Reaction products of acrylonitrile and 2,2’-Iminodi(ethylamine), hydrogenated

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019-06-24 to 2019-10-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Council Regulation (EC) No. 440/2008, Method C.18 (2008)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

batch equilibrium method

Media:

soil

Test material

Test material information

Constituent 1

Reference substance name:

Reaction products of acrylonitrile and 2,2’-Iminodi(ethylamine), hydrogenated

EC Number:

810-418-2

Cas Number:

1703784-30-8

IUPAC Name:

Reaction products of acrylonitrile and 2,2’-Iminodi(ethylamine), hydrogenated

Test material form:

liquid

Details on test material:

Trade name Ortegol LA 2

CAS-No. 1703784-30-8

Batch number 2298695

Active substance/ 2-propenenitrile, reaction products with diethylenetriamine, hydrogenated

Purity 100% / mixture of different chain lengths and branched structures

Components / Aminopropyldiethylenetriamine APDETA / 6.2%
Content (certified) Bis-Aminopropyldiethylenetriamine BAPDETA / 64.3%
Tris- Aminopropyldiethylenetriamine TAPDETA / 24.0%

Appearance colorless - light yellowish liquid

Expiry date 2019-12-31

Recommended storage At room temperature, protected from light, under N2 in the tightly closed container in a dry, cool (room temperature), well-ventilated area

Radiolabelling:

no

Study design

Test temperature:

Nominal: 20 - 25 °C

Batch equilibrium or other method

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
Disposable centrifugation tubes (polypropylene) and disposable glass bottles

Concentration for adsorption experiments
50 mg test item /L
15.8 mg test item /L
5 mg test item /L (concentration used for adsorption / desorption kinetics)
1.58 mg test item /L
0.5 mg test item /L

Stock solutions
Stock solutions of 10 and 1 g/L of the test item in ultrapure water were prepared.

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.
As aqueous stock solutions were used for spiking, max. 0.5 volume-% of these stock solutions were used in order to adjust the test concentrations. Afterwards, the samples were agitated.

Samples for analysis
The soil suspensions were centrifuged after agitation at 4000 rpm to separate the phases, followed by analysing the concentration of the test item in aqueous phase by LC-MS. For analysis of the soil, the aqueous phase was decanted and the soil was extracted. Extracts were also analysed by LC-MS.

Replicates
All samples were prepared in duplicate.

Sampling points
Tier 2: 0.5 h, 1 h, 2 h, 4 h
Tier 3: 2h, 24 h for desorption isotherms


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. For adsorption isotherm, the lowest test item loading level was used as concentration for test item control replicates.

Replicates
Duplicates (tier 1 and tier 2)

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.

Dispersion treatment
Agitation

Sample Preparation Tier 1

Dilution medium
Acetonitrile containing 10 mM perfluoro heptanoic acid and 2% formic acid : 0.01 M CaCl2 solution conditioned with the respective soil ( 50 : 50 )

Standards
A stock solution of 10 g test item/L in ultrapure water was prepared. The solution was diluted to 7 calibration standards in the range of 20 to 200 µg test item/L with dilution medium.

Aqueous phase
After centrifugation, an aliquot of each aqueous sample was stabilized by dilution with acetonitrile containing 10 mM perfluoro heptanoic acid and 2% formic acid (factor 2).

Soil extraction
The wet soil was used for extraction after decantation of the aqueous phase. The soil was extracted at 20 -25 °C. 30 mL methanol : ultrapure water (75 : 25 v/v) containing 0.3 mol/L sodium hydroxide were added to the wet soil. An ultrasonic bath was used for 10 min. The vessel was shaken for 60 min. The suspensions were centrifuged at 4000 rpm for 5 min. The extraction was repeated twice without the use of the ultrasonic bath. During the third extraction cycle the vessel was shaken for 30 min. The extracts were transferred quantitatively into a 100 mL measuring flask and filled up with methanol : ultrapure water (75 : 25 v/v) containing 0.3 mol/L sodium hydroxide.


Sample Preparation Tier 2 and Tier 3

Dilution medium
Acetonitrile : ultrapure water (90 : 10) containing 0.05%(v/v) heptafluorobutyric acid : 0.01 M CaCl2 solution conditioned with the respective soil (50 : 50)

Standards
A stock solution of 10 g test item/L in ultrapure water was prepared. The solution was diluted to 6 calibration standards in the range of 50 to 500 µg test item/L with dilution medium.

Aqueous phase
After centrifugation, an aliquot of each aqueous sample was stabilized by dilution with acetonitrile : ultrapure water (90 : 10) containing 0.05%(v/v) heptafluorobutyric acid (factor 2).

Soil extraction
See above for tier 1.

Matrix properties

Matrix properties 1

Matrix no.:

#1

Matrix type:

other: silty sand

% Clay:

4.1

% Silt:

10.5

% Sand:

85.4

% Org. carbon:

0.718

pH:

6.1

CEC:

2.4 other: mval/100 g

Matrix properties 2

Matrix no.:

#2

Matrix type:

loamy sand

% Clay:

8.5

% Silt:

11.3

% Sand:

80.2

% Org. carbon:

1.47

pH:

6.8

CEC:

7.6 other: mval/100 g

Matrix properties 3

Matrix no.:

#3

Matrix type:

other: silty sand

% Clay:

8.6

% Silt:

29.3

% Sand:

62.1

% Org. carbon:

0.412

pH:

6.9

CEC:

4.9 other: mval/100 g

Matrix properties 4

Matrix no.:

#4

Matrix type:

clay loam

% Clay:

23.3

% Silt:

38.6

% Sand:

38.1

% Org. carbon:

1.85

pH:

7.4

CEC:

22 other: mval/100 g

Matrix properties 5

Matrix no.:

#5

Matrix type:

other: Dystric Cambisol

% Clay:

17.6

% Silt:

35

% Sand:

47.4

% Org. carbon:

3.12

pH:

6.5

CEC:

8.5 other: mval/100 g

Details on matrix:

Reason for the selection
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.
Tier 1 was conducted with LUFA soils 2.2 and 2.4.

