2-Naphthalenesulfonic acid, 7-amino-4-hydroxy-3-[[2-methoxy-5-methyl-4-[[2-(sulfooxy)ethyl]sulfonyl] phenyl]azo]-8-[[2-sulfo-4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-, tetrasodium salt

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Experimental result using standard OECD guidelines.

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

GLP compliance:

no

Oxygen conditions:

aerobic

Inoculum or test system:

other: Mixed inoculum

Details on inoculum:

Mixed Inoculum Preparation: Polyseed were used for this study. 1 polyseed capsule was added in 500 ml D.I water and then stirred for 1 hour for proper mixing and functioning of inoculum. This gave the bacterial count as 10E7 to 10E8 CFU/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):

42 d

Initial conc.:

4 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: OECD mineral medium was used for the study
- Test temperature: 20°C
- Continuous darkness: Yes
- Other: The water used in this study is deionized water.

TEST SYSTEM
- Culturing apparatus: The apparatus used in this study is BOD bottles; with glass stoppers (125 ml), BOD incubator & oxygen electrode and meter.

CONTROL AND BLANK SYSTEM
- Inoculum blank: it contains only test inoculum
- Procedure control: contains reference compound and inoculum

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

39.21

Sampling time:

42 d

Remarks on result:

other: Other details not known

Details on results:

The oxygen consumed by the test systems was corrected for oxygen consumption occurring in the blank test systems. The BOD Values (mgO2/mg) and percent biodegradation results for each test system are reported in Tables 2 and 3, respectively. The BOD42 value of test chemical was observed to be 0.4 mgO2/mg. ThOD was determined by calculation as 1.02 mgO2/mg. % degradation was calculated using the values of BOD and ThOD for test chemical and was determined to be 39.21% at 20 ± 1°C. The % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was determined to be 66.26%. Degradation of Sodium Benzoate exceeds 70.48% on 7 days & 73.49% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid.

Results with reference substance:

The % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was determined to be 66.26%. Degradation of Sodium Benzoate exceeds 70.48% on 7 days & 73.49% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid.

TABLE 1: D.O Values (mg/L)

No. of Days	Inoculum Blank (Control)	Test Suspension	Procedure Control (Reference Item)
0	6.8	6.7	6.7
7	6.5	5.5	1.7
14	6.3	4.9	1.2
21	6	4.6	0.8
28	5.6	3.9	0.7
35	5.3	3.7	0.6
42	5.1	3.4	0.6

TABLE 2: BOD Values (mg O2/mg)

 

No. of Days	Test Suspension	Procedure Control (Reference Item)
0	0	0
7	0.22	1.17
14	0.32	1.22
21	0.32	1.27
28	0.4	1.2
35	0.37	1.15
42	0.4	1.1

 

TABLE 3: PERCENT BIODEGRDATION RESULTS

No. of Days	Test Suspension	Procedure Control (Reference Item)
0	0%	0%
7	21.56%	70.48%
14	31.37%	73.49%
21	31.37%	76.5%
28	39.21%	72.28%
35	36.27%	69.27%
42	39.21%	66.26%

 

Table 4: BOD42, THOD AND % BIODEGRADATION VALUES

 

Method details	BOD42(mgO2/mg)	ThOD (mgO2/mg)	%Biodegradation
Test Item	0.40	1.02	39.21
Reference Item	1.10	1.66	66.26

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

The test chemical undergoes 39.21% biodegradation after 28 days in the test condition. Thus, the test chemical was considered to be inherently biodegradable.

Executive summary:

Biodegradation study was conducted for 42-days in accordance with the OECD guideline 301 D to determine the ready biodegradability of the test chemical. The study was performed at a temperature of 20°C. The test system included control, test chemical and reference substance. Polyseed were used as a test inoculum for the study. The concentration of test and reference chemical (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. 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 % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was determined to be 66.26%. Degradation of Sodium Benzoate exceeds 70.48% on 7 days & 73.49% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid.The BOD42 value of test chemical was observed to be 0.4 mgO2/mg. ThOD was calculated as 1.02 mgO2/mg. Accordingly, the % degradation of the test chemical after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 39.21%. Based on the results, the test chemical, under the test conditions, was considered to be inherently biodegradable in nature.

Description of key information

Biodegradation study was conducted for 42-days in accordance with the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2019). The study was performed at a temperature of 20°C. The test system included control, test chemical and reference substance. Polyseed were used as a test inoculum for the study. The concentration of test and reference chemical (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. 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 % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was determined to be 66.26%. Degradation of Sodium Benzoate exceeds 70.48% on 7 days & 73.49% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD42 value of test chemical was observed to be 0.4 mgO2/mg. ThOD was calculated as 1.02 mgO2/mg. Accordingly, the % degradation of the test chemical after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 39.21%. Based on the results, the test chemical, under the test conditions, was considered to be inherently biodegradable in nature.

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Additional information

Biodegradation study was conducted for 42-days in accordance with the OECD guideline 301 D to determine the ready biodegradability of the test chemical (Experimental study report, 2019). The study was performed at a temperature of 20°C. The test system included control, test chemical and reference substance. Polyseed were used as a test inoculum for the study. The concentration of test and reference chemical (Sodium Benzoate) chosen for both the study was 4 mg/L, while that of inoculum was 32 ml/l. OECD mineral medium was used for the study. 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 % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was determined to be 66.26%. Degradation of Sodium Benzoate exceeds 70.48% on 7 days & 73.49% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD42 value of test chemical was observed to be 0.4 mgO2/mg. ThOD was calculated as 1.02 mgO2/mg. Accordingly, the % degradation of the test chemical after 42 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 39.21%. Based on the results, the test chemical, under the test conditions, was considered to be inherently biodegradable in nature.