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Adsorption / desorption

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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2018-02-13 to 2018-05-09
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)
Deviations:
no
Qualifier:
according to
Guideline:
other: Council Regulation (EC) No. 440/2008, Method C.18 (2008)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
batch equilibrium method
Media:
soil
Radiolabelling:
no
Test temperature:
Nominal: 20 ± 2 °C
Analytical monitoring:
yes
Details on sampling:
Test Procedure

The study was performed in accordance to OECD-Guideline for Testing of Chemicals No. 106 (2000) and Council Regulation (EC) No. 440/2008, C.18 (2008).

Test vessels 50 mL disposable centrifugation tubes

Concentration for adsorption / desorption experiments
100 mg test item /L (concentration used for adsorption kinetics)
50 mg test item /L
10 mg test item /L
5 mg test item /L
1 mg test item /L

Stock solutions
Stock solutions 100 g/L, 50 g/L, 10g/L, 5g/L and 1g/L of the test item in ultrapure water were prepared. 0.1 volume-% (0.04 mL) of these stock solution, related to the volume of the aqueous phase in the soil suspensions, were used for spiking.

Preparation of the soil samples (conditioning)
The soils were weighed into the test vessels and an appropriate volume of 0.01 M CaCl2-solution was added. After agitation overnight (12 h minimum), the samples were used for adsorption experiments.

Preparation of the samples for adsorption experiments
The soil samples were conditioned as described above. 0.1 volume-% of the stock solutions, related to the volume of the aqueous phase in the soil suspensions was added in order to adjust the test concentrations. Afterwards, the samples were agitated.

Preparation of the samples for desorption experiments
Samples at adsorption equilibrium were used for this purpose. After completion of the adsorption experiments the test vessels were centrifuged, weighed and the supernatant was replaced by fresh 0.01 M CaCl2-solution. Then the test vessels were agitated again to investigate the desorption behavior of the test item.

Samples for analysis
The soil suspensions were centrifuged after agitation at ≥ 4000 rpm (3345 g) to separate the phases, followed by analysing the concentration of the analytes in aqueous phase by LC-MS/MS. For analysis of the soil, the aqueous phase was decanted and the soil was extracted. During Tier 3 adsorption isotherms, test vessels were extracted / rinsed with acetonitrile / 0.01 M CaCl2-solution 50/50 containing 1 % formic acid to determine test vessel adsorption. Extracts were also analysed by LC-MS/MS. . For details see below.

Replicates
All samples were prepared in duplicate.

CONTROLS
CaCl2-solution was conditioned as described above, followed by separation of the aqueous phase by centrifugation. Then the aqueous phase was fortified acc. to the concentrations used for the test item samples to verify the stability of the test item in the aqueous phase under test conditions. The samples were agitated as long as the test item sample with the longest agitation period.

Replicates
Duplicates

BLANK:
Blank samples were prepared for all soils as described for the test item samples but without fortification with the test item. The samples were agitated as long as the samples with the longest agitation period.

Replicates:
Duplicates (Tier 1), single (Tier 2 and Tier 3)

Sample Preparation

Dilution medium:
Acetonitrile : conditioned 0.01 M CaCl2 per soil 50:50 containing 1 % formic acid (matrix calibration for aqueous phase)
Blank extract per soil (acetonitrile : 0.01 M CaCl2 50:50 containing 1 % formic acid) (matrix calibration for soil extraction)

Standards:
A stock solution of 1 g test item/L in 50 mL acetonitrile: ultrapure water (50:50) containing 1 % formic acid was prepared. The solution was diluted to 7 calibration standards in the range of 50 to 1000 µg/L with dilution medium. Matrix calibrations were used.

Aqueous phase:
All samples were centrifuged at 4000 rpm (3445 g). An aliquot of each aqueous sample was stabilized by dilution with acetonitrile containing 2 % formic acis (factor 2). Samples were diluted to calibration range with dilution medium, if necessary.

Soil extraction:
25 mL acetonitrile: 0.01 M CaCl2 (50:50) containing 1 % formic acid were added to the wet soil. Ultrasound was used for 10 min and the vessel was shaken for 60 min. The suspensions were centrifuged at 4000 rpm for 5 min. The extraction was repeated twice with 25 mL acetonitrile: 0.01 M CaCl2 (50:50) containing 1 % formic acid without using ultrasound (3rd extraction step with shaking overnight). The extracts were transferred quantitatively into a 100 mL measuring flask and filled up with acetonitrile: 0.01 M CaCl2 (50:50) containing 1 % formic acid. Blank extract was used for dilutions to calibration range, if necessary.

Samples for method validation:
Samples were prepared as described above (‘soil samples (conditioning)’) with a soil / solution ratio 1:10. The aqueous phases were decanted and spiked with test item at 1 x LOQ level (150 µg/L). All samples were diluted with acetonitrile containing 2 % formic acid by factor 2.

