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Environmental fate & pathways

Adsorption / desorption

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Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
June 14-22 2000
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well documented study performed according to OECD Guideline and GLP.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2000
Report Date:
2000

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)
Deviations:
no
GLP compliance:
yes
Type of method:
batch equilibrium method
Media:
soil

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Isofol 18T
- Substance type: pure active substance
- Physical state: liquid
Radiolabelling:
no

Study design

Test temperature:
23 °C

Batch equilibrium or other method

Analytical monitoring:
yes
Details on sampling:
- Sampling interval: 16 h for adsorption, 16 hr for first wash, 40.5 h for second wash
- Sample storage before analysis: Not identified
Details on matrix:
COLLECTION AND STORAGE
- Geographic location: Richmond, British Columbia, Canada

PROPERTIES
Soil 1 - Very Strongly to Strongly Acid Sandy Soil
- Soil texture
- % sand: 89
- % silt: 8
- % clay: 3
- Horizon: Bmz
- Soil taxonomic classification: Orthic Humic Podzol
- Soil order: Podzolic
- pH: 5.1
- Organic carbon (%): 1.9
- CEC (meq/100 g): 12.2
- Carbonate as CaCO3: 1.89

Soil 2 - Moderately or Slightly Acid Loamy Soil
- Soil texture
- % sand: 19
- % silt: 56
- % clay: 25
- Horizon: Bnt
- Soil taxonomic classification: Orthic Humic Gleysol
- Soil series: Ladner
- Soil order: Gleysolic
- pH: 5.7
- Organic carbon (%): 0.4
- CEC (meq/100 g): 20.6
- Carbonate as CaCO3: 1.28

Soil 3 - Slightly Alkaline Loamy Soil
- Soil texture
- % sand: 1
- % silt: 69
- % clay: 30
- Horizon: C
- Soil taxonomic classification: Eluviated Eutric Brunisol
- Soil series: Wapta
- Soil order: Brunisolic
- pH: 9.0
- Organic carbon (%): 7.8
- CEC (meq/100 g): 9.7
- Carbonate as CaCO3: 21.84
Details on test conditions:
TEST SYSTEM
- Type, size and further details on reaction vessel: 15 ml polypropylene test tubes
- Amount of soil and water per treatment: 2 g of soil to 10 ml liquid
- Number of reaction vessels/concentration: 2 treatment tubes plus 1 blank per soil type
- Test performed in open system: Yes
- Method of preparation of test solution: 2ml of Alcohols, C16-20 Branched was stirred rapidly in a glass beaker with 200 ml of Ultrapure Water overnight at 23 degrees C to produce saturated solution. The aqueous phase was removed by siphoning with the first 20 ml discarded.
- Are the residues from the adsorption phase used for desorption: Yes
- Method of preparation of soil: Soil samples were pre-equilibrated by adding 2 g of soil and 5 ml of 0.01 M Calcium Chloride solution into 15 ml polypropylene test tubes and mixing for 23 hr.
- Adsorption Method: 5 ml of aqueous Alcohols, C16-20 Branched solution was added to appropriate tubes. The soil solutions were mixed for 16 hrs at 23 degrees C and then centrifuged (2000 rpm, 20 min). The volumes of soil and supernatants were recorded for only 1 tube per soil. The level of supernatants was marked with a felt pen on sides of tubes. The supernatants were decanted into clean 15 ml test tubes for analysis.
- Desorption Method: Calcium Chloride was added to marks on the test tubes containing the soil pellets. The pellets were resuspended and mixed for 16 hrs at 23 degrees C. The contents were centrifuged (2000 rpm, 20 min) and supernatants decanted for analysis (Wash 1). Process was repeated (Wash 2).
- Extraction Method: 2 ml of MTBE was added to test tubes containing decanted supernatant and rapidly mixed (rotomixer, end over end; 23 degrees C; 10 min). The MTBE layer was transferred to glass septum vials for GC-FID analysis.

Results and discussion

Adsorption coefficientopen allclose all
Type:
Koc
Value:
>= 214 - <= 4 170
Type:
log Koc
Value:
>= 2.33 - <= 3.62

Results: Batch equilibrium or other method

Mass balance (%) at end of adsorption phaseopen allclose all
Sample no.:
#1
Duration:
16 h
% Adsorption:
> 88
Sample no.:
#2
Duration:
16 h
% Adsorption:
> 88
Sample no.:
#3
Duration:
16 h
% Adsorption:
> 88
Mass balance (%) at end of desorption phaseopen allclose all
Sample no.:
#1
Duration:
16 h
% Desorption:
< 12
Sample no.:
#1
Duration:
40.5 h
% Desorption:
< 12
Sample no.:
#2
Duration:
16 h
% Desorption:
< 12
Sample no.:
#2
Duration:
40.5 h
% Desorption:
< 12
Sample no.:
#3
Duration:
16 h
% Desorption:
< 12
Sample no.:
#3
Duration:
40.5 h
% Desorption:
< 12
Details on results (Batch equilibrium method):
See Below

Any other information on results incl. tables

Alcohols, C16-20 Branched was not detected by GC in supernatants from the adsorption or desorption phases of the study. Based on these results Alcohols, C16 -20 Branched was found to adsorb extensively (>88%) to the 3 tests soils. Desorption was considered to be <12%. A value for the Koc was not determined in the study. However, using the data from the study and equations from OECD 106 guidelines, values for Koc and log Koc can be determined. The calculated Koc values ranged from 214 to 4170, while the log Koc values ranged from 2.33 to 3.62.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Alcohols, C16-20 Branched adsorbs extensively (>88%) to soil.
Executive summary:

This study determined the % adsorption and desorption of Alcohols, C16 -20 Branched to soil. Alcohols, C16 -20 Branched was mixed with three different soil types for 16 hrs. The samples were centrifiuged and the supernatant analyzed. Alcohols, C16 -20 Branched was determined to adsorb extensively (>88%) to soil. Calculated Koc values ranged from 214 to 4170, while the log Koc values ranged from 2.33 to 3.62.