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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:
2017-05-15 to 2017-08-11
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)
Version / remarks:
The number of soils which were used deviates from the guideline recommendation in the guideline as three soils were used instead of the recommended five soils. The Freundlich isotherms were not determined and the adsorption / desorption behavior was investigated based on one test item concentration. These deviations from the guideline were on request of the sponsor.

Samples were centrifuged < 3000 g if glass vessels had to be used. Higher centrifugation forces would have been
destructive to these vials.
The indirect method was used for the anionic and the cationic component, although the mass balance was partly < 90%. The test item was not completely extractable from aged soil samples.

Deviations:
yes
Remarks:
see above at "Version / remarks"
Qualifier:
according to
Guideline:
other: Council Regulation (EC) No. 440/2008, Method C.18 (2008)
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:

Test vessels:
50 mL disposable centrifugation tubes or 120 mL disposable glass bottles

Concentration for adsorption / desorption:
Due to different adsorption behavior and with regard to the respective limits of quantification, Tier 2 was performed experiments at two concentrations:
For C10-, C11- and C12- alkylbenzene sulfonic acid: 5.0 mg/L
For N,N-dimethyl-1,3-propanediamine: 6.0 mg/L

Stock solutions:
Stock solutions of 10 g/L ACAR16015 in 25 mL methanol were prepared. 0.1 volume-% of these stock solutions, related to the volume of the aqueous phase inthe soil suspensions, was 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:
The soil samples were conditioned as described above. 0.1 volume-% of the stock solutions, related to the volume of the experiments aqueous phase in the soil suspensions was added in order to obtain the required test concentrations. Afterwards, the samples were agitated.

Preparation of the samples for desorption experiments:
Test vessels from the adsorption experiments were used for this purpose. After completion of the adsorption experiments the test vessels were centrifuged, weighed and the supernatant was replaced by fresh CaCl2 solution. Then the test vessels were agitated again to investigate the desorption behavior of the test item.


Preparation of samples:
The soil suspensions in disposable glass bottles (soil / solution ratio for analysis 1:100) were centrifuged at 3000 rpm (2504 g) and the soil suspensions in centrifugation tubes (soil / solution ratios 1:5 and 1:30) at 4000 rpm (3345 g) after agitation to separate the phases, followed by analysing the concentration of the main components of Benzenesulfonic acid, C10-13-alkyl derivs., compds with N,N-dimethyl-1, 3-propanediamine in the aqueous phase by LC-MS/MS. For analysis of the soil, the aqueous phase was decanted and the soil was extracted. Extracts were also analysed by LC-MS/MS.

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 according 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 longas the samples with the longest agitation period.

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


Sample Preparation:

Dilution medium:
Methanol / matrix-conditioned CaCl2 solution (0.01 M) (50:50) containing 0.1% formic acid

Standards:
Stock solutions of 10 g/L of the test item in methanol were prepared and were diluted to calibration standards.
At least 6 calibration standards in the range of 100 to 1000 µg/L were prepared using dilution medium for the quantification of C10-C13 alkylbenzene sulfonic acid.
At least 6 calibration standards in the range of 20 to 500 µg/L were prepared using dilution medium for the quantification of N,N-dimethyl-1,3-propanediamine.

Aqueous phase:
Samples in glass bottles were centrifuged at 3000 rpm (2504 g) for 5 min. Samples in centrifugation tubes were centrifuged at 4000 rpm (3345 g) for 5 min. An aliquot of each aqueous sample was stabilised by dilution with methanol containing 0.2% formic acid (factor 2). Samples were diluted to calibration range with dilution medium, if necessary.

Test vessel extraction:
The test vessels were extracted after removal of the soil by adding 5 mL dilution medium and shaking the test vessels for 10 min. Extracts were measured after filtration using disposable syringe filter.

Soil extraction - ASE:
The soil was extracted by using an accelerated solvent extractor (ASE) for investigation of the sorbed anionic and cationic component. After decantation of the aqueous phase, the soil was used for extraction. Each sample was extracted after addition of 2 g magnesium chloride hexahydrate and 4 g silica gel with 2-propanol : HPLC water (50 : 50). For parameters of the extraction method see below. Extracts were transferred quantitatively into a 100 mL measuring flask and filled up with
2-propanol : HPLC water (50 : 50). Aliquots were diluted with the extract of a blank sample to calibration range.

Parameters of the ASE method:
Preheat: 1 min
Heat: 6 min
Static: 10 min
Flush: 50 % (v/v)
Purge: 90 sec
Cycles: 3
Pressure: 1500 psi
Temperature:125 °C
Solvent: 2-propanol : HPLC water (50 : 50)

Soil extraction – Sodium hydroxide:
The basic extraction method was used for investigation of the sorbed cationic component. After decantation of the aqueous phase, the soil was extracted with 10 mL aqueous sodium hydroxide solution 0.1 mol/L : acetonitrile (50 : 50) for 30 min at 70 °C. The extraction was repeated twice, the extracts were transferred quantitatively into a 50 mL measuring flask and filled up to the mark with the extraction medium. Aliquots were diluted with the extract of a blank sample to calibration range.

Samples for method validation:
Samples were prepared as described above (‘Preparation of the soil samples (conditioning)’). The aqueous phases were decanted and spiked with test item at 1 x LOQ level. Additional aqueous phase conditioned with LUFA soil 2.4 was spiked with test item at 10 x LOQ level. Blank samples were prepared accordingly but without spiking with test item. All samples were diluted with methanol containing 0.2% formic acid by factor 2. The samples of 10 x LOQ level were additionally diluted with dilution medium by factor 2 to calibration range for analysis of C10-, C11- and C12- alkylbenzene sulfonic acid.

Sample storage:
All samples were stored at room temperature prior and after analysis. The stability of calibration standards and samples after dilution with acetonitrile was confirmed during method development (non-GLP).
Matrix no.:
#2
Matrix type:
loamy sand
% Clay:
8.5
% Silt:
11.3
% Sand:
80.2
% Org. carbon:
1.47
pH:
>= 6.8 - <= 7.2
CEC:
7.6 other: mval/100 g
Matrix no.:
#3
Matrix type:
other: silty sand
% Clay:
0.412
% Silt:
8.6
% Sand:
29.3
% Org. carbon:
62.1
pH:
>= 6.8 - <= 7.5
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:
>= 6.9 - <= 7.6
CEC:
22 other: mval/100 g
Details on matrix:
Relevant Characteristics of Soils for Adsorption / Desorption
Soil Parameter
LUFA 2.2 LUFA 2.3 LUFA 2.4
Soil type (LUFA Soils)1) Loamy sand Silty sand Clayey loam
pH (0.01 M CaCl2)2) soil/solution ratio 1:5 6.8 7.5 7.6
pH (0.01 M CaCl2)2) soil/solution ratio 1:30 6.8 6.8 7.4
pH (0.01 M CaCl2)2) soil/solution ratio 1:100 7.2 6.9 6.9
Organic Carbon [%]3) 1.47 0.412 1.74
Clay (< 0.002 mm) [%]3) 8.5 8.6 25.2
Silt (0.002-0.063 mm) [%]3) 11.3 29.3 42.3
Sand (0.063-2 mm) [%]3) 80.2 62.1 32.6
Cation exchange capacity [mval/100 g] 3) 7.6 4.9 22
1) according to German DIN
2) determined during the course of the study
3) determined externally at AGROLAB GMBH (non-GLP)

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 differ significantly (organic carbon, clay content, cation exchange capacity and soil texture).

