2,5-di-tert-pentylhydroquinone

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 June 2010-13 September 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study has been performed according to OECD and EC guidelines and according to GLP principles.

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

GLP compliance:

yes (incl. QA statement)

Type of method:

HPLC estimation method

Media:

other: soil-adsorption-reference data

Details on study design: HPLC method:

The principle of the test method is similar to that of the OECD guideline no. 117: "Partition coefficient (n-octanol/water), high performance liquid chromatography (HPLC) method". While passing through the column along with the mobile phase the test substance interacts with the stationary phase. As a result of partitioning between mobile and stationary phases, the test substance is retarded. The dual composition of a cyanopropyl stationary phase, having polar and non-polar sites allows for interaction of polar and non-polar groups of a molecule in a similar way as is the case for organic matter in soil or sewage sludge matrices. This enables the relationship between the retention time on the column and the Koc on organic matter to be established.

According to the guidelines, the determination of the Koc for test substances that are ionized for at least 10% within pH 5.5 to 7.5 should be performed with both the ionized and non-ionized form. Therefore, the pKa values of the test substance were calculated using the Perrin calculation method (pKalc 5.0, module in Pallas 3.0, CompuDrug International San Francisco, CA, USA). Based on the calculations, the HPLC analysis was performed at neutral pH.

Solutions of reference substances with known log Koc values based on soil adsorption data and the test substance were analysed.

Analytical conditions
Instrument: Alliance Separation Module 2695 (Waters, Milford, MA, USA)
Detector: Dual λ Absorbance Detector 2487 (Waters)
Column: Hypersil BDS-CN, 150 mm x 4.6 mm i.d., dp = 5 µm (Thermo Fisher Scientific, Waltham, MA, USA)
Column temperature: 35°C +/- 1°C
Mobile phase: 55/45 (v/v) methanol/water
Flow: 1 ml/min
Injection volume: 10 µl
UV detection: 210 nm

Preparation of the solutions
Solution of the unretained compound
A 1.14 g/l stock solution of formamide (99.8%, Acros Organics, Geel, Belgium) in methanol was used. The stock solution was diluted to obtain an end solution of 55/45 (v/v) methanol/water. The formamide blank solution was 55/45 (v/v) methanol/water.

Reference substance solutions
Stock solutions of the reference substances at concentrations of approximately 1 g/l in methanol were used. The stock solutions were diluted to obtain an end solution of 55/45 (v/v) methanol/water. The blank solution for the mixture of reference substances was 55/45 (v/v) methanol/water.

Test solution
A 1350 mg/l stock solution of the test substance was prepared in methanol. The stock solution was diluted to obtain an end solution of 55/45 (v/v) methanol/water. The final concentration of the test substance solution was 13.5 mg/l. The test substance blank solution was 55/45 (v/v) methanol/water.

Key result

Type:

log Koc

Value:

3.68 dimensionless

pH:

7

Temp.:

35 °C

Remarks on result:

other: Test substance

Key result

Type:

Koc

Value:

4 800 dimensionless

pH:

7

Temp.:

35 °C

Validity criteria fulfilled:

yes

Conclusions:

The HPLC method using soil-adsorption-reference data was chosen for the determination of the adsorption coefficient of Lowinox® AH25.

The Koc and log Koc value of the test substance at neutral pH were 4.8 x 10E3 and 3.68, respectively.

No impurities with a peak area percentage of > 1% of the total peak area were observed.

Executive summary:

The aim of the study was to determine the following physico-chemical properties for Lowinox® AH25: Adsorption coefficient in accordance with the following guidelines:

Organization for Economic Co-operation and Development (OECD), OECD Guideline for the Testing of Chemicals no. 121: "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)", January 22, 2001.

European Community (EC), EC no. 440/2008, Part C: Methods for the Determination of Ecotoxicity, Guideline C.19: "Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)", Official Journal of the European Union no. L 142, May 31, 2008.

 

The HPLC method using soil-adsorption-reference data was chosen for the determination of the adsorption coefficient of Lowinox® AH25.

 

The Koc and log Koc value of the test substance was:

Test substance	Neutral pH
	Koc	Log Koc
	4.8 x 10^3	3.68

 

No impurities with a peak area percentage of > 1% of the total peak area were observed.

Reference 2

Endpoint:

adsorption / desorption, other

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 Jun 2019 to 18 Dec 2020

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method)

Version / remarks:

OECD Guideline 106. Adsorption-Desorption using a Batch Equilibrium Method. 21 January 2000.

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

other: EU no. 544/2011

Version / remarks:

EU no. 544/2011 Implementing Regulation EC no. 1107/2009 of the European Parliament and of the Council as Regards the Data Requirements for Active Substances. 10 June 2011.

Deviations:

not specified

Qualifier:

according to guideline

Guideline:

EPA OPPTS 835.1110 (Activated Sludge Sorption Isotherm)

Version / remarks:

US-EPA Office of Prevention, Pesticides and Toxic Substances. Fate, Transport and Transformation Test Guideline OPPTS 835.1110: Activated Sludge Sorption Isotherm. January 1998.

Deviations:

not specified

GLP compliance:

yes

Type of method:

batch equilibrium method

Media:

other: Speyer 2.2, Speyer 2.3 and Speyer 6S soil and Tilburg and Aa & Maas sludges

Specific details on test material used for the study:

Identification: [phenyl-U-14C]LOWINOX AH25
Batch (Lot) Number: 10532JLM009-8; 11800VXL001-2
Expiry date: Not indicated ; Not indicated
Physical Description: White solid ; White solid
Radiochemical purity: 97.8 area% 99.1 %
Chemical purity: 95.6 area% 99.2 %
Specific activity: 5.02 MBq/mg (1262 MBq/mmol); 4.70 MBq/mg (1181 MBq/mmol)
Storage Conditions: In freezer (≤ -15°C) In ultra-low freezer (≤ 75°C) Protected from light.
Store dry (e.g. store in a bag of silica)
Supplier: Selcia Limited, Fyfield Business and Research Park, Fyfield Road, Ongar, Essex, CM5 0GS, UK

Additional information
Test Facility Test Item Number: 210342/A 210342/B
Purity/Composition correction factor: No correction factor required
Test item handling: No specific handling conditions required.
Molecular formula: C16H26O2
Molecular weight: 251.47 g/mol (at this specific activity); 251.40 g/mol (at this specific activity)

Justification for Position and Type of Labelling
Carbon-14 is the isotope of choice in environmental fate studies.
The radiochemical purity of the radiolabeled test item was determined by the supplier and was verified at the Test Facility at the start of the experiment.

Unlabeled Test Item
Identification: Lowinox ® AH25
Batch (Lot) Number: WAH8E0007
Expiry date: 07 May 2022 (retest date)
Physical Description: White to cream colored powder
Purity/Composition: 95.88%
Storage Conditions: At room temperature

Radiolabelling:

yes

Remarks:

Carbon-14

Test temperature:

20 ± 2°C in the dark

Analytical monitoring:

yes

Details on sampling:

During method development of soil and sludge different extraction solvents were tested. The extraction solvent with the best efficiency was chosen for further development. A concentration step was tested where the extraction solvent was concentrated to approximately 1.5 mL.

Matrix no.:

#1

Matrix type:

loamy sand

% Clay:

8.3

% Silt:

14.9

% Sand:

76.8

% Org. carbon:

1.73

pH:

5.6

CEC:

9.8 meq/100 g soil d.w.

Matrix no.:

#2

Matrix type:

loamy sand

% Clay:

8.9

% Silt:

13.9

% Sand:

77.2

% Org. carbon:

1.61

pH:

5.6

CEC:

8.5 meq/100 g soil d.w.

Matrix no.:

#3

Matrix type:

sandy loam

% Clay:

7.3

% Silt:

33.3

% Sand:

59.4

% Org. carbon:

0.65

pH:

6.1

CEC:

6.8 meq/100 g soil d.w.

Matrix no.:

#4

Matrix type:

clay

% Clay:

40.8

% Silt:

35.1

% Sand:

24.1

% Org. carbon:

1.78

pH:

7.2

CEC:

25.7 meq/100 g soil d.w.

Matrix no.:

#5

Matrix type:

clay

% Clay:

40.9

% Silt:

35.5

% Sand:

23.8

% Org. carbon:

1.78

pH:

7.2

CEC:

24.2 meq/100 g soil d.w.

Matrix no.:

#6

Matrix type:

clay

% Clay:

79

% Silt:

21

% Sand:

0

% Org. carbon:

44.1

pH:

6

CEC:

121 meq/100 g soil d.w.

Matrix no.:

#7

Matrix type:

clay

% Org. carbon:

33.6

pH:

6.3

CEC:

116 meq/100 g soil d.w.

Matrix no.:

#8

Matrix type:

clay

% Org. carbon:

35.6

pH:

5.6

CEC:

41.2 meq/100 g soil d.w.

