Denatonium benzoate

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 study using one of the recommended OECD guidelines.

Qualifier:

according to guideline

Guideline:

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

Principles of method if other than guideline:

Biodegradation study was conducted according to OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test) for evaluating the percentage biodegradability of test substance N-benzyl-2-[(2,6-dimethylphenyl)amino]-N,N-diethyl-2-oxoethanaminium benzoate hydrate (CAS no. 3734-33-6).

GLP compliance:

not specified

Specific details on test material used for the study:

- Name of test material (as cited in study report): N-benzyl-2-[(2,6-dimethylphenyl)amino]-N,N-diethyl-2-oxoethanaminium benzoate hydrate
- Molecular formula: C21H29N2O.C7H5O2
- Molecular weight: 446.58 g/mol
- Smilies notation: CC[N+](CC)(Cc1ccccc1)CC(=O)Nc2c(cccc2C)C.c1ccc(cc1)C(=O)[O-]
- InChl: 1S/C21H28N2O.C7H6O2/c1-5-23(6-2,15-19-13-8-7-9-14-19)16-20(24)22-21-17(3)11-10-12-18(21)4;8-7(9)6-4-2-1-3-5-6/h7-14H,5-6,15-16H2,1-4H3;1-5H,(H,8,9)
- Substance type: organic
- Physical state: White granular solid

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

Mixed Inoculum Preparation (In-House): 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:

other: BOD and ThOD

Key result

Parameter:

other: BOD

Value:

18.17

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 Denatonium benzoate (CAS No. 3734-33-6) was observed to be 0.436 mgO2/mg. ThoD was determined by calculation as 2.40 mgO2/mg. % Degradation was calculated using the values of BOD and ThOD for test item and was found to be 18.17%. The % degradation of procedure control (reference item) was also calculated using BOD & ThOD and was found to be 51.39%.

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).
Degradation of Sodium benzoate exceeds 44.16% after 7 days and 50.24% after 14 days. The activity of the inoculums is thus verified and the test can be considered as valid.

Results with reference substance:

Degradation of Sodium benzoate exceeds 44.16% after 7 days and 50.24% after 14 days. The activity of the inoculums is thus verified and the test can be considered as valid.

BOD₂₈, THOD AND % BIODEGRADATION VALUES

Method details	BOD28(mgO2/mg)	ThOD (mgO2/mg)	% Biodegradation
Test Item	0.436 mgO2/mg	2.40 mgO2/mg	18.17 %
Reference Item	0.853 mgO2/mg	1.66 mgO2/mg	51.39 %

Validity criteria fulfilled:

yes

Interpretation of results:

under test conditions no biodegradation observed

Conclusions:

The test item Denatonium benzoate (CAS No. 3734-33-6) undergoes 18.17% biodegradation after 28 days in the test condition. Thus, the test item can be inferred as non-biodegradable.

Executive summary:

28-days Manometric respirometry test following the OECD guideline 301F to determine the ready biodegradability of the test item Denatonium benzoate (CAS No. 3734-33-6) was conducted. 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 Denatonium benzoate (CAS No. 3734-33-6) was observed to be 0.436 mgO₂/mg. ThOD was calculated as 2.40mgO₂/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was determined to be 18.17%. Based on the results, the test item, under the test conditions, was considered to be non-biodegradable at 20 ± 1°C over a period of 28 days.

Description of key information

28-days Manometric respirometry test following the OECD guideline 301F to determine the ready biodegradability of the test item Denatonium benzoate (CAS No. 3734-33-6) was conducted. 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 Denatonium benzoate(CAS No. 3734-33-6) was observed to be 0.436 mgO2/mg. ThOD was calculatedas 2.40mgO2/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 18.17%. Based on the results, the test item, under the test conditions, was found to be non-biodegradable at 20 ± 1°C over a period of 28 days.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

Experimental study was done by UERL laboratory (2015) in this study a 28-days Manometric respirometry test following the OECD guideline 301F was done to determine the ready biodegradability of the test item Denatonium benzoate (CAS No. 3734-33-6) . 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 ofDenatonium benzoate (CAS No. 3734-33-6) was observed to be 0.436 mgO₂/mg. ThOD was calculatedas 2.40mgO₂/mg. Accordingly, the % degradation of the test item after 28 days of incubation at 20 ± 1°C according to manometric respirometry test was obtained to be 18.17%. Based on the results, the test item, under the test conditions, was considered to be non-biodegradable at 20 ± 1°C over a period of 28 days.