Reaction mass of 3-(difluoromethyl)-1-methyl-N-[(1RS,4SR,9RS)-1,2,3,4-tetrahydro-9-isopropyl-1,4-methanonaphthalen-5-yl]pyrazole-4-carboxamide and of 3-(difluoromethyl)-1-methyl-N-[(1RS,4SR,9SR)-1,2,3,4-tetrahydro-9-isopropyl-1,4-methanonaphthalen-5-yl]pyrazole-4-carboxamide; isopyrazam

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption, other

Remarks:

batch equilibrium method

Type of information:

experimental study

Adequacy of study:

key study

Study period:

9 Aug 2005 to 28 Feb 2006

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:

no

Qualifier:

according to guideline

Guideline:

other: EPA 163-1

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Canada PMRA guideline T-I-255

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:

Definitive test
- Initial queous concentration: 0.005, 0.02, 0.05, 0.2 and 0.5 µg/mL
- Adsorption sampling: After the equilibration time had elapsed, the tubes were removed from the shaker and centrifuged at 3500 r.p.m. for 15 minutes on a centrifuge to separate the soil and aqueous phases. The supernatants were transferred to labelled glass vials and volume recorded.
- Desoprtion samling: After the equilibration time had elapsed, the samples were then centrifuged in the same way as adsorption sampling. The supernatants were transferred to labelled glass vials and volume recorded.

Matrix no.:

#1

Matrix type:

sandy clay loam

% Clay:

23

% Silt:

22

% Sand:

55

% Org. carbon:

2.55

pH:

5.4

CEC:

16.9 meq/100 g soil d.w.

Matrix no.:

#2

Matrix type:

sandy loam

% Clay:

13

% Silt:

27

% Sand:

60

% Org. carbon:

0.46

pH:

6

CEC:

9.9 meq/100 g soil d.w.

Matrix no.:

#3

Matrix type:

sand

% Clay:

4

% Silt:

7

% Sand:

89

% Org. carbon:

0.29

pH:

7

CEC:

3.5 meq/100 g soil d.w.

Matrix no.:

#4

Matrix type:

loam

% Clay:

16

% Silt:

48

% Sand:

36

% Org. carbon:

2.03

pH:

7.1

CEC:

8.4 meq/100 g soil d.w.

Matrix no.:

#5

Matrix type:

silty clay

% Clay:

44

% Silt:

48

% Sand:

8

% Org. carbon:

2.38

pH:

7.2

CEC:

29.7 meq/100 g soil d.w.

Matrix no.:

#6

Matrix type:

silty clay loam

% Clay:

35

% Silt:

59

% Sand:

6

% Org. carbon:

1.04

pH:

7.7

CEC:

6.2 meq/100 g soil d.w.

Details on matrix:

Detailed information on tested soils is provided in Table 1 in 'Any other information on materials and methods, incl. tables'.
COLLECTION AND STORAGE
- Geographic location:
Soil I: 18 Acres - Jealott's Hill Farm, Nupton Road, Warfield, Bracknell, UK
Soil II: Visalia - Syngenta Western Regional Technical Centre, 498 North Mariposa Road, Visalia, CA 93292, USA.
Soil III: Washington - Qualls Agricultural Laboratory, Grant County, Washington
Soil IV: Gartenacker - Syngenta Crop Protection AG, Les Barges/VS, Switzerland
Soil V: Champaign High - Syngenta Crop Protection, Northern Regional Technical Centre, 495 County Road 1300N, Champaign, Illinois 61822, USA
Soil VI: Marsillargues - Syngenta Agro SAS, La Paluzette, F-34490 Marsillargues, France.
- Sampling depth (cm):
Soil I: 5 - 20 cm
Soil II: 0 - 15 cm
Soil III: 0 - 15 cm
Soil IV: 0 - 20 cm
Soil V: From 0.5 - 1 cm to 12.5 - 15.0 cm
Soil VI: Maximum depth 10 cm
- Soil preparation: After sampling, the soils were air dried and passed through a sieve (2 mm mesh).
- Storage conditions: The soils were stored at ca 4°C until required.

Details on test conditions:

TEST CONDITIONS
- Buffer: Aqueous CaCl2 (0.01M) solution
TEST SYSTEM
- Test vessel: 50 mL Teflon tubes
- Amount of soil / aqueous phase per treatment: 1 g of soil: 20 mL aqueous CaCl2 for 18 Acres and Champaign High soils and 2 g of soil: 20 mL aqueous CaCl2 for Visalia, Washington, Gartenacker and Marsillargues soils
- Number of reaction vessels/concentration: 2 replicate samples per application rate
- Preparation of soil slurries prior to treatment: Prior to treatment with 14C-labelled test substance, soil samples were equilibrated at least overnight in Teflon tubes with aqueous CaCl2 (0.01 M). Each tube contained 1 or 2 g dry weight equivalent soil and sufficient 0.01 M CaCl2 to bring the final volume in the tube to 20 mL. Equilibration of the untreated soil slurries was by continuous mixing on an end-over-end shaker at approximately 22 revolutions per minute (r.p.m.) 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 ofthe slurries.
- Preparation of application solutions: The 14C-labelled test item was dissolved in acetonitrile. Four application solutions with different radioactive concentrations were prepared in acetonitrile in order to achieve initial aqueous phase solution concentrations of 0.005, 0.02, 0.05, 0.2 and 0.5 µg/mL, The same application solution was used for concentrations 0.02 and 0.05 µg/mL. These solutions were quantified by LSC and the volume required for preparation of each application solution determined.
- Application of 14C-Iabelled test substance to slurries: Aliquots (< 100 µL) of the 14C-Iabelled test substance application solutions were applied to the pre-equilibrated soil:aqueous slurries. Aliquots of each application solution were quantified by LSC (pre-and post-application), to check the homogeneity of the treatment solutions and to deternline the exact application rate. HPLC analysis of some of the pre- and all post-application checks was undertaken to determine the purity of the test substance.

Duration:

23 h

Initial conc. measured:

0.005 other: µg/mL

Temp.:

20 °C

Duration:

23 h

Initial conc. measured:

0.02 other: µg/mL

Temp.:

20 °C

Duration:

23 h

Initial conc. measured:

0.05 other: µg/mL

Temp.:

20 °C

Duration:

23 h

Initial conc. measured:

0.2 other: µg/mL

Temp.:

20 °C

Duration:

23 h

Initial conc. measured:

0.5 other: µg/mL

Temp.:

20 °C

Duration:

18.5 h

Temp.:

20 °C

Key result

Sample No.:

#1

Type:

Koc

Remarks:

Freundlich Coefficient

Value:

2 031 L/kg

pH:

5.4

Temp.:

20 °C

Matrix:

sandy clay loam

% Org. carbon:

2.55

Key result

Sample No.:

#2

Type:

Koc

Remarks:

Freundlich Coefficient

Value:

2 491 L/kg

pH:

6

Temp.:

20 °C

Matrix:

sandy loam

% Org. carbon:

0.46

Key result

Sample No.:

#3

Type:

Koc

Remarks:

Freundlich Coefficient

Value:

4 122 L/kg

pH:

7

Temp.:

20 °C

Matrix:

sand

% Org. carbon:

0.29

Key result

Sample No.:

#4

Type:

Koc

Remarks:

Freundlich Coefficient

Value:

1 732 L/kg

pH:

7.1

Temp.:

20 °C

Matrix:

loam

% Org. carbon:

2.03

Key result

Sample No.:

#5

Type:

Koc

Remarks:

Freundlich Coefficient

Value:

2 109 L/kg

pH:

7.2

Temp.:

20 °C

Matrix:

silty clay

% Org. carbon:

2.37

Key result

Sample No.:

#6

Type:

Koc

Remarks:

Freundlich Coefficient

Value:

2 009 L/kg

pH:

7.7

Temp.:

20 °C

Matrix:

silty clay loam

% Org. carbon:

1.04

Sample No.:

#1

Phase system:

solids-water in soil

Type:

other: Koc

Remarks:

Desorption Freundlich Coefficient

Value:

2 678 L/kg

Temp.:

20 °C

pH:

5.4

Matrix:

sandy clay loam

% Org. carbon:

2.55

Sample No.:

#2

Phase system:

solids-water in soil

Type:

other: Koc

Remarks:

Desorption Freundlich Coefficient

Value:

3 901 L/kg

Temp.:

20 °C

pH:

6

Matrix:

sandy loam

% Org. carbon:

0.46

Sample No.:

#3

Phase system:

solids-water in soil

Type:

other: Koc

Remarks:

Desorption Freundlich Coefficient

Value:

6 241 L/kg

Temp.:

20 °C

pH:

7

Matrix:

sand

% Org. carbon:

0.29

Sample No.:

#4

Phase system:

solids-water in soil

Type:

other: Koc

Remarks:

Desorption Freundlich Coefficient

Value:

1 946 L/kg

Temp.:

20 °C

pH:

7.1

Matrix:

loam

% Org. carbon:

2.03

Sample No.:

#5

Phase system:

solids-water in soil

Type:

other: Koc

Remarks:

Desorption Freundlich Coefficient

Value:

2 674 L/kg

Temp.:

