Disodium benzene-1,3-disulphonate

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 OECD guidelines.

Qualifier:

according to guideline

Guideline:

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

Principles of method if other than guideline:

Biodegradation study was conducted according to OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test) for evaluating the percentage biodegradability of test substance.

GLP compliance:

no

Oxygen conditions:

not specified

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):

28 d

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:

other: Sodium Benzoate

Parameter:

% degradation (O2 consumption)

Value:

68.88

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 arereported in Tables 2 and 3, respectively.The BOD28 value of Disodium benzene-1,3-disulphonate(CAS No.831-59-4) was observed to be 0.62 mgO2/mg. ThOD was determined by calculation as 0.9 mgO2/mg. % Degradation was calculated using the values of BOD and ThOD for test item and was found to be 68.88% at 20 ± 1°C. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was found to be 70.48%.Degradation of Sodium Benzoate exceeds 46.38% on 7 days & 60.24% 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 item) was also calculated using BOD & ThOD and was found to be 70.48%.Degradation of Sodium Benzoate exceeds 46.38% on 7 days & 60.24% 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	Inoculum Blank (Control)	Test Suspension	Procedure Control (Reference Item)
0	6.6	6.4	6.5
7	6.3	5	3.1
14	6.1	4.1	2
21	5.8	3.6	1.2
28	5.5	2.8	0.7

TABLE 2:

BOD values (mgO2/mg)

No. of Days	Test Suspension	Procedure Control (Reference Item)
0	0	0
7	0.27	0.77
14	0.45	1
21	0.5	1.12
28	0.62	1.17

 

TABLE 3:

PERCENT BIODEGRDATION RESULTS

No. of Days	Test Suspension	Procedure Control (Reference Item)
0	0%	0%
7	30%	46.38%
14	50%	60.24%
21	55.55%	67.46%
28	68.88%	70.48%

 

Table 4:

BOD28, THOD AND % BIODEGRADATION VALUES

Method details	BOD28 (mgO2/mg)	ThOD (mgO2/mg)	% Biodegradation
Test Item	0.62	0.9	68.88
Reference Item	1.17	1.66	70.48

 

Validity criteria fulfilled:

yes

Interpretation of results:

other: readily biodegradable

Conclusions:

The test item disodium benzene-1,3-disulphonate (831-59-4) undergoes 68.88 % biodegradation after 28 days in the test condition. Thus, the test item was considered to be readily biodegradable.

Executive summary:

28-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test item disodium benzene-1,3-disulphonate (831-59-4). The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study. 1 polyseed capsule were 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. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4mg/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 item) was also calculated using BOD & ThOD and was determined to be 70.48%. Degradation of Sodium Benzoate exceeds 46.38% on 7 days & 60.24% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.62 mgO2/mg. ThOD was calculated as 0.9 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 68.88%. Based on the results, the test item disodium benzene-1,3-disulphonate (831-59-4), under the test conditions, was considered to be readily biodegradable in nature.

Description of key information

The test item disodium benzene-1,3-disulphonate (831-59-4) undergoes 68.88 % biodegradation after 28 days in the test condition. Thus, the test item was considered to be readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Various experimental studies for the target compound disodium benzene-1,3 -disulfonate (CAS No. 831 -59 -4) and various supporting weight of evidence studies for its read across substances were reviewed for the biodegradation end point which are summarized as below:

In an experimental study,28-days Closed Bottle test following the OECD guideline 301 D was performed to determine the ready biodegradability of the test item disodium benzene-1,3-disulphonate (831-59-4). The study was performed at a temperature of 20°C. The test system included control, test item and reference item. Polyseed were used for this study. 1 polyseed capsule were 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. The concentration of test and reference item (Sodium Benzoate) chosen for both the study was 4mg/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 item) was also calculated using BOD & ThOD and was determined to be 70.48%. Degradation of Sodium Benzoate exceeds 46.38% on 7 days & 60.24% on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. The BOD28 value of test chemical was observed to be 0.62 mgO2/mg. ThOD was calculated as 0.9 mgO2/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to Closed Bottle test was determined to be 68.88%. Based on the results, the test item disodium benzene-1,3-disulphonate (831-59-4), under the test conditions, was considered to be readily biodegradable in nature.

 

In a weight of evidence study from authoritative database (GSBL, 2017) for the target chemicaldisodium benzene-1,3-disulfonate(CAS No. 831-59-4), biodegradation experiment was conducted for 28 days for evaluating the percentage biodegradability of test substance disodium benzene-1,3 –disulfonate. The study was performed according to OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test). The activated sludge was used as a test inoculum obtained from the biological purification plant. Concentration of inoculum i.e, sludge used was 1100 mg/l and initial test substance conc. used in the study was 50 - 400 mg/l based on DOC concentration and 200 – 1000 mg/l based on COD concentration, respectively. Mineral medium was used for the study. Duration of acclimatization phase was 7 – 10 days and duration of logarithmic degradation was 7 – 9 days. The percentage degradation of test substance was determined to be 88 and 97% degradation by DOC removal parameter in 21 and 28 days, respectively. Thus, based on percentage degradation, disodium benzene-1,3 -disulfonate is considered to be readily biodegradable in nature.

 

In an another study, biodegradation experiment was carried out for 19 days for evaluating the percentage biodegradability of test substance disodium benzene-1,3 -disulfonate (CAS no. 831 -59 -4) (GSBL, 2017) . The study was performed according to OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test). The mixed culture was used as a test inoculum obtained from sewage treatment plant. Initial test substance conc. used in the study was 5 - 20 mg/l based on DOC concentration. Mineral medium was used for the study. The percentage degradation of test substance was determined to be 19.8% by DOC removal parameter in 19 days. Thus, based on percentage degradation, disodium benzene-1,3 -disulfonate is considered to be inherently biodegradable in nature.

For the read across chemical benzene-1,3-disulfonic acid (CAS no. 98-48-6), a batch test in an open system was conducted for evaluating the biodegradability of read across substance Benzene 1,3 disulphonic acid. The compound was the sole source of organic carbon for the microbes of the inoculum. Degradation was studied by determining COD (organic carbon). The pH of the biological medium was 7.2. Initial concentration; 125 - 200mg/l COD. Inoculum; Activated sludge, adapted for 20 days, fed by glucose and peptone with simultaneous addition of the substance tested in the concentration up to 125 mg/l. The sludge age was 5 days. Concentration of the inoculum; 100mg/l. Average temperature during the experiment; 20°C. The percentage degradation of read across substance was determined to be 63.5% degradation by COD parameter in 5 days. Thus, based on percentage degradation, substance Benzene 1,3 disulphonic acid was considered to be readily biodegradable in nature.

 

On the basis of above results for target chemical disodium benzene-1,3-disulfonate (from CRO lab and GSBL authoritative database) and for its read across substance (from peer reviewed journal), it can be concluded that the test substance disodium benzene-1,3-disulfonate can be expected to be readily biodegradable in nature.