Ziram

Adsorption / desorption

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 Feb - 14 Oct 2014

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 (incl. QA statement)

Remarks:

Swiss federal office of public health, consumer protection directorate, notification authority form chemicals, Bern, Switzerland

Type of method:

batch equilibrium method

Media:

soil

Radiolabelling:

yes

Test temperature:

20 ± 2°C

Analytical monitoring:

yes

Remarks:

LSC and HPLC

Details on sampling:

FOR BOTH LSC and HPLC MEASUREMENTS
- Concentrations: screening test: control (without soil) and 0.1 µg/mL (nominal), advance test: control (without soil) and five concentrations of 0.110, 0.037, 0.010, 0.003 and 0.001 mg/L (nominal)
- Sampling interval:
- Screening test: after one and two hours of shaking
- Advanced test: Samples were taken after 1 h of shaking (based on results of preliminary test).
- Sample storage before analysis: no. due to degradation of test item

Matrix no.:

#1

Matrix type:

sand

% Clay:

>= 2.7 - <= 2.9

% Silt:

>= 8.6 - <= 12.4

% Sand:

>= 85.4 - <= 88

% Org. carbon:

0.66

pH:

5.2

CEC:

>= 3.5 - <= 4.7 other: mmol/100 g soil

Matrix no.:

#2

Matrix type:

clay loam

% Clay:

27

% Silt:

52

% Sand:

21

% Org. carbon:

3.85

pH:

5.64

CEC:

13.6 other: mmol/100 g soil

Matrix no.:

#3

Matrix type:

silt loam

% Clay:

15

% Silt:

84

% Sand:

2

% Org. carbon:

1.3

pH:

6.63

CEC:

13.3 other: mmol/100 g soil

Matrix no.:

#4

Matrix type:

clay

% Clay:

>= 38.6 - <= 42.8

% Silt:

>= 31.9 - <= 37.1

% Sand:

>= 21.4 - <= 28.2

% Org. carbon:

1.66

pH:

7.1

CEC:

>= 25.8 - <= 28 other: mmol/100 g soil

Matrix no.:

#5

Matrix type:

sandy loam

% Clay:

>= 10.5 - <= 12.5

% Silt:

>= 29.2 - <= 32.2

% Sand:

>= 56.4 - <= 59.2

% Org. carbon:

0.95

pH:

7.3

CEC:

>= 13.8 - <= 20.4 other: mmol/100 g soil

Details on matrix:

COLLECTION AND STORAGE
- Geographic location: Soils were collected from different agricultural areas. Sampling and handling was performed under consideration of ISO 10381-6.
- Soil 1: Speyer 2.1 (Sand) sampled in Dudenhofen, Rhineland-Palatinate, Germany
- Soil 2: RefeSol 03-G (Clay loam/Silt loam) sampled in Schmallenberg, NorthrheineWestphalia, Germany
- Soil 3 RefeSol 02-A (Silt loam) sampled in Schmallenberg, Northrheine-Westphalia, Germany
- Soil 4: Speyer 6S (Clay) sampled in Siebeldingen, Rhineland-Palatinate, Germany
- Soil 5 Speyer 5M (Sandy loam) sampled in Mechtersheim Rhineland-Palatinate, Germany
- Collection procedures: Plant cover of the soil was removed and the soil was sampled from the top soil layer.
- Sampling depth (cm): 20-30 cm
- Storage conditions: in closed container, at room temperature
- Soil preparation: Air-dried at ambient temperature and sieved through a 2-mm sieve. The soil samples were pre-equilibrated with about 90% of the targeted volume of the aqueous phase (0.01 M CaCl2) by shaking for at least over night at 20 ± 2 °C prior to application of the test item. Soil was sterilized for the screening and the advanced test.

PROPERTIES
- Moisture (in g/100 d dry soil): Soil 1: Speyer 2.1 (Sand): 0.43, Soil 2: RefeSol 03-G (Clay loam/Silt loam): 2.38, Soil 3 RefeSol 02-A (Silt loam): 1.70, Soil 4: Speyer 6S (Clay): 3.78, Soil 5 Speyer 5M (Sandy loam): 1.26

Details on test conditions:

