Registration Dossier

Environmental fate & pathways

Adsorption / desorption

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 22 June 2009 to 25 June 2009
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
This study was performed according to OECD Guideline 121 and EU Method C.19 with GLP statement. This study is well documented and all validity criteria were fulfilled. No deviations were observed.
Qualifier:
according to
Guideline:
OECD Guideline 121 (Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC))
Version / remarks:
22 January 2001
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
Version / remarks:
30 May 2008
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes (incl. certificate)
Remarks:
2009-03-04
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
30°C (Column temperature)
Details on study design: HPLC method:
EQUIPMENT
- Apparatus: HPLC System
- Type: Agilent Technologies 1100, incorporating autosampler and workstation.
- Type, material and dimension of analytical (guard) column: Column = Phenosphere Next CN 5µ (250 x 4.6 mm id)
- Detection system: UV detector wavelength

MOBILE PHASES
- Type: Methanol:water (55:45 v/v)
- pH: 6.75
- Solutes for dissolving test and reference substances: The test item and reference standards were prepared in methanol. The dead time solution was diluted in methanol:water (55:45 v/v).

DETERMINATION OF DEAD TIME
- Method: by inert substances which are not retained by the column (formamide, purity 99.94%)

REFERENCE SUBSTANCES
- Identity: Acetanilide, Phenol, Atrazine, Isoproturon, Triadimenol, Linuron, Naphthalene, Endosulfan-diol, Fenthion, alpha-Endosulfan, Phenanthrene, Diclofop-methyl, DDT.

DETERMINATION OF RETENTION TIMES
- Quantity introduced in the column: Injection volume 10 µL; Flow rate 1.0 mL/min.

REPETITIONS
- Number of determinations: The sample, dead time and reference standard solutions were injected in duplicate.

EVALUATION
- Calculation of capacity factors k' = (tr - t0) / t0, which tr = retention time (min) and t0 = dead time (min).
- Determination of the log Koc value = (log k' - A) / B, which A = intercept of the calibration curve and B = slope of the calibration curve.
Details on sampling:
Not applicable
Details on matrix:
Not applicable
Details on test conditions:
Not applicable
Computational methods:
Not applicable
Key result
Type:
log Koc
Value:
1.91
Temp.:
30 °C
Key result
Type:
Koc
Value:
80.5
Temp.:
30 °C
Details on results (HPLC method):
- Retention times of reference substances used for calibration: See table 5.4.1/1 in "Any other information on results incl. tables".
- Details of fitted regression line (log k' vs. log Koc): A = -1.063; B = 0.355; r²=0.977.
- Graph of regression line attached: Yes. See in "Illustration"
- Average retention data for test substance: See table 5.4.1/2 in "Any other information on results incl. tables".

The method guidelines require determination of adsorption coefficient on the ionised and non-ionised forms of a test material, if dissociation is possible within the environmentally relevant pH range. However, in the absence of such dissociating groups, a single determination only was performed at an approximately neutral pH, with the test material in a non-ionised form.
Adsorption and desorption constants:
Not applicable
Recovery of test material:
Not applicable
Concentration of test substance at end of adsorption equilibration period:
Not applicable
Concentration of test substance at end of desorption equilibration period:
Not applicable
Transformation products:
not measured
Details on results (Batch equilibrium method):
Not applicable
Statistics:
Not applicable

Table 5.4.1/1: The retention times of the dead time and the reference times, capacity factors and log Koc values for the reference standards

Standard

Retention time (mins)

Mean retention time (mins)

Capacity factor (k')

Log k’

Log Koc

Injection 1

Injection 2

Formamide

3.298

3.299

3.299

-

-

-

Acetanilide

4.003

4.003

4.003

0.214

-0.670

1.25

Phenol

3.993

3.993

3.993

0.211

-0.677

1.32

Atrazine

4.424

4.427

4.426

0.342

-0.466

1.81

Isoproturon

4.777

4.778

4.778

0.448

-0.348

1.86

Triadimenol

5.149

5.151

5.150

0.561

-0.251

2.40

Linuron

5.933

5.937

5.935

0.799

-9.729 x 10-2

2.59

Naphthalene

7.484

7.484

7.484

1.269

0.103

2.75

Endosulfan-diol

5.824

5.823

5.824

0.765

-0.116

3.02

Fenthion

9.646

9.646

9.646

1.924

0.284

3.31

Alpha-Endosulfan

9.829

9.831

9.830

1.980

0.297

4.09

Phenanthrene

12.924

12.923

12.924

2.918

0.465

4.09

Diclofop-methyl

11.821

11.819

11.820

2.583

0.412

4.20

DDT

27.412

27.428

27.420

7.313

0.864

5.63

Table 5.4.1/2: The retention times, capacity factor and log Koc values determined for the sample

Injection

Retention time (mins)

Capacity factor (k’)

Log k’

Log Koc

1

4.656

0.412

-0.386

1.906

2

4.656

0.412

-0.386

1.906

Validity criteria fulfilled:
yes
Conclusions:
The adsorption coefficient (Koc) of the test substance has been determined to be 80.5 (log Koc = 1.91). The result indicates that the test item is highly mobile (according to P.J. McCall et al., 1980).
Executive summary:

This study was performed according to OECD Guideline 121 and EU Method C.19 with GLP statement, to assess the adsorption coefficient of the test substance. The test utilized a high performance liquid chromatograph. A commercially available cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties was used.

As the slope of the calibration curve for the reference standards showed good first order correlation and as the retention times between duplicate injections for the test substance was similar, the HPLC method was considered valid for the determination of adsorption coefficient. All validity criteria were fulfilled.

The adsorption coefficient (Koc) of the test substance has been determined to be 80.5 (log Koc = 1.91). The result indicates that the test item is highly mobile (according to P.J. McCall et al., 1980).

Description of key information

OECD Guideline 121, EU Method C.19, GLP, key study, validity 1:
Koc = 80.5; log Koc = 1.91
Highly mobile in soils (according to P.J. McCall et al., 1980).

Key value for chemical safety assessment

Koc at 20 °C:
80.5

Additional information

One valid key study is available to assess the adsorption coefficient of the substance. This study was performed according to OECD Guideline 121 and EU Method C.19 with GLP statement. The test utilised a high performance liquid chromatograph (HPLC). A commercially available cyanopropyl reverse phase HPLC column containing lipophilic and polar moieties was used.

As the slope of the calibration curve for the reference standards showed good first order correlation and as the retention times between duplicate injections for the substance was similar, the HPLC method was considered valid for the determination of adsorption coefficient. All validity criteria were fulfilled.

The adsorption coefficient (Koc) of the substance has been determined to be 80.5 (log Koc = 1.91). The result indicates that the substance is highly mobile in soils (according to P.J. McCall et al., 19811).

1McCall P.J., Laskowski D.A., Swann R.L., and Dishburger H.J., (1981), “Measurement of sorption coefficients of organic chemicals and their use, in environmental fate analysis”, in Test Protocols for Environmental Fate and Movement of Toxicants. Proceedings of AOAC Symposium, AOAC,

Washington DC.

Mobility classification scheme:

Range of Koc

Mobility class

0 - 50

Very high

50 - 150

High

150 - 500

Medium

500 - 2000

Low

2000 - 5000

Slightly

> 5000

Immobile

[LogKoc: 1.91]