Denatonium benzoate

Endpoint summary

Description of key information

Stability:

Hydrolysis:

Half life of hydrolysis of test chemical N-benzyl-2-[(2,6-dimethylphenyl)amino]-N,N-diethyl-2-oxoethanaminium benzoate hydrate (CAS no. 3734-33-6) was determined by conducting hydrolysis experiment at different pH and temperatures by using HPLC methods and EPA guideline 161-1. Preliminary test was performed at 50 oC and at pH 4, 7 and 9 for 5 days and less than 10 % hydrolysis was obtained. Then actual test was performed for at temperature 25 oC and pH 5, 7 and 9 and again less than 10 % hydrolysis was obtained. So on the basis of % hydrolysis estimated half life of hydrolysis obtained was greater than 1 year therefore it is concluded that this test chemical shows negligible hydrolysis.

Biodegradation:

Biodegradation in water

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 BOD28 value 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 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.

Biodegradation in water and sediment

Estimation Programs Interface prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 3.77% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 60 days (1440 hrs). The half-life (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high whereas the half-life period of test chemical in sediment is estimated to be 541.66 days (13000 hrs). Based on this half-life value, it indicates that test chemical is persistent in sediment.

Biodegradation in soil

According to this study the test substance Denatonium benzoate is not considered to be a significant degraded substance in 30 days at 15ºC.

Transport and distribution:

Adsorption/desorption:

The adsorption coefficient Koc in soil and in sewage sludge of Denatonium benzoate (powder) (CAS No. 3734-33-6)was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The reference substances were chosen according to estimated K_ocrange of the test substance and generalized calibration graph was prepared. The reference substances were 4 chloroaniline, 4 methylaniline, N methylaniline, 2 Nitrophenol, Nitrobenzene, 4-Nitrobenzamide, N,N-dimethylbenzamide, N-methylbenzamide, Benzamide, phenanthrene having K_ocvalue ranging from 1.239 to 4.09. The Log K_ocvalue was determined tobe 3.392± 0.007at 25°C. On the basis of log Koc value it is concluded that test chemical Denatonium benzoate has strong sorption to soil and sediment and therefore has negligible migration potential to ground water.

Additional information

Stability:

Hydrolysis:

Two different experimental studies have been conducted for target chemical N-benzyl-2-[(2,6-dimethylphenyl)amino]-N,N-diethyl-2-oxoethanaminium benzoate hydrate (CAS no. 3734 -33 -6) for hrydrolysis endpoint and their results are summarized below.

 

In the first experimental study the Half life of hydrolysis of test chemical N-benzyl-2-[(2,6-dimethylphenyl)amino]-N,N-diethyl-2-oxoethanaminium benzoate hydrate (CAS no. 3734-33-6) was determined by conducting hydrolysis experiment at different pH and temperatures by using HPLC methods and EPA guideline 161-1. Preliminary test was performed at 50 oC and at pH 4, 7 and 9 for 5 days and less than 10 % hydrolysis was obtained. Then actual test was performed for at temperature 25 oC and pH 5, 7 and 9 and again less than 10 % hydrolysis was obtained. So on the basis of % hydrolysis estimated half life of hydrolysis obtained was greater than 1 year therefore it is concluded that this test chemical shows negligible hydrolysis.

 

Similarly, in supporting study the experiment was performed to determine percent hydrolysis of test chemical N-benzyl-2-[(2,6-dimethylphenyl)amino]-N,N-diethyl-2-oxoethanaminium benzoate hydrate (CAS no. 3734-33-6) by using Guideline EEC method 7. Buffers were prepared of pH 4, 7 and 9 then accurately known weight of test chemical were weight and put in 500 mL conical flask and 250 mL appropriate buffers were added. Then samples were taken after 2.4 hrs and 5 days and analyzed by using HPLC. Percent hydrolysis of test chemical N-benzyl-2-[(2,6-dimethylphenyl)amino]-N,N-diethyl-2-oxoethanaminium benzoate hydrate was determined to be less than 10 % at pH 4, 7 and 9 and at temperature 50 oC therefore it is concluded that this test chemical is not hydrolysable.