20 °C

pH:

7.2

Matrix:

silty clay

% Org. carbon:

2.37

Sample No.:

#6

Phase system:

solids-water in soil

Type:

other: Koc

Remarks:

Desorption Freundlich Coefficient

Value:

2 706 L/kg

Temp.:

20 °C

pH:

7.7

Matrix:

silty clay loam

% Org. carbon:

1.04

Adsorption and desorption constants:

See Table 4 - Table 5 in 'Any other information on results incl. tables'
The average Kd values and corresponding KOC values for the adsorption step were 73.35 and 2874 L/kg for 18 Acres, 14.20 and 3060 L/kg for Visalia, 13.31 and 4588 L/kg for Washington, 43.62 and 2149 L/kg for Gartenacker, 68.91 and 2898 L/kg for Champaign High and 28.87 and 2766 L/kg for Marsillargues soil. The KF values were 51.83 L/kg for 18 Acres, 11.56 L/kg for Visalia, 11.95 L/kg for Washington, 35.17 L/kg for Gartenacker, 50.16 L/kg for Champaign High and 20.97 L/kg for Marsillargues. The corresponding KFOC values were 2031, 2491, 4122, 1732, 2109 and 2009 L/kg respectively.
For the desorption step, the average Kd values were 96.63 (18 Acres), 19.64 (Visalia), 18.21 (Washington), 54.51 (Gartenacker), 88.86 (Champaign High) and 37.82 L/kg (Marsillargues). The corresponding desorption KOC values were 3786, 4233, 6280, 2685, 3736 and 3623 mL/g (OC) respectively. The KF values were 68.34, 18.10, 18.10, 39.51, 63.59 and 28.25 L/kg for 18 Acres, Visalia, Washington, Gartenacker, Champaign High and Marsillargues respectively. The corresponding desorption KFOC values were 2678, 3901, 6241, 1946, 2674 and 2706 L/kg, respectively. The increase in the Kd, KOC, KF and KFOC between the adsorption and desorption steps suggested that the adsorption of 14C-labelled test item is not fully reversible in these soils.

Recovery of test material:

See Table 9 - Table 10 in 'Any other information on results incl. tables'
The mass balance was determined on selected samples from the highest treatment concentration (0.5 µg/mL) in the definitive test. The mass balances ranged from 94.0 to 96.7 % of the applied radioactivity. These results were considered acceptable for the calculation of the radioactive soil concentrations within the test system.

Sample no.:

#1

Duration:

23 h

% Adsorption:

>= 74.7 - <= 81.5

Sample no.:

#2

Duration:

23 h

% Adsorption:

>= 54.4 - <= 63.6

Sample no.:

#3

Duration:

23 h

% Adsorption:

>= 52.4 - <= 60

Sample no.:

#4

Duration:

23 h

% Adsorption:

>= 78.5 - <= 83

Sample no.:

#5

Duration:

23 h

% Adsorption:

>= 73.7 - <= 80.9

Sample no.:

#6

Duration:

23 h

% Adsorption:

>= 69.9 - <= 77.7

Duration:

18.5 h

Remarks on result:

other:

Remarks:

not specifiec

Transformation products:

not specified

Details on results (Batch equilibrium method):

See Table 3 - Table 13 in 'Any other information on results incl. tables'
- Stability of test item: The stability of test item in the soil; aqueous slurries was investigated as part of the definitive phase by chromatographic analysis of the aqueous supernatants and soil extracts from selected samples from the highest concentration range (0.5 µg/mL). Chromatographic analysis was conducted on the aqueous supernatant from the adsorption and desorption stages and soil extract. Due to the low levels of radioactivity in each sample, analysis was only performed on single samples from the highest treatment rate (0.5 µg/mL concentration) for each soil type. The results showed a single peak with a similar retention time to test item, concluding that test item is stable throughout the definitive phase of this study.
- Syn and anti isomer ratios: The syn and anti isomer ratios were determined by HPLC in 18 Acres and Washington soil extracts, adsorption and desorption supernatants at the 0.5 µg/mL concentration. There did not appear to be any significant difference between the syn and anti isomer ratios in any of the three sample extracts for either soils analysed within experimental error. The results show that the syn and anti isomers do not show different adsorption or desorption properties to each other. The mean syn and anti isomer ratios were 90.8% syn and 9.2% anti for 18 Acres soil and 91.0 % and 9.0 % for Washington soil. This result demonstrated that the ratios remained the same throughout the study.
- Adsorption of 14C-labelled test item to soil: The initial concentrations of test item were calculated for each soil by the distribution of radioactivity. The Freundlich equations showed a good fit to the data with r2 values of 1.0. The corresponding 1/n values ranged from 0.92 to 0.97. The highest 1/n value was observed in Washington soil and lowest in 18 Acres soil. Using the McCall Classification scale to assess the chemical's potential mobility in soil (based on its KFOC), 14C-labelled test item can be classified as having a "low" potential mobility in Gartenacker and a "slight" potential mobility in 18 Acres,Visalia, Washington, Champaign High and Marsillargues soils.
- Desorption of 14C-labelled test item from soil: Average Kd values after the desorption step were found to be 96.63 for 18 Acres, 19.64 for Visalia, 18.21 for Washington, 54.51 Gartenacker, 88.86 Champaign High and 37.82 mL/g for Marsillargues soils, with corresponding average Koc values of 3786,4233, 6280, 2685, 3736 and 3623 mL/g (OC) respectively. The Freundlich equation showed a good fit to the desorption data in all soils with r2 values of 1.00 for the desorption step. The Freundlich coefficients (Kf) calculated for the first desorption step were found to be 68.34, 18.10, 18.10,39.51, 63.59 and 28.25, with corresponding KFOC values of 2678, 3901, 6241, 1946,2674 and 2706 for 18 Acres, Visalia, Washington, Gartenacker, Champaign High and Marsillargues soils respectively. The Kd, Koc, KF and KFOC values after the desorption step were all increasingly higher than those after the adsorption step for all soils. These data therefore suggest that adsorption of 14C-labelled test item is not fully reversible.

Table 3. Concentrations of the test item equivalents (based on distribution of radioactivity)

Soil	Treatment Concentration (µg/mL)	Aqueous Phase Concentration (µg/mL) (a)	Soil Phase Concentration (µg/g) (a)	Percentage of Applied test item equivalents Adsorbed
18 Acres 1:20 Soil:Aqueous Ratio	0.5	0.1265	7.4762	74.7
		0.1219	7.5698	75.6
	0.2	0.0489	3.0220	75.6
		0.0460	3.0786	77.0
	0.05	0.0107	0.7943	78.8
		0.0106	0.7959	79.0
	0.02	0.0040	0.3279	80.5
		0.0041	0.3250	79.8
	0.005	0.0010	0.0821	80.7
		0.0009	0.0829	81.5
Visalia 1:10 Soil:Aqueous Ratio	0.5	0.2172	2.8312	56.6
		0.2280	2.7240	54.4
	0.2	0.0881	1.1182	55.9
		0.0888	1.1119	55.6
	0.05	0.0207	0.2967	58.9
		0.0204	0.3003	59.6
	0.02	0.0076	0.1275	62.6
		0.0080	0.1234	60.6
	0.005	0.0018	0.0316	63.6
		0.0022	0.0282	56.7
Washington 1:10 Soil:Aqueous Ratio	0.5	0.2380	2.6237	52.4
		0.2158	2.8454	56.9
	0.2	0.0875	1.1243	56.2
		0.0898	1.1017	55.1
	0.05	0.0207	0.2968	58.9
		0.0214	0.2901	57.6
	0.02	0.0081	0.1222	60.0
		0.0083	0.1204	59.1
	0.005	0.0021	0.0302	59.4
		0.0023	0.0274	53.9
Gartenacker 1:10 Soil:Aqueous Ratio	0.5	0.1025	3.9786	79.5
		0.1073	3.9300	78.5
	0.2	0.0390	1.6093	80.5
		0.0384	1.6161	80.8
	0.05	0.0094	0.4100	81.4
		0.0090	0.4135	82.1
	0.02	0.0036	0.1677	82.4
		0.0036	0.1679	82.5
	0.005	0.0008	0.0413	83.0
		0.0009	0.0408	82.0
Champaign High 1:20 Soil:Aqueous Ratio	0.5	0.1317	7.3737	73.7
		0.1251	7.5049	75.0
	0.2	0.0493	3.0139	75.4
		0.0493	3.0134	75.3
	0.05	0.0109	0.7900	78.4
		0.0110	0.7868	78.1
	0.02	0.0045	0.3175	78.0
		0.0044	0.3192	78.4
	0.005	0.0010	0.0811	79.8
		0.0010	0.0822	80.9
Marsillargues 1:10 Soil:Aqueous Ratio	0.5	0.1508	3.4957	69.9
		0.1453	3.5505	71.0
	0.2	0.0560	1.4400	72.0
		0.0557	1.4424	72.1
	0.05	0.0127	0.3767	74.8
		0.0126	0.3779	75.0
	0.02	0.0050	0.1531	75.2
		0.0049	0.1548	76.0
	0.005	0.0011	0.0387	77.7
		0.0012	0.0382	76.7

(a) Based on distribution of radioactivity.

