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Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
20 - 21 November 2014
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
This study was performed according to OECD Guideline 121 with GLP statement. All validity criteria were fulfilled.
Qualifier:
according to guideline
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
Guideline:
EU Method C.19 (Estimation of the Adsorption Coefficient (KOC) on Soil and Sewage Sludge Using High Performance Liquid Chromatography (HPLC))
Deviations:
no
Principles of method if other than guideline:
Not applicable
GLP compliance:
yes (incl. QA statement)
Remarks:
inspected on June 03-05, 2013 / signed on November 05, 2013
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
23.6 °C
Details on study design: HPLC method:
EQUIPMENT
- Test system: Analytical HPLC-column (based on silica matrix) packed with a cyanopropyl solid phase containing non-polar and polar moieties coupled to DAD. Methanol and HPLC water in a ratio 55 : 45 was used as mobile phase.
- HPLC-DAD system HPLC AGILENT 1100 consisting of:
Auto sampler : G1329A
Auto sampler thermostat : G1330B
Degasser . G1322A
Column oven : G1316A
Detector (test system) . G1315B
Pump : G1312A
Software " Empower 2 (Build No: 2154), WATERS
- HPLC column: YMC-Pack Cyano, 250 x 4.0 mm, S-5 μm, 12 nm, batch 11334, YMC EUROPE GMBH

MOBILE PHASES
- Methanol : HPLC water (55 : 45)
This mobile phase allowed the determination of the adsorption coefficient (Koc) for the test item in a reasonable period with suitable chromatographic properties for the test and reference items. No buffer was used because the adsorption coefficient (Koc) of the test item is independent on the pH value for this test item.
- Column temperature: 20 - 25 °C
- System Suitability: The suitability of the column was confirmed according to the guidelines by the data given below: log k' > 0 for log Koc = 3.02 (Endosulfan-diol) and log k' > -0,4 for log Koc = 1.95 (3-Nitrobenzamide) by using methanol/water 55/45 % as mobile phase.

DETERMINATION OF DEAD TIME
- Method: NaNO3 was used for determination of dead time.

REFERENCE SUBSTANCES
- Identity: Acetanilide, Atrazine, Monuron, Linuron, Phenyl benzoate, Fenthion and Phenanthrene

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: Single (three injections) Stock solution: 200 mg/L in methanol; Test concentration: 110 mg/L; Dilution: With HPLC water to mobile phase ratio
- Quantity of reference substances: Two injections (one before and one after the analysis of the test item); Three injections for NaNO3 at the beginning of the sample set. Stock solution: 100 mg/L each in methanol; 100 mg/L in HPLC-water for NaNO3; Test concentration: 5 mg/L; Dilution: With methanol and HPLC water to mobile phase ratio
- Calibration: Calibrations were performed using seven reference items for soil and six for sewage sludge with known log Koc values.

TYPE AND FREQUENCY OF MEASUREMENT:
Analyses of test item was carried out by HPLC-DAD. The test and reference items were dissolved in methanol, diluted to mobile phase ratio and injected into the HPLC-DAD system.
The retention times were determined. The temperature was recorded during the whole study.

CONDITIONS OF ANALYSIS
CONDITIONS OF ANALYSIS
Injection volume: 10 μL
Mobile phase: Methanol : HPLC water (55 : 45)
Flow: 0.8 mL/min
Wavelength: 287, 210, 240, 220, 245, 245, 235, 250 and 250 for Test iitem, Sodium nitrate, Acetanilide, Atrazine, Monuron, Linuron, Phenyl benzoate, Fenthion and Phenanthrene, respectively
Run time: 20 minutes for test item, Fenthion and Phenanthrene; 10 minutes for the others