Details on matrix:

Adsorption and desorption parameters of the test item were determined in three different soils and in two different sludges. Sieved (2 mm) air-dried soil samples and sieved (2 mm) freezedried and oven-dried sludge samples were taken from storage. Storage was at ambient temperature and did not exceed three years after sampling for the soils and one year after sampling or reanalysis for the sludges. Moisture content was determined after oven drying until constant weight. Soil and sludge parameters are summarized in the table form and detailed characteristics are given in table form - see "Any other information" for details.

Details on test conditions:

Performance of the Adsorption/Desorption Study
Confirmation of Identity of 14C-Labeled Test Item
To confirm the identity of the 14C-labeled test item a 14C-labeled stock solution and unlabeled stock solution were prepared in acetonitrile. Both stock solution were analyzed with LC.

Moisture Content
The moisture content was determined by oven-drying at approximately 105°C for 2 to 4 days for the Speyer 2.2, Speyer 2.3 and Speyer 6S soils and for 8 to 17 days for the Tilburg and Aa & Maas sludges, prior to start of the study. For all calculations, the weight of soil or sludge was corrected for moisture content.

Solubility Test
The solubility of [14C]-test item in 0.01M calcium chloride (CaCl2) solution was investigated up to 10 mg/L. If the test item is not readily soluble in 0.01M CaCl2 then use of a co-solvent up to 0.1% (v/v) may be investigated. Results of these experiments will determine the test concentration for the remainder of the study.

Preliminary Test
Soil:solution ratio of 1:2, 1:10 and 1:50, sludge:solution ratio of 1:100 and 1:500 and stability/adsorption
A spike solution of the test item in acetonitrile was used at a level of 120 kBq/mL (based on triplicate analysis by LSC; RSD 1.9%). This is equivalent to a test item concentration of 23.9 mg/L. The radiochemical purity of the test item in the stock solution was determined by LC-analysis at the start of the test.
At the start, middle and at the end of the spiking procedure, the same amount of spike solution was pipetted in LSC vials. LSC analysis indicated that the concentration in the test systems was between 0.0504 and 0.0508 mg/L (based on triplicate analysis by LSC of 0.094 mL aliquots; RSD 0.2%).
Soil:solution ratio of 1:100 and 1:200 and sludge:solution ratio of 1:1000
A spike solution of the test item in acetonitrile was used at a level of 120 kBq/mL (based on triplicate analysis by LSC; RSD 1.6%). This is equivalent to a test item concentration of 23.8 mg/L. The radiochemical purity of the test item in the stock solution was determined by LC-analysis at the start of the test.
At the start, middle and at the end of the spiking procedure, the same amount of spike solution was pipetted in LSC vials. LSC analysis indicated that the concentration in the test systems was between 0.0534 and 0.0541 mg/L (based on triplicate analysis by LSC of 0.095 mL aliquots; RSD 0.8%).

Stability/adsorption with glass container rinsed with an unlabeled test item solution
A spike solution of the test item in acetonitrile was used at a level of 1.02 MBq/mL (based on triplicate analysis by LSC; RSD 1.1%). This is equivalent to a test item concentration of 204 mg/L. The radiochemical purity of the test item in the stock solution was determined by LC-analysis at the start of the test.
At the start, middle and at the end of the spiking procedure, the same amount of spike solution was pipetted in LSC vials. LSC analysis indicated that the concentration in the test systems was 0.050 mg/L (based on triplicate analysis by LSC of 0.011 mL aliquots; RSD 1.4%).

Stability of Test Item / Adsorption to Container Material
To test the adsorption of the test item to test container walls and the stability in 0.01 M CaCl2 solution, the test solution was incubated in polypropylene vials and glass containers (duplicate samples) on a roller mixer at 20 ± 2°C in the dark for 48 hours. The initial test item concentration was approximately 0.05 mg/L. Radioactivity was determined in a 100 μL aliquot by LSC after 3, 6, 24 and 48 hours. Additionally, subsamples were taken for LCanalysis at all time points.

Stability of Test Item / Adsorption to Container Material rinsed with an unlabeled test item solution
To test the adsorption of the test item to test container walls and the stability in 0.01 M CaCl2 solution, the test solution was incubated in glass containers, which were rinsed with an unlabeled test item solution, (duplicate samples) on a roller mixer at 20 ± 2°C in the dark for 48 hours. The initial test item concentration was approximately 0.05 mg/L. Radioactivity was determined in a 100 μL aliquot by LSC after 24 and 48 hours. Additionally, subsamples were taken for LC-analysis at both time points.

Determination of an Appropriate Test System:Solution Ratio
Soil:solution ratios of 1:2, 1:10, 1:50, 1:100 and 1:200 were investigated for Speyer 2.2 and Speyer 6S soil in order to determine an appropriate ratio for the kinetics and isotherm experiments. Approximately 30 mL of 0.01 M CaCl2 solution were added to 15 g soil for a soil:solution ratio of 1:2, 45 mL of 0.01 M CaCl2 solution to 4.5 g soil for a ratio of 1:10, 45 mL of 0.01 M CaCl2 solution to 0.9 g soil for a ratio of 1:50, 45 mL of 0.01 M CaCl2 solution to 0.45 g soil for a ratio of 1:100 and 45 mL of 0.01 M CaCl2 solution to 0.225 g soil for a ratio of 1:200.
Sludge:solution ratios of 1:100, 1:500 and 1:1000 were tested for Tilburg sludge in order to determine an appropriate ratio for the kinetics and isotherm experiments. Approximately 45 mL of 0.01 M CaCl2 solution was added to 0.45 g sludge for a sludge:solution ratio of 1:100, 45 mL of 0.01 M CaCl2 solution to 0.09 g sludge for a ratio of 1:500 and 45 mL of 0.01 M CaCl2 solution to 0.045 g sludge for a ratio of 1:1000.
The soils with soil:solution ratios of 1:2, 1:10 and 1:50 and sludges with sludge:solution ratios of 1:100 and 1:500 were equilibrated in polypropylene tubes on a roller mixer at 20 ± 2°C in the dark overnight. After equilibration, the samples were spiked with 63 μL (1:2 ratio) and 94 μL (other ratios) stock solution. The initial test item concentration was approximately 0.05 mg/L.
The soils with soil:solution ratios of 1:100 and 1:200 and sludges with sludge:solution ratio of 1:1000 were equilibrated in glass containers on a roller mixer at 20 ± 2°C in the dark overnight. After equilibration, the samples were spiked with 95 μL stock solution. The initial test item concentration was approximately 0.05 mg/L.
The samples were placed on a roller mixer at 20 ± 2°C in the dark. After 24 hours of contact time, the containers were removed from the roller mixer and centrifuged for 5 minutes at 3000 g and 20°C or 15 minutes at 160 g and 20°C. Aliquots of 100 μL were taken for LSC
analysis. Additionally, sub-samples were taken for LC analysis.
After removal of the supernatant, at the end of the adsorption phase of the soil:solution ratio 1:2 and 1:100 and sludge:solution ratio 1:100 and 1:1000, the slurries were extracted three times for 10 minutes with 10 mL acetonitrile on a shaker at 250 rpm. Centrifuged for 5 minutes at 3000 g and 20°C or 15 minutes at 160 g and 20°C and activity was determined in the extracts using LSC. Extracts were also analyzed by LC.