 

Table 4. Summary of Kd, Koc, KF, KFoc And 1/n values from the adsorption step

Soil	Nominal Rate Applied Aqueous Phase (µg/mL)	Partition Coefficient
		Kd	Koc	KF	Krnc	1/n
18 Acres	0.5	60.60	2374	51.83	2031	0.92
	0.2	64.37	2522
	0.05	74.81	2931
	0.02	80.88	3169
	0.005	86.09	3373
	Average Values:	73.35	2874
Visalia	0.5	12.49	2692	11.56	2491	0.95
	0.2	12.61	2717
	0.05	14.54	3134
	0.02	16.07	3464
	0.005	15.29	3295
	Average Values:	14.2	3060
Washington	0.5	12.11	4174	11.95	4122	0.97
	0.2	12.56	4330
	0.05	13.96	4812
	0.02	14.74	5082
	0.005	13.17	4540
	Average Values:	13.31	4588
Gartenacker	0.5	37.72	1858	35.17	1732	0.95
	0.2	41.69	2053
	0.05	44.73	2203
	0.02	46.92	2311
	0.005	47.05	2318
	Average Values:	43.62	2149
Champaign High	0.5	58.00	2439	50.16	2109	0.93
	0.2	61.16	2572
	0.05	71.92	3024
	0.02	71.69	3014
	0.005	81.80	3439
	Average Values:	68.91	2898
Marsiliargues	0.5	23.81	2280	20.97	2009	0.93
	0.2	25.81	2472
	0.05	29.81	2856
	0.02	31.03	2972
	0.005	33.91	3247
	Average Values:	28.87	2766

 

Table 5. Summary of Kd, Koc, KF, Kfoc And 1/n Values From The desorption step

Soil	Nominal Rate Applied Aqueous Phase (µg/mL)	Partition Coefficient
		Kd	Koc	Kf	KFOc	1/n
18 Acres	0.5	78.52	3076	68.34	2678	0.93
	0.2	91.58	3588
	0.05	97.30	3812
	0.02	103.45	4054
	0.005	112.25	4399
	Average Values:	96.63	3786
Visalia	0.5	18.52	3991	18.10	3901	0.98
	0.2	18.77	4045
	0.05	20.16	4343
	0.02	21.17	4562
	0.005	19.60	4224
	Average Values:	19.64	4233
Washington	0.5	18.08	6235	18.10	6241	1.00
	0.2	17.83	6148
	0.05	19.29	6650
	0.02	17.59	6066
	0.005	18.27	6300
	Average Values:	18.21	6280
Gartenacker	0.5	45.16	2225	39.51	1946	0.94
	0.2	50.69	2497
	0.05	57.62	2838
	0.02	56.27	2771
	0.005	62.79	3093
	Average Values:	54.51	2685
Champaign High	0.5	77.15	3244	63.59	2674	0.93
	0.2	77.70	3267
	0.05	89.69	3771
	0.02	95.78	4028
	0.005	103.96	4371
	Average Values:	88.86	3736
Marsillargues	0.5	33.48	3206	28.25	2706	0.94
	0.2	33.89	3246
	0.05	38.47	3685
	0.02	38.78	3714
	0.005	44.51	4263
	Average Values:	37.82	2766

 

Table 6. Mass balance in the definitive experiment

Soil Name	% of Applied Radioactivity in:				Total
	Soil Extract	Adsorption Supernatant	Desorption Supernatant	Soil Pellet
18 Acres	57.4	2.3.8	14.8	0.7	96.7
Visalia	34.1	40.6	19.1	0.8	94.6
Washington	29.5	44.7	19.4	0.4	94.0
Gartenacker	63.1	18.6	13.3	1.5	96.5
Champaign High	54.8	24.8	15.0	1.2	95.8
Marsillargues	51.6	27.9	15.4	0.9	95.8

(a) Extractions were conducted on single samples, for each soil, which had been treated at the highest treatment concentration (0.5 µg/mL)

 

Table 7. HPLC analysis of samples from the definitive experiment

0.5µg/mLTreatment Rate - Aqueous Supematants from Adsorption and Desorption Steps

Soil	Mean% test item (a) in		Mean
	Adsorption Supernatant	Desorption Supernatant
18 Acres	100	100	100
Visalia	100	100	100
Washington	100	100	100
Gartenacker	100	100	100
Champaign High	100	100	100
Marsil \argues	100	100	100

(a) As measured by the HPLC software, according to its predefined integration algorithm.

0.5 µg/mL Treatment Rate -Acetonitrile/Water Extract from Soil Pellet (Post Desorption Step)

Soil	% test item (a) in		Mean
	Injection 1	Injection 2
18 Acres	100	100	100
Visalia	100	100	100
Washington	100	100	100
Gartenacker	100	100	100
Champaign High	100	100	100
Marsi llargues	100	100	100

(a) As measured by the HPLC software, according to its predefined integration algorithm.

 

Table 8. Syn And Anti Isomer Ratio HPLC Results From Selected 0.5 µg/mL Sample Extracts

Soil	Sample	Syn isomer	Anti isomer	Mean Syn and Anti Ratio
18 Acres	Soil Extract	89.7	10.3	90.8 syn: 9.2 anti
	Adsorption Supernatant	92.4	7.6
	Desorption Supernatant	89.7	10.3
Washington	Soil Extract	90.1	9.9	91.0 syn: 9.0 anti
	Adsorption Supernatant	92.7	7.3
	Desorption Supernatant	90.1	10.0

 

Table 9. Investigation into the suitability of the test vessel

Incubation Time (Hours)	Replicate	Bq Applied	Bq Recovered	Recovery of Applied Activity(%)
24 (Teflon)	A	66005	43140.1	65.4
	B		46130.1	69.9
48 (Teflon)	A	66005	49008.6	74.2
	B		48129.1	72.9
24 (Glass)	A	65234	56134.2	86.1
	B		55646.0	85.3

 

Table 10. Investigation into the suitability of the test vessel in the presence of soil

Sample	Replicate	Bq Recovered in Aqueous Supernatant	Bq Recovered in Soil Extract	Bq Recovered in Tube Rinse	Recovery of Applied Activity(%)
18 Acres (Teflon)	A (Methanol)	6.8	88.2	1.2	96.2
	B (2M NaOH)	6.7	86.0	0.5	93.2
18 Acres (Glass)	A (Methanol)	6.4	85.6	0.6	92.7
	B (2M NaOH)	6.5	86.1	0.3	92.9
Marsillargues (Teflon)	A (Methanol)	15.7	76.9	3.6	96.3
	B (2M NaOH)	16.0	78.1	1.4	95.5
Marsillargues (Glass)	A (Methanol)	13.4	71.7	0.5	85.6 (a)
	B (2M NaOH)	14.8	78.8	0.3	93.9

(a) The low recovery is assumed to be due to leakage from the glass vessel during adsorption.

 

Table 11. Soil:Aqueous Ratio Results From The Soil:Aqueous Preliminary Experiment

Soil Type	Soil:Aqueous Ratio	Concentration in Aqueous Phase (µg/mL) (a)	Concentration on Soil (µg/mL) (a)	Kd (a)	KOC (a)	% of Applied test item Adsorbed to Soil (a)
18 Acres	1:2	0.0205	1.0303	50.39	1974	96
	1:5	0.0450	2.4531	54.52	2136	92
	1:10	0.0777	4.5790	58.93	2309	85
	1:20	0.1338	8.1589	60.99	2390	75
Visalia	1:2	0.0979	0.8754	8.94	1927	82
	1:5	0.1773	1.7915	10.11	2179	67
	1:10	0.2383	2.9731	12.51	2696	56
Washington	1:2	0.0970	0.8773	9.08	3132	82
	1:5	0.1801	1.7775	9.87	3404	66
	1:10	0.2526	2.8305	11.22	3870	53
Gartenacker	1:2	0.0319	1.0073	31.54	1553	94
	1:5	0.0663	2.3464	35.38	1743	88
	1:10	0.1158	4.1982	36.26	1786	78
	1:20	0.1914	7.0064	36.61	1803	65
Champaign High	1:2	0.0216	1.0280	47.52	1998	96
	1:5	0.0448	2.4540	54.79	2304	92
	1:10	0.0833	4.5233	54.31	2284	84
	1:20	0.1349	8.1354	60.29	2535	75
Marsillargues	1:2	0.0438	0.9837	22.47	2152	92
	1:5	0.0984	2.1859	22.21	2127	82
	1:10	0.1599	3.7575	23.52	2252	70
	1:20	0.2248	6.3383	28.26	2706	59

(a) Based on distribution of radioactivity.