TEST SYSTEM
- Type, size and further details on reaction vessel: sealed Teflon centrifuge tubes
- Water filtered (i.e. yes/no; type of size of filter used, if any):
- Amount of soil and water per treatment (if simulation test): see Section "any other information on material and methods incl. tables"
- Soil-solution ratio (if simulation test):
- Preliminary test: 1:2, 1:10, 1:100
- Screening test: 1:100
- Advanced test: A soil-to-solution ratio of 1:100 was used for soils II, III, IV and V (1 g/100 mL) and a ratio of 1:20 for soil I (5 g/100 mL).
- Number of reaction vessels/concentration: Two (screening and advanced test was performed using one soil per day due to the instability of [14C]Ziram).
- Test performed in open system: no
- Method of preparation of application solutions:
- Preliminary test: A stock solution was prepared by dissolving an aliquot of the radiolabeled test item in 10 mL acetone. The radioactivity content (determined by triplicate LSC measurements of 20 µL stock solution diluted in 20 mL acetone) was 117'330'000 dpm/mL, corresponding to a concentration of 379 µg [14C]Ziram/mL. An aliquot of 1.3 mL of the stock solution was diluted with 3.7 mL acetone corresponding to a radioactivity of 31'424 dpm/µL and a concentration of 102 µg [14C]Ziram/mL.
- Screening test: Soil IV: An aliquot of 270 µL of the stock solution was diluted with 730 µL acetone (radioactivity of 31'818 dpm/µL, corresp. to 103 µg [14C]Ziram/mL). Remaining soils: A stock solution was prepared by dissolving an aliquot of the test item in 3 mL acetone (radioactivity of 75'530 dpm/µL, corresp. to 225 µg [14C]Ziram/mL). An aliquot of 450 µL of the stock solution was diluted with 550 µL acetone (radioactivity content of 39'545 dpm/µL, corresp. to 118 µg [14C]Ziram/mL). Radioactivity content was always determined by triplicate LSC measurements.
- Advanced test: An aliquot of the radioactive test item was dissolved in 3 mL acetone (radioactivity content: 58'780 dpm/µL, corresp. to 175 µg [14C]Ziram/mL). The application solutions with final nominal concentrations of 0.001, 0.003, 0.01, 0.032, 0.101 µg/mL were prepared by dilutions of the stock solution in acetone. The application solutions were stored at -20 °C and used for all soils in the advanced test. The actual concentration of each application solution was re-determined by LSC measurements prior each sample preparation day.
- Are the residues from the adsorption phase used for desorption: No desorption test was performed due to the instability of the test item in the test system.
- Other: Tubes were shaken in the dark to keep the soil in homogeneous suspension.
- Control samples: test item in 0.01 M CaCl2 solution (without soil)
- Blank samples: Soil I and IV were subjected to the same test procedure as the preliminary test (soil-to-solution ratio 1:10) using the same amount of soil and the same total volume of aqueous solution (without test item). These samples served as background control during analysis to detect any contamination.

Computational methods:

- Other: All calculations were performed with Excel in Microsoft Office Professional 2010.

Sample No.:

#1

Type:

Koc

Value:

775 L/kg

pH:

5.2

Temp.:

20 °C

Matrix:

sand

% Org. carbon:

0.66

Sample No.:

#2

Type:

Koc

Value:

1 147 L/kg

pH:

5.64

Temp.:

20 °C

Matrix:

clay loam

% Org. carbon:

3.85

Sample No.:

#3

Type:

Koc

Value:

3 261 L/kg

pH:

6.63

Temp.:

20 °C

Matrix:

silt loam

% Org. carbon:

1.3

Sample No.:

#4

Type:

Koc

Value:

34 779 L/kg

pH:

7.1

Temp.:

20 °C

Matrix:

clay

% Org. carbon:

1.66

Sample No.:

#5

Type:

Koc

Value:

12 501 L/kg

pH:

7.3

Temp.:

20 °C

Matrix:

sandy loam

% Org. carbon:

0.95

Adsorption and desorption constants:

No desorption test was performed due to the instability of the test item in the test system.

Recovery of test material:

- Screening test: The recoveries ranged between 97.4% and 101.7%.

Concentration of test substance at end of adsorption equilibration period:

For results see Section "any other information on results incl. tables".

Concentration of test substance at end of desorption equilibration period:

No desorption test was performed due to the instability of the test item in the test system.

Transformation products:

not measured

Details on results (Batch equilibrium method):

PRELIMINARY TEST
- Sample purity: > 95% purity in all application solutions (HPLC). Degradation of [14C]Ziram after one hour of agitation was observed and considered for evaluation.
- Soil to solution ratios: 1:2, 1:10 and 1:100 were tested. In soil to solution ratios of 1:2 and 1:10 no test substance could be detected and therefore excluded from further testing.
- Weighed soil: 1 g
- Volume of aqueous solution: 100 mL
- Test substance concentration in final solution: 0.1 µg/mL (nominal)
- Adsorption times: 2, 6 and 24 h were tested. Short adsorption time was needed to avoid complete degradation of Ziram.
- Soil sterility: Sterile and non sterile soil were tested. The test item was not stable despite the use of sterilised soil.

MAIN TEST: PERFORMANCE
- Test material stability during adsorption phase: The results showed acceptable degradation in both phases for soils I to III. In soil extracts of soil IV (clay) and V (sandy loam), [14C]Ziram was below 40% of applied and in a few samples even not detectable. For more details see table 1 in Section "any other information on results incl. tables".
- Experimental conditions maintained throughout the study: yes
- Buffer/test substance interactions affecting sorption: no
- Further chemical interactions: no
- Buffer-catalyzed degradation of test substance: not observed
- Anomalies or problems encountered (if yes): no
- Other observations: No adsorption on test tubes observed.