Matrix no.:
#1
Matrix type:
other: silty sand
% Clay:
4.1
% Silt:
10.5
% Sand:
85.4
% Org. carbon:
0.718
pH:
5.9
CEC:
2.4 other: mval/100 g
Matrix no.:
#2
Matrix type:
loamy sand
% Clay:
8.5
% Silt:
11.3
% Sand:
80.2
% Org. carbon:
1.47
pH:
6.6
CEC:
7.6 other: mval/100 g
Matrix no.:
#3
Matrix type:
other: silty sand
% Clay:
8.6
% Silt:
29.3
% Sand:
62.1
% Org. carbon:
0.412
pH:
6.7
CEC:
4.9 other: mval/100 g
Matrix no.:
#4
Matrix type:
clay loam
% Clay:
25.2
% Silt:
42.3
% Sand:
32.6
% Org. carbon:
1.74
pH:
7.5
CEC:
22 other: mval/100 g
Matrix no.:
#5
Matrix type:
loamy sand
% Clay:
10.2
% Silt:
31.1
% Sand:
58.7
% Org. carbon:
0.916
pH:
7.5
CEC:
10 other: mval/100 g
Details on matrix:
Reason for the selection
The content of organic carbon of the selected soils differ significantly. These matrices are suitable for the conduction of the study because all parameters with impact on the adsorption / desorption behavior of a chemical substance were considered.

Origin of soils:
Landwirtschaftliche Untersuchungs- und Forschungsanstalt LUFA Speyer, Obere Langgasse 40, 67346 Speyer, Germany

Storage at test facility:
Room temperature, in closed containers

Details on test conditions:
CaCl2-solution:
Ultrapure water was used to prepare the CaCl2-solution (0.01 M).

Soil / Solution ratio:
Tier 1: 1:40 for soils LUFA 2.2 and LUFA 2.4
1:10 for soils LUFA 2.2, LUFA 2.3 and LUFA 5M
1:5 for soil LUFA 2.1
Tier 2 and tier 3:
1:40 for soil LUFA 2.4
1:10 for soils LUFA 2.2 and LUFA 5M
1:5 for soils LUFA 2.1 and LUFA 2.3

Agitation:
By horizontal shaker. Frequency was adjusted to avoid sedimentation of soil particles during treatment.

Test temperature:
The temperature was in the range of 20 ± 2 °C during the course of the study.
Key result
Sample No.:
#1
Type:
Kd
Value:
4.65 L/kg
pH:
5.9
Temp.:
20 °C
Matrix:
LUFA 2.1 soil/solution ratio 1:5
% Org. carbon:
0.718
Remarks on result:
other: Dodecylpropylenediamine tripropionate
Key result
Sample No.:
#1
Type:
Koc
Value:
648 L/kg
pH:
5.9
Temp.:
20 °C
Matrix:
LUFA 2.1 soil/solution ratio 1:5
% Org. carbon:
0.718
Remarks on result:
other: Dodecylpropylenediamine tripropionate
Key result
Sample No.:
#2
Type:
Kd
Value:
4.25 L/kg
pH:
6.6
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:10
% Org. carbon:
1.47
Remarks on result:
other: Dodecylpropylenediamine tripropionate
Key result
Sample No.:
#2
Type:
Koc
Value:
289 L/kg
pH:
6.6
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:10
% Org. carbon:
1.47
Remarks on result:
other: Dodecylpropylenediamine tripropionate
Key result
Sample No.:
#3
Type:
Kd
Value:
2.02 L/kg
pH:
6.7
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: Dodecylpropylenediamine tripropionate
Key result
Sample No.:
#3
Type:
Koc
Value:
491 L/kg
pH:
6.7
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: Dodecylpropylenediamine tripropionate
Key result
Sample No.:
#4
Type:
Kd
Value:
20.8 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:40
% Org. carbon:
1.74
Remarks on result:
other: Dodecylpropylenediamine tripropionate
Key result
Sample No.:
#4
Type:
log Koc
Value:
1 198 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:40
% Org. carbon:
1.74
Remarks on result:
other: Dodecylpropylenediamine tripropionate
Key result
Sample No.:
#5
Type:
Kd
Value:
8.45 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 5M soil/solution ratio 1:10
% Org. carbon:
0.916
Remarks on result:
other: Dodecylpropylenediamine tripropionate
Key result
Sample No.:
#5
Type:
Koc
Value:
922 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 5M soil/solution ratio 1:10
% Org. carbon:
0.916
Remarks on result:
other: Dodecylpropylenediamine tripropionate
Key result
Sample No.:
#1
Type:
Kd
Value:
25 L/kg
pH:
5.9
Temp.:
20 °C
Matrix:
LUFA 2.1 soil/solution ratio 1:5
% Org. carbon:
0.718
Remarks on result:
other: Tetradecylpropylenediamine tripropionate
Key result
Sample No.:
#1
Type:
Koc
Value:
3 485 L/kg
pH:
5.9
Temp.:
20 °C
Matrix:
LUFA 2.1 soil/solution ratio 1:5
% Org. carbon:
0.718
Remarks on result:
other: Tetradecylpropylenediamine tripropionate
Key result
Sample No.:
#2
Type:
Kd
Value:
24.2 L/kg
pH:
6.6
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:10
% Org. carbon:
1.47
Remarks on result:
other: Tetradecylpropylenediamine tripropionate
Key result
Sample No.:
#2
Type:
Koc
Value:
1 649 L/kg
pH:
6.6
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:10
% Org. carbon:
1.47
Remarks on result:
other: Tetradecylpropylenediamine tripropionate
Key result
Sample No.:
#3
Type:
Kd
Value:
10.9 L/kg
pH:
6.7
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: Tetradecylpropylenediamine tripropionate
Key result
Sample No.:
#3
Type:
Koc
Value:
2 657 L/kg
pH:
6.7
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: Tetradecylpropylenediamine tripropionate
Key result
Sample No.:
#4
Type:
Kd
Value:
114 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:40
% Org. carbon:
1.74
Remarks on result:
other: Tetradecylpropylenediamine tripropionate
Key result
Sample No.:
#4
Type:
Koc
Value:
6 536 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:40
% Org. carbon:
1.74
Remarks on result:
other: Tetradecylpropylenediamine tripropionate
Key result
Sample No.:
#5
Type:
Kd
Value:
53 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 5M soil/solution ratio 1:10
% Org. carbon:
0.916
Remarks on result:
other: Tetradecylpropylenediamine tripropionate
Key result
Sample No.:
#5
Type:
Koc
Value:
5 791 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 5M soil/solution ratio 1:10
% Org. carbon:
0.916
Remarks on result:
other: Tetradecylpropylenediamine tripropionate

