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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 28 May 2012 to 30 May 2012
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
This study was performed according to EU Method C.19 and OECD Guideline 121 with GLP statement. This study is well documented and all validity criteria were fulfilled. No deviations were observed.
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))
Deviations:
no
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))
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC estimation method
Media:
soil
Specific details on test material used for the study:
- Storage condition of test material: Room temperature, dry area, unopened containers, optimum temperature 11-25°C
Radiolabelling:
no
Test temperature:
25°C (Column temperature)
Details on study design: HPLC method:
EQUIPMENT
- Apparatus: HPLC System
- Type: Agilent 1200 Series Liquid Chromatograph.
- Type, material and dimension of analytical (guard) column: Column = Hyperclone CN (CPS) (25 cm x 4.6 mm id)
- Detection system: UV detector wavelength (210 nm)

MOBILE PHASES
- Type: Acetonitrile:water (55:45 v/v)
- pH: no data
- Solutes for dissolving test and reference substances: HPLC mobile phase.

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

REFERENCE SUBSTANCES
- Identity: Acetanilide, Nitrobenzene, Naphthalene, 2-Methylnaphthalene, Anthracene, DDT.

DETERMINATION OF RETENTION TIMES
- Quantity introduced in the column: Injection volume 20 µL; Flow rate 1.0 mL/min.

REPETITIONS
- Number of determinations: 2

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:
4.3 dimensionless
Temp.:
25 °C
Key result
Type:
Koc
Value:
21 000 L/kg
Temp.:
25 °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): log Koc = 4.49*log k' + 4.07 (r² = 0.94)
- Graph of regression line attached: Yes. See in "Illustration"
- Average retention data for test substance: See table 5.4.1/1 in "Any other information on results incl. tables".
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: Determination of log Koc for the test substance

Sample

Component

tr (min)

k’

Log k’

Log Koc

Standard Run A

(t0 = 2.834 min)

Acetanilide

Nitrobenzene

Naphthalene

2-methylnaphthalene

Anthracene

DDT

3.401

4.181

4.872

5.172

5.765

8.640

0.200

0.475

0.719

0.825

1.034

2.049

-0.699

-0.323

-0.143

-0.084

0.015

0.311

1.3

2.4

2.8

3.9

4.4

5.6

Sample A

(t0 = 2.831 min)

Test substance

6.062

1.141

0.057

4.3

Sample B

(t0 = 2.832 min)

Test substance

6.064

1.141

0.057

4.3

Standard Run B

(t0 = 2.832 min)

Acetanilide

Nitrobenzene

Naphthalene

2-methylnaphthalene

Anthracene

DDT

3.400

4.180

4.871

5.171

5.764

8.642

0.201

0.476

0.720

0.826

1.035

2.052

-0.698

-0.322

-0.143

-0.083

0.015

0.312

1.3

2.4

2.8

3.9

4.4

5.6

Validity criteria fulfilled:
yes
Conclusions:
The substance was determined to have a log Koc value of 4.3 (equivalent to Koc = 21000 L/kg).
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 analytical column packed with a solid phase containing a moderately polar stationary phase with lipophilic and polar moieties was used.

In order to correlate the measured capacity factor (k') of the test substance with its Koc, six reference materials were selected from a list of recommended compounds. These reference compounds were selected to have log Koc values between 1.3 and 5.6. An internal standard (formamide) with no retention on the HPLC column was used to determine the deadtime of the HPLC system.

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 each solution was consistent, the HPLC method was considered valid for the determination of adsorption coefficient.

All validity criteria were fulfilled.

The substance was determined to have a log Koc value of 4.3 (equivalent to Koc = 21000 L/kg).

Description of key information

OECD Guideline 121, EU Method C.19, GLP, key study, validity 1:

log Koc = 4.3; Koc = 21000

Immobile in soils (according to P.J. McCall et al., 1980)

Key value for chemical safety assessment

Koc at 20 °C:
21 000

Additional information

One valid key study is available to assess the adsorption coefficient of the registered substance. This study was performed according to OECD Guideline 121 and EU Method C.19 with GLP statement. The test utilized a high performance liquid chromatograph. A commercially available analytical column packed with a solid phase containing a moderately polar stationary phase with lipophilic and polar moieties was used.

In order to correlate the measured capacity factor (k') of the substance with its Koc, six reference materials were selected from a list of recommended compounds. These reference compounds were selected to have log Koc values between 1.3 and 5.6. An internal standard (formamide) with no retention on the HPLC column was used to determine the deadtime of the HPLC system.

All validity criteria were fulfilled.

The substance was determined to have a log Koc value of 4.3 (equivalent to Koc = 21000). This result indicates that the registered substance is immobile in soils (according to P.J. McCall et al., 19801).

1McCall P.J., Swann RL, Laskowski D.A., Unger SM, Vrona SA and Dishburger H.J., (1980), “Estimation of chemical mobility in soil from liquid chromatographic retention times”, Bull Environ Contam Toxicol 24 (2) 190 -5.

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: 4.3]