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



Date of receipt:
LUFA 2.2 (batch: F2.24016): 2016-10-24
LUFA 2.3 (batch: F2.34116): 2016-10-24
LUFA 2.4 (batch: F2.44116): 2016-10-24

Storage at test facility:
Room temperature, in closed containers

Expiry date:
According to test facility standard operation procedure, the expiry date was set to five years after receipt of the soils.
LUFA 2.2 (batch: F2.24016): 2021-10-24
LUFA 2.3 (batch: F2.34116): 2021-10-24
LUFA 2.4 (batch: F2.44116): 2021-10-24

Characterization date:
The soils were characterized in relation to their organic carbon content and cation exchange capacity externally at Agrolab GmbH.
LUFA 2.2 (batch: F2.24016): from 2017-02-14 to 2017-02-21
LUFA 2.3 (batch: F2.34116): from 2017-02-14 to 2017-02-21
LUFA 2.4 (batch: F2.44116): from 2017-02-14 to 2017-02-21

CaCl2 solution:
Deionised water was used to prepare the CaCl2 solution (0.01 M).

Soil / Solution ratio:
Due to different adoption behavior of active ingredients, Tier 2 was performed with soil / solution ratios:

For C10-, C11- and C12- alkylbenzene sulfonic acid: 1:30 and 1:5
For N,N-dimethyl-1,3-propanediamine: 1:100

Agitation:
By horizontal shaker at 150 rpm or by overhead shaker. Frequency was adjusted to avoid sedimentation of soil particles during equilibration.
Details on test conditions:
CaCl2 solution:
Deionised water was used to prepare the CaCl2 solution (0.01 M).

Soil / Solution ratio:
Due to different adoption behavior of active ingredients, Tier 2 was performed with soil / solution ratios:
For C10-, C11- and C12- alkylbenzene sulfonic acid: 1:30 and 1:5
For N,N-dimethyl-1,3-propanediamine: 1:100

Agitation:
By horizontal shaker at 150 rpm or by overhead shaker. Frequency was adjusted to avoid sedimentation of soil particles during equilibration.

Test temperature:
20 +/- 2 °C 
Key result
Sample No.:
#1
Type:
Kd
Value:
65 L/kg
pH:
6.8
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:5
% Org. carbon:
1.47
Remarks on result:
other: C10-alkylbenzene sulfonic acid
Key result
Sample No.:
#1
Type:
Koc
Value:
4 407 L/kg
pH:
6.8
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:5
% Org. carbon:
1.47
Remarks on result:
other: C10-alkylbenzene sulfonic acid
Key result
Sample No.:
#1
Type:
other: Kdes
Value:
211 L/kg
pH:
6.8
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:5
% Org. carbon:
1.47
Remarks on result:
other: C10-alkylbenzene sulfonic acid
Key result
Sample No.:
#2
Type:
Kd
Value:
6 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: C10-alkylbenzene sulfonic acid
Key result
Sample No.:
#2
Type:
Koc
Value:
1 462 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: C10-alkylbenzene sulfonic acid
Key result
Sample No.:
#2
Type:
other: Kdes
Value:
33 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: C10-alkylbenzene sulfonic acid
Key result
Sample No.:
#3
Type:
Kd
Value:
179 L/kg
pH:
7.6
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio
% Org. carbon:
1.74
Remarks on result:
other: C10-alkylbenzene sulfonic acid
Key result
Sample No.:
#3
Type:
Koc
Value:
10 278 L/kg
pH:
7.6
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:5
% Org. carbon:
1.74
Remarks on result:
other: C10-alkylbenzene sulfonic acid
Key result
Sample No.:
#3
Type:
other: Kdes
Value:
194 L/kg
pH:
7.6
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:5
% Org. carbon:
1.74
Remarks on result:
other: C10-alkylbenzene sulfonic acid
Key result
Sample No.:
#4
Type:
Koc
Value:
175 L/kg
pH:
6.8
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:5
% Org. carbon:
1.47
Remarks on result:
other: C11-alkylbenzene sulfonic acid
Key result
Sample No.:
#4
Type:
Koc
Value:
11 915 L/kg
pH:
6.8
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:5
% Org. carbon:
1.47
Remarks on result:
other: C11-alkylbenzene sulfonic acid
Key result
Sample No.:
#4
Type:
other: Kdes
Value:
187 L/kg
pH:
6.8
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:5
% Org. carbon:
1.47
Remarks on result:
other: C11-alkylbenzene sulfonic acid
Key result
Sample No.:
#5
Type:
Kd
Value:
13 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: C11-alkylbenzene sulfonic acid
Key result
Sample No.:
#5
Type:
Koc
Value:
3 138 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: C11-alkylbenzene sulfonic acid
Key result
Sample No.:
#5
Type:
other: Kdes
Value:
51 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: C11-alkylbenzene sulfonic acid
Key result
Sample No.:
#6
Type:
Kd
Value:
85 L/kg
pH:
7.4
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:30
% Org. carbon:
1.74
Remarks on result:
other: C11-alkylbenzene sulfonic acid
Key result
Sample No.:
#6
Type:
Koc
Value:
4 862 L/kg
pH:
7.4
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:30
% Org. carbon:
1.74
Remarks on result:
other: C11-alkylbenzene sulfonic acid
Key result
Sample No.:
#6
Type:
other: Kdes
Value:
984 L/kg
pH:
7.4
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:30
% Org. carbon:
1.74
Remarks on result:
other: C11-alkylbenzene sulfonic acid
Key result
Sample No.:
#7
Type:
Kd
Value:
93 L/kg
pH:
6.8
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:30
% Org. carbon:
1.47
Remarks on result:
other: C12-alkylbenzene sulfonic acid
Key result
Sample No.:
#7
Type:
Koc
Value:
6 298 L/kg
pH:
6.8
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:30
% Org. carbon:
1.47
Remarks on result:
other: C12-alkylbenzene sulfonic acid
Key result
Sample No.:
#7
Type:
other: Kdes
Value:
939 L/kg
pH:
6.8
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:30
% Org. carbon:
1.47
Remarks on result:
other: C12-alkylbenzene sulfonic acid
Key result
Sample No.:
#8
Type:
Kd
Value:
27 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: C12-alkylbenzene sulfonic acid
Key result
Sample No.:
#8
Type:
Koc
Value:
6 627 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: C12-alkylbenzene sulfonic acid
Key result
Sample No.:
#8
Type:
other: Kdes
Value:
79 L/kg
pH:
7.5
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:5
% Org. carbon:
0.412
Remarks on result:
other: C12-alkylbenzene sulfonic acid
Key result
Sample No.:
#9
Type:
Kd
Value:
193 L/kg
pH:
7.4
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:30
% Org. carbon:
1.74
Remarks on result:
other: C12-alkylbenzene sulfonic acid
Key result
Sample No.:
#9
Type:
Koc
Value:
11 087 L/kg
pH:
7.4
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:30
% Org. carbon:
1.74
Remarks on result:
other: C12-alkylbenzene sulfonic acid
Key result
Sample No.:
#9
Type:
other: Kdes
Value:
1 034 L/kg
pH:
7.4
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:30
% Org. carbon:
1.74
Remarks on result:
other: C12-alkylbenzene sulfonic acid
Key result
Sample No.:
#10
Type:
Kd
Value:
143 L/kg
pH:
7.2
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:100
% Org. carbon:
1.47
Remarks on result:
other: N,N-dimethyl-1,3-propanediamine
Key result
Sample No.:
#10
Type:
Koc
Value:
9 695 L/kg
pH:
7.2
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:100
% Org. carbon:
1.47
Remarks on result:
other: N,N-dimethyl-1,3-propanediamine
Key result
Sample No.:
#10
Type:
other: Kdes
Value:
326 L/kg
pH:
7.2
Temp.:
20 °C
Matrix:
LUFA 2.2 soil/solution ratio 1:100
% Org. carbon:
1.47
Remarks on result:
other: N,N-dimethyl-1,3-propanediamine
Key result
Sample No.:
#11
Type:
Kd
Value:
205 L/kg
pH:
6.9
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:100
% Org. carbon:
0.412
Remarks on result:
other: N,N-dimethyl-1,3-propanediamine
Key result
Sample No.:
#11
Type:
Koc
Value:
49 859 L/kg
pH:
6.9
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:100
% Org. carbon:
0.412
Remarks on result:
other: N,N-dimethyl-1,3-propanediamine
Key result
Sample No.:
#11
Type:
other: Kdes
Value:
443 L/kg
pH:
6.9
Temp.:
20 °C
Matrix:
LUFA 2.3 soil/solution ratio 1:100
% Org. carbon:
0.412
Remarks on result:
other: N,N-dimethyl-1,3-propanediamine
Key result
Sample No.:
#12
Type:
Kd
Value:
515 L/kg
pH:
6.9
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:100
% Org. carbon:
1.74
Remarks on result:
other: N,N-dimethyl-1,3-propanediamine
Key result
Sample No.:
#12
Type:
Koc
Value:
29 590 L/kg
pH:
6.9
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:100
% Org. carbon:
1.74
Remarks on result:
other: N,N-dimethyl-1,3-propanediamine
Key result
Sample No.:
#12
Type:
other: Kdes
Value:
889 L/kg
pH:
6.9
Temp.:
20 °C
Matrix:
LUFA 2.4 soil/solution ratio 1:100
% Org. carbon:
1.74
Remarks on result:
other: N,N-dimethyl-1,3-propanediamine