Origin of soils
Landwirtschaftliche Untersuchungs- und Forschungsanstalt LUFA Speyer, Obere Langgasse 40, 67346 Speyer, Germany
European Commission Joint Research Centre, Institute for Reference Materials and Measurements IRMM, Retieseweg, B-2440 Geel, Belgium

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: 1:10, 1:40 and 1:100
Tier 2 and Tier 3: 1:100

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


Test temperature
The temperature was mainly in the range of 20 to 25 °C during the course of the study. Deviation from this temperature range occurred only for brief periods (< 1h) with a temperature between 18 and 20 °C.The test temperature reached a minimum of 18.6 °C during the study for a short period. Regulation of the air conditioning was occasionally necessary for a couple of minutes. This caused that the temperature dropped.
This deviation is considered to have no negative impact on the integrity and quality of the study.

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Key result

Sample No.:

#1

Type:

Kd

Value:

782 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.1 soil/solution ratio 1:100

% Org. carbon:

0.718

Remarks on result:

other: Bis-Aminopropyldiethylenetriamine BAPDETA

Adsorption coefficient 2

Key result

Sample No.:

#1

Type:

Koc

Value:

108 956 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.1 soil/solution ratio 1:100

% Org. carbon:

0.718

Remarks on result:

other: Bis-Aminopropyldiethylenetriamine BAPDETA

Adsorption coefficient 3

Key result

Sample No.:

#2

Type:

Kd

Value:

2 658 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.2 soil/solution ratio 1:100

% Org. carbon:

1.47

Remarks on result:

other: Bis-Aminopropyldiethylenetriamine BAPDETA

Adsorption coefficient 4

Key result

Sample No.:

#2

Type:

Koc

Value:

180 810 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.2 soil/solution ratio 1:100

% Org. carbon:

1.47

Remarks on result:

other: Bis-Aminopropyldiethylenetriamine BAPDETA

Adsorption coefficient 5

Key result

Sample No.:

#3

Type:

Kd

Value:

2 181 L/kg

pH:

9.4

Temp.:

20 °C

Matrix:

LUFA 2.3 soil/solution ratio 1:100

% Org. carbon:

0.412

Remarks on result:

other: Bis-Aminopropyldiethylenetriamine BAPDETA

Adsorption coefficient 6

Key result

Sample No.:

#3

Type:

Koc

Value:

529 473 L/kg

pH:

9.4

Temp.:

20 °C

Matrix:

LUFA 2.3 soil/solution ratio 1:100

% Org. carbon:

0.412

Remarks on result:

other: Bis-Aminopropyldiethylenetriamine BAPDETA

Adsorption coefficient 7

Key result

Sample No.:

#4

Type:

Kd

Value:

3 869 L/kg

pH:

9.2

Temp.:

20 °C

Matrix:

LUFA 2.4 soil/solution ratio 1:100

% Org. carbon:

1.85

Remarks on result:

other: Bis-Aminopropyldiethylenetriamine BAPDETA

Adsorption coefficient 8

Key result

Sample No.:

#4

Type:

log Koc

Value:

209 160 L/kg

pH:

9.2

Temp.:

20 °C

Matrix:

LUFA 2.4 soil/solution ratio 1:100

% Org. carbon:

1.85

Remarks on result:

other: Bis-Aminopropyldiethylenetriamine BAPDETA

Adsorption coefficient 9

Key result

Sample No.:

#5

Type:

Kd

Value:

2 193 L/kg

pH:

7.6

Temp.:

20 °C

Matrix:

Eurosoil 3 soil/solution ratio 1:100

% Org. carbon:

3.12

Remarks on result:

other: Bis-Aminopropyldiethylenetriamine BAPDETA

Adsorption coefficient 10

Key result

Sample No.:

#5

Type:

Koc

Value:

70 300 L/kg

pH:

7.6

Temp.:

20 °C

Matrix:

Eurosoil 3 soil/solution ratio 1:100

% Org. carbon:

3.12

Remarks on result:

other: Bis-Aminopropyldiethylenetriamine BAPDETA

Adsorption coefficient 11

Key result

Sample No.:

#1

Type:

Kd

Value:

1 304 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.1 soil/solution ratio 1:100

% Org. carbon:

0.718

Remarks on result:

other: Tris- Aminopropyldiethylenetriamine TAPDETA

Adsorption coefficient 12

Key result

Sample No.:

#1

Type:

Koc

Value:

181 555 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.1 soil/solution ratio 1:100

% Org. carbon:

0.718

Remarks on result:

other: Tris- Aminopropyldiethylenetriamine TAPDETA

Adsorption coefficient 13

Key result

Sample No.:

#2

Type:

Kd

Value:

2 605 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.2 soil/solution ratio 1:100

% Org. carbon:

1.47

Remarks on result:

other: Tris- Aminopropyldiethylenetriamine TAPDETA

Adsorption coefficient 14

Key result

Sample No.:

#2

Type:

Koc

Value:

177 242 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.2 soil/solution ratio 1:100

% Org. carbon:

1.47

Remarks on result:

other: Tris- Aminopropyldiethylenetriamine TAPDETA

Adsorption coefficient 15

Key result

Sample No.:

#3

Type:

Kd

Value:

2 283 L/kg

pH:

9.4

Temp.:

20 °C

Matrix:

LUFA 2.3 soil/solution ratio 1:100

% Org. carbon:

0.412

Remarks on result:

other: Tris- Aminopropyldiethylenetriamine TAPDETA

Adsorption coefficient 16

Key result

Sample No.:

#3

Type:

Koc

Value:

554 042 L/kg

pH:

9.4

Temp.:

20 °C

Matrix:

LUFA 2.3 soil/solution ratio 1:100

% Org. carbon:

0.412

Remarks on result:

other: Tris- Aminopropyldiethylenetriamine TAPDETA

Adsorption coefficient 17

Key result

Sample No.:

#4

Type:

Kd

Value:

3 792 L/kg

pH:

9.2

Temp.:

20 °C

Matrix:

LUFA 2.4 soil/solution ratio 1:100

% Org. carbon:

1.85

Remarks on result:

other: Tris- Aminopropyldiethylenetriamine TAPDETA

Adsorption coefficient 18

Key result

Sample No.:

#4

Type:

Koc

Value:

204 979 L/kg

pH:

9.2

Temp.:

20 °C

Matrix:

LUFA 2.4 soil/solution ratio 1:100

% Org. carbon:

1.85

Remarks on result:

other: Tris- Aminopropyldiethylenetriamine TAPDETA

Adsorption coefficient 19

Key result

Sample No.:

#5

Type:

Kd

Value:

2 188 L/kg

pH:

7.6

Temp.:

20 °C

Matrix:

Eurosoil 3 soil/solution ratio 1:100

% Org. carbon:

3.12

Remarks on result:

other: Tris- Aminopropyldiethylenetriamine TAPDETA

Adsorption coefficient 20

Key result

Sample No.:

#5

Type:

Koc

Value:

70 131 L/kg

pH:

7.6

Temp.:

20 °C

Matrix:

Eurosoil 3 soil/solution ratio 1:100

% Org. carbon:

3.12

Remarks on result:

other: Tris- Aminopropyldiethylenetriamine TAPDETA

Adsorption coefficient 21

Key result

Sample No.:

#1

Type:

Kd

Value:

75 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.1 soil/solution ratio 1:100

% Org. carbon:

0.718

Remarks on result:

other: Aminopropyldiethylenetriamine APDETA

Adsorption coefficient 22

Key result

Sample No.:

#1

Type:

Koc

Value:

10 477 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.1 soil/solution ratio 1:100

% Org. carbon:

0.718

Remarks on result:

other: Aminopropyldiethylenetriamine APDETA

Adsorption coefficient 23

Key result

Sample No.:

#2

Type:

Kd

Value:

1 068 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.2 soil/solution ratio 1:100

% Org. carbon:

1.47

Remarks on result:

other: Aminopropyldiethylenetriamine APDETA

Adsorption coefficient 24

Key result

Sample No.:

#2

Type:

Koc

Value:

72 663 L/kg

pH:

8.7

Temp.:

20 °C

Matrix:

LUFA 2.2 soil/solution ratio 1:100

% Org. carbon:

1.47

Remarks on result:

other: Aminopropyldiethylenetriamine APDETA

Adsorption coefficient 25

Key result

Sample No.:

#3

Type:

Kd

Value:

1 612 L/kg

pH:

9.4

Temp.:

20 °C

Matrix:

LUFA 2.3 soil/solution ratio 1:100

% Org. carbon:

0.412

Remarks on result:

other: Aminopropyldiethylenetriamine APDETA

Adsorption coefficient 26

Key result

Sample No.:

#3

Type:

Koc

Value:

391 310 L/kg

pH:

9.4

Temp.:

20 °C

Matrix:

LUFA 2.3 soil/solution ratio 1:100

% Org. carbon:

0.412

Remarks on result:

other: Aminopropyldiethylenetriamine APDETA

Adsorption coefficient 27

Key result

Sample No.:

#4

Type:

Kd

Value:

3 470 L/kg

pH:

9.2

Temp.:

20 °C

Matrix:

LUFA 2.4 soil/solution ratio 1:100

% Org. carbon:

1.85

Remarks on result:

other: Aminopropyldiethylenetriamine APDETA

Adsorption coefficient 28

Key result

Sample No.:

#4

Type:

Koc

Value:

187 593 L/kg

pH:

9.2

Temp.:

20 °C

Matrix:

LUFA 2.4 soil/solution ratio 1:100

% Org. carbon:

1.85

Remarks on result:

other: Aminopropyldiethylenetriamine APDETA

Adsorption coefficient 29

Key result

Sample No.:

#5

Type:

Kd

Value:

3 139 L/kg

pH:

7.6

Temp.:

20 °C

Matrix:

Eurosoil 3 soil/solution ratio 1:100

% Org. carbon:

3.12

Remarks on result:

other: Aminopropyldiethylenetriamine APDETA

Adsorption coefficient 30

Key result

Sample No.:

#5

Type:

Koc

Value:

100 606 L/kg

pH:

7.6

Temp.:

20 °C

Matrix:

Eurosoil 3 soil/solution ratio 1:100

% Org. carbon:

3.12

Remarks on result:

other: Aminopropyldiethylenetriamine APDETA

Any other information on results incl. tables

Results

Tier 1–Adsorption, Stability in the Test System and Test Vessel Adsorption

LUFA 2.4 was used for the first experiment for preliminary investigations on the adsorption behavior of the test item with soil / solution ratios of 1:10 and 1:40 at a concentration of 0.5 mg test item/L. Samples of the aqueous phase were taken after 4 h agitation. For both soil / solution ratios, the test item depletion in the aqueous phase was nearly quantitative(see table below). Because of the high adsorption, an additional experiment was conducted with a soil / solution of 1:100. For LUFA 2.2, the adsorption was determined only with a soil / solution ratio of 1:100. Although the test item concentration also decreased below the lowest calibration level, this soil / solution ratio was used for any further assessment, as it is the lowest technical feasible soil / solution ratio.

 

Tier 1: LUFA 2.2 andLUFA 2.4 – Adsorption Experiments

n = 2, aqueous phase was analysed

BAPDETA
Soil Type	Soil / Solution Ratio	Applied concentration, test item [mg/L]	Applied concentration, component [mg/L]	Sampling point [h]	Adsorption [%]^1
LUFA 2.4	1:10	0.5 mg/L	0.323 mg/L	4	> 96
	1:40	0.5 mg/L	0.323 mg/L	4	> 96
	1:100	0.5 mg/L	0.323 mg/L	4	> 96
LUFA 2.2	1:100	0.5 mg/L	0.323 mg/L	4	> 96
TAPDETA
Soil Type	Soil / Solution Ratio	Applied concentration, test item [mg/L]	Applied concentration, component [mg/L]	Sampling point [h]	Adsorption [%]^1
LUFA 2.4	1:10	0.5 mg/L	0.121 mg/L	4	> 96
	1:40	0.5 mg/L	0.121 mg/L	4	> 96
	1:100	0.5 mg/L	0.121 mg/L	4	95
LUFA 2.2	1:100	0.5 mg/L	0.121 mg/L	4	91
				24	100
APDETA
Soil Type	Soil / Solution Ratio	Applied concentration, test item [mg/L]	Applied concentration, component [mg/L]	Sampling point [h]	Adsorption [%]^1
LUFA 2.4	1:10	0.5 mg/L	0.0312 mg/L	4	> 96
	1:40	0.5 mg/L	0.0312 mg/L	4	> 96
	1:100	0.5 mg/L	0.0312 mg/L	4	> 96
LUFA 2.2	1:100	0.5 mg/L	0.0312 mg/L	4	> 96

1             =           measured concentrations were below the lowest calibration level 20 µg test item/L (LCL)

The test item control samples, samples with conditioned 0.01M CaCl₂ solution but without soil, were stable over 24 h and 48 h, respectively, and verified the stability of the test item in the test system (without soil) (see table below). Test vessel adsorption was not observed, as the test item control samples did not show any decline of the test item.

