Registration Dossier
Registration Dossier
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EC number: 217-588-1 | CAS number: 1897-45-6
Adsorption / desorption
Administrative data
Link to relevant study record(s)
- Endpoint:
- adsorption / desorption: screening
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- study well documented, meets generally accepted scientific principles, acceptable for assessment
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- 14C-labelled test substance is applied to soils in sealed glass tubes with screw caps. The adsorption equilibration is lasted for 24-h at 25 °C and followed by a 24-h desorption test. The adsorption and desorption coefficient are calculated based on the test substance concentration in soils.
- GLP compliance:
- no
- Type of method:
- batch equilibrium method
- Media:
- soil
- Radiolabelling:
- yes
- Test temperature:
- 25 °C
- Analytical monitoring:
- yes
- Details on sampling:
- DETERMINATION OF EQUILIBRATION TIME FOR 14C-LABELLED TEST SUBSTANCE
- Sampling intervals: 1, 3, 5, 8 and 24 hours
ADSORPTION OF THE TEST SUBSTANCE AND DDT
- Sampling intervals: After equilibration, the samples were removed from the bath, centrifuged , and the radioactivity in the supernatant Quantitated by liquid scintillation counting.
DESORPTION OF THE TEST SUBSTANCE AND DDT
- Sampling intervals: After equilibration, the samples were removed from the bath, centrifuged , and the radioactivity in the supernatant Quantitated by liquid scintillation counting. This desorption phase was carried out twice. - Matrix no.:
- #1
- Matrix type:
- sand
- % Clay:
- 4
- % Silt:
- 0
- % Sand:
- 96
- % Org. carbon:
- 0.35
- pH:
- 6.4
- CEC:
- 1.8 meq/100 g soil d.w.
- Matrix no.:
- #2
- Matrix type:
- sandy loam
- % Clay:
- 4
- % Silt:
- 30.4
- % Sand:
- 65.6
- % Org. carbon:
- 1.86
- pH:
- 5.7
- CEC:
- 12.64 meq/100 g soil d.w.
- Matrix no.:
- #3
- Matrix type:
- Silt
- % Clay:
- 8
- % Silt:
- 82
- % Sand:
- 10
- % Org. carbon:
- 0.41
- pH:
- 7.5
- CEC:
- 10 meq/100 g soil d.w.
- Matrix no.:
- #4
- Matrix type:
- silty clay loam
- % Clay:
- 30
- % Silt:
- 64
- % Sand:
- 6
- % Org. carbon:
- 1.86
- pH:
- 6.6
- CEC:
- 24.9 meq/100 g soil d.w.
- Details on matrix:
- The soil types utilized were sand (soil 1), sandy loam (soil 2), silt (soil 3) and silty clay loam (soil 4).
COLLECTION AND STORAGE
- Geographic location: Soil 1 at Naples, Florida; Soil 2 at Perry, Ohio; Soil 3 at Lake County, Tennessee; Soil 4 at Painesville, Ohio
- Soil preparation: The soils were air-dried in a fume hood for 24 hours and sieved as follows: Clay and silt soils were sieved through a 250-µ screen prior to use ; sand and sandy loam soils were sieved through a 590-µ screen prior to use. - Details on test conditions:
- TEST SOLUTION PREPARATION
Test solutions of 14C-labelled test substance were prepared at approximate concentrations of 0.5, 0.4, 0.2, and 0.1 µg/mL in 0.03N CaSO4. Test solutions of 14C-DDT were prepared at approximate concentrations of 0.05, 0.04, 0.02, and 0.01 µg/mL in 0.03N CaSO4 (pH 7.0).
DETERMINATION OF EQUILIBRATION TIME FOR 14C-LABELLED TEST SUBSTANCE
- Reaction vessel: 16mm x 125mm glass culture tubes (sealed screw caps)
- Amount of soil per treatment: 2.0 g (oven-dried equivalent weight)
- Procedure: To each soil sample in the culture tubes was added 8.0 mL of the 0.5 µg/mL 14C-labelled test substance solution. The samples were sealed with the screw caps, shaken by hand for 30 seconds, and then vigorously shaken in a shaker bath maintained at 25°C.
ADSORPTION OF THE TEST SUBSTANCE AND DDT
- Reaction vessel: 16mm x 125mm glass culture tubes (sealed screw caps)
- Amount of soil per treatment: 2.0 g (oven-dried equivalent weight)
- Number of reaction vessels/concentration: 3
- Procedure: Into each tube, 8.0 mL of a test solution were pipetted. The tubes were capped, hand shaken, and placed in the shaker bath for the appropriate equilibration time.
- Are the residues from the adsorption phase used for desorption: Yes
DESORPTION OF THE TEST SUBSTANCE AND DDT
- Procedure: A 4.0 mL portion of each supernatant was removed and a 4.0 mL portion of 0.03 N CaSO4 blank was added. Each sample was then shaken for an additional equilibration period equivalent to the adsorption phase. - Duration:
- 24 h
- Temp.:
- 25 °C
- Remarks:
- Applicable to all tests
- Duration:
- 24 h
- Temp.:
- 25 °C
- Remarks:
- Applicable to all tests
- Key result
- Sample No.:
- #1
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 850 L/kg
- Temp.:
- 20 °C
- Matrix:
- Sand
- % Org. carbon:
- 0.35
- Key result
- Sample No.:
- #2
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 1 100 L/kg
- Temp.:
- 20 °C
- Matrix:
- Sandy loam
- % Org. carbon:
- 1.86
- Key result
- Sample No.:
- #3
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 7 000 L/kg
- pH:
- 7.5
- Temp.:
- 20 °C
- Matrix:
- Silt
- % Org. carbon:
- 0.41
- Key result
- Sample No.:
- #4
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 1 400 L/kg
- pH:
- 6.6
- Temp.:
- 20 °C
- Matrix:
- Silty caly loam
- % Org. carbon:
- 1.86
- Adsorption and desorption constants:
- See Table 11 and Tbale 12 in 'Any other information on results incl. tables'
- Recovery of test material:
- See Table 1 in 'Any other information on results incl. tables'
- Concentration of test substance at end of adsorption equilibration period:
- See Table 2 - Table 9 in 'Any other information on results incl. tables'
- Concentration of test substance at end of desorption equilibration period:
- See Table 2 - Table 10 in 'Any other information on results incl. tables'
- Remarks on result:
- not measured/tested
- Remarks on result:
- not measured/tested
- Transformation products:
- not specified
- Details on results (Batch equilibrium method):
- An overview of the results is provided in Table 1 – Table 12 in 'Any other information on results incl. tables'.
With two of the soils, silt and silty clay loam, approximately 90% of the test substance in solution was adsorbed within 1 hour at each of the four concentrations. For the sandy loam and sand soils, approximately 84% and 47% of the the test substance in solution was adsorbed respectively; 8 hours were required to establish equilibrium. The adsorption constants (K) were 26, 29, 20, and 3 for the silty clay loam, silt, sandy loam, and sand soils respectively.
Only a slight amount of the adsorbed test substance was desorbed. For the three strongly adsorbing soils, 2 to 5% of the adsorbed the test substance was desorbed with each solvent dilution. Under these conditions between 10% and 28% of the adsorbed test substance was desorbed from sand. The data show that the binding potential of the test substance is high and indicate that the soil mobility is low. Therefore , based on adsorption and desorption properties, the test substance would not be expected to leach significantly. - Statistics:
- Not reported
- Validity criteria fulfilled:
- not specified
- Conclusions:
- The Kfoc values (adsorption) for soil 1(sand), soil 2(sandy loam), soil 3 (silt), and soil 4 (silty clay loam) were 850, 1100, 7000 and 1400 L/kg, respectively.
- Executive summary:
The adsorption and desorption of 14C-labelled test substance in soils were investigated. The soil types utilized were silty clay loam, silt, sand, and sandy loam soils. The study was conducted without following guideline but in compliance with GLP. The equilibration times were determined for each soil with a 0.5 µg/g (ppm) solution of 14C-labelled test substance. The adsorption/ desorption study was conducted at four concentrations (0.5, 0.4, 0.2, and 0.1 ppm). The adsorption and desorption of a standard reference compound (14C-lablled DDT) were determined on the same soils. With two of the soils, silt and silty clay loam, approximately 90% of the the test substance in solution was adsorbed within 1 hour at each of the four concentrations. For the sandy loam and sand soils, approximately 84% and 47% of the test substance in solution was adsorbed respectively; 8 hours were required to establish equilibrium. The adsorption constants (K) were 26, 29, 20, and 3 for the silty clay loam, silt , sandy loam, and sand soils respectively.
Only a slight amount of the adsorbed test substance was desorbed. For the three strongly adsorbing soils, 2 to 5% of the adsorbed the test substance was desorbed with each solvent dilution. Under these conditions between 10% and 28% of the adsorbed test substance was desorbed from sand. The data show that the binding potential of the test substance is high and indicate that the soil mobility is low. Therefore , based on adsorption and desorption properties, the test substance would not be expected to leach significantly. The Kfoc values (adsorption) for soil 1(sand), soil 2(sandy loam), soil 3 (silt), and soil 4 (silty clay loam) were 850, 1100, 7000 and 1400 L/kg, respectively.
- Endpoint:
- adsorption / desorption, other
- Remarks:
- batch equilibrium method
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 17 May 2005 to 15 Jul 2005
- 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:
- 2000
- GLP compliance:
- yes
- Type of method:
- batch equilibrium method
- Media:
- soil
- Radiolabelling:
- yes
- Test temperature:
- 19 - 21 °C
- Analytical monitoring:
- yes
- Details on sampling:
- SAMPLING INTERVAL
- Adsorption phase: Samples were taken after 48 hours equilibrium
- Desorption phase: Samples were taken after 24 hours equilibrium
- Mass balance: After adsorption - Matrix no.:
- #1
- Matrix type:
- clay
- % Clay:
- 55
- % Silt:
- 33
- % Sand:
- 12
- % Org. carbon:
- 10.2
- pH:
- 4.3
- Bulk density (g/cm³):
- 0.9
- Matrix no.:
- #2
- Matrix type:
- clay
- % Clay:
- 65
- % Silt:
- 27
- % Sand:
- 8
- % Org. carbon:
- 2.1
- pH:
- 4.5
- Bulk density (g/cm³):
- 1.2
- Matrix no.:
- #3
- Matrix type:
- loamy sand
- % Clay:
- 10
- % Silt:
- 88
- % Sand:
- 2
- % Org. carbon:
- 0.8
- pH:
- 4.7
- Bulk density (g/cm³):
- 1.5
- Matrix no.:
- #4
- Matrix type:
- clay loam
- % Clay:
- 40
- % Silt:
- 39
- % Sand:
- 21
- % Org. carbon:
- 2.1
- pH:
- 5.8
- Bulk density (g/cm³):
- 1.3
- Details on matrix:
- Four different soils were employed, which were characterized according to EMBRAPA (1999) as a Gleissolo Melanico Aluminico tipico (GM), Latossolo Vermelho Distroferrico tipico (LVdf), Neossolo Quartzarenico Órtico tipico (RQ), Argissolo Vermelho Eutroferrico chemossolico (PV). The choice of these soils was required by the sponsor, based on the “Instrução Normativa do IBAMA” (without number and date) which was under public consultation and was not published yet. According to the USDA (1998) the soils were characterized as a Typic Humaquept (GM), Rhodic Hapludox (LVdf), Typic Quartzipsamment (RQ) and Mollic Hapludalf (PV).
COLLECTION AND STORAGE
- Geographic location: 22°35’23” S and 47°35’69” W, 22°45’18” S and 47°53’75", 22°40’20” S and 47°37’31” W and 22°37’27” S and 47°36’67” W for GM, RQ, PV and LVdf soils, respectively. GM soil was sampled from a hygrophyte vegetation area. RQ and PV soils were sampled from pastures. LVdf soil was sampled from forest vegetation. All the soils were collected in the region from Piracicaba - SP.
- Pesticide history: No pesticides were applied to each of the places where the soils were collected.
- Sampling depth (cm): 0 - 20 cm depth
- Soil preparation: Using a 2 mm mesh. The moisture of the soils was maintained during the sieving.
- Soil analysis: Soil samples were analyzed for various chemical and physical properties that are considered to be important for the adsorption of chemicals in the soil (Chemical and physical properties see Table 1 in ‘Any other information on materials and methods incl. tables’). - Details on test conditions:
- TST SOLUTION PREPARATION
Solution A, C and D were used in pre-test, Solution B was used in the definitive test. The treatment solutions of the test substance for adsorption test is provided in Table 2 in ‘Any other information on materials and methods incl. tables’.
- Solution A: 10 mmol/L CaCl2 solution: 2.94 g of CaCl2.2H2O was added into 2.0 L volumetric flask, and volume was completed with deionized water.
- Solution B: 14C-labelled test substance was dissolved in 1000 µL of acetonitrile, resulting in a solution with radioactivity of 10.29 MBq/mL.
- Solution C: 94.5 µL of the solution B were diluted in 150 mL of 10 mmol/L CaCl2 solution, resulting in a final concentration of 4.0 µg/mL and radioactivity of 0.0085 Mq/mL.
- Solution D: 1.5 µL of the solution B were diluted in 50 mL of 10 mmol/L CaCl2 solution, resulting in a final concentration of 4.0 µg/mL and radioactivity of 0.0085 Mq/mL.