 

On the basis of results of both the studies it is concluded that test chemical N-benzyl-2-[(2,6-dimethylphenyl)amino]-N,N-diethyl-2-oxoethanaminium benzoate hydrate in not hydrolysable at pH 4, 7 and 9.

Biodegradation:

Biodegradation in water:

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.

  

Biodegradation in water and sediment

Estimation Programs Interface prediction model was run to predict the half-life in water and sediment for the test chemical. If released in to the environment, 3.77% of the chemical will partition into water according to the Mackay fugacity model level III and the half-life period of test chemical in water is estimated to be 60 days (1440 hrs). The half-life (60 days estimated by EPI suite) indicates that the chemical is persistent in water and the exposure risk to aquatic animals is moderate to high whereas the half-life period of test chemical in sediment is estimated to be 541.66 days (13000 hrs). Based on this half-life value, it indicates that test chemical is persistent in sediment.

Biodegradation in soil

In study of biodegradation of soil of Denatonium benzoate (BITREX) was observed in 4 types of soil namely 1.Kitleyknowe,2. Easter Howgate, 3. Boghall, 4. Balmanno for 30days.Recovery of radioactivity in three of the four soils was more than 80% of the applied radioactivity and was recovered in the top 31.5cm of soil However in the Balmanno soil recovery was much lower ca 60%.

Therefore it is considered that in the study conducted for 30 days at 15ºC no significant degradation of the active substance occurred.

Transport and distribution:

Adsorption / desorption

Different experimental data studies have been conducted for adsorption endpoint for test chemical Denatonium benzoate in different forms i.e., granular form and powder form and results of all the studies are summarized below.

First experimental study was done by UERL laboratory (2015) in this study the adsorption coefficient Koc in soil and in sewage sludge of Denatonium benzoate (powder) (CAS No. 3734-33-6)was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The reference substances were chosen according to estimated Kocrange of the test substance and generalized calibration graph was prepared. The reference substances used were 4 chloroaniline, 4 methylaniline, N methylaniline, 2 Nitrophenol, Nitrobenzene, 4-Nitrobenzamide, N,N-dimethylbenzamide, N-methylbenzamide, Benzamide, phenanthrene having Koc value ranging from 1.239 to 4.09. The Log Kocvalue was determined to be 3.392± 0.007at 25°C. On the basis of log Koc value it is concluded that test chemical Denatonium benzoate has strong sorption to soil and sediment and therefore has negligible migration potential to ground water.

Another experimental study was also conducted by UERL lab (2015) in this study the adsorption coefficient Koc in soil and in sewage sludge of Denatonium benzoate (Granules) (CAS No. 3734-33-6) was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The reference substances were chosen according to estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were 4 chloroaniline, 4 methylaniline, N methylaniline, 2 Nitrophenol, Nitrobenzene, 4-Nitrobenzamide, N,N-dimethylbenzamide, N-methylbenzamide, Benzamide, phenanthrene having Kocvalue ranging from 1.239 to 4.09. The Log Koc value was determined to be 3.551± 0.071at 25°C. On the basis of log Koc value it is concluded that test chemical Denatonium benzoate has strong sorption to soil and sediment and therefore has negligible migration potential to ground water.

Last study was experimental study ( from European Draft Assessment Report, 2008) in this report the leaching behaviour of denatonium benzoate was assessed using the column leaching method in four different soil types. In three of the soils less than 0.05% of Denatonium benzoate (BITREX) appeared in the leachate. This indicates a strong adsorption of BITREX to those soils. However in the Boghall soil about 10% AR appeared in the leachate.It should be noted that due to the high amount of organic matter present in theBoghallsoil and its repellent properties to water the soil column was incompletely watering.In conclusion, denatonium benzoate has a high affinity to soil and has negligible potential for leaching.

On the basis of results of all above mentioned studies it is concluded that the test chemical Denatonium benzoate (CAS 3734 -33 -6) has a strong sorption to soil and sediment and therefore has negligible migration potential to groundwater.