Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental test result performed using standard OECD test guidelines

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: Domestic waste water, surface soil and soil samples from polluted sites receiving predominantly domestic waste

Details on inoculum:

Domestic waste water, surface soil and soil samples from polluted sites receiving predominantly domestic waste was collected and were mixed to get diluted suspension. The inoculum was kept aerobic until being used for experiment by supplying organic and inorganic sources required by micro flora to sustain at controlled laboratory conditions. This gave the bacterial count as107to 108CFU/ml. At the regular interval microbial plating was also performed on agar to confirm the vitality and CFU count of microorganism.

Duration of test (contact time):

28 d

Initial conc.:

100 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

1. Respirometer flasks were allowed to reach the desired temperature at 200C.The test item, i.e., disodium4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate, was taken at a concentration of 100mg/L in mineral medium. The reference item chosen was Sodium benzoate with a concentration of 100mg/L in the mineral medium was directly added to the Respirometer Flask according the volume of mineral media taken.
2. The Respirometer Flasks of test item & reference item were filled with 400ml and 250ml of mineral media, respectively. Test suspension volume was decided by considering the available information on biodegradability of that test item.
3. All the Respirometer Flasks were inoculated with prepared mixed inoculum at the concentration of 10ml/L. This concentration gave the bacterial CFU/ml as 107to 108.
4. The initial pH of the test medium was 7.4. The pH of all test vessels was measured at 28th day.
5. 2-4 pellets of KOH was added in the alkali holder, which acts as CO2 absorber.
6. The respirometric sensors containing the KOH pellets were tightly and carefully screwed on each of the Respirometer Flasks. The sensors were reset by deleting old recorded data and choosing the appropriate scale (The sensor gives the oxygen consumption values in mgO2/l).
7. Respirometer Flask were kept in the respirometer incubator at constant temperature of 20 ± 1°C for 28 days.
8. Every day oxygen consumption (mg O2/l) into the each bottle was recorded. Temperature and stirring condition were checked regularly.

Reference substance:

benzoic acid, sodium salt

Remarks:

concentration 100 mg/L

Key result

Parameter:

% degradation (O2 consumption)

Value:

2.8

Sampling time:

28 d

Details on results:

The BOD28 value of disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate (CAS No. 4553-89-3) was observed to be 0.0385 mgO2/mg. ThoD was determined by calculation as 1.373 mgO2/mg. % Degradation was calculated using the values of BOD and ThOD for test item and was found to be 2.80 %. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was found to be 77.36%.

The mean BOD values (mg O2/l) in control on 28th day was 28.2 mg O2/l, thereby fulfilling the control validity criteria (i.e., The oxygen consumption of the inoculum blank is normally 20-30 mg O2/l and should not be greater than 60 mg/l in 28 days).

Results with reference substance:

The percentage degradation of reference substance (Sodium benzoate) has reached the pass levels (60% of its ThOD) by Day 14. Thus, fulfilling the validity criteria of the study.

TABLE 1: MEAN RESPIROMETRIC VALUES (oxygen consumed mg O2/l)

No. of Days	Inoculum Blank (Control)	Test Suspension	Procedure Control (Reference Item)
1	11.4	12	26.5
2	15.6	16.1	26.5
3	20	20.5	23
4	24.1	26.5	40
5	24.3	27.3	70.5
6	26.3	29.3	100.5
7	26.2	29.5	108
8	26.5	29.8	120.5
9	-	-	-
10	-	-	-
11	26.8	30.6	127
12	26.2	29.8	133
13	26.8	30.4	142.5
14	-	-	-
15	27.1	30.6	144.5
16	27.1	30.9	146.5
17	-	-	-
18	27.1	30.9	150
19	27.3	30.9	152
20	27.6	31.5	154.5
21	27.1	30.9	154.5
22	27.6	31.5	155.5
23	27.6	31.8	155
24	27.9	32.05	156.5
25	-	-	-
26	27.6	31.8	157
27	28.2	32.05	158
28	28.2	32.05	157

TABLE 2: BOD values (mgO₂/mg)

No. of Days	Test Suspension	Procedure Control (Reference Item)
1	0.006	0.156
2	0.005	0.159
3	0.005	0.395
4	0.024	0.669
5	0.03	0.672
6	0.03	0.712
7	0.033	0.7333
8	0.033	0.78
9	-	-
10	-	-
11	0.038	0.79
12	0.036	0.808
13	0.036	0.822
14	-	-
15	0.035	0.834
16	0.038	0.839
17	-	-
18	0.038	0.849
19	0.036	0.847
20	0.039	0.859
21	0.038	0.859
22	0.039	0.869
23	0.042	0.869
24	0.041	0.876
25	-	-
26	0.042	0.879
27	0.038	0.863
28	0.038	0.853