ADSORPTION
- Test vessel: Centrifuge tubes
- Amount of soil per treatment: 2 g
- Amount of treatment solution per treatment: 10.0, 5.0, 5.0 and 10.0 mL of treatment solutions were added in the tubes containing GM, LVdf, RQ and PV soil, respectively. (See Table 2 in ‘Any other information on materials and methods incl. tables’).
- Number of reaction vessels/concentration: 2
- Pre-equilibration: Pre-equilibrated in 90.0, 45.0, 45.0, and 90.0 mL of CaCl2 10 mmol/L for GM, LVdf, RQ and PV soils, respectively, for 48 h.
- Equilibration procedure: The tubes were tightly capped and were shaken vigorously for several seconds with a vortex mixer. Then, tubes were shaken horizontally, in a mechanical shaker (150 rpm, during 48 h, according to the results from pre-test), at constant temperature (19 - 21 °C).
- Are the residues from the adsorption phase used for desorption: Yes
DESORPTION
- Equilibration procedure: After adsorption step, the supernatant was decanted and a volume of CaCl2 0.01 mol/L equivalent to the volume used on the adsorption phase was added into the test tube to the soil from the adsorption phase. The tubes were shaken again, in a mechanical shaker (150 rpm, during 24 h), at constant temperature (19 - 21 °C).
MASS BALANCE
Two additional flasks for each soil were prepared with the highest concentration to determine the amount of parent molecule and degradates/impurities present in the soil by direct measurement (extraction and analysis). - Duration:
- 48 h
- Initial conc. measured:
- 0.014 other: µg/mL
- Temp.:
- 20 °C
- Remarks:
- Applied to all four soils
- Duration:
- 48 h
- Initial conc. measured:
- 0.079 other: µg/mL
- Temp.:
- 20 °C
- Remarks:
- Applied to all four soils
- Duration:
- 48 h
- Initial conc. measured:
- 0.168 other: µg/mL
- Temp.:
- 20 °C
- Remarks:
- Applied to all four soils
- Duration:
- 48 h
- Initial conc. measured:
- 0.386 other: µg/mL
- Temp.:
- 20 °C
- Remarks:
- Applied to all four soils
- Duration:
- 24 h
- Temp.:
- 20 °C
- Remarks:
- Applied to all four soils and four studied treatment solutions
- Key result
- Sample No.:
- #2
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 1 638 L/kg
- pH:
- 4.5
- Temp.:
- 20 °C
- Matrix:
- Clay
- % Org. carbon:
- 2.1
- Key result
- Sample No.:
- #3
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 1 953 L/kg
- pH:
- 4.7
- Temp.:
- 20 °C
- Matrix:
- Loamy sand
- % Org. carbon:
- 0.8
- Key result
- Sample No.:
- #4
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 17 923 L/kg
- pH:
- 5.8
- Temp.:
- 20 °C
- Matrix:
- Clay loam
- % Org. carbon:
- 2.1
- Sample No.:
- #1
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 1 543 L/kg
- pH:
- 4.3
- Temp.:
- 20 °C
- Matrix:
- Clay
- % Org. carbon:
- 10.2
- Remarks on result:
- other: The organic carbon and pH of soil content are not representative of global agriculture. Thus, the adsorption coefficient is not considered as key result.
- Sample No.:
- #1
- Phase system:
- solids-water in soil
- Type:
- other: Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 2 696 L/kg
- Temp.:
- 20 °C
- pH:
- 4.3
- Matrix:
- Clay
- % Org. carbon:
- 10.2
- Sample No.:
- #2
- Phase system:
- solids-water in soil
- Type:
- other: Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 4 202 L/kg
- Temp.:
- 20 °C
- pH:
- 4.5
- Matrix:
- Clay
- % Org. carbon:
- 2.1
- Sample No.:
- #3
- Phase system:
- solids-water in soil
- Type:
- other: Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 10 673 L/kg
- Temp.:
- 20 °C
- pH:
- 4.7
- Matrix:
- Loamy sand
- % Org. carbon:
- 0.8
- Sample No.:
- #4
- Phase system:
- solids-water in soil
- Type:
- other: Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 42 107 L/kg
- Temp.:
- 20 °C
- pH:
- 5.8
- Matrix:
- Clay loam
- % Org. carbon:
- 2.1
- Adsorption and desorption constants:
- See Table 9 and Table 10 in 'Any other information on results incl. tables'.
- Recovery of test material:
- See Table 8 in 'Any other information on results incl. tables'.
- Concentration of test substance at end of adsorption equilibration period:
- See Table 3 and Table 6 in 'Any other information on results incl. tables'.
- Concentration of test substance at end of desorption equilibration period:
- See Table 3 and Table 6 in 'Any other information on results incl. tables'.
- Sample no.:
- #1
- Duration:
- 48 h
- % Adsorption:
- 93.77
- Remarks on result:
- other: The mass balance was studied in two separated flasks with soil exposed to the highest concentration of the test substance. The % adsorption reuslt is the mean value.
- Sample no.:
- #2
- Duration:
- 48 h
- % Adsorption:
- 94.88
- Remarks on result:
- other: The mass balance was studied in two separated flasks with soil exposed to the highest concentration of the test substance. The % adsorption reuslt is the mean value.
- Sample no.:
- #3
- Duration:
- 48 h
- % Adsorption:
- 95.49
- Remarks on result:
- other: The mass balance was studied in two separated flasks with soil exposed to the highest concentration of the test substance. The % adsorption reuslt is the mean value.
- Sample no.:
- #4
- Duration:
- 48 h
- % Adsorption:
- 96.36
- Remarks on result:
- other:
- Remarks:
- The mass balance was studied in two separated flasks with soil exposed to the highest concentration of the test substance. The % adsorption reuslt is the mean value.
- Remarks on result:
- not measured/tested
- Transformation products:
- not specified
- Details on results (Batch equilibrium method):
- An overview of the results is provided in Table 3 – Table 10 in 'Any other information on results incl. tables'.
- Adsorption on the Surface of the Teflon Vessel and Stability of the test substance: There was no adsorption on the vessel. Based on the HPLC analysis, the test substance was found to be stable in the treatment solution over 48 hours.
- Adsorption/Desorption Isotherm Batch Experiments: The percentage of adsorption ranged from 69.43 to 79.62 % for GM soil, from 43.42 to 68.22 % for LVdf, from 31.86 to 45.02 % for RQ and from 74.04 to 85.15 % for PV soils.
- Mass balance: The total radioactivity of the test substance recovered for GM, LVdf, RQ and PV soil were 93.77, 94.88, 95.49 and 96.36 %, respectively. The amount of radioactivity found in the aqueous phase after adsorption was 35.39, 62.82, 74.64 and 30.47 % (mean value) of the dose applied for GM, LVdf, RQ and PV soils, respectively. The corresponding values for the soil extracts were 58.11, 30.67, 20.85 and 64.46 % for GM, LVdf, RQ and PV soils, respectively. Bound residues for the corresponding soils amounted to 0.27, 1.39, 0.0 and 1.43 for GM, LVdf, RQ and PV soils, respectively. - Statistics:
- Not reported
- Validity criteria fulfilled:
- yes
- Conclusions:
- There was a non-linear relationship between the solution and adsorbed phases in the adsorption and desorption of the test substance. The values of 1/n ranged from 0.76 to 0.86 for adsorption and 0.75 to 0.90 for desorption. The Kfoc values (adsorption) for GM, LVdf, RQ and PV soils were 1543, 1638, 1953 and 17923 L/kg, respectively. The Kfoc values (desorption) for GM, LVdf, RQ and PV soils were 2696, 4202, 10673 and 42107 L/kg, respectively. According to the mean values of Koc (5764 adsorption) and the McCall classification, the test substace is considered as immobile in the tested soils.
- Executive summary:
In this study the adsorption and desorption behavior of the test substance in a Gleissolo Melanico Aluminico tipico (GM), Latossolo Vermelho Distroferrico tipico (LVdf), Neossolo Quartzarenico Ortico tipico (RQ) Argissolo Vermelho Eutroferrico chemossdlico (PV) was investigated. The study was conducted in according to OECD TG 106 and in compliance with GLP criteria. A preliminary study showed that the adsorption equilibrium was attained after 48 hours of shaking for the four soils. Using an initial test substance concentration of 0.4µg/mL and a soi:solution ratio of 2 g soil:100 ml 0.01 M CaCl2, the adsorption was 71 % applied radioactivity for GM soil and 73 % for PV soil. For a soil to solution ratio of 2 g of soil: 50 mL 0.01 M CaCl2 the adsorption was 34% for RQ soil and 46 % for LVdf . No adsorption to the vessel was observed in the control samples. Degradation was not observed in any of the soils under test. In order to establish the isotherms, the following concentrations of l4C-labelled test substance were used: The definitive study was performed with five different 14C-labelled test substance concentrations: 0.0141, 0.0412, 0.0791, 0.1679 and 0.3859 pg/mL The assay was carried out in centrifuge tubes containing 2.0 g of soil sample and 100.0, 50.0, 50.0 and 100.0 mL of 10 mmol/L CaCl2 for GM, LVdf, RQ and PV soils respectively, being carried out in duplicate. The isotherms were fitted by the Freundlich mathematical modeling, and the Kd values were employed to calculate the Koc values.
Adsorption of the test substance was to some extent reversible in the tested soils, since the desorption coefficient was about 2.0 times the corresponding adsorption coefficient. The 14C-material balance comprising the aqueous phases, the soil extracts and non-extractable residues ranged from 93.77 % to 96.36% of the applied dose for the four tested soils. The amount of radioactivity found in the aqueous phase after adsorption was 35.39, 62.82, 74.64 and 30.47 % (mean value) of the dose applied for GM, LVdf, RQ and PV soils, respectively. The corresponding values for the soil extracts were 58.11, 30.67, 20.85 and 64.46 %. Analysis of aqueous phase after adsorption and soil extracts showed that 100.0 % of recovered radioactivity accounted for the parent compound in all soils.
There was a non-linear relationship between the solution and adsorbed phases in the adsorption and desorption of the test substance. The values of 1/n ranged from 0.76 to 0.86 for adsorption and 0.75 to 0.90 for desorption. The Kfoc values (adsorption) for GM, LVdf, RQ and PV soils were 1543, 1638, 1953 and 17923 L/kg, respectively. The Kfoc values (desorption) for GM, LVdf, RQ and PV soils were 2696, 4202, 10673 and 42107 L/kg, respectively. According to the mean values of Koc (5764 adsorption) and the McCall classification, the test substace is considered as immobile in the tested soils.
- Endpoint:
- adsorption / desorption, other
- Remarks:
- batch equilibrium method
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 17 Oct 2005 to 10 Nov 2005
- 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)
- Deviations:
- not specified
- GLP compliance:
- yes
- Type of method:
- batch equilibrium method
- Media:
- soil
- Radiolabelling:
- yes
- Test temperature:
- 20 ± 2 °C
- Analytical monitoring:
- yes
- Details on sampling:
- For 14C-labelled test substance treated soil, the samples were taken after 2 hours equilibration time.
For 14C-labelled M9 treated soil, the samples were taken after 24 hours equilibration time. - Matrix no.:
- #1
- Matrix type:
- clay loam
- % Clay:
- 33
- % Silt:
- 33
- % Sand:
- 34
- % Org. carbon:
- 1.04
- pH:
- 7
- CEC:
- 20.4 meq/100 g soil d.w.
- Matrix no.:
- #2
- Matrix type:
- silty clay loam
- % Clay:
- 38
- % Silt:
- 44
- % Sand:
- 18
- % Org. carbon:
- 0.58
- pH:
- 7.4
- CEC:
- 21.2 meq/100 g soil d.w.
- Details on matrix:
- COLLECTION AND STORAGE
- Geographic location: The Bologna soils were taken from the tile drain study site.
- Sampling depth (cm): 0 - 50 cm and 50 - 90 cm (soil #1 and soil #2)
- Soil preparation: Airdried and 2 mm sieved soils
- Prior to the start of the study, the soils were sterilised by gamma irradiation to minimise microbial degradation during the experiments.
- The moisture content of each soil was determined by oven-drying duplicate subsamples (approximately 40 g) at ca 105 °C overnight.
- Physicochemical characteristics of the soils were provided in Table 1 in 'Any other information on materials and methods incl. tables'.
- Details on test conditions:
- PREPARATION
- Soil Slurries Prior to Treatment: Prior to treatment with 14C-labelled test items, soil samples were equilibrated overnight in the respective tubes with aqueous CaCl2 (0.01M). Each tube contained oven-dry equivalent soil of 2 g (for test item) or 20 g (for M9) and sufficient 0.01M CaCl2 to bring the volume in the tube to 20 mL (for the test item) or 19 mL (for M9). Equilibration of the untreated soil slurries was by continuous mixing on an end-over-end shaker at approximately 25 rpm at 20 ± 2°C in order to gently agitate the samples. The use of aqueous CaCl2 solution prevented dispersion of the clay colloids and aided the centrifugation of the slurries.
- Treatment Solutions: The 14C-labelled test substance dispensed was dissolved in acetonitrile to produce a stock solution (1 mL) for the treatment of the soil samples at the nominal 3 mg/kg rate. 170 µL of this stock solution was added to 430 µL of acetonitrile in a small vial (resulting in total volume of 600 µL) to form the application solution for the treatment of the soil samples at the nominal 1 mg/kg rate.