Tier 1–Adsorption

 

Tier 1:LUFA 2.1 – Soil / Solution Ratio 1:5

Soil / Solution Ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Adsorption
C12 Compound [%]

Adsorption
C14 Compound [%]

1:40

100

24

50

82

 

Tier 1:LUFA 2.2 – Soil / Solution Ratios 1:10 and 1:40

Soil / Solution Ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Adsorption
C12 Compound [%]

Adsorption
C14 Compound [%]

1:10

100

24

43

79

1:40

100

24

12

35

 

Tier 1:LUFA 2.3 – Soil / Solution Ratio 1:10

Soil / Solution Ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Adsorption
C12 Compound [%]

Adsorption
C14 Compound [%]

1:10

100

24

24

65


 

Tier 1:LUFA 2.4 – Soil / Solution Ratio 1:40

Soil / Solution Ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Adsorption
C12 Compound [%]

Adsorption
C14 Compound [%]

1:40

100

24

37

73

 

  Tier 1:LUFA 5M – Soil / Solution Ratio 1:10

Soil / Solution Ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Adsorption
C12 Compound [%]

Adsorption
C14 Compound [%]

1:10

100

24

54

84

 

Tier 1 – Test Vessel Adsorption

 

Tier 1:LUFA 2.2 – Test Vessel Adsorption – Test Item Control Samples

0.01 M CaCl2 was conditioned with LUFA 2.2

Soil / Solution Ratio

Applied concentration test item [mg/L]

Sampling point [h]

Recovery
C12 Compound [%]

Recovery of
initial C12 Compound [%]

Recovery
C14 Compound [%]

Recovery of
initial C14 Compound [%]

1:40 pp

100

24

90

97

90

100

1:40 gl

100

24

87

93

89

94

 

Table15:      Tier 1:LUFA 2.4 – Test Vessel Adsorption – Test Item Control Samples

0.01 M CaCl2 was conditioned with LUFA 2.4

Soil / Solution Ratio

Applied concentration test item [mg/L]

Sampling point [h]

Recovery
C12 Compound [%]

Recovery of
initial C12 Compound [%]

Recovery
C14 Compound [%]

Recovery of
initial C14 Compound [%]

1:40 pp

100

24

92

108

96

109

1:40 gl

100

24

99

116

102

107

pp                    = 50 mL polypropylene centrifugation tube as test vessel

gl                     = 50 mL disposable glass bottle as test vessel

Tier 1 – Extraction from Soil / Mass Balance

 

Tier 1:Mass Balance LUFA 2.1 Soil / Solution Ratio 1:5
applied test item concentration: 100 mg/L, n=2

 

Sampling point


[h]

Recovery rate from aqueous phase
[%]

Recovery rate from solid phase
[%]

Mass balance1)

[%]

C12 Compound

24 I

54

38

91

24 II

45

44

C14 Compound

24 I

19

78

97

24 II

17

80

I, II                   = replicate number

1)                     =Sum of aqueous phase and solid phase, mean value

 

Tier 1:Mass Balance LUFA 2.2 Soil / Solution Ratio 1:10
applied test item concentration: 100 mg/L, n=2

 

Sampling point


[h]

Recovery rate from aqueous phase
[%]

Recovery rate from solid phase
[%]

Mass balance1)

[%]

C12 Compound

24 I

60

27

85

24 II

57

26

C14 Compound

24 I

25

62

84

24 II

21

60

I, II                   = replicate number

1)                     = Sum of aqueous phase and solid phase, mean value


 