 

Tier 1: LUFA 2.2 and LUFA 2.4 – Test Item Control Samples

n=2

BAPDETA
Soil Type	Soil / Solution Ratio	Applied concentration, test item [mg/L]	Applied concentration, component [mg/L]	Sampling point [h]	Recovery Rate [%]
LUFA 2.4	1:10	0.5 mg/L	0.323 mg/L	24	101
	1:40	0.5 mg/L	0.323 mg/L	24	104
	1:100	0.5 mg/L	0.323 mg/L	48	93
LUFA 2.2	1:100	0.5 mg/L	0.323 mg/L	48	92
TAPDETA
Soil Type	Soil / Solution Ratio	Applied concentration, test item [mg/L]	Applied concentration, component [mg/L]	Sampling point [h]	Recovery Rate [%]
LUFA 2.4	1:10	0.5 mg/L	0.121 mg/L	24	105
	1:40	0.5 mg/L	0.121 mg/L	24	105
	1:100	0.5 mg/L	0.121 mg/L	48	97
LUFA 2.2	1:100	0.5 mg/L	0.121 mg/L	48	100
APDETA
Soil Type	Soil / Solution Ratio	Applied concentration, test item [mg/L]	Applied concentration, component [mg/L]	Sampling point [h]	Recovery Rate [%]
LUFA 2.4	1:10	0.5 mg/L	0.0312 mg/L	24	104
	1:40	0.5 mg/L	0.0312 mg/L	24	104
	1:100	0.5 mg/L	0.0312 mg/L	48	94
LUFA 2.2	1:100	0.5 mg/L	0.0312 mg/L	48	94

 

 

As an additional experiment, LUFA 2.2 was used with a soil / solution ratio of 1:100 and a test item concentration of 5 mg/L. The aqueous phase was measured at different sampling points. To proof, if the adsorption to soil is reasonable for the decline of the test item in the aqueous phase, additional replicates were spiked after sterilization with HgCl₂. As the recovery rates for samples with and without sterilization were comparable (low), no biodegradation took place over the evaluated period of 1 h (see table below).

 

Tier 1: LUFA 2.2 – Adsorption Experiments

n = 2; aqueous phase was analysed; soil / solution ratio = 1:100

BAPDETA
Sample Type	Applied concentration, test item [mg/L]	Applied concentration, component [mg/L]	Sampling point [h]	Adsorption [%]
without HgCl2	5 mg/L	3.22 mg/L	1	98^1
with HgCl2	5 mg/L	3.22 mg/L	1	97
TAPDETA
Soil / Solution Ratio	Applied concentration, test item [mg/L]	Applied concentration, component [mg/L]	Sampling point [h]	Adsorption [%]
without HgCl2	5 mg/L	1.20 mg/L	1	99^1
with HgCl2	5 mg/L	1.20 mg/L	1	> 99^1
APDETA
Soil / Solution Ratio	Applied concentration, test item [mg/L]	Applied concentration, component [mg/L]	Sampling point [h]	Adsorption [%]
without HgCl2	5 mg/L	0.310 mg/L	1	88
with HgCl2	5 mg/L	0.310 mg/L	1	85

 

1    =       measured concentrations for one replicate were below the lowest calibration level 20 µg test item/L (LCL)

 

 

 

Tier 1– Extraction from Soil /fresh Spikes

Various solvents and devices have been tested on freshly spiked soils. Positive results were obtained with an extraction solvent containing sodium hydroxide.

A summary of the tested extraction methods used is given in the following table.

 

The test item is highly adsorptive to soils. Even after extensive method development, no extraction was found to be quantitative.

Extraction using Methanol : water mixtures and sodium hydroxide was used for mass balance experiments.

 

Tier 1– Method Development Soil Extraction – Fresh Spikes

Applied test item: 100 µg to LUFA 2.4, n = 2

Extraction method	Recovery rate BAPDETA [%]	Recovery rate TAPDETA [%]	Recovery rate APDETA [%]
Methanol:water 80:20 + 2% formic acid, RT	n.d.	n.d.	n.d.
Methanol + 1% TFA, RT	n.d.	n.d.	n.d.
Acetonitrile + 12.5 mM PFHA + 1% FA, RT	n.d.	n.d.	n.d.
Methanol : 2-Propanol 50:50, ASE	n.d.	n.d.	n.d.
Methanol : water 50:50 + 0.2 mol/L NaOH, RT, 2 cycles 1 h	42	53	39
Methanol : water 50:50 + 0.2 mol/L NaOH, RT, 2 cycles 1 h, 3^rdcycles overnight	48	61	49
Methanol : water 50:50 + 0.1 mol/L NaOH, ASE	n.d.	n.d.	15
Methanol : water 50:50 + 0.2 mol/L NaOH, RT, 3 cycles 1 h	37	37	34
Methanol : water 75:25 + 0.2 mol/L NaOH, RT, 3 cycles 1 h	64	77	50
Methanol : water 75:25 + 0.3 mol/L NaOH, RT, 3 cycles 1 h	86	90	67
Methanol : water 75:25 + 0.3 mol/L NaOH, RT, 2 cycles 1 h, 3^rdcycle overnight	61	80	55

n.d.          =            not detected

RT            =            room temperature

ASE           =            Accelerated solvent extractor

 

Tier 1– Mass Balance

 

Experiments regarding the mass balance were conducted during tier 1 with LUFA 2.2 and LUFA 2.4 with a concentration of 5 mg test item/L and sampling after 4 h adsorption. LUFA soil 2.4 was assumed to reflect the worst case scenario due to high amounts of cationic exchange capacity, organic carbon and clay. The extraction method at room temperature using methanol : water 75:25 containing 0.3 mol/L NaOH was used.

