5',5'''-[ethylenebis(p-phenyleneazo)]bis[1',2'-dihydro-6'-hydroxy-4'-methyl-2'-oxo-1,3'-bipyridinium] dilactate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

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

Adequacy of study:

key study

Study period:

From 12th August to 09th September, 1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

The test substance is the acid form of the substance under registration; justification for read-across is detailed in the IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 C (Inherent Biodegradability: Modified MITI Test (II))

GLP compliance:

not specified

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source: activated sewage was prepared by sampling 10 different sites around the UK, in accordance with OECD guideline 302C.
- Preparation: the mixed sludge was fed daily with a 0.1 % synthetic sewage and maintained on constant aeration at 25 ± 1 °C.
- Initial cell/biomass concentration: equivalent to 100 mg dry weight/l.

Duration of test (contact time):

28 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Parameter followed for biodegradation estimation:

TOC removal

Details on study design:

TEST CONDITIONS
- Test temperature: 25 ± 1 °C
- Agitation: bu magnetic stirrers.
- Lighting: the test was carried out in darkness.

OBSERVATIONS
Manometer volumes were recorded daily.

Reference substance:

aniline

Remarks:

100 mg/l

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Parameter:

% degradation (TOC removal)

Remarks on result:

not determinable

Remarks:

due to the test material adsorbing to the sludge

Details on results:

Test item attained negligable degradation within 28 days calculated from oxygen uptake (% of COD) and therefore, cannot be considered as inherently biodegradable under the strict terms and conditions of the OECD Guidelines.
A COD value of 1.28 mg O2/mg was obtajned for the test material.
TOC analysis of test item was not possible due to the test material adsorbing to the sewage sludge.

Results with reference substance:

Total organic carbon analysis of the test media at Day 0 and Day 28 showed that Aniline attained 100 % within 28 days.
Aniline attained 73 % after 14 days, thereby confirming the suitability of the inoculum and culture conditions.

All percentages of biodegradation values have been corrected for blank values.

Day	% biodegradation
	Test item	Aniline
1	0	0
2	0	0
3	0	0
4	0	0
5	0	0
6	0	2
7	0	20
8	0	30
9	0	45
10	0	43
11	0	46
12	5	50
13	0	65
14	0	73
15	0	75
16	0	74
17	0	71
18	0	77
19	0	84
20	0	71
21	0	72
22	0	70
23	0	70
24	0	70
25	0	70
26	0	72
27	0	70
28	0	68

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The substance is not inherently biodegradable.

Executive summary:

The assessment of the inherently biodegradability potential of the test item was investigated according to the OECD guideline 302C, Modified MITI (II) method. Oxygen consumption was measured by direct manometer reading.

The reference compound, aniline, attained 73 % of degradation after 14 days, confirming the suitability of the inoculum and culture conditions.

Test item attained negligable degradation within 28 days calculated from oxygen uptake (% of COD) and therefore, cannot be considered as inherently biodegradable under the strict terms and conditions of the OECD Guidelines. A COD value of 1.28 mg O2/mg was obtajned for the test material. TOC analysis of test item was not possible due to the test material adsorbing to the sewage sludge.

Conclusion

The substance is not inherently biodegradable.

Description of key information

Neither readily nor inherently biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The substance is an azo dye, salified with lactate. Basic Yellow 094 is not expected to be ready biodegradable because of its chemical structure and the specific function. Commonly, dyes undergo a primary transformation, i.e. discolouration due to the interrupting the conjugation. Nevertheless, the degradation process involves more steps and takes more time.

There are no information about the biodegradability potential of Basic Yellow 094, thus available information on the structural analogue Similar Substance 01 have been taken into consideration. Similar Substance 01 is the acid form of Basic Yellow 094; the read across approach can be considered as appropriate and suitable to assess the property under investigation (details about the approach are reported into the IUCLID section 13).

The assessment of the inherently biodegradability potential of Similar substance 01 was investigated according to the OECD guideline 302C, Modified MITI (II) method. Test item attained negligable degradation, within 28 days, calculated from oxygen uptake (% of COD); therefore, it cannot be considered as inherently biodegradable under the strict terms and conditions of the OECD guidelines. A COD value of 1.28 mg O₂/mg was obtajned for the test material. TOC analysis of test item was not possible as test material adsorbed to the sewage sludge.