Tier 1:Mass Balance LUFA 2.3 Soil / Solution Ratio 1:10
applied test item concentration: 100 mg/L, n=2

 

Sampling point


[h]

Recovery rate from aqueous phase
[%]

Recovery rate from solid phase
[%]

Mass balance1)

[%]

C12 Compound

24 I

77

20

95

24 II

74

20

C14 Compound

24 I

37

55

89

24 II

34

53

I, II                   = replicate number

1)                     = Sum of aqueous phase and solid phase, mean value

 

Tier 1:Mass Balance LUFA 2.4 Soil / Solution Ratio 1:40
applied test item concentration: 100 mg/L, n=2

 

Sampling point


[h]

Recovery rate from aqueous phase
[%]

Recovery rate from solid phase
[%]

Mass balance1)

[%]

C12 Compound

24 I

56

29

89

24 II

63

30

C14 Compound

24 I

23

67

91

24 II

25

67

I, II                   = replicate number

1)                     = Sum of aqueous phase and solid phase, mean value

 

Tier 1:Mass Balance LUFA 5M Soil / Solution Ratio 1:10
applied test item concentration: 100 mg/L, n=2

 

Sampling point


[h]

Recovery rate from aqueous phase
[%]

Recovery rate from solid phase
[%]

Mass balance1)

[%]

C12 Compound

24 I

47

44

87

24 II

45

38

C14 Compound

24 I

18

76

88

24 II

14

67

I, II                   = replicate number

1)                     = Sum of aqueous phase and solid phase, mean value

 


 

 Tier 2 – Adsorption Kinetics

 

Equilibrium Time, Measured Amounts in Aqueous Phase and Soil Extracts, Percent of Adsorption and Distribution Coefficients Kd, KOC for C12 Compound

Applied concentration, test item:          100 mg/L

Applied amount, test item:                     4 mg

Applied amount, a.i.:                         763 µg

time to reach equilibrium                      24 h

n = 2; Vaq= 40 mL

Soil Type

s/s ratio

msoil

 [g]

madsaq(eq)

[µg]

madss(eq)

[µg]

Kd

[mL/g]

%OC

KOC[mL/g]

Adsorption [%]

LUFA 2.1

1:5

7.75

374

337

4.65

0.718

648

51

LUFA 2.2

1:10

3.71

453

179

4.25

1.47

289

41

LUFA 2.3

1:5

7.69

520

202

2.02

0.412

491

32

LUFA 2.4

1:40

0.906

431

204

20.8

1.74

1198

44

LUFA 5M

1:10

3.70

412

321

8.45

0.916

922

46

Vaq            =used volume of aqueous phase

s/s ratio    =soil / solution ratio

msoil           =used amount of soil (dry weight)

madsaq        =amount of a.i. in the aqueous phase at equilibrium

madss          =amount of a.i. in the soil at equilibrium

%OC         =percentage of organic carbon content in the soil


 

Equilibrium Time, Measured Amounts in Aqueous Phase and Soil Extracts, Percent of Adsorption and Distribution CoefficientsKd,KOCfor C14 Compound

Applied concentration, test item:          100 mg/L

Applied amount, test item:                     4 mg

Applied amount, a.i.: 191 µg

time to reach equilibrium                      24 h

n = 2; Vaq= 40 mL

Soil Type

s/s ratio

msoil

 [g]

madsaq(eq)

[µg]

madss(eq)

[µg]

Kd

[mL/g]

%OC

KOC[mL/g]

Adsorption [%]

LUFA 2.1

1:5

7.75

28.8

140

25.0

0.718

3485

85

LUFA 2.2

1:10

3.71

44.1

99.2

24.2

1.47

1649

77

LUFA 2.3

1:5

7.69

53.0

112

10.9

0.412

2657

72

LUFA 2.4

1:40

0.906

44.9

116

114

1.74

6536

76

LUFA 5M

1:10

3.70

29.0

142

53.0

0.916

5791

85

Vaq            =used volume of aqueous phase

s/s ratio    =soil / solution ratio

msoil           =used amount of soil (dry weight)

madsaq        =amount of a.i. in the aqueous phase at equilibrium

madss          =amount of a.i. in the soil at equilibrium

%OC         =percentage of organic carbon content in the soil

 

Tier 3 – Desorption Kinetics

The desorption behavior of the test item was determined after 24 h adsorption.

