1-ethyl-3-methyl-3H-imidazolium dicyanidoamide(1-)

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: OECD guidelines for testing of chemicals, Test guideline 106: Adsorption/desorption using a batch equilibrium method, 2000, Paris, OECD.

GLP compliance:

no

Remarks:

this research was conducted for academic purposes and was not therefore not GLP-compliant. Nonetheless, the study is acceptable for assessment.

Type of method:

batch equilibrium method

Media:

soil

Specific details on test material used for the study:

- Name of test material (as cited in publication): 1-butyl-3-methyl-imidazolium tetrafluoroborate
- Supplier: Merck KGaA (Darmstadt, Germany)

Radiolabelling:

no

Test temperature:

20 °C

Analytical monitoring:

yes

Details on sampling:

All test concentrations were sampled after 24 h incubation with the soil.

Matrix no.:

#1

Matrix type:

loamy sand

% Clay:

7.5

% Sand:

>= 5.4 - <= 5.8

% Org. carbon:

2.3

Matrix no.:

#2

Matrix type:

other: loamy sand; kaolinite added

% Clay:

10

% Sand:

>= 5.4 - <= 5.8

% Org. carbon:

2.3

Matrix no.:

#3

Matrix type:

other: loamy sand; kaolinite added

% Clay:

15

% Sand:

>= 5.4 - <= 5.8

% Org. carbon:

2.3

Matrix no.:

#4

Matrix type:

other: loamy sand; smectite added

% Clay:

10

% Sand:

>= 5.4 - <= 5.8

% Org. carbon:

2.3

Matrix no.:

#5

Matrix type:

other: loamy sand; smectite added

% Clay:

15

% Sand:

>= 5.4 - <= 5.8

% Org. carbon:

2.3

Matrix no.:

#6

Matrix type:

other: loamy sand, OM wt5%

% Clay:

10

% Sand:

>= 5.4 - <= 5.8

% Org. carbon:

2.3

Matrix no.:

#7

Matrix type:

other: loamy sand OM 10 wt%

% Clay:

15

% Sand:

>= 5.4 - <= 5.8

% Org. carbon:

2.3

Details on matrix:

- Standard soil: LUFA 2.2
- Source: Landwirtschaftliche Untersuchungs- und Forschungsanstalt Speyer (Speyer, Germany).
- Other: LUFA 2.2 was supplemented with minerals to obtain soils with different clay concentrations. Furthermore, flower soil was added to obtain dry matter contents of 5 and 10 wt%.

Details on test conditions:

TEST CONDITIONS
- Test concentrations: 4500, 1000, 450, 100, 45 and 10 µmol/L
- Soil/water ratio: 1:2
- Shaking: at 150 rpm for 24h at 25 °C in darkness

TEST SYSTEM
- Method of preparation of test solution: ionic solutions were prepared in 0.01 M CaCl2

Sample No.:

#1

Type:

other: Kf

Value:

3.6 L/kg

Remarks on result:

other: n = 0.724; r2 = 0.973

Sample No.:

#2

Type:

other: Kf

Value:

3.3 L/kg

Remarks on result:

other: n = 0.769; r2 = 0.972

Sample No.:

#3

Type:

other: Kf

Value:

218.2 L/kg

Remarks on result:

other: n = 0.337; r2 = 0.992

Sample No.:

#4

Type:

other: Kf

Remarks on result:

not determinable

Sample No.:

#5

Type:

other: Kf

Value:

10.3 L/kg

Remarks on result:

other: n = 0.969; r2 = 0.994

Sample No.:

#6

Type:

other: Kf

Value:

21.1 L/kg

Remarks on result:

other: n = 0.337; r2 = 0.992

Adsorption and desorption constants:

With decreasing substance concentrations the sorption increased. The addition of organic matter and clay increases sorption. Addition of smectite showed the biggest effects on the sorption capacity. See 'Any other information on results incl. tables'.