Results– Temperature, Dry Weights, pH Values

Temperature

The temperature was in the range of 20 ± 2 °C during the course of the study.

Dry Weights

The dry weight of each solid matrix was determined.

 

Soil Dry Weights

Mean values (n = 3)

 

Soil type

LUFA 2.2

LUFA 2.3

LUFA 2.4

soil dry weight [%]

92.3

96.1

90.4

 

 pH Values

The pH values of the aqueous media of the test systems were measured before and after equilibration with the corresponding soils and after addition of the test item. Results are shown in the following table.

 

pH Values of the Aqueous Media

Soil / solution ratios 1:5, 1:30 and 1:100

Soil / solution ratio 1:5

Soil type

LUFA 2.2

LUFA 2.3

LUFA 2.4

 

0.01 M CaCl2

8.4

8.4

8.4

 

after soil contact

6.8

7.5

7.6

 

after addition of the test item

6.5

6.9

7.8

 

Soil / solution ratio 1:30

Soil type

LUFA 2.2

LUFA 2.3

LUFA 2.4

 

0.01 M CaCl2

7.2

7.2

7.2

 

after soil contact

6.8

6.8

7.4

 

after addition of the test item

7.0

6.9

7.5

 

Soil / solution ratio 1:100

Soil type

LUFA 2.2

LUFA 2.3

LUFA 2.4

 

0.01 M CaCl2

6.3

6.3

6.3

 

after soil contact

7.2

6.9

6.9

 

after addition of the test item

7.0

7.0

6.9

 

Results –C10-C13 alkylbenzene sulfonic acid

Results of Tier 1 -C10-C13 alkylbenzene sulfonic acid

During Tier 1 experiments have been conducted to find the optimal matrix / solution ratio for each matrix. Therefore, the amount adsorbed at equilibrium was determined. In addition, test item stability was demonstrated by measuring test item control samples with conditioned CaCl2 solution but without soil during the experiments. The mass balance and the test vessel adsorption was evaluated.

 

 

 Adsorption Experiments -C10-C13 alkylbenzene sulfonic acid

Experiments have been conducted in LUFA soils 2.2 and 2.4 using a soil / solution ratio of 1:20 and 1:40. Samples were taken after 24 and 48 hours and the aqueous phase was analysed. C10-, C11- and C12- alkylbenzene sulfonic acid were analysed for the anionic component of the test item, C10-C13 alkylbenzene sulfonic acid. The alkylbenzene sulfonic acids showed increasing adsorption with increasing alkyl chain lengths. The determined adsorption values are shown in the tables below. With regard to these results, a soil solution ratio of 1:30 and an agitation time of 48 h were selected for Tier 2 experiments.

