Disodium 7-[(4-amino-3-methoxyphenyl)azo]naphthalene-1,3-disulphonate

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Remarks:

According to OECD 301B but limited documentation regarding the test material

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

Principles of method if other than guideline:

not applicable

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Disodium 7-[(4-amino-3-methoxyphenyl)azo]naphthalene-1,3-disulphonate

EC Number:

265-529-3

EC Name:

Disodium 7-[(4-amino-3-methoxyphenyl)azo]naphthalene-1,3-disulphonate

Cas Number:

65151-26-0

Molecular formula:

C17H15N3O7S2.2Na

IUPAC Name:

disodium 7-[(4-amino-3-methoxyphenyl)diazenyl]naphthalene-1,3-disulfonate

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: municipal biological sewage treatment plant, not adapted, not pre-conditioned; ARA Werdhoelzli, 8048 Zuerich, Switzerland
- Concentration of sludge: 0.2 g/L dry matter in the final mixture
- Preparation of inoculum for exposure: prior to the test the sludge was washed twice with tap water

Duration of test (contact time):

28 d

Initial test substance concentration

Initial conc.:

156 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

Test sample: the test material was diluted with mineral salts medium to give a final DOC concentration of about 50 mg/L

TEST CONDITIONS
- Composition of medium: as specified in OECD 302B
- Test temperature: 22 ± 2°C
- Aeration of dilution water: yes, with CO2-free air
- Concentration reference substance: 49.6 mg/L DOC/L

TEST SYSTEM
- Culturing apparatus: 1200 mL closed glass bottles containing a total volume of test solution of 600 mL
- Number of culture flasks/concentration: 2 replicates per test item concentration; 2 replicates per blank control, 1 replicate per positive control
- Measuring equipment: DOC was determined with Shimadzu 5050 TOC-Analyzer using the NPOC-mode; each analysis was carried out in duplicate
- Details of trap for CO2: 120 mL of 0.5 m sodium hydroxide solution respectively
- Sampling: samples were taken on days 1, 4, 7, 11,14, 18, 21, 25, 27 and 28

Reference substance

Reference substance:

diethylene glycol

Results and discussion

Preliminary study:

not applicable

Test performance:

not applicable

% Degradation

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

28 d

Details on results:

Based on the data of the individual DOC determinations no biodegradation of the test item was observed after 28 days of incubation.

BOD5 / COD results

Results with reference substance:

The positive control, diethyleneglycol, showed 99 % biodegradation after 14 days of incubation thus confirming suitability of inoculum and test conditions.
The test was considered valid, since the degradation of the reference compound reached more than 70 % within 14 days of incubation.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

No biodegradation of the test item was observed after 28 days.

Executive summary:

In the Zahn-Wellens test on the test substance according to OECD 302B, no biodegradation was observed after 28 days. The substance has to be regarded as not inherently biodegradable.

Diethyleneglycol attained 99 % degradation after 14 days thereby confirming the suitability of the inoculum and test conditions.