N-[3-(dimethylamino)propyl]stearamide monoacetate

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2015-05-11 to 2015-11-02

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2000

GLP compliance:

yes (incl. QA statement)

Type of method:

batch equilibrium method

Media:

soil

Test temperature:

NS

Details on study design: HPLC method:

NA

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 100 mg/L
- Sampling interval: after 2, 4 and 6 h contact time.
- Sample storage before analysis:NS

Matrix no.:

#1

Matrix type:

loam

% Org. carbon:

6.54

pH:

7.28

CEC:

28.87 other: cool/kg

Matrix no.:

#2

Matrix type:

silt loam

% Org. carbon:

1.36

pH:

4.6

CEC:

11.53

Matrix no.:

#3

Matrix type:

silty clay loam

% Org. carbon:

5.36

pH:

6.81

CEC:

22.9

Matrix no.:

#4

Matrix type:

silt loam

% Org. carbon:

1.39

pH:

7.84

CEC:

7.08

Matrix no.:

#5

Matrix type:

silt loam

% Org. carbon:

6.85

pH:

7.96

CEC:

22.13

Details on matrix:

COLLECTION AND STORAGE
- Geographic location: Jilin 125.73 degrees E 42.28 degrees North; Jiangxi 117.01 degrees E 28.23 degrees N; Jiangsu 120.30 degrees E 31.60 degrees N; Shandong 116.06 degrees E 34.81 degrees N; Gansu 100.40 degrees E 38.90 degrees N. (Soil information can be seen in table in the Any other information on materials and methods incl. tables section)
- Collection procedures: NS
- Sampling depth (cm): NS
- Storage conditions:
- Storage length:
- Soil preparation (e.g.: 2 mm sieved; air dried etc.): soils were air dried at 20-25 degrees Celsius and sieved to particle size 0.3 mm.

PROPERTIES
- % sand: NS
- % silt: NS
- % clay: NS
- pH: See above
- Organic carbon (%): See above
- CEC (meq/100 g): See above
- Carbonate as CaCO3:NS
- Insoluble carbonates (%):NS
- Extractable Cations (Ca, Mg, Na, K, H) (MEQ/100 g): NS
- Special chemical/mineralogical features:NS
- Clay fraction mineralogy: NS
- Moisture at 1/3 atm (%): NS
- Bulk density (g/cm3): NS
- Biomass (e.g. in mg microbial C/100 mg, CFU or other): NS

Details on test conditions:

TEST CONDITIONS
- Buffer: water
- pH: NS
- Suspended solids concentration: NS


TEST SYSTEM
- Type, size and further details on reaction vessel:NS
- Water filtered (i.e. yes/no; type of size of filter used, if any): deionised water
- Amount of soil/sediment/sludge and water per treatment (if simulation test): 100 ml aqueous phase, 1 g soil
- Soil/sediment/sludge-water ratio (if simulation test): 1:100 soil/solution
- Number of reaction vessels/concentration: NS
- Measuring equipment: HPLC-MS/MS
- Test performed in closed vessels due to significant volatility of test substance: No
- Method of preparation of test solution: test substance was dissolved in deionised water (1.0417 g test substance in 100 mL water)
- Are the residues from the adsorption phase used for desorption: no

Sample No.:

#5

Duration:

6 h

Initial conc. measured:

100 other: mg/L

Sample No.:

#4

Duration:

6 h

Initial conc. measured:

100 other: mg/L

Sample No.:

#3

Duration:

6 h

Initial conc. measured:

100 other: mg/L

Sample No.:

#1

Duration:

6 h

Initial conc. measured:

100 other: mg/L

Sample No.:

#2

Duration:

6 h

Initial conc. measured:

100 other: mg/L

Sample no.:

#1

Duration:

6 h

Conc. of adsorbed test mat.:

100 other: mg/L

Sample no.:

#2

Duration:

6 h

Conc. of adsorbed test mat.:

100 other: mg/L

Sample no.:

#3

Duration:

6 h

Conc. of adsorbed test mat.:

100 other: mg/L

Sample no.:

#4

Duration:

6 h

Conc. of adsorbed test mat.:

100 other: mg/L

Sample no.:

#5

Duration:

6 h

Conc. of adsorbed test mat.:

100 other: mg/L

Key result

Sample No.:

#5

Type:

Kd

Value:

9 070 L/kg

pH:

6.85

% Org. carbon:

6.85

Key result

Sample No.:

#4

Type:

Kd

Value:

35 900 L/kg

pH:

7.84

% Org. carbon:

1.39

Key result

Sample No.:

#3

Type:

Kd

Value:

19 500 L/kg

pH:

6.81

% Org. carbon:

5.36

Key result

Sample No.:

#2

Type:

Kd

Value:

2 550 L/kg

pH:

4.6

% Org. carbon:

1.36

Key result

Sample No.:

#1

Type:

Kd

Value:

57 700 L/kg

pH:

7.28

% Org. carbon:

6.54

Adsorption and desorption constants:

Kd: 5.77x10^4, 2.55x10^3,1.95x10^4,3.59x10^4 and 9.07x10^3, soils A to E, respectively

Concentration of test substance at end of desorption equilibration period:

After 48 h (soil/solution ratio 1:100, conc. 100 mg/l) the test substance was not detected in the water phase in either soil test.

