frequency: 7 day

CONTROL AND BLANK SYSTEM
- Inoculum blank: 10 bottles
- Process control: 10 bottles (Aniline)
- Toxicity control: 10 bottles (Aniline + test item)

Reference substance:

aniline

Key result

Parameter:

% degradation (O2 consumption)

Value:

4

Sampling time:

28 d

Results with reference substance:

80% degradation within 14 days

Dissolved oxygen of blank inoculum (mg O2/L after x day):

Bottle No.	0 days	Bottle No.	7 days	Bottle No.	14 days	Bottle No.	21 days	Bottle No.	28 days
1	8.83	3	8.56	5	8.55	7	8.55	9	8.54
2	8.83	4	8.62	6	8.63	8	8.59	10	8.62
Mean	8.83	Mean	8.59	Mean	8.59	Mean	8.57	Mean	8.58

Dissolved oxygen of reference substance (mg O2/L after x day):

Bottle No.	0 days	Bottle No.	7 days	Bottle No.	14 days	Bottle No.	21 days	Bottle No.	28 days
11	8.87	13	5.86	15	4.83	17	4.67	19	4.34
12	9.01	14	5.4	16	4.93	18	4.63	20	4.44
Mean	8.94	Mean	5.63	Mean	4.88	Mean	4.65	Mean	4.39

Dissolved oxygen of test substance (mg O2/L after x day):

Bottle No.	0 days	Bottle No.	7 days	Bottle No.	14 days	Bottle No.	21 days	Bottle No.	28 days
21	8.98	23	8.54	25	8.59	27	8.53	29	8.34
22	8.97	24	8.68	26	8.62	28	8.56	30	8.47
Mean	8.98	Mean	8.61	Mean	8.61	Mean	8.55	Mean	8.46

Dissolved oxygen of toxicity control (mg O2/L after x day):

Bottle No.	0 days	Bottle No.	7 days	Bottle No.	14 days	Bottle No.	21 days	Bottle No.	28 days
31	8.98	33	5.57	35	4.49	37	4.35	39	4.04
32	8.97	34	5.5	36	4.76	38	4.43	40	4.22
Mean	8.98	Mean	5.54	Mean	4.63	Mean	4.39	Mean	4.13

Results-Do depletion: % degradation

a. Testsubstance:

Test substance	DO depletion after n days
	7 d	14 d	21 d	28 d
No.1: (mt0-mtx)-(mb0-mbx)	0.2	0.15	0.19	0.29
No.2: (mt0-mtx)-(mb0-mbx)	0.06	0.12	0.16	0.26
D1: % Degradation	3	2	3	4
D2: % Degradation	1	2	2	4
D, Mean	2	2	3	4

b. Reference substance

Reference substance	DO depletion after n days
	7 d	14 d	21 d	28 d
No.1: (mt0-mtx)-(mb0-mbx)	2.77	3.8	3.94	4.28
No.2: (mt0-mtx)-(mb0-mbx)	3.37	3.84	4.12	4.32
D1: % Degradation	57	79	82	89
D2: % Degradation	70	80	86	90
D, Mean	64	80	84	90

c. Toxicitx control

Toxicity Control	DO depletion after n days
	7 d	14 d	21 d	28 d
No.1: (mt0-mtx)-(mb0-mbx)	3.17	4.25	4.37	4.69
No.2: (mt0-mtx)-(mb0-mbx)	3.23	3.97	4.28	4.5
D1: % Degradation	27	36	37	40
D2: % Degradation	28	34	37	38
D, Mean	28	35	37	39

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item was not readily biodegradable (4% based on O2 consumption) under the chosen test conditions.

Executive summary:

The ready biodegradability of the test item was tested according to council directive 92/69 EEC method C.4-E and GLP. The test item at a concentration of 3 mg was inoculated with 5 ml/L sewage effluent in closed glass bottles 28 d. The degradation process was followed by weekly measurements of the BOD in the aqueous phase. Degradation was expressed as BOD to ThOD in %. After 28 d, the average degradation rate of the test item was 4%, therefore, the test item was considered as not readily biodegradable. The degradation of the reference substance aniline reached 80% within 14 days, thus confirming the suitability of the inoculum.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The ready biodegradability of the test item was tested according to council directive 92/69 EEC method C.4-E and GLP. The test item at a concentration of 3 mg was inoculated with 5 ml/L sewage effluent in closed glass bottles 28 d. The degradation process was followed by weekly measurements of the BOD in the aqueous phase. Degradation was expressed as BOD to ThOD in %. After 28 d, the average degradation rate of the test item was 4%, therefore, the test item was considered as not readily biodegradable. The degradation of the reference substance aniline reached 80% within 14 days, thus confirming the suitability of the inoculum.