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Adsorption / desorption

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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:
13th April - 10th May 2010
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. Study read across from shale oil, middle fraction.
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
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
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
HPLC temp, 25 ºC
Details on study design: HPLC method:
EQUIPMENT
- Apparatus: Shimadzu LC-20AC with DAD detector
- Type: HPLC
- Type, material and dimension of analytical (guard)
- Column: Agilent ZORBAX CN, 5µm, 150 x 4.6 mm
- Detection system: DAD detector

MOBILE PHASES
- Type: Polar
- Experiments with additives carried out on separate columns: N/A
- pH: 7.9
- Solvent for dissolving test and reference substances: methanol

DETERMINATION OF DEAD TIME
- Method: by means of homologous series / by inert substances which are not retained by the column

REFERENCE SUBSTANCES
- Identity: The specified amount of reference compound was weighed into a 25 mL volumetric flask and dissolved and diluted to volume with mobile phase.
Two calibration mixtures were prepared from these stock solutions of reference compounds:

Calibration mixture 6: 10.48 mg acetanilide, 25.30 mg of phenyl benzoate and 25.07 mg of phenanthrene were weighed together into a 25 mL volumetric flask and dissolved and diluted to volume with methanol. Then 3 mL aliquot was pipetted into a 25 mL volumetric flask and diluted to volume with mobile phase.

Calibration mixture 7: 17.59 mg benzamide, 25.25 mg of 2,5-dichloraniline and 26.11 mg of Fenthion were weighed together into a 25 mL volumetric flask and dissolved and diluted to volume with methanol Then 5 mL aliquot was pipetted into a 25 mL volumetric flask and diluted to volume with mobile phase.

Test substance (Shale oils, middle): 3 mL of test substance was pipetted into a 50 mL volumetric flask and dissolved and diluted to volume with methanol. Then 1 mL aliquot was pipetted into a 50 mL volumetric flask and diluted to volume with methanol. To prevent precipitation of the test sample, MeOH was used as a sample solvent.

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 10 µl of test substance solution
- Quantity of reference substances: 10 µl of reference substance solution
- Intervals of calibration: NDA

REPETITIONS
- Number of determinations: 4

EVALUATION
- Calculation of capacity factors k':
- Calculation of retention times:
- Determination of the log Koc value:
Computational methods:
Calibration line was constructed with a statistical software EffiValidation 3.0.2410, 1999-2004 by EffiChem, Czech Republic. Other calculations were done with the Microsoft Excel 2000 software (9.0.3821 SR-I).
Adsorption coefficient and uncertainty caculations are presented in the "Any other information on materials and methods incl. tables" and attachments sections.
Type:
log Koc
Value:
-0.2 - 6.4
Temp.:
25 °C
Remarks on result:
other: soil
Type:
log Koc
Value:
0.4 - 6.3
Temp.:
25 °C
Remarks on result:
other: sludge
Details on results (HPLC method):
Because of complex composition of the test substance with no main component, a lower and upper limit of both log Koc (soil) and log Koc (sludge) were determined. Since both lower and upper limit of log Koc (soil) and log Koc (sludge) of the test substance (shale oils, middle) are out of the range of the reference compounds, the results are considered less reliable.
Statistics:
Student's t-distribution

Table 1: Log KOC values for reference substances in soil

Reference Compound

Log KOC

Acetanilide

1.25

Benzamide

1.26

2.5-Dichloroaniline

2.55

Phenyl benzoate

2.87

Fenthion

3.31

Phenathrene

4.09

Table 2: Log KOC values for reference substances in sludge

Reference Compound

Log KOC

Acetanilide

1.52

Benzamide

1.60

2.5-Dichloroaniline

2.45

Phenyl benzoate

3.26

Fenthion

3.75

Phenathrene

4.35

Validity criteria fulfilled:
yes
Conclusions:
Lower and Upper limit of adsorption coefficient of the test substance (shale oils, middle) on soil:
log Koc = 0.5 ± 0.7 (pH = 7.9, 25 °C)
log Koc = 5.5 ± 0.9 (pH = 7.9, 25 °C)

