Reaction products of diazotised sodium 2-amino-5-{[2-(sulfonatooxy)ethyl]sulfonyl}benzenesulfonate coupled with sodium 2-(4-aminobenzene-1-sulfonyl)ethyl sulfate, subsequently coupled with diazotised sodium 2-(4-aminobenzene-1-sulfonyl)ethyl sulfate

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 result using 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:

activated sludge, domestic, adapted

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):

28 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:

59.38

Sampling time:

28 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 BOD28 value of test chemicl was observed to be 0.48 mgO2/mg. ThOD was determined by calculation as 0.8 mgO2/mg. % Degradation was calculated using the values of BOD and ThOD for test chemical and was determine to be 59.38% at 20 ± 1°C. The % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was observed to be 93.75%. Degradation of Sodium Benzoate exceeds 40.63% on 7 days & 90.63% on 14th day. The activity of the inoculum was 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 observed to be 93.75%. Degradation of Sodium Benzoate exceeds 40.63% on 7 days & 90.63% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid.

TABLE 1

D.O VALUES (mg/L)

No. of Days	Blank Control	Test Chemical	Procedure Control(Reference Chemical)	Toxicity Control
0	7.5	7.5	7.5	7.4
7	7.3	6.3	4.3	5.9
14	7.1	5.4	1.9	4.1
21	6.7	4.9	1.1	3.7
28	6.4	4.5	0.7	3.3

 

TABLE 2

BOD VALUES (mgO₂/mg)

No. of Days	Test Chemical	Procedure Control(Reference Chemical)	Toxicity Control
0	0	0	0
7	0.250	0.750	0.330
14	0.425	1.300	0.730
21	0.450	1.400	0.730
28	0.475	1.425	0.750

 

TABLE 3

% BIODEGRADATION

No. of Days	Test Chemical	Procedure Control(Reference Chemical)	Toxicity Control
0	0	0	0
7	31.25	44.91	40.63
14	53.13	77.84	90.63
21	56.25	83.83	90.63
28	59.38	85.33	93.75

 

TABLE 4

BOD28, ThOD AND % BIODEGRADATION VALUES

Test System	BOD28	ThOD (mgO2/mg)	% Biodegradation
Test Chemical	0.48	0.8	59.38
Procedure Control(Reference Chemical)	1.43	1.67	85.63
Toxicity Control	0.75	0.8	93.75

 

TABLE 5

pH VALUES

No. of Days	Blank Control	Test Chemical	Procedure Control(Reference Chemical)	Toxicity Control
0	7.4	7.4	7.4	7.4
7	7.3	7.4	7.3	7.3
14	7.3	7.2	7.2	7.2
21	7.2	7.1	7.2	7.1
28	7.1	7.0	7.2	7.1

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

The test chemical, undergoes 59.38% biodegradation after 28 days in the test condition.

Executive summary:

The closed bottle test following the OECD guideline 301 D was performed 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 chemical. Polyseed were used as inoculum at concentration of 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. The initial concentration of test chemical and reference chemical (Sodium Benzoate) used was 4 mg/L, and the concentration of inoculum used was 32 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference chemical was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test chemical and reference chemical. The % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was observed to be 93.75%. Degradation of Sodium Benzoate exceeds 40.63% on 7 days & 90.63% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.48 mgO2/mg. ThOD was determined by calculation as 0.8 mgO2/mg. On the basis of ThOD and BOD 28 value the percent degradation of the test chemical was determined to be 59.38%. Based on the percent degradation value it is concluded that the test chemical is considered as, inherently biodegradable in water.

Description of key information

The test chemical undergoes 59.38% biodegradation after 28 days in the test condition. Thus, the test chemical was considered to be inherently biodegradable in water.

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

Different experimental studies for the Biodegradation in water endpoint were reviewed for the test substance  and are summarised below:

 

The first study includes closed bottle test following the OECD guideline 301 D was performed 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 chemical. Polyseed were used as inoculum at concentration of 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. The initial concentration of test chemical and reference chemical (Sodium Benzoate) used was 4 mg/L, and the concentration of inoculum used was 32 ml/l. OECD mineral medium was used for the study. ThOD (Theoretical oxygen demand) of test and reference chemical was determined by calculation. % degradation was calculated using the values of BOD and ThOD for test chemical and reference chemical. The % degradation of procedure control (reference chemical) was also calculated using BOD & ThOD and was observed to be 93.75%. Degradation of Sodium Benzoate exceeds 40.63% on 7 days & 90.63% on 14th day. The activity of the inoculum was thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.48 mgO2/mg. ThOD was determined by calculation as 0.8 mgO2/mg. On the basis of ThOD and BOD 28 value the percent degradation of the test chemical was determined to be 59.38%. Based on the percent degradation value it is concluded that the test chemical is considered as inherently biodegradable in water.

 

The second study of biodegradation in water was carried out. The duration of test was 28 days. The inoculum was taken as activated sludge. The concentration of sludge was taken as 30 mg/L. The initial concentration of test chemical was taken as 100 mg/l. The study design was taken as standard type. The percent biodegradation of test chemical was determined to be 4% by O2 consumption parameter, 7 % by TOC parameter and 96 % by HPLC method. Based on the percent degradation value it is concluded that the test chemical is not readily biodegradable in water.

 

On the basis of the above-mentioned information, the test chemical was considered as not readily biodegradable in water.