The 14C-labelled M9 dispensed was dissolved in small amount of methanol (~ 500 µL), to which 14 mL of 0.01M CaCl2 aqueous was added to produce a stock solution, and used for the treatment of the soil samples at the nominal 3 mg/kg rate. 4 mL of this stock solution was added to 6 mL of 0.01M CaCl2 in a storage bottle (resulting in total volume of 10 mL) to form the application solution for the treatment of soil samples at the nominal 1 mg/kg rate.
APPLICATION OF 14C-LABELLED TEST ITEMS TO SLURRIES
- Aliquots of the 14C-labelled treatment solutions were applied to the pre-equilibrated soil : aqueous slurries. Fortification was carried out using Microman pipettes which dispenses accurately known volumes. For volumes of the application solutions added to each slurry. The exact application rates were determined from aliquots taken of each application solution during the treatment. These aliquots were diluted and quantified by LSC. TLC analysis of the application solutions for the treatment of soil samples at the nominal 3 mg/kg rate (post-application) was undertaken to determine the purity of the test items.
TREATMENT RATE
- 14C-labelled test substance: Experiments were conducted using two nominal treatment rates (0.1 and 0.3 µg/mL, equivalent to 1 and 3 mg/kg, respectively), with a soil : aqueous ratio of 1 : 10 (2 g soil : 20 mL aqueous) in glass tubes.
- 14C-labelled M9: Experiments were conducted using two nominal treatment rates (0.4 and 1.2 µg/mL), with a soil : aqueous ratio of 1 : 1 (20 g soil : 20 mL aqueous) in Teflon tubes.
- The results of actual application rate are provided in Table 2 in 'Any other information on materials and methods incl. tables'.
14C-LABELLED TEST SUBSTANCE EXPERIMENTS
- Procedure: For each depth of Bologna soil, two replicate soil slurries (for each treatment rate) were pre-equilibrated with aqueous 0.01M CaCl2 solution, and fortified with 50 µL of treatment solutions (in acetonitrile) to the slurries (20 mL of aqueous CaCl2). The slurries were placed on an end-over-end shaker (approx. 25 r.p.m.).
- Temperature: 20 ± 2°C
- Equilibration period: 2 hours
- Are the residues from the adsorption phase used for desorption: No
14C-LABELLED M9 EXPERIMENTS
- Procedure: For each depth of Bologna soil, two replicate soil slurries (for each treatment rate) were pre-equilibrated with aqueous 0.01M CaCl2 solution, and fortified with 1 mL of treatment solutions (in 0.01M CaCL2) to the slurries (19 mL of aqueous CaCl2), resulting in a final volume of 20 mL aqueous. The slurries were placed on an end-over-end shaker (approx. 25 r.p.m.)
- Temperature: 20 ± 2°C
- Equilibration period: 24 hours
- Are the residues from the adsorption phase used for desorption: No - Duration:
- 2 h
- Initial conc. measured:
- 0.1 other: µg/mL
- Temp.:
- 20 °C
- Remarks:
- tested on 14C-labelled test substance
- Duration:
- 2 h
- Initial conc. measured:
- 0.3 other: µg/mL
- Temp.:
- 20 °C
- Remarks:
- test oned 14C-labelled test substance
- Duration:
- 24 h
- Initial conc. measured:
- 0.4 other: µg/mL
- Temp.:
- 20 °C
- Remarks:
- tested on 14C-labelled M9
- Duration:
- 24 h
- Initial conc. measured:
- 1.2 other: µg/mL
- Temp.:
- 20 °C
- Remarks:
- tested on 14C-labelled M9
- Key result
- Sample No.:
- #1
- Type:
- Koc
- Value:
- 1 763 L/kg
- pH:
- 7
- Temp.:
- 20 °C
- Matrix:
- Clay Loam
- Remarks on result:
- other: For 14C-labelled test substance
- Key result
- Sample No.:
- #2
- Type:
- Koc
- Value:
- 2 938 L/kg
- pH:
- 7.4
- Temp.:
- 20 °C
- Matrix:
- Silty clay loam
- Remarks on result:
- other: For 14C-labelled test substance
- Sample No.:
- #1
- Type:
- Koc
- Value:
- 1.3 L/kg
- pH:
- 7
- Temp.:
- 20 °C
- Matrix:
- Clay loam
- Remarks on result:
- other: For 14C-labelled M9
- Sample No.:
- #2
- Type:
- Koc
- Value:
- 2 L/kg
- pH:
- 7.4
- Temp.:
- 20 °C
- Matrix:
- Silty clay loam
- Remarks on result:
- other: For 14C-labelled M9
- Adsorption and desorption constants:
- See Table 7 in 'Any other information on results incl. tables'.
- Recovery of test material:
- See Table 3 adn Table 4 in "'Any other information on results incl. tables'.
- Concentration of test substance at end of adsorption equilibration period:
- Not reported
- Remarks on result:
- other: See Table 3 and Table 4 in 'Any other information on results incl. tables'.
- Remarks on result:
- not measured/tested
- Transformation products:
- yes
- Details on results (Batch equilibrium method):
- An overview of the results is provided in Table 3 - Table 7 in "Any other information on results incl. tables"
- Application Rate: The measured values of the actual amount of 14C-labelled test substance and M9 added to the slurries were used in the calculation of the aqueous phase and soil concentrations. The actual application rates for the test substance experiment were 0.4 µg/mL (equates to a nominal 3 mg/kg rate) and 0.1 µg/mL (equates to a nominal 1 mg/kg rate). The actual application rates for the M9 experiment were 1.2 µg/mL (equates to a nominal 3 mg/kg rate) and 0.5 µg/mL(equates to a nominal 1 mg/kg rate).
- Mass Balance: For the test substance, the mass balances ranged from 99.5% - 103.4% of the applied radioactivity. For the tested M9, the mass balances ranged from 94.2% - 98.6% of the applied radioactivity.
- Stability of Test Items: The stability of test items in the soil : aqueous slurries was investigated by chromatographic analysis of the aqueous supernatants and soil extracts from the highest concentration treatment solutions (3 mg/kg). The analysis showed little or no degradation of the test items during the equilibration process. These data demonstrated that both the test items were stable under the experimental conditions. Thus for the purpose of calculation of the adsorption coefficients in this report, the radiochemical content of the soil and aqueous phase was assumed to be the applied test items.
- Adsorption of 14C-Labelled test substance to Soil: The average percentage of radiochemical in the various aqueous phases identified as 14C-labelled test substance was 91.4% (mean), with small amount baseline polar degradates observed. Analysis of soil extracts showed a higher percentage of purity, the average percentage of radiochemical in the various soil extracts identified as parent was 95.5% (mean). The initial concentrations of the test substance were calculated for each soil horizon by the distribution of radioactivity. Average Kd values after the adsorption step were found to be 18.4 and 17.0 for the 0 - 50 cm horizon and the 50 - 90 cm horizon respectively, with corresponding average Koc values of 1763 and 2938. The tube washing showed little adsorption to the glass wall during the adsorption process (0.3 - 0.7% recovered from the tube wash).
- Adsorption of 14C-Labelled M9 to Soil: The average percentage of radiochemical in the various aqueous phases identified as 14C-labelled M9 was 99.8% (mean), with no other degradates observed. Analysis of soil extracts showed a similar percentage of purity, the average percentage of radiochemical in the various soil extracts identified as parent was 98.8% (mean). The initial concentrations of M9 were calculated for each soil horizon by the distribution of radioactivity. Average Kd values after the adsorption step were found to be 0.014 and 0.012 for the 0 - 50 cm horizon and the 50 - 90 cm horizon respectively, with corresponding average Koc values of 1.3 and 2.0. - Statistics:
- Not reported
- Validity criteria fulfilled:
- yes
- Conclusions:
- The adsorption properties of 14C-labelled the test substance and its metabolite 14C-labelle M9 were studied in two depths of Bologna soil from the tile drain study. Average Kd values for the test substance experiments with 2 hours equilibration were 18.4 and 17.0 for the 0 - 50 cm horizon and the 50 - 90 cm horizon respectively. The corresponding Koc values were 1763 L/kg and 2938 L/kg respectively. Average Kd values for the M9 experiments were 0.014 and 0.012 for the 0 - 50 cm horizon and the 50 - 90 cm horizon respectively. The corresponding Koc values were 1.3 L/kg and 2.0 L/kg respectively.
- Executive summary:
The adsorption properties of 14C-labelled test substance and its metabolite M9 were studied in 2 different depths of Bologna soil (0- 50 cm and 50 - 90 cm horizons). The study was conducted in according to OECD TG 106 and in compliance with GLP criteria. 14C-labelled test substance was added to soil: aqueous slurries (resulting in a final nominal composition of 2 g of soil : 20 mL aqueous CaCl2) to achieve nominal rates of application of 1 mg/kg and 3 mg/kg, which equate to aqueous phase concentrations of 0.1 and 0.3 µg/mL. The treated slurries were equilibrated on an end-over-end shaker for 2 hrs at 20°C. The average percentage of radiochemical in the various aqueous phases identified as 14C-labelled test substance was 91.4% (mean), with small amount baseline polar degradates observed. Analysis of soil extracts showed a higher percentage of purity, the average percentage of radiochemical in the various soil extracts identified as parent was 95.5% (mean). The initial concentrations of the test substance were calculated for each soil horizon by the distribution of radioactivity. Average Kd values after the adsorption step were found to be 18.4 and 17.0 for the 0 - 50 cm horizon and the 50 - 90 cm horizon respectively, with corresponding average Koc values of 1763 L/kg and 2938 L/kg. The tube washing showed little adsorption to the glass wall during the adsorption process (0.3 - 0.7% recovered from the tube wash).
14C-labelled M9 was added to soil : aqueous slurries (resulting in a final nominal composition of 20 g of soil: 20 mL aqueous CaCl2) to achieve nominal rates of application of 0.4 mg kg and 1.2 mg/kg, which equate to aqueous phase concentrations of 0.4 and 1.2 µg/mL. The treated slurries were equilibrated on an end-over-end shaker for 24 hrs at 20°C. The average percentage of radiochemical in the various aqueous phases identified as 14C-labelled M9 was 99.8% (mean), with no other degradates observed. Analysis of soil extracts showed a similar percentage of purity, the average percentage of radiochemical in the various soil extracts identified as parent was 98.8% (mean).The initial concentrations of M9 were calculated for each soil horizon by the distribution of radioactivity. Average Kd values after the adsorption step were found to be 0.014 and 0.012 for the 0 - 50 cm horizon and the 50 - 90 cm horizon respectively, with corresponding average Koc values of 1.3 L/kg and 2.0 L/kg.
- Endpoint:
- adsorption / desorption, other
- Remarks:
- batch equilibrium method
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 09 Feb 2012 to 22 May 2013
- 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:
- 2000
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- other: EPA Guideline OPPTS 835.1230
- Version / remarks:
- 2008
- Deviations:
- no
- GLP compliance:
- yes (incl. QA statement)
- Type of method:
- batch equilibrium method
- Media:
- soil
- Radiolabelling:
- yes
- Test temperature:
- 20 ± 2 °C
- Analytical monitoring:
- yes
- Details on sampling:
- After the 2 h equilibration period, samples were removed from the shaker and centrifuged at ca 3000 rpm for 10 min. Following centrifugation, the supernatants were decanted, weighed and duplicate ca 1.0 g aliquots analysed by LSC. After 2 hours of desorption period, the sample was centrifuged at ca 3000 rpm for ca 10 min. Following centrifugation the supernatants were decanted, weighed and duplicate ca 1 g aliquots analysed by LSC.
- Mass balance: On completion of the desorption isotherm test, a mass balance was determined for all samples from 0.5 µg/mL concentration for all soil types. Additionally, mass balance was determined for all samples from all test concentrations for North Dakota. Each soil pellet was extracted. - Matrix no.:
- #1
- Matrix type:
- sandy loam
- % Clay:
- 23
- % Silt:
- 14
- % Sand:
- 63
- % Org. carbon:
- 2.5
- pH:
- 7.8
- CEC:
- 29.3 meq/100 g soil d.w.
- Matrix no.:
- #2
- Matrix type:
- silt loam
- % Clay:
- 20
- % Silt:
- 50
- % Sand:
- 30
- % Org. carbon:
- 1.7
- pH:
- 5.9
- CEC:
- 23.3 meq/100 g soil d.w.
- Matrix no.:
- #3
- Matrix type:
- silty clay
- % Clay:
- 39
- % Silt:
- 56
- % Sand:
- 6
- % Org. carbon:
- 1
- pH:
- 7.8
- CEC:
- 12.2 meq/100 g soil d.w.
- Matrix no.:
- #4
- Matrix type:
- sandy clay loam
- % Clay:
- 25
- % Silt:
- 24
- % Sand:
- 51
- % Org. carbon:
- 2.3
- pH:
- 6
- CEC:
- 18.9 meq/100 g soil d.w.
- Matrix no.:
- #5
- Matrix type:
- loam
- % Clay:
- 12
- % Silt:
- 43
- % Sand:
- 45
- % Org. carbon:
- 2.6
- pH:
- 7
- CEC:
- 10.8 meq/100 g soil d.w.
- Details on matrix:
- Detailed information of tested soils are provided in Table 1 in Any other information on materials and methods, incl. tables'.