 

Table 12 Adsorption Of 14C -labelled test item during the preliminary adsorption experiment

Soil Type	Soil:Aqueous Ratio	Time (Hours)	Concentration in Aqueous Phase (µg/mL) (a)	Concentration on Soil (µg/g) (a)	Kd (a)	Koc (a)	% of Applied test item Adsorbed to Soil (a)
18 Acres	1:20	1	0.1738	7.4116	42.65	1651	68
		3	0.1581	7.7263	48.90	1916	71
		6	0.1517	7.8545	51.79	2029	72
		24	0.1455	7.9772	55.31	2167	73
		48	0.1245	8.3985	67.48	2644	77
Visalia	1:10	1	0.2958	2.4856	8.41	1812	46
		3	0.2755	2.6887	9.76	2103	49
		6	0.2620	2.8237	10.78	2323	52
		24	0.2462	2.9820	12.12	2613	55
		48	0.2130	3.3135	15.55	3352	61
Washington	1:10	1	0.2797	2.6467	9.46	3262	49
		3	0.2715	2.7290	10.06	3469	50
		6	0.2665	2.7787	10.43	3595	51
		24	0.2365	3.0793	13.02	4490	57
		48	0.2359	3.0851	13.08	4510	57
Gaetenacker	1:10	1	0.1363	4.0814	29.96	1476	75
		3	0.1325	4.1194	31.10	1532	76
		6	0.1247	4.1971	33.68	1659	77
		24	0.1126	4.3182	38.47	1895	79
		48	0.1167	4.2769	36.69	1807	79
Champaign High	1:20	1	0.1611	7.6764	47.64	2003	71
		3	0.1577	7.7444	49.10	2065	71
		6	0.1503	7.8917	52.50	2208	72
		24	0.1384	8.1298	58.77	2471	75
		48	0.1299	8.2999	63.92	2688	76
Marsillargues	1:10	1	0.1964	3.4803	17.72	1698	64
		3	0.1854	3.5904	19.38	1856	66
		6	0.1757	3.6871	20.99	2010	68
		24	0.1604	3.8395	23.93	2292	71
		48	0.1513	3.9314	25.99	2490	72

(a) Based on distribution of radioactivity.

 

Table 13 Desorption of 14C -labelled test item during the preliminary desorption experiment

Soil	Soil: Aqueous Ratio	Mean Kd from24 Hour Adsorption Step (al	Time (Hours)	Concentration on Soil After Adsorption Step (µg/g) (a)	Concentration on Soil After Desorption Step (µg/g) (a)	Kd (a)	Koc (a)	% of Applied Radioactivity Desorbed from Soil (a)
18 Acres	1:20	63.76	1	8.4307	6.8499	79.03	3097	19
			3	8.3746	6.7231	74.41	2915	20
			6	8.3114	6.6702	74.06	2902	20
			24	8.3030	6.6718	74.48	2918	20
Visalia	1:10	11.95	1	2.9821	2.0419	18.51	3989	32
			3	2.9932	1.9918	17.13	3691	33
			6	3.0048	1.9833	16.76	3613	34
			24	2.9733	1.9739	16.97	3658	34
Washington	1:10	11.72	1	2.9775	2.0529	19.10	6586	31
			3	2.9320	1.9289	16.71	5763	34
			6	2.9731	1.9941	17.66	6088	33
			24	2.9605	1.9547	16.89	5823	34
Gartenacker	:10	36.61	1	4.3116	3.6085	44.29	2182	16
			3	4.3088	3.5888	43.13	2124	17
			6	4.3346	3.6290	44.53	2193	16
			24	4.2900	3.5800	43.45	2140	17
Champaign High	1:20	54.64	1	8.0852	6.5105	74.65	3139	19
			3	8.0171	6.3141	67.28	2829	21
			6	8.0155	6.3365	68.38	2875	21
			24	8.0562	6.4316	71.60	3011	20
Marsillargues	1:10	23.00	1	3.8323	3.0487	33.59	3217	20
			3	3.8192	2.9919	31.42	3009	22
			6	3.8332	3.0026	31.45	3012	22
			24	3.8186	2.9628	30.23	2896	22

(a) Based on distribution of radioactivity.

Validity criteria fulfilled:

yes

Conclusions:

In an OECD TG 106, EPA 163.1 and Canada PMRA T-1-255 guidelines followed adsorption/desorption study, the Freundlich coefficients (KFOC) were calculated to be 2031, 2491, 4122, 1732, 2109 and 2009 L/kg for 18 Acres (sandy clay), Visalia (sandy loan), Washington (sand), Gartenacker (loam), Champaign High (silty clay) and Marsillargues (silty clay loam) soils, respectively.

Executive summary:

The adsorption and desorption properties of pyrazole-14C-labelled-test item were studied in six soils: 18 Acres (sandy clay loam), Visalia (sandy loam), Washington (sand), Gartenacker (loam), Champaign High (silty clay) and Marsillargues (silty clay loam). The study was performed according to OECD TG 106, EPA 163-1 and Canada PMRA T-1 -255 guidelines, and in compliance with GLP criteria. The soil: aqueous ratios and the time for reaching adsorption and desorption equilibrium were determined in preliminary experiments. The definitive experiment was carried out at 20 ± 2°C using all six soils with a 23-hour adsorption phase and an 18.5-hour desorption phase. The final soil: aqueous ratios were 1 g of soil: 20 mL aqueous CaCl2 (1:20) for 18 Acres and Champaign High soils, and 2 g of soil : 20 mL aqueous (1:10) CaCl2 for Visalia, Washington, Gartenacker and Marsillargues soils. The 14C-labelled test substance was added to the soil: aqueous slurries to achieve five nominal rates of application (0.005, 0.02, 0.05, 0.2 and 0.5 µg/mL). The radiochemical purity of the treatment solutions as well as syn- and anti- isomer ratios in the soil extract, adsorption and desorption supernatants was determined by HPLC analysis. The amounts of radioactivity contained in solutions were measured using LSC.

The mass balance was determined on selected samples from the highest treatment concentration (0.5 µg/mL) in the definitive test. The mass balances ranged from 94.0 to 96.7 % of the applied radioactivity. These results were acceptable to justify the calculation of the radioactive soil concentrations within the test system. Freundlich coefficients (KFOC) were calculated to be 2031, 2491, 4122, 1732, 2109 and 2009 L/kg for 18 Acres (sandy clay), Visalia (sandy loan), Washington (sand), Gartenacker (loam), Champaign High (silty clay) and Marsillargues (silty clay loam) soils, respectively. Using the McCall Classification scale to assess a chemical's potential mobility in soil (based on its KFOC), both the syn- and anti- isomers of test item can be classified as having a "low" potential mobility in Gartenacker soil and a "slight" potential mobility in 18 Acres, Visalia, Washington, Champaign High and Marsillargues soils.

Reference 2

Endpoint:

adsorption / desorption, other

Remarks:

batch equilibrium method

Type of information:

experimental study

Adequacy of study:

key study

Study period:

5 Mar 2008 to 21 Jul 2009

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:

updated 21 January 2000

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:

Preliminary/screening test and advance test
- Sample intervals: In the preliminary/screening test the adsorption kinetics was followed for all soils after four time intervals: 2, 5, 24 and 48 hours of adsorption (shaking). For three intervals (2, 5 and 24 hours) one soil-to-solution ratio was used whereas for time interval 48 hours, three different soil-to-solution ratios were used. After 2, 5, 24 and 48 hours of desorption (shaking), duplicate tubes were sampled.
- Test concentration: 0.31 mg/L (Preliminary/screening test); 0.005, 0.01, 0.05, 0.1 and 0.30 mg/L (advanced test)

Matrix no.:

#1

Matrix type:

clay loam

% Clay:

33.95

% Silt:

24.94

% Sand:

41.11

% Org. carbon:

2.6

pH:

5.89

CEC:

29.4 meq/100 g soil d.w.

Matrix no.:

#2

Matrix type:

clay

% Clay:

61.86

% Silt:

18.7

% Sand:

19.44

% Org. carbon:

1.86

pH:

3.98

CEC:

21.14 meq/100 g soil d.w.

Matrix no.:

#3

Matrix type:

loamy sand

% Clay:

11.8

% Silt:

4.13

% Sand:

84.07

% Org. carbon:

0.65

pH:

4.64

CEC:

9.16 meq/100 g soil d.w.

Matrix no.:

#4

Matrix type:

clay loam

% Clay:

37.12

% Silt:

39.8

% Sand:

23.08

% Org. carbon:

9.72

pH:

3.58

CEC:

58.15 meq/100 g soil d.w.

Details on matrix:

Sampling locations and characteristics of the soil are provided in Table 1 in 'Any other information on materials and methods incl. tables'.
COLLECTION AND STORAGE
- Geographic location:
Soil I: Piracicaba / RS- Brazil, 22°40’ S, 47°37’ W
Soil II: Veranópolis / RS- Brazil, 28°53’ S, 51°33’ W
Soil III: Osório / RS- Brazil, 29°53’ S, 50°16’ W
Soil IV: Viamão / RS- Brazil, 30°04’ S, 50°51’ W
- Collection procedures: Collection of the soils was performed based on ISO guideline 10381-6.
- Pesticide history: None of the soils had been fertilised for at least 6 month (organic), 3 month (anorganic), or treated with pesticides for at least 12 months prior to sampling.
- Sampling depth (cm): Soils II to IV were sampled from their top 20 cm soil layers in November 2007 and soil I in April 2008.
- Storage conditions: The soils were stored at about +4°C until use.
- Soil preparation: Soils were sieved to 2 mm after sampling and arrived in good condition at the test facility. Disaggregation was performed with minimal force, so that the original texture of the soil was not changed. Thereafter, the soils were homogenised and the moisture content determined by heating triplicate aliquots in an infrared drier. The air-dried soil samples were equilibrated by shaking with 0.01M CaCl2 solution in tarred test tubes over the weekend before the start of the experiment. The soil samples were equilibrated with about 90% of the final volume of the aqueous phase.

