1H-1,2,4-Triazole-1-carboxamide, 4-amino-N-(1,1-dimethylethyl)-4,5-dihydro-3-(1-methylethyl)-5-oxo-

Biodegradation in soil

Administrative data

Endpoint:

biodegradation in soil

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed to modern guidelines and described in sufficient detail.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: EPA 835.4100 (2009)

GLP compliance:

yes

Test type:

laboratory

Test material

Test material information

Constituent 1

Reference substance name:

4-amino-N-tert-butyl-5-oxo-3-(propan-2-yl)-4,5-dihydro-1H-1,2,4-triazole-1-carboxamide

EC Number:

603-373-3

Cas Number:

129909-90-6

Molecular formula:

C10H19N5O2

IUPAC Name:

4-amino-N-tert-butyl-5-oxo-3-(propan-2-yl)-4,5-dihydro-1H-1,2,4-triazole-1-carboxamide

Details on test material:

3.19 MBq/mg

Radiolabelling:

yes

Study design

Oxygen conditions:

aerobic

Soil classification:

USDA (US Department of Agriculture)

Soil properties

Soil properties 1

Soil no.:

#1

Soil type:

clay loam

% Clay:

33

% Silt:

38

% Sand:

29

% Org. C:

ca. 3.1

pH:

6.6

CEC:

23.2 meq/100 g soil d.w.

Bulk density (g/cm³):

0.92

Soil properties 2

Soil no.:

#2

Soil type:

sandy loam

% Clay:

17

% Silt:

13

% Sand:

70

% Org. C:

1.52

pH:

6.8

CEC:

16.2 meq/100 g soil d.w.

Bulk density (g/cm³):

1.05

Soil properties 3

Soil no.:

#3

Soil type:

loamy sand

% Clay:

8

% Silt:

6

% Sand:

86

% Org. C:

1.2

pH:

5.6

CEC:

10.5 meq/100 g soil d.w.

Bulk density (g/cm³):

1.15

Soil properties 4

Soil no.:

#4

Soil type:

loam

% Clay:

17

% Silt:

44

% Sand:

39

% Org. C:

1.3

pH:

7.2

CEC:

12.9 meq/100 g soil d.w.

Bulk density (g/cm³):

0.99

Initial test substance concentration

Initial test substance concentration 1

Soil No.:

#1

Initial conc.:

0.578 - 0.584 ppm

Based on:

test mat.

Initial test substance concentration 2

Soil No.:

#2

Initial conc.:

0.568 - 0.574 ppm

Based on:

test mat.

Initial test substance concentration 3

Soil No.:

#3

Initial conc.:

0.566 - 0.57 ppm

Based on:

test mat.

Initial test substance concentration 4

Soil No.:

#4

Initial conc.:

0.514 - 0.517 ppm

Based on:

test mat.

Experimental conditions

Experimental conditions 1

Soil No.:

#1

Temp.:

20

Humidity:

75% 1/3 bar

Microbial biomass:

73.04 mg C/100g

Experimental conditions 2

Soil No.:

#2

Temp.:

20

Humidity:

75% 1/3bar

Microbial biomass:

50.72 mg C/100g

Experimental conditions 3

Soil No.:

#3

Temp.:

20

Humidity:

75% 1/3bar

Microbial biomass:

7.63 mg C/100g

Experimental conditions 4

Soil No.:

#4

Temp.:

20

Humidity:

75% 1/3 bar

Microbial biomass:

35.50 mg C/100g

Results and discussion

Material (mass) balance

Material (mass) balance 1

Soil No.:

#1

% Recovery:

102.3

St. dev.:

2.4

Material (mass) balance 2

Soil No.:

#2

% Recovery:

101.6

St. dev.:

2.5

Material (mass) balance 3

Soil No.:

#3

% Recovery:

101.4

St. dev.:

2.6

Material (mass) balance 4

Soil No.:

#4

% Recovery:

99.7

St. dev.:

2.4

% Degradation

% Degradation 1

Soil No.:

#1

% Degr.:

10.8

Parameter:

radiochem. meas.

Sampling time:

222 d

% Degradation 2

Soil No.:

#2

% Degr.:

7.8

Parameter:

radiochem. meas.

Sampling time:

222 d

% Degradation 3

Soil No.:

#3

% Degr.:

17.2

Parameter:

radiochem. meas.

Sampling time:

222 d

% Degradation 4

Soil No.:

#4

% Degr.:

ca. 10

Parameter:

radiochem. meas.

Sampling time:

221 d

Half-life / dissipation time of parent compound

Half-life / dissipation time of parent compound 1

Soil No.:

#1

DT50:

70 d

St. dev.:

0.899

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: DT90 233 days

Half-life / dissipation time of parent compound 2

Soil No.:

#2

DT50:

58.2 d

St. dev.:

0.872

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: DT90 194 days

Half-life / dissipation time of parent compound 3

Soil No.:

#3

DT50:

72.2 d

St. dev.:

0.504

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: DT90 240 days

Half-life / dissipation time of parent compound 4

Soil No.:

#4

DT50:

59.2 d

St. dev.:

0.685

Type:

(pseudo-)first order (= half-life)

Remarks on result:

other: DT90 197 days

Transformation products:

yes

Identity of transformation products

Identity of transformation products 1

No.:

#1

Reference

Reference substance name:

Unnamed

IUPAC name:

desamino amicarbazone

Identity of transformation products 2

No.:

#2

Reference

Reference substance name:

Unnamed

IUPAC name:

N-methyl desamino amicarbazone

Identity of transformation products 3

No.:

#3

Reference

Reference substance name:

Unnamed

IUPAC name:

Decarboxamide

Details on transformation products:

#1 (max) 59.4%; #2 (max) 8.6%; #3 (max) 0.2%, D1 (max) 24.1% (loamy sand soil), <2% other soils; D2 (max) 5.6%

Evaporation of parent compound:

yes

Volatile metabolites:

yes

Residues:

yes

Details on results:

Bound Residues reached a maximum of 49.5% then declined to a maximum of 33.8% at 222 days. Max 3.3% volatiles (CO2).

Applicant's summary and conclusion

Conclusions:

A comprehensive degradation study in four soils with a mean DT50 of 64.9 days.

Executive summary:

A well documented study on the route and rate of Amicarbazone in four soils. The DT50s ranged from 58.2 to 72.2 days with a mean of 64.9 days. Amicarbozone degraded to 3 known metabolites; desamino amicarbazone (max. 59.4%), N-methyl desamino amicarbazone (max. 8.6%) and decarboxamide (max. 0.2%). D1 was formed in some of the soils at <2% but had a maximum of 24% in the loamy sand soil. D2 was formed at a maximum of 5.6%.

Bound residues reached a maximum of 33.8% at termination of the study and mineralisation was <5%.

Overall mass balance was 99.7 ± 2.4% to 102.3 ± 2.4% for all samples.