COLLECTION AND STORAGE
- Soil preparation: The soils were sieved (2 mm) in a fresh state (i.e. not dried) then air dried.
- Storage: The soils were stored air dried throughout the study. After air drying samples were gamma irradiated.
- Details on test conditions:
- Detailed information on experimental design is provided in Table 2 and Table 3 in 'Any other information on materials and methods, incl. tables'.
- Test set-up: Ten replicates of each soil (ca 0.5 g oven dry equivalent) were weighed into polypropylene centrifuge tubes and equilibrated with 50 mL of 0.01M CaCl2, for a 1:100 ratio, overnight on an end-over-end shaker. In all cases the exact amount of soil and 0.01M CaCl2 added to each sample was weighed accurately. [14C]-labelled test substance treatment solutions were prepared in acetonitrile. For each concentration, treatment solution (50 µL) was added to samples following the initial overnight equilibration period. Following application, the treated vessels were placed on an end-over-end shaker for the predetermined 2 h equilibration period for the adsorption step. The samples were maintained at a temperature of 20 ± 2°C in the dark. Immediately after removing the adsorption supernatant following the adsorption phase, an amount (exact weight recorded) of fresh 0.01M CaCl2 solution approximately equivalent to that removed was added to each of the soil samples. The soil pellets were re-suspended and the samples placed on an end-over-end shaker at 20 ± 2°C in the dark for ca 2 h (the desorption equilibrium period). - Duration:
- 2 h
- Temp.:
- 20 °C
- Remarks:
- Nominal concentrations were 0.0, 0.25, 0.50, 0.75 and 1.00 µg a.i./mL
- Duration:
- 2 h
- Temp.:
- 20 °C
- Key result
- Sample No.:
- #1
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 2 965 L/kg
- pH:
- 7.8
- Temp.:
- 20 °C
- Matrix:
- Sandy loam
- % Org. carbon:
- 2.5
- Key result
- Sample No.:
- #2
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 2 751 L/kg
- pH:
- 5.9
- Temp.:
- 20 °C
- Matrix:
- Silt loam
- % Org. carbon:
- 1.7
- Key result
- Sample No.:
- #3
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 4 559 L/kg
- pH:
- 7.8
- Temp.:
- 20 °C
- Matrix:
- Silty clay
- % Org. carbon:
- 1
- Key result
- Sample No.:
- #4
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 1 409 L/kg
- pH:
- 6
- Temp.:
- 20 °C
- Matrix:
- Sandy clay loam
- % Org. carbon:
- 2.3
- Key result
- Sample No.:
- #5
- Type:
- Koc
- Remarks:
- Freundlich Coefficients
- Value:
- 1 042 L/kg
- pH:
- 7
- Temp.:
- 20 °C
- Matrix:
- Loam
- % Org. carbon:
- 2.6
- Sample No.:
- #1
- Phase system:
- solids-water in soil
- Type:
- other: Koc - Desorption Freundlich Coefficients
- Value:
- 5 083 L/kg
- Temp.:
- 20 °C
- Matrix:
- Sandy loam
- % Org. carbon:
- 2.5
- Sample No.:
- #2
- Phase system:
- solids-water in soil
- Type:
- other: Koc - Desorption Freundlich Coefficients
- Value:
- 5 272 L/kg
- Temp.:
- 20 °C
- Matrix:
- Silt loam
- % Org. carbon:
- 1.7
- Sample No.:
- #3
- Phase system:
- solids-water in soil
- Type:
- other: Koc - Desorption Freundlich Coefficients
- Value:
- 14 894 L/kg
- Temp.:
- 20 °C
- Matrix:
- Silty clay
- % Org. carbon:
- 1
- Sample No.:
- #4
- Phase system:
- solids-water in soil
- Type:
- other: Koc - Desorption Freundlich Coefficients
- Value:
- 2 308 L/kg
- Temp.:
- 20 °C
- Matrix:
- Sandy clay loam
- % Org. carbon:
- 2.3
- Sample No.:
- #5
- Phase system:
- solids-water in soil
- Type:
- other: Koc - Desorption Freundlich Coefficients
- Value:
- 1 410 L/kg
- Temp.:
- 20 °C
- Matrix:
- Loam
- % Org. carbon:
- 2.6
- Adsorption and desorption constants:
- See Table 11 and Table 12 'Any other information on results incl. tables'.
- Recovery of test material:
- See Table 10 in 'Any other information on results incl. tables'.
- Concentration of test substance at end of adsorption equilibration period:
- See Table 5 - Table 9 in 'Any other information on results incl. tables'.
- Concentration of test substance at end of desorption equilibration period:
- See Table 5 - Table 9 in "Any other information on results incl. tables"
- Remarks on result:
- other: See Table 10 in 'Any other information on results incl. tables'.
- Remarks on result:
- other: See Table 10 in 'Any other information on results incl. tables'.
- Transformation products:
- not specified
- Details on results (Batch equilibrium method):
- Preliminart test result and an overview of the result was provided in Table 4 'Any other information on results incl. tables'.
- Adsorption isotherm results: The average Kd and KOC values ranged from 32.88-153.84 and 1303-6154 mL/g respectively. The values for the Freundlich adsorption isotherm parameters, KF and KFOC ranged from 27.10-74.13 and 1042-4559 mL/g, respectively. The value for the Freundlich constant, 1/n, ranged from 0.75 - 0.94.
- Desorption isotherm results: The average desorption partition coefficients, Kd,des and KOC,des values ranged from 84.95-301.11 and 3694-26744 mL/g, respectively. The values for the Freundlich desorption isotherm parameters, KF,des and KFOC,des ranged from 36.66-148.94 and 1410-14894 mL/g, respectively. The values for the Freundlich constant, 1/n, ranged from 0.77-0.97.
- Confirmation of test item stability during the isotherm experiments: To verify the test item stability, TLC analysis was performed on samples (adsorption and desorption supernatants and combined soil extracts) from all samples for all concentrations in the highest Kd soil type (North Dakota) and the 0.5 µg/mL concentration samples for the remaining soils The results showed that [14C]-labelled test substance was stable in the test system during the course of the experiments. In the TLC analysis [14C]-labelled test substance accounted for a mean of 96.0% of radioactivity in the TLC images (range 70.5 – 109.1%). [14C]-labelled test substance accounted for 70.5 – 91.3% of the radioactivity in the TLC analysis of the adsorption and desorption supernatants from the North Dakota 0.01 µg/mL concentration. The low results are due to low levels of radioactivity in the samples.
- Mass balance of the isotherm experiments: The mass balance for each test soil was determined for both replicates from all test concentrations for the highest Kd soil type (North Dakota) and on both replicates from the 0.5 µg/mL concentration samples for the remaining soils. The mass balance was determined as the sum of radioactivity in the adsorption and desorption supernatants, the soil pellet extracts and the amount remaining in the soil after extraction. The mean mass balance from all soils was 95.0% (range 86.8 – 105.0%). Four samples had a mass balance of <90% (range 85.2 – 89.3%) and a single sample had a mass balance > 110%, at 113.8%. Mass balance results for this study were quantitative but in a minority of samples (no discernable pattern observed) were slightly out with acceptance criteria (90 -110%). This was deemed to have no effect on the overall outcomes for the study. - Statistics:
- not reported
- Validity criteria fulfilled:
- yes
- Conclusions:
- The adsorption and desorption properties of [14C]-labelled test substance were studied in five different soils: North Dakota (sandy loam, USA), White Swan (silt loam, USA), Marsillargues (silty clay; France), 18 Acres (sandy clay loam; UK) and Gartenacker (loam; Switzerland). The calculated Freundlich adsorption coefficients (KF) ranged from 27.10 to 74.13 mL/g, while the 1/n values ranged from 0.75 to 0.94. When corrected for the organic carbon content of the soils, the resultant KFOC values ranged from 1042 to 4559 mL/g. The mean partition coefficients Kd ranged from 32.88 to 153.84 mL/g with the corresponding KOC of 1303 to 6154 mL/g.
The calculated Freundlich desorption coefficients (KF,des) ranged from 36.66 to 148.94 mL/g, while the 1/n values ranged from 0.77 to 0.97. When corrected for the organic carbon content of the soils, the resultant KFOC des values ranged from 1410 to 14894 mL/g. The mean partition coefficients Kd des ranged from 84.95 to 301.11 mL/g with the corresponding KOC of 3724 to 26744 mL/g. Using the McCall Classification scale to assess a chemical’s potential mobility in soil (based on its KFOC), chlorothalonil can be classified as having slight mobility in Marsillargues, North Dakota and White Swan soil and low mobility in 18 Acres and Gartenacker soil. - Executive summary:
The adsorption/desorption characteristics of [14C]-labelled test substance were studied in 5 different soils: North Dakota (sandy loam, USA), White Swan (silt loam, USA), Marsillargues (silty clay; France), 18 Acres (sandy clay loam; UK) and Gartenacker (loam; Switzerland) using a standard batch equilibrium method, in the dark at 20°C. The study was conducted in according to OCED TG 106 and EPA guideline OPPTS 835.1230 and it was in compliance with GLP. Treatment solutions of [14C]-labelled test substance were prepared in acetonitrile. The chemical was added to soil:aqueous slurries (resulting in a final nominal compositions of 0.5 g of soil: 50 mL aqueous 0.01M CaCl2 for all five soils) to achieve five nominal rates of application (0.01, 0.25, 0.5, 0.75, 1.0 µg/mL). The soil adsorption coefficients Kd and KOC, together with the Freundlich adsorption constants KF and KFOC, were determined for each soil.
The adsorption phase was followed by a single desorption phase to determine the reversibility of adsorption. Following preliminary tests, an adsorption equilibration time of 2 hours and a desorption equilibration period of 2 hours were selected for the definitive test. Recovery of the applied radioactivity was determined, for all concentrations of North Dakota soil and all soils at a concentration of 0.5 µg/mL, by radioassay of the adsorption supernatants, desorption supernatants and soil extracts with combustion of soil residues. Stability was verified by thin layer chromatography (TLC) analysis of the adsorption and desorption supernatants and soil extracts from the same samples as used to determine mass balance. For all soils the recovery of radioactivity was quantitative. The mean mass balance from all soils was 95.0% (range 86.8 – 105.0%). Four samples had a mass balance of < 90% (range 85.2 – 89.3%) and a single sample had a mass balance > 110%, at 113.8%. Mass balance results for this study were quantitative but in a minority of samples (no discernable pattern observed) were slightly out with acceptance criteria (90 - 110%). This was deemed to have no effect on the overall outcomes for the study.
The calculated Freundlich adsorption coefficients (KF) ranged from 27.10 to 74.13 mL/g, while the 1/n values ranged from 0.75 to 0.94. When corrected for the organic carbon content of the soils, the resultant KFOC values ranged from 1042 to 4559 mL/g. The mean partition coefficients Kd ranged from 32.88 to 153.84 mL/g with the corresponding KOC of 1303 to 6154 mL/g. The calculated Freundlich desorption coefficients (KF,des) ranged from 36.66 to 148.94 mL/g, while the 1/n values ranged from 0.77 to 0.97. When corrected for the organic carbon content of the soils, the resultant KFOC des values ranged from 1410 to 14894 mL/g. The mean partition coefficients Kd des ranged from 84.95 to 301.11 mL/g with the corresponding KOC des of 3694 to 26744 mL/g. Using the McCall Classification scale to assess a chemical’s potential mobility in soil (based on its KFOC), the test substance can be classified as having slight mobility in Marsillargues, North Dakota and White Swan soil and low mobility in 18 Acres and Gartenacker soil.