Tier 1:LUFA 2.2 Soil / Solution Ratios 1:20 and 1:40 -
C10-C13 alkylbenzene sulfonic acid

Soil / Solution Ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Adsorption
C10 alkyl

benzene sulfonic acid[%]

Adsorption
C11 alkyl

benzene sulfonic acid[%]

Adsorption
C12 alkyl

benzene sulfonic acid[%]

1:20

6.25

24

32

61

85

48

40

65

86

1:40

6.25

24

30

52

72

48

26

50

73

 


 Tier 1:LUFA 2.4 Soil / Solution Ratios 1:20 and 1:40 -
C10-C13 alkylbenzene sulfonic acid

Soil / Solution Ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Adsorption
C10 alkyl

benzene sulfonic acid[%]

Adsorption
C11 alkyl

benzene sulfonic acid[%]

Adsorption
C12 alkyl

benzene sulfonic acid[%]

1:20

6.25

24

36

63

85

48

53

74

90

1:40

6.25

24

25

43

68

48

24

46

72

 

Test Item Stability in the Aqueous Phase-C10-C13 alkylbenzene sulfonic acid

The stability of the component C10-C13 alkylbenzene sulfonic acidwas verified by the recovery rates of test item control samples (84% to 113% related to the nominal concentration after 48 h). The test item control samples were prepared by conditioning 0.01 M CaCl2 solution with soil. After separation of the phases, the aqueous phase was spiked with the test item. The recovery rates obtained are shown in the tables below.

 

Tier 1:Test Item Control Samples LUFA 2.2 -C10-C13 alkylbenzene sulfonic acid

Soil / Solution Ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Recovery Rate
C10 alkyl

benzene sulfonic acid[%]

Recovery Rate
C11 alkyl

benzene sulfonic acid[%]

Recovery Rate
C12 alkyl

benzene sulfonic acid[%]

1:20

6.25

24

111

114

101

48

113

104

95

1:40

6.25

24

92

93

90

48

88

88

84

 


 Tier 1:Test Item Control Samples LUFA 2.4 -C10-C13 alkylbenzene sulfonic acid

Soil / Solution Ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Recovery Rate
C10 alkyl

benzene sulfonic acid[%]

Recovery Rate
C11 alkyl

benzene sulfonic acid[%]

Recovery Rate
C12 alkyl

benzene sulfonic acid[%]

1:20

6.25

24

90

94

90

48

89

89

85

1:40

6.25

24

101

97

92

48

90

95

86

 

 

Mass Balance and Test Vessel Adsorption -C10-C13 alkylbenzene sulfonic acid

To determine the mass balance after 48 h and the test vessel adsorption, samples with a soil / solution ratio of 1:20 were used. The soil was extracted by using accelerated solvent extraction (ASE) and the test vessels were extracted after removal of the soil. The parental mass balance was ≥ 87% for LUFA 2.2 and ≥ 84% for LUFA 2.4. For aged samples, no higher recoveries could be obtained. Although the mass balance was below 90%, the indirect method was used during Tier 2 by calculating the mass in the solid phase at each sampling point from the measured concentration in the aqueous phase, as test item stability has been confirmed by test item control samples. The recovery rates and mass balance are presented in the tables below.

The test vessel adsorption for C10-C13 alkylbenzene sulfonic acid was negligible (≤ 1.9%) and therefore not determined during Tier 2.

 


 Tier 1:Mass Balance LUFA 2.2 soil -C10-C13 alkylbenzene sulfonic acid
soil / solution ratio 1:20, applied test item concentration: 6250 µg/L, n=2

 

Sampling point


[h]

Recovery rate from aqueous phase
[%]

Recovery rate from test vessel
[%]

Recovery rate from solid phase
[%]

Mass balance1)

[%]

Adsorption
C10 alkyl

benzene sulfonic acid[%]

48

60

0.8

32

93

Adsorption
C11 alkyl

benzene sulfonic acid[%]

48

35

1.7

54

91

Adsorption
C12 alkyl

benzene sulfonic acid[%]

48

14

1.9

71

87

1)          Sum of aqueous phase, solid phase and test vessel

 

Tier 1:Mass Balance LUFA 2.4 soil -C10-C13 alkylbenzene sulfonic acid
soil / solution ratio 1:20, applied test item concentration: 6250 µg/L, n=2

 

Sampling point
[h]

Recovery rate from aqueous phase
[%]

Recovery rate from test vessel
[%]

Recovery rate from solid phase
[%]

Mass balance1)

[%]

Adsorption
C10 alkyl

benzene sulfonic acid[%]

48

55

0.3

29

84

Adsorption
C11 alkyl

benzene sulfonic acid[%]

48

33

0.6

51

85

Adsorption
C12 alkyl

benzene sulfonic acid[%]

48

16

1.0

71

88

1)          Sum of aqueous phase, solid phase and test vessel


Tier 2:Adsorption Kinetics -C10-C13 alkylbenzene sulfonic acid

The determination for adsorption kinetics was performed with a nominal test item concentration of 5.00 mg/L. This concentration was selected with regard to the LOQ of the analytical method. Two different soil / solution ratios were used for adsorption experiments, 1:5 and 1:30. Results are shown in the tables below for the respective alkylbenzene sulfonic acid. Dependent on the alkyl chain-length and the soil type, either the samples with the soil / solution ratio 1:5 or the samples of 1:30 were used for evaluation. Samples were agitated for 48 h and samples of the aqueous phase were measured at defined sampling points. In addition, test item control samples were analysed. The percentage of adsorption and recovery rate for the test item control are given after 48 h and this sampling was used to calculate the distribution coefficients Kd and the corresponding organic carbon normalized distribution coefficients KOC.

 

Measured Amounts in Aqueous Phase, Calculated Amount for Solid Matrices, Percent of Adsorption and Distribution Coefficients Kd and KOC for C10 alkylbenzene sulfonic acid

Applied test item concentration: 5000 µg/L, n = 2
equilibration time: 48 h

Soil type

msoil
[g]

Vaq
[mL]

madss[µg]

Kd
[mL/g]

KOC
[mL/g]

Adsorption
[%]

Recovery Control [%]1)

LUFA 2.2

3.69

20

92.3

65

4407

92

113

LUFA 2.3

3.84

20

53.7

6

1462

54

97

LUFA 2.4

3.62

20

97.0

179

10278

97

94

msoil          = used amount of soil (dry weight)

Vaq            = used volume of aqueous phase

madss         = amount adsorbed to soil

1)               = recovery related to initially measured (0 h) concentration

2)               = ½ LOQ was used for calculations since measured concentration was below the lowest
  calibration standard

 


 Measured Amounts in Aqueous Phase, Calculated Amount for Solid Matrices, Percent of Adsorption and Distribution Coefficients Kd and KOC for C11 alkylbenzene sulfonic acid

Applied test item concentration: 5000 µg/L, n = 2
equilibration time: 48 h

Soil type

msoil
[g]

Vaq
[mL]

madss[µg]

Kd
[mL/g]

KOC
[mL/g]

Adsorption
[%]

Recovery Control [%]1)

LUFA 2.2

3.69

20

97.0

175

11915

97

98

LUFA 2.3

3.84

20

71.3

13

3138

71

97

LUFA 2.4

0.904

30

108

85

4862

72

92

msoil          = used amount of soil (dry weight)

Vaq            = used volume of aqueous phase

madss         = amount adsorbed to soil

1)               = recovery related to initially measured (0 h) concentration

2)               = ½ LOQ was used for calculations since measured concentration was below the lowest
  calibration standard

