Denatonium benzoate

Biodegradation in soil

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in soil

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: Data is from European Draft Assessment Report

Justification for type of information:

Data is from European Draft Assessment Report

Qualifier:

according to guideline

Guideline:

other: as mentioned below

Principles of method if other than guideline:

The study was conducted according to US EPA Pesticide Assessment Guideline, Subdivision N, Environmental Fate: Chemistry, 163-1 (October, 1982).

GLP compliance:

not specified

Test type:

laboratory

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

Radiolabelling:

yes

Oxygen conditions:

aerobic

Soil classification:

not specified

Soil no.:

#1

Soil type:

sandy loam

% Clay:

13.2

% Silt:

31.6

% Sand:

55.2

pH:

6.3

Soil no.:

#2

Soil type:

sand

% Clay:

5.5

% Silt:

8

% Sand:

86.4

pH:

4.9

Soil no.:

#3

Soil type:

sandy loam

% Clay:

16.3

% Silt:

20.2

% Sand:

63.5

pH:

4.5

Soil no.:

#4

Soil type:

silty clay loam

% Clay:

29.2

% Silt:

60.5

% Sand:

10.3

pH:

7

Details on soil characteristics:

SOIL COLLECTION AND STORAGE
- Geographic location:
Soil no:
1. Kitleyknowe
2. Easter Howgate
3. Boghall
4. Balmanno
- Soil preparation (e.g., 2 mm sieved; air dried etc.): Air dried and sieved to less than 5 mm aggregates.
- PROPERTIES OF THE SOILS (in addition to defined fields)
- Moisture content:
Kitleyknowe (Soil 1) Easter Howgate (Soil 2) Boghall (Soil 3) Balmanno (Soil 4)
- 5kPa : 43.1 - 5kPa : 16.3 - 5kPa : 41.9 - 5kPa : 45.8
-33kPa: 33.3 - 33kPa: 16.1 - 33kPa: 36.3 - 33kPa: 33.7

Soil No.:

#1

Duration:

30 d

Soil No.:

#2

Duration:

30 d

Soil No.:

#3

Duration:

30 d

Soil No.:

#4

Duration:

30 d

Soil No.:

#1

Initial conc.:

4.49 other: mg/g soil

Based on:

act. ingr.

Soil No.:

#2

Initial conc.:

5.15 other: mg/g soil

Based on:

act. ingr.

Soil No.:

#3

Initial conc.:

3.73 other: mg/g soil

Based on:

act. ingr.

Soil No.:

#4

Initial conc.:

4.73 other: mg/g soil

Based on:

act. ingr.

Parameter followed for biodegradation estimation:

radiochem. meas.

Details on experimental conditions:

Soils were brought to a soil moisture content giving a matric tension of -33kPa by addition of water and BITREX solution.

Soil No.:

#1

% Degr.:

< 20

Parameter:

radiochem. meas.

Sampling time:

30 d

Remarks on result:

other: Other details not known

Soil No.:

#2

% Degr.:

< 20

Parameter:

radiochem. meas.

Sampling time:

30 d

Remarks on result:

other: Other details not known

Soil No.:

#3

% Degr.:

ca. 60

Parameter:

radiochem. meas.

Sampling time:

30 d

Remarks on result:

other: Other details not known

Soil No.:

#4

% Degr.:

< 20

Parameter:

radiochem. meas.

Sampling time:

30 d

Remarks on result:

other: Other details not known

Transformation products:

not specified

Evaporation of parent compound:

not specified

Volatile metabolites:

not specified

Residues:

not specified

Details on results:

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%.

Summary of the recovery of BITREX in the soil columns

Test soil	Bitrex applied (mg/g soil)	Total recovery (% AR)	Recovery in leachate (% AR)
Kitleyknowe Easter	5.15	92.1	0.045
Howgate	4.49	82.8	0.046
Boghall	3.73	96.3	10.5
Balmanno	4.73	59.5	0.035

 

Recovery of radioactivity in three of the four soils was more than 80% of the applied radioactivity (AR) and was recovered in the top 31.5cm of soil. However in the Balmanno soil recovery was much lower ca 60%.

In three of the soils less than 0.05% of BITREX appeared in the leachate after application of Bitrex. This indicates a strong adsorption of BITREX to those soils. However in the Boghall soil about 10% AR appeared in the leachate.

Conclusions:

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

Executive summary:

In study of biodegradation in 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(AR) 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 in the soil.

Description of key information

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

Additional information

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.