Registration Dossier

Administrative data

Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Testing was conducted between 27 March 2007 and 11 June 2007.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the relevant results.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report Date:
2007

Materials and methods

Test guidelineopen allclose all
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
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC estimation method
Media:
soil/sewage sludge

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Sponsor's identification: C-Y9
Description : yellow powder
Lot number : MB-1
Date received : 6 March 2007
Storage conditions: room temperature in the dark, over silica gel
Radiolabelling:
no

Study design

Test temperature:
30ºC

HPLC method

Details on study design: HPLC method:
Procedure:
Preparation of sample solution:
Test material (0.0101 g) was diluted to 100 ml with reverse osmosis water.

Preparation of reference solutions:
The dead time was determined by measuring the retention time of formamide (purity 99.5%, 1.25 x 10E3 mg/l solution in methanol: reverse osmosis water (55: 45 v/v)).
Solutions of reference standards (see table in any other information on materials and methods section) were prepared in methanol.

Determination of retention time:
The sample, formamide and reference standard solutions were injected in duplicate using the following HPLC parameters:

HPLC System : Agilent Technologies 1050, incorporating autosampler and workstation
Column : Zorbax SB-CN 5µ (250 x 4.6 mm id)
Column temperature: 30ºC
Mobile phase : methanol: reverse osmosis water (55:45 v/v)
pH of mobile phase: 6.35 - 7.11
Flow-rate : 1 ml/min
UV/vis detector wavelength : dead time and reference standards: 210 nm
sample: 390 nm
Injection volume : 10 µl

Construction of calibration curve:
A calibration curve was constructed from the retention time data of the formamide and reference standard solutions. The capacity factors (k) for the reference standards were calculated using the below equation (see calculation).

Adsorption coefficient of sample:
The capacity factor was calculated using the below equation (see calculation) and the log10 Koc value determined with reference to the calibration curve.

Calculation:
The capacity factor was determined using the following equation:
k = tr - t0 / t0

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









Results and discussion

Adsorption coefficient
Type:
log Koc
Value:
< 1.25
Temp.:
30 °C

Results: HPLC method

Details on results (HPLC method):
Please see any other information on results section.

Any other information on results incl. tables

Calibration:

The retention times of formamide and the retention times, capacity factors (k) and log10Kocvalues for the reference standards are shown in the two following tables:

Dead Time

Retention Time (mins)

Mean Retention Time (mins)

Injection 1

Injection 2

Formamide

2.881

2.878

2.880

Standard

Retention Time (mins)

Mean Retention Time (mins)

Capacity Factor (k)

Log10k

Log10Koc

Injection 1

Injection 2

Acetanilide

4.125

4.128

4.127

0.433

-0.363

1.25

Phenol

3.930

3.935

3.933

0.366

-0.437

1.32

Atrazine

6.169

6.171

6.170

1.143

5.794 x 10-2

1.81

Isoproturon

6.644

6.652

6.648

1.309

0.117

1.86

Triadimenol

9.342

9.351

9.347

2.246

0.351

2.40

Linuron

16.775

16.799

16.787

4.830

0.684

2.59

Endosulfan-diol

12.388

12.411

12.400

3.306

0.519

3.02

a-Endosulfan

23.714

23.535

23.625

7.204

0.858

4.09

Phenanthrene

18.461

18.447

18.454

5.409

0.733

4.09

DDT

57.283

57.271

57.277

18.891

1.276

5.63

Adsorption coefficient of sample

The retention times, capacity factors and log10Kocvalues determined for the sample are shown in the following table:

Injection

Retention Time (mins)

Capacity Factor (k)

Log10k

Log10Koc

1

1.785

< 0.433

< -0.363

< 1.25

2

1.786

< 0.433

< -0.363

< 1.25

Mean log10Koc:             < 1.25
Adsorption coefficient:   < 17.8

Discussion

The method guideline states that the measurement of adsorption coefficient should be carried out on substances in their ionised and unionised forms. However, the dissociation constants of the sulphonic acid sodium salt functional groups found in the test material made it impossible to satisfy this criteria as a pH < 0 would be required. As a consequence of this, the functional groups will always be present in their ionised form. Therefore, as pH < 0 is outside the environmental pH range for this test and also experimentally impractical, testing was carried out at approximately neutral pH with the sulphonic acid sodium salt functional groups ionised.

As the test material eluted before the deadtime, probably due to being ionised, no calculations for log10K were possible, so a result of less than the lowest reference standard used (acetanilide) was quoted.

The low adsorption property of the test material determined by the HPLC estimation method is consistent with the extremely high water solubility and low partition coefficient characteristics. The determined value is believed to accurately assess the affinity of the test material for the organic carbon content of soils and sewage sludge. The mobility of the test material in soil and sewage sludge may also be influenced by additional interactions other than partitioning, not addressed by the test method due to its anionic nature.

The alternative use of computer-based estimation programs and/or Quantitative Structure Activity Relationships (QSAR’s) for materials of this nature are considered invalid as estimates are typically derived from the partition coefficient value. Therefore once more the possible interaction originating from the anionic charges are not addressed.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
The adsorption coefficient (Koc) of the test material has been determined to be < 17.8, log10 Koc < 1.25.
Executive summary:

Adsorption Coefficient. 

< 17.8, log10Koc < 1.25, using the HPLC screening method, Method C19 of Commission Directive 2001/59/EC and Method 121 of the OECD Guidelines for Testing of Chemicals, 22 January 2001.