Details on test conditions:

TEST SYSTEM
- Type and further details on reaction vessel: Sealed glass centrifuge tubes which minimised adsorption of the test item on their surfaces.
- Amount of soil: 1 or 3 g
- Soil/water ratio: In the preliminary test, the adsorption behaviour of 14C-labelled test item was tested using three different soil (dry weight) to aqueous phase ratios (3/25, 1/50 and 1/100 for soil I; 1/25, 3/25 and 1/50 for soils II and III and 1/25, 1/50 and 1/100 for soil IV).
In the Advanced test, the soil/solution ratios of 1/25 (soils II and III), 1/50 (soil I) and 1/100 (soil IV) were used and the agitation time was 48 hours in order to determine the adsorption/desorption isotherms.
- Number of reaction vessels/concentration: 2
- Method of preparation of test solution: Soil samples were shaken each with 25, 50 or 100 mL 0.01 M CaCl2 solution, at the test concentration of 0.313 mg/L. The tubes were shaken in the dark at 160 rpm sufficient to keep the soil in homogeneous suspension.

Duration:

48 h

Initial conc. measured:

0.31 other: mg/L

Temp.:

20 °C

Remarks:

Preliminary test; applicable for all soils

Duration:

48 h

Initial conc. measured:

>= 0.005 - <= 0.3 other: mg/L

Temp.:

20 °C

Remarks:

Advanced test; applicable for all soils

Duration:

48 h

Temp.:

20 °C

Key result

Sample No.:

#1

Type:

Koc

Remarks:

Freundlich Coefficient

Value:

1 785 L/kg

pH:

5.89

Temp.:

20 °C

Matrix:

clay loam

% Org. carbon:

2.6

Key result

Sample No.:

#2

Type:

Koc

Remarks:

Freundlich Coefficient

Value:

2 227 L/kg

pH:

3.98

Temp.:

20 °C

Matrix:

clay

% Org. carbon:

1.86

Key result

Sample No.:

#3

Type:

Koc

Remarks:

Freundlich Coefficient

Value:

3 861 L/kg

pH:

4.46

Temp.:

20 °C

Matrix:

loamy sand

% Org. carbon:

0.65

Key result

Sample No.:

#4

Type:

Koc

Remarks:

Freundlich Coefficient

Value:

2 585 L/kg

pH:

3.58

Temp.:

20 °C

Matrix:

clay loam

% Org. carbon:

9.72

Sample No.:

#1

Phase system:

solids-water in soil

Type:

other: Koc - Desorption Freundlich Coefficient

Value:

2 851 L/kg

Temp.:

20 °C

pH:

5.89

Matrix:

clay loam

% Org. carbon:

2.6

Sample No.:

#2

Phase system:

solids-water in soil

Type:

other: Koc - Desorption Freundlich Coefficient

Value:

2 936 L/kg

Temp.:

20 °C

pH:

3.98

Matrix:

clay

% Org. carbon:

1.86

Sample No.:

#3

Phase system:

solids-water in soil

Type:

other: Koc - Desorption Freundlich Coefficient

Value:

5 685 L/kg

Temp.:

20 °C

pH:

4.64

Matrix:

loamy sand

% Org. carbon:

0.65

Sample No.:

#4

Phase system:

solids-water in soil

Type:

other: Koc - Desorption Freundlich Coefficient

Value:

11 615 L/kg

Temp.:

20 °C

pH:

3.58

Matrix:

clay loam

% Org. carbon:

9.72

Adsorption and desorption constants:

An overview of the results is provided in Table 12 in "Any other information on results incl. tables"
Advanced test
- Adsorption: The results obtained were evaluated by applying the linear Freundlich equation. The resulting constants KF and KFOC are ranging between 41.419 - 251.277 and 1785 - 3861 respectively. The coefficients of determination (r2) for the linear regression of the linear form of the Freundlich equation were not lower than 0.9968. The 1/n values 0.99 for soils II and III show almost linearity involved in the adsorption process. In soils I and IV the values range from 0.87 to 0.90 indicating some concentration dependency of the adsorption behaviour. Radioactivity in the control samples was entirely recovered and was constant for all concentrations. The KFOC, ads values of soils II, III, and IV classify the test item as slightly mobile according to McCall. The KFOC, ads value of soil I characterised the test item as low mobile. According to the classification of Guth, the test item can be classified as immobile in the soils tested.
- Desorption: The (linear and nonlinear) isotherms were established from the values obtained after 48 hours of desorption. The resulting constants KF, des, 1/n and KFOC, des are ranging between 36.954 - 1129.025, 0.88 - 1.02, 2851 - 11615 respectively. The calculated KFOC, des values were higher than those obtained for the adsorption isotherms, indicating that a partially irreversible adsorption occurs in soil. The correlation coefficients (r2) for the linear regression of the linear form of the Freundlich equation were not lower than 0.9950. The 1/n values of the desorption step were close to 1.0 for soil II, III, and IV. For soil I, the 1/n value is similar to that for the adsorption isotherm.

Recovery of test material:

An overview of the results is provided in Table 6 in "Any other information on results incl. tables"
- Preliminary/screening test: The mass balance was performed for soils II and III at the soil to aqueous phase ratio of 1/25 and 1/100 for soil I and at 1/50 for soil IV at a test item concentration of 0.31 mg/L. The recovery of the radioactivity was 107.4%, 90.1%, 91.1% and 94.0% for soils I, II, III and IV, respectively. In the supernatant, amounts of 69.3%, 33.0%, 45.0% and 12.5% of the applied radioactivity were detected. Extractions with acetonitrile/water (4/1; v/v) recovered 36.9%, 56.0%, 45.8% and 79.5% for soils I, II, III and IV, respectively. Only 1.2%, 1.1%, 0.3% and 2.0% of the radioactivity applied remained non-extracted. Analysis of the extractables by TLC showed only the test item.

Sample no.:

#1

Duration:

48 h

% Adsorption:

>= 53.6 - <= 69.1

Remarks on result:

other: Measured in all concentrations

Remarks:

Advanced

Sample no.:

#2

Duration:

48 h

% Adsorption:

>= 61.5 - <= 65.4

Remarks on result:

other: Measured in all concentrations

Remarks:

Advanced

Sample no.:

#3

Duration:

48 h

% Adsorption:

>= 49.7 - <= 54.1

Remarks on result:

other: Measured in all concentrations

Remarks:

Advanced

Sample no.:

#4

Duration:

48 h

% Adsorption:

>= 75.9 - <= 83.8

Remarks on result:

other: Measured in all concentrations

Remarks:

Advanced

Sample no.:

#1

Duration:

48 h

% Desorption:

>= 36.2 - <= 55

Remarks on result:

other: Measured in all concentrations

Remarks:

Advanced

Sample no.:

#2

Duration:

48 h

% Desorption:

>= 41.1 - <= 47.6

Remarks on result:

other: Measured in all concentrations

Remarks:

Advanced

Sample no.:

#3

Duration:

48 h

% Desorption:

>= 27.7 - <= 32.9

Remarks on result:

other: Measured in all concentrations

Remarks:

Advanced

Sample no.:

#4

Duration:

48 h

% Desorption:

>= 67.7 - <= 77

Remarks on result:

other: Measured in all concentrations

Remarks:

Advanced

Transformation products:

no

Details on results (Batch equilibrium method):

An overview of the results is provided in Table 2 – Table 14 in 'Any other information on results incl. tables'.
- Radiochemical purity and stability of the test item: The purity of 14C-labelled test item was tested by HPLC at treatment of the test solutions and by TLC in the incubated samples. 14C-labelled test item was determined to be stable, showing a purity of 100% at application and between 95.57% and 99.03% in the incubated sample after 48 hours of adsorption.
- Preliminary/screening test: All values reported here represent the mean of duplicate samples. The preliminary/screening test was performed using four soil types, soil I (Piracicaba, clay loam), soil II (Veranópolis, clay), soil III (Osório, loamy sand) and soil IV (Viamão, clay loam) and three different soil to solution ratios: 1/25, 3/25 and 1/50 or 1/100 at a test item concentration of 0.31 mg/L each. Adsorption kinetics was followed after 2, 5, 24 and 48 hours of shaking. Equilibrium of adsorption was reached within 24 to 48 hours of shaking. Consequently, an equilibration period of 48 hours was selected for the advanced test. The percentages of the applied amount adsorbed after 48 hours for soil I were 28.3%, 47.6% and 85.7% at the ratios 1/100, 1/50 and 3/25, respectively. The values for soil II were 53.2%, 66.7% and 85.1% at the ratios 1/50, 1/25 and 3/25 and for soil III, 47.3%, 60.9% and 80.1% at the same ratios. For soil IV the values were 63.7%, 86.6% and 96.6% at the ratios 1/100, 1/50 and 1/25. Therefore a soil-to-solution ratio of 1/25 for soils II and III, 1/50 for soil I and 1/100 for soil IV were used for the advanced test. No significant adsorption on the surface of the test vials was found in the control samples. A maximum amount of 6.4% was adsorbed after 48 hours.
The desorption kinetics was followed after 2, 5, 24 and 48 hours of shaking. The desorption equilibrium was reached after about 24 hours for all soils. Nevertheless, a desorption period of 48 hours was selected for the advanced test. For soil I, the amount desorbed after 48 hours accounted for 13.0% of the amounts applied. The corresponding values were 15.2% for soil II, 19.6% for soil III, and 3.6% for soil IV. The test item was stable in the supernatants during the adsorption and desorption steps. TLC analysis of the supernatants after 48 hours of adsorption/desorption confirmed the stability under the test conditions.