Table: Determined Kf-values and re-calculated Koc-values

Sample	Note	Kf-values	%Org carbon	Koc-values
Lufa 2.2		3.6	2.3	157
Lufa with 10% clay	Kaolinite added	3.3	2.3	143
Lufa with 15% clay	Kaolinite added	1.6	2.3	69
Lufa with 10% clay	Smectite added	218.2	2.3	9487
Lufa with 15% clay	Smectite added	n.d.	2.3	-
Lufa with 5% Corg		10.3	2.3	448
Lufa with 10% Corg		21.1	2.3	917

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: OECD (2000) OECD Guideline for testing of chemicals 106. OECD, Paris

GLP compliance:

no

Remarks:

this research was conducted for academic purposes and was not therefore not GLP-compliant. Nonetheless, the study is acceptable for assessment.

Type of method:

batch equilibrium method

Media:

soil

Specific details on test material used for the study:

- Name of test material (as published): 1-ethyl (EMIM) methylimidazolium (chloride)
- Purity: ≥ 98%
- Supplier: Merck KGaA (Darmstadt, Germany)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 10 (0.1 - 3 mM)
- Sampling interval: after 24 hours

Matrix no.:

#1

Matrix type:

other: Alluvial agricultural soil

% Clay:

60.5

% Org. carbon:

3.2

pH:

6.6

CEC:

298 other: meq/g

Matrix no.:

#2

Matrix type:

other: Podsolic soil

% Clay:

28.2

% Org. carbon:

2.3

pH:

4.3

CEC:

48 other: meq/g

Matrix no.:

#3

Matrix type:

other: Sandy - clayey silt

% Clay:

94

% Org. carbon:

12.5

pH:

5.3

CEC:

270 other: meq/g

Matrix no.:

#4

Matrix type:

other: Glacial till

% Clay:

62.3

% Org. carbon:

0.89

pH:

7.7

CEC:

64 other: meq/g

Matrix no.:

#5

Matrix type:

other: Beach sand

% Clay:

0.17

% Org. carbon:

0.081

pH:

7.6

CEC:

30 other: meq/g

Details on matrix:

SOIL 1
- Name: Alluvial agricultural soil
- Sampling area: Kiezmark - 20 km east from Gdańsk
- Stratigraphy: Recent (Holocene subsoil)
- pH: 6.6
- OM [%]: 5.5
- CEC [meqg-1]: 298
- Clay fraction [%]: 60.5

SOIL 2
- Name: Podsolic soil
- Sampling area: Trójmiejski Landscape Park - northwestern part of Gdynia
- Stratigraphy: Recent (Pleistocene subsoil)
- pH: 4.3
- OM [%]: 3.9
- CEC [meqg-1]: 48
- Clay fraction [%]: 28.2

SOIL 3A
- Name: Sandy–clayey silt
- Sampling area: Orłowo Cliff - Gdynia
- Stratigraphy: Neogene–Miocene
- pH: 5.3
- OM [%]: 21.5
- CEC [meqg-1]: 270
- Clay fraction [%]: 94.0

SOIL 3B
- Name: Glacial till
- Sampling area: Orłowo Cliff—Gdynia
- Stratigraphy: Pleistocene–Middle Polish; Glaciation–Warthanian
- pH: 7.7
- OM [%]: 1.54
- CEC [meqg-1]: 64
- Clay fraction [%]: 62.3

SOIL 3C
- Name: Beach sand
- Sampling area: Orłowo - Gdynia
- Stratigraphy: Recent
- pH: 7.6
- OM [%]: 0.14
- CEC [meqg-1]: 30
- Clay fraction [%]: 0.17

Details on test conditions:

TEST CONDITIONS
- Replicates: 3
- pH: varied (dependent on soil-type)
- Agitation time: 24 hours

TEST SYSTEM
- Method of preparation of test solution: ionic solutions were prepared in 0.01 M CaCl2
- Other: the aqueous phase was recovered as completely as possible, supernatant was analyzed right after

Remarks on result:

other: see 'Any other information on results incl. tables'

Adsorption and desorption constants:

See 'Any other information on results incl. tables'. The majority of Koc-values was <100 L/kg. The higher Koc-values were determined in samples containing only small amounts of organic matter.

Transformation products:

not measured

Statistics:

Calculations were performed according to Folk and Ward Method (1957).

