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Environmental fate & pathways

Adsorption / desorption

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Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Study period:
1998-08-03 - 199-02-08
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP guideline study conducted with valid source substance. For detailed justification of the read-across procedure, please refer to the separate statement by Chemservice S.A. (2013).

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report Date:
1999

Materials and methods

Test guideline
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))
GLP compliance:
yes (incl. certificate)
Remarks:
The Department of Health of the Government of The United Kingdom
Type of method:
HPLC estimation method
Media:
soil

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid: viscous
Details on test material:
Not applicable.
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
- Physical state: Extremely pale yellow straw coloured viscous liquid
- Storage conditions: Room temperature, in darkness

Study design

Test temperature:
30 °C

HPLC method

Details on study design: HPLC method:
PREPARATION OF SAMPLE SOLUTION
1.9940 g of test substance was diluted to 100 mL with methanol.

PREPARATION OF REFERENCE SOLUTIONS
The dead time was determined by measuring the retention time of formamide (purity 99.5 %, 1.14 x 10E3 mg/L) solution in methanol.
Acetanilide, phenol, atrazine, isoproturon, naphthalene, fenthion, alpha endosulfan, pyrazophos, phenanthrene, diclofop-methyl and DDT served as reference standards and were prepared in methanol.

HPLC PARAMETERS
- System: Hewlett-Packard 1050, incorporating autosampler and workstation
- Column: Hypersil 5µ CN BDS (250 mm x 4.6 mm id)
- Column temperature: 30 °C
- Mobile phase: methanol:water (55:45 v/v)
- pH of mobile phase: 5.9
- Flow rate: 1.0 mL/min
- UV detector wavelength: 210 nm
- Injection volume: 10 µL

CALCULATION OF CAPACITY FACTORS (k)
k = tr - t0 / t0
whereby:
k - capacity factor
tr - retention time [min]
t0 - dead time [min]

Results and discussion

Adsorption coefficientopen allclose all
Type:
log Koc
Value:
1.25 - 3.69
Temp.:
30 °C
Type:
Koc
Value:
17.8 - 4 930
Temp.:
30 °C

Results: HPLC method

Details on results (HPLC method):
The measurement of adsorption coefficient should be carried out on substances in their ionised and unionised forms. However the dissociation constants of the test substance are outside the environmental pH range required for this test (it is also not practical to employ such low pH (~3) or high pH (~12) in the test); since adjustment was not environmentally relevant or experimentally practical, measurement was carried out on the ionised form only.
A calculated value of adsorption coefficient was derived for each whole salt using a computer-based atom fragment contribution method. The result was logKoc = 4.3 and 6.2.
The components of the test substance were also considered and calculated individually. The two acid components gave logKoc values of 1.9 and 3.9, and the amine component gave a logKoc of 2.8.

Any other information on results incl. tables

Table 2. Retention times of formamide and reference standards

Standard

Retention time [min]

Mean retention time [min]

Injection 1

Injection 2

Formamide (dead time)

3.235

3.234

3.235

Acetanilide

3.627

3.627

3.627

Phenol

3.583

3.580

3.582

Atrazine

3.991

3.992

3.992

Isoproturon

4.188

4.188

4.188

Naphthalene

4.967

4.964

4.966

Fenthion

6.307

6.309

6.308

Alpha endosulfan

8.811

8.814

8.813

Pyrazophos

6.698

6.699

6.699

Phenanthrene

8.337

8.309

8.323

Diclofop-methyl

8.657

8.645

8.651

DDT

19.294

19.267

19.281

Table 3. Capacity factor (k), logk and logKoc for the reference standards

Standard

Capacity factor (k)

logk

logKoc

Acetanilide

0.121

-0.916

1.25

Phenol

0.107

-0.969

1.32

Atrazine

0.234

-0.631

1.81

Isoproturon

0.295

-0.530

1.86

Naphthalene

0.535

-0.272

2.75

Fenthion

0.950

-2.217 x 10E-2

3.31

Alpha endosulfan

1.725

0.237

4.09

Pyrazophos

1.071

2.977 x 10E-2

3.65

Phenanthrene

1.573

0.197

4.09

Diclofop-methyl

1.675

0.224

4.20

DDT

4.961

0.696

5.63

Table 4. Retention time, capacity factors and logKoc for the sample

Component

Injection

Retention times [min]

Capacity factor (k)

logk

logKoc

First

1

2.658

-0.178

-

< 1.25

2

2.344

-0.275

-

Final

1

6.840

1.115

4.716 x 10E-2

3.69

2

6.860

1.121

4.956 x 10E-2

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
Validity criteria of the applied guideline were fulfilled.
Conclusions:
The study report describes a valid guideline study conducted under certificated GLP compliance. The adsorption coefficient has been determined to be in the range < 17.8 - 4.93 x 10E3 with a corresponding logKoc range of < 1.25 - 3.69.
Executive summary:

The determination of the adsorption coefficient was carried out using the High Performance Liquid Chromatography (HPLC) screening method specified in the draft of the OECD Guideline 121 (Lumsden, 1999). The test substance was diluted with methanol. The dead time was determined using formamide and acetanilide, phenol, atrazine, isoproturon, naphthalene, fenthion, alpha endosulfan, pyrazophos, phenanthrene, diclofop-methyl and DDT served as reference standards. The temperature was set at 30 °C and the pH of the mobile phase was measured as 5.9. The measurement of adsorption coefficient should be carried out on substances in their ionised and unionised forms. However the dissociation constants of the test substance are outside the environmental pH range required for this test (it is also not practical to employ such low pH (~3) or high pH (~12) in the test); since adjustment was not environmentally relevant or experimentally practical, measurement was carried out on the ionised form only. A calculated value of adsorption coefficient was derived for each whole salt using a computer-based atom fragment contribution method. The result was logKoc = 4.3 and 6.2. The components of the test substance were also considered and calculated individually. The two acid components gave logKoc values of 1.9 and 3.9, and the amine component gave a logKoc of 2.8. The overall logKoc is in the range < 1.25 - 3.69. The adsorption coefficient (Koc) is therefore in the range < 17.8 - 4.93 x 10E3.