Determination of Equilibrium Time (Adsorption and Desorption Kinetics)
The initial determination of the adsorption and desorption kinetics was performed in July 2020 with test item 210342/A batch 10532JLM009-8. The mass balances after adsorption and desorption were low, due to the volatile properties of the test item. Since test item was observed to have been degraded before addition to the kinetics system it was decided to repeat kinetics using new test item. The kinetic experiment was repeated with a new batch test item, 210342/B batch 11800VXL001-2 in October 2020.
A stock solution of the test item in acetonitrile at a level of 109 kBq/mL (based on triplicate analysis by LSC; RSD 1.1%) was used. This is equivalent to a test item concentration of 23.3 mg/L. The radiochemical purity of the test item in the stock solution was determined by LC-analysis at the start of the test.
A soil:solution ratio of 1:200 and sludge:solution ratio of 1:1000 was selected. The soils (approximately 0.225 g soil and 45 mL 0.01 M CaCl2 solution) and the sludges (approximately 0.045 g sludge and 45 mL 0.01 M CaCl2 solution) were equilibrated in glass vials on a roller mixer at 20 ± 2°C overnight in the dark prior to spiking. The adsorption-desorption kinetics experiment was initiated by adding a volume of 38.7 μL stock solution to the pre-equilibrated slurries. Hence, the initial concentration of the test item in the solution was approximately 0.02 mg/L.
At the begin, middle and at the end of the spiking procedure, the same amount of spike solution was pipetted in LSC vials. LSC analysis indicated that the concentration in the test systems was 0.0201 mg/L (based on triplicate analysis by LSC of 0.0387 mL aliquots; RSD 0.2%).
Because of the required extraction of the soil and sludge samples after every time point, samples were prepared in parallel. Four samples were prepared for the adsorption test and 4 samples for the desorption test for every soil and sludge type. At each sampling time, one sample was sacrificed for the determination of the mass balance. A blank sample was included for each test system using the same amounts of soil/sludge and 0.01 M CaCl2 solution without test item. Two control samples were also included, containing known amounts of 0.01 M CaCl2 solution and spike solution without a test system.
The samples were placed on a roller mixer at 20 ± 2°C in the dark. At the adsorption sampling times (3, 6, 24 and 48 hours), the soil and sludge suspensions were removed from the roller mixer and centrifuged for 15 minutes at 160 g and 20°C. After centrifugation, a 1 mL aliquot of the supernatant was taken from each sample (including blanks) for determination of activity by LSC. Directly after sampling, the test systems, all but one for the determination of the mass balance at that sampling time point, were mixed well and placed back on the roller mixer until the next sampling event. After 48 hours of adsorption, the remaining supernatant of each test system was decanted and weighed.
Subsequently, an approximately equal weight of fresh 0.01 M CaCl2 solution was added to the test systems. The vials were closed and placed on the roller mixer. At the desorption sampling times (3, 6, 24 and 48 hours), the soil and sludge suspensions were removed from the roller mixer and centrifuged (15 minutes at 160g and 20°C). After centrifugation, a 1 mL aliquot of the supernatant was taken from each sample for the determination of activity by LSC. After the final desorption sampling event, the remaining supernatant was decanted and weighed.
The decanted supernatants (after both the adsorption and the desorption phase) were analyzed by LC. The pH of the supernatants after the adsorption and desorption phase of the kinetics experiment (one replicate of each test system) was determined on the day of decanting.
After removal of the supernatant at the end of the adsorption and desorption phase, the slurries were extracted using the developed extraction method and activity was determined in the extracts using LSC. Extracts were also analyzed by LC. After extraction the remaining slurries were allowed to dry to the air at room temperature for 5 - 9 days.
The adsorption part was started in eight-fold for each test system with an in duplicate measurement of the activity in 0.01 M CaCl2 (replicate E and F). The desorption part was conducted with single replicates measurement of the activity is 0.01M CaCl2 (replicate F only). Mass balances were determined after each sampling point at the adsorption part (replicate E) and after each sampling point at the desorption part (replicate F) for each test system. Mass balances included radioactivity in samples taken for analysis, radioactivity in decanted supernatant after adsorption and/or desorption, radioactivity determined after extraction and radioactivity in test system.

Determination of Adsorption/Desorption Isotherms
A stock solution was prepared in acetonitrile at a concentration of 719 kBq/mL labeled test item. This is equivalent to a concentration of 153 mg/L.
A spike solution was prepared by diluting the stock solution with acetonitrile, resulting in a concentration of 7.01 kBq/mL labeled test item (based on triplicate analysis by LSC; RSD 1.0 %). This is equivalent to a concentration of 1.49 mg/L. This spike solution was used to spike the 0.001 and 0.004 mg/L test systems. Another spike solution was also prepared by diluting the stock solution with acetonitrile, resulting in a concentration of 132 kBq/mL labeled test item (based on triplicate analysis by LSC; RSD 1.4 %). This is equivalent to a concentration of 28.0 mg/L. This spike solution was used to spike the 0.02, 0.04 and 0.1 mg/L test systems.
The radiochemical purity of the test item in the stock solution was determined by LC-analysis at the start of the test.
At the begin, middle and at the end of the spiking procedure, the same amount of spike solution was pipetted in LSC vials.
Sludge suspensions (sludge:solution ratio of 1:1000) in glass containers were equilibrated on a roller mixer at 20 ± 2°C overnight in the dark prior to spiking. A blank sample was included for each test system using a known amount of 0.01 M CaCl2 solution and no test item. Two
control samples for each test system were also included, containing known amounts of 0.01 M CaCl2 solution and spike solution but without sludge. The adsorption-desorption isotherms experiment was initiated by adding the spike volume to the fifteen pre-equilibrated sludge slurries (three replicates per concentration). Initial test item concentrations of approximately 0.001, 0.0040, 0.0192, 0.0409 and 0.101 mg/L were obtained.
The samples were incubated on a roller mixer at 20 ± 2°C in the dark. After 24 hours of contact time, the sludge suspensions were removed from the roller mixer and centrifuged for 10 minutes at 500 g and 20°C. The activity in 10 mL (target concentration 0.001 and 0.004 mg/L) or 1 mL (target concentration 0.02, 0.04 and 0.1 mg/L) of supernatant was determined by LSC. The supernatants were decanted and weighed.
For one sample of each concentration, the sludge after decantation as extracted using the developed extraction method and activity was determined in the extracts using LSC. Extracts were also analyzed by LC. After extraction the remaining slurries were dried at room temperature for 6 - 7 days.
For the remaining samples, decanted supernatant was replaced by an approximately equal, known volume of fresh 0.01 M CaCl2 solution. The suspensions were mixed well and placed on a roller mixer at 20 ± 2°C for 24 hours. The suspensions were centrifuged for 10 minutes at 500 g and 20°C. The activity in 10 mL (target concentration 0.001 and 0.004 mg/L) or 1 mL (target concentration 0.02, 0.04 and 0.1 mg/L) of supernatant was determined by LSC.
The adsorption and desorption parts of the isotherms experiments were conducted in triplicate for each test system. The pH of the supernatants after the adsorption and desorption parts of the experiment (one replicate of highest and lowest concentration of each test system) was determined after decanting.

Computational methods:

Critical computerized systems used in the study are listed under "Any other information". All computerized systems used in the conduct of this study have been validated; when a particular system has not satisfied all requirements, appropriate administrative and procedural controls were implemented to assure the quality and integrity of data.

Key result

Sample No.:

#1

Type:

other: KF,ocads

Value:

8 308 other: ml/g

Temp.:

20 °C

Matrix:

Tilburg Clay

% Org. carbon:

33.6

Key result

Sample No.:

#2

Type:

other: KF,ocads

Value:

10 441 other: ml/g

Temp.:

20 °C

Matrix:

Aa & Maas Clay

% Org. carbon:

35.6

Details on results (HPLC method):

N/A

Recovery of test material:

The spike solution prepared for the performance check had a radiochemical purity of 98.4%.
In 2 extraction steps, 97.7%, 96.5%, and 100% of applied radioactivity was extracted from Speyer 2.2, Speyer 2.3and Speyer 6S soil and 98.7% and 98.1% for Tilburg and Aa & Maas sludge, respectively. In the final concentrated extracts 94.9%, 90.6%, and 93.6% of applied radioactivity was recovered for Speyer 2.2, Speyer 2.3 and Speyer 6S soil and 98.1% and 97.9% for Tilburg and Aa & Maas sludge, respectively. The procedural recoveries for the concentration steps were in the acceptable range of 90-110%.
LC analysis (50 μL injections) indicated that in the concentrated extract 70.5% (Speyer 2.2), 65.9% (Speyer 2.3), 20.3% (Speyer 6S), 66.1% (Tilburg) and 50.8% (Aa & Maas) C14-Lowinox ® AH 25 was present. Test item is know to degrade in solution into the transformation product 2,5-di-tert-amylbenzoquinone, which is observed to be volatile. Calculations on limit of detection and limit of quantification are based on the test item data without inclusion of the transformation product. Total recovery is based on the recovery of the test item and the transformation product.
The limit of detection was 4.3% (Speyer 2.2), 3.7% (Speyer 2.3), 4.1% (Speyer 6S), 2.5% (Tilburg) and 2.0% (Aa & Maas) of applied radioactivity. The limit of quantification was 6.7% (Speyer 2.2), 7.7% (Speyer 2.3), 6.2% (Speyer 6S), 5.5% (Tilburg) and 2.7% (Aa & Maas) of applied radioactivity.

Concentration of test substance at end of adsorption equilibration period:

The graphs show that for all soils, adsorption no equilibrium was reached. The amount of test item adsorbed to soil after 48 hours of contact time was 88.7% (Speyer 2.2), 93.8% (Speyer 2.3) and 93.7% (Speyer 6S). For both sludges, adsorption equilibrium was reached after approximately 24 hours. The amount of test item adsorbed to sludge after 48 hours of contact time was 77.5% (Tilburg) and 81.4% (Aa & Maas).
The graphs show that for soil no equilibrium was reached.

Concentration of test substance at end of desorption equilibration period:

Desorption equilibrium for all soils and both sludges was reached after approximately 24 hours.
Based on the results of this experiment, it was decided to take samples after 24 hours of adsorption and after 24 hours desorption in the sludge isotherms experiment.