 

Percent of Desorption and Desorption Coefficient Kdes for C12 Compound

Applied concentration, test item:          100 mg/L

Applied amount, test item:                     4 mg

Applied amount, a.i.: 764 µg

n = 2; Vaq= 100 mL

Soil Type

s/s ratio

teq[h]

msoil[g]

mdesaq(eq) [µg]

madss(eq) [µg]

Kdes[mL/g]

Desorption [%]

LUFA 2.1

1:5

24

7.75

98.5

472

19.6

21

LUFA 2.2

1:10

24

3.71

96.9

248

16.8

39

LUFA 2.3

1:5

24

7.69

121

277

6.69

44

LUFA 2.4

1:40

24

0.906

165

219

14.6

78

LUFA 5M

1:10

24

3.70

162

341

11.9

48

 

Percent of Desorption and Desorption Coefficient Kdes for C14 Compound

Applied concentration, test item:          100 mg/L

Applied amount, test item:                     4 mg

Applied amount, a.i.: 191 µg

n = 2; Vaq= 100 mL

Soil Type

s/s ratio

teq[h]

msoil[g]

mdesaq(eq) [µg]

madss(eq) [µg]

Kdes[mL/g]

Desorption [%]

LUFA 2.1

1:5

24

7.75

11.3

171

73.3

7

LUFA 2.2

1:10

24

3.71

19.2

138

66.7

14

LUFA 2.3

1:5

6

7.69

23.1

147

28.0

12

LUFA 2.4

1:40

24

0.906

36.1

140

127

26

LUFA 5M

1:10

24

3.70

21.9

161

68.9

14

Vaq            =used volume of aqueous phase

s/s ratio    =soil / solution ratio

teq              =time to reach equilibrium based on figures 10 to 12

msoil          =used amount of soil (dry weight)

mdesaq        =amount a.i. measured in the aqueous phase after desorption step

(entrained water taken into account)

madss          =amount of a.i. adsorbed to soil at equilibrium


Tier 3 – Adsorptions Isotherms

 

Freundlich AdsorptionIsotherms for C12 Compound

Applied test item concentrations:        1, 5, 10, 50, 100 mg/L

Agitation                                    24 h

Volume of aqueous phase:              40 mL

Soil Type

msoil[g]

r2

1/n

KFads

KFOC

Kd[ml/g]*

KOC[ml/g]*

LUFA 2.1

7.75

0.978

0.68

9.66

1345

28.2

3925

LUFA 2.2

3.71

0.993

0.73

7.91

538

32.8

2231

LUFA 2.3

7.69

0.987

0.90

2.78

675

4.84

1175

LUFA 2.4

0.906

0.985

0.96

14.3

822

34.4

1975

LUFA 5M

3.70

0.992

1.0

8.57

935

3.23

352

 

Freundlich Adsorption Isotherms for C14 Compound

Applied test item concentrations:        1, 5, 10, 50, 100 mg/L

Agitation                                   24 h

Volume of aqueous phase:              40 mL

Soil Type

msoil[g]

r2

1/n

KFads

KFOC

Kd[ml/g]*

KOC[ml/g]*

LUFA 2.1

7.75

0.996

0.76

23.0

3199

32.2

4480

LUFA 2.2

3.71

0.996

0.78

24.4

1661

15.5

1052

LUFA 2.3

7.69

0.991

0.91

14.0

3402

0.470

114

LUFA 2.4

0.906

0.982

0.93

75.6

4346

113

6484

LUFA 5M

3.70

0.994

1.0

41.8

4564

5.11

558

msoil    = used amount of soil (dry weight) [g]

n         = regression constant

%OC   = percentage of organic carbon content in the soil

KFads    = Freundlich adsorption coefficient [µg1-1/n(mL)1/ng-1]

KFOC     = Freundlich adsorption coefficient normalized to content of organic carbon [µg1-1/n(mL)1/ng-1]

*)               = for test item concentration 1 mg/L


 


 

Tier 3– Desorption Isotherms

In some samples, results < LOQ were measured. Hence the Freundlich desorption coefficient KFdes were not determined because the linearity of the desorption isotherms was not given. Therefore, individual values of Kdes and mean values have been calculated. Samples < LOQ were not considered. The tables below summarize the results.

Freundlich Desorption Isotherms for C12 compound

Adsorption                                                  24h

Desorption 24h

m soil (dry weight) [g]                                      7.75            LUFA 2.1

                                                                3.71            LUFA 2.2

                                                                7.69            LUFA 2.3

                                                                0.906          LUFA 2.4

                                                                3.70            LUFA 5M

Volume of aqueous phase:                               40 mL

Soil Type

Ctest item[mg/L]

ma.i.[µg]

madsaq(eq)

[µg]

madss(eq)

[µg]

Kdes[ml/g]

Kdes

mean value[ml/g]

LUFA 2.1

100

763

85.3

206

12.4

27.8

50

382

39.4

150

19.7

10

76.3

5.04

39.8

40.8

5

38.2

2.65

19.7

38.4

LUFA 2.2

100

763

52.8

120

24.5

50.4

50

382

27.7

66.8

26.0

10

76.3

2.40

22.4

101

LUFA 2.3

100

763

87.9

106

6.29

8.49

50

382

58.8

47.3

4.19

10

76.3

5.18

14.9

15.0

LUFA 2.4

100

763

134

42.7

14.0

83.0

50

382

68.7

9.78

6.28

10

76.3

11.7

4.51

17.1

5

38.2

0.947

6.32

295

LUFA 5M

100

763

118

147

13.5

35.6

50

382

53.1

102

20.9

10

76.3

3.13

20.9

72.3

c test item      = applied concentration of the test item

ma.i.          = applied amount of the a.i.

