14H-benz[4,5]isoquino[2,1-a]perimidin-14-one

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2014-08-22 till 2014-12-05

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guideline study without restrictions.

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

(2008)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

(adopted July 1992)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Test organisms
Type : mixed population of aquatic microorganisms (activated sludge)
Origin : aeration tank of a wastewater plant treating predominantly domestic sewage (Wupper area water authority, WWTP Odenthal)
Date of collection : 2014-08-25
Concentration of inoculum : 30 mg/L suspended solids

Pre-treatment of the inoculum
− Before use, the inoculum was stored for one day at room temperature under continuous shaking with aeration.
− The sludge was washed twice by adding mineral medium and centrifuging for 10 min at 2000 rpm and 20 °C and decanting off the supernatant.
− An aliquot of the wet sludge was dried in order to determine the wet weight / dry weight ratio of the sludge and to prepare a stock suspension (activated sludge) of 3 g dw/L.
− The calculated amount of sludge, needed to achieve 300 mL of this stock suspension, was dissolved in mineral medium and then filled up to a defined end volume.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

A suspension of 100 mg/L 14H-benz[4,5]isoquino[2,1-a]perimidin-14-on in a mineral medium, equalling to 50-100 mg ThOD or COD/Litre as the nominal sole source of organic carbon, was stirred in a closed flask and inoculated at a constant temperature (22 ± 1 °C) for up to 28 days under aerobic conditions in the dark.
The consumption of oxygen (BOD) was determined by measuring the drop in pressure in the automated respirometer flasks. Evolved carbon dioxide was absorbed in sodium hydroxide. The amount of oxygen taken up by the test item (corrected for uptake by blank inoculum, run in parallel) was expressed as a percentage of theoretical oxygen demand (ThOD).
The endogenous activity of the inoculum was checked running parallel blanks with inoculum but without test item. A reference compound (sodium benzoate) was run in parallel to check the operation of the procedures.
A toxicity control (14H-benz[4,5]isoquino[2,1-a]perimidin-14-one and reference compound mixed, one replicate) was run in parallel, to ensure that the chosen concentration of the test item was not inhibitory to microorganisms.
Degradation was followed by the determination of oxygen uptake and measurements were taken at frequent intervals to allow the identification of the beginning and end of biodegradation and the slope of the biodegradation curve.
Because of the nature of biodegradation and of the mixed bacterial populations used as inoculum, determinations of test item and inoculum blank were carried out in triplicate and of reference compound in duplicate.
The oxygen uptake was calculated from the readings taken at regular and frequent intervals, using the method given by the manufacturer of the equipment. At the end of incubation, the pH was measured in the flasks.
14H-benz[4,5]isoquino[2,1-a]perimidin-14-one is an N-containing substance. Therefore, the concentration of nitrite and nitrate was determined at the start of the test. The oxygen consumed by nitrification was not determined after 28 days, because no degradation of the test item was observed.

Exposure conditions
- Test volume : 250 mL
- Test apparatus : OxiTopControl System (WTW)
- Mixing : 1 magnetic stirrer per test vessel
- Incubation time : 28 days
- Incubation temperature : 22 ± 1 °C

Reference substance:

benzoic acid, sodium salt

Remarks:

(Sigma-Aldrich, batch no.: 1438955, purity: 99.7 %, 100 mg/L)

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

21 d

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

The used concentrations of 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one did not show toxic effects to bacteria.

Parameter:

COD

Value:

2.297 other: mg O2/mg

Results with reference substance:

Kinetic of reference substance (% Degradation)
78 after 7 days
88 after 14 days
91 after 21 days
91 after 28 days

After 28 days the pH values of different flasks are in the range of 7.4 -8.0.

Validity criteria fulfilled:

yes

Remarks:

(- Ready biodegradation of reference compound ≥ 60 % within 14 days. - In the toxicity control degradation rates > 25 % within 14 days. - Replicates difference < 20 %. - Oxygen uptake of blank inoculum was ≤ 60 mg/L.)

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Within 28 days, a degradation rate of 0 % was determined. 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one is considered to be "Not Readily Biodegradable". The reference compound sodium benzoate showed 88 % degradation after 14 days.

Executive summary:

To test for its biodegradability potential, 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one was incubated for 28 days in continuously stirred 250 mL closed flask (in duplicate) in the dark with an inoculum originally collected from a local, predominantly municipal wastewater treatment plant. In this assay, biodegradation was estimated by biological oxygen demand (BOD) over time. BOD was measured daily by a manometer. The incubatioon temperature was 22 °C, pH was 7.4 - 8.0. The concentration of inoculum was 30 mg/L and the one of 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one was 100 mg/L. Degradation was calculated by substracting the amount BOD in the negative (inoculum only) control from that in 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one or positive control at any given time point and divided by the chemical oxygen demand (COD) or thereotical oxygen demand (ThOD). The 28 -day degradation was 0 % and for the positive control (with reference substance) the biodegradation was 91 %.

In conclusion 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one is not readily biodegradable.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-06-26 till 2015-09-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD guideline study without restrictions.