The resulting recoveries obtained with this method are shown inTable 18. Due to technical problems, only the soil extracts could be analysed. As the adsorption is expected to be > 95% from results of former experiments, and the obtained recovery rates were below 85% (except for LUFA 2.4 replicate 2), the mass balances were found to be below 90%. Therefore, analyses of both phases, aqueous phase and soil phase had to be conducted during tier 2 and tier 3.

 

Tier 1:Mass Balance

Soil / solution ratio:  1:100, sampling after 4 h

Applied test item concentration = 5 mg/L

 

Soil Type	Replicate	Recovery Soil BAPDETA [%]	Recovery Soil TAPDETA [%]	Recovery Soil APDETA [%]
LUFA 2.2	1	76	77	70
	2	80	80	73
LUFA 2.4	1	78	82	74
	2	87	94	85

 

Tier 2 – Adsorption Kinetics

The determination for adsorption kinetics was performed with a nominal test item concentration of 5 mg test item/L. A soil / solution ratio of 1:100 was used for all soils. The concentrations of the test item were measured in aqueous phase and soil extracts at defined sampling points. The sampling points were 0.5 h, 1 h, 2 h and 4 h. For each soil, the adsorption equilibrium was reached after 2 h of agitation. Mass balances after 4 h were between 62% and 93%. As test item stability was confirmed during tier 1, these recovery rates indicate very strong adsorption to the soils and the low extraction efficiency for the test item. K_d and K_OC values were calculated from calculated amounts in the aqueous and the solid phase (direct method). The results for the different compounds are shown in the tables below.

In parallel, test item control samples verified the test item stability in the test system without soil. The results for the test item control samples are shown in the forth table below. Recovery rates were partly above 120%, probably due to solvation effects. Nevertheless, since the 4 h aged samples were in the range of 96% to 109% related to the initially measured concentration, the stability was confirmed.

 

Tier 2 - Adsorption Kinetics - BAPDETA

Equilibrium Time, Measured Amounts in Aqueous Phase and Soil Extracts, K_d and K_OC

Applied concentration, test item:          5 mg/L

Applied concentration, BAPDETA:       3.22 mg/L

n = 2, t_eq= 2 h

Soil Type	Vaq [mL]	msoil [g]	m^adsaq [µg]	m^adssoil [µg]	Ads [%]	MB [%]	OC [%]	Kd [ml/g]	KOC [ml/g]
LUFA 2.1	100	0.969	30.1	228	91	80	0.718	782	108956
LUFA 2.2	100	0.928	12.5	224	97	73	1.47	2658	180810
LUFA 2.3	100	0.961	12.2	256	97	83	0.412	2181	529473
LUFA 2.4	100	0.887	7.92	272	98	87	1.85	3869	209160
Eurosoil 3	100	0.982	10.6	229	98	74	3.12	2193	70300

t_eq           =                time to reach adsorption equilibrium

m_{test item}      =                Applied amount, test item

V_aq            =                used volume of aqueous phase

m_soil          =                used amount of soil (dry weight)

m^ads_aq        =                amount of test item in the aqueous phase after adsorption equilibrium was reached (mean value of 2 h and 4 h sampling)

m^ads_soil       =                amount of test item in the soil after 4 h of agitation

Ads           =                adsorption after 4 h of agitation, based on depletion of the compound from aqueous phase

MB           =                mass Balance after 4 h of agitation

%OC         =                percentage of organic carbon content in the soil

 

 

Tier 2- AdsorptionKinetics - TAPDETA

Equilibrium Time, Measured Amounts in Aqueous Phase and Soil Extracts, K_d and K_OC

Applied concentration, test item:          5 mg/L

Applied concentration, TAPDETA:       1.20 mg/L

n = 2, t_eq= 2 h

Soil Type	Vaq [mL]	msoil [g]	m^adsaq [µg]	m^adssoil [µg]	Ads [%]	MB [%]	OC [%]	Kd [ml/g]	KOC [ml/g]
LUFA 2.1	100	0.969	8.28	105	94	93	0.718	1304	181555
LUFA 2.2	100	0.928	4.77	98	97	85	1.47	2605	177242
LUFA 2.3	100	0.961	4.74	104	97	90	0.412	2283	554042
LUFA 2.4	100	0.887	3.14	106	98	90	1.85	3792	204979
Eurosoil 3	100	0.982	4.58	98.4	98	84	3.12	2188	70131

 

 

Tier 2 - Adsorption Kinetics - APDETA

Equilibrium Time, Measured Amounts in Aqueous Phase and Soil Extracts, K_d and K_OC values

Applied concentration, test item:          5 mg/L

Applied concentration, TAPDETA:       0.310 mg/L

n = 2, t_eq= 2 h

Soil Type	Vaq [mL]	msoil [g]	m^adsaq [µg]	m^adssoil [µg]	Ads [%]	MB [%]	OC [%]	Kd [ml/g]	KOC [ml/g]
LUFA 2.1	100	0.969	12.8	9.33	62	68	0.718	75	10477
LUFA 2.2	100	0.928	2.84	17.4	92	65	1.47	1068	72663
LUFA 2.3	100	0.961	1.38	21.3	96	73	0.412	1612	391310
LUFA 2.4	100	0.887	0.762	23.5	98	78	1.85	3470	187593
Eurosoil 3	100	0.982	0.602	18.6	98	62	3.12	3139	100606

t_eq             =                time to reach adsorption equilibrium

m_{test item}      =                Applied amount, test item

V_aq            =                used volume of aqueous phase

m_soil          =                used amount of soil (dry weight)

m^ads_aq        =                amount of test item in the aqueous phase after adsorption equilibrium was reached (mean value of 2 h and 4 h sampling)

m^ads_soil       =                amount of test item in the soil after 4 h of agitation