TABLE 3: PERCENT BIODEGRDATION RESULTS

No. of Days	Test Suspension	Procedure Control (Reference Item)
1	0.44	9.07
2	0.36	6.55
3	0.36	1.80
4	1.75	9.55
5	2.18	27.75
6	2.18	44.56
7	2.40	49.13
8	2.40	56.46
9	-	-
10	-	-
11	2.77	60.18
12	2.62	64.14
13	2.62	69.49
14	-	-
15	2.55	70.51
16	2.77	71.71
17	-	-
18	2.77	73.81
19	2.62	74.89
20	2.84	76.22
21	2.77	76.52
22	2.84	76.82
23	3.06	76.52
24	3.02	77.24
25	-	-
26	3.06	77.72
27	2.80	77.96
28	2.80	77.36

Table 4: BOD₂₈, THOD AND % BIODEGRADATION VALUES

Method details	BOD28(mgO2/mg)	ThOD (mgO2/mg)	% Biodegradation
Test Item	0.0385 mgO2/mg	1.373 mgO2/mg	2.80 %
Reference Item	1.288 mgO2/mg	1.665 mgO2/mg	77.36 %

TABLE 5: pH OF RESPIROMETER FLASK

Respirometer Flask	pH on 0^thDay	pH on 28^thDay
Inoculum Blank(Control)         B1	7.4	7.7
B2	7.4	7.7
Test Suspension B1	7.4	7.8
B2	7.4	7.7
Procedure Control B1	7.5	7.7
B2	7.5	7.7

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate (CAS No. 4553-89-3) undergoes 2.80 % biodegradation after 28 days in the test condition. Thus, the test item can be inferred/considered as not readily biodegradable.

Executive summary:

28-days Manometric respirometry test following the OECD guideline 301F to determine the ready biodegradability of disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate(CAS No. 4553-89-3). The test system included control, test item and reference item. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 100mg/L, while that of inoculum was 10ml/l. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % Degradation was calculated using the values of BOD and ThOD for test item and reference item.

The BOD₂₈value of disodium-4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate (CAS No. 4553-89-3) was observed to be 0.0385 mgO₂/mg. ThOD was calculatedas 1.373 mgO₂/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was found to be 2.80%. Based on the results, the test item, under the test conditions, was found to be not readily biodegradable at 20 ± 1°C over a period of 28 days.

Description of key information

The test item disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate (CAS No. 4553-89-3) undergoes 2.80 % biodegradation after 28 days in the test condition. Thus, the test item can be inferred/considered as not readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Data available for target Disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate for the endpoint Biodegradation in water are summarized as follows:

In key study, 28-days Manometric respirometry test following the OECD guideline 301F was conducted to determine the ready biodegradability of disodium 4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate(CAS No. 4553-89-3). The test system included control, test item and reference item. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 100mg/L, while that of inoculum was 10ml/l. ThOD (Theoretical oxygen demand) of test and reference item was determined by calculation. % Degradation was calculated using the values of BOD and ThOD for test item and reference item. The BOD28value of disodium-4,4'-[[2,4-dihydroxy-5-(hydroxymethyl)-1,3-phenylene]bis(azo)]bisnaphthalene-1-sulphonate (CAS No. 4553-89-3) was observed to be 0.0385 mgO2/mg. ThOD was calculatedas 1.373 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was found to be 2.80%. Based on the results, the test item, under the test conditions, was found to be not readily biodegradable at 20 ± 1°C over a period of 28 days.

In supporting study, Estimation Programs Interface Suite (EPI suite, 2017) was run to predict the biodegradation potential of the test compound Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate), CAS No. 4553-89-3, in the presence of mixed populations of environmental microorganisms. The biodegradability of the substance was calculated using seven different models such as Linear Model, Non-Linear Model, Ultimate Biodegradation Timeframe, Primary Biodegradation Timeframe, MITI Linear Model, MITI Non-Linear Model and Anaerobic Model (called as Biowin 1-7, respectively) of the BIOWIN v4.10 software. The results indicate that the test chemical Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) is not expected to be readily biodegradable.

Thus based on available data for target it is concluded that Disodium 4,4’-(2,4-dihydroxy-5- hydroxymethyl-1,3-phenylene bis-azo) di- (naphthalene-1-sulfonate) is not expected to be readily biodegradable in water.