Referenceopen allclose all
Table 1. 14C-labelled test substance adsorbed by soil after shaking for various times
Time (hours) |
14C-labelled test substance in supernatant (dpm) |
Percent test substance adsorbed |
||
Silty clay loam initial: 38.906 dpm |
1 |
2.290 |
94.1 |
|
3 |
2.751 |
92.9 |
||
5 |
2.508 |
93.6 |
||
8 |
2.892 |
92.6 |
||
Silt initial: 38.906 dpm |
1 |
3.594 |
90.8 |
|
3 |
3.696 |
90.5 |
||
5 |
3.887 |
90 |
||
8 |
3.927 |
89.9 |
||
Sandy loam initial: 38.906 dpm |
1 |
7.298 |
79.2 |
|
3 |
6.986 |
81.2 |
||
5 |
6.233 |
82.0 |
||
8 |
6.217 |
84.0 |
||
24 |
6.217 |
84.0 |
||
Sand initial: 38.906 dpm |
1 |
23.892 |
38.6 |
|
3 |
22.378 |
42.5 |
||
5 |
21.496 |
44.7 |
||
8 |
20.494 |
47.3 |
||
24 |
20.514 |
47.3 |
||
Table 2. Adsorption and desorption of the test substance from silty clay loam (mean of 6 assays)
Initial concentration / Measured value of concentration (ppm) |
Adsorption (ppm) |
First desorption (ppm) |
Second desorption (ppm) |
|||
Equilibrium concentration in solution |
Adsorbed on soil |
Concentration in solution |
Desorbed From soil |
Concentration in solution |
Desorbed From soil |
|
0.5 / 0.518 |
0.037 |
1.926 |
0.027 |
0.0353 |
0.027 |
0.0547 |
0.4 / 0.425 |
0.031 |
1.578 |
0.024 |
0.0338 |
0.023 |
0.0456 |
0.2 / 0.205 |
0.012 |
0.772 |
0.009 |
0.014 |
0.01 |
0.0192 |
0.1 / 0.101 |
0.005 |
0.385 |
0.005 |
0.0088 |
0.005 |
0.0088 |
Table 3. Adsorption and desorption of the test substance from silt (mean of 6 assays)
Initial concentration / Measured value of concentration (ppm) |
Adsorption (ppm) |
First desorption (ppm) |
Second desorption (ppm) |
|||
Equilibrium concentration in solution |
Adsorbed on soil |
Concentration in solution |
Desorbed From soil |
Concentration in solution |
Desorbed From soil |
|
0.5 / 0.518 |
0.043 |
1.901 |
0.03 |
0.0344 |
0.03 |
0.0502 |
0.4 / 0.425 |
0.028 |
1.587 |
0.023 |
0.0337 |
0.023 |
0.0467 |
0.2 / 0.205 |
0.012 |
0.77 |
0.01 |
0.0148 |
0.01 |
0.0186 |
0.1 / 0.101 |
0.006 |
0.379 |
0.005 |
0.007 |
0.005 |
0.0095 |
Table 4. Adsorption and desorption of the test substance from sandy loam (mean of 6 assays)
Initial concentration / Measured value of concentration (ppm) |
Adsorption (ppm) |
First desorption (ppm) |
Second desorption (ppm) |
|||
Equilibrium concentration in solution |
Adsorbed on soil |
Concentration in solution |
Desorbed From soil |
Concentration in solution |
Desorbed From soil |
|
0.5 / 0.518 |
0.081 |
1.748 |
0.059 |
0.0734 |
0.058 |
0.1159 |
0.4 / 0.425 |
0.058 |
1.466 |
0.047 |
0.0699 |
0.047 |
0.0949 |
0.2 / 0.205 |
0.028 |
0.707 |
0.023 |
0.0341 |
0.022 |
0.0438 |
0.1 / 0.101 |
0.014 |
0.347 |
0.011 |
0.017 |
0.01 |
0.0186 |
Table 5. Adsorption and desorption of the test substance from sand (mean of 6 assays)
Initial concentration / Measured value of concentration (ppm) |
Adsorption (ppm) |
First desorption (ppm) |
Second desorption (ppm) |
|||
Equilibrium concentration in solution |
Adsorbed on soil |
Concentration in solution |
Desorbed From soil |
Concentration in solution |
Desorbed From soil |
|
0.5 / 0.518 |
0.245 |
1.091 |
0.154 |
0.1257 |
0.154 |
0.3096 |
0.4 / 0.425 |
0.201 |
0.895 |
0.123 |
0.0907 |
0.123 |
0.2454 |
0.2 / 0.205 |
0.083 |
0.486 |
0.055 |
0.0517 |
0.054 |
0.1077 |
0.1 / 0.101 |
0.037 |
0.256 |
0.025 |
0.0244 |
0.024 |
0.0484 |
Table 6. Adsorption and desorption of the test substance from clay loam (mean of 6 assays)
Initial concentration / Measured value of concentration (ppm) |
Adsorption (ppm) |
First desorption (ppm) |
Second desorption (ppm) |
|||
Equilibrium concentration in solution |
Adsorbed on soil |
Concentration in solution |
Desorbed From soil |
Concentration in solution |
Desorbed From soil |
|
0.5 / 0.518 |
0.0006 |
0.2068 |
0.0005 |
0.0007 |
0.0004 |
0.0005 |
0.4 / 0.425 |
0.0005 |
0.158 |
0.0004 |
0.0005 |
0.0003 |
0.0004 |
0.2 / 0.205 |
0.0002 |
0.0836 |
0.0002 |
0.0003 |
0.0001 |
** |
0.1 / 0.101 |
0.0001 |
0.0404 |
0.0001 |
0.0001 |
0.0001 |
** |
Table 7. Adsorption and desorption of DDT from silt (mean of 6 assays)
Initial concentration / Measured value of concentration (ppm) |
Adsorption (ppm) |
First desorption (ppm) |
Second desorption (ppm) |
|||
Equilibrium concentration in solution |
Adsorbed on soil |
Concentration in solution |
Desorbed From soil |
Concentration in solution |
Desorbed From soil |
|
0.05 / 0.0523 |
0.0016 |
0.2027 |
0.0009 |
0.0005 |
0.0006 |
<0.0001 ppm |
0.04 / 0.0400 |
0.0013 |
0.1549 |
0.0007 |
0.0004 |
0.0005 |
<0.0001 ppm |
0.02 / 0.0212 |
0.0006 |
0.0821 |
0.0004 |
0.0002 |
0.0002 |
<0.0001 ppm |
0.01 / 0.0102 |
0.0003 |
0.0396 |
0.0002 |
<0.0001 ppm |
0.0001 |
<0.0001 ppm |
Table 8. Adsorption and desorption of DDT from sandy loam (mean of 6 assays)
Initial concentration / Measured value of concentration (ppm) |
Adsorption (ppm) |
First desorption (ppm) |
Second desorption (ppm) |
|||
Equilibrium concentration in solution |
Adsorbed on soil |
Concentration in solution |
Desorbed From soil |
Concentration in solution |
Desorbed From soil |
|
0.05 / 0.0523 |
0.00024 |
0.20828 |
0.00014 |
0.00009 |
0.00010 |
<0.00001 ppm |
0.04 / 0.0400 |
0.00016 |
0.15925 |
0.00013 |
0.00017 |
0.00010 |
<0.00001 ppm |
0.02 / 0.0212 |
0.00008 |
0.08431 |
0.00006 |
0.00008 |
0.00004 |
<0.00001 ppm |
0.01 / 0.0102 |
0.00003 |
0.0408 |
0.00002 |
0.00001 |
0.00002 |
<0.00001 ppm |
Table 9. Adsorption and desorption of DDT from Sand (mean of 6 assays)
Initial concentration / Measured value of concentration (ppm) |
Adsorption (ppm) |
First desorption (ppm) |
Second desorption (ppm) |
|||
Equilibrium concentration in solution |
Adsorbed on soil |
Concentration in solution |
Desorbed From soil |
Concentration in solution |
Desorbed From soil |
|
0.05 / 0.0523 |
0.0022 |
0.2007 |
0.0011 |
0.0003 |
0.0007 |
<0.0001 ppm |
0.04 / 0.0400 |
0.0016 |
0.1536 |
0.0009 |
0.0003 |
0.0005 |
<0.0001 ppm |
0.02 / 0.0212 |
0.0008 |
0.0616 |
0.0004 |
0.0002 |
0.0003 |
<0.0001 ppm |
0.01 / 0.0102 |
0.0004 |
0.0392 |
0.0002 |
<0.0001 ppm |
0.0001 |
<0.0001 ppm |
Table 10. Percent of adsorbed test substance desorbed with each solvent dilution (mean value of 6 assays)
Initial concentration (ppm) |
Silty clay loam desorption |
Silty desorption |
Sandy loam desorption |
Sand desorption |
||||
#1 |
#2 |
#1 |
#2 |
#1 |
#2 |
#1 |
#2 |
|
0.05 |
1.8 |
2.8 |
1.8 |
3.2 |
4.2 |
6.6 |
11.5 |
28.4 |
0.04 |
2.1 |
2.9 |
2.1 |
2.9 |
4.8 |
6.5 |
10.1 |
27.4 |
0.02 |
1.8 |
2.5 |
1.9 |
2.4 |
4.8 |
6.2 |
10.6 |
22.2 |
0.01 |
2.3 |
2.3 |
1.8 |
2.5 |
4.9 |
5.4 |
9.5 |
18.9 |
Table 11. Freundlich isotherm constants and selected soil properties for the test substance
Constant /property |
Silty clay loam |
Silt |
Sandy loam |
Sand |
K (Adsorption constant) |
26 |
29 |
20 |
3 |
1/n (slope) |
0.7919 |
0.8334 |
0.9441 |
0.7525 |
Correlation coefficient |
0.9989 |
0.9852 |
0.9932 |
0.9985 |
Percent organic matter |
3.2 |
0.7 |
3.2 |
0.6 |
Q |
813 |
4143 |
625 |
500 |
Note: adsorption coefficient (Q) was reported as a function of soil organic matter content.
Table 12. Freundlich isotherm constants and selected soil properties for DDT
Constant /property |
Silty clay loam |
Silt |
Sandy loam |
Sand |
K (Adsorption constant) |
124 |
89 |
162 |
72 |
1/n (slope) |
0.8674 |
0.9484 |
0.7972 |
0.9575 |
Correlation coefficient |
0.9901 |
0.9963 |
0.9976 |
0.9979 |
Percent organic matter |
3.2 |
0.7 |
3.2 |
0.6 |
Q |
3.906 |
12.714 |
6.063 |
12.000 |
Note: adsorption coefficient (Q) was reported as a function of soil organic matter content.
Table 3. Concentrations of the test substance in the aqueous (Ce) and adsorbed (x/m) phases in the GM soil after adsorption and desorption steps.
|
Input concentration (µg/mL) |
Cea(µg/mL) |
x/mb(µg/g) |
||||
R1c |
R2 |
Mean |
R1 |
R2 |
Mean |
||
Adsorption |
0.141 |
0.0029 |
0.0028 |
0.0029 |
0.5586 |
0.5616 |
0.5601 |
0.0412 |
0.0098 |
0.0088 |
0.0093 |
1.5680 |
1.6177 |
1.5929 |
|
0.0791 |
0.0185 |
0.0185 |
0.0185 |
3.029 |
3.029 |
3.029 |
|
0.1679 |
0.0441 |
0.0431 |
0.0436 |
6.1909 |
6.241 |
6.2159 |
|
0.3859 |
0.1158 |
0.1201 |
0.118 |
13.5051 |
13.2894 |
13.3973 |
|
Desorption |
0.0109 |
0.0016 |
0.0015 |
0.0016 |
0.4804 |
0.4875 |
0.484 |
0.0307 |
0.0043 |
0.0043 |
0.0043 |
1.3644 |
1.4082 |
1.3863 |
|
0.0587 |
0.0095 |
0.0096 |
0.0095 |
2.5766 |
2.5693 |
2.5729 |
|
0.1213 |
0.0212 |
0.0207 |
0.0209 |
5.1701 |
5.2436 |
5.2069 |
|
0.263 |
0.0489 |
0.0502 |
0.0495 |
11.221 |
10.9488 |
11.0849 |
|
a: Aqueous phase.
b: Adsorbed phase.
c: Replicate
Table 4. Concentrations of the test substance in the aqueous (Ce) and adsorbed (x/m) phases in the LVdf soil after adsorption and desorption steps.
|
Input concentration (µg/mL) |
Cea(µg/mL) |
x/mb(µg/g) |
||||
R1c |
R2 |
Mean |
R1 |
R2 |
Mean |
||
Adsorption |
0.0141 |
0.0042 |
0.0047 |
0.0045 |
0.2459 |
0.2339 |
0.2399 |
0.0412 |
0.0179 |
0.0153 |
0.0166 |
0.5827 |
0.6472 |
0.615 |
|
0.0791 |
0.0359 |
0.0359 |
0.0359 |
1.0789 |
1.0795 |
1.0792 |
|
0.1679 |
0.0673 |
0.0833 |
0.0753 |
2.5151 |
2.1157 |
2.3154 |
|
0.3859 |
0.2193 |
0.2174 |
0.2184 |
41,665 |
4.212 |
4.1892 |
|
Desorption |
0.0096 |
0.0015 |
0.0015 |
0.0015 |
0.2121 |
0.2006 |
0.2063 |
0.0231 |
0.0059 |
0.0046 |
0.0052 |
0.4491 |
0.545 |
0.4971 |
|
0.0428 |
0.0111 |
0.0181 |
0.0146 |
0.8319 |
0.6486 |
0.7402 |
|
0.0988 |
0.0198 |
0.0226 |
0.0212 |
2.0886 |
1.638 |
1.8633 |
|
0.1707 |
0.0544 |
0.0516 |
0.053 |
3.1464 |
3.2642 |
3.2053 |
|
a: Aqueous phase.
b: Adsorbed phase.
c: Replicate
Table 5. Concentrations of the test substance in the aqueous (Ce) and adsorbed (x/m) phases in the RQ soil after adsorption and desorption steps.
|
Input concentration (µg/mL) |
Cea(µg/mL) |
x/mb(µg/g) |
||||
R1c |
R2 |
Mean |
R1 |
R2 |
Mean |
||
Adsorption |
0.0141 |
0.0077 |
0.0078 |
0.0077 |
0.16 |
0.157 |
0.1584 |
0.0412 |
0.0252 |
0.0247 |
0.0249 |
0.3998 |
0.4116 |
0.4057 |
|
0.0791 |
0.047 |
0.0472 |
0.0471 |
0.8022 |
0.7969 |
0.7995 |
|
0.1679 |
0.109 |
0.1138 |
0.1114 |
1.4732 |
1.3533 |
1.4133 |
|
0.3859 |
0.2635 |
0.2625 |
0.263 |
3.0614 |
3.0865 |
3.074 |
|
Desorption |
0.0096 |
0.0011 |
0.0013 |
0.0012 |
0.1458 |
0.1385 |
0.1422 |
0.0231 |
0.0042 |
0.0032 |
0.0037 |
0.3556 |
0.394 |
0.3748 |
|
0.0428 |
0.0107 |
0.0107 |
0.0107 |
0.5924 |
0.5866 |
0.5895 |
|
0.0988 |
0.0173 |
0.0157 |
0.0165 |
1.205 |
1.1354 |
1.1702 |
|
0.1707 |
0.0376 |
0.0366 |
0.0371 |
2.7969 |
2.8445 |
2.8207 |
|
a: Aqueous phase.