Measured Amounts in Aqueous Phase, Calculated Amount for Solid Matrices, Percent of Adsorption and Distribution Coefficients Kd and KOC for C12 alkylbenzene sulfonic acid

Applied test item concentration: 5000 µg/L, n = 2
equilibration time: 48 h

Soil type

msoil
[g]

Vaq
[mL]

madss[µg]

Kd
[mL/g]

KOC
[mL/g]

Adsorption
[%]

Recovery Control [%]1)

LUFA 2.2

0.923

30

111

93

6298

74

81

LUFA 2.3

3.84

20

84.0

27

6627

84

88

LUFA 2.4

0.904

30

128

193

11087

85

94

msoil          = used amount of soil (dry weight)

Vaq            = used volume of aqueous phase

madss         = amount adsorbed to soil

1)               = recovery related to initially measured (0 h) concentration

 

Tier 3: Desorption Kinetics-C10-C13 alkylbenzene sulfonic acid

The desorption behavior of the test item was determined after 48 h adsorption. The following tables show the desorption coefficient Kdes. Since the desorption coefficient is higher than the adsorption coefficient Kd, the test item adsorption is assumed to be not completely reversible. As the concentration of the analytes was partly below the LOQ, desorption and Kdes had to be calculated with ½ LOQ. Calculated values are marked.

 

Percent of Desorption and Desorption Coefficient Kdes for
C10 alkylbenzene sulfonic acid

Applied test item concentration: 5000 µg/L, n = 2

Soil Type

msoil[g]

Vaq[mL]

mdesaq(eq) [µg]

madss(eq) [µg]

Kdes[mL/g]

Desorption [%]

LUFA 2.21)

3.69

20

2.31

92.3

211

3

LUFA 2.3

3.84

20

7.24

53.7

33

13

LUFA 2.41)

3.62

20

2.69

97.0

194

3

msoil          = used amount of soil (dry weight)

Vaq            = used volume of aqueous phase

mdesaq        = amount of test item measured in the aqueous phase after desorption step

(without entrained water)

madss          = amount of test item adsorbed to soil at equilibrium

1)               = measured values at 48 h were below LOQ, endpoints were calculated with ½ LOQ

 

Percent of Desorption and Desorption Coefficient Kdes for
C11 alkylbenzene sulfonic acid

Applied test item concentration: 5000 µg/L, n = 2

Soil Type

msoil[g]

Vaq[mL]

mdesaq(eq) [µg]

madss(eq) [µg]

Kdes[mL/g]

Desorption [%]

LUFA 2.21)

3.69

20

2.73

97.0

187

3

LUFA 2.3

3.84

20

6.62

71.3

51

9

LUFA 2.41)

0.904

30

3.51

108

984

3

msoil          = used amount of soil (dry weight)

Vaq            = used volume of aqueous phase

mdesaq        = amount of test item measured in the aqueous phase after desorption step

(without entrained water)

madss          = amount of test item adsorbed to soil at equilibrium

1)               = measured values at 48 h were below LOQ, endpoints were calculated with ½ LOQ


 

Percent of Desorption and Desorption Coefficient Kdes for
C12 alkylbenzene sulfonic acid

Applied test item concentration: 5000 µg/L, n = 2

Soil type

msoil[g]

Vaq[mL]

mdesaq(eq) [µg]

madss(eq) [µg]

Kdes[mL/g]

Desorption [%]

LUFA 2.21)

0.923

30

3.71

111

939

3

LUFA 2.3

3.84

20

5.18

84.0

79

6

LUFA 2.41)

0.904

30

3.98

128

1034

3

msoil          = used amount of soil (dry weight)

Vaq            = used volume of aqueous phase

mdesaq        = amount of test item measured in the aqueous phase after desorption step

(without entrained water)

madss          = amount of test item adsorbed to soil at equilibrium

1)               = measured values at 48 h were below LOQ, endpoints were calculated with ½ LOQ

 

The respective figures of the desorption kinetics show that the desorption equilibrium is not reached after 48 h. This effect is apparently related to the chemical composition of the test item or can be related to the specific properties of this component of the test item. The concentration of the analytes in the aqueous phase and the calculated desorption decrease over time (until concentration was below LOQ for some soils). As test item stability was confirmed by test item control samples during Tier 1 and Tier 2, the results can be explained by ongoing adsorption of the alkylbenzene sulfonic acids after renewal of the aqueous phase.

Discussion of the Results for C10-C13 alkylbenzene sulfonic acid

The experiments for adsorption and desorption kinetics showed that the adsorption of the alkylbenzene sulfonic acids to the soil particles takes place slowly. The adsorption equilibrium was not reached for each analysed compound using a soil / solution ratio of 1:30. As recommended by the guideline, evaluation of phenomena which lead to the steady decrease of the test item concentration in the aqueous phase was conducted.

 

As the results of the test item control samples measured during Tier 2 neither indicated depletion of the test item in the aqueous phase by adsorption processes on test vessels nor by degradation processes, the test item was considered to be stable in the test system over 48 h.

 

The impactof soil parameters on the adsorption / desorption behavior of a chemical substance was considered by the selection of soils which differ significantly in their composition and physical properties. The soil type apparently does not affect the achievement of the adsorption equilibrium and the ionisation of the alkylbenzene sulfonates is not affected by the pH value in the study range from 5.0 to 7.5.

 

To investigate the agitation time which is necessary to reach the adsorption equilibrium and to verify if an agitation time longer than 48 h (as recommended by the guideline) is applicable for the anionic compound, additional experiments have been conducted over a period of 168 h. The soil / solution ratio of 1:30 was used, as measured concentrations below the LOQ should be avoided. The results are summarized in the table below. Whereas the adsorption increased over time, the recovery rate for test item control samples decreased for the aqueous phase. At the same time, increasing test vessel adsorption was determined. The adsorption increased until the concentration in the aqueous phase was below the LOQ of the analytical method without showing an adsorption equilibrium in 168 h. Thus, longer agitation times than recommended by the guideline do not result in a definitive adsorption equilibrium and are therefore not applicable for this test item.

 

A higher soil / solution of 1:5 was used to obtain the adsorption equilibrium faster and these experiments were used for evaluation of the adsorption in suspensions of some soils.

 

 


 Additional Experiment – Agitation Time 168 h

Applied test item concentration: 5000 µg/L, soil /solution ratio: 1:30

C10 alkylbenzene sulfonic acid

Sampling

24 h

48 h

72 h

96 h

168 h

Soil Type

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

LUFA 2.2

29

n.d.

44

n.d.

56

105

71

104

85

101 (31))

LUFA 2.3

9

n.d.

12

n.d.

18

105

23

102

42

100 (31))

LUFA 2.4

33

n.d.

49

n.d.

