Trisodium 7-[[4-chloro-6-[ethyl[3-[[2-(sulphonatooxy)ethyl]sulphonyl]phenyl]amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[(4-methoxy-2-sulphonatophenyl)azo]naphthalene-2-sulphonate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

From January 14, 1999 to February 11, 1999

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

RA study

Reason / purpose for cross-reference:

read-across: supporting information

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, non-adapted

Details on inoculum:

Mixed population of aquatic microorganisms form secondary effluent of a domestic sewage treatment plant (kläranlage Odenthal)
Treatment given: separation of coarse particles by filtration
Concentration of effluents in reaction mixture: 0.5 mL/L
Pretreatment: none

Duration of test (contact time):

28 d

Initial conc.:

18.6 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

Test temperature: 22°C
Number of flasks: Two each for the test substance and the reference substance and one for the toxicity control

Reference substance:

aniline

Remarks:

purity: 99.5%; initial conc.: 19.6 mg/L DOC

Key result

Parameter:

% degradation (DOC removal)

Value:

18

St. dev.:

0.5

Sampling time:

28 d

Details on results:

% degradation (DOC removal) after 7, 14, 21, 27 and 28 d: 18, 22, 20, 21 and 18, respectively (mean of two flasks).

Results with reference substance:

% degradation (DOC removal) after 28 d for the reference substance (aniline): 96.5
% degradation (DOC removal) after 28 d for the toxicity control: 57

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

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

Executive summary:

A study was conducted to determine the ready biodegradability of the read-across substance in water according to EU Method C.4 -B, in compliance with GLP. Non-adapted activated sludge (domestic) was exposed to the equivalent of 18.6 mg/L DOC of test substance under aerobic conditions. Removal of dissolved organic carbon (DOC) was monitored for 28 d. A blank control and a reference substance (aniline) were kept in the study. The test substance biodegaraded up to 18% by test end. Under the study conditions, the substance was not considered to be readily biodegradable (Müller, 1999).

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

A study was conducted to determine the ready biodegradability of the read-across substance in water according to EU Method C.4 -B, in compliance with GLP. Non-adapted activated sludge (domestic) was exposed to the equivalent of 18.6 mg/L DOC of test substance under aerobic conditions. Removal of dissolved organic carbon (DOC) was monitored for 28 d. A blank control and a reference substance (aniline) were kept in the study. The test substance biodegraded up to 18% by test end. Under the study conditions, the substance was not considered to be readily biodegradable (Müller, 1999).