Reaction mass of 1,5-Naphthalenedisulfonic acid, 3,3'-[(4-methyl-1,2-phenylene)bis[imino(6-chloro-1,3,5-triazine-4,2-diyl)imino[2-(acetylamino)-5-methoxy-4,1-phenylene]-2,1-diazenediyl]]bis-, sodium salt (1:4) and 1,5-Naphthalenedisulfonic acid, 3,3'-[(3-methyl-1,2-phenylene)bis[imino(6-chloro-1,3,5-triazine-4,2-diyl)imino[2-(acetylamino)-5-methoxy-4,1-phenylene]-2,1-diazenediyl]]bis-, sodium salt (1:4)

Biodegradation in water: screening tests

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Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From November 25, 1988 to April 24, 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: EEC directive 84/449/EEC

Deviations:

no

Test guideline 2

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method C.5 (Degradation: Biochemical Oxygen Demand)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Test material form:

solid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Duration of test (contact time):

5 d

Initial test substance concentration

Initial conc.:

1.11 g/L

Based on:

test mat.

Details on study design:

5-day Biochemical Oxygen Demand (BOD5): This was carried out at 25 times dilution and a 250 times dilution of the standard solution of the test substance. The procedure used was the internal protocol (Brixham laboratory version (SOP BI23))). In outline this procedure involved incubating the sample in a completely full and stoppered bottle using a dilution medium consisting of deionised water containing prescribed inorganic salts and a bacterial inoculum
Prepared from a treated domestic sewage effluent. The incubation was carried out at a nominal 20˚C and BOD5 calculated at the end of 5 day by measuring the dissolved oxygen in bottles in comparison with controls.

Chemical oxygen demand (COD): The procedure involves refluxing an aliquot of the test substance standard solution with excess of acidified potassium dichromated in the presence of silver sulphate and mercury sulphate. After cooling the excess dichromate was titrated with ferrous ammonium sulphate using a ferrous phenanthroline indicator.

Results and discussion

% Degradation

Key result

Parameter:

other: BOD5/COD

Remarks:

% degradation

Value:

8.85

Sampling time:

5 d

Remarks on result:

other: Not readily biodegradable

BOD5 / COD results

BOD5 / COD

BOD5 / COD 1

Key result

Parameter:

BOD5

Value:

< 0.1 g O2/g test mat.

BOD5 / COD 2

Key result

Parameter:

COD

Value:

1.13 g O2/g test mat.

Any other information on results incl. tables

Results:

BOD5: The results at the 25 times dilution showed a mean difference of 0.53 mg/L between the test sample and controls, and at the 250 times dilution a mean difference of 1.33 mg/L. These differences corresponded to BOD5 of the test substance of 0.01 g O2/g and O.30 g O2/g respectively. It is considered unlikely that a dyestuff with the structure of the test substance would give BOD5 and the result at 25 times dilution is therefore considered more reliable and the BOD5 of the test substance recorded as < 0.1 g O2/g of substance.

COD: The result shows that the test substance standard solution had a COD strength of 1124 O2/L corresponding to COD of 1.01 g O2/g or1.13 g O2/g test substance.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Under the experimental conditions, biodegradation of the test substance was equivalent to 8.85%. The substance was therefore not considered to be readily biodegradable.

Executive summary:

A study was conducted to determine the biodegradability of the test substance based on BOD and COD in a 5 d study. The test involved measuring reduction in dissolved oxygen in the presence of the test substance. Biological inoculum was obtained from a river, downstream of a treatment plant handling mainly domestic sewage. A bottle was set up containing dilution water seeded with the bacteria (blank). An aliquot of the test substance stock solution was added to the dilution water to give the required concentration for the study. The dissolved oxygen concentration was measured in all bottles at test start (Day 0) and after 5 d. Oxygen consumption was calculated by comparing dissolved oxygen (DO) loss in the test substance samples versus controls. The BOD of the sample was calculated in g O2 consumed per g of test substance and degradation was reported as a percentage of sample COD. The COD involves oxidation of the test substance under standard conditions by acidified dichromate and titration of the residual dichromate with ferrous ammonium sulphate solution. Under the experimental conditions, biodegradation of the test substance was equivalent to 8.85%. The substance was therefore not considered to be readily biodegradable (Brown, 1989).