69

98

79

97

95

96 (31))

C11 alkylbenzene sulfonic acid

Sampling

24 h

48 h

72 h

96 h

168 h

Soil Type

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

LUFA 2.2

54

n.d.

66

n.d.

70

94

84

89

94

76 (101))

LUFA 2.3

21

n.d.

28

n.d.

36

94

44

96

57

79 (121))

LUFA 2.4

56

n.d.

68

n.d.

83

91

89

90

97

81 (101))

C12 alkylbenzene sulfonic acid

Sampling

24 h

48 h

72 h

96 h

168 h

Soil Type

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

Ads
[%]

Control
[%]

LUFA 2.2

68

n.d.

78

n.d.

82

75

92

70

96

55 (281))

LUFA 2.3

45

n.d.

57

n.d.

56

75

65

85

77

51 (271))

LUFA 2.4

79

n.d.

83

n.d.

90

72

94

82

97

56 (291))

Ads              = adsorption calculated from concentration in aqueous phase, mean value of two replicates

Control        = recovery rate of the test item control sample related to nominal concentration, mean value of two

                       replicates

n.d.              = not determined

1)                  = test vessel adsorption [%]

 

With regard to the results obtained during the experiments over 168 h, a higher soil / solution ratio of 1:5 was chosen to accelerate the adsorption process. Inappropriately, high soil / solution ratios also enhance the test item depletion in the aqueous phase with the disadvantage that the certainty in thedetermination of the remaining test item concentration decreases. Measured concentrations were partly below the LOQ of the analytical method.

 

It is considered that the steady decrease of the test item in the aqueous phase is related to its chemical composition and the presence of the diamine which can work as a bridge between negative charges. To provide plausible values for Kd and KOC, data have been calculated for the best suitable soil / solution ratio (1:5 or 1:30) for each analyte regarding the degree of adsorption on the one hand and the measured concentrations on the other hand.

Results –N,N-dimethyl-1,3-propanediamine

Results of Tier 1 -N,N-dimethyl-1,3-propanediamine

During Tier 1, experiments have been conducted to find the optimal matrix / solution ratio and the time to reach equilibrium for each matrix. Therefore, the amount adsorbed at equilibrium was determined. In addition, test item stability was demonstrated by measuring test item control samples with conditioned CaCl2 solution but without soil during the experiments. The mass balance was evaluated.

 

 

Adsorption Experiments -N,N-dimethyl-1,3-propanediamine

Experiments have been conducted in LUFA soils 2.2 and 2.4 using a soil / solution ratio of 1:20 and 1:40. Samples were taken after 24 and 48 hours and the concentration of N,N-dimethyl-1,3-propanediamine was analysed in the aqueous phase. As the adsorption was high, measured concentrations were partly below the LOQ. Test item control samples (aqueous medium conditioned with soil, separated and spiked with the test item) showed stability of N,N-dimethyl-1,3-propanediamine in the test system.The determined adsorption values are shown in the table below. With regard to these results, a soil solution ratio of 1:100 and an agitation time of 24 h was selected for Tier 2 experiments.

 

Tier 1:Adsorption with Soil / Solution Ratios 1:20 and 1:40 -
N,N-dimethyl-1,3-propanediamine

Soil / solution ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Adsorption in LUFA 2.2 [%]

Adsorption in LUFA 2.4 [%]

1:20

6.25

24

93

98

48

98

99

1:40

6.25

24

90

95

48

92

98

 

 

Test Item Stability in the Aqueous Phase -N,N-dimethyl-1,3-propanediamine

The stability of the cationic component N,N-dimethyl-1,3-propanediamine was verified by the recovery rates of test item control samples (98% to 107% related to the nominal concentration after 48 h) in soil-conditioned 0.01 M CaCl2 solution. The determined values are shown in the table below.


 

 Tier 1:Test Item Control Samples -N,N-dimethyl-1,3-propanediamine

Soil / solution ratio

Applied concentration, test item [mg/L]

Sampling point [h]

Recovery rate
LUFA 2.2[%]

Recovery rate
LUFA 2.4[%]

1:20

6.25

24

109

104

48

100

102

1:40

6.25

24

103

103

48

107

98

 

Mass Balance and Test Vessel Adsorption -N,N-dimethyl-1,3-propanediamine

During preliminary investigations prior to the start of the study the extraction efficiency of the test item was evaluated by extraction of aged as well as freshly spiked soil samples. The soil was extracted with formic acid or trifluoroacetic acid at room temperature (three extraction steps for each method with ultrasonic treatment) resulting in a poor extraction efficiency. In addition, the soil was extracted by using ASE as described above for C10-C13 alkylbenzene sulfonic acid resulting in negligible recovery of N,N-dimethyl-1,3-propanediamine.

The highest extraction efficiency was obtained after basic extraction at higher temperatures To determine the mass balance after 48 h and the test vessel adsorption during Tier 1, samples with a soil / solution ratio of 1:20 were used. The soil was extracted with sodium hydroxide at 70 °C. The parental mass balance was 28% for LUFA 2.2 and 18% for LUFA 2.4. Although the basic extraction resulted in the highest recovery, the recovery of the cationic component of the test item was still insufficient to fulfil the mass balance requirements of the guideline. Though the mass balance was below 90%, due to strong adsorption of the analyte to soil and bad extraction efficiency, the stability of the component could be confirmed by the results of the test item control samples in conditioned 0.01 M CaCl2 solution. Therefore, the indirect method was used during Tier 2 by calculating the mass in the solid phase at each sampling point from the measured concentration in the aqueous phase.

 

Adsorption to the test vessel was negligible and test vessel adsorption was therefore not evaluated during Tier 2.


 Tier 1:Mass Balance -N,N-dimethyl-1,3-propanediamine
soil / solution ratio 1:20, applied test item concentration: 6250 µg/L, n=2

 

Sampling point


[h]

Recovery rate from aqueous phase
[%]

Recovery rate from test vessel
[%]

Recovery rate from solid phase
[%]

Mass balance1)

[%]

Recovery rate in LUFA 2.2 [%]

48

2

0

26

28

Recovery rate in LUFA 2.4 [%]

48

1

0

18

18

1)          Sum of aqueous phase, solid phase and test vessel

 

Tier 2:Adsorption Kinetics -N,N-dimethyl-1,3-propanediamine

The determination for adsorption kinetics was performed with a nominal test item concentration of 6.00 mg/L at a soil / solution ratio of 1:100. This concentration was selected with regard to the LOQ of the analytical method. Results are shown in the table below. Samples were agitated for 24 h and samples of the aqueous phase were measured at defined sampling points and the percentage of adsorption is given at adsorption equilibrium (LUFA 2.2 after 6 h, LUFA 2.3 and 2.4 after 24 h). In addition, test item control samples were analysed after 24 h. N,N-dimethyl-1,3-propanediamine adsorbs strongly to the soils.