Statistics:

Not reported.

Table 2. Preliminary/Screening Test: Radioactivity Adsorbed to Soils I (Piracicaba) and II (Veranópolis), Using Three Different Soil to Solution Ratios at an Initial Concentration of 0.31 mg/L (Values are given in percent of applied radioactivity)

Soil I (clay loam) % of applied	Adsorption time (hours)
	2	5	24	48
1/100
Sample A	11.5	20.3	23.0	25.4
Sample B	11.1	14.0	25.0	31.1
Mean	11.3	17.1	24.0	28.3
1/50
Sample A	n.p.	n.p.	n.p.	50.6
Sample B	n.p.	n.p.	n.p.	44.6
Mean	n.p.	n.p.	n.p.	47.6
3/25
Sample A	n.p..	n.p.	n.p.	87.1
Sample B	n.p..	n.p.	n.p.	84.3
Mean	n.p..	n.p.	n.p.	85.7

 

Soil II (clay) % of applied	Adsorption time (hours)
	2	5	24	48
1/25
Sample A	51.7	57.5	64.6	67.3
Sample B	51.7	57.2	64.1	66.1
Mean	51.7	57.4	64.4	66.7
1/50
Sample A	n.p.	n.p	n.p	54.1
Sample B	n.p	n.p	n.p	52.3
Mean	n.p.	n.p.	n.p.	53.2
3/25
Sample A	n.p.	n.p.	n.p.	85.0
Sample B	n.p.	n.p.	n.p.	85.1
Mean	n.p.	n.p.	n.p.	85.1

n.p. not performed

 

Table 3. Preliminary/Screening Test: Radioactivity Adsorbed to Soil III (Osório), Soil IV (Viamão) and Radioactivity of the Control Samples Using Three Different Soil to Solution Ratios at an Initial Concentration of 0.31 mg/L

(Values are given in percent of applied radioactivity).

Soil III (loamy sand) % of applied	Adsorption time (hours)
	2	5	24	48
1/25
Sample A	37.8	52.2	58.2	58.1
Sample B	36.7	51.4	56.0	63.7
Mean	37.3	51.8	57.1	60.9
1/50
Sample A	n.p.	n.p.	n.p.	45.5
Sample B	n.p.	n.p.	n.p.	49.1
Mean	n.p.	n.p.	n.p.	47.3
3/25
Sample A	n.p.	n.p.	n.p.	81.0
Sample B	n.p.	n.p.	n.p.	79.3
Mean	n.p.	n.p.	n.p.	80.1

 

Soil IV (clay loam) % of applied	Adsorption time (hours)
	2	5	24	48
1/100
Sample A	n.p.	n.p.	n.p.	62.4
Sample B	n.p.	n.p.	n.p.	65.1
Mean	n.p.	n.p.	n.p.	63.7
1/50
Sample A	52.9	66.3	81.0	86.4
Sample B	45.0	70.7	85.6	86.7
Mean	48.9	68.5	83.3	86.6
1/25
Sample A	n.p.	n.p.	n.p.	96.6
Sample B	n.p.	n.p.	n.p.	96.6
Mean	n.p.	n.p.	n.p.	96.6

 

Control % of applied	Adsorption time (hours)
	2	5	24	48
Sample A	104.8	100.8	102.2	92.9
Sample B	100.1	103.7	101.1	94.3
Mean	102.5	102.3	101.6	93.6

n.p. not performed

 

Table 4. Results of the Preliminary/Screening Test. Distribution of 14C-test item Between Aqueous Phase and Soil After Adsorption for 48 Hours at Soil to Aqueous Phase Ratios of 1/25, 1/50 and 1/100

Sample	Ratio	m [g]	Vo [mL]	m(ads)s [µg]	m(ads)aq [µg]	Kd [mL/g]	Kd*ratio [mL/g]	Koc [mL/g]
Soil I (clay loam) Sample A Sample B	1/100	1 1	100 100	7.95 9.74	23.33 21.55	34.09 45.19	0.34 0.45	1311 1738
Mean				8.85	22.44	39.64	0.40	1525
Soil II (clay) Sample A Sample B	1/25	1 1	25 25	5.26 5.17	2.56 2.65	51.47 48.83	2.06 1.95	2767 2625
Mean				5.22	2.60	50.15	2.01	2696
Soil III (loamy sand) Sample A Sample B	1/25	1 1	25 25	4.54 4.99	3.28 2.84	34.63 43.95	1.39 1.76	5327 6762
Mean				4.76	3.06	39.29	1.57	6044
Soil IV (clay loam) Sample A Sample B	1/50	1 1	50 50	13.51 13.57	2.13 2.08	316.85 326.87	6.34 6.54	3260 3363
Mean				13.54	2.10	321.86	6.44	3311

 

m	=	Mass of soil (g)
Vo	=	Initial volume of the aqueous phase in contact with the soil (mL)
m(ads)s	=	Mass of the test item adsorbed on the soil at adsorption equilibrium (µg)
m(ads)aq	=	Mass of test item in the solution at adsorption equilibrium (µg)
Kd	=	Distribution coefficient (mL/g)

 

Table 5. Preliminary/Screening Test: Desorption Kinetics for Soils I (Piracicaba), II (Veranópolis), III (Osório) and IV (Viamão) (Values are given in percent of applied radioactivity).

Soil I (clay loam) % of applied	Desorption time (hours)
	2	5	24	48
1/100 Sample A Sample B	10.3 12.1	11.6 10.2	15.1 12.8	12.8 13.3
Mean	11.2	10.9	13.9	13.0

 

Soil II (clay) % of applied	Desorption time (hours)
	2	5	24	48
1/25
Sample A	13.8	15.4	16.6	14.9
Sample B	13.3	15.4	16.3	15.4
Mean	13.5	15.4	16.5	15.2

 

Soil III (loamy sand) % of applied	Desorption time (hours)
	2	5	24	48
1/25
Sample A	15.1	17.9	18.4	19.7
Sample B	15.9	17.8	19.5	19.4
Mean	15.5	17.8	18.9	19.6

 

Soil IV (clay loam) % of applied	Desorption time (hours)
	2	5	24	48
1/50
Sample A	3.9	3.7	4.3	3.3
Sample B	3.0	4.9	3.7	3.8
Mean	3.5	4.3	4.0	3.6

 

 

Table 6. Preliminary/Screening Test: Mass Balance in Percent of Radioactivity Applied After 48 Hours of Adsorption at an Initial Concentration of 0.31 mg/L

Sample	Ratio	mass applied [µg]	(ads)aq [%]	(ads)extract [%]	(ads)residue [%]	recovery [%]
Soil I (clay loam)
Sample A Sample B	1/100	31.3 31.3	66.4 72.2	35.7 38.2	1.3 1.1	103.3 111.5
Mean		31.3	69.3	36.9	1.2	107.4
Soil II (clay)
Sample A Sample B	1/25	7.8 7.8	32.6 33.4	56.4 55.7	1.2 0.9	90.2 90.0
Mean		7.8	33.0	56.0	1.1	90.1
Soil III (loamy sand)
Sample A Sample B	1/25	7.8 7.8	45.1 44.9	46.0 45.6	0.3 0.4	91.4 90.8
Mean		7.8	45.0	45.8	0.3	91.1
Soil IV (clay loam)
Sample A Sample B	1/50	15.6 15.6	11.9 13.1	79.6 79.5	2.0 1.9	93.5 94.5
Mean		15.6	12.5	79.5	2.0	94.0

(ads)aq: Percent of the amount applied remaining in the total aqueous phase (including soil pore water) (ads)extract: Percent of the amount applied extracted by acetonitrile/water (4:1; v/v) (without soil pore water) (ads)residue: Percent of the amount applied remaining in the soil determined by combustion

 

 

Table 7. Advanced Test: Distribution of 14C-test otem Between Aqueous Phase and Soil I After 48 Hours of Adsorption (Top) and Desorption (Bottom). Soil to Solution Ratio: 1/50, Evaluation According to the Linear Freundlich Isotherms