Sample no.:

#1

Duration:

48 h

% Adsorption:

88.7

Sample no.:

#3

Duration:

48 h

% Adsorption:

93.8

Sample no.:

#4

Duration:

48 h

% Adsorption:

93.7

Sample no.:

#6

Duration:

48 h

% Adsorption:

77.5

Sample no.:

#8

Duration:

48 h

% Adsorption:

81.4

Sample no.:

#1

Duration:

48 h

% Desorption:

32

Sample no.:

#3

Duration:

48 h

% Desorption:

23

Sample no.:

#4

Duration:

48 h

% Desorption:

24

Sample no.:

#6

Duration:

48 h

% Desorption:

84

Sample no.:

#8

Duration:

48 h

% Desorption:

84

Transformation products:

yes

Remarks:

2,5-di-tert-amylbenzoquinone

Details on results (Batch equilibrium method):

Method development and performance check
The spike solution prepared for the performance check had a radiochemical purity of 98.4%.
In 2 extraction steps, 97.7%, 96.5%, and 100% of applied radioactivity was extracted from Speyer 2.2, Speyer 2.3and Speyer 6S soil and 98.7% and 98.1% for Tilburg and Aa & Maas sludge, respectively. In the final concentrated extracts 94.9%, 90.6%, and 93.6% of applied radioactivity was recovered for Speyer 2.2, Speyer 2.3 and Speyer 6S soil and 98.1% and 97.9% for Tilburg and Aa & Maas sludge, respectively. The procedural recoveries for the concentration steps were in the acceptable range of 90-110%.
LC analysis (50 μL injections) indicated that in the concentrated extract 70.5% (Speyer 2.2), 65.9% (Speyer 2.3), 20.3% (Speyer 6S), 66.1% (Tilburg) and 50.8% (Aa & Maas) C14- Lowinox ® AH 25 was present. Test item is know to degrade in solution into the transformation product 2,5-di-tert-amylbenzoquinone, which is observed to be volatile. Calculations on limit of detection and limit of quantification are based on the test item data without inclusion of the transformation product. Total recovery is based on the recovery of the test item and the transformation product.
The limit of detection was 4.3% (Speyer 2.2), 3.7% (Speyer 2.3), 4.1% (Speyer 6S), 2.5% (Tilburg) and 2.0% (Aa & Maas) of applied radioactivity. The limit of quantification was 6.7% (Speyer 2.2), 7.7% (Speyer 2.3), 6.2% (Speyer 6S), 5.5% (Tilburg) and 2.7% (Aa & Maas) of applied radioactivity.

Confirmation of Identity of 14C-Labeled Test Item
The identity of 14C-labeled test item could be confirmed by comparison of retention time with the unlabeled test item.

Moisture Content
The moisture content of the soils was 1.9% (Speyer 2.2, preliminary test), 1.78% (Speyer 2.2 kinetics), 0.92 % (Speyer 2.3) and 3.0% (Speyer 6S, preliminary test), 6.88% (Speyer 6S, kinetics). The moisture content of the sludges was 2.85% (Tilburg, preliminary test), 1.97% (Tilburg, kinetics and isotherms) and 2.07% (Aa & Maas).

Solubility test
Solubility was tested to be <0.5 mg/L. For that reason, it was decided to use a maximum concentration of 0.1 mg/L during main study part.

Preliminary Test
The radiochemical purity of the test item in the stock solution was 91.8% at the start of the test.

Stability of Test Item / Adsorption to Container Material
This experiment was performed to test the adsorption of test item to container walls and its stability in 0.01 M CaCl2 solution with 210342/A Batch 10532JLM009-8.
The amount of radioactivity recovered in the solutions after 48 hours of contact time with the container material in the absence of soil/sludge was between 70% and 74% of the nominal applied activity in polypropylene vials and between 76% and 85% in glass containers.
Based on analysis by LC, 61.1-66.5% test item was recovered in the test solution in glass vials and 48.4-52.7% test item in polypropylene containers after 48 hours of contact time. 77.4-94.1% test item was recovered in the test solution in glass vials which were rinsed with unlabeled test item. The recovery of radioactivity in glass was better than the recovery in polypropylene containers. There was no significant difference between glass vials rinsed with or without unlabeled test item. The test item was not stable in CaCl2, therefore, a mass balance was determined after each sampling point in the kinetics and isotherms. A new batch of test item (210342/B batch 11800VXL001-2) was used for the kinetics and isotherms.
Further tests were performed in glass vials.

Determination of an Appropriate Test System:Solution Ratio
This experiment was performed with 210342/A Batch 10532JLM009-8.
The initial concentration in the solutions was approximately 0.05 mg/L.
Based on analysis by LC of the soil and sludge extracts, no test item was recovered in any of the test solutions or extracts after 24 hours of contact time. Based on these results the test item was shown to be unstable when in contact with soil/sludge. Since the transformation product is known this can also be followed using LC analysis during testing.
Based on the results of the ratio testing and an required adsorption level > 20% (preferably > 50%), a soil:solution ratio of 1:200 and a sludge:solution ratio of 1:1000 were selected for the kinetics experiment.

Determination of Equilibrium Time (Adsorption and Desorption Kinetics)
The radiochemical purity of the test item in the spike solution was 98.0% on the day of spiking.
The graphs show that for all soils, adsorption no equilibrium was reached. The amount of test item adsorbed to soil after 48 hours of contact time was 88.7% (Speyer 2.2), 93.8% (Speyer 2.3) and 93.7% (Speyer 6S). For both sludges, adsorption equilibrium was reached after approximately 24 hours. The amount of test item adsorbed to sludge after 48 hours of contact time was 77.5% (Tilburg) and 81.4% (Aa & Maas).
The graphs show that for soil no equilibrium was reached.
Desorption equilibrium for all soils and both sludges was reached after approximately 24 hours.
Based on the results of this experiment, it was decided to take samples after 24 hours of adsorption and after 24 hours desorption in the sludge isotherms experiment.
At the end of the adsorption and desorption phases, the supernatants were analyzed by LC.
Test item was observed during LC analysis to degrade into the known transformation product 2,5-di-tert-amylbenzoquinone which is also observed to be volatile in contact with soil. In some cases, no test item was detected, only transformation product. In sludge also degradation of the test item is observed, however sludge is shown to retain the volatile transformation product and for that reason Isotherms can be performed using sludge. For a qualitative follow up it was advised to also perform LC analysis of Isotherm samples.
The pH of the remaining supernatants ranged from 6.17 to 6.97 after adsorption and from 6.40 to 7.35 after desorption.
Mass balances were determined for one sample of each test system after each sampling time in the adsorption and desorption stage of the kinetics experiment. The mass balance of Tilburg sludge test system was just outside the acceptable range of 90-110% at 24 hours in the desorption phase (in total this is 72 hours in the system). The mass balance of Aa & Maas sludge test system was in the acceptable range of 90-100% at 24 hours in the desorption phase, indicating that no activity was lost during the timeframe of the experiment. The mass balances of soils were not in the range of 90-110%, due to the volatility of the transformation product in contact with soil.
Therefore, extraction of the sludge followed by LC analysis was also done for the sludges during the isotherm experiment.

Determination of Adsorption/Desorption Isotherms
The radiochemical purity of the test item in the spike solutions was 100% on the day of spiking the slurries.
At the end of the adsorption and desorption stage of the isotherm measurements, the pH of the supernatant was measured for each test system at the lowest and highest test item concentration. The pH ranged from 6.03 to 6.32 after adsorption and from 6.21 to 6.60 after desorption.
The mass balance of the sludge test systems was within the acceptable range of 90-110% at 24 hours in the adsorption and desorption phase. This indicates that no activity was lost during the timeframe of the experiment.
LC analysis of the samples showed that in sludge the transformation product at the end of the isotherm period was most abundant.

Recoveries of Concentration Steps in Soil and Sludge (% of Applied)

Test system	Acetonitrile extracts [% of applied]	Concentration [% of applied]	Procedural recovery concentration [%]
Speyer 2.2 Speyer 2.3 Speyer 6S Tilburg Aa & Maas	97.7 96.5 100.1 98.7 98.1	94.9 90.6 93.6 98.1 97.9	97.2 93.9 93.5 99.4 99.8

 

Adsorption to Container Material

Container material	Replicate	Recovery of radioactivity [% of nominal]
		t=0	t=3h	t=6h	t=24h	t=48h
Polypropylene	A B	100 100	92 88	88 87	80 84	74 70
Glass	A B	100 100	96 97	94 94	88 90	76 85
Glass^1	A B	100 100	n.d. n.d.	n.d. n.d.	87 88	82 82

n.d. Not determined

¹Glass containers rinsed with unlabeled test item

 

Adsorption in preliminary Test

Test system	Contact time [h]	Test system: solution ratio	Adsorption [%]
Speyer 2.2 soil	24 24 24 24 24	1:2 1:10 1:50 1:100 1:200	98.4 96.4 97.2 69.3 64.6
Speyer 6S soil	24 24 24 24 24	1:2 1:10 1:50 1:100 1:200	99.2 98.9 98.5 82.0 80.4
Tilburg sludge	24 24 24	1:100 1:500 1:1000	96.5 88.2 82.2

 

Mass Balances after Adsorption-Desorption Kinetics Experiment

Test system	Recovery after adsorption phase [% of applied]				Recovery after desorption phase [% of applied]
	3 hours	6 hours	24 hours	48 hours	3 hours	6 hours	24 hours	48 hours
Speyer 2.2 Speyer 2.3 Speyer 6S Tilburg Aa & Maas	87 84 81 96 97	82 72 73 93 96	57 43 47 92 95	37 25 28 90 96	36 23 28 93 94	34 24 24 91 95	32 21 22 89 91	32 23 24 84 84

 

Freundlich Adsorption Isotherm Parameters

Test system	KF^ads [mL/g]	KF,oc^ads [mL/g]	l/n	r^2	Data points
Tilburg sludge Aa & Maas sludge	2791.43 3716.98	8308 10441	0.9156 0.9367	0.9875 0.9978	15 15

 

Freundlich Desorption Isotherm Parameters

Test system	KF^ads [mL/g]	KF,oc^ads [mL/g]	l/n	r^2	Data points
Tilburg sludge Aa & Maas sludge	3757.54 4829.39	11183 13566	0.9241 0.9450	0.9982 0.9990	10 10

 

Mass Balances after Adsorption-Desorption Isotherms Experiment

Test system	Code	Recovery after adsorption phase [% of applied]	Recovery after desorption phase [% of applied]
Tilburg         Aa & Maas	A1 B1 C1 D1 E1 A1 B1 C1 D1 E1	98 97 99 100 101 97 97 94 99 98	93 84^1 92 95 97 -^2 97 96 97 99

¹Low mass balance due to unexpected low activity in subsample.

