Poly(oxy-1,2-ethanediyl), α-[2-(dide- cylmethylammonio)ethyl]- .omega.- hydroxy-, propanoate (salt) (Bardap 26)

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:

1988-06-21 - 1989-12-29

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Remarks:

Study was conducted in accordance with the guidelines (U.S. EPA-FIFRA N-163-1 40 CFR, sec. 158.130 and 158.50), compliant with GLP and no deviations.

Qualifier:

according to guideline

Guideline:

other: U.S. EPA-FIFRA Guideline N-163-1

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: 40 CFR, Sec. 158.130 and 158.50

Deviations:

no

Principles of method if other than guideline:

Not applicable.

GLP compliance:

yes

Type of method:

batch equilibrium method

Media:

soil

Radiolabelling:

yes

Test temperature:

25 ºC +/-1ºC

Details on study design: HPLC method:

No information provided.

Analytical monitoring:

not specified

Details on sampling:

Adsorption: One-gram samples of each soil were placed into sterile, tared nalgene bottles. Triplicate aliquots (200 ml) of each standard solution were added to bottles to achieve nominal concentrations of 0.0, 0.70, 3.50, 5.25 and 7.00 µg/ml. Soil suspensions were shaken in a dark environmentally controlled chamber at 25+/-1 ºC for 24 hours. Suspensions were then centrifuged (2000 rpm/15 minutes) and supernatants and soil were separated. Before removing the supernatant, the equilibrium pH was measured using a suitable pH meter.

Desorption: Appropriate aliquots of fresh 0.01M CaCl2 solution were added to each sample according to the volume removed after the adsorption phase. The soil suspensions were shaken for 24 hours in a dark environmentally controlled chamber at 25+/-1 ºC. Suspensions were then centrifuged (2000 rpm/15 minutes) and supernatants and soil were separated. The 7.00 µg/ml samples were subject to two further desorption cycles.

Details on matrix:

Soil types used were sand, sandy loam, silty clay loam, and silt loam. The soil:water ratio was 1:200 soil:water.

Soil #92 Sand, Northwood, ND
% Organic matter = 0.5
% Sand = 92
% Silt = 4
% Clay = 4
Cation exchange capacity meq/100g = 0.3
pH = 7.4
Field capacity at 1/3 Bar Percent = 1.87
Bulk density gm/cm3 = 1.64

Soil #93 Sandy Loam, Northwood, ND
% Organic matter = 1.8
% Sand = 78
% Silt = 10
% Clay = 12
Cation exchange capacity meq/100g = 0.7
pH = 6.3
Field capacity at 1/3 Bar Percent = 14.41
Bulk density gm/cm3 = 1.23

Soil #91 Silty Clay Loam, Northwood, ND
% Organic matter = 4.1
% Sand = 16
% Silt = 52
% Clay = 32
Cation exchange capacity meq/100g = 32.3
pH = 7.9
Field capacity at 1/3 Bar Percent = 35.92
Bulk density gm/cm3 = 1.10

Soil #90 Silt Loam, Northwood, ND
% Organic matter = 4.2
% Sand = 24
% Silt = 52
% Clay = 24
Cation exchange capacity meq/100g = 22.7
pH = 7.4
Field capacity at 1/3 Bar Percent = 35.92
Bulk density gm/cm3 = 1.08

Details on test conditions:

The conditions for the definitive test were selected based on the results from two preliminary tests. From these tests, the test material was shown to be stable in the soil/solution mixture for at least 24 hours. The desired 20-80% adsorbed range could not be obtained with the preliminary 1:10 or 1:50 soil to solution ratio, a ratio of 1:200 (soil to solution) was selected for the definitive study. Results from a nalgene adsorption test demonstrated that DDAC did not adsorb to the nalgene test containers.

Nominal concentrations: 0.0, 0.70, 3.50, 5.25, 7.00 µg/ml
Measured concentrations (LSC analysis): 0.0, 0.665, 3.69, 5.36, 7.40 µg/ml
The definitive soil adsorption/desorption study was conducted at 25+/-1ºC in the dark with DDAC and four soils (1 x sand, 1 x sandy loam, 1 x silty clay loam and 1 x silt loam).
The definitive study was conducted at a 1:200 soil to water ratio, and an equilibrium time of 24 hours was used.

For adsorption, one-gram samples of soil were placed into sterile Nalgene bottles; triplicate aliquots of each standard solution were added to the Nalgene bottles. Soil suspensions were shaken in dark environmental chamber at 25 ºC for 24 hours.
For desorption, soil samples from the adsorption phase were shaken with 0.01 m CaCl2 for 24 hours in dark environmental chamber at 25 ºC. Suspensions were then centrifuged and supernatants and soil were separated.