Sample no.:

#1

Duration:

6 h

% Adsorption:

73.5

Remarks on result:

other: Percent recovery of mass balance (percent adsorption not applicable here)

Sample no.:

#2

Duration:

6 h

% Adsorption:

76.5

Remarks on result:

other: Percent recovery of mass balance (percent adsorption not applicable here)

Sample no.:

#3

Duration:

6 h

% Adsorption:

74.5

Remarks on result:

other: Percent recovery of mass balance (percent adsorption not applicable here)

Sample no.:

#4

Duration:

6 h

% Adsorption:

81

Remarks on result:

other: Percent recovery of mass balance (percent adsorption not applicable here)

Sample no.:

#5

Duration:

6 h

% Adsorption:

84.5

Remarks on result:

other: Percent recovery of mass balance (percent adsorption not applicable here)

Details on results (Batch equilibrium method):

The results can be seen in Table 1. in the "Any other information on results incl. tables" section

Table 1. Results of adsorbtion kinetics

Time (h)	Percentage of adsorption (%) in soil types
	A	B	C	D	E
2	99.47	99.93	99.84	99.89	99.68
4	99.60	99.86	99.90	99.94	99.73
6	99.56	99.90	99.87	99.93	99.72
Kd (cm^3/g)	5.77 x 10^4	2.55x10^3	1.95x10^4	3.59x10^4	9.07x10^3
Koc (cm^3/g	8.83x10^4	1.88x10^6	3.64x10^5	2.58x10^6	1.32x10^5

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficient (Kd) values of the test substance in five different soils were 5.77x10^4, 2.55x10^3,1.95x10^4,3.59x10^4 and 9.07x10^3, respectively. The corresponding Koc values were: 8.83x10^4, 1.88x10^6, 3.64x10^5,2.58x10^6 and 1.32x10^5 cm^3/g respectively.
The test substance was not detected in the water phase fo the five soils (<0.01 mg/L).

Executive summary:

This test was carried out according to "The guidelines for testing of chemicals" (HJ/T 153-2004) with reference to OECD guideline 106 "Adsorption - Desorption Using a Batch Equilibrium Method" (2000). Five soil types with different pH, texture and organic carbon content sampled from five provinces in China were selected. The batch equilibrium method was used and Tier 1 to 5 tests were performed to establish the adsorption characteristics of the test substance. 

The results showed that the optimal soil/aqueous ratio for the five soils is 1:100 and the appropriate adsorption equilibrium time is 6 hours. 

Anion and cation of the substance was produced in water and the cation form was measured by HPLC-MS/MS. It contains a long straight chain structure which is readily adsorbed by soil. The test substance was almost completely adsorbed on the soils. 

The adsorption coefficient (K_d) values of the test substance in the five soils were 5.77x10⁴, 2.55x10³,1.95x10⁴,3.59x10⁴ and 9.07x10³, respectively. The corresponding K_oc values were: 8.83x10⁴, 1.88x10⁶, 3.64x10⁵,2.58x10⁶ and 1.32x10⁵ cm³ g^-1 respectively.

The test substance was not detected in the water phase of the five soils (<0.01 mg/L), there was no detectable desorption.

Description of key information

Koc = 2,580,000 L/kg; OECD 106; Shenhu, S. (2015)

Key value for chemical safety assessment

Koc at 20 °C:

2 580 000

Additional information

This key study was carried out according to "The guidelines for testing of chemicals" (HJ/T 153-2004) with reference to OECD guideline 106 "Adsorption - Desorption Using a Batch Equilibrium Method" (2000). Five soil types with different pH, texture and organic carbon content sampled from five provinces in China were selected. The batch equilibrium method was used and Tier 1 to 5 tests were performed to establish the adsorption characteristics of the test substance. 

The results showed that the optimal soil/aqueous ratio for the five soils is 1:100 and the appropriate adsorption equilibrium time is 6 hours. 

Anion and cation of the substance was produced in water and the cation form was measured by HPLC-MS/MS. It contains a long straight chain structure which is readily adsorbed by soil. The test substance was almost completely adsorbed on the soils. 

The adsorption coefficient (K_d) values of the test substance in the five soils were 5.77x10⁴, 2.55x10³,1.95x10⁴,3.59x10⁴ and 9.07x10³, respectively. The corresponding K_oc values were: 8.83x10⁴, 1.88x10⁶, 3.64x10⁵,2.58x10⁶ and 1.32x10⁵ cm³ g^-1 respectively.

The test substance was not detected in the water phase of the five soils (<0.01 mg/L), there was no detectable desorption.