²Sample was lost in during processing.

 

Detailed Results Adsorption Kinetics

Test system	Replicate	Moisture [%]	Weighed test system [g]	Dry mass of soil msoil [g]	Water volume in weighed test system [g]	Spike volume^1 [mL]	m0 [µg]	0.01 M CaCl2added [g]	V0 [mL]	C0 [µg/mL]
Speyer 2.2	E1 E2 E3 E4 F1 F2 F3 F4 B1	1.78 1.78 1.78 1.78 1.78 1.78 1.78 1.78 1.78	0.2253 0.2228 0.2247 0.2239 0.2274 0.2249 0.2223 0.2252 0.2237	0.2213 0.2188 0.2207 0.2199 0.2234 0.2209 0.2183 0.2212 0.2197	0.0040 0.0040 0.0040 0.0040 0.0040 0.0040 0.0040 0.0040 0.0040	0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387	0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.00	44.9963 45.0149 45.0148 45.0009 44.9986 45.0138 45.0342 45.0110 45.0024	45.04 45.06 45.06 45.04 45.04 45.06 45.08 45.05 45.05	0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.00
Speyer 2.3	E1 E2 E3 E4 F1 F2 F3 F4 B1	0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92 0.92	0.2263 0.2228 0.2250 0.2293 0.2250 0.2269 0.2270 0.2278 0.2261	0.2242 0.2208 0.2229 0.2272 0.2229 0.2248 0.2249 0.2257 0.2240	0.0021 0.0020 0.0021 0.0021 0.0021 0.0021 0.0021 0.0021 0.0021	0.0387 0.0.387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387	0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.00	45.0089 45.0499 45.0235 45.0497 45.0432 45.0043 44.9977 45.0051 45.0088	45.05 45.09 45.06 45.09 45.08 45.05 45.04 45.05 45.05	0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.00
Speyer 6S	E1 E2 E3 E4 F1 F2 F3 F4 B1	6.88 6.88 6.88 6.88 6.88 6.88 6.88 6.88 6.88	0.2278 0.2243 0.2288 0.2261 0.2261 0.2271 0.2262 0.2243 0.2230	0.2121 0.2089 0.2130 0.2105 0.2105 0.2115 0.2106 0.2089 0.2076	0.0157 0.0154 0.0158 0.0156 0.0156 0.0156 0.0156 0.0154 0.0154	0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387	0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.00	44.9898 45.0110 45.0026 44.9943 44.9989 45.0234 45.0247 45.0235 45.0182	45.04 45.07 45.06 45.05 45.05 45.08 45.08 45.08 45.07	0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.00
Tilburg	E1 E2 E3 E4 F1 F2 F3 F4 B1	1.97 1.97 1.97 1.97 1.97 1.97 1.97 1.97 1.97	0.0456 0.0453 0.0452 0.0452 0.0454 0.0454 0.0450 0.0455 0.0452	0.0447 0.0444 0.0443 0.0443 0.0445 0.0445 0.0441 0.0446 0.0443	0.0009 0.0009 0.0009 0.0009 0.0009 0.0009 0.0009 0.0009 0.0009	0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387	0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.00	45.0044 45.0097 45.0108 44.9979 44.9921 45.0110 44.9897 44.9990 44.9972	45.04 45.05 45.05 45.04 45.03 45.05 45.03 45.04 45.04	0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.00
Aa & Maas	E1 E2 E3 E4 F1 F2 F3 F4 B1	2.07 2.07 2.07 2.07 2.07 2.07 2.07 2.07 2.07	0.0455 0.0457 0.0453 0.0458 0.0458 0.0452 0.0460 0.0456 0.0459	0.0446 0.0448 0.0444 0.0449 0.0449 0.0443 0.0450 0.0447 0.0449	0.0009 0.0009 0.0009 0.0009 0.0009 0.0009 0.0010 0.0009 0.0010	0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387 0.0387	0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.91 0.00	45.0044 45.0113 45.0198 45.0045 45.0072 45.0149 44.9944 44.9869 44.9937	45.04 45.05 45.06 45.04 45.05 45.05 45.03 45.03 45.03	0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.00

1 To the blanks, acetonitrile was spiked instead of spike solution

 

Detailed Results Adsorption Kinetics (continued)

Test system	Replicate	Activity in Va^A [dpm]				mmads [µg]
		t1	t2	t3	t4	t1	t2	t3	t4
Speyer 2.2	E1 E2 E3 E4 F1 F2 F3 F4 B1	3404               25	22550             28	1270           29	748 726 677 736 692 27	0.0120	0.0089	0.0044	0.0026 0.0025 0.0023 0.0025 0.0024
Speyer 2.3	E1 E2 E3 E4 F1 F2 F3 F4 B1	3724               24	2774             27	1089           26	419 373 410 406 410 25	0.0131	0.0097	0.0038	0.0014 0.0012 0.0014 0.0014 0.0014
Speyer 6S	E1 E2 E3 E4 F1 F2 F3 F4 B1	2990               27	2181             24	1067           37	395 459 419 342 425 26	0.0105	0.0076	0.0037	0.0013 0.0015 0.0014 0.0011 0.0014
Tilburg	E1 E2 E3 E4 F1 F2 F3 F4 B1	1869               24	1599             29	1224           25	1407 1397 1341 1437 1373 22	0.0065	0.0056	0.0043	0.0049 0.0049 0.0047 0.0050 0.0048
Aa & Maas	E1 E2 E3 E4 F1 F2 F3 F4 B1	1319               27	1158             24	1047           24	1213 1101 1129 1182 1157 25	0.0046	0.0040	0.0036	0.0042 0.0038 0.0039 0.0041 0.0041

t₁: 3h, t₂: 6h, t₃: 24h, t₄: 48h

 

Detailed Results Adsorption Kinetics (continued)

Test system	Replicate	maq^ads [µg]				ms^ads [µg]				Ati [%]
		t1	t2	t3	t4	∆t1	∆t2	∆t3	∆t4	t1	t2	t3	t4
Speyer 2.2	E1 E2 E3 E4 F1 F2 F3 F4	0.5397	0.3940	0.1895	0.1075 0.1042 0.0969 0.1058 0.0992	0.3669	0.1457	0.2045	0.0820 0.0853 0.0925 0.0837 0.0903	40.5	56.5	79.1	88.1 88.5 89.3 88.3 89.1
Speyer 2.3	E1 E2 E3 E4 F1 F2 F3 F4	0.5911	0.4295	0.1623	0.0588 0.0519 0.0574 0.0568 0.0574	0.3155	0.1616	0.2672	0.1035 0.1104 0.1049 0.1055 0.1049	34.8	52.6	82.1	93.5 94.3 93.7 93.7 93.7
Speyer 6S	E1 E2 E3 E4 F1 F2 F3 F4	0.4733	0.3371	0.1573	0.0550 0.0646 0.0586 0.0472 0.0595	0.4333	0.1362	0.1798	0.1022 0.0927 0.0986 0.1101 0.0977	47.8	62.8	82.7	93.9 92.9 93.5 94.8 93.4
Tilburg	E1 E2 E3 E4 F1 F2 F3 F4	0.2947	0.2452	0.1830	0.2065 0.2049 0.1967 0.2109 0.2014	0.6119	0.0495	0.0622	-0.0234 -0.0219 -0.0136 -0.0279 -0.0184	67.5	73.0	79.8	77.2 77.4 78.3 76.7 77.8
Aa & Maas	E1 E2 E3 E4 F1 F2 F3 F4	0.2064	0.1771	0.1562	0.1771 0.1604 0.1646 0.1725 0.1687	0.7002	0.0292	0.0209	-0.0209 -0.0042 -0.0084 -0.0163 -0.0125	77.2	80.5	82.8	80.5 82.3 81.8 81.0 81.4

t₁: 3h, t₂: 6h, t₃: 24h, t₄: 48h

 

Detailed Results Adsorption Kinetics (continued)