Lower and Upper limit of adsorption coefficient of the test substance (shale oils, middle) on sewage sludge:
log Koc = 0.8 ± 0.4 (pH = 7.9, 25 °C)
log Koc = 5.8 ± 0.5 (pH = 7.9, 25 °C)

Since both lower and upper limit of log Koc (soil) and log Koc (sludge) of the test substance (shale oils, middle) are out of the range of the reference compounds, the results are considered less reliable.
Executive summary:

The adsorption coefficient of test substance, Shale oils, middle, on soil and on sewage sludge was estimated. The HPLC method with reference compounds was used.

The test was performed according to the Method C.19, Estimation of the adsorption coefficient (Koc) on soil and sewage sludge using high performance liquid chromatography (HPLC), Council Regulation (EC) No 440/2008.

Lower and Upper limit of adsorption coefficient of the test substance (shale oils, middle) on soil:

log Koc = 0.5 ± 0.7 (pH = 7.9, 25 °C)

log Koc = 5.5 ± 0.9 (pH = 7.9, 25 °C)

Lower and Upper limit of adsorption coefficient of the test substance (shale oils, middle) on sewage sludge:

log Koc = 0.8 ± 0.4 (pH = 7.9, 25 °C)

log Koc = 5.8 ± 0.5 (pH = 7.9, 25 °C)

Since both lower and upper limit of log Koc (soil) and log Koc (sludge) of the test substance (shale oils, middle) are out of the range of the reference compounds, the results are considered less reliable.

Based on the rationale for read-across, it is considered acceptable to use this study to address the same endpoint for light fraction of shale oil.

Endpoint:
adsorption / desorption: screening
Remarks:
Further information on adsorption/desorption
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
In accordance with Section 1 of Annex XI of the REACH regulation, it was considered scientifically unjustified to conduct a further adsorption/desorption study (required in 9.3.3), based on the existing data available. Results of the adsorption screening study could not give an accurate Koc value due to the poorly defined nature of the substance. A further study would give no additional information.

Description of key information

Lower and Upper limit of adsorption coefficient of the test substance (shale oils, middle) on soil:
log Koc = 0.5 ± 0.7 (pH = 7.9, 25 °C)
log Koc = 5.5 ± 0.9 (pH = 7.9, 25 °C)
Lower and Upper limit of adsorption coefficient of the test substance (shale oils, middle) on sewage sludge:
log Koc = 0.8 ± 0.4 (pH = 7.9, 25 °C)
log Koc = 5.8 ± 0.5 (pH = 7.9, 25 °C)

Key value for chemical safety assessment

Additional information

The adsorption coefficient of the test material, Shale oils, middle, on soil and on sewage sludge was estimated in a study which was conducted in accordance with the standardised guidelines OECD 121 and EU Method C.19, under GLP conditions, following the HPLC method. The study was awarded a reliability score of 2 in accordance with the criteria set forth by Klimisch et al. (1997).


Under the conditions of the study, the following results were generated:


Lower and Upper limit of adsorption coefficient of the test substance (shale oils, middle) on soil:


log Koc = 0.5 ± 0.7 (pH = 7.9, 25 °C)


log Koc = 5.5 ± 0.9 (pH = 7.9, 25 °C)


 


Lower and Upper limit of adsorption coefficient of the test substance (shale oils, middle) on sewage sludge:


log Koc = 0.8 ± 0.4 (pH = 7.9, 25 °C)


log Koc = 5.8 ± 0.5 (pH = 7.9, 25 °C)


 


Since both lower and upper limit of log Koc (soil) and log Koc (sludge) of the test substance (shale oils, middle) are out of the range of the reference compounds, the results are considered less reliable.


 


In accordance with Section 1 of Annex XI of the REACH regulation, it was considered scientifically unjustified to conduct a further adsorption/desorption study (required in 9.3.3), based on the existing data available. Results of the adsorption screening study could not give an accurate Koc value due to the poorly defined nature of the substance. A further study would give no additional information.