 

Time to Reach Adsorption Equilibrium, Measured Amounts in Aqueous Phase, Calculated Amount for Solid Matrices, Percent of Adsorption and Distribution Coefficients Kd and KOC for N,N-dimethyl-1,3-propanediamine

Applied test item concentration: 6000 µg/L, n = 2
agitation time: 24 h

Soil type

msoil
[g]

Vaq
[mL]

teq
[h]

madss
[µg]

Kd
[mL/g]

KOC
[mL/g]

Adsorption
[%]

Recovery Control [%]1)

LUFA 2.2

0.923

100

6

341

143

9695

57

104

LUFA 2.3

0.961

100

24

398

205

49859

66

97

LUFA 2.4

0.904

100

24

494

515

29590

82

105

msoil          = used amount of soil (dry weight)

Vaq            = used volume of aqueous phase

teq              = time to reach adsorption equilibrium

madss         = amount adsorbed to soil

1)               = recovery related to initially measured (0 h) concentration

Tier 3: Desorption Kinetics -N,N-dimethyl-1,3-propanediamine

The desorption behavior of the test item was determined after 24 h adsorption. The table below shows the desorption coefficient Kdes. Since the desorption coefficient is higher than the adsorption coefficient Kd, the test item adsorption is assumed to be not completely reversible.

 

Time to Reach Desorption Equilibrium, Percent of Desorption and Desorption Coefficient Kdes for N,N-dimethyl-1,3-propanediamine

Applied test item concentration: 6000 µg/L, n = 2

Soil Type

msoil
[g]

Vaq
[mL]

teq
[h]

mdesaq(eq)
[µg]

madss(eq)
[µg]

Kdes
[mL/g]

Desorption
[%]

LUFA 2.2

0.923

100

6

85.0

341

326

25

LUFA 2.3

0.961

100

24

75.7

398

443

19

LUFA 2.4

0.904

100

24

54.7

494

889

11

msoil          = used amount of soil (dry weight)

Vaq            = used volume of aqueous phase

teq            = time to reach desorption equilibrium

mdesaq        = amount of test item measured in the aqueous phase after desorption step

(without entrained water)

madss          = amount of test item adsorbed to soil at equilibrium


 

Validity criteria fulfilled:
yes
Conclusions:
Valid study performed according to the guidelines under GLP conditions using slightly adapted conditions
Executive summary:

The adsorption / desorption behavior of the test item Benzenesulfonic acid, C10-13-alkyl derivs., compds with N,N-dimethyl-1, 3-propanediamine (batch no.2629-89-10) was investigated in three different soils according to OECD guideline 106 and EC C.18. Distribution coefficients Kd and organic carbon normalized distribution coefficients KOC were determined with a single concentration and the desorption behavior / reversibility of the adsorption from the soils was investigated. The test item consists of two components, C10-C13 alkylbenzene sulfonic acid(anionic component) and N,N-dimethyl-1,3-propanediamine(cationic component). Partitioning of both components was evaluated during this study.

 

For the anionic component, C10-C13 alkylbenzene sulfonic acid, three analytes were detected. Experiments have been conducted in LUFA soils 2.2, 2.3 and 2.4 with soil / solution ratios 1:5 and 1:30 as the adsorption is dependent on the soil type and the alkyl chain-length and increases with increasing chain-length. A concentration of 5.00 mg/L was used and the endpoints were calculated after 48 h agitation (time to reach equilibrium). The table below shows the determined distribution coefficients Kd and the corresponding organic carbon normalized distribution coefficients KOC. Furthermore, the mobility of the test item in the investigated matrices was classified according to McCall et al.(1980) and the desorption coefficient Kdes is presented in the summarizing table. The adsorption was determined to be not completely reversible.

 

Summarized Endpoints-C10-C13 alkylbenzene sulfonic acid

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 type

Soil / solution ratio

Kd[mL/g]

KOC[mL/g]

Kdes [mL/g]

Mobility according to McCall et al.

C10-alkylbenzene sulfonic acid

LUFA 2.2

1:5

65

4407

211

slight

LUFA 2.3

1:5

6

1462

33

low

LUFA 2.4

1:5

179

10278

194

immobile

 

C11-alkylbenzene sulfonic acid

LUFA 2.2

1:5

175

11915

187

immobile

LUFA 2.3

1:5

13

3138

51

slight

LUFA 2.4

1:30

85

4862

984

slight

 

C12-alkylbenzene sulfonic acid

LUFA 2.2

1:30

93

6298

939

immobile

LUFA 2.3

1:5

27

6627

79

immobile

LUFA 2.4

1:30

193

11087

1034

immobile

For the anionic compound, because MS is used for quantification the sorption of the three main constituent (C10, 11 and 12) on these soils were measured. The sorption of the three constituents on these three soils are presented in the table above and the mean of the sorption on the three soils is used for risk assessment. To be able to calculate the mean information on the content of the three constituents is needed.

The content of C10 in the anionic product is 20.8%

The content of C11 in the anionic product is 42.8%

The content of C12 in the anionic product is 29.9%

 

Mean Koc = ((0.208*4407 + 0.428*11915 + 0.299*6298) + (0.208*1462 + 0.428*3138 + 0.299*6627) + (0.208*10278 + 0.428*4862 + 0.299*11087))/3

Mean Koc = ((7899.378) + (3628.633) + (7533.773))/3 = 6353.9 L/kg

 

Thus for the anionic compound of the salt, the mean Koc is 6353.9 L/kg

The cationic component N,N-dimethyl-1,3-propanediamine showed strong adsorption to the soils. All experiments were conducted with a nominal concentration of 6.00 mg/L with agitation for 24 h and a soil / solution ratio of 1:100. N,N-dimethyl-1,3-propanediamine is immobile in all tested soils with irreversible adsorption.The table below shows the determined distribution coefficients Kd and the correspondingorganic carbon normalized distribution coefficients KOC. Furthermore, the mobility of the test item in the investigated matrices was classified according to McCall et al.(1980) and the desorption coefficient Kdes is shown.

Summarized Endpoints -N,N-dimethyl-1,3-propanediamine

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 type

Soil / solution ratio

t (eq)
[h]

Kd
[mL/g]

KOC
[mL/g]

Kdes 
[mL/g]

Mobility according to McCallet al.

N,N-dimethyl-1,3-propanediamine

 

LUFA 2.2

1:100

6

143

9695

326

immobile

LUFA 2.3

1:100

24

205

49859

443

immobile

LUFA 2.4

1:100

24

515

29590

889

immobile

teq           = time to reach adsorption equilibrium

For the cationic compound, the mean Kd is 287.7 L/kg (mean of 143, 205 and 515 L/Kg). For the cationic product the Koc will not be used.