Test system	Replicate	ms^ads(eq) [µg]	maq^ads(aq) [µg]	Kd [mL/g]	% om	Kom [mL/g]	% oc	Koc pmL/g]
Speyer 2.2 Speyer 2.3 Speyer 6S Tilburg Aa & Maas	E1-4 E1-4 E1-4 E1-4 E1-4	0.7991 0.8478 0.8516 0.7002 0.7295	0.1075 0.0588 0.550 0.2065 0.1771	1521.0 2903.8 3302.7 3438.1 4157.2	2.79 1.12 3.1 57.9 61.4	54798.2 259128.6 107624.4 5935.3 6773.5	1.61 0.65 1.78 33.6 35.6	94472.0 446737.7 185544.4 10232.4 11677.5

t₁: 3h, t₂: 6h, t₃: 24h, t₄: 48h

 

Detailed Results Desorption Kinetics

Test system	Replicate	VR [mL]	Vadd [mL]	VT [mL]	Activity in Va^D [dpm]
					t1	t2	t3	t4
Speyer 2.2	F1 F2 F3 F4 B12	44.6377 44.6907 44.6210 44.5917 44.6657	44.6381 44.6309 44.6254 44.5917 44.6594	45.0417 44.9967 45.0813 45.0537 41.0388	228       27	228     26	201   24	194 25
Speyer 2.3	F1 F2 F3 F4 B12	44.7273 44.7442 44.6598 44.7135 41.7821	44.7376 44.7482 44.6576 44.7294 41.7831	45.0943 45.0491 45.0363 5.0618 41.0506	89       40	107     24	116   23	125 24
Speyer 6S	F1 F2 F3 F4 B12	44.5600 44.6510 44.6150 44.4635 41.6791	44.5645 44.6578 44.6150 44.4623 41.7023	45.0577 45.0845 45.0790 45.0764 41.0955	155       31	148     26	139   25	130 27
Tilburg	F1 F2 F3 F4 B12	44.4098 44.3958 44.5575 44.4390 41.5355	44.4142 44.4675 44.5518 44.4459 41.5356	45.0361 45.1223 45.0236 45.0455 41.0369	520       23	448     24	246   37	268 33
Aa & Maas	F1 F2 F3 F4 B12	44.1605 44.1371 44.1400 44.3077 41.3537	44.1624 44.1409 44.1431 44.3033 41.3523	45.0487 45.0583 45.0372 45.0221 41.0320	605       23	456     27	279   25^1	243 25^1

t₁: 3h, t₂: 6h, t₃: 24h, t₄: 48h

1 Very high activity was measured (330 and 656), therefore the mean blank of t=3h and t=6h was used for calculations

 

Detailed Results Desorption Kinetics (continued)

Test system	Replicate	mm^des(ti) [µg]				maq^ads(eq) [µg]	maq^A [µg]	maq^des(∆ti) [µg]
		t1	t2	t3	t4			t1	t2	t3	t4
Speyer 2.2	F1 F2 F3 F4	0.0007	0.0007	0.0006	0.0006	0.1075 0.1075 0.1075 0.1075	0.0090 0.0081 0.0101 0.0103	0.0231	0.0241	0.0182	0.0167
Speyer 2.3	F1 F2 F3 F4	0.0002	0.0003	0.0003	0.0004	0.0588 0.0588 0.0588 0.0588	0.0079 0.0067 0.084 0.074	-0.0001	0.0066	0.0064	0.0088
SPEYER 6s	F1 F2 F3 F4	0.0004	0.0004	0.0004	0.0004	0.0550 0.0550 0.0550 0.0550	0.0110 0.0095 0.0103 0.0136	0.0089	0.0100	0.0079	0.0028
Tilburg	F1 F2 F3 F4	0.0018	0.0015	0.0007	0.0008	0.2065 0.2065 0.2065 0.2065	0.0139 0.0146 0.0105 0.0134	0.0655	0.0532	0.0228	0.0242
Aa & Maas	F1 F2 F3 F4	0.0021	0.0015	0.0009	0.0008	0.1771 0.1771 0.1771 0.1771	0.0198 0.0204 0.0199 0.0160	0.0732	0.0481	0.0206	0.0188

t₁: 3h, t₂: 6h, t₃: 24h, t₄: 48h

 

Detailed Results Desorption Kinetics (continued)

Test system	Replicate	ms^ads(eq) [µg]	Dti [%]				maq^des(eq) [µg]	msoil [g]	Kdes [mL/g]
			t1	t2	t3	t4
Speyer 2.2	F1 F2 F3 F4	0.7991 0.7991 0.7991 0.7991	2.9	3.0	2.3	2.1	0.0821 0.0821 0.0821 0.0821	0.2234 0.2209 0.2183 0.2212	1761 1779 1803 1779
Speyer 2.3	F1 F2 F3 F4	0.8478 0.8478 0.8478 0.8478	0.0	0.8	0.8	1.0	0.0217 0.0217 0.0217 0.0217	0.2229 0.2248 0.2249 0.2257	7712 7639 7634 7611
Speyer 6S	F1 F2 F3 F4	0.8516 0.8516 0.8516 0.8516	1.0	1.2	0.9	0.3	0.0296 0.0296 0.0296 0.0296	0.2105 0.2115 0.2106 0.2089	5942 5919 5942 5992
Tilbury	F1 F2 F3 F4	0.7002 0.7002 0.7002 0.7002	9.4	7.6	3.3	3.5	0.1657 0.1657 0.1657 0.1657	0.0445 0.0445 0.0441 0.0446	3263 3269 3291 3256
Aa & Maas	F1 F2 F3 F4	0.7295 0.7295 0.7295 0.7295	10.0	6.6	2.8	2.6	0.1607 0.1607 0.1607 0.1607	0.0449 0.0443 0.0450 0.0447	3554 3602 3538 3568

t₁: 3h, t₂: 6h, t₃: 24h, t₄: 48h

 

Mass Balances Adsorption and Desorption Kinetics

Test system	Sampling point [hours]	Volume decanted after desorption [mL]	Activity decanted after desorption [dpm]	Volume decanted after adsorption [mL]	Activity decanted after adsorption [dpm]	Activity adsorbed to test system (extraction) [dpm]	Activity adsorbed to test system (combustion) [dpm]	Activity applied [dpm]	Mass balance [%]
Speyer 2.2	3 ads 6 ads 24 ads 48 ads			44.6741 44.5837 44.4661 44.6600	150954 112440 55182 32200	71203 95131 88852 60290	1199 1012 2108 1584	255666 255666 255666 255666	87 82 57 37
	3 des 6 des 24 des 48 des	44.6379 44.6384 44.6596 44.6785	8972 9017 7905 7551			50229 47133 41178 42304	1204 1041 1222 1130	255666 255666 255666 255666	36 34 32 32
Speyer 2.3	3 ads 6 ads 24 ads 48 ads			44.6391 44.7781 44.4170 44.4530	165165 123005 47215 17514	47628 60605 61601 44494	1394 1711 1596 1092	255666 255666 255666 255666	84 72 43 25
	3 des 6 des 24 des 48 des	44.7645 44.6887 44.4648 44.6909	2193 3709 4135 4514			41379 40251 32296 35926	855 864 738 891	255666 255666 255666 255666	23 24 21 23
Speyer 6S	3 ads 6 ads 24 ads 48 ads			44.4644 44.5198 44.0487 44.3539	131748 96029 45370 16367	73003 88900 72882 53738	2155 2058 2336 1862	255666 255666 255666 255666	81 73 47 28
	3 des 6 des 24 des 48 des	44.5807 44.5957 44.5632 44.6143	5528 5441 5080 4595			44039 37547 34462 36771	1869 463 1757 2197	255666 255666 255666 255666	28 24 22 24
Tilburg	3 ads 6 ads 24 ads 48 ads			44.4969 44.4191 44.2006 44.4167	82097 69738 52997 61517	161553 166041 180016 166737	1214 1312 1833 2235	255666 255666 255666 255666	96 93 92 90
	3 des 6 des 24 des 48 des	44.4547 44.5058 44.4681 44.4346	22094 18870 9294 10442			153179 154000 153833 141385	1686 1589 2211 1849	255666 255666 255666 255666	93 91 89 84
Aa & Maas	3 ads 6 ads 24 ads 48 ads			44.2113 44.0561 44.1047 44.2461	57121 49960 45119 52564	190951 194922 194899 191918	934 1499 1593 1572	255666 255666 255666 255666	97 96 95 96
	3 des 6 des 24 des 48 des	44.0933 44.4726 44.1135 44.1751	25662 19079 11205 9630			164782 172288 169415 151928	1139 2122 2034 2219	255666 255666 255666 255666	94 95 91 84

ads adsorption phase

des desorption phase

 

pH of Supernatants after the Adsorption and Desorption Kinetics

Test system	pH of supernatant after adsorption	pH of supernatant after desorption
Speyer 2.2 soil Speyer 2.3 soil Speyer 6S soil Tilburg sludge Aa & Maas sludge Control A	6.80 6.76 6.97 6.64 6.17 6.54	6.58 6.63 7.35 6.52 6.40 6.65

