Methanesulfonamide, N-[2-[(4,6-dimethoxy-1,3,5-triazin-2-yl)carbonyl]-6-fluorophenyl]-1,1-difluoro-N-methyl-

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

2000

Qualifier:

according to guideline

Guideline:

other: US EPA Test Guidelines, OPPTS 835.1230, Adsorption/Desorption (Batch Equilibrium), 2008

Qualifier:

according to guideline

Guideline:

other: Japanese MAFF New Test Guidelines, Part 2-9-10, 2001

Qualifier:

according to guideline

Guideline:

other: Canada PMRA, Guidelines for Registration of Pesticides, Environmental Chemistry and Fate, 1987

GLP compliance:

yes (incl. QA statement)

Remarks:

Ministerium für Arbeit, Gesundheit und Soziales des Landes Nordrhein-Westfalen

Type of method:

batch equilibrium method

Media:

soil

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
PHYSICO-CHEMICAL PROPERTIES
- Vapour pressure: 6.4 x 10-E6 Pa at 20°C
- Water solubility:
41 mg/L (distilled water, pH 6.8) at 20°C
36 mg/L (buffer, pH 4) at 20°C
33 mg/L (buffer, pH 7) at 20°C
34 mg/L (buffer, pH 9) at 20°C
- log Pow: 1.5 - 1.6
- pKa: no pKa in water at 1.1 < pH < 10.4
- Stability of test material:
pH 4: < 10% degradation after 30 days at 25°C
pH 7: < 15% degradation after 30 days at 25°C
pH 9: DT50 < 3 days at 25°C

Radiolabelling:

yes

Test temperature:

20.0°C - 20.3°C

Details on study design: HPLC method:

EQUIPMENT
- HPLC system: Agilent 1100 Series chromatography workstation with UVdetector (VWD, Agilent 1100 Series) operated at 254 nm and radioactivity detector (Ramona Star, Raytest, Straubenhardt, Germany) and MS spectrometer
- 14C Detector: Ramona Star (Raytest), equipped with a 370 μL glass solid phase scintillator flow cell
- Software: Data acquisition and HPLC control: Gina Star (Raytest)
- Column: Purospher Star RP-18e, 250 x 4.6 mm, 5 μm (Merck)
- Guard column: Purospher Star RP-18e, 4 x 4 mm, 5 μm (Merck)

MOBILE PHASES
- Type: Gradient method
- Flow rate: 1.0 mL/min
- Temp.: 40°C
- Injection volume: 10 – 500 μL
- Eluent A: 1 % formic acid in water
- Eluent B: 1 % formic acid in acetonitrile

REFERENCE SUBSTANCES
- Identity: Non-Radiolabeled AE 1887196, (1.4 mg) was dissolved in 1.4 mL of acetonitrile/water

EVALUATION
Calculation of the Freundlich constant and related KOC was performed according to OECD 106

Analytical monitoring:

yes

Details on sampling:

- Concentrations: Four different soils at five concentrations in the range of about 0.01 to 1.0 mg/L
- Sampling interval: At equilibrium (after 24 hours)
- Sample storage before analysis: The samples were analyzed immediately after preparation or directly after sampling.

Details on matrix:

COLLECTION AND STORAGE
- Geographic location:
#1: Laacher Hof AXXa, Monheim, Germany (GPS coordinates: N 51° 04.6' E 006° 53.5')
#2: Dollendorf II, Blankenheim, Germany (GPS coordinates: N 50° 22.9' E 006° 43.0')
#3: Laacher Hof Wurmwiese, Monheim, Germany (GPS coordinates: N 51° 04.9' E 006° 55.3')
#4: Hoefchen Am Hohenseh 4a, Burscheid, Germany (GPS coordinates: N 51° 04.0' E 007° 06.3')
- Storage conditions: Refrigerated at ≤ 8°C for < 2 months
- Soil preparation: Sieved to ≤ 2 mm, air dried

PROPERTIES
#1: Laacher Hof AXXa
- Soil texture: Sandy Loam
- % sand: 75
- % silt: 19
- % clay: 6
- Soil taxonomic classification: Sandy, mixed, mesic, Typic Cambudolls
- Soil classification system: USDA
- pH: 6.4
- Organic carbon (%): 2.1
- CEC (meq/100 g): 9.6
- Water Holding Capacity 0.33 bar (%): 12
- Bulk density (g/cm3): 1.21

#2: Dollendorf II
- Soil texture: Loam
- % sand: 35
- % silt: 41
- % clay: 24
- pH: 7.2
- Organic carbon (%): 4.7
- CEC (meq/100 g): 21.2
- Water Holding Capacity 0.33 bar (%): 32.5
- Bulk density (g/cm3): 0.96

#3: Laacher Hof Wurmwiese
- Soil texture: Sandy Loam
- % sand: 55
- % silt: 29
- % clay: 16
- Soil taxonomic classification: Loamy, mixed, mesic, Typic Argudalfs
- Soil classification system: USDA
- pH: 5.5
- Organic carbon (%): 2.0
- CEC (meq/100 g): 10.7
- Water Holding Capacity 0.33 bar (%): 16.9
- Bulk density (g/cm3): 1.15