b: Adsorbed phase.
c: Replicate
Table 6. Concentrations of the test substance in the aqueous (Ce) and adsorbed (x/m) phases in the PV soil after adsorption and desorption steps.
|
Input concentration (µg/mL) |
Cea(µg/mL) |
x/mb(µg/g) |
||||
R1c |
R2 |
Mean |
R1 |
R2 |
Mean |
||
Adsorption |
0.0141 |
0.002 |
0.0021 |
0.0021 |
0.6014 |
0.5965 |
0.599 |
0.0412 |
0.0075 |
0.0075 |
0.0075 |
1.683 |
1.6854 |
1.6842 |
|
0.0791 |
0.0138 |
0.0137 |
0.0137 |
3.2634 |
3.2709 |
3.2671 |
|
0.1679 |
0.0338 |
0.0331 |
0.0335 |
6.7044 |
6.7393 |
6.7218 |
|
0.3859 |
0.1005 |
0.0998 |
0.1002 |
14.2691 |
14.3061 |
14.2876 |
|
Desorption |
0.0096 |
0.0007 |
0.0007 |
0.0007 |
0.5668 |
0.5657 |
0.5662 |
0.0231 |
0.0027 |
0.0026 |
0.0027 |
1.5525 |
1.5593 |
1.5559 |
|
0.0428 |
0.0059 |
0.0057 |
0.0058 |
2.9808 |
2.9976 |
2.9892 |
|
0.0988 |
0.0162 |
0.0152 |
0.0157 |
5.9214 |
6.0049 |
5.9632 |
|
0.1707 |
0.0449 |
0.0448 |
0.0448 |
12.1224 |
12.1658 |
12.1441 |
|
a: Aqueous phase.
b: Adsorbed phase.
c: Replicate
Table 7. Percentage of the test substance adsorbed and desorbed in soils
|
|
Adsorbed (% of applied) |
Desorbed (% of applied) |
||||
Soil |
Input concentration (µg/mL) |
R1 |
R2 |
Mean |
R1 |
R2 |
Mean |
GM |
0.0141 |
79.41 |
79.84 |
79.62 |
11.71 |
11.12 |
11.41 |
0.0412 |
76.19 |
78.61 |
77.4 |
10.7 |
10.9 |
10.8 |
|
0.0791 |
76.6 |
76.6 |
76.6 |
12.54 |
12.72 |
12.63 |
|
0.1679 |
73.74 |
74.33 |
74.04 |
13.03 |
12.73 |
12.88 |
|
0.3859 |
69.99 |
68.87 |
69.43 |
13.28 |
13.63 |
13.46 |
|
LVdf |
0.0141 |
69.93 |
66.51 |
68.22 |
11.1 |
11.11 |
11.11 |
0.0412 |
56.63 |
62.9 |
59.76 |
14.97 |
11.63 |
13.3 |
|
0.0791 |
54.57 |
54.6 |
54.58 |
14.71 |
24.01 |
19.36 |
|
0.1679 |
59.91 |
50.4 |
55.16 |
12.45 |
14.22 |
13.34 |
|
0.3859 |
43.18 |
43.66 |
43.42 |
15.25 |
14.46 |
14.85 |
|
RQ |
0.0141 |
45.5 |
44.55 |
45.02 |
8.51 |
9.73 |
9.12 |
0.0412 |
38.86 |
40.00 |
39.43 |
11.37 |
8.64 |
10.00 |
|
0.0791 |
40.57 |
40.3 |
40.44 |
14.37 |
14.41 |
14.39 |
|
0.1679 |
35.09 |
32.24 |
33.67 |
11.04 |
10.05 |
10.55 |
|
0.3859 |
31.73 |
31.99 |
31.86 |
10.89 |
10.63 |
10.76 |
|
PV |
0.0141 |
85.5 |
84.8 |
85.15 |
5.32 |
4.78 |
5.05 |
0.0412 |
81.78 |
81.9 |
81.84 |
6.81 |
6.59 |
6.7 |
|
0.0791 |
82.53 |
82.72 |
82.62 |
7.62 |
7.38 |
7.5 |
|
0.1679 |
79.85 |
80.27 |
80.06 |
9.91 |
9.32 |
9.62 |
|
0.3859 |
73.95 |
74.14 |
74.04 |
12.05 |
12.01 |
12.03 |
|
R1 and R2 = replicates
Table 8 Mass balance of the test substance for the soils
|
Replicate |
Input concentration (µg/mL) |
Aqueus phase1 |
Extracted2 |
Combusted3 |
Total recovery |
GM |
R1 |
0.3940 |
36.18 |
57.36 |
0.54 |
94.08 |
R2 |
0.3940 |
34.61 |
58.86 |
0.00 |
93.47 |
|
mean |
|
35.39 |
58.11 |
0.27 |
93.77 |
|
LVdf |
R1 |
0.3940 |
63.14 |
30.36 |
1.93 |
95.43 |
R2 |
0.3940 |
62.50 |
30.98 |
0.84 |
94.32 |
|
mean |
|
62.82 |
30.67 |
1.39 |
94.88 |
|
RQ |
R1 |
0.3940 |
74.44 |
20.87 |
0.00 |
95.31 |
R2 |
0.3940 |
74.84 |
20.83 |
0.00 |
95.67 |
|
mean |
|
74.64 |
20.85 |
0.00 |
95.49 |
|
PV |
R1 |
0.3940 |
30.21 |
65.37 |
2.85 |
98.43 |
R2 |
0.3940 |
30.73 |
63.55 |
0.00 |
94.28 |
|
mean |
|
30.47 |
64.46 |
1.43 |
96.36 |
1. Radioactivity in the equilibrium solution of adsorption test.
2. Radioactivity extracted.
3. Radioactivity remaining in soil (after extraction)
Table 9. Freundlich parameters (Kf and 1/n) for adsorption and desorption of the test substance in the soils
Soil |
Replicate |
Adsorption |
Desorption |
||||
Kf [(µg/g)(mL/µg)1/n] |
1/n |
R2 |
Kf [(µg/g)(mL/µg)1/n] |
1/n |
R2 |
||
GM |
R1 |
91.51 |
0.87 |
0.99 |
174.36 |
0.91 |
0.99 |
R2 |
85.18 |
0.85 |
0.99 |
157.96 |
0.88 |
0.99 |
|
mean |
88.35 |
0.86 |
0.99 |
166.16 |
0.9 |
0.99 |
|
LVdf |
R1 |
14.47 |
0.76 |
0.97 |
34.83 |
0.8 |
0.96 |
R2 |
13.73 |
0.75 |
0.99 |
21.41 |
0.72 |
0.89 |
|
mean |
14.1 |
0.76 |
0.98 |
28.12 |
0.76 |
0.93 |
|
RQ |
R1 |
9.57 |
0.84 |
0.99 |
33.02 |
0.82 |
0.97 |
R2 |
9.18 |
0.83 |
0.99 |
36.85 |
0.83 |
0.96 |
|
mean |
9.38 |
0.84 |
0.99 |
34.94 |
0.83 |
0.97 |
|
PV |
R1 |
102.29 |
0.83 |
0.99 |
127.13 |
0.74 |
0.99 |
R2 |
108.52 |
0.84 |
0.99 |
124.7 |
0.73 |
0.99 |
|
mean |
105.41 |
0.84 |
0.99 |
125.92 |
0.74 |
0.99 |
|
Table 10. Distribution coefficient (Kd), distribution coefficient normalized to soil organic carbon (Koc), organic matter (Kom) and clay (Kciay) for adsorption and desorption of the test substance in the soils
Soil |
Replicate |
Kd |
Koc |
Kom |
Kclay |
mL/g |
|||||
Adsorption |
|||||
GM |
R1 |
154.69 |
1516.6 |
879.7 |
281.3 |
R2 |
160.16 |
1570.2 |
910.8 |
291.2 |
|
mean |
157.43 |
1543.39 |
895.2 |
286.2 |
|
LVdf |
R1 |
35.43 |
1687.3 |
978.7 |
54.5 |
R2 |
33.37 |
1589.1 |
921.7 |
51.3 |
|
mean |
34.4 |
1638.2 |
950.2 |
52.9 |
|
RQ |
R1 |
15.79 |
1974.1 |
1143.3 |
157.9 |
R2 |
15.46 |
1932 |
1120.6 |
154.6 |
|
mean |
15.62 |
1953.1 |
1132.9 |
156.2 |
|
PV |
R1 |
219.11 |
17960.1 |
10417.7 |
547.8 |
R2 |
218.22 |
17886.5 |
10375.00 |
545.6 |
|
mean |
218.66 |
17923.3 |
10396.3 |
546.6 |
|
Desorption |
|||||
GM |
R1 |
273.2 |
2678.6 |
1553.7 |
496.7 |
R2 |
276.8 |
2714 |
1574.2 |
503.3 |
|
mean |
275.00 |
2696.3 |
1563.9 |
500.0 |
|
LVdf |
R1 |
91.4 |
4353.9 |
2525.5 |
140.6 |
R2 |
85.1 |
4050.6 |
2349.6 |
130.9 |
|
mean |
88.2 |
4202.2 |
2437.5 |
135.7 |
|
RQ |
R1 |
83.2 |
10403.6 |
6034.6 |
832 |
R2 |
87.5 |
10941.7 |
6346.7 |
878 |
|
mean |
85.4 |
10672.6 |
6190.6 |
854 |
|
PV |
R1 |
498 |
40821.2 |
23678.2 |
1245 |
R2 |
529.4 |
43391.8 |
25169.3 |
1323.5 |
|
mean |
513.7 |
42106.5 |
24423.7 |
1284.3 |
|
Table 3. Mass Balance for the test substance Experiments (2 Hrs Equilibration)
(a) As % of Applied:
Sample ID |
% of applied radioactivity in: |
||||
Adsorption supernatant removed |
Soil extract |
Tube wash |
Soil pellet |
Total |
|
Rate: 0.1 µg/mL (0 - 50 cm) |
|||||
5JH038/1 |
30.5 |
64.9 |
0.7 |
4.6 |
100.8 |
05JH038/2 |
30.6 |
67.6 |
0.4 |
4.8 |
103.4 |
Rate: 0.1 µg/mL (50 - 90 cm) |
|||||
5JH038/3 |
32.1 |
67 |
0.4 |
3.2 |
102.6 |
05JH038/4 |
28.7 |
67.8 |
0.3 |
3.2 |
100 |
Rate: 0.4 µg/mL (0 - 50 cm) |
|||||
05JH038/5 |
35.7 |
60 |
0.6 |
3.8 |
100.1 |
05JH038/6 |
35.6 |
59.5 |
0.6 |
3.8 |
99.5 |
Rate: 0.4 µg/mL (50 - 90 cm) |
|||||
05JH038/7 |
37.3 |
60.4 |
0.3 |
2.5 |
100.5 |
05JH038/8 |
37.2 |
59.1 |
0.6 |
2.7 |
99.6 |
(b) As Amount of Radioactivity:
Sample ID |
Bq radioactivity in: |
||||
Adsorption supernatant removed |
Soil extract |
Tube wash |
Soil pellet |
Total |
|
Rate: 0.1 µg/mL (0 - 50 cm) |
|||||
5JH038/1 |
4875.9 |
10380 |
115 |
736.1 |
16107 |
05JH038/2 |
4894.7 |
10800 |
60 |
772.2 |
16526.9 |
Rate: 0.1 µg/mL (50 - 90 cm) |
|||||
5JH038/3 |
5129.1 |
10705 |
65 |
506.8 |
16405.9 |
05JH038/4 |
3973.7 |
9400 |
45 |
442.4 |
13861 |
Rate: 0.4 µg/mL (0 - 50 cm) |
|||||
05JH038/5 |
19857.8 |
33350 |
330 |
2097.3 |
55635.1 |
05JH038/6 |
19771.5 |
33075 |
310 |
2108.2 |
55264.7 |
Rate: 0.4 µg/mL (50 - 90 cm) |
|||||
05JH038/7 |
20733 |
33560 |
155 |
1380.7 |
55828.7 |
05JH038/8 |
20680.7 |
32820 |
345 |
1487.6 |
55333.3 |
Table 4. Mass Balance for M9 experiments
(a) As % of Applied:
Sample ID |
% of applied radioactivity in: |
|||
Adsorption supernatant removed |
Soil extract |
Soil pellet |
Total |
|
Rate: 0.5 µg/mL (0 - 50 cm) |
||||
5JH038/1 |
60.1 |
25.3 |
11.2 |
96.6 |
05JH038/2 |
59.8 |
23.5 |
13.4 |
96.7 |
Rate: 0.5 µg/mL (50 - 90 cm) |
||||
5JH038/3 |
59.5 |
20.9 |
15.7 |
96.1 |
05JH038/4 |
59.5 |
20.9 |
15.4 |
95.8 |
Rate: 1.2 µg/mL (0 - 50 cm) |
||||
05JH038/5 |
59.9 |
24.2 |
13.7 |
97.8 |
05JH038/6 |
61 |
25.2 |
12.4 |
98.6 |
Rate: 1.2 µg/mL (50 - 90 cm) |
||||
05JH038/7 |
61 |
17.4 |
15.8 |
94.2 |
05JH038/8 |
60.3 |
18.1 |
18.1 |
96.5 |
(b) As Amount of Radioactivity:
Sample ID |
Bq radioactivity in: |
|||
Adsorption supernatant removed |
Soil extract |
Soil pellet (a) |
Total |
|
Rate: 0.5 µg/mL (0 - 50 cm) |
||||
5JH038/1 |
18037.8 |
7610 |
3358.8 |
29006.6 |
05JH038/2 |
17949.4 |
7055 |
4035.8 |
29040.2 |
Rate: 0.5 µg/mL (50 - 90 cm) |
||||
5JH038/3 |
17882.8 |
6270 |
471209 |
28865.8 |
05JH038/4 |
17861.9 |
6285 |
4615.8 |
28762.7 |
Rate: 1.2 µg/mL (0 - 50 cm) |
||||
05JH038/5 |
44877.3 |
18135 |
10229.9 |
73242.2 |
05JH038/6 |
45660.4 |
18880 |
9274.3 |
73814.8 |
Rate: 1.2 µg/mL (50 - 90 cm) |
||||
05JH038/7 |
45686.2 |
13000 |
11828.1 |
70514.4 |
05JH038/8 |
45168.5 |
13535 |
13572 |
72275.5 |
(a) The high amount of unextracted activity wasprobably due to inadequate mixing as a result of the limited volume of the tube, the large amount of soil and the small volume of solvent which could be used
Table 5. TLC Analysis of Samples from the High Rate Experiments
(a) the test substance: 0.4µg/mL Treatment Rate (2 Hours Equilibration)
Sample ID |
Soil Horizon |
% of test substance (a) in |
|
Aqueous |
Soil extract |
||
05JH038/5 |
0 - 50 cm |
90.79 |
96.25 |
05JH038/6 |
91.21 |
96.27 |
|
05JH038/7 |
50 - 90 cm |
92.1 |
95.37 |
05JH038/8 |
91.55 |
94.11 |
|
(b) M9: 1.2µg/mL Treatment Rate
Sample ID |
Soil Horizon |
% of M9 (a) in |
|
Aqueous |
Soil extract |
||
05JH038/21 |
0 - 50 cm |
99.67 |
99.19 |
|
99.69 |
98.98 |
|
05JH038/23 |
50 - 90 cm |
99.8 |
98.42 |
|
99.85 |
98.68 |
|
(a) % purity as measured by the TLC.
