Reaction mass of 5,12-dihydroquino[2,3-b]acridine-7,14-dione and aluminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2-sulphonate) and dialuminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2,9-disulphonate)

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:

17 Nov 2016 to 15 Dec 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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 B (Ready Biodegradability: CO2 Evolution Test)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.3110 (Ready Biodegradability)

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: International Standard ISO 9439 (Water Quality - Evaluation in an aqueous medium of the "ultimate" aerobic biodegradability of organic compounds - Method by analysis of released carbon dioxide.)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 5,12-dihydroquino[2,3-b]acridine-7,14-dione and aluminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2-sulphonate) and dialuminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2,9-disulphonate)

EC Number:

909-092-5

Molecular formula:

Unspecified

IUPAC Name:

Reaction mass of 5,12-dihydroquino[2,3-b]acridine-7,14-dione and aluminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2-sulphonate) and dialuminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2,9-disulphonate)

Test material form:

solid

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
Storage at room temperature

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

Municipal activated sludge from the wastewater treatment plant of Mannheim, Germany. The inoculum was collected on 14 November 2016 from the aeration tank of the plant. A suitable aliquot of the activated sludge suspension was sieved by a finely woven mesh with a mesh size about 1 mm. To reduce the content of inorganic carbon in the blank controls the activated sludge was aerated with carbon dioxide free air for about 72 hours at 22 ± 2° C.

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

20 mg/L

Based on:

TOC

Initial test substance concentration 2

Initial conc.:

ca. 51 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
At the day of exposure the activated sludge suspension was washed one time with drinking water. Therefore the aeration was stopped and the sludge was allowed to settle. After settling the supernatant was discarded and the remaining sludge suspension was filled up with drinking water and the concentration oft the sludge was adjusted to 6.0 g/L dry weight. Aliquots of 7.5 mL were added to the test vessels to obtain an activated sludge concentration of 30 mg/L dry weight.

EXPERIMENTAL PROCEDURE
The following test assays were prepared:
- 2 blank control assays
- 2 test substance assays
- 1 inhibition control assay
- 1 reference substance assay

TEST SYSTEM
- Test vessels: The Carbon Dioxide Evolution Test was performed in 2 L incubation bottles filled up to a volume of 1.5 L. The bottles were connected to two serial scrubbing bottles (total volume 250 mL) filled with 100 mL 0.05 mol sodium hydroxide solution for the adsorption of carbon dioxide from biodegradation processes. Usually twice a week the Total Inorganic Carbon (TIC) values of the adsorption solutions of the first trap were determined and used for the calculation of the produced carbon dioxide. After each sampling the second trap was moved forward and the new trap with fresh sodium hydroxide solution was placed into the second position. Each trap was analysed separately.
- Preparation: The TIC-value of the freshly prepared sodium hydroxide solution was determined and considered by the calculation of biogenic produced carbon dioxide amount. The incubation bottles were stirred on magnetic stirrers; the aeration was performed with carbon dioxide free air at a flow of approximately 800 mL per hour. The test assays were prepared at the day of exposure. First, the required volumes of deionised water and the solutions of mineral salts were dosed to all test vessels.
- Addition of test substance: For preparation of the test vessels with test substance, the required amounts of the test substance aliquots for a test concentration of 20 mg/L TOC were weighed onto small plastic cups and completely added with the plastic cups to the vessels of the test substance assays and to the vessel of the inhibition control. Because of poor water solubility of test substance these test assays were treated for few minutes in an ultrasonic bath to ensure an even distribution of test substance in test medium. Finally enough reference substance stock solution was added to reach 20 mg TOC/L in the reference substance assay and 20 mg TOC/L in the inhibition control, related to aniline.
- pH adjustmed: The pH-values in the test vessels were measured and adjusted to 7.4 ± 0.2, if necessary.
- Suspendid solids concentration: Aliquots of activated sludge suspension were added to all test vessels, to adjust the concentration of activated sludge to 30 mg/L dry weight.