For the cationic product the normalization of the sorption constant to the organic carbon content of the soil is considered wrong. Instead of the Koc the Kd will be used as ethylene diamine will only sorb based on ionic interaction and not via hydrophobic interaction with the organic matter fraction in the soils.

In risk assessment Kd’s can as easily be used as the Koc.

Description of key information

In the sorption/desorption study the sorption of Benzenesulfonic acid, C10-13-alkyl derivs., compds with N,N-dimethyl-1, 3-propanediamine to three soils has been evaluated; Lufa 2.2, 2.3 and 2.4. The test substance is a salt which consists of an anionic (Benzenesulfonic acid, C10 -13 -alkyl derivs) and a cationic part (N,N-dimethyl-1, 3-propanediamine).

The anionic part consists of different constituents where the C10, 11 and 12 are the main constituents.

 

For the anionic compound, because MS is used for quantification the sorption of the three main constituent (C10, 11 and 12) on these soils were measured. The sorption of the three constituents on these three soils are presented table 1 and the mean of the sorption on the three soils is used for risk assessment. To be able to calculate the mean information on the content of the three constituents is needed.

The content of C10 in the anionic product is 20.8%

The content of C11 in the anionic product is 42.8%

The content of C12 in the anionic product is 29.9%

 

Mean Koc = ((0.208*4407 + 0.428*11915 + 0.299*6298) + (0.208*1462 + 0.428*3138 + 0.299*6627) + (0.208*10278 + 0.428*4862 + 0.299*11087))/3

Mean Koc = ((7899.378) + (3628.633) + (7533.773))/3 = 6353.9 L/kg

 

Thus for the anionic compound of the salt, the mean Koc is 6353.9 L/kg

 

For the cationic compound, the mean Kd is 287.7 L/kg (mean of 143, 205 and 515 L/Kg). For the cationic product the Koc will not be used.

For the cationic product the normalization of the sorption constant to the organic carbon content of the soil is considered wrong. Instead of the Koc the Kd will be used as ethylene diamine will only sorb based on ionic interaction and not via hydrophobic interaction with the organic matter fraction in the soils.

In risk assessment Kd’s can as easily be used as the Koc.

Key value for chemical safety assessment

Koc at 20 °C:
6 353.9

Other adsorption coefficients

Type:
other: Kd of the cationic part of the salt
Value in L/kg:
287.7
at the temperature of:
20 °C

Additional information

The adsorption / desorption behavior of the test item Benzenesulfonic acid, C10-13-alkyl derivs., compds with N,N-dimethyl-1, 3-propanediamine was investigatedin three different soils according to OECD guideline 106 and EC C.18. Distribution coefficients Kd and organic carbon normalized distribution coefficients KOC were determined with a single concentration and the desorption behavior / reversibility of the adsorption from the soils was investigated. The test item consists of two components, C10-C13 alkylbenzene sulfonic acid(anionic component) and N,N-dimethyl-1,3-propanediamine (cationic component). Partitioning of both components in the presence of each other was evaluated during this study.

 

For the anionic component, C10-C13 alkylbenzene sulfonic acid, three analytes were detected. Experiments have been conducted in LUFA soils 2.2, 2.3 and 2.4 with soil / solution ratios 1:5 and 1:30 as the adsorption is dependent on the soil type and the alkyl chain-length and increases with increasing chain-length. A concentration of 5.00 mg/L was used and the endpoints were calculated after 48 h agitation (time to reach equilibrium). The table below shows the determined distribution coefficients Kd and the 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) and the desorption coefficient Kdes is presented in the summarizing table. The adsorption was determined to be not completely reversible.

Summarized Endpoints-C10-C13 alkylbenzene sulfonic acid

Mobility according to McCallet 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 type

Soil / solution ratio

Kd[mL/g]

KOC[mL/g]

Kdes [mL/g]

Mobility according to McCallet al.

C10-alkylbenzene sulfonic acid

LUFA 2.2

1:5

65

4407

211

slight

LUFA 2.3

1:5

6

1462

33

low

LUFA 2.4

1:5

179

10278

194

immobile

 

C11-alkylbenzene sulfonic acid

LUFA 2.2

1:5

175

11915

187

immobile

LUFA 2.3

1:5

13

3138

51

slight

LUFA 2.4

1:30

85

4862

984

slight

 

C12-alkylbenzene sulfonic acid

LUFA 2.2

1:30

93

6298

939

immobile

LUFA 2.3

1:5

27

6627

79

immobile

LUFA 2.4

1:30

193

11087

1034

immobile

For the anionic compound, because MS is used for quantification the sorption of the three main constituent (C10, 11 and 12) on these soils were measured. The sorption of the three constituents on these three soils are presented in the table above and the mean of the sorption on the three soils is used for risk assessment. To be able to calculate the mean, information on the content of the three constituents is needed.

The content of C10 in the anionic product is 20.8%

The content of C11 in the anionic product is 42.8%

The content of C12 in the anionic product is 29.9%

 

Mean Koc = ((0.208*4407 + 0.428*11915 + 0.299*6298) + (0.208*1462 + 0.428*3138 + 0.299*6627) + (0.208*10278 + 0.428*4862 + 0.299*11087))/3

Mean Koc = ((7899.378) + (3628.633) + (7533.773))/3 = 6353.9 L/kg

 

Thus for the anionic compound of the salt, the mean Koc is 6353.9 L/kg

The cationic component N,N-dimethyl-1,3 -propanediamine showed strong adsorption to the soils. All experiments were conducted with a nominal concentration of 6.00 mg/L with agitation for 24 h and a soil / solution ratio of 1:100. N,N-dimethyl-1,3-propanediamine is immobile in all tested soils with irreversible adsorption. The table below shows the determined distribution coefficients Kd and the 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) and the desorption coefficient Kdes is shown.

Summarized Endpoints -N,N-dimethyl-1,3-propanediamine

Mobility according to McCallet 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 type

Soil / solution ratio

t (eq)
[h]

Kd
[mL/g]

KOC
[mL/g]

Kdes 
[mL/g]

Mobility according to McCallet al.

N,N-dimethyl-1,3-propanediamine

 

LUFA 2.2

1:100

6

143

9695

326

immobile

LUFA 2.3

1:100

24

205

49859

443

immobile

LUFA 2.4

1:100

24

515

29590

889

immobile

teq           = time to reach adsorption equilibrium

For the cationic compound, the mean Kd is 287.7 L/kg (mean of 143, 205 and 515 L/Kg). For the cationic product the Koc will not be used.

For the cationic product the normalization of the sorption constant to the organic carbon content of the soil is considered wrong. Instead of the Koc the Kd will be used as ethylene diamine will only sorb based on ionic interaction and not via hydrophobic interaction with the organic matter fraction in the soils.

In risk assessment Kd’s can as easily be used as the Koc.

[LogKoc: 3.803]