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Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
17-01-2018 - 07-03-2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
Experimental result using OECD guidelines.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guideline
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 2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1Hbenzimidazolium chloride.
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride
EC Number:
249-694-9
EC Name:
2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride
Cas Number:
29556-33-0
Molecular formula:
C22H24N3O2.Cl
IUPAC Name:
2-[7-(diethylamino)-2-oxo-2H-chromen-3-yl]-1,3-dimethyl-2,3-dihydro-1H-3,1-benzimidazol-1-ium chloride
Test material form:
solid: particulate/powder
Details on test material:
- Name of test material (as cited in study report): 2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride
- Molecular formula: C22H24N3O2.Cl
- Molecular weight: 397.904 g/mol
- Smiles notation: c1([n+](c2c(n1C)cccc2)C)c1c(oc2c(c1)ccc(c2)N(CC)CC)=O.[ClH-]
- InChl: 1S/C22H24N3O2.ClH/c1-5-25(6-2)16-12-11-15-13-17(22(26)27-20(15)14-16)21-23(3)18-9-7-8-10-19(18)24(21)4;/h7-14H,5-6H2,1-4H3;1H/q+1;/p-1
- Substance type: Organic
- Physical state: Solid
Specific details on test material used for the study:
- Name of test material (as cited in study report): 2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride
- Molecular formula: C22H24N3O2.Cl
- Molecular weight: 397.904 g/mol
- Smiles notation: c1([n+](c2c(n1C)cccc2)C)c1c(oc2c(c1)ccc(c2)N(CC)CC)=O.[ClH-]
- InChl: 1S/C22H24N3O2.ClH/c1-5-25(6-2)16-12-11-15-13-17(22(26)27-20(15)14-16)21-23(3)18-9-7-8-10-19(18)24(21)4;/h7-14H,5-6H2,1-4H3;1H/q+1;/p-1
- Substance type: Organic
- Physical state: Solid

Study design

Oxygen conditions:
not specified
Inoculum or test system:
other: Mixed inoculum
Details on inoculum:
Mixed Inoculum Preparation: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 as 107 to 108 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 test substance concentration
Initial conc.:
0.5 other: ml/125 ml
Based on:
test mat.
Parameter followed for biodegradation estimation
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
Reference substance:
other: Sodium Benzoate

Results and discussion

% Degradation
Parameter:
% degradation (O2 consumption)
Value:
40.6
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 0.8 mgO2/mg. ThOD was determined by calculation as 1.97 mgO2/mg. % Degradation was calculated using the values of BOD and ThOD for test item and was determined to be 40.6 % at 20 ± 1°C. The % degradation of procedure control (reference item) was also calculated using the values of BOD & ThOD and was determined to be 72.28 % at 20 ± 1°C. Degradation of Sodium Benzoate exceeds 45.18 % on 7 days & 59.03 % on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid.

BOD5 / COD results

Results with reference substance:
Degradation of Sodium Benzoate exceeds 45.18% on 7 days & 59.03% on 14th day. The % degradation of procedure control (reference item) was also calculated using the values of BOD & ThOD and was found to be 72.28 % at 20 ± 1°C.

Any other information on results incl. tables

TABLE 1

D.O Values(mg/L)

No.of Days

Inoculum Blank(Control)

Test Suspension

Procedure Control (Reference Item)

0

7.1

7

7.1

7

6.7

5

3.7

14

6.5

4.7

2.6

21

6.2

4.1

1.1

28

5.9

3.1

0.7

35

5.3

2.6

0.4

42

5.1

1.8

0.3

 

TABLE 2

BOD values (mgO2/mg)

No. of Days

Test Suspension

ProcedureControl (Reference Item)

 

 

 

0

0

0

7

0.4

0.75

14

0.43

0.98

21

0.5

1.27

28

0.67

1.3

35

0.65

1.22

42

0.8

1.2

 

 

TABLE 3

PERCENT BIODEGRDATION RESULTS

 

No. of Days

Test Suspension

Procedure Control

(Reference Item)

0

0%

0%

7

20.3%

45.18%

14

21.82%

59.03%

21

25.38%

76.5%

28

34.01%

78.31%

35

32.99%

73.49%

42

40.6%

72.28%

 

Table 4

BOD42, THOD AND % BIODEGRADATION VALUES

Method details

BOD42(mgO2/mg)

ThOD(mgO2/mg)

%Biodegradation

Test Item

0.8

1.97

40.6

Reference Item

1.2

1.66

72.28

 

TABLE 5

pH OF CLOSED BOTTLE TEST

No.of Days

Inoculum Blank (Control)

Test Suspension

Procedure Control (Reference Item)

0

7.3

6.9

7.3

7

6.5

7.1

6.5

14

6.9

7.1

6.8

21

6.9

7

6.8

28

6.7

6.8

6.6

35

6.8

7

6.7

42

6.7

6.6

6.5

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
inherently biodegradable
Conclusions:
The test chemical 2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride(CAS No.29556-33-0) undergoes 40.6 % biodegradation after 42 days in the test condition. Thus, the test chemical was considered to be ultimate inherently biodegradable in nature.
Executive summary:

 An experiment was performed by using 42-days Closed Bottle test following the OECD guideline 301 D to determine the ready biodegradability of the test chemical 2-[7-(diethylamino)-2-oxo- 2H-1-benzopyran-3-yl]-1,3-dimethyl-1H-benzimidazolium chloride, CAS No. 29556-33-0. 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 4 mg/L, while that of inoculum was 32 ml/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 BOD42 value of 2-[7-(diethylamino)-2-oxo-2H-1-benzopyran-3-yl]-1,3-dimethyl-1Hbenzimidazolium chloride was observed to be 0.8 mgO2/mg. ThOD was calculated as 1.97 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 40.6%. The % degradation of procedure control (reference item) was also calculated using the values of BOD & ThOD and was determined to be 72.28 % at 20 ± 1°C. Degradation of Sodium Benzoate exceeds 45.18 % on 7 days & 59.03 % on 14th day. The activity of the inoculum is thus verified and the test can be considered as valid. Based on the results, the test item, under the test conditions, was considered to be ultimate inherently biodegradable in nature.