SAMPLING
Samples for DIC-measurement (validity criterion) from the blank control assays were taken. For determination of the decrease of dissolved organic carbon (DOC) samples were taken from the test vessels of the blank control and from the test vessel of the reference substance control and the DOC content was determined after centrifugation (approx. 15 minutes at 4000 rpm). At begin of the exposure phase the test vessels were connected with an aeration unit and the bubble aeration with carbon dioxide free air was started after connecting the several test vessels with the absorption units. The test assays were stirred using magnetic stirrers. At the end of exposure, the pH values were measured in each test vessel. For stripping of carbon dioxide, dissolved in the test medium, each test vessel was acidified by adding 2 mL of concentrated hydrochloric acid. The concentration of dissolved organic carbon in the blank controls and reference substance assays were determined. Since the test substance was insufficiently soluble in water, no DOC-measurements could be performed from the test assay of the inhibition control and from the test substance test assays. The aeration was continued for about 24 hours and the released carbon dioxide amounts in both traps of each test vessel were determined and added to the calculated amount of the previous day.

Reference substance

Reference substance:

aniline

Results and discussion

Test performance:

VALIDITY CRITERIA
- Measured DIC-concentrations in the blank controls at begin of exposure (mean value): 0.6 mg/L
- Amount of produced CO2 in the blank controls at the end of exposure (mean value): 38.9 mg/L
- Deviation of the degree of biodegradation of the test substance in the plateau phase was <20%
- The degree of biodegradation of the reference substancewas >60% CO2/ThCO2 after 14 days (see 'Results with reference substance')
- The degree of biodegradation in the inhibition control was >25 % CO2/ThCO2 after 14 days
- The content of DIC in the blank control at start of exposure at the test concentration of 20 mg/L TOCwas <1 mg/L
- The amount of produced CO2 in the inoculum blank (“blank controls”) at the end of exposure (mean value) was <70 mg/L

% Degradation

Parameter:

% degradation (CO2 evolution)

Value:

< 10

Sampling time:

28 d

Details on results:

The test substance was biodegraded up to 9% after 28 days. A summary of the results is tabulated in 'Any other information on results incl. tables'. The degree of biodegradation in the inhibition control after 14 days was 29%.

BOD5 / COD results

Results with reference substance:

Degree of biodegradation of the reference substance after 14 days: 66% CO2/ThCO2. See 'Any other information on results incl. tables'.

Any other information on results incl. tables

Table: Degree of biodegradabion; [% CO2/ ThCO2]

Test duration [days]	RS	IH	TS1	TS2	TS mean value
0	0	0	0	0	0
1	1	0	1	0	1
4	24	7	3	0	2
7	44	19	4	0	2
11	55	25	7	0	4
14	66	29	8	2	5
18	77	34	9	1	5
21	83	37	12	2	7
25	89	41	15	2	9
27	92	43	15	2	9
28	94	44	17	1	9

RS: reference substance assay

IH: inhibition control assay

TS: test substance assay

Table: Theoretical Carbon dioxide [mg/test assay]

RS : 109.6

IH : 219.0

TS1 : 110.6

TS2 : 110.3

Table: Produced carbon dioxide amount in the test vessels

[mg CO2/test vessel]						mg CO2 added up after subtra of the mean value of the blank controls.
Duration of exposure [days]	BC mv	RS	IH	TS1	TS2	RS	IH	TS1	TS2
1	1.2	2.1	1.9	2.2	1.5	0.9	0.7	1.0	0.3
4	5.7	30.6	21.3	7.8	5.7	25.8	16.3	3.1	0.3
7	7.2	29.6	32.7	9.0	7.3	48.2	41.8	4.9	0.4
11	8.8	20.6	20.8	11.2	8.8	60.0	53.8	7.3	0.4
14	6.0	18.4	16.5	7.6	7.8	72.4	64.3	8.9	2.2
18	7.2	19.4	16.6	8.7	6.5	84.6	73.7	10.4	1.5
21	5.0	11.3	13.0	7.6	5.2	90.9	81.7	13.0	1.7
25	5.6	12.3	14.5	8.8	5.9	97.6	90.6	16.2	2.0
27	3.6	7.3	6.8	4.4	3.9	101.3	93.8	17.0	2.3
28	2.4	4.1	3.5	2.6	2.2	103.3	95.5	18.6	1.2
29	5.7	6.0	6.3	7.1	4.8

BCmv: blank control mean value

RS: reference substance assay

IH: inhibition control assay

TS: test substance assay

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

See 'Test performance'.

Interpretation of results:

not readily biodegradable

Conclusions:

The test substance is not readily biodegradable according OECD criteria. It is poorly biodegradable.