madsaq        =amount of a.i. in the aqueous phase at equilibrium

madss          =amount of a.i. in the soil at equilibrium

Freundlich Desorption Isotherms for C14 compound

Adsorption                                                24h

Desorption 24h

m soil (dry weight) [g]                                      7.75            LUFA 2.1

                                                                3.71            LUFA 2.2

                                                                7.69            LUFA 2.3

                                                                0.906          LUFA 2.4

                                                                3.70            LUFA 5M

Volume of aqueous phase:                               40 mL

Soil Type

Ctest item[mg/L]

ma.i.[µg]

madsaq(eq)

[µg]

madss(eq)

[µg]

Kdes[ml/g]

Kdes

mean value[ml/g]

LUFA 2.1

100

191

10.9

111

52.7

111

50

95.4

4.73

66.4

72.5

10

19.1

0.348

14.0

207

5

9.54

0.212

6.75

164

LUFA 2.2

100

191

12.6

85.5

73.1

84.2

50

95.4

5.03

44.4

95.3

LUFA 2.3

100

191

16.1

97.9

31.6

58.0

50

95.4

8.61

50.8

30.7

10

19.1

0.418

8.98

112

LUFA 2.4

100

191

35.0

67.6

85.4

128

50

95.4

14.9

33.4

99.0

10

19.1

1.63

7.34

199

LUFA 5M

100

191

15.7

97.4

67.2

261

50

95.4

5.80

61.2

114

10

19.1

0.163

9.06

601

c test item= applied concentration of the test item

ma.i.          = applied amount of the a.i.

madsaq        =amount of a.i. in the aqueous phase at equilibrium

madss          =amount of a.i. in the soil at equilibrium

Validity criteria fulfilled:
yes
Executive summary:

The adsorption / desorption behavior of the test item Sodium cocopropylenediamine propionate(batch no.48724) was investigated in five different soils according to OECD guideline 106 and Council Regulation (EC) No. 440/2008, C.18 from 2018-02-13 to 2017-05-09 at Noack Laboratorien GmbH, 31157 Sarstedt, Germany. Distribution coefficients Kd and organic carbon normalized distribution coefficients KOC were determined with a single concentration. The desorption behavior / reversibility of the adsorption from the soils and the degree of adsorption and desorption as a function of the test item loading level (Freundlich adsorption and desorption isotherms) in the aqueous phase were investigated. Two active ingredients Dodecylpropylenediaminetripropionate and Tetradecylpropylenediaminetripropionate were used as lead components of the test item and were analysed by LC-MS/MS. Data are given for each analyte in this report.

RelevantCharacteristics of Test Matrices

 

Soils

 

LUFA 2.1

LUFA 2.2

LUFA 2.3

LUFA 2.4

LUFA 5M

Soil Type1)

Silty sand

Loamy sand

Silty sand

Clayey loam

Loamy sand

pH (0.01 M CaCl2)3)

4.9

5.4

5.9

7.4

7.3

Organic Carbon [%]2)

0.718

1.47

0.412

1.74

0.916

Clay (<0.002 mm) [%]2)

4.1

8.5

8.6

25.2

10.2

Silt (0.002-0.063 mm) [%]2)

10.5

11.3

29.3

42.3

31.1

Sand (0.063-2 mm) [%]2)

85.4

80.2

62.1

32.6

58.7

Cation Exchange Capacity [mval/100g]2)

2.4

7.6

4.9

22

10

1)according to German DIN

2)determined at Agrolab Agrar und Umwelt GmbH (non-GLP)

3) Analyses data sheet provided by LUFA Speyer

 

Experiments in Tier 1 showed no significant adsorption to the test vessel surfaces. A mass balance between 84 % and 97 % was determined. Mass balances < 90% were assumed to be caused by fast formation of non extractable residues rather than by degradation of the test item in soil. Based on the results of Tier 1 soil / solution ratios of 1:40 for soil LUFA 2.4, 1:10 for soils LUFA 2.2 and LUFA 5M and 1:5 for soils LUFA 2.1 and LUFA 2.3 were used for adsorption experiments with an agitation time of 24h. Experiments for adsorption and desorption kinetics were conducted with a nominal test item concentration of 100 mg test item/L (K1). Desorption kinetic experiments were conducted over 48h. Additional application levels of 50, 10, 5 and 1 mg test item/L (K2 – K5) were used for the determination of Freundlich adsorption and desorption isotherms with an agitation time of 24h each. The agitation time for the desorption isotherms was reduced because a decrease of the test item in the aqueous phase was observed between 24h and 48h. Adsorption kinetic experiments (Tier 2) as well as the desorption experiments in Tier 3 were analysed by the indirect method (only the aqueous phase was analysed). In contrast, the direct method (analysis of samples of the aqueous phase and soil extracts) was used during the determination of the adsorption isotherms because occasionally mass balances were < 90% during experiments in Tier 1.

