N,N-bis(2-hydroxyethyl)-3-[(C16-18)alkoxy]-1-propanamine

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:

20 October 1995 - 21 Decemeber 1995

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1993

Deviations:

yes

Remarks:

Soils were dried for 24 hours at 110 degrees Celsius, not 12 hours at 100 degrees Celsius. The soils and water were tumbled for 2 hours instead of 24 hours. These deviations are not believed to have adversely affected the study.

Principles of method if other than guideline:

Only 3 soils were selected rather than the seven as indicated in the OECD 106 test guideline, however this study predates the updated test guideline (before 2000) where only 3 soil types were required.

GLP compliance:

yes

Type of method:

batch equilibrium method

Media:

soil

Specific details on test material used for the study:

The test material was stored at room temperature.

Radiolabelling:

no

Test temperature:

Not specified

Analytical monitoring:

yes

Remarks:

Total organic carbon (TOC) analysis.

Matrix no.:

#1

Matrix type:

other: Soil from Colorado State UN

% Clay:

36

% Silt:

56

% Sand:

8

% Org. carbon:

2.44

pH:

7.05

CEC:

25.1 meq/100 g soil d.w.

Matrix no.:

#2

Matrix type:

other: Freehold Loamy Sand

% Clay:

11

% Silt:

18

% Sand:

71

% Org. carbon:

0.84

pH:

5.05

CEC:

5.73 meq/100 g soil d.w.

Matrix no.:

#3

Matrix type:

other: Snyder

% Clay:

25

% Silt:

55

% Sand:

17

% Org. carbon:

2.01

pH:

5.53

CEC:

4.12 meq/100 g soil d.w.

Details on matrix:

Three soils were selected which varied significantly in at least one of the following characteristics: cation exchange capacity, clay content, organic matter content and pH.

Details on test conditions:

The adsorption test was run using sieved soil to be less than or equal to 2 mm soil, which was re-equilibrated with approximately twice its weight of water before use by gently tumbling the soil and water together for 2 hours. Soil tests were replicated three times.

Sample No.:

#1

Type:

Koc

Value:

301 dimensionless

pH:

7.05

Matrix:

Colorado soil

% Org. carbon:

2.44

Sample No.:

#2

Type:

Koc

Value:

257 dimensionless

pH:

5.05

Matrix:

Freehold soil

% Org. carbon:

0.84

Sample No.:

#3

Type:

Koc

Value:

118 dimensionless

pH:

5.53

Matrix:

Snyder soil

% Org. carbon:

2.01

Adsorption and desorption constants:

Mean percent adsorbed:
Colorado soil: 59%
Snyder soil: 37%
Freehold soil: 36%
Mean percent desorbed:
Colorado soil: 26%
Snyder soil: 35%
Freehold soil: 32%

Transformation products:

not measured

Details on results (Batch equilibrium method):

The water soluble fraction showed moderate adsorption to each of the three soils tested. Results show 59% adsorption to the high organic carbon content Colorado soil, 37% adsorption to the moderate organic carbon content Snyder soil, and 36% to the low organic carbon Freehold soil.
Desorption results after two washings with fresh sodium chloride showed 26% of the adsorbed test substance was removed from the Colorado soil, 35% removed from the Snyder soil and 31% removed from the Freehold soil. The test substance most strongly retained to the Colorado soil and exhibited less retention to similar extents on both the Snyder soil and Freehold soil.

Validity criteria fulfilled:

yes

Conclusions:

The adsorption coefficients, K' were determined to be 7.34, 2.38 and 2.16 for the Colorado soil, Snyder soil and Freehold soil, respectively.
The adsorption coefficients, Koc, were calculated as a function of the organic carbon content of the soil:
Koc = 301 for the Colorado soil;
Koc = 118 for the Snyder soil and;
Koc = 257 for the Freehold soil.

Executive summary:

The migratory behaviour of the test substance was evaluated in a soil-water system. This procedure was based on that outlined in the OECD Test Guideline 106 Adsorption/Desorption (1993). This method was used to determine the sorption of the test substance in three different soils. The test substance was evaluated in triplicate soil-water test systems for each soil concentration at a loading of 100 g/L.

Mean percent adsorbed:

Colorado soil: 59%

Snyder soil: 37%

Freehold soil: 36%

Mean percent desorbed:

Colorado soil: 26%

Snyder soil: 35%

Freehold soil: 32%

Mean percent retained of initial adsorbed:

Colorado soil: 74%

Snyder soil: 65%

Freehold soil: 69%

Adsorption coefficient (K'):

Colorado soil: 7.34

Snyder soil: 2.38

Freehold soil: 2.16

Adsorption coefficient based on organic carbon content (Koc):

Colorado soil: 301 (log Koc = 2.48)

Snyder soil: 118 (log Koc = 2.07)

Freehold soil: 257 (log Koc = 2.41)

Description of key information

The migratory behaviour of the test substance was evaluated in a soil-water system. This procedure was based on that outlined in the OECD Test Guideline 106 Adsorption/Desorption (1993). This method was used to determine the sorption of the test substance in three different soils. The test substance was evaluated in triplicate soil-water test systems for each soil concentration at a loading of 100 g/L.

Mean percent adsorbed:

Colorado soil: 59%

Snyder soil: 37%

Freehold soil: 36%

Mean percent desorbed:

Colorado soil: 26%

Snyder soil: 35%

Freehold soil: 32%

Mean percent retained of initial adsorbed:

Colorado soil: 74%

Snyder soil: 65%

Freehold soil: 69%

Adsorption coefficient (K'):

Colorado soil: 7.34

Snyder soil: 2.38

Freehold soil: 2.16

Adsorption coefficient based on organic carbon content (Koc):

Colorado soil: 301

Snyder soil: 118

Freehold soil: 257

For the purposes of the safety assessment, the average Koc of 225 will be used.

Key value for chemical safety assessment

Koc at 20 °C:

225