EVALUATION
- Calculation of capacity factors k': (tR-t0)/t0
- Determination of the log Koc value: log Koc = a ' log k' + b
Two individual log Koc values for soil and for sewage sludge for the test item were derived under consideration of the first and second calibration. Finally a mean value for soil and for sewage sludge was calculated from, these individual log Koc values.
tR Retention time [min]
to Dead time [min]
k' Capacity factor
a: slope of the calibration graph
b: y-intercept of calibration graph
Finally, a mean value was calculated from these individual log Koc values.
Key result
Type:
log Koc
Remarks:
soil
Value:
2 dimensionless
Temp.:
23.6 °C
Matrix:
silica matrix
Remarks on result:
other: log Koc for the first peak
Key result
Type:
log Koc
Remarks:
soil
Value:
2.3 dimensionless
Temp.:
23.6 °C
Matrix:
silica matrix
Remarks on result:
other: log Koc for the second peak
Key result
Type:
log Koc
Remarks:
sewage sludge
Value:
2 dimensionless
Temp.:
23.6 °C
Matrix:
silica matrix
Remarks on result:
other: log Koc for the first peak
Key result
Type:
log Koc
Remarks:
sewage sludge
Value:
2.5 dimensionless
Temp.:
23.6 °C
Matrix:
silica matrix
Remarks on result:
other: log Koc for the second peak
Details on results (HPLC method):
- Dead Time of the HPLC-System: The HPLC dead time (to) was determined by threefold injection of a solution of 5 mg/L NaNO3. Dead time of the HPLC system: 1.606 ± 0.001
- Retention times of reference substances used for calibration: See table 5.4.1/1
- Average retention data for test substance: See table 5.4.1/3
Results of Test Item Analysis:
For each peak two individual log Koc values for soil and for sewage sludge for the test item were derived under consideration of the first and second calibration. Finally a mean value for soil and for sewage sludge was calculated from these individual log KOC values.
Soil:
For the first peak an individual log KOC value of 2.0 ± 0.1 (95 % CI 1.6 to 2.4) was obtained with both calibrations. The individual values did not differ more than ± 0.25 log KOC values. Based on these data a mean value of 2.0 was derived.
For the second peak an individual log KOC value of 2.3 ± 0.1 (95 % CI 2.0 to 2.7) was obtained with both calibrations. The individual values did not differ more than ± 0.25 log KOC values. Based on these data a mean value of 2.3 was derived.
Sewage Sludge
For the first peak an individual log Koc value of 2.0 ± 0.2 (95 % CI 1.5 to 2.5) was obtained with both calibrations. The individual values did not differ more than ± 0.25 log Koc values. Based on these data a mean value of 2.0 was derived.
For the second peak an individual log Koc value of 2.5 ± 0.2 (95 % CI 2.0 to 2.9) was obtained with both calibrations. The individual values did not differ more than ± 0.25 log Koc values. Based on these data a mean value of 2.5 was derived.

Table 5.4.1/1: Capacity Factors (k') of the Reference Items for Soil and Sewage Sludge

 

Reference item

Log Koc,

soil

Log Koc,

sewage

sludge

1.calibration

2.calibration

tR1 (min)

K’

Log k’

tR2 (min)

K’

Log k’

Acetanilide

1.26

1.52

4.073

1.536

0.186

4.076

1.538

0.187

Atrazine

1.81

1.66

4.743

1.953

0.291

4.749

1.957

0.292

Monuron

1.99

1.46

5.073

2.159

0.334

5.078

2.162

0.335

Linuron*

2.59

2.43

7.951

3.951

0.597

7.968

3.961

0.598

Benzoic

Acid phenylester

2.87

3.26

7.671

3.776

0.577

7.689

3.788

0.578

Fenthion

3.31

3.75

13.068

7.137

0.854

13.100

7.157

0.855

Phenanthrene

4.09

4.35

12.302

6.660

0.823

12.322

6.672

0.824

tR1 = Retention time 1. Injection; tR2 = Retention time 2. Injection

k' = Capacity factor; Koc = Adsorption coefficient

*not used for determination of tR for sewage sludge

 

 

Table 5.4.1/2: Calibration Data of the Reference Items for Soil and Sewage Sludge

