Disodium 6-(4,6-dichloro-1,3,5-triazin-2-ylamino)-1-hydroxy-2-(4-(2-(sulfonatooxy)ethylsulfonyl)phenylazo)naphthalene-3-sulfonate

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:

1999-03-24 to 1999-04-21

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)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

other: mixed population of aquatic microrganisms (activated sludge)

Details on inoculum:

Inoculum
source of sewage effluent: secondary effluent of a domestic sewage treatment plant (Kläranlage Odenthal);
Treatment given: separation of coarse particles by filtration
Concentration of effluents in reaction mixture: 5 mL/L (SOP 2030-6600103-99 D)
Preconditioning: aeration 5 days

Duration of test (contact time):

28 d

Initial conc.:

8 mg/L

Based on:

test mat.

Initial conc.:

2.9 mg/L

Based on:

other: Reference Substance: Sodium bensoate, 99% Purity

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

During the study period the biodegradation of the test substance is determined on the basis of the reduction of dissolved oxygen.

Details on study design:

TEST CONDITIONS

- Solubilising agent (type and concentration if used): no data
- Test temperature: 20 ± 1°C
- pH adjusted: yes
- other: Improved type for a volatile substance used (no further details given)
CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes (Sodium benzoate)

TEST SYSTEM

- Measuring equipment: According to SOP 2030-0000104-98 D
- Test performed in closed vessels

INOCULUM:
Source of sewage effluent: secondary effluent of a domestic sewage treatment plant (Kläranlage Odenthal)
Treatment given: Separation of coarse particles by filtration
Concentration of effluents in reaction mixture: 5 mL/L
-Preconditioning: aeration for 5 days.
Study condition:
Duration: 28 days


SAMPLING (- Sampling frequency - Sampling method- Sample storage before analysis : according to the guideline) as well as SOP 2030-6600401-96 D

REFERENCE SUBSTANCE: sodium benzoate
PURITY: 99%
Initial concentration: 2.9 mg/L reference substance

Reference substance:

other: Natriumbenzoat

Test performance:

Test substance is suspended in a mineral medium, inoculated with a mixed population of aquatic microorganisms and incubated for 28 days under aerobic conditions in the dark at 20 ± 1°C

Parameter:

other: Dissolved oxygen depletion

Value:

0

Sampling time:

28 d

Details on results:

Points of degradation plot (test substance): 1 % degradation after 7 d 0 % degradation after 14 d 1 % degradation after 21 d 0 % degradation after 28 d
The test results indicate no hazard potential.

Results with reference substance:

Points of degradation plot (reference substance): 70 % degradation after 7 d 78 % degradation after 14 d 85 % degradation after 21 d 84 % degradation after 28 d
see more details below.

Results-DO depletion: % Degradation

 

Test substance Test concentration: 8.4 mg/L ThoD: 839 mg/g COD---mg/g	DO depletion after n days                                 [mg/L]
No.1: (mt0-mtx)-(mb0-mbx)	7 d 0.04	0.00	0.07	0.00
No.2: (mt0-mtx)-(mb0-mbx)	0.00	0.00	0.07	0.00
D1: % Degradation	1	0	1	0
D2: % Degradation	0	0	1	0
D, Mean	0	0	1	0

 

Reference substance Test concentration: 2.9 mg/L ThoD: 1665 mg/g COD---mg/g	DO depletion after n days                                              [mg/L]
No.1: (mt0-mtx)-(mb0-mbx)	7d 3.35	14d 3.74	21d 4.08	28d 4.03
No.2: (mt0-mtx)-(mb0-mbx)	3.40	3.76	4,13	4.06
D1: % Degradation	69	77	84	83
D2: % Degradation	70	78	86	84
D, Mean	70	78	85	84

 

*Toxicity control	DO depletion after n days                                              [mg/L]
No.1: (mt0-mtx)-(mb0-mbx)	7d 3.29	14d 3.70	21d 4.08	28d 4.03
No.2: (mt0-mtx)-(mb0-mbx)	3.34	3.82	4.13	4.10
D1: % Degradation	28	31	34	34
D2: % Degradation	28	32	35	35
D, Mean	28	32	35	35

 

*In the toxicity control 8.4 mg/L test substance and 2.9 mg/L reference substance were used. The ThOD values respectively COD values of these substances are shown in the table above.

 

Dissolved oxygen(mg O2/l, mean values)

No. of days	Blank inoculum (bottles 1-10)	Refernce substance (bottles 11-20)	Test substance (bottles 41-50)	Toxicity Control (bottles 51-60)
0	9.42	9.41	9.36	9.35
7	9.15	5.76	9.08	5.76
14	8.96	5.2	8.94	5.13
21	8.98	4.86	8.85	4.8
28	8.71	4.65	8.8	4.57

 

Oxygen depletionafter 28 d (mg/l, mean values):

Inoculum blank	No data
Test substance	0
Reference substance	84
Toxicity control	35

Result: Within the test period of 28 days, a degradation of 0 % was determinded for Reaktiv-Orange DYPR 934. Reaktiv-Orange DYPR 934 has to be classified as “Not Readily Biodegradable”

Biodegradability:

0 % (28 d)

Method: Modified OECD Screening Test

The test results indicate no hazard potential.

The test substance is not readily biodegradable; so longer resident times of the substance in surface water are to be expected. However on the basis of the ecotoxicological test results there is no hazard potential.

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test substance is not readily biodegradable.

Executive summary:

 

Result: Within the test period of 28 days, a degradation of 0 % was determinded for Reaktiv-Orange DYPR 934. Reaktiv-Orange DYPR 934 has to be classified as “Not Readily Biodegradable”

Biodegradability = 0 %

Description of key information

A structural analogue of the Substance showed within the test period of 28 days, a degradation of 0 %. Hence, the Substance has to be classified as “Not Readily Biodegradable”

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

A study was performed with a structural analogue (SA01) to assess the ready biodegradability of test substance. The test substance in a mineral medium was inoculated with secondary effluent and incubated for 28 d under aerobic conditions. During this period the biodegradation of the test substance was determined. The test substance (structurally similar substance) showed 0 % degradation after 28 d. Therefore, the test substance is classified as 'not readily biodegradable'.