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1192

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

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

Version / remarks:

2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

Test organisms
Type : mixed population of aquatic microorganisms (activated sludge)
Origin : aeration tank of a wastewater plant treating predominantly domestic sewage (Wupper area water authority, WWTP Odenthal)
Date of collection : 2015-06-29
Concentration of inoculum : 30 mg/L suspended solids
Pre-treatment of the inoculum: separation of coarse particles by filtration, aeration of the resulting inoculum for 1 day
Effluent concentration of reaction mixture: 5 mL/L (5.8 mL/1.16 L)

Duration of test (contact time):

28 d

Initial conc.:

0.5 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

The method assessed the ready biodegradability of 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one under aerobic conditions at 22 ± 2°C in the dark. The test lasted for 28 days. During this period, the biodegradation was determined on the basis of the reduction of dissolved oxygen (BOD). A measured volume of inoculated mineral medium, containing a known concentration of 0.5 mg 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one/L (usually 2-10 mg/Litre), to give usually 5-10 mg ThOD/Litre as the nominal sole source of organic carbon in a closed flask was applied. The degree of biodegradation was calculated by the amount of oxygen taken up by the test item (corrected for that in the blank inoculum control) as a percentage of COD (chemical oxygen demand).

The following flasks were used:
− Test suspension (30 flasks)
A measured volume of mineral medium containing a known concentration of 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one (as the nominal sole source of organic carbon) and inoculum.
− Reference control (10 flasks)
In order to check the procedure, the reference compound sodium benzoate was tested in parallel to the normal test runs.
− Inoculum blank (10 flasks)
A measured volume of mineral medium containing only inoculum.

Because of the nature of biodegradation and of the mixed bacterial populations used as inoculum, all determinations were carried out in duplicate.

Exposure conditions
- Test volume : 1.16 L
- Incubation time : 28 days
- Incubation temperature : 22 ± 1 °C

Reference substance:

benzoic acid, sodium salt

Remarks:

(Acros Organics, batch no.: A0357641, purity: 99.9 %, 2.9 mg/L)

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

7

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

21 d

Parameter:

% degradation (O2 consumption)

Value:

5

Sampling time:

28 d

Details on results:

A toxicity control (14H-benz[4,5]isoquino[2,1-a]perimidin-14-one and reference compound mixed) was not run in parallel, because the chosen concentration of the test item was not inhibitory to microorganisms (see study 2013/0070/08, Neuhahn, 2014).

Parameter:

COD

Value:

2.297 other: mg O2/mg

Results with reference substance:

Kinetic of reference substance (% Degradation)
76 after 7 days
79 after 14 days
86 after 21 days
85 after 28 days

After 28 days the pH values of different flasks are in the range of 6.8 -7.0.

Validity criteria fulfilled:

yes

Remarks:

(- Ready biodegradation of reference compound ≥ 60 % within 14 days. - Oxygen uptake of blank inoculum was ≤ 60 mg/L.)

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Within 28 days, a degradation rate of 5 % was determined. 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one is considered to be "Not Readily Biodegradable". The reference compound sodium benzoate showed 79 % degradation after 14 days.

Executive summary:

This study was designed to assess the ready biodegradability of 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one.

It was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.4-E “Closed Bottle Test (2008)”. This test method is in all essential parts identical with OECD Guideline 301 D (adopted July 1992).

The method assessed the ready biodegradability of 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one under aerobic conditions at 22 ± 2 °C in the dark.

The test lasted for 28 days. During this period, the biodegradation was determined on the basis of the reduction of dissolved oxygen (BOD). A measured volume of inoculated mineral medium, containing a known concentration of 0.5 mg 14H-benz[4,5]isoquino[2,1 -a]perimidin-14 -one/L (usually 2 -10 mg/L), to give usually 5 -10 mg ThOD/L as the nominal sole source of organic carbon in a closed flask was applied.The degree of biodegradation was calculated by the amount of oxygen taken up by 14H-benz[4,5]isoquino[2,1 -a]perimidin-14 -one (corrected for that in the blank inoculum control) as a percentage of COD (chemical oxygen demand).

The pH was in the range of 6.8 - 7.0 after 28 days.

The 28 -day degradation was 5 % and for the reference substance the biodegradation was 79 %.

In conclusion 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one is not readily biodegradable.

Description of key information

Neuhahn, 2014:
Within 28 days, a degradation rate of 0 % was determined. 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one is considered to be "Not Readily Biodegradable". The reference compound sodium benzoate showed 88 % degradation after 14 days.
Spoo-Klöppel:
Within 28 days, a degradation rate of 5 % was determined. 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one is considered to be "Not Readily Biodegradable". The reference compound sodium benzoate showed 79 % degradation after 14 days.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Spoo-Klöppel, 2015 reported:

This study was designed to assess the ready biodegradability of 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one.

It was conducted in accordance with the Council Regulation (EC) No 440/2008, Method C.4-E “Closed Bottle Test (2008)”. This test method is in all essential parts identical with OECD Guideline 301 D (adopted July 1992).

The method assessed the ready biodegradability of 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one under aerobic conditions at 22 ± 2 °C in the dark.

The test lasted for 28 days. During this period, the biodegradation was determined on the basis of the reduction of dissolved oxygen (BOD). A measured volume of inoculated mineral medium, containing a known concentration of 0.5 mg 14H-benz[4,5]isoquino[2,1 -a]perimidin-14 -one/L (usually 2 -10 mg/L, to give usually 5 -10 mg ThOD/L as the nominal sole source of organic carbon in a closed flask was applied. The degree of biodegradation was calculated by the amount of oxygen taken up by 14H-benz[4,5]isoquino[2,1 -a]perimidin-14 -one (corrected for that in the blank inoculum control) as a percentage of COD (chemical oxygen demand).

The pH was in the range of 6.8 - 7.0 after 28 days.

The 28 -day degradation was 5 % and for the reference substance the biodegradation was 79 %.

In conclusion 14H-benz[4,5]isoquino[2,1-a]perimidin-14-one is not readily biodegradable.