The table below presents the observed distribution coefficients Kd and their corresponding organic carbon normalized distribution coefficients KOC. Furthermore, the mobility of the test item in the investigated matrices was classified according to McCallet al.(1980) based on the obtained values for the organic carbon normalised Freundlich adsorption coefficient KFOC. Additionally, the desorption coefficient Kdes and KOCF are presented in the summarizing table.

Summarized Endpoints forSodium cocopropylenediamine propionateand the Active Ingredients

Mobility according to McCall et al. (1980): KOC 0 – 50 very high, KOC 50 – 150 high, KOC 150 – 500 medium, KOC 500 – 2000 low, KOC 2000 – 5000 slight, KOC > 5000 immobile

Soil

Soil / Solution Ratio

maq(eq)
[µg]

Kd
[mL/g]

KOC
[mL/g]

Kdes
[mL/g]

KFOC

[µg1-1/n
(mL)1/ng-1]

1/n

Mobility according to McCall et al. based on KFOC

Dodecylpropylenediamine tripropionate

LUFA 2.1

1:5

374

4.65

648

27.8

1345

0.68

low

LUFA 2.2

1:10

453

4.25

289

50.4

538

0.73

low

LUFA 2.3

1:5

520

2.02

491

8.49

675

0.90

low

LUFA 2.4

1:40

431

20.8

1198

83.0

822

0.96

low

LUFA 5M

1:10

412

8.45

922

35.6

935

1.0

low

Tetradecylpropylenediamine tripropionate

LUFA 2.1

1:5

28.8

25.0

3485

111

3199

0.76

slight

LUFA 2.2

1:10

44.1

24.2

1649

84.2

1661

0.78

low

LUFA 2.3

1:5

53.0

10.9

2657

58.0

3402

0.91

slight

LUFA 2.4

1:40

44.9

114

6536

128

4346

0.93

slight

LUFA 5M

1:10

29.0

53.0

5791

261

4564

1.0

slight

Sodium cocopropylenediamine propionate– Weighted Average Value

LUFA 2.1

1:5

305

8.72

1215

44.4

1716

0.70

low

LUFA 2.2

1:10

371

8.24

561

57.2

763

0.74

low

LUFA 2.3

1:5

427

3.80

924

18.4

1220

0.90

low

LUFA 2.4

1:40

354

39.4

2266

92.0

1527

0.95

low

LUFA 5M

1:10

335

17.4

1896

80.7

1661

1.0

low

maq(eq)           = mass in the aqueous phase at adsorption equilibrium; value was calculated for Sodium cocopropylenediamine propionatefrom measured concentrations of the active ingredients and taking the respective contents into account

KOC [mL/g]      = determined for 100 mg test item /L during adsorption kinetics

Kdes                  mean value derived from the desorption isotherms

LUFA 2.1       C12 Compound: K1 – K4   C14 Compound: K1 – K3

LUFA 2.2       C12 Compound: K1 – K3   C14 Compound: K1 – K2

LUFA 2.3       C12 Compound: K1 – K3   C14 Compound: K1 – K3

LUFA 2.4       C12 Compound: K1 – K4   C14 Compound: K1 – K3

LUFA 5M       C12 Compound: K1 – K3   C14 Compound: K1 – K3

 

Only the four highest concentrations were considered for the calculation of the adsorption isotherms because the measured concentrations were at least in one of the analysed matrices (aqueous phase or soil) lower than the lowest calibration level at the end of the experiment.

No desorption isotherms were determined because the desorption was low in the lower application concentrations leading also to values lower than the lowest calibration level in the aqueous phase. Instead a mean value for Kdes was calculated by taking into account these application levels with concentrations inside the calibration range in the aqueous phase at the end of the experiment. 

A weighted average value was calculated for all endpoints. A typical distribution of the lead components of 64% Dodecylpropylenediaminetripropionate and 16 % Tetradecylpropylenediaminetripropionate was considered for this purpose.

The test item Sodium cocopropylenediamine propionate adsorbs to all tested soils with KFoc values between 763 and 1716 and has therefore a low mobility in soils according to McCall et al. The adsorption was not completely reversible because the desorption coefficients Kdes were higher than the adsorption coefficients Kd in all soils and for both components.

Description of key information

The adsorption / desorption behavior of Sodium cocopropylenediamine propionate CAS no. 2136366 -30 -6 was investigated in sorption/desorption test using five different soils according to OECD guideline 106.

The quantification was focused on the two main constituents which are the Sodium dodecylpropylenediamine propionate (64%) and the Sodium tetradecylpropylenediamine propionate (16%). For both constituents the freundlich adsorption and desorption isotherms using 5 different test concentrations were determined for each of the 5 soils. The mean Koc of Sodium dodecylpropylenediamine propionate for the 5 soils was 709.6 L/kg. The mean Koc of Sodium tetradecylpropylenediamine propionate for the 5 soils was 4023.6 L/kg. The weighted mean Koc for the 5 soils taking the two main constituents as representative for Sodium cocopropylenediamine propionate is 1372.4 L/kg. The mean KfOC which is the mean Koc derived from the Freundlich isotherms is 1377.4 L/kg. This last value will be used for risk assessment purposes.

