Hexasodium 4,4'-[1,4-phenylenebis[imino(6-chloro-1,3,5-triazine-4,2-diyl)imino]]bis[5-hydroxy-6-[(2-sulphonatophenyl)azo]naphthalene-2,7-disulphonate]

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20 September 1995 to 18 October 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: study according to the guideline under GLP

Qualifier:

according to guideline

Guideline:

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

Deviations:

yes

Remarks:

single samples per test vessel were analysed for DOC

GLP compliance:

yes

Oxygen conditions:

anaerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum: Activated sludge of a communal sewage treatment plant Ara Reinach collected on 19.09.95
- Storage conditions: no data
- Storage length: one day
- Preparation of inoculum for exposure: no data
- Pretreatment: none reported
- Concentration of sludge: 530 mg/L

Duration of test (contact time):

28 d

Initial conc.:

593 mg/L

Based on:

test mat.

Initial conc.:

150 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: accoding to the guideline
- Additional substrate: none
- Solubilising agent : none
- Test temperature: 21.1-22.8 °C
- pH: 6.8-7.5
- pH adjusted: no data
- Aeration of dilution water: yes (O2 concentration 6.2-8.3 mg/L)
- Continuous darkness: no, indirect daylight

TEST SYSTEM
- Culturing apparatus: 2 L vessel containing test substance, activated sludge and mineral medium (agitated)
- Number of culture flasks/concentration: 2 for test substance, one for abiotic control, one for reference substance
- Method used to create aerobic conditions: no data
- Measuring equipment: TOC/DOC Analyzer 500

SAMPLING
- Sampling frequency: at start, after 3 hours and on day 1, 2, 5, 7, 9, 12, 14, 16, 19, 21, 23, 27 and 28
- Sampling method: no data
- Sample storage before analysis: no data


CONTROL AND BLANK SYSTEM
- Inoculum blank: included
- Toxicity control: included

STATISTICAL METHODS: N/A

Reference substance:

diethylene glycol

Preliminary study:

Absorption (corrected for blank): 0%

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

28 d

Details on results:

results are average of 2 tests running in parallel

Results with reference substance:

The biodegradation, corrected by the blank control and measured as DOC (mg/l) is: 98 % on 8th day (average of 2 tests running in parallel).

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

The substance is not inherently biodegradable

Executive summary:

In a Zahn-Wellens test the substance did not show any biodegradation over a 28 day period. Therefore it is concluded that the substance is not inherently biodegradable.

Description of key information

In a Zahn-Wellens test the substance did not show any biodegradation over a 28 day period. Therefore it is concluded that the substance is not inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater