6-bromo-3-methyl-3H-dibenz[f,ij]isoquinoline-2,7-dione

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:

1988-12-01 - 1988-12-29 (experimental phase)

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

no GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

no

Remarks:

study conducted before 2008

Test material

Test material information

Constituent 1

Reference substance name:

6-bromo-3-methyl-3H-dibenz[f,ij]isoquinoline-2,7-dione

EC Number:

201-381-8

EC Name:

6-bromo-3-methyl-3H-dibenz[f,ij]isoquinoline-2,7-dione

Cas Number:

81-85-6

Molecular formula:

C17H10BrNO2

IUPAC Name:

6-bromo-3-methyl-3H-naphtho[1,2,3-de]quinoline-2,7-dione

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): secondary effluent of a domestic sewage treatment plant (Wupper area water authority, STP Odenthal)
- Pretreatment: separation of coarse particles by filtration; aeration of filtrate
- Concentration of sludge: 5 ml/L (effluent concentration in reaction mixture)

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

51.2 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

1.56 other: mg O2/mg

Based on:

COD

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

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

Reference substance

Reference substance:

aniline

Results and discussion

% Degradation

Key result

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

BOD5 / COD results

BOD5 / COD

Parameter:

COD

Value:

1.56 other: mg O2/mg

Results with reference substance:

88% degradation after 28 days has been determined with the reference substance aniline.
Theoretical Oxygen Demand (ThOD): 2409 mg/g

Any other information on results incl. tables

Degradation of test item

	5d	15d	28d
BOD (mg/L)	0.50	0.45	0.50
% degradation	1	1	1

Degradation of reference substance

Test concentration: 1.2 mg/L

	5d	15d	28d
BOD (mg/L)	1.95	2.35	2.55
%degradation	67	81	88

Oxygen measurement

Dissolved oxygen of mineral medium:

(mg O2/L after x days)

bottle-no.	0 days
1	9.3
2	9.3
mean	9.3

Dissolved oxygen of blank inoculum:

(mg O2/L after x days)

bottle-no.	0 days	bottle-no.	5 days	bottle-no.	15 days	bottle-no.	28 days
3	8.80	5	8.80	7	8.70	9	8.70
4	8.80	6	8.80	8	8.70	10	8.70
mean	8.80		8.80		8.70		8.70

Dissolved oxygen of test item:

(mg O2/L after x days)

bottle-no.	0 days	bottle-no.	5 days	bottle-no.	15 days	bottle-no.	28 days
11	8.90	13	8.80	15	8.70	17	8.70
12	8.80	14	8.80	16	8.80	18	8.70
mean	8.85		8.80		8.75		8.70

Dissolved oxygen of reference substance:

(mg O2/L after x days)

bottle-no.	0 days	bottle-no.	5 days	bottle-no.	15 days	bottle-no.	28 days
19	8.80	21	7.40	23	6.80	25	6.70
20	8.80	22	7.30	24	6.90	26	6.60
mean	8.80		7.35		6.85		6.65

Applicant's summary and conclusion

Validity criteria fulfilled:

not specified

Interpretation of results:

not readily biodegradable

Conclusions:

The study was conducted according to OECD 301 F on the registered substance itself. The method is to be considered scientifically reasonable and suitable for the test item with some deficiencies in documentation, but the available information allows the conclusion that the test was properly conducted. Hence, the results can be considered as reliable to assess ready biodegradability of the test item. A degradation of 1 % was determined, hence, the test item needs to be classified as not readily biodegradable.

Executive summary:

This report is based on a study report “Biodegradability of Pyridon, rein, trocken" (1988), the corresponding raw data and additional information from the executing laboratory “Institut für Umweltanalyse”, Dr. Kanne (Bayer AG Leverkusen – Germany). Recent regulatory requirements necessitate this re-evaluation.

The study was conducted in accordance EU method C.4-E. This test method is in all essential parts identical with OECD 301D.

A solution of the test item in a mineral medium was inoculated and incubated for 28 d under aerobic conditions. During this period, degradation was followed by BOD determinations. The reference compound aniline showed 81 % degradation after 15 days.

Result:

1 % degradation after 5 days

1 % degradation after 15 days

1 % degradation after 28 days

Therefore the test item is considered to be “not readily biodegradable“.