Sample No.:

#1

Duration:

24 h

Initial conc. measured:

>= 0.7 - <= 7 mg/kg soil d.w.

Temp.:

25 °C

Sample No.:

#2

Duration:

24 h

Initial conc. measured:

>= 0.7 - <= 7 mg/kg soil d.w.

Temp.:

25 °C

Sample No.:

#3

Duration:

24 h

Initial conc. measured:

>= 0.7 - <= 7 mg/kg soil d.w.

Temp.:

25 °C

Sample No.:

#4

Duration:

24 h

Initial conc. measured:

>= 0.7 - <= 7 mg/kg soil d.w.

Temp.:

25 °C

Sample no.:

#1

Duration:

24 h

Sample no.:

#2

Duration:

24 h

Sample no.:

#3

Duration:

24 h

Sample no.:

#4

Duration:

24 h

Computational methods:

No information provided.

Key result

Sample No.:

#1

Type:

Koc

Value:

437 805 dimensionless

Temp.:

25 °C

Matrix:

sand

% Org. carbon:

0.25

Remarks on result:

other: sample #92

Sample No.:

#2

Type:

Koc

Value:

908 757 dimensionless

Temp.:

25 °C

Matrix:

Sandy loam

% Org. carbon:

0.9

Remarks on result:

other: sample #93

Sample No.:

#3

Type:

Koc

Value:

1 599 564 dimensionless

Temp.:

25 °C

Matrix:

Silty clay loam

% Org. carbon:

2.05

Remarks on result:

other: sample #91

Sample No.:

#4

Type:

Koc

Value:

1 469 081 dimensionless

Temp.:

25 °C

Matrix:

Silt loam

% Org. carbon:

2.1

Remarks on result:

other: sample #90

Phase system:

other: Koc

Type:

other: Koc

Value:

1 599 564

Remarks on result:

other: Adsorption phase in #91 silty clay loam

Phase system:

other: Koc

Type:

other: Koc

Value:

1 469 081

Remarks on result:

other: Adsorption phase in #90 silt loam

Phase system:

other: Koc

Type:

other: Koc

Value:

236 473

Remarks on result:

other: Mobility coefficient desorption phase in #92 sand

Phase system:

other: Koc

Type:

other: Koc

Value:

230 498

Remarks on result:

other: Mobility coefficient desorption phase in #93 sandy loam

Phase system:

other: Koc

Type:

other: Koc

Value:

405 328

Remarks on result:

other: Mobility coefficient desorption phase in #91 silty clay loam

Phase system:

other: Koc

Type:

other: Koc

Value:

367 334

Remarks on result:

other: Mobility coefficient desorption phase in #90 silt loam

Details on results (HPLC method):

No information provided.

Adsorption and desorption constants:

No information provided.

Recovery of test material:

Mass balance of DDAC (% of total) ranged from 80.81 to 117.99%

Concentration of test substance at end of adsorption equilibration period:

Soil Type Mean Mean Mean
Percent Adsorbed Percent Desorbed Mass Balance
#92 Sand 96.0 18.2 101%
#93 Sandy Loam 96.2 2.93 106%
#91 Silty Clay Loam 99.2 1.90 92.6%
#90 Silt Loam 99.0 1.34 105%

Concentration of test substance at end of desorption equilibration period:

Refer to section 'Concentration of test substance at end of adsorption equilibrium period' above.

Sample no.:

#1

Duration:

24 h

% Adsorption:

>= 80.45 - <= 92.86

Sample no.:

#2

Duration:

24 h

% Adsorption:

>= 94.35 - <= 98.42

Sample no.:

#3

Duration:

24 h

% Adsorption:

>= 99.09 - <= 99.71

Sample no.:

#4

Duration:

24 h

% Adsorption:

>= 99.22 - <= 99.39

Sample no.:

#1

Duration:

24 h

% Desorption:

>= 16.26 - <= 39.33

Sample no.:

#2

Duration:

24 h

% Desorption:

>= 2.2 - <= 12.6

Sample no.:

#3

Duration:

24 h

% Desorption:

>= 0.2 - <= 1.4

Sample no.:

#4

Duration:

24 h

% Desorption:

>= 0.2 - <= 1.66

Transformation products:

not specified

Details on results (Batch equilibrium method):

No information provided.

Statistics:

No information provided.

Sand had the lowest adsorption and desorption coefficients and adsorption phase mobility coefficient. loam had the lowest desorption phase mobility coefficient. Silty clay loam had the highest coefficients.

Adsorption and desorption coefficients.