	Soil I (clay loam)
Concentration Ci (mg/L)	0.304	0.103	0.049	0.010	0.005
c(ads)aq (mg/L)
Sample A	0.141	0.042	0.019	0.003	0.002
Sample B	0.141	0.042	0.019	0.003	0.002
Mean (mg/L)	0.141	0.042	0.019	0.003	0.002
m(ads)s (µg)
Sample A	8.15	3.04	1.48	0.35	0.16
Sample B	8.14	3.04	1.50	0.35	0.17
Mean (µg)	8.15	3.04	1.49	0.35	0.17
Mean (% of applied)	53.6	59.2	60.9	69.1	65.4
m(ads)s / m(soil) (µg/g)	8.146	3.045	1.492	0.352	0.169
log(m(ads)s / m(soil))	0.911	0.484	0.174	-0.454	-0.773
c(ads)aq (mg/L)	0.141	0.042	0.019	0.003	0.002
log(c(ads)aq)	-0.851	-1.376	-1.718	-2.502	-2.749

 

	Soil I (clay loam)
Concentration Ci (mg/L)	0.304	0.103	0.049	0.010	0.005
c(des)aq (mg/L)
Sample A	0.058	0.018	0.008	0.001	0.001
Sample B	0.053	0.017	0.008	0.002	0.001
Mean (mg/L)	0.056	0.018	0.008	0.002	0.001
m(des)s (µg)
Sample A	5.381	2.185	1.090	0.284	0.128
Sample B	5.623	2.243	1.092	0.276	0.122
Mean (µg)	5.502	2.214	1.091	0.280	0.125
Mean (% of applied)	36.2	43.0	44.5	55.0	48.5
m(des)s / m(soil) (µg/g)	5.502	2.214	1.091	0.280	0.125
log(m(des)s / m(soil))	0.741	0.345	0.038	-0.553	-0.903
c(des)aq (mg/L)	0.056	0.018	0.008	0.002	0.001
log(c(des)aq)	-1.254	-1.754	-2.078	-2.818	-3.081

Ci = Initial concentration in the supernatant before adsorption m(ads)s = Mass of the test item adsorbed on the soil at adsorption

equilibrium (µg)

m (soil) = Mass of soil (1 g dry soil)

C(ads)aq = Concentration of test item in the solution at adsorption equilibrium (µg)

 

 

Table 8. Advanced Test: Distribution of 14C-test item Between Aqueous Phase and Soil II After 48 Hours of Adsorption (Top) and Desorption (Bottom). Soil to Solution Ratio: 1/25, Evaluation According to the Linear Freundlich Isotherms

	Soil II (Clay)
Concentration Ci (mg/L)	0.304	0.103	0.049	0.010	0.005
c(ads)aq (mg/L)
Sample A	0.115	0.037	0.019	0.003	0.002
Sample B	0.116	0.038	0.018	0.004	0.002
Mean (mg/L)	0.115	0.037	0.018	0.004	0.002
m(ads)s (µg)
Sample A	4.74	1.65	0.76	0.17	0.08
Sample B	4.71	1.62	0.77	0.17	0.08
Mean (µg)	4.72	1.64	0.77	0.17	0.08
Mean (% of applied)	62.1	63.7	62.4	65.4	61.5
m(ads)s / m(soil) (µg/g)	4.722	1.638	0.765	0.166	0.079
log(m(ads)s / m(soil))	0.674	0.214	-0.116	-0.779	-1.101
c(ads)aq (mg/L)	0.115	0.037	0.018	0.004	0.002
log(c(ads)aq)	-0.939	-1.427	-1.735	-2.454	-2.703

 

	Soil II (Clay)
Concentration Ci (mg/L)	0.304	0.103	0.049	0.010	0.005
c(des)aq (mg/L)
Sample A	0.063	0.021	0.011	0.002	0.001
Sample B	0.063	0.021	0.011	0.002	0.001
Mean (mg/L)	0.063	0.021	0.011	0.002	0.001
m(des)s (µg)
Sample A	3.304	1.170	0.514	0.121	0.053
Sample B	3.309	1.171	0.515	0.121	0.053
Mean (µg)	3.307	1.171	0.515	0.121	0.053
Mean (% of applied)	43.5	45.5	42.0	47.6	41.1
m(des)s / m(soil) (µg/g)	3.307	1.171	0.515	0.121	0.053
log(m(des)s / m(soil))	0.519	0.068	-0.288	-0.917	-1.276
c(des)aq (mg/L)	0.063	0.021	0.011	0.002	0.001
log(c(des)aq)	-1.199	-1.675	-1.975	-2.689	-2.942

Ci = Initial concentration in the supernatant before adsorption

m(ads)s = Mass of the test item adsorbed on the soil at adsorption equilibrium (µg) m (soil) = Mass of soil (1 g dry soil)

C(ads)aq = Concentration of test item in the solution at adsorption equilibrium (µg)

 

 

Table 9. Advanced Test: Distribution of 14C-test item Between Aqueous Phase and Soil III After 48 Hours of Adsorption (Top) and Desorption (Bottom). Soil to Solution Ratio: 1/25, Evaluation According to the Linear Freundlich Isotherms

 

	Soil III (loamy sand)
Concentration Ci (mg/L)	0.304	0.103	0.049	0.010	0.005
c(ads)aq (mg/L)
Sample A	0.149	0.048	0.025	0.005	0.003
Sample B	0.156	0.050	0.023	0.005	0.003
Mean (mg/L)	0.153	0.049	0.024	0.005	0.003
m(ads)s (µg)
Sample A	3.87	1.38	0.61	0.14	0.07
Sample B	3.69	1.33	0.64	0.14	0.06
Mean (µg)	3.78	1.35	0.63	0.14	0.06
Mean (% of applied)	49.7	52.5	51.2	54.1	50.4
m(ads)s / m(soil) (µg/g)	3.780	1.351	0.627	0.138	0.065
log(m(ads)s / m(soil))	0.577	0.131	-0.203	-0.862	-1.188
c(ads)aq (mg/L)	0.153	0.049	0.024	0.005	0.003
log(c(ads)aq)	-0.816	-1.311	-1.621	-2.330	-2.593

 

	Soil III (loamy sand)
Concentration Ci (mg/L)	0.304	0.103	0.049	0.010	0.005
c(des)aq (mg/L)
Sample A	0.068	0.022	0.012	0.002	0.001
Sample B	0.068	0.022	0.011	0.002	0.001
Mean (mg/L)	0.068	0.022	0.011	0.002	0.001
m(des)s (µg)
Sample A	2.259	0.843	0.338	0.084	0.036
Sample B	2.268	0.844	0.340	0.084	0.036
Mean (µg)	2.264	0.843	0.339	0.084	0.036
Mean (% of applied)	29.8	32.8	27.7	32.9	27.7
m(des)s / m(soil) (µg/g)	2.264	0.843	0.339	0.084	0.036
log(m(des)s / m(soil))	0.355	-0.074	-0.470	-1.077	-1.447
c(des)aq (mg/L)	0.068	0.022	0.011	0.002	0.001
log(c(des)aq)	-1.167	-1.650	-1.941	-2.642	-2.900

 

Ci	=	Initial concentration in the supernatant before adsorption
m(ads)s	=	Mass of the test item adsorbed on the soil at adsorption
		equilibrium (µg)
m (soil)	=	Mass of soil (1 g dry soil)
C(ads)aq	=	Concentration of test item in the solution at adsorption
		equilibrium (µg)

 

 

Table 10. Advanced Test: Distribution of 14C-test item Between Aqueous Phase and Soil IV After 48 Hours of Adsorption (Top) and Desorption (Bottom). Soil to Solution Ratio: 1/100, Evaluation According to the Linear Freundlich Isotherms

 

	Soil IV (clay loam)
Concentration Ci (mg/L)	0.304	0.103	0.049	0.010	0.005
c(ads)aq (mg/L)
Sample A	0.079	0.019	0.010	0.002	0.001
Sample B	0.067	0.021	0.011	0.002	0.001
Mean (mg/L)	0.073	0.020	0.010	0.002	0.001
m(ads)s (µg)
Sample A	22.46	8.37	3.91	0.85	0.43
Sample B	23.70	8.19	3.85	0.86	0.43
Mean (µg)	23.08	8.28	3.88	0.85	0.43
Mean (% of applied)	75.9	80.5	79.2	83.8	83.1
m(ads)s / m(soil) (µg/g)	23.082	8.282	3.880	0.853	0.428
log(m(ads)s / m(soil))	1.363	0.918	0.589	-0.069	-0.369
c(ads)aq (mg/L)	0.073	0.020	0.010	0.002	0.001
log(c(ads)aq)	-1.136	-1.697	-1.991	-2.783	-3.060

 

	Soil IV (clay loam)
Concentration Ci (mg/L)	0.304	0.103	0.049	0.010	0.005
c(des)aq (mg/L)
Sample A	0.021	0.006	0.003	0.001	0.0004
Sample B	0.019	0.006	0.003	0.001	0.0003
Mean (mg/L)	0.020	0.006	0.003	0.001	0.0004
m(des)s (µg)
Sample A	20.476	7.811	3.600	0.784	0.391
Sample B	20.680	7.803	3.625	0.784	0.393
Mean (µg)	20.578	7.807	3.613	0.784	0.392
Mean (% of applied)	67.7	75.8	73.7	77.0	76.1
m(des)s / m(soil) (µg/g)	20.578	7.807	3.613	0.784	0.392
log(m(des)s / m(soil))	1.313	0.892	0.558	-0.106	-0.407
c(des)aq (mg/L)	0.020	0.006	0.003	0.001	0.000
log(c(des)aq)	-1.700	-2.221	-2.506	-3.174	-3.442