 

Detailed Results Adsorption Isotherms

Test system	Replicate	Weighed test system [g]	Dry mass of test system [g]	Water volume In test system [mL]	0.01 M CaCl2added [mL]	Spike solution added^1 [mL]	V0 [mL]	Va^A [mL]	Activity in Va^A [dpm]	mm^ads(eq) [µg]	C0 [µg/mL]	Caq^ads(eq) [µg/mL]	Csads(eq) [µg/mL]	Adsorption
Tilburg	A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3 E1 E2 E3 B1	0.0460 0.0503 0.0478 0.0458 0.0473 0.0440 0.0455 0.0479 0.0445 0.0463 0.0454 0.0453 0.0494 0.0467 0.0458 0.0434	0.05 0.05 0.05 0.04 0.05 0.04 0.04 0.05 0.04 0.05 0.04 0.04 0.05 0.05 0.04 0.04	0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001	45.1532 45.0134 45.2622 45.2480 45.0792 45.0291 45.0440 45.0406 45.0505 45.0217 45.0088 45.0202 45.0209 45.0474 45.0495 45.0684	0.0302 0.0302 0.0302 0.1206 0.1206 0.1206 0.0322 0.0322 0.0322 0.0643 0.0643 0.0643 0.1608 0.1608 0.1608 0.1608	45.2 45.0 45.3 45.4 45.2 45.2 45.1 45.1 45.1 45.1 45.1 45.1 45.2 45.2 45.2 45.2	10 10 10 10 10 10 1 1 1 1 1 1 1 1 1 1	426 482 467 2026 1052 2059 1044 1026 975 1898 2161 2405 6151 5874 6070 30	0.0014 0.0016 0.0016 0.0071 0.0036 0.0072 0.0036 0.0035 0.0034 0.0066 0.0076 0.0084 0.0217 0.0207 0.214	0.0010 0.0010 0.0010 0.0040 0.0040 0.0040 0.0192 0.0192 0.0192 0.0409 0.0409 0.0409 0.1009 0.1008 0.1008	0.0001 0.0002 0.0002 0.0007 0.0004 0.0007 0.0036 0.0035 0.0034 0.0066 0.0076 0.0084 0.0217 0.0207 0.0214	0.8213 0.7333 0.7759 3.3098 3.5443 3.4365 15.7339 15.0071 16.3399 34.0292 33.7607 32.9544 73.8641 79.0924 79.9454	85.4 83.3 83.8 82.2 90.9 82.0 81.2 81.6 82.5 83.8 81.5 79.4 78.5 79.4 78.7
Aa & Maas	A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3 E1 E2 E3 B1	0.0440 0.0442 0.0462 0.0449 0.0473 0.0460 0.0468 0.0462 0.0450 0.0477 0.0488 0.0461 0.0446 0.0453 0.0482 0.0455	0.04 0.04 0.05 0.04 0.05 0.05 0.05 0.05 0.04 0.05 0.05 0.05 0.04 0.04 0.05 0.04	0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001	45.0374 45.0651 45.2071 45.0039 45.0863 45.0114 45.0473 45.1192 45.0231 45.0166 45.0306 45.0465 45.0550 45.0041 45.0345 45.0181	0.0302 0.0302 0.0302 0.1206 0.1206 0.1206 0.0322 0.0322 0.0322 0.0643 0.0643 0.0643 0.1608 0.1608 0.1608 0.1608	45.1 45.1 45.2 45.1 45.2 45.1 45.1 45.2 45.1 45.1 45.1 45.1 45.2 45.2 45.2 45.2	10 10 10 10 10 10 1 1 1 1 1 1 1 1 1 1	394 400 370 1956 1824 1685 781 861 806 1799 1843 1942 5153 5161 4781 33	0.0013 0.0013 0.0012 0.0068 0.0064 0.0059 0.0027 0.0029 0.0027 0.0063 0.0064 0.0068 0.0182 0.0182 0.0168	0.0010 0.0010 0.0010 0.0040 0.0040 0.0040 0.0192 0.0191 0.0192 0.0409 0.0409 0.0409 0.1008 0.1009 0.1009	0.0001 0.0001 0.0001 0.0007 0.0006 0.0006 0.0027 0.0029 0.0027 0.0063 0.0064 0.0068 0.0182 0.0182 0.0168	0.8715 0.8653 0.8380 3.4049 3.2765 3.4195 16.2156 16.1392 16.7751 33.3630 32.4621 34.0106 85.4258 84.0977 80.3151	86.7 86.5 87.5 83.0 84.1 85.4 86.2 84.6 85.7 84.7 84.3 83.4 82.0 82.0 83.3
Control	A1 A2 B1 B2 C1 C2 D1 D2 E1 E2				45.0387 45.0359 45.0398 45.0580 45.0533 45.0438 45.1605 45.0478 45.0686 45.0209	0.0302 0.0302 0.1206 0.1206 0.0322 0.0322 0.0643 0.0643 0.1608 0.1608	45.1 45.1 45.2 45.2 45.1 45.1 45.2 45.1 45.2 45.2	10 10 10 10 1 1 1 1 1 1	2553 2547 10377 10418 5294 5213 10796 14357 32373 27566	0.0090 0.0089 0.0367 0.0369 0.0187 0.0184 0.0382 0.0508 0.1148 0.0977	0.0010 0.0010 0.0040 0.0040 0.0192 0.0192 0.0408 0.0409 0.1008 0.1009	0.0009 0.0009 0.0037 0.0037 0.0187 0.0184 0.0382 0.0508 0.1148 0.0977		6.8 7.0 8.2 7.8 2.4 4.0 6.2 -24.4 -13.9 3.1

¹To the blanks, acetonitrile was spiked instead of spike solution

 

Detailed Results Desorption Isotherms

Test system	Replicate	Vremoved [mL]	Vadded [mL]	V0,corr [mL]	Vadded– Vremoved [mL]	Vr^F [mL]	Activity on Vr^F [dpm]	mm^des(eq) [µg]	maq^A [µg]	maq^des(eq) [µg]	Caq^des(eq) [µg/mL]	Cs^des(eq) [µg/g]
Tilburg	A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3 E1 E2 E3 B1	43.9828 44.2094 44.5305 44.5984 44.3741 44.3666 44.2309 44.1042 44.1406 44.2110 44.2960 44.2944 44.3977 44.2956 44.3994 44.2714	44.4519 44.5437   44.5030 44.3490   44.1932 44.2307   44.2896 44.3306   44.2932 44.4324 44.2846	45.2871     45.3296     45.1627     45.0676     45.2067   45.2433	0.2425     0.1289     0.0890     -0.0064     -0.0024   0.0132	10 10   10 10   1 1   1 1   1 1 1	322 364   1272 1518   742 804   1412 1620   4039 4507 67	0.0009 0.0011   0.0043 0.0051   0.0024 0.0026   0.0048 0.0055   0.0141 0.0158	0.0001 0.0001   0.0003 0.0006   0.0034 0.0032   0.0059 0.0067   0.0189 0.0174	0.0040 -0.0001   0.0191 -0.0006   0.1047 -0.0032   0.2092 -0.0067   0.6181 -0.0174	0.0001 0.0001   0.0004 0.0005   0.0024 0.0026   0.0048 0.0055   0.0141 0.0158	0.7 0.8   3.1 3.4   12.8 16.4   29.1 33.1   65.6 80.3
Aa & Mass	A1 A2 A3 B1 B2 B3 C1 C2 C3 D1 D2 D3 E1 E2 E3 B1	44.3012 44.2539 44.2529 44.0396 44.2535 44.1978 44.1721 44.1549 44.1077 43.9225 44.0871 44.0540 44.1539 44.1827 44.0408 44.1680	44.3652 44.5766   44.2547 44.1965   44.1597 44.1789   44.0910 44.1003   44.2603 44.3288 44.1771	45.2074     45.2090     45.1571     45.0997     45.2434   45.1889	01113     0.0012     0.0048     0.0039     0.0776   0.0091	10 10   10 10   1 1   1 1   1 1 1	327 357   1244 1341   600 758   1314 1506   3664 3616 59	0.0010 0.0011   0.0042 0.0045   0.0019 0.0025   0.0045 0.0051   0.0128 0.0126	0.0001 0.0001   0.0006 0.0005   0.0029 0.0026   0.0065 0.0072   0.0179 0.0195	0.0042 -0.0001   0.0184 -0.0005   0.0837 -0.0026   0.1943 -0.0072   0.5608 -0.0195	0.0001 0.0001   0.0004 0.0005   0.0019 0.0025   0.0045 0.0051   0.0128 0.0126	0.8 0.8   2.9 3.4   14.3 16.8   28.4 34.2   71.5 80.7
Control	A1 A2 B1 B2 C1 C2 D1 D2 E1 E2			45.0689 45.0661 45.1604 45.1786 45.0855 45.0760 45.2248 45.1121 45.2294 45.1817		10 10 10 10 1 1 1 1 1 1	2231 2414 9703 9955 5134 5017 6779 10424 18162 12497	0.0078 0.0085 0.0343 0.0352 0.0181 0.0177 0.0240 0.0369 0.0643 0.0442	0.0404 0.0403 0.1659 0.1666 0.8428 0.8297 1.7282 2.2938 5.1908 4.4148	-0.0051 -0.0021 -0.0108 -0.0074 -0.0256 -0.0313 -0.6445 -0.6295 -2.2804 -2.4155	0.0008 0.0008 0.0034 0.0035 0.0181 0.0177 0.0240 0.0369 0.0643 0.0442