Soil type	Adsorption coefficient (Kd)	Desorption coefficient (Kd)	Mobility coefficient (adsorption phase) (Koc)	Mobillity coefficient (desorption phase) (Koc)
Sand	1,095	591	437,805	236,473
Sandyloam	8,179	2,074	908,757	230,498
Silty clay loam	32,791	8,309	1,599,564	405,328
Silt loam	30,851	7,714	1,469,081	367,334

Due to the immobility of DDAC, the percent adsorbed was not in the range 20 -80% which the Freundlich model typically describes the sorption characteristics of a compound. However, isotherms were determined with the correlation coefficents ranging from 0.9265 to 0.9970 for adsorption which implies that the data adequately fits the Freundlich model. Correlation coefficients for the desorption isotherms ranged from 0.8515 to 0.9361, therefore the isotherm determined, the Freundlich constants Kd and n, and the adsorption constants Koc based on the organic carbon content obtained from these were reported.

Validity criteria fulfilled:

yes

Conclusions:

Didecyldimethylammonium Chloride has little or no potential for mobility in soil and should not pose an environmental risk for contamination of groundwater, under the conditions of this study.

Executive summary:

In a study conducted in accordance with U.S.EPA-FIFRA Guideline N-163-1, aqueous¹⁴C-Didecyldimethylammonium Chloride (DDAC) was equilibrated with four soil types (sand, sandy loam, silty clay loam and silt loam) and adsorption and desorption coefficients and constants were determined. Initial test concentrations of the compound were 0.0, 0.70, 3.50, 5.35, 7.00 µg/ml. One-gram samples of soil were placed into sterile Nalgene bottles; triplicate aliquots of each standard solution were added to the Nalgene bottles. Soil suspensions were shaken in dark environmental chamber at 25 ºC for 24 hours. Suspensions were then centrifuged and supernatants and soil were separated. Soil samples from the adsorption phase were shaken with 0.01 m CaCl₂for 24 hours in dark environmental chamber at 25 ºC. Suspensions were then centrifuged and supernatants and soil were separated. Sand samples were extracted with DMF-acetic acid for radioanalysis; all other soil types were combusted for radioanalysis. Sand had the lowest adsorption and desorption coefficients and adsorption phase mobility coefficient. loam had the lowest desorption phase mobility coefficient. Silty clay loam had the highest coefficients.Didecyldimethylammonium Chloride has little or no potential for mobility in soil and should not pose an environmental risk for contamination of groundwater, under the conditions of this study.

Description of key information

One key study is available, conducted in accordance with U.S.EPA-FIFRA Guideline N-163-1, with aqueous 14C-Didecyldimethylammonium Chloride (DDAC) as the test substance.  

Additional information

Key study:

In a study conducted in accordance with U.S.EPA-FIFRA Guideline N-163-1, aqueous ¹⁴C-Didecyldimethylammonium Chloride (DDAC) was equilibrated with four soil types (sand, sandy loam, silty clay loam and silt loam) and adsorption and desorption coefficients and constants were determined. Initial test concentrations of the compound were 0.0, 0.70, 3.50, 5.35, 7.00 µg/ml. One-gram samples of soil were placed into sterile Nalgene bottles; triplicate aliquots of each standard solution were added to the Nalgene bottles. Soil suspensions were shaken in dark environmental chamber at 25ºC for 24 hours. Suspensions were then centrifuged and supernatants and soil were separated. Soil samples from the adsorption phase were shaken with 0.01 m CaCl₂ for 24 hours in dark environmental chamber at 25ºC. Suspensions were then centrifuged and supernatants and soil were separated. Sand samples were extracted with DMF-acetic acid for radioanalysis; all other soil types were combusted for radioanalysis. Sand had the lowest adsorption and desorption coefficients and adsorption phase mobility coefficient. loam had the lowest desorption phase mobility coefficient. Silty clay loam had the highest coefficients.Didecyldimethylammonium Chloride has little or no potential for mobility in soil and should not pose an environmental risk for contamination of groundwater, under the conditions of this study.

Overall Summary:

A study to determine adsorption and desorption in soil for N,N-Didecyl-N-methyl-poly(oxyethyl)ammonium Propionate was not carried out as an adequate study has been conducted on the chemical and structural analog, Didecyldimethylammonium Chloride. In view of the chemical and structural similarities, it is considered that the available data is adequate for N,N-Didecyl-N-methyl-poly(oxyethyl)ammonium Propionate.

Didecyldimethylammonium Chloride was classified as immobile in four soil/sediment types with the adsorption (K_d) and mobility (K_oc) coefficients of K_d=1,095 and K_oc=437,805 for sand, K_d=8,179 and K_oc=908,757 for sandy loam, K_d=32,791 and K_oc=1,599,564 for clay loam, and K_d=30,851 and K_oc=1,469,081 for silt loam (Ref No 1792).

The results of the adsorption in soil study on a structural analog Didecyldimethylammonium chloride indicate little or no potential for mobility in soil and should not pose an environmental risk for contamination of ground water. Thus, it is considered that a short or a long-term Mobility- Lysimeter study is not justified.