Reaction mass of 6-(2-ethyl-6-methylanilino)-5-(4-{4-[ethyl(3-sulfobenzyl) amino] phenylazo} phenylazo)-4-hydroxynaphthalene-2-sulfonic acid, sodium and/or disodium salt(s) and 6-(2-ethyl-6-methylanilino)-5-(4-{4-[ethyl(4-sulfobenzyl) amino] phenylazo} phenylazo)-4-hydroxynaphthalene-2-sulfonic acid, sodium and/or disodium salt(s)

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)

Version / remarks:

1992

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Acid Navy RN-2682

IUPAC Name:

Acid Navy RN-2682

Test material form:

solid

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Duration of test (contact time):

35 d

Initial test substance concentration

Initial conc.:

70.3 - 70.4 mg/L

Based on:

DOC

Details on study design:

Light conditions: test flasks were incubated in a dark room.

Reference substance

Reference substance:

benzoic acid, sodium salt

Results and discussion

% Degradation

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

28 d

Details on results:

In test flasks, containing test item and activated sludge (inoculum), fluctuating DOC concentrations were measured during the exposure period of 35 days. On exposure Day 35, the measured DOC concentrations were not significantly different from the initial mean DOC concentrations measured on Day 0. The fluctuating DOC concentrations are most likely due to adsorption and desorption of the test item on the activated sludge (inoculum).
This assumption is supported by the DOC concentrations of the test item measured on Day 0, which were below the aspired theoretical values.
Therefore, test item is classified as not biodegradable under the test conditions.
In the toxicity control, containing the test item, the reference item sodium benzoate and activated sludge (inoculum), the initial DOC decreased by 51 % within 14 days of exposure. Thus, according to the test guidelines the test item was not inhibitory to activated sludge at the tested concentration of 70 mg/l because degradation was >35 % within 14 days.

Points of degradation plot (test substance):
0 % degradation after 3 d
0 % degradation after 7 d
16 % degradation after 14 d
0 % degradation after 28 d

BOD5 / COD results

Results with reference substance:

The reference item sodium benzoate was completely (>90%) biodegraded within seven days of exposure, thus confirming suitability of the activated sludge.

Points of degradation plot:
100 % degradation after 3 d
100 % degradation after 7 d
100 % degradation after 14 d
99 % degradation after 28 d

Applicant's summary and conclusion

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

Not biodegradable under test conditions.