tetrasodium 2-(4-fluoro-6-(methyl-(2-(sulfatoethylsulfonyl)ethyl)amino)-1,3,5-triazin-2-ylamino)-5-hydroxy-6-(4-methyl-2-sulfonatophenylazo)naphthalene-1,7-disulfonate

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:

From June 22, 1999 to July 20, 1999

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-B (Determination of the "Ready" Biodegradability - Modified OECD Screening Test)

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Type: Mixed population of aquatic microorganisms (activated sludge)
Origin: Secondary effluent of a domestic sewage treatment plant (Kläranlage Odenthal)
Date of collection: June 26, 1999
Pretreatment: None
Treatment given: Separation of coarse particles by filtration

Duration of test (contact time):

28 d

Initial conc.:

19.1 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Remarks:

(the biodegradation of the test substance was determined on the basis of the reduction in DOC)

Details on study design:

- Concentration of the stock solution: 1 g/L
- Initial concentration of test substance: 19.1 mg/L DOC
- Initial concentration of reference substance: 19.8 mg/L DOC
- Concentration of effluents in reaction mixture: 0.5 mL/L
- Temperature: 22±2°C

TREATMENT
- Control (2 replicates)
- Test substance (2 replicates)
- Reference substance (2 replicates)
- Toxicity control (test and reference substance plus inoculum)

SAMPLING
- Samples were taken for analysis on 0, 7, 14, 21, 27 and 28 d
- The DOC content in each reaction vessel was determined twice at each time point

Reference substance:

benzoic acid, sodium salt

Remarks:

(99% pure)

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

28 d

Details on results:

Degradation of test substance:
12% degradation after 7 d
6% degradation after 14 d
1% degradation after 21 d
1% degradation after 27 d
0% degradation after 28 d

Results with reference substance:

Degradation of reference substance:
96% degradation after 7 d
97% degradation after 14 d
98% degradation after 21 d
98% degradation after 27 d
100% degradation after 28 d

- The used concentrations of the test substance did not show toxic effects to bacteria.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

Under the study conditions, the test substance was considered to be ‘not readily biodegradable’.

Executive summary:

A study was conducted to assess the ready biodegradability of the test substance according to EU Method C.4-B, in compliance with GLP.

Activated sludge was inoculated with 19.1 mg/L (expressed in terms of dissolved organic carbon (DOC)) of the test substance (in duplicate) and incubated under aerobic conditions at a constant temperature (22±2°C) for 28 d. Degradation was assessed by the determination of DOC on Days 0, 7, 14, 21, 27 and 28. A control solution, a reference test (containing the reference substance benzoic acid, sodium salt (19.8 mg/L DOC) together with inoculum) and a toxicity test (containing the test substance, reference substance and the inoculum) were used for validation purposes.

The test substance degraded 0% by Day 28. No toxicity was observed in the toxicity control. The reference substance showed 97% degradation at Day 14.Under the study conditions, the test substance was considered to be ‘not readily biodegradable’.

Description of key information

Under the study conditions, the test substance was considered to be ‘not readily biodegradable’.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

A study was conducted to assess the ready biodegradability of the test substance according to EU Method C.4-B, in compliance with GLP. Activated sludge was inoculated with19.1 mg/L (expressed in terms of dissolved organic carbon (DOC)) of the test substance (in duplicate) and incubated under aerobic conditions at a constant temperature (22±2°C) for 28 d. Degradation was assessed by the determination of DOC on Days 0, 7, 14, 21, 27 and 28. A control solution, a reference test (containing the reference substance benzoic acid, sodium salt (19.8 mg/L DOC) together with inoculum) and a toxicity test (containing the test substance, reference substance and the inoculum) were used for validation purposes.The test substance degraded 0% by Day 28. No toxicity was observed in the toxicity control. The reference substance showed 97% degradation at Day 14.Under the study conditions, the test substance was considered to be ‘not readily biodegradable’ (Müller, 2000).