Table 6. Concentrations of the test substance and M9 Equivalents (Based on Distribution of Radioactivity)
(a) The test substance
Soil Horizon |
Treatment |
Aqueous Phase |
Soil Phase |
Percentage of Applied |
0 - 50 cm |
0.1 |
0.0363 |
0.7482 |
67 |
0.0363 |
0.7485 |
|||
0.4 |
0.1479 |
2.3858 |
62 |
|
0.1471 |
2.3938 |
|||
50 - 90 cm |
0.1 |
0.0387 |
0.7248 |
61 |
0.0322 |
0.6417 |
|||
0.4 |
0.1564 |
2.3006 |
60 |
|
0.1558 |
2.3062 |
Note: Above values are from the 2 hours equilibration experiments.
(b) M9
Soil Horizon |
Treatment |
Aqueous Phase |
Soil Phase |
Percentage of Applied |
0 - 50 cm |
0.5 |
0.4705 |
0.0078 |
2 |
0.4701 |
0.0081 |
|||
1.2 |
1.1773 |
0.0152 |
1 |
|
1.1832 |
0.0093 |
|||
50 - 90 cm |
0.5 |
0.4703 |
0.0079 |
2 |
0.4693 |
0.0089 |
|||
1.2 |
1.1839 |
0.0086 |
1 |
Table 7 Summary of Kd and Koc Values from the Adsorption Step
(a)14C-labelled test substance (2 hours equilibration)
Soil Horizon |
Nominal rate applied Aqueous phase (µg/mL) |
Kd |
Koc |
0 - 50 cm |
0.1 |
20.6 |
1973 |
0.4 |
16.2 |
1552 |
|
Average |
18.4 |
1763 |
|
50 - 90 cm |
0.1 |
19.3 |
3331 |
0.4 |
14.8 |
2544 |
|
Average |
17.0 |
2938 |
(b)14C-labelled M9
Soil Horizon |
Nominal rate applied Aqueous phase (µg/mL) |
Kd |
Koc |
0 - 50 cm |
0.5 |
0.017 |
1.6 |
1.2 |
0.01 |
1 |
|
Average |
0.014 |
1.3 |
|
50 - 90 cm |
0.5 |
0.018 |
3.1 |
1.2 |
0.0056 |
1 |
|
Average |
0.0 |
2 |
Table 4. Results of preliminary tests
Solubility Tests |
The solubility of the test item was checked at 1 µg/mL in 0.01M CaCl2 including acetonitrile as a co-solvent (0.1% by volume) |
Soil:Solution Ratio test |
Preliminary tests were performed at soil:solution ratios of 1:10, 1:50 and 1:100 w/v.
An optimum ratio of 1:100 (w/v) was established for all soil types (between 20-80% adsorption). |
Time to Adsorption Equilibrium |
An adsorption equilibrium time of 2 h was established following analysis of samples at 0.5, 1, 2, and 4 h.
Range of adsorption at 2 h: 17.2 – 57.6%. |
Time to Desorption Equilibrium |
A desorption equilibrium time of 2 h was established following analysis of samples at 0.5, 1, 2 h, following an initial adsorption period of 2 h.
Range of desorption at 2 h (as % of test item adsorbed): 31.1 – 53.5%. |
Stability during Equilibrium Time Determination |
The test item was stable for the duration of the test. In TLC analysis [14C]-labelled test substance accounted for 92.4% - 101.1% of radioactivity in the adsorption and desorption equilibrium samples. |
Table 5. Concentrations of the test substance Equivalents for the Adsorption and Desorption Isotherms for North Dakota
Nominal Test Concentration (µg/mL) |
Replicate |
Adsorption |
Desorption |
||||
Ce (µg/mL) |
Cs (µg/g) |
% Adsorbed |
Ce, des (µg/mL) |
Cs, des (µg/g) |
% desorbed as % of the adsorbed |
||
0.010 |
1 |
0.002 |
0.700 |
77.95 |
0.001 |
0.606 |
13.41 |
2 |
0.002 |
0.707 |
77.73 |
0.001 |
0.614 |
13.16 |
|
Mean |
0.002 |
0.704 |
77.84 |
0.001 |
0.610 |
13.29 |
|
0.250 |
1 |
0.107 |
12.660 |
51.94 |
0.036 |
9.045 |
28.56 |
2 |
0.102 |
12.454 |
54.55 |
0.035 |
9.087 |
27.04 |
|
Mean |
0.105 |
12.557 |
53.25 |
0.036 |
9.066 |
27.80 |
|
0.500 |
1 |
0.207 |
22.280 |
54.40 |
0.073 |
16.343 |
26.65 |
2 |
0.218 |
22.666 |
51.86 |
0.074 |
16.211 |
28.48 |
|
Mean |
0.213 |
22.473 |
53.13 |
0.074 |
16.277 |
27.57 |
|
0.750 |
1 |
0.334 |
33.187 |
50.03 |
0.106 |
24.150 |
27.23 |
2 |
0.341 |
30.617 |
49.06 |
0.108 |
21.515 |
29.73 |
|
Mean |
0.338 |
31.902 |
49.55 |
0.107 |
22.833 |
28.48 |
|
1.000 |
1 |
0.450 |
44.446 |
49.14 |
0.142 |
31.636 |
28.82 |
2 |
0.479 |
45.496 |
46.54 |
0.158 |
29.618 |
34.90 |
|
Mean |
0.465 |
44.971 |
47.84 |
0.150 |
30.627 |
31.86 |
|
Ce Concentration in the solution at adsorption equilibrium
Cs Concentration in the soil at adsorption equilibrium
Ce, des Concentration in the solution at desorption equilibrium
Cs, des Concentration in the soil at desorption equilibrium
Table 6. Concentrations of the test substance Equivalents for the Adsorption and Desorption Isotherms for White Swan
Nominal Test Concentration (µg/mL) |
Replicate |
Adsorption |
Desorption |
||||
Ce (µg/mL) |
Cs (µg/g) |
% Adsorbed |
Ce, des (µg/mL) |
Cs, des (µg/g) |
% desorbed as % of the adsorbed |
||
0.010 |
1 |
0.005 |
0.397 |
44.32 |
0.002 |
0.214 |
46.15 |
2 |
0.005 |
0.394 |
44.77 |
0.002 |
0.212 |
46.19 |
|
Mean |
0.005 |
0.396 |
44.55 |
0.002 |
0.213 |
46.17 |
|
0.250 |
1 |
0.150 |
7.734 |
32.58 |
0.040 |
3.866 |
50.01 |
2 |
0.153 |
7.230 |
30.39 |
0.039 |
3.403 |
52.93 |
|
Mean |
0.152 |
7.482 |
31.49 |
0.040 |
3.635 |
51.47 |
|
0.500 |
1 |
0.307 |
16.042 |
31.50 |
0.073 |
8.759 |
45.40 |
2 |
0.302 |
14.633 |
34.08 |
0.079 |
7.940 |
45.74 |
|
Mean |
0.305 |
15.338 |
32.79 |
0.076 |
8.350 |
45.57 |
|
0.750 |
1 |
0.442 |
22.964 |
34.48 |
0.110 |
13.079 |
43.04 |
2 |
0.448 |
20.212 |
33.31 |
0.117 |
10.603 |
47.54 |
|
Mean |
0.445 |
21.588 |
33.90 |
0.114 |
11.841 |
45.29 |
|
1.000 |
1 |
0.537 |
34.703 |
39.95 |
0.196 |
16.000 |
47.89 |
2 |
0.548 |
32.160 |
39.11 |
00194 |
16.359 |
49.13 |
|
Mean |
0.543 |
31.432 |
39.53 |
0.195 |
16.180 |
48.51 |
|
Ce Concentration in the solution at adsorption equilibrium
Cs Concentration in the soil at adsorption equilibrium
Ce, des Concentration in the solution at desorption equilibrium
Cs, des Concentration in the soil at desorption equilibrium
Table 7. Concentrations of the test substance Equivalents for the Adsorption and Desorption Isotherms for Marsillargues
Nominal Test Concentration (µg/mL) |
Replicate |
Adsorption |
Desorption |
||||
Ce (µg/mL) |
Cs (µg/g) |
% Adsorbed |
Ce, des (µg/mL) |
Cs, des (µg/g) |
% desorbed as % of the adsorbed |
||
0.010 |
1 |
0.005 |
0.429 |
43.64 |
0.001 |
0.336 |
21.88 |
2 |
0.005 |
0.370 |
45.00 |
0.001 |
0.289 |
21.72 |
|
Mean |
0.005 |
0.400 |
44.32 |
0.001 |
0.313 |
21.80 |
|
0.250 |
1 |
0.150 |
7.546 |
32.28 |
0.018 |
5.942 |
21.26 |
2 |
0.154 |
5.768 |
29.37 |
0.016 |
4.656 |
19.26 |
|
Mean |
0.152 |
6.657 |
30.83 |
0.017 |
5.299 |
20.26 |
|
0.500 |
1 |
0.307 |
16.007 |
33.45 |
0.034 |
13.250 |
17.22 |
2 |
0.302 |
14.374 |
33.28 |
0.034 |
11.658 |
18.90 |
|
Mean |
0.305 |
15.191 |
33.37 |
0.034 |
12.454 |
18.06 |
|
0.750 |
1 |
0.443 |
21.230 |
34.61 |
0.070 |
15.782 |
25.66 |
2 |
0.446 |
20.839 |
33.01 |
0.069 |
15.166 |
27.23 |
|
Mean |
0.445 |
21.036 |
33.81 |
0.070 |
15.474 |
26.45 |
|
1.000 |
1 |
0.537 |
32.627 |
40.13 |
0.153 |
19.877 |
39.08 |
2 |
0.548 |
32.493 |
38.69 |
0.157 |
18.913 |
41.80 |
|
Mean |
0.543 |
32.560 |
39.41 |
0.155 |
19.395 |
40.44 |
|
Ce Concentration in the solution at adsorption equilibrium
Cs Concentration in the soil at adsorption equilibrium
Ce, des Concentration in the solution at desorption equilibrium
Cs, des Concentration in the soil at desorption equilibrium
Table 8. Concentrations of the test substance Equivalents for the Adsorption and Desorption Isotherms for 18 Acres
Nominal Test Concentration (µg/mL) |
Replicate |
Adsorption |
Desorption |
||||
Ce (µg/mL) |
Cs (µg/g) |
% Adsorbed |
Ce, des (µg/mL) |
Cs, des (µg/g) |
% desorbed as % of the adsorbed |
||
0.010 |
1 |
0.006 |
0.309 |
33.41 |
0.001 |
0.224 |
27.21 |
2 |
0.006 |
0.266 |
33.86 |
0.002 |
0.105 |
60.40 |
|
Mean |
0.006 |
0.288 |
33.64 |
0.002 |
0.165 |
43.81 |
|
0.250 |
1 |
0.165 |
5.031 |
24.87 |
0.034 |
2.285 |
54.58 |
2 |
0.169 |
4.688 |
23.09 |
0.033 |
2.032 |
56.66 |
|
Mean |
0.167 |
4.860 |
23.98 |
0.034 |
2.159 |
55.62 |
|
0.500 |
1 |
0.340 |
11.105 |
26.11 |
0.063 |
5.967 |
46.27 |
2 |
0.346 |
9.786 |
23.89 |
0.064 |
4.732 |
51.64 |
|
Mean |
0.343 |
10.446 |
25.00 |
0.064 |
5.350 |
48.96 |
|
0.750 |
1 |