Ads           =                adsorption after 4 h of agitation, based on depletion of the compound from aqueous phase

MB            =                mass Balance after 4 h of agitation

%OC         =                percentage of organic carbon content in the soil

 

Tier 2 - Adsorption Kinetics – Test Item Control Samples

Applied concentration, test item: 5 mg/L; n = 2

 

Soil Type	Sampling Point	Recovery Rate [%]^1
		LUFA 2.1	LUFA 2.2	LUFA 2.3	LUFA 2.4	Eurosoil 3
BAPDETA	0 h	116	127	113	126	123
	4 h	99	103	97	107	97
TAPDETA	0 h	136	140	125	133	134
	4 h	109	108	104	108	98
APDETA	0 h	92	87	102	122	95
	4 h	98	102	107	96	102

1)               0h: Recovery rate of the nominal concentration

4h: Recovery rate of the initially measured concentration

 

 

 

Tier 3– Desorption

Desorption of the test item was monitored after adsorption for 4 h. The aqueous phase was analysed at three different sampling points 1 h, 3 h and 24 h. The percent of desorption after 24 h and the values for K_des and K_des^OC are given in the following table. For LUFA 2.3 and LUFA 2.4, measured values were below the lowest calibration standard. For LUFA 2.2 and Eurosoil 3, the desorption was calculated to be 3% to 4%. For LUFA 2.1, significant desorption was observed for APDETA. Therefore, desorption was tested depending on applied concentration (desorption isotherm) for this soil.

 

Tier 3 - Desorption Kinetics

Recovery in Aqueous Phase, K_des and K_des^OC values

Applied concentration, test item: 5 mg/L

n = 2, t_des= 24 h

	BAPDETA			TAPDETA			APDETA
Soil Type	Des [%]	Kdes [ml/g]	Kdes^OC [ml/g]	Des [%]	Kdes [ml/g]	Kdes^OC [ml/g]	Des [%]	Kdes [ml/g]	Kdes^OC [ml/g]
LUFA 2.1	4	2	323	4	2	317	19	0	60
LUFA 2.2	3	4	263	3	4	246	4	2	168
LUFA 2.3	< LCL	-	-	< LCL	-	-	< LCL	-	-
LUFA 2.4	< LCL	-	-	< LCL	-	-	< LCL	-	-
Eurosoil 3	3	3	108	3	3	93	3	3	109

t_des            =                duration of desorption experiment, after 4 h adsorption

< LCL        =                measured values were below lowest calibration standard

Des           =                desorption after 24 h

 

Five concentrations 0.500, 1.58, 5.0, 15.8 and 50 mg test item/L were used for determination of the desorption isotherm. Desorption samples were prepared after 2 h adsorption and were taken after 24 h desorption. The measured concentrations did not show a linear correlation in the concentration range tested.

 

Tier 3– Adsorption Isotherms

The adsorption isotherm was determined with the concentrations of 0.500, 1.58, 5.0, 15.8 and 50 mg test item/L after an agitation time of 2 h hours. Soil extracts and aqueous phase were analysed. As the adsorption was high (> 90%, except for LUFA 2.1 APDETA) in tier 2, the measured concentration in the lower applied concentrations were expected to be below the lowest calibration level in the aqueous phase during adsorption isotherm analysis. However, the concentrations were unexpected high in some measurements, which is not plausible if a linear correlation between concentration and adsorption is assumed. But as the test item control samples with a nominal concentration of 0.500 mg test item /L showed good recoveries, spiking and analytical method were verified.

In addition, the measured test item concentration in higher concentrations did not show a linear correlation either. The mass balances, moreover, indicate a reduced extraction efficiency in higher concentrations.

The tables below show the calculated adsorption isotherms for each soil. If measured values were below the lowest calibration standards, these values were approximated from adsorption in tier 2. As 1/n of the linear Freundlich isotherm is expected to be in the range of 0.7 to < 1.0 and r²> 0.975 indicates the applicability of the linear isotherm, it is obvious that the Freundlich model is not valid for the test item PU-2018-821 in the tested concentration range.

 

Tier 3 - Freundlich AdsorptionIsotherms- BAPDETA

Applied test item concentrations K₁ to K₅:= 50.0, 15.8, 5.00, 1.58, 0.500 mg/L

Applied concentrations BAPDETA K₁ to K₅:= 31.2, 10.2, 3.22, 1.02, 0.322 mg/L

n = 2

 

Soil Type	msoil [g]	Vaq [mL]	r^2	1/n	MB [%]	Control^10 h [%]	Control^22 h [%]
LUFA 2.1	0.969	100	0.45	0.24	59-147	83	105
LUFA 2.2	0.928	100	0.58	0.43	56-153	95	107
LUFA 2.3	0.961	100	0.45	0.32	90-139	99	100
LUFA 2.4	0.887	100	0.50	0.71	103-131	92	108
Eurosoil 3	0.982	100	0.74	0.62	69-142	98	102

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

V_aq     = Volume aqueous phase [mL]

n        = regression constant

MB     = mass balance, range of replicates mean value is given, for details see section 10.3

1           = recovery rate test item control from nominal, K5, mean value of two replicates

2           = recovery rate test item control from initial, K5, mean value of two replicates

 

 

 

 

 

 

Tier 3- Freundlich Adsorption Isotherms - TAPDETA

Applied test item concentrations K₁ to K₅ := 50.0, 15.8, 5.00, 1.58, 0.500 mg/L

Applied concentrations TAPDETA K₁ to K₅ := 12.0, 3.79, 1.20, 0.379, 0.120 mg/L

n = 2

 

Soil Type	msoil [g]	Vaq [mL]	r^2	1/n	MB [%]	Control^10 h [%]	Control^12 h [%]
LUFA 2.1	0.969	100	0.92	0.64	81-152	85	113
LUFA 2.2	0.928	100	0.91	0.57	100-132	110	110
LUFA 2.3	0.961	100	0.56	0.37	93-139	100	107
LUFA 2.4	0.887	100	0.49	0.70	102-120	95	111
Eurosoil 3	0.982	100	0.81	0.77	75-141	105	105

 