Ci = Initial concentration in the supernatant before adsorption

m(ads)s = Mass of the test item adsorbed on the soil at adsorption equilibrium (µg) m (soil) = Mass of soil (1 g dry soil)

C(ads)aq = Concentration of test item in the solution at adsorption equilibrium (µg)

 

 

Table 11. Advanced Test: Radioactivity Recovered in the Control Solutions (not Containing any Soil) After 48 Hours of Shaking

 

	Controls
Concentration Ci (mg/L)	0.304	0.103	0.049	0.010	0.005
m(ads)aq (%)
Sample A	94.3	90.1	94.2	95.5	105.1
Sample B	94.7	94.8	100.4	94.3	106.4
Mean	94.5	92.4	97.3	94.9	105.7

 

Table12. Advanced Test: Freundlich Parameters After Adsorption (Top) and Desorption (Bottom) of 14C-test item for Soils I to III (Soil to Solution Ratio: 1/25) and Soil IV (Soil to Solution Ratio: 1/100)

 

 

Parameter	Soil I (Clay loam)	Soil II (Clay)	Soil III (loamy sand)	Soil IV (clay loam)
log(KF)	1.667	1.617	1.400	2.400
KF, ads	46.403	41.419	25.096	251.277
KFOC, ads	1785	2227	3861	2585
KFOM, ads	1035	1292	2239	1500
1/n	0.87	0.99	0.99	0.90
r2	0.9968	0.9984	0.9985	0.9981

 

Parameter	Soil I (Clay loam)	Soil II (Clay)	Soil III (loamy sand)	Soil IV (clay loam)
log(KF)	1.8700	1.7372	1.5677	3.053
KF, des	74.128	54.606	36.954	1129.025
KFOC, des	2851	2936	5685	11615
KFOM, des	1654	1703	3298	6738
1/n	0.88	1.01	1.02	1.00
r2	0.9954	0.9967	0.9950	0.9971

 

KF = Freundlich adsorption constant

KFOC = Freundlich adsorption constant related to soil organic carbon content KFOM = Freundlich adsorption constant related to soil organic matter content 1/n = Freundlich exponent

r2 = Coefficient of determination SD = Standard deviation

 

Table 13. pH Values Measured in the Aqueous Phase of Samples Without Soil and After Equilibration With Soil

 

Sample	CaCl2 0.01M	Soil I	Soil II	Soil III	Soil IV
Ratio	5.4	1:50	1:25	1:25	1:100
pH		6.1	4.3	5.8	4.0

 

Table 14. Adsorption Classes According to J.A. Guth (Top) and P.J. McCall (Bottom)

 

J. A. Guth

Range				Adsorption	Class	Mobility
Pow	RMF	Koc	Kom (Q- value)
> 10000	< 0.15	> 1725	> 1000	very strong	I	immobile
< 10000	> 0.15	< 1725	< 1000	strong	II	little mobile
> 500	< 0.8	> 172	>100
< 500	> 0.8	<172	< 100	moderate	III	moderately mobile
> 150	< 1.3	> 86	> 50
< 150	> 1.3	< 86	< 50	slight	IV	Considerably (slightly) mobile
> 50	< 2.5	> 34	> 20
< 50	> 2.5	< 34	< 20	low	V	mobile
> 20	< 5	> 17	> 10
< 20	> 5	< 17	< 10	very low	VI	very mobile

 

P.J. McCall

Koc	Mobility Class
0 - 50	very high
50 - 150	high
150 - 500	medium
500 -2000	low
2000 - 5000	slight
> 5000	immobile

Pow = Octanol-Water Partition Coefficient

Koc = Adsorption constant related to µg active ingredient (a.i.) adsorbed to 1 g organic carbon at equilibrium concentration Ce = 1 µg a.i./mL

KOM = Adsorption constant related to µg active ingredient (a.i.) adsorbed to 1 g organic matter at equilibrium concentration Ce = 1 µg a.i./mL

Koc = 1.724 · KOM;

Koc = KF · 100 / %-OC; KF: Freundlich adsorption constant

RMF = Relative mobility factor (determined in column leaching experiments)

 

Validity criteria fulfilled:

yes

Conclusions:

In an OECD TG 106 followed adsorption/desorption study, Freundlich coefficients (KFOC) were calculated to be 1785, 2227, 3861 and 2585 L/kg in Argissolo (clay loam), Latossolo (clay), Neossolo (loamy sand) and Gleissolo (clay loam) soils, respectively.

Executive summary:

The adsorption and desorption properties of 14C-phenyl labelled test substance were studied in four Brazilian soils: Argissolo (clay loam), Latossolo (clay), Neossolo (loamy sand) and Gleissolo (clay loam). The study was performed according to OECD TG 106 and in compliance with GLP criteria. A preliminary test showed that the adsorption and desorption reached equilibrium within 24 to 48 hours of shaking for all soil to solution ratios. The percentage of the applied amount that was adsorbed after 48 hours depended on the relative amount of soil and increased with increasing soil to aqueous phase ratio. Based on the results, the soil/solution ratios of 1/50 for soil I, 1/25 for soils II and III and 1/100 for soil IV, and the agitation time of 48 hours were chosen for the advanced test. In the advanced test, the adsorption and desorption properties of the 14C-labelled test substance were determined at five concentrations (0.005, 0.01, 0.05, 0.1, and 0.3 mg/L) covering ca. two orders of magnitude in all four soils. In addition, one control sample containing the test item only in 0.01 M CaCl2 solution (without soil) was set up to check the stability of the test item in CaCl2 solution and its possible adsorption to the surface of the test vessels. The test tubes were shortly shaken by hand and then mechanically shaken at 20 ± 2 °C on a rotary shaker in a temperature-controlled roomto establish equilibration. After equilibration, the soil and aqueous layers were separated by centrifuging. The aqueous phases decanted, and the supernatants analysed by 2D-TLC. After separation of the soil from the adsorption solution, the same volume of 0.01 M CaCl2 as removed after the adsorption step, was added. Thereafter, these mixtures were agitated in the same way as for the adsorption step. After desorption, the samples were centrifuged, and the supernatants analysed by LSC and TLC.

In the preliminary test, the overall recoveries of applied radioactivity ranged from 90.1 – 107.4%. The control samples showed only negligible adsorption of the test item to the tube walls. No degradation of the test item in the aqueous phases was observed during the adsorption and desorption steps. In the advanced test, the Freundlich coefficients (KFOC) were calculated to be 1785, 2227, 3861 and 2585 L/kg in Argissolo (clay loam), Latossolo (clay), Neossolo (loamy sand) and Gleissolo (clay loam) soils, respectively.

Description of key information

Arithmetic mean Koc = 2485 L/kg based on studies covering 10 soils, equilibrium batch method, OECD TG 106, EPA guideline 163.1 and Canada PMRA guideline T-1 -255 followed, Elliott & Ricketts (6 soils), 2006 and Fahrbach, 2009 (4 soils).

Key value for chemical safety assessment

Koc at 20 °C:

2 485

Additional information

There are two studies available for this endpoint. The first study covered 6 types of soil and followed OECD TG 106, EPA 163.1 and Canada PMRA guideline T-1 -255. The second study covered 4 types of soil and followed OECD TG 106 guideline. Both studies were in compliance with GLP criteria and used the equilibrium batch method. The soil types and results are summarised in the table below.

Table. Summary of Kfoc values for the test item

USDA	Name / Origin	OC*	pH	Kf/Kd*	Koc*	1/n	Author / Year
sandy clay loam	18 Acres / GB	2.55	5.40	51.83	2031	0.92	Elliott and Ricketts / 2006
sandy loam	Visalia / US	0.46	6.00	11.56	2491	0.95	Elliott and Ricketts / 2006
sand	Washington	0.29	7.00	11.95	4122	0.97	Elliott and Ricketts / 2006
loam	Gartenacker	2.03	7.10	35.17	1732	0.95	Elliott and Ricketts / 2006
silty clay	Champaign High	2.37	7.20	50.16	2109	0.93	Elliott and Ricketts / 2006
silty clay loam	Marsillargues	1.04	7.70	20.97	2009	0.93	Elliott and Ricketts / 2006
Clay loam	Piracicaba / RS- Brazil	2.60	5.89	46	1785	0.87	Fahrbach / 2009
Clay	Veranópolis / RS- Brazil	1.86	3.98	41	2227	0.99	Fahrbach / 2009
Loamy sand	Osório / RS- Brazil	0.65	4.64	25	3861	0.99	Fahrbach / 2009
Clay loam	Viamão / RS- Brazil	9.72	3.58	251	2585 (a)	0.90	Fahrbach / 2009
Arithmetic mean Koc					2485

* Units: OC(%), Kf/Kd and Koc (mL/g)

 (a) The pH and organic carbon content are outside the range quoted in OECD TG 106. Therefore, this Koc value is considered an outlier and not used to calculate the arithmetic mean.