Key value for chemical safety assessment

Koc at 20 °C:
1 377.4

Additional information

The adsorption / desorption behavior ofSodium cocopropylenediamine propionate CAS no. 2136366 -30 -6 was investigated in sorption/desorption test using five different soils according to OECD guideline 106.

The quantification was focused on the two main constituents which are the Sodium dodecylpropylenediamine propionate (64%) and the Sodium tetradecylpropylenediamine propionate (16%). For both constituents the freundlich adsorption and desorption isotherms using 5 different test concentrations were determined for each of the 5 soils. The mean Koc ofSodium dodecylpropylenediamine propionate for the 5 soils was 709.6 L/kg.The mean Koc ofSodium tetradecylpropylenediamine propionate for the 5 soils was 4023.6 L/kg. The weighted mean Koc for the 5 soils taking the two main constituents as representative for Sodium cocopropylenediamine propionate is 1372.4 L/kg. The mean KfOC which is the mean Koc derived from the Freundlich isotherms is 1377.4 L/kg. This last value will be used for risk assessment purposes.

Based on results of preliminary investigations during Tier 1, a soil / solution ratio of 1:40 for soil LUFA 2.4, 1:10 for soils LUFA 2.2 and LUFA 5M and 1:5 for soils LUFA 2.1 and LUFA 2.3

was used for adsorption experiments. Experiments for adsorption and desorption kinetics were conducted with a nominal test item concentration of 100 mg/L. For investigations concerning the Freundlich adsorption and desorption isotherms, additional concentrations of 50 mg/L, 10 mg/L, 5 mg/L and 1 mg/L have been applied. Two active ingredients Dodecylpropylenediaminetripropionate and Tetradecylpropylenediaminetripropionate were used as lead components of the test item and were analysed by LC-MS/MS. Data are given for each analyte in this report.

The table below presents the observed distribution coefficients Kd and their corresponding organic carbon normalized distribution coefficients KOC. Furthermore, the mobility of the test item in the investigated matrices was classified according to McCallet al.(1980). Additionally, the desorption coefficient Kdes and the organic carbon normalized Freundlich adsorption coefficient KOCF are presented in the summarizing table. Since the adsorption for the lower concentrations was higher the measured concentrations for the desorption was lower than the limit of quantification. Hence the Freundlich desorption coefficient KFdes was not determined because the linearity of the desorption isotherms was not given. Therefore individual values of Kdesand mean values have been calculated.

A weighted average value was calculated for all endpoints. A typical distribution of the lead components of 64% Dodecylpropylenediaminetripropionate 16 % Tetradecylpropylenediaminetripropionate was considered for this purpose.

Summarized Endpoints forSodium cocopropylenediamine propionateand the Active Ingredients

Mobility according to McCall et al. (1980): KOC 0 – 50 very high, KOC 50 – 150 high, KOC 150 – 500 medium, KOC 500 – 2000 low, KOC 2000 – 5000 slight, KOC> 5000 immobile

Soil

Soil / Solution Ratio

maq(eq)
[µg]

Kd
[mL/g]

KOC
[mL/g]

Kdes
[mL/g]

KFOC

[µg1-1/n
(mL)1/ng-1]

Mobility according to McCall et al.

Dodecylpropylenediamine tripropionate

LUFA 2.1

1:5

374

4.65

648

27.8

1345

low

LUFA 2.2

1:10

453

4.25

289

50.4

539

medium

LUFA 2.3

1:5

520

2.02

491

9.49

675

medium

LUFA 2.4

1:40

431

20.8

1198

83.0

822

low

LUFA 5M

1:10

412

8.45

922

35.6

935

low

Tetradecylpropylenediamine tripropionate

LUFA 2.1

1:5

28.8

25.0

3485

111

3199

slight

LUFA 2.2

1:10

44.12

24.2

1649

84.2

1661

low

LUFA 2.3

1:5

53.0

10.9

2657

58.0

3402

slight

LUFA 2.4

1:40

44.9

114

6536

128

4346

immobile

LUFA 5M

1:10

29.0

53.0

5791

261

4564

immobile

Sodium cocopropylenediamine propionate– Weighted Average Value

LUFA 2.1

1:5

305

8.72

1215

44.4

1716

low

LUFA 2.2

1:10

371

8.24

561

57.2

763

medium

LUFA 2.3

1:5

427

3.80

924

19.2

1220

low

LUFA 2.4

1:40

354

39.4

2266

92.0

1527

low

LUFA 5M

1:10

335

17.36

1896

80.7

1661

low

maq(eq)           = mass in the aqueous phase at adsorption equilibrium; value was calculated forSodium cocopropylenediamine propionate from measured concentrationsof the active ingredients and taking the respective contents into account

Kdes                  mean value derived from the desorption isotherms

The test item Sodium cocopropylenediamine propionate adsorbs to all tested soils with Koc values between 561 and 2266 and has therefore a low mobility in soils according to McCallet al. The desorption was not completely reversible.