Registration Dossier

Environmental fate & pathways

Adsorption / desorption

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1 June 2012 to 4 July 2012
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
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:
yes
Remarks:
(see "Principles of method if other than guideline")
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:
yes
Remarks:
(see "Principles of method if other than guideline")
Principles of method if other than guideline:
The guidelines state that the measurement of the adsorption coefficient should be carried out on substances in their ionised and unionised forms. Definite structures were not available to calculate the dissociation constants but it was considered that any acid groups would be carboxylic acids and their dissociation constants would be outside the relevant pH range of the test. Therefore, the test was performed with the mobile phase at an approximately neutral pH.
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
No data available.
Details on study design: HPLC method:
The test material (0.5061 g) was diluted to 20 mL with tetrahydrofuran to give a concenration of 2.53 x 10^4 g/L.

The sample, dead time and reference standard solutions were injected in duplicate using the following HPLC parameters:
- Apparatus: Agilent Technologies 1100 incorporating autosamples, Polymer Laboratories Evaporative Light Scattering Detector 1000 (ELSD), and workstation
- Column: XSelect cyano 5 µm (150 x 4.6 mm id)
- Column temperature: 30 ºC
- Mobile phases: methanol:water (55:45 v/v) (changed to 100% tetrahydrofuran after the elution of the last reference standard to elute the highly retained test material components)
- pH of mobile phase: 6.5
- Flow rate: 1.0 mL/min
- Injection volume: 5 µL
- UV detector wavelength: dead time and reference standards: 210 nm
- ELSD parameters: nebuliser temperature: 40 ºC; evaporative temperature: 80 ºC; gas flow: 1.0 SLM

The mobile phase was changed to 100% tetrahydrofuran after the elution of the last reference standard to elute the highly retained test components.

DETERMINATION OF DEAD TIME
The dead time was determined by measuring the retention time of formamide (purity 99.6%, 735 mg/L solution in mobile phase).

REFERENCE SUBSTANCES:
- Acetanilide (purity ≥ 99%): 100 mg/L
- Phenol (purity ≥ 99%): 171 mg/L
- Atrazine (purity 98.8%): 100 mg/L
- Isoproturon (purity 99.9%): 109 mg/L
- Triadimenol (purity 98.4%): 101 mg/L
- linuron (purity 99.9%): 100 mg/L
- Naphthalene (purity ≥ 99%): 100 mg/L
- Endosulfan-diol (purity 99.9%): 120 mg/L
- Fenthion (purity 98.3%): 147 mg/L
- Phenanthrene (purity 97%): 106 mg/L
- Diclofop-methyl (purity 99.2%) 102 mg/L
- DDT (purity 98%): 187 mg/L
Type:
log Koc
Value:
> 5.63 dimensionless
Remarks on result:
other: no information on temperature available.
Type:
Koc
Value:
> 427 000 dimensionless
Remarks on result:
other: no information on temperature available.
Details on results (HPLC method):
The capacity factor was calculated according to:

k' = (tr - t0 / t0)

where:
k' = capacity factor
tr = retention time (min)
t0 = dead time (min)

A correlation of log k' versus log Koc of the calibration standards was plotted using linear regression.

From the plotted data, the linear regression parameters were calculated as:

Slope = 0.350
Intercept = -0.681
Correlation Coefficient (r) = 0.965

The value of log Koc for the test material was calculated as:

Log Koc = Log k' - intercept / slope

Table 1: Reference solution data

Standard

Retention time (mins)

Mean retention time (mins)

Capacity factor (k')

log k'

log Koc

Injection 1

Injection 2

Acetanilide

2.737

2.737

2.737

0.412

-0.385

1.25

Phenol

2.664

2.625

2.645

0.365

-0.438

1.32

Atrazine

3.843

3.845

3.844

0.983

-0.00723

1.81

Isoproturon

4.187

4.175

4.181

1.16

0.0635

1.86

Triadimenol

5.847

5.861

5.854

2.02

0.305

2.40

Linuron

6.142

6.126

6.122

2.16

0.334

2.59

Naphthalene

5.141

5.143

5.142

1.65

0.218

2.75

Endosulfan-diol

7.923

7.889

7.906

3.08

0.488

3.02

Fenthion

9.418

9.401

9.410

3.86

0.586

3.31

Phenanthrene

10.204

10.216

10.210

4.27

0.630

4.09

Diclofop-methyl

14.816

14.833

14.825

6.65

0.823

4.20

 DDT

31.075

31.038

31.057

15.0

1.18

5.63

Table 2: Test material solution data

Injection

Retention time (mins)

Capacity factor (k')

log k'

log Koc

1

> 31.1

> 15.0

> 1.18

> 5.63

2

> 31.1

> 15.0

> 1.18

> 5.63

Validity criteria fulfilled:
yes
Conclusions:
Under the conditions of the test, the adsorption coefficient (Koc) of the test material was determined to be > 4.27 x 10⁵ (Log Koc > 5.63). This value indicates that the test material is immobile.
Executive summary:

The adsorption coefficient of the test material was determined in accordance with the standardised guidelines OECD 121 and EU Method C.19, using the HPLC screening method. Under the conditions of the test, the adsorption coefficient (Koc) of the test material was determined to be > 4.27 x 10(Log Koc > 5.63). This value indicates that the test material is immobile.

Endpoint:
adsorption / desorption: screening
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Justification for type of information:
See read-across justification attached in Section 13.
Reason / purpose:
read-across source
Type:
log Koc
Value:
> 5.63 dimensionless
Remarks on result:
other: no information on temperature available
Type:
Koc
Value:
427 000 dimensionless
Remarks on result:
other: no information on temperature available

Description of key information

The Log Koc of an analogue test material (EC 265-205-1) was determined to be > 5.63 according to a GLP compliant key study (Fox, 2012) performed according to OECD 121 and EU Method C.19.

Key value for chemical safety assessment

Koc at 20 °C:
427 000

Additional information

The key study (Fox, 2012) is a GLP compliant study which was performed in accordance with standardised guidelines OECD 121 and EU Method C.19 with a sufficient level of detail to assess the quality of the presented results. The Log Koc of an analogue test material (EC 265-205-1) was determined, using the HPLC screening method to be > 5.63. This value indicates that the test material is immobile.

[LogKoc: 5.63]