Tier 3 - Freundlich Adsorption Isotherms - APDETA

Applied test item concentrations K₁ to K₅ := 50.0, 15.8, 5.00, 1.58, 0.500 mg/L

Applied concentrations APDETA K₁ to K₅ := 3.10, 0.980, 0.310, 0.0980, 0.0310 mg/L

n = 2

 

Soil Type	msoil [g]	Vaq [mL]	r^2	1/n	MB [%]	Control^10 h [%]	Control^22 h [%]
LUFA 2.1	0.969	100	0.39	0.15	73-215	93	100
LUFA 2.2	0.928	100	0.021	0.052	44-110	87	109
LUFA 2.3	0.961	100	0.74	0.30	71-103	95	99
LUFA 2.4	0.887	100	0.60	0.50	44-80	98	102
Eurosoil 3	0.982	100	0.81	0.42	66-116	99	107

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

V_aq    = Volume aqueous phase [mL]

n      = regression constant

MB   = mass balance, range of replicates mean value is given, for details see section 10.3

1           = recovery rate test item control from nominal, K5, mean value of two replicates

2           = recovery rate test item control from initial, K5, mean value of two replicates

 

 

It should be mentioned, that the linear concentration range is often limited for highly adsorptive test items. Whereas the soil is “overloaded” in higher concentration ranges, the decline of the test item in the aqueous phase leads to difficulties regarding the accuracy of the analytical method in low concentration ranges.

 

Because the test item showed no linear Freudlich adsorption behaviour, additional distribution coefficients K_d and organic carbon normalized distribution coefficients K_OC were calculated for all concentrations and all soils.

 

Individual Distribution Coefficients K_d - BAPDETA

Applied test item concentrations K₁ to K₅:= 50.0, 15.8, 5.00, 1.58, 0.500 mg/L

Applied concentrations BAPDETA K₁ to K₅:= 31.2, 10.2, 3.22, 1.02, 0.322 mg/L

n = 2

 

ApplicationConcentration	Kd
	LUFA 2.1	LUFA 2.2	LUFA 2.3	LUFA 2.4	Eurosoil 3
K1	9	66	17	616	108
K2	51	755	262	10695	643
K3	221	3315	3151	4417	3048
K4	815	1303	1042	1197	857
K5	365	619	486	454	366

 

Individual Distribution Coefficients K_d - TAPDETA

Applied test item concentrations K₁to K₅:= 50.0, 15.8, 5.00, 1.58, 0.500 mg/L

Applied concentrations TAPDETA K₁to K₅:= 12.0, 3.79, 1.20, 0.379, 0.120 mg/L

n = 2

 

ApplicationConcentration	Kd
	LUFA 2.1	LUFA 2.2	LUFA 2.3	LUFA 2.4	Eurosoil 3
K1	64	218	27	725	299
K2	197	954	351	13213	615
K3	325	3822	2761	5343	3177
K4	723	1133	746	1260	713
K5	326	4634	-	469	351

 

 

 

Individual Distribution Coefficients K_d - APDETA

Applied test item concentrations K₁to K₅:= 50.0, 15.8, 5.00, 1.58, 0.500 mg/L

Applied concentrations APDETA K₁to K₅:= 3.10, 0.980, 0.310, 0.0980, 0.0310 mg/L

n = 2

 

ApplicationConcentration	Kd
	LUFA 2.1	LUFA 2.2	LUFA 2.3	LUFA 2.4	Eurosoil 3
K1	8	4	17	104	38
K2	8	149	41	9230	546
K3	15	2773	2128	4100	3330
K4	786	3299	2321	1508	3491
K5	436	3847	2352	2351	3680

 

Individual Carbon Normalized Distribution Coefficients K_OC - BAPDETA

Applied test item concentrations K₁ to K₅:= 50.0, 15.8, 5.00, 1.58, 0.500 mg/L

Applied concentrations BAPDETA K₁ to K₅:= 31.2, 10.2, 3.22, 1.02, 0.322 mg/L

n = 2

 

ApplicationConcentration	KOC
	LUFA 2.1	LUFA 2.2	LUFA 2.3	LUFA 2.4	Eurosoil 3
K1	1190	4465	4194	33289	3446
K2	7142	51352	63618	578083	20596
K3	30823	225528	764764	238759	97678
K4	113548	88610	252811	64721	27479
K5	50784	42106	117898	24554	11723

 

 

 

Individual Carbon Normalized Distribution Coefficients K_OC - TAPDETA

Applied test item concentrations K₁ to K₅:= 50.0, 15.8, 5.00, 1.58, 0.500 mg/L

Applied concentrations TAPDETA K₁ to K₅:= 12.0, 3.79, 1.20, 0.379, 0.120 mg/L

n = 2

 

ApplicationConcentration	KOC
	LUFA 2.1	LUFA 2.2	LUFA 2.3	LUFA 2.4	Eurosoil 3
K1	8862	14855	6585	39215	9576
K2	27498	64881	85205	714216	19719
K3	45290	259997	670208	288821	101816
K4	100679	77055	181131	68105	22856
K5	45368	315206	-	25349	11257

 

 

Individual Carbon Normalized Distribution Coefficients K_OC - APDETA

Applied test item concentrations K₁ to K₅:= 50.0, 15.8, 5.00, 1.58, 0.500 mg/L

Applied concentrations APDETA K₁ to K₅:= 3.10, 0.980, 0.310, 0.0980, 0.0310 mg/L

n = 2

 

ApplicationConcentration	KOC
	LUFA 2.1	LUFA 2.2	LUFA 2.3	LUFA 2.4	Eurosoil 3
K1	1158	245	4152	5627	1222
K2	1095	10154	9863	498900	17501
K3	2104	188624	516575	221606	106729
K4	109488	224401	563384	81538	111888
K5	60692	261686	570753	127083	117938

 

 

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

Summary

General Information

The adsorption / desorption behavior of the test item PU-2018-821 (batch no. 2298695) was investigated in five different soils according to OECD guideline 106 and Council Regulation (EC) No. 440/2008, C.18 from 2019-06-24 to 2019-10-15 at Noack Laboratorien GmbH, 31157 Sarstedt, Germany.