#4: Hoefchen Am Hohenseh 4a
- Soil texture: Silt Loam
- % sand: 25
- % silt: 61
- % clay: 14
- Soil taxonomic classification: Loamy, mixed, mesic, Typic Argudalfs
- Soil classification system: USDA
- pH: 6.6
- Organic carbon (%): 2.3
- CEC (meq/100 g): 14.5
- Water Holding Capacity 0.33 bar (%):
- Bulk density (g/cm3): 1.06

Details on test conditions:

TEST SYSTEM
- Type, size and further details on reaction vessel: Centrifuge tubes with screw cap, material Teflon®, volume 42 mL
- Agitation: Test vessels were shaken by an mechanical overhead shaker, 30 ± 2 rpm
- Temperature: 20 ± 2°C, walk-in climatic chamber, recorded by a Thermistor connected to a data logger (Squirrel 1200, Grant Inst. Ltd).
- Equilibration time: 24 hours (adsorption), 24 hours (desorption)
- Method of preparation of test solution: 5g (#1, #3, #4) or 2g (#2) soil was weighed into the centrifuge tubes and aqueous 0.01 M CaCl2 solution
containing 50 mg/L HgCl2 was added to a water volume of 18 mL (corrected for soil moisture). After pre-equilibration by shaking overnight, 2 mL of the respective application solution was added to a final volume of 20 mL.
- Number of reaction vessels/concentration: Duplicates with five concentrations for each soil (0.01, 0.03, 0.10, 0.29, and 1.14 mg/L)
- Desorption test: The supernatants were decanted, weighed and replaced by a corresponding volume of aqueous 0.01 M CaCl2 solution containing 50 mg/L HgCl2.

Duration:

24 h

Initial conc. measured:

0.01 - 1.14 other: mg/L

Temp.:

20 °C

Duration:

24 h

Temp.:

20 °C

Computational methods:

- Adsorption and desorption coefficients (Kd): Calculations according to OECD Guideline 106.
- Freundlich adsorption and desorption coefficients: Calculations according to OECD Guideline 106.
- Slope of Freundlich adsorption/desorption isotherms: Calculations according to OECD Guideline 106.
- Adsorption coefficient per organic carbon (Koc): Based on the Freundlich Kf value the respective Freundlich Koc value was determined.

Type:

Koc

Value:

101.9

Temp.:

20 °C

Remarks on result:

other: soil #1

Type:

Koc

Value:

100.3

Temp.:

20 °C

Remarks on result:

other: soil #2

Type:

Koc

Value:

85.8

Temp.:

20 °C

Remarks on result:

other: soil #3

Type:

Koc

Value:

104.9

Temp.:

20 °C

Remarks on result:

other: soil #4

Adsorption and desorption constants:

The adsorption constants KF(ads) of AE 1887196 for the four test soils calculated based on the Freundlich isotherms ranged from 1.715 to 4.712 mL/g (mean: 2.745 mL/g).
The desorption constants KF(des) of AE 1887196 were approx. 2 times higher than the respective adsorption constants indicating a stronger binding of the test item once adsorbed to the soils.

Recovery of test material:

The test item was stable in the course of the study. The parental mass balance for the adsorption/desorption phase was > 94 % of the applied radioactivity. No major degradation product was observed.

Details on results (Batch equilibrium method):

No significant correlation between pH and adsorption can be seen for the Koc of the investigated soils.

 Table 1: Summary of adsorption in soil

	KF[mL/g]	l/n	R2	KOC [mL/g]
Soil #1	2.140	0.9292	0.9971	101.9
Soil #2	4.712	0.9081	0.9993	100.3
Soil #3	1.715	0.9197	0.9996	85.8
Soil #4	2.412	0.9247	0.9989	104.9
Mean	2.745	0.9204	0.9987	98.2

 

Table 2: Summary of desorption in soil

	KF[mL/g]	l/n	R2	KOC [mL/g]
Soil #1	4.677	0.9687	0.9984	222.7
Soil #2	9.788	0.9422	0.9995	208.3
Soil #3	3.740	0.9485	0.9991	187.0
Soil #4	4.535	0.9334	0.9990	197.2
Mean	5.685	0.9482	0.9990	203.8

 

Description of key information

logKoc = 1.9-2.0 (OECD 106)

Triafamone has a low adsorption potential to soil and sediment.

Additional information

The adsorption / desorption of triafamone (CAS No. 874195-61-6) was studied in four soils in batch equilibrium experiments according to OECD guideline 106 under GLP conditions (Eckermann and Koenig, 2012). The studies were conducted in the dark in the laboratory with test concentrations of 0.01, 0.03, 0.10, 0.29 and 1.14 mg/L for 48 hours at 20.1 °C. The four representative soils are sampled from agricultural use areas and cover a wide range of physico-chemical properties. Radio labeled [phenyl-UL-14C] triafamone was used as test substance and the amounts of test item and its degradation products were determined by liquid scintillation counting (LSC). The complete material balances found in the test demonstrated that there was no significant loss of radioactivity from the test systems or during sample processing. The adsorption parameters were calculated using the Freundlich adsorption isotherm. The resulting Koc values for the adsorption of triafamone ranged for the four soils between 85.8 and 104.9 (logKoc =1.9-2.0).