Table: Sorption coefficients and organic carbon adsorption coefficients (Koc-values).

Sample	Note	Kd-values	%Org carbon	Koc-values*
Alluvial agricultural soil (#1)	First layer	3.3	3.2	103
	Second layer	2.3	3.2	72
Podsolic soil (#2)	First layer	1.7	2.3	75
	Second layer	0.7	2.3	31
Sandy-clayey silt (#3)	First layer	2.5	12.5	20
	Second layer	1.3	12.5	10
Glacial till (#4)	First layer	2.8	0.9	313
	Second layer	2	0.9	224
Beach sand (#5)	First layer	1.2	0.1	1478
	Second layer	0.5	0.1	616

*The respective Koc values were calculated from the available Kd values, as in accordance with OECD 106, paragraph 86.

Reference 3

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: OECD, 2000. OECD Guideline for testing of chemicals. In: OECD (Ed.). 106.

GLP compliance:

no

Remarks:

this research was conducted for academic purposes and was not therefore not GLP-compliant. Nonetheless, the study is acceptable for assessment.

Type of method:

batch equilibrium method

Media:

soil

Specific details on test material used for the study:

- Name of test material (as published): 1-ethyl (EMIM) methylimidazolium (chloride)
- Purity: ≥ 98%
- Supplier: Merck KGaA (Darmstadt, Germany)

Radiolabelling:

no

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 17 (0.1 - 500 mM)
- Sampling interval: after 24 hours

Matrix no.:

#1

Matrix type:

other: Agricultural chernozem

% Clay:

57.1

% Org. carbon:

11.9

pH:

7.2

CEC:

207 other: meq/g

Matrix no.:

#2

Matrix type:

other: Clayey brown soil

% Clay:

69.3

% Org. carbon:

3.5

pH:

5.8

CEC:

99 other: meq/g

Matrix no.:

#3

Matrix type:

other: Alluvial agricultural soil

% Clay:

60.5

% Org. carbon:

3.2

pH:

6.6

CEC:

298 other: meq/g

Matrix no.:

#4

Matrix type:

other: Loessy Brown soil

% Clay:

47.4

% Org. carbon:

3.8

pH:

6.5

CEC:

78 other: meq/g

Matrix no.:

#5

Matrix type:

other: Acidic Brown soil

% Clay:

71.2

% Org. carbon:

4.4

pH:

5.2

CEC:

70 other: meq/g

Matrix no.:

#6

Matrix type:

other: Forest Podsolic soil

% Clay:

28.2

% Org. carbon:

2.3

pH:

4.3

CEC:

48 other: meq/g

Matrix no.:

#7

Matrix type:

other: Sandy Brown soil

% Clay:

73.8

% Org. carbon:

4.2

pH:

5.4

CEC:

100 other: meq/g

Matrix no.:

#8

Matrix type:

other: Loess soil

% Clay:

57.9

% Org. carbon:

2.7

pH:

5.3

CEC:

130 other: meq/g

Matrix no.:

#9

Matrix type:

other: Sandy - clayey silt

% Clay:

94

% Org. carbon:

12.5

pH:

5.3

CEC:

270 other: meq/g

Matrix no.:

#10

Matrix type:

other: Glacial till

% Clay:

62.3

% Org. carbon:

0.9

pH:

7.7

CEC:

64 other: meq/g

Matrix no.:

#11

Matrix type:

other: Beach sand

% Clay:

0.17

% Org. carbon:

0.081

pH:

7.6

CEC:

30 other: meq/g

Details on matrix:

- Organic matter contents (OM%) from matrix number 1 to 11: 20.5, 6.0, 5.5, 6.5, 7.5, 3.9, 7.3, 4.6, 21.5, 1.54 and 0.14%

Details on test conditions:

TEST CONDITIONS
- Replicates: 3
- Agitation time: 24 hours

TEST SYSTEM
- Method of preparation of test solution: ionic solutions were prepared in 0.01 M CaCl2
- Other: the aqueous phase was recovered as completely as possible, supernatant was analyzed right after

Remarks on result:

other: see 'Any other information on results incl. tables'

Adsorption and desorption constants:

See 'Any other information on results incl. tables'. The majority of Koc-values was <100 L/kg. The higher Koc-values were determined in samples containing only small amounts of organic matter.