Distribution coefficients K_d and organic carbon normalized distribution coefficients K_OC were determined with a single concentration. Furthermore, investigations about the adsorption as a function of the test item loading level (Freundlich adsorption isotherms) in the aqueous phase were performed. Three components of the test item, Aminopropyldiethylenetriamine (APDETA), Bis-aminopropyldiethylenetriamine (BAPDETA) and tris-aminopropyldiethylenetriamine (TAPDETA) were analysed by LC-MS/MS. With an overall yield of 94.5%, these components are suitable to investigate the adsorption/desorption behavior of the test item. Determined adsorption coefficients are given for the individual components as well as for the product itself, taking into account the respective amounts.

Relevant properties of the used soils are given in Table 1 below. Experiments for adsorption kinetics were conducted with a nominal test item concentration of 5 mg test item/L (K₃). Additional concentrations of 50.0, 15.8, 5.00, 1.58, 0.500 mg/L (K₁, K₂, K₃, K₄, K₅) were used for the determination of the Freundlich adsorption isotherms.

Table1:      RelevantCharacteristics of Test Matrices

	Soils
	LUFA 2.1	LUFA 2.2	LUFA 2.3	LUFA 2.4	Eurosoil 3
batch	F2.1 2817	F2.2 4016	F2.3 4116	F2.4 2617	160718
Soil Type^1)	Silty sand^1)	Loamy sand^1)	Silty sand^1)	Clayey loam^1)	Dystric Cambisol^4)
pH (0.01 M CaCl2)^3)	4.9	5.4	5.9	7.4	5.5^5)
Organic Carbon [%]^2)	0.718	1.47	0.412	1.85	3.12
Clay (<0.002 mm) [%]^2)	4.1	8.5	8.6	23.3	17.6
Silt (0.002-0.063 mm) [%]^2)	10.5	11.3	29.3	38.6	35.0
Sand (0.063-2 mm) [%]^2)	85.4	80.2	62.1	38.1	47.4
Cation Exchange Capacity [mval/100g]^2)	2.4	7.6	4.9	22	8.5

1) according to German DIN

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

3) Analyses data sheet provided by LUFA

4) data taken from Gawlik and Muntau, Eurosoils II Laboratory and Reference Materials for Soil-related    Studies, Environment Institute 1999

5) actual certified value on the corresponding soil certificate

Results Tier 1

During experiments in tier 1 test item control samples (the test item dissolved in soil eluates of LUFA 2.2 and LUFA 2.4) showed that the test item is stable in the aqueous phase and no indication for adsorption to the test vessel takes place. As matrix effects were observed during analyses, matrix-matched standards were prepared.

The parental mass balance for the test item was determined in the LUFA soils 2.2 and 2.4 with an application concentration of 5 mg/L, a soil / solution ratio of 1:100 and over an agitation time of 4 h. The parental mass balances were finally calculated by taking into account the test item recovery in the aqueous phase, the soil and residual test item in pore water. Mass balances below 90% were obtained. Therefore, the direct method was used throughout tier 2 and tier 3.

Results Tier 2 – Adsorption Kinetics

These experiments confirmed the results of tier 1. The test item was highly adsorptive and the adsorption equilibrium was determined after 2 h agitation. Results are shown in Table 2 below.

 

Table2:   Summarized Endpoints for the Components of PU-2018-821

Mobility according to McCall et al. (1980):K_OC 0 – 50 very high, K_OC 50 – 150 high, K_OC 150 – 500 medium, K_OC 500 – 2000 low, K_OC 2000 – 5000 slight, K_OC > 5000 immobile; based on results of tier 2

Soil Type	Kd[mL/g]	KOC[mL/g]	Mobility according to McCall et al.
BAPDETA
LUFA 2.1	782	108956	immobile
LUFA 2.2	2658	180810	immobile
LUFA 2.3	2181	529473	immobile
LUFA 2.4	3869	209160	immobile
Eurosoil 3	2193	70300	immobile
TAPDETA
LUFA 2.1	1304	181555	immobile
LUFA 2.2	2605	177242	immobile
LUFA 2.3	2283	554042	immobile
LUFA 2.4	3792	204979	immobile
Eurosoil 3	2188	70131	immobile
APDETA
LUFA 2.1	75	10477	immobile
LUFA 2.2	1068	72663	immobile
LUFA 2.3	1612	391310	immobile
LUFA 2.4	3470	187593	immobile
Eurosoil 3	3139	100606	immobile
PU-2018-821^1
LUFA 2.1	868	120933	immobile
LUFA 2.2	2540	172808	immobile
LUFA 2.3	2170	526648	immobile
LUFA 2.4	3823	206683	immobile
Eurosoil 3	2254	72245	immobile

1       =       Weighted mean value of both analysed components, content of components taken into account

Results Tier 3

Results Tier 3 – Desorption Kinetics and Desorption Isotherms

Only in LUFA 2.1, significant desorption (for APDETA) was observed during desorption kinetics. Therefore, only this soil was used for desorption isotherm experiments. The determined desorption isotherm did not show a linear trend.

Results Tier 3 – Adsorption Isotherms

As the adsorption was high (> 90%, except for LUFA 2.1 APDETA) in tier 2, the measured concentration in the lower applied concentrations were expected to be below the lowest calibration level in the aqueous phase during adsorption isotherm analysis. However, the concentrations were unexpected high in some measurements, which is not plausible if a linear correlation between concentration and adsorption is assumed. But as the test item control samples with a nominal concentration of 0.500 mg test item /L showed good recoveries, spiking and analytical method were verified.

In addition, the measured test item concentration in higher concentrations did not show a linear correlation either. The mass balances, moreover, indicate a reduced extraction efficiency in higher concentrations. If measured values were below the lowest calibration standards, these values were approximated from adsorption in tier 2. As 1/n of the linear Freundlich isotherm is expected to be in the range of 0.7 to < 1.0 and r2 > 0.975 indicates the applicability of the linear isotherm, it is obvious that the Freundlich model is not valid for the test item PU-2018-821 in the tested concentration range.

Individual values for K_d and K_OC were calculated for each soil and each concentration. But due to above described limitations for the applicability of the Freundlich model, it is recommended to use the results of tier 2 for risk assessment.