 

pH of Supernatants after Adsorption and Desorption Isotherms

Test system (test item concentration)	pH of supernatant after adsorption	pH of supernatant after desorption
Tilburg (0.001 mg/L) Tilburg (0.1 mg/L)	6.06 6.03	6.29 6.42
Aa & Maas (0.001 mg/L) Aa & Maas (0.1 mg/L)	6.32 6.26	6.21 6.38
Control (0.001 mg/L) Control (0.1 mg/L)	6.17 6.14	6.60 6.55

 

Mass Balances Adsorption and Desorption Isotherms

Test system	Code	Volume decanted after desorption [mL]	Activity decanted after desorption [dpm]	Volume decanted after adsorption [mL]	Activity decanted after adsorption [dpm]	Activity adsorbed to test system (extraction) [dpm]	Activity adsorbed to test system (combustion) [dpm]	Activity applied [dpm]	Mass balance [%]
Tilburg	A1 ads B1 ads C1 ads D1 ads E1 ads			1742 8902 44850 82586 271758	12228 50941 243515 519561 1274781	9987 39482 189005 428622 1006953	63118 22793 6923 6423 18832	12228 50941 243515 519561 1284781	98 97 99 100 101
	A2 des B2 des C2 des D2 des E2 des	44.4438 44.5215 44.1368 44.3036 44.4034	1133 5365 29792 59588 176370	44.2094 44.3741 44.1042 44.2960 44.3977	1998 4535 43928 94395 259460	8076 32617 148901 334887 796144	131 410 1992 4049 10630	12228 50941 243515 519561 1284781	93 84 92 95 97
Aa & Maas	A1 ads B1 ads C1 ads D1 ads E1 ads			1599 8469 33041 77567 226068	12228 50941 243515 519561 1284781	9356 40585 193723 430837 1024479	912 560 2184 3765 12031	12228 505941 243515 519561 1284781	97 97 94 99 98
	A2 des^1 B2 des C2 des D2 des E2 des	44.3056 44.2555 44.2721 44.1767 44.2911	- 5244 23951 59418 159257	44.2539 44.2535 44.1549 44.0871 44.1827	- 7926 36560 79798 226569	35714 172044 538636 848960	- 723 2399 4316 11264	12228 50941 243515 519561 1274781	- 97 96 97 99

ads adsorption phase

des desorption phase

¹sample was lost in during processing

Validity criteria fulfilled:

yes

Conclusions:

In conclusion, adsorption and desorption isotherms of the test item could be described by the Freundlich equation for clay. No adsorption equilibrium was reached for all soils do to the continuous transfer of test item into a more volatile transformation product not retained in the soil.

Executive summary:

The objective of this study was to obtain information on the adsorption/desorption behavior of C14-Lowinox® AH 25 on soil and sludge. Adsorption and desorption parameters were determined using the batch equilibrium method with three soils and two sludges.

The adsorption and desorption behavior of the test item was studied on Speyer 2.2, Speyer 2.3 and Speyer 6S soil and Tilburg and Aa & Maas sludges. The experiments were carried out at 20 ± 2°C in the dark on a roller mixer.

Initially an analytical method was developed for the extraction and analysis of C14-Lowinox® AH 25 in soil and sludge. The performance check of the analytical method for the analysis of 14C-labeled test item in soil and sludge was successfully performed.

The limit of detection was 4.3% (Speyer 2.2), 3.7% (Speyer 2.3), 4.1% (Speyer 6S), 2.5% (Tilburg) and 2.0% (Aa & Maas) of applied radioactivity.

The limit of quantification was 6.7% (Speyer 2.2), 7.7% (Speyer 2.3), 6.2% (Speyer 6S), 5.5% (Tilburg) and 2.7% (Aa & Maas) of applied radioactivity.

Limit of detection and limit of quantification were both determined on the parent compound.

Since the test item is known to form transformation products directly after being in contact with solution this influences calculated results. For the current study results as calculated are sufficient and accepted.

Adsorption and desorption kinetics were determined at an initial test item concentration of approximately 0.02 mg/L. No adsorption equilibrium was reached for all soils do to the continuous transfer of test item into a more volatile transformation product not retained in the soil. For both sludges an adsorption equilibrium was reached after 24 hours contact time.

Desorption equilibrium was reached after 24 hours contact time in the presence of both soil and sludge. The test item was shown to be unstable during the time frame of the experiment for all soils and sludges.

Adsorption and desorption isotherms were determined over a concentration range from approximately 0.001 to 0.1 mg/L at a sludge:0.01 M CaCl2 solution ratio of 1:1000. The adsorption and desorption isotherms of the test item could be described by the Freundlich equation. Freundlich adsorption and desorption coefficients are summarized in the table below.

 

Freundlich Adsorption and Desorption Coefficients

Test system	Texture [USDA]	Organic carbon [%]	KF^ads [mL/g]	KF,oc^ads [mL/g]	l/n	KF,oc^des [mL/g]
Tilburg Aa & Maas	Clay Clay	33.6 35.6	2791.43 3716.98	8308 10441	0.9156 0.9367	11183 13566

 

Description of key information

OECD 121

The Koc and log Koc value of the test substance was:

Test substance	Neutral pH
	Koc	Log Koc
	4.8 x 10^3	3.68

OECD 106

Freundlich Adsorption and Desorption Coefficients were determined as follows

Test system	Texture [USDA]	Organic carbon [%]	KF^ads [mL/g]	KF,oc^ads [mL/g]	KF,oc^des [mL/g]
Tilburg	Clay	33.6	2791.43	8308	11183
Aa & Maas	Clay	35.6	3716.98	10441	13566

Key value for chemical safety assessment

Koc at 20 °C:

4 800

Additional information

The HPLC method using soil-adsorption-reference data was chosen for the determination of the adsorption coefficient of Lowinox® AH25.

 

The Koc and log Koc value of the test substance was:

Test substance	Neutral pH
	Koc	Log Koc
	4.8 x 10^3	3.68

 

No impurities with a peak area percentage of > 1% of the total peak area were observed.

An OECD 106 study was also conducted on the substance. The objective of this study was to obtain information on the adsorption/desorption behaviour of C14-Lowinox® AH 25 on soil and sludge. Adsorption and desorption parameters were determined using the batch equilibrium method with three soils and two sludges.

The adsorption and desorption behavior of the test item was studied on Speyer 2.2, Speyer 2.3 and Speyer 6S soil and Tilburg and Aa & Maas sludges. The experiments were carried out at 20 ± 2°C in the dark on a roller mixer.

Initially an analytical method was developed for the extraction and analysis of C14-Lowinox® AH 25 in soil and sludge. The performance check of the analytical method for the analysis of 14C-labeled test item in soil and sludge was successfully performed.

The limit of detection was 4.3% (Speyer 2.2), 3.7% (Speyer 2.3), 4.1% (Speyer 6S), 2.5% (Tilburg) and 2.0% (Aa & Maas) of applied radioactivity.

The limit of quantification was 6.7% (Speyer 2.2), 7.7% (Speyer 2.3), 6.2% (Speyer 6S), 5.5% (Tilburg) and 2.7% (Aa & Maas) of applied radioactivity.

Limit of detection and limit of quantification were both determined on the parent compound.

Since the test item is known to form transformation products directly after being in contact with solution this influences calculated results. For the current study results as calculated are sufficient and accepted.

Adsorption and desorption kinetics were determined at an initial test item concentration of approximately 0.02 mg/L. No adsorption equilibrium was reached for all soils do to the continuous transfer of test item into a more volatile transformation product not retained in the soil. For both sludges an adsorption equilibrium was reached after 24 hours contact time.

Desorption equilibrium was reached after 24 hours contact time in the presence of both soil and sludge. The test item was shown to be unstable during the time frame of the experiment for all soils and sludges.

Adsorption and desorption isotherms were determined over a concentration range from approximately 0.001 to 0.1 mg/L at a sludge:0.01 M CaCl2 solution ratio of 1:1000. The adsorption and desorption isotherms of the test item could be described by the Freundlich equation. Freundlich adsorption and desorption coefficients are summarized in the table below.

Freundlich Adsorption and Desorption Coefficients were determined as follows

Test system	Texture [USDA]	Organic carbon [%]	KF^ads [mL/g]	KF,oc^ads [mL/g]	KF,oc^des [mL/g]
Tilburg	Clay	33.6	2791.43	8308	11183
Aa & Maas	Clay	35.6	3716.98	10441	13566