1,7-Naphthalenedisulfonic acid, 2-[[4-chloro-6-(cyanoamino)-1,3,5-triazin-2-yl]amino]-5-hydroxy-6-[2-[2-methoxy-5-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]diazenyl]-, lithium sodium salt (1:?:?)

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 Jul. 08, 1999 to Sep. 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

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)

Deviations:

no

Principles of method if other than guideline:

No

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): Secondary effluent of a domestic sewage treatment plant (KIaranlage Odenthal)
- Preparation of inoculum for exposure: Separation of coarse particles by filtration
- Concentration of effluent in reaction mixture: 0.5 mL/L

Duration of test (contact time):

28 d

Initial conc.:

18.3 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral medium
- Test temperature: 22 ± 2 °C

TEST SYSTEM
- Culturing apparatus: Flasks
- Number of culture flasks/concentration: 7 Flasks
- Test performed in closed vessels due to significant volatility of test substance: Yes
- Test performed in open system: No


SAMPLING
- Sampling frequency: 0, 7, 14, 21, 27 and 28 d
- Sampling method: Degradation is followed by determination of DOC over a 28 d period.


CONTROL AND BLANK SYSTEM
- Inoculum blank: A measured volume of mineral medium containing only inoculum
- Procedure control: The reference chemical sodium benzoate is tested by setting up 2 flasks in parallel to the normal tests runs
- Toxicity control: containing test substance, reference substance and inoculum

Reference substance:

benzoic acid, sodium salt

Remarks:

19 mg/L DOC

Preliminary study:

No data

Test performance:

No data

Parameter:

% degradation (DOC removal)

Value:

16

Sampling time:

28 d

Parameter:

% degradation (DOC removal)

Value:

4

Sampling time:

14 d

Details on results:

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

Results with reference substance:

The reference substance showed 99 % degradation within 14 d

Toxicity control: Showed 56 % of 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:

under test conditions no biodegradation observed

Conclusions:

Under the test conditions, the test substance is classified as not readily biodegradable.

Executive summary:

A study was performed to assess the ready biodegradability of test substance according to EU Method C.4-B. and OECD Guideline 301 E in compliance with GLP.

 

The test substance in a mineral medium was inoculated with secondary effluent and incubated for 28 d under aerobic conditions. During this period the biodegradation of the test substance was determined on the basis of reduction in DOC.

The test substance showed 16 % degradation after 28 d. Therefore, the test substance is classified as not readily biodegradable. The reference substance showed 99 % degradation within 14 d.

 

Under the test conditions, the test substance is classified as not readily biodegradable.

Description of key information

Degradation of 16 % was determined for test substance within the test period of 28 d. Hence, test substance is classified as 'Not Readily Biodegradable'.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

A study was performed to assess the ready biodegradability of test substance according to EU Method C.4-B. and OECD Guideline 301 E.

 

The test substance in a mineral medium was inoculated with secondary effluent and incubated for 28 d under aerobic conditions. During this period the biodegradation of the test substance was determined on the basis of reduction in DOC.

The test substance showed 16 % degradation after 28 d. Therefore, the test substance is classified as not readily biodegradable. The reference substance showed 99 % degradation within 14 d.

 

The test substance is classified as not readily biodegradable (Dr. Muller, 1999).