Statistics:

Excel 2007 (Microsoft Corp., Seattle, USA) and Statistica 7.1 (Statsoft, Tulsa, USA) were used for interpretation. Testing on normality was performed with the Kolgomorov-Smirnov test.

Table: Sorption coefficients and organic carbon adsorption coefficients (Koc-values).

Sample	Kd-values	%Org carbon	Koc-values*
Agricultural chernozem (#1)	2.7	11.9	23
Clayey brown soil (#2)	2.6	3.5	75
Alluvial agricultural soil (#3)	2.3	3.2	72
Loessy Brown soil (#4)	2	3.8	53
Acidic Brown soil (#5)	1.9	4.4	44
Forest Podsolic soil (#6)	0.7	2.3	31
Sandy Brown soil (#7)	1.4	4.2	33
Loess soil (#8)	1.9	2.7	71
Sandy - clayey silt (#9)	1.3	12.5	10
Glacial till (#10)	2	0.9	224
Beach sand (#11)	0.5	0.1	616

*The respective Koc values were calculated from the available Kd values, as in accordance with OECD 106, paragraph 86.

Description of key information

The adsorption coefficient (Koc) is assumed to be 357 L/kg (log Koc = 2.55), as a conservative approach. Based on a log Koc of <3, adsorption is not expected.

Additional information

The adsorption / desorption potential of the substance is assessed in a weight-of-evidence approach, based on available literature. Several studies performed adsorption experiments with 1-methyl-3-ethylimidazolium and varying anionic moieties (either the inorganic chlorine or tetrafluoroborate).

Mrozik and colleagues investigated the adsorption potential of several ionic liquids, with a focus on alkylimidazoliums (Mrozik, 2009; Mrozik 2012). They determined the adsorption coefficient of 1-ethyl-3-methyl cyanocyanamide chloride in three soil types (study from 2009) and eleven soil types (study from 2012), using the batch-equilibrium technique (OECD 2000). Varying concentrations were used (0.1 - 0.3 mM and 0.1 - 500 mM, respectively). The mixtures were agitated for 24 hours, whereafter the concentration of substance was determined by analytical techniques from the recovered aqueous phase (supernatant). In the first study, the determined Kd's ranged from 1.2 - 3.3 L/kg for the first layer and 0.5 - 2.3 L/kg for the final concentration. In the second study, Kd's were determined to be in the range of 0.5 - 2.7 L/kg. These values were re-calculated (as in accordance with OECD 106) to Koc-values of which the majority of Koc-values was <100 L/kg. Higher Koc-values were determined in samples containing only small amounts of organic matter.

Matzke and colleagues (2008) also investigated the sorption and desorption potential of imidazolium based ionic liquids in different soil types. They determined the adsorption potential of 1-butyl-3-methyl-imidazolium tetrafluoroborate. In this study, performed according to OECD 2000, standard LUFA 2.2 soil was used as basis. Furthermore, the authors varied with clay content (either by addition of kaolinite or smectite) and organic matter for different test conditions. In total, ten different concentrations were analyzed (10, 45, 100, 450, 1000 and 4500 µmol/L). After 24 hours of incubation at 20 °C in the dark on a shaker, the aqueous phase was extracted from the soil after which the test concentrations were determined with a HPLC. Kf values (Freundlich coefficient) were determined to be in the range of 3.3 - 218.2, depending on the composition of the soil.

In conclusion, the majority of organic carbon adsorption coefficients were determined to be well below <100 L/kg. As a worst-case approach, a Koc-value of 357 L/kg will be used for the risk assessment.

INORGANIC MOIETY

The effect of the inorganic moiety Dicyanamide (CAS 504-66-5) on adsorption does not need to be regarded. As shown in the presented data, similar adsorption behaviour is observed, regardless of the anion present. Therefore, the assessment is based solely on the data available for 1-Methyl-3-ethylimidazolium (CAS 65039-03-4).