Parameters

Soil

Sewage sludge

1.calibration

2.calibration

1.calibration

2.calibration

Slope

3.518

3.518

4.308

4.308

Intercept

0.7197

0.7162

0.4657

0.4614

r2

0.9120

0.9120

0.9225

0.9225

r

0.9550

0.9550

0.9605

0.9605

r : Correlation Coefficient; r2: Coefficient of determination

Table 5.4.1/3: Retention Times, Capacity Factors (k') and Adsorption Coefficient (Koc) of Test item for Soil and Sewage sludge

 

Test item

tR

(min)

K’

Log k’

log Koc soil with 95% CI

1.calibration

2.calibration

Soil - Peak 1

Test item

5.296

2.298

0.3614

2.0 ± 0.1

1.6 to 2.4

2.0 ± 0.1

1.6 to 2.4

5.297

2.298

0.3614

5.298

2.299

0.3615

Mean

5.297

2.298

0.3614

2.0

Soil - Peak 2

Test item

6.266

2.902

0.4627

2.3 ± 0.1

2.0 to 2.7

2.3 ± 0.1

2.0 to 2.7

6.267

2.902

0.4627

6.269

2.903

0.4628

Mean

6.267

2.902

0.4627

2.3

Sewage sludge - Peak 1

Test item

5.296

2.298

0.3614

2.0 ± 0.2

1.5 to 2.5

2.0 ± 0.2

1.5 to 2.5

5.297

2.298

0.3614

5.298

2.299

0.3615

Mean

5.297

2.298

0.3614

2.0

Sewage sludge - Peak 2

Test item

6.266

2.902

0.4627

2.5 ± 0.2

2.0 to 2.9

2.5 ± 0.2

2.0 to 2.9

6.267

2.902

0.4627

6.269

2.903

0.4628

Mean

6.267

2.902

0.4627

2.5

 

tR = Retention time

CI = Confidence Interval

 

Validity Criteria

The validity criteria were fulfilled:

A signal-to-noise ratio > 3 was provided for NaNO3, reference and the test items.

The value of logKocderived from repeated measurements made under identical conditions and using the same set of reference items fell within a range of ± 0.25 log units.

The column temperature during the measurement was kept in the range of 20-25 ± 1 °C and did not differ more than ± 1 °C.

Validity criteria fulfilled:
yes
Conclusions:
The adsorption coefficient log Koc of the test item was determined to be 2.0 for the first peak and 2.3 for the second peak in soil and 2.0 for the first peak and 2.5 for the second peak in sewage sludge.
Executive summary:

The adsorption coefficient (log Koc) for the test item on soil and on sewage sludge using high performance liquid chromatography (HPLC) was estimated according to OECD 121 guideline with GLP compliance.

 

The test was performed temperature controlled, (23.6 °C, mean value) with a mobile phase consisting of 55 % methanol and 45 % HPLC water. A 110 mg/L sample of the test item was analyzed threefold via HPLC on a cyanopropyl (CN-) column with DAD-detection.

 

Calibrations were performed using seven reference items for soil and six for sewage sludge with known log Koc values (given by the guidelines). The reference items were measured twice, once before and once after the measurement (double injection of one replicate) of the test item. Dead time of the HPLC- system was determined with sodium nitrate.

 

For each peak two individual log Koc values for soil and for sewage sludge for the test item were derived under consideration of the first and second calibration. Finally a mean value for soil and for sewage sludge was calculated from these individual log Koc values. Based on these data a log Koc of 2.0 for the first peak and 2.3 for the second peak for soil and a log Koc 2.0 for the first peak and 2.5 for the second peak for sewage sludge were determined for test item.

 

The adsorption coefficient log Koc of the test item was determined to be 2.0 for the first peak and 2.3 for the second peak in soil and 2.0 for the first peak and 2.5 for the second peak in sewage sludge.

Description of key information

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

log Koc = 2.0 and 2.3 for soil (Koc=100 and 199)

log Koc= 2.0 and 2.5 for sewage sludge (Koc=100 and 316)

The substance is considered moderately mobile in soils and sewage sludge (according to the criteria developed by P.J. McCall et al., 1981).

Key value for chemical safety assessment

Koc at 20 °C:
316

Additional information