Trisodium bis[4-[4,5-dihydro-4-[(2-hydroxy-5-nitrophenyl)azo]-3-methyl-5-oxo-1H-pyrazol-1-yl]benzene-1-sulphonato(3-)]cobaltate(3-)

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 August 29th to September 26th, 1989

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

Details on the read-across are available in section 13.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test)

Deviations:

yes

Remarks:

sterilization instead of steril filtration; determination of bacteria concentration: by plating; inoculum: effluent of a domestic sewage treatment plant

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 A (old version) (Ready Biodegradability: Modified AFNOR Test)

Principles of method if other than guideline:

SOP MBA 001 02, with modification of inoculum: effluent of a domestic sewage treatment plant

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

Mixture of polyvalent bacteria collected on 29.08.89, effluent of a domestic sewage treatment plant (ARA-Rhein).
Bacteria concentration:5 × 10^5/ml

Duration of test (contact time):

28 d

Details on study design:

Test concentration: 40 mg/l DOC nominal
Water/ nutrient: according to the specification of the EEC Annex V, Part. C.4 resp. OECD method 301A.
Temperature: 23 ± 1°C
Duration: 28 days
Lighting: indirect daylight
Estimation technique: TOC/DOC
SHIMADZU TOC-500

Reference substance:

other: glucose

Parameter:

% degradation (DOC removal)

Value:

0

Sampling time:

28 d

Remarks on result:

other: DOC removal was 0 in the three replicates

Results with reference substance:

Biodegradation corrected by the blank control and measured as DOC (mg/i) is: 100 % (28th day)

The measured was done in triplicate.

0 %DOC Removal (corrected by the blank control)	% DOC removal after . . . days
	Flask	3	7	14	28
	1	0	0	0	0
	2	0	0	0	0
	3	0	0	0	0
	13	89.0	91.6	85.3	100
	14	47.5	47.6	43.6	40.8

Flask 1,2,3: test material and inoculum

Flask 13: test material, glucose and inoculum (glucose control)

Flask 14: test material, glucose and inoculum (inhibitory action)

Validity criteria fulfilled:

no

Remarks:

pH and detailed concentration of the medium are missing

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance is not readily biodegradable. No inhibition on the activity of the bacteria can be found (degradation of the reference substance > 95 %)

Executive summary:

The determination of biodegradation in percent of DOC (Dissolved Organic Carbon) was evaluated on the test substance. Modifications to the guideline were applied: sterilization instead of steril filtration; determination of bacteria concentration: by plating; type of inoculum: effluent of a domestic sewage treatment plant.

Test substance was found to be not readily biodegradable under the conditions of the test. Biodegradation corrected by blank control and measured as DOC (mg/l) was 0 % (on day 28).

Description of key information

Not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

No experimental study is available to assess biodegradation in water of Acid Brown 303. Available data on a structural analogue, i.e. Similar Substance 01, was used in a read-across approach. Details on the read-across are available in section 13.

The biodegradability of Similar Substance 01 was assessed according to EU method C.4 -A (Dissolved Organic Carbon (DOC) Die-Away Test), for 28 days.

The tested substance was found to be not readily biodegradable, based on a DOC removal of 0 % after 28 days.