Registration Dossier

Environmental fate & pathways

Adsorption / desorption

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
23-07-2019 to 06-12-2019
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study performed under GLP. All relevant validity criteria were met.
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
Type of method:
HPLC estimation method
Media:
soil/sewage sludge
Radiolabelling:
no
Test temperature:
35 ± 1 °C
Details on study design: HPLC method:
EQUIPMENT
- Apparatus: Acquity UPLC system with PDA detector
- Type: Acquity UPLC HSS Cyano 1.8μm (100 x 2.1 mm id)
- Type, material and dimension of analytical (guard) column: None reported.
- Detection system: PDA/UV-diode array detection, 210 nm wavelength

MOBILE PHASES
- Type: Methanol : purified water (55:45 v/v) Flow Rate 0.4 mL per minute. At 35 ± 1 °C.
- Experiments with additives carried out on separate columns: No
- pH: mobile phase: pH = approximately neutral. Prior to testing within preliminary assessment: the pKa values of the test item were calculated using the Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International, USA). Based on the calculations, and an absence of relevant dissociating groups within the range of pH 5.5 to 7.5 the HPLC method was performed at neutral pH.
- Solutes for dissolving test and reference substances: None.

DETERMINATION OF DEAD TIME
- Method: The dead time was determined by measuring the retention time of formamide (purity: 99%, as certified by supplier), 5 g/L stock solution in methanol diluted into methanol : purified water (55:45 v/v). Determined in duplicate.

REFERENCE SUBSTANCES
- Identity: Acetanilide, CAS 103-84-4, Purity 99%+, log Koc 1.26 (OECD Guideline 121)
- Identity: Munuron, CAS 150-68-5, Purity 99.9%, log Koc 1.99 (OECD Guideline 121)
- Identity: 2,5-Dichloroaniline, CAS 95-82-9, Purity 99.9%, log Koc 2.55 (OECD Guideline 121)
- Identity: Benzoic acid phenylester, CAS 93-99-2, Purity 99.9%+, log Koc 2.87 (OECD Guideline 121)
- Identity: Fenthion, CAS 55-38-9, Purity 98.6%, log Koc 3.31 (OECD Guideline 121)
- Identity: Phenanthrene, CAS 85-01-8, Purity 98.5%, log Koc 4.09 (OECD Guideline 121)
- Identity: DDT, CAS 50-29-3, Purity 99.3%, log Koc 5.63 (OECD Guideline 121)

DETERMINATION OF RETENTION TIMES
- Quantity of test substance introduced in the column: 5 μL per injection; an aliquot of test item (100 mg/L) was introduced in duplicate..
- Quantity of reference substances: 5 μL per injection; the concentration introduced of each reference substance injected in duplicate was not reported.
- Intervals of calibration: The calibration was performed once specific for the study; with a range of log Koc suitable for the test item estimation of adsorption to sewage sludge and soil under EU Method C.11 and OECD TG 121 guidelines.

REPETITIONS
- Number of determinations: Two.

EVALUATION
- Calculation of capacity factors k': Calculated as a ratio of retention time of retained compounds relative to unretained substances after determination of the column dead time.
- Calculation of retention times: Determined empirically relative to the known column dead time.
- Determination of the log Koc value: Capacity factors (log k') for reference substances were plotted against absorption coefficients (log Koc). The log Koc for the test item was then calculated using the resultant equation for the calibration curve and the experimentally determined log k'.
Key result
Type:
log Koc
Value:
ca. 2.99 dimensionless
pH:
7
Temp.:
35 °C
Key result
Type:
Koc
Value:
ca. 977 L/kg
pH:
7
Temp.:
35 °C
Details on results (HPLC method):
EVALUATION
- Calculation of capacity factors k': Calculated as a ratio of retention time of retained compounds relative to unretained substances after determination of the column dead time.
- Calculation of retention times: Determined empirically relative to the known column dead time.
- Determination of the log Koc value: Capacity factors (log k') for reference substances were plotted against absorption coefficients (log Koc). The log Koc for the test item was then calculated using the resultant equation for the calibration curve and the experimentally determined log k'.

- Identity: Acetanilide, CAS 103-84-4, ca. 0.952 min
- Identity: Munuron, CAS 150-68-5, ca. 1.181 min
- Identity: 2,5-Dichloroaniline, CAS 95-82-9, ca. 1.366 min
- Identity: Naphthalene, CAS 91-20-3, ca. ca. 1.591 min
- Identity: Benzoic acid phenylester, CAS 93-99-2, ca. 1.878 min
- Identity: Fenthion, CAS 55-38-9, ca. 2.579 min
- Identity: Phenanthrene, CAS 85-01-8, ca. 2.854 min
- Identity: DDT, CAS 50-29-3, ca. 7.232 min

- Dead-Time: ca. 0.716 minutes
- Details of fitted regression line (log k' vs. log Koc): Linear regression of all reference substances; y = 0.327x – 0.8195 , (R = 0.98; n=16)
- Retention data for test substance: Single peak (main constituent). The average retention time; peak : 1.744 minutes (Log Koc = 2.99)
Validity criteria fulfilled:
yes
Conclusions:
The test item adsorption coefficient (log Koc) for soil/sewage sludge according to EU Method C.19 and OECD Guideline 121 was estimated to be log Koc = 2.99 at 35°C and pH 7.0 by UPLC analysis.
Executive summary:

The study was performed to EU Method C.19 and OECD TG 121 to assess the adsorption coefficient (Koc) of the test item in accordance with GLP using a ultra performance chromatography system (UPLC). The retention times of the test item and selected reference items were accurately measured using UPLC fitted with a cyanopropyl column. The retention times were consistent over the course of the study. The dead time of the instrument was also measured, and capacity factors were calculated for each reference substance. Calibration curves were constructed by plotting the capacity factor (log k') for the reference substances against their adsorption coefficients (log Koc). Linear regression analysis was performed, and this showed a reasonable relationship between the capacity factors and the adsorption coefficients. The test was performed at a singular approximately neutral pH as the test item does not possess ionisable moieties in an environmentally relevant pH range. The adsorption coefficient of the test item was estimated using the calibration curve constructed from all reference items. Under the conditions of this study, the test item adsorption coefficient (log Koc) for soil/sewage sludge was estimated to be log Koc 2.99 at 35°C and pH 7.0 by UPLC analysis.

Description of key information

log Koc = 2.99 (and Koc 977 L/kg), 35 °C, ca. pH 7 and 1 atm, EU Method C.19, 2020

Key value for chemical safety assessment

Koc at 20 °C:
977

Additional information

Key study : EU Method C.19, 2020 : The study was performed to EU Method C.19 and OECD TG 121 to assess the adsorption coefficient (Koc) of the test item in accordance with GLP using a ultra performance chromatography system (UPLC). The retention times of the test item and selected reference items were accurately measured using UPLC fitted with a cyanopropyl column. The retention times were consistent over the course of the study. The dead time of the instrument was also measured, and capacity factors were calculated for each reference substance. Calibration curves were constructed by plotting the capacity factor (log k') for the reference substances against their adsorption coefficients (log Koc). Linear regression analysis was performed, and this showed a reasonable relationship between the capacity factors and the adsorption coefficients. The test was performed at a singular approximately neutral pH as the test item does not possess ionisable moieties in an environmentally relevant pH range. The adsorption coefficient of the test item was estimated using the calibration curve constructed from all reference items. Under the conditions of this study, the test item adsorption coefficient (log Koc) for soil/sewage sludge was estimated to be log Koc 2.99 at 35°C and pH 7.0 by UPLC analysis.