0.499 |
15.675 |
25.31 |
0.098 |
7.706 |
50.83 |
2 |
0.497 |
15.425 |
26.37 |
0.105 |
7.340 |
52.42 |
|
Mean |
0.498 |
15.55 |
25.84 |
0.102 |
7.524 |
51.63 |
|
1.000 |
1 |
0.609 |
27.384 |
31.54 |
0.182 |
11.164 |
59.23 |
2 |
0.601 |
29.703 |
33.12 |
0.189 |
12.410 |
58.22 |
|
Mean |
0.605 |
28.692 |
32.50 |
0.186 |
11.787 |
58.73 |
|
Table 9. Concentrations of the test substance Equivalents for the Adsorption and Desorption Isotherms for Gartenacker
Nominal Test Concentration (µg/mL) |
Replicate |
Adsorption |
Desorption |
||||
Ce (µg/mL) |
Cs (µg/g) |
% Adsorbed |
Ce, des (µg/mL) |
Cs, des (µg/g) |
% desorbed as % of the adsorbed |
||
0.010 |
1 |
0.006 |
0.326 |
35.23 |
0.001 |
0.240 |
26.45 |
2 |
0.006 |
0.260 |
32.95 |
0.001 |
0.188 |
27.59 |
|
Mean |
0.006 |
0.293 |
34.09 |
0.001 |
0.214 |
27.02 |
|
0.250 |
1 |
0.179 |
3.619 |
17.76 |
0.030 |
1.264 |
65.07 |
2 |
0.177 |
3.991 |
18.56 |
0.029 |
1.578 |
60.48 |
|
Mean |
0.178 |
3.805 |
18.16 |
0.030 |
1.421 |
62.78 |
|
0.500 |
1 |
0.354 |
9.473 |
21.76 |
0.053 |
5.184 |
45.27 |
2 |
0.354 |
9.397 |
21.29 |
0.057 |
4.845 |
48.45 |
|
Mean |
0.354 |
9.435 |
21.53 |
0.055 |
5.015 |
46.86 |
|
0.750 |
1 |
0.515 |
13.172 |
22.20 |
0.099 |
5.579 |
57.65 |
2 |
0.520 |
13.491 |
22.36 |
0.104 |
6.504 |
51.79 |
|
Mean |
0.518 |
13.332 |
22.28 |
0.102 |
6.042 |
54.72 |
|
1.000 |
1 |
0.584 |
28.342 |
33.62 |
0.163 |
14.006 |
50.58 |
2 |
0.592 |
26.755 |
33.21 |
0.192 |
10.757 |
59.79 |
|
Mean |
0.588 |
27.549 |
33.42 |
0.178 |
12.382 |
55.19 |
|
Ce Concentration in the solution at adsorption equilibrium
Cs Concentration in the soil at adsorption equilibrium
Ce, des Concentration in the solution at desorption equilibrium
Cs, des Concentration in the soil at desorption equilibrium
Table 10. Mass Balance in the Adsorption/Desorption Isotherm Experiments
Soil |
Nominal Test Conc. (µg/mL) |
Replicate |
% of Applied Radioactivity in : |
||||
Adsorption Supernatant |
Desorption Supernatant |
Combined Soil Extracts |
Soil Pellet |
Total |
|||
North Dakota |
0.01 |
1 |
25.1 |
11.0 |
50.5 |
9.6 |
96.2 |
2 |
24.3 |
10.7 |
70.4 |
8.4 |
113.8 |
||
Mean |
24.7 |
10.9 |
60.5 |
9.0 |
105.0 |
||
0.25 |
1 |
46.8 |
15.3 |
31.5 |
3.9 |
97.5 |
|
2 |
44.4 |
15.2 |
34.5 |
3.8 |
97.9 |
||
Mean |
45.6 |
15.3 |
33.0 |
3.9 |
97.7 |
||
0.50 |
1 |
44.6 |
15.4 |
32.4 |
3.7 |
96.1 |
|
2 |
47.4 |
15.3 |
31.9 |
3.5 |
98.1 |
||
Mean |
46.0 |
15.4 |
32.2 |
3.6 |
97.1 |
||
0.75 |
1 |
48.4 |
15.0 |
27.7 |
3.3 |
94.4 |
|
2 |
50.1 |
15.2 |
27.8 |
3.2 |
96.3 |
||
Mean |
49.3 |
15.1 |
27.8 |
3.3 |
95.4 |
||
1.00 |
1 |
49.7 |
15.2 |
25.4 |
2.5 |
92.8 |
|
2 |
52.6 |
17.0 |
24.4 |
2.7 |
96.7 |
||
Mean |
51.2 |
16.1 |
24.9 |
2.6 |
94.8 |
||
Marsillargues |
0.50 |
1 |
65.4 |
7.0 |
12.1 |
0.7 |
85.2 |
2 |
65.8 |
7.2 |
14.9 |
0.4 |
88.3 |
||
Mean |
65.6 |
7.1 |
13.5 |
0.6 |
86.8 |
||
18 Acres |
1 |
73.0 |
13.1 |
6.6 |
0.3 |
93.0 |
|
2 |
75.0 |
13.6 |
7.4 |
0.4 |
96.4 |
||
Mean |
74.0 |
13.4 |
7.0 |
0.4 |
94.7 |
||
Gartenacker |
1 |
76.8 |
11.3 |
4.9 |
0.7 |
93.7 |
|
2 |
77.3 |
11.8 |
4.8 |
0.7 |
94.6 |
||
Mean |
77.1 |
11.6 |
4.9 |
0.7 |
94.2 |
||
White Swan |
1 |
67.4 |
15.5 |
5.9 |
0.5 |
89.3 |
|
2 |
64.9 |
16.6 |
6.5 |
0.6 |
88.6 |
||
Mean |
66.2 |
16.1 |
6.2 |
0.6 |
89.0 |
||
Table 11. Summary of Kd, KOC, KF, KFOC and 1/n Values from the Adsorption Step
Soil |
Nominal Rate Applied Aqueous Phase (µg/mL) |
Partition Coefficients |
Freundlich Coefficients |
|||
Kd |
KOC |
KF |
KFOC |
1/n |
||
North Dakota |
0.010 |
351.75 |
14070 |
74.13 |
2965 |
0.75 |
0.250 |
120.21 |
4809 |
||||
0.500 |
105.80 |
4232 |
||||
0.750 |
94.58 |
3783 |
||||
1.000 |
96.88 |
3875 |
||||
Overall Average: |
153.84 |
6154 |
||||
White Swan |
0.010 |
79.10 |
4653 |
46.774 |
2751 |
0.91 |
0.250 |
49.41 |
2906 |
||||
0.500 |
50.35 |
2962 |
||||
0.750 |
48.54 |
2855 |
||||
1.000 |
57.94 |
3408 |
||||
Overall Average: |
57.07 |
3357 |
||||
Marsillargues |
0.010 |
79.90 |
7990 |
45.59 |
4559 |
0.91 |
0.250 |
43.88 |
4388 |
||||
0.500 |
49.87 |
4987 |
||||
0.750 |
47.32 |
4732 |
||||
1.000 |
61.03 |
6003 |
||||
Overall Average: |
56.20 |
5620 |
||||
18 Acres |
0.010 |
47.92 |
2083 |
32.40 |
1409 |
0.94 |
0.250 |
29.12 |
1266 |
||||
0.500 |
30.47 |
1325 |
||||
0.750 |
31.23 |
1358 |
||||
1.000 |
47.20 |
2052 |
||||
Overall Average: |
37.19 |
1617 |
||||
Gartenacker |
0.010 |
48.80 |
1877 |
27.10 |
1042 |
0.91 |
0.250 |
21.35 |
821 |
||||
0.500 |
26.65 |
1025 |
||||
0.750 |
25.75 |
991 |
||||
1.000 |
46.85 |
1802 |
||||
Overall Average: |
33.88 |
1303 |
||||
Table 12.Summary of Kd,des, KOC, KF, KFOC and 1/n Values from the Desorption Step
Soil |
Nominal Rate Applied Aqueous Phase (µg/mL) |
Partition Coefficients |
Freundlich Coefficients |
|||
Kd,des |
KOC des |
KF des |
KFOC des |
1/n |
||
North Dakota |
0.010 |
610.00 |
24400 |
127.09 |
5083 |
0.78 |
0.250 |
255.44 |
10218 |
||||
0.500 |
221.48 |
8859 |
||||
0.750 |
213.52 |
8541 |
||||
1.000 |
205.13 |
8205 |
||||
Overall Average: |
301.11 |
12045 |
||||
White Swan |
0.010 |
106.50 |
6265 |
89.62 |
5272 |
0.97 |
0.250 |
91.96 |
5409 |
||||
0.500 |
110.25 |
6485 |
||||
0.750 |
104.76 |
6163 |
||||
1.000 |
82.98 |
4881 |
||||
Overall Average: |
99.29 |
5841 |
||||
Marsillargues |
0.010 |
312.50 |
31250 |
148.94 |
14894 |
0.86 |
0.250 |
310.56 |
31056 |
||||
0.500 |
366.30 |
36630 |
||||
0.750 |
226.63 |
22263 |
||||
1.000 |
125.19 |
12519 |
||||
Overall Average: |
268.24 |
26744 |
||||
18 Acres |
0.010 |
138.25 |
6011 |
53.08 |
2308 |
0.89 |
0.250 |
64.40 |
2800 |
||||
0.500 |
84.33 |
3667 |
||||
0.750 |
74.27 |
3229 |
||||
1.000 |
63.50 |
2761 |
||||
Overall Average: |
84.95 |
3694 |
||||
Gartenacker |
0.010 |
214.00 |
8231 |
36.66 |
1410 |
0.77 |
0.250 |
48.27 |
1857 |
||||
0.500 |
91.41 |
3516 |
||||
0.750 |
59.45 |
2286 |
||||
1.000 |
70.98 |
2730 |
||||
Overall Average: |
96.82 |
3724 |
||||
Description of key information
Average Log Koc = 3.55 (Koc = 3521) based on four studies covering 15 soils, equilibrium batch method, OECD 106, Freguson & Atkinson 2014, Kuet 2006, Barizon 2005 and Capps 1982 (no guideline followed).
Key value for chemical safety assessment
- Koc at 20 °C:
- 3 521
Additional information
Table. Summary of the Kfoc values for the substance
USDA |
Name / Origin |
OC* |
pH |
Kf/Kd* |
Koc* |
1/n |
Author / Year |
Sandy loam |
North Dakota, USA |
2.5 |
7.8 |
74.13 |
2965 |
0.75 |
Ferguson & Atkinson / 2014 |
Silt loam |
White Swan, USA |
1.7 |
5.9 |
46.77 |
2751 |
0.91 |
Ferguson & Atkinson / 2014 |
Silty clay |
Marsillargues, FR |
1.0 |
7.8 |
45.59 |
4559 |
0.91 |
Ferguson & Atkinson / 2014 |
Sandy clay loam |
18 Acres, UK |
2.3 |
6.0 |
32.40 |
1409 |
0.94 |
Ferguson & Atkinson / 2014 |
Loam |
Gartenacker, DE |
2.6 |
7.0 |
27.10 |
1042 |
0.91 |
Ferguson & Atkinson / 2014 |
Clay loam |
Bologna, IT (0 - 50 cm horizon) |
1.04 |
7.0 |
18.4 |
1763 |
- |
Kuet / 2006
|
Silty clay loam |
Bologna, IT (50 - 90 cm horizon) |
0.58 |
7.4 |
17.0 |
2938 |
- |
Kuet / 2006
|
Clay |
Argissolo, BR |
2.1 |
5.8 |
219 |
17923 |
0.84 |
Barizon / 2005 |
Clay |
Latossolo, BR |
2.1 |
4.5 |
34 |
1638 |
0.76 |
Barizon / 2005 |
Loamy sand |
Neossolo, BR |
0.8 |
4.7 |
16 |
1953 |
0.84 |
Barizon / 2005 |
Silty clay loam |
Ohio, US |
1.86 |
6.6 |
26 |
1400 |
0.87 |
Capps / 1982 |
Silt |
Tennessee, US |
0.41 |
7.5 |
29 |
7000 |
0.95 |
Capps / 1982 |
Sand |
Florida, US |
0.35 |
n.r. |
3 |
850 |
0.96 |
Capps / 1982 |
Sandy loam |
Ohio, US |
1.86 |
n.r. |
20 |
1100 |
0.80 |
Capps / 1982 |
Arithmetic mean Koc |
|
|
|
|
3521 |
0.87 |
|
* Units: OC(%), Kf/Kd and Koc (mL/g)
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