RESIDUES
- Non-extractable residues (% of applied amount at end of study period): <10.7%

PRELIMINARY TEST:

For the samples of the soil-to-solution ratio of 1:100 and 2 h of adsorption time, a complete mass balance was performed. Total recovery of the radioactivity was between 97.7 and 106.8% of the applied radioactivity for sterile and non-sterile samples. It was decided to perform the screening test with all five soils, sterilised and at a soil-to-solution ratio of 1g/100 mL and adsorption times of one and two hours.

Table 1: Preliminary test – Mass balance of test item between aqueous phase and soil after 2 hours of adsorption at a soil-to-solution ratio 1:100. Mean values are given in percent of applied radioactivity (AR).

Soil	(ads)aq [%]	(ads)extract [%]	(ads)res [%]	Recovery [%]
Soil I Sand	87.8	8.3	1.6	97.7
Soil IV Clay	40.1	50.1	13.9	104.0
Soil I Sand	88.4	11.5	1.6	101.5
Soil IV Clay	34.1	59.9	12.8	106.8

(ads)aq = % of the amount applied remaining in the aqueous phase

(ads)extract = % of the amount applied extracted after adsorption

(ads)res = % of the amount applied irreversibly bound to the soil matrix

SCREENING TEST

Table 1: Screening test: % of [14C]Ziram (parent compound) in the aqueous phase (supernatant) and soil extract determined by HPLC.

Soil			% of [14C] Ziram Adsorption time (hours)
			1	2
I	Supernatant	Sample A	80.3	73.2
		Sample B	n.a.	n.a.
	Soil Extract	Sample A	86.3	85.1
		Sample B	n.a.	n.a.
II	Supernatant	Sample A	100.0	85.8
		Sample B	n.a.	n.a.
	Soil Extract	Sample A	84.7	82.8
		Sample B	n.a.	n.a.
III	Supernatant	Sample A	85.4	94.2
		Sample B	n.a.	n.a.
	Soil Extract	Sample A	90.7	56.9
		Sample B	n.a.	n.a.
IV	Supernatant	Sample A	100.0	74.4
		Sample B	100.0	55.6
	Soil Extract	Sample A	100.0	55.6
		Sample B	0.0	0.0
V	Supernatant	Sample A	100.0	82.9
		Sample B	n.a.	n.a.
	Soil Extract	Sample A	31.6	24.5
		Sample B	n.a.	n.a.

n.a.= not analysed

0.0 = not detected

Depending on the soil texture, the radioactivity recovered in the supernatant solutions, ranged between 17.7% and 93.9%. The amounts recovered in the soil extracts ranged from 6.2 % to 71.9%. The non-extracted amounts remained low, not exceeding 10.7%.

Table 2: Screening test – Mass balance of test item between aqueous phase and soil after 1 and 2 hours of adsorption at a soil-to-solution ratio 1:100. Values are given in percent of applied radioactivity (AR).

Soil	Adsorption time point	(ads)aq [%]	(ads)extract [%]	(ads)res [%]	Recovery [%]
Soil I Sand	1 h	93.9	6.2	1.6	101.7
	2 h	92.2	6.9	1.8	100.9
Soil II Clay loam	1 h	63.8	32.5	7.1	103.4
	2 h	59.3	32.9	10.1	102.3
Soil III Silt loam	1 h	64.5	31.2	3.7	99.4
	2 h	65.2	30.7	4.8	100.7
Soil IV Clay	1 h	17.7	71.0	9.3	98.1
	2 h	19.0	68.7	10.7	98.4
Soil V Sandy loam	1 h	20.4	70.1	6.8	97.4
	2 h	18.7	71.9	8.0	98.5

(ads)aq = % of the amount applied remaining in the aqueous phase

(ads)extract = % of the amount applied extracted after adsorption

(ads)res = % of the amount applied irreversibly bound to the soil matrix

Table 3: Screening test – Distribution of the test item between aqueous phase and soil after one and two hours of adsorption at a soil-to-solution ratio 1:100 including the calculated Kd and KOC values.

Soil	Adsorption time point	m [g]	V0 [mL]	m(ads)s [µg]	m(ads)aq [µg]	Kd [mL/g]	Kd*Ratio [mL/g]	KOC [mL/g]
Soil I Sand	1 h	1	100	0.57	8.03	7.1	0.07	1093
	2 h	1	100	0.62	7.19	8.6	0.09	1327
Soil II Clay loam	1 h	1	100	3.18	7.36	43.1	0.43	1121
	2 h	1	100	3.14	5.87	53.6	0.54	1392
Soil III Silt loam	1 h	1	100	3.21	6.24	51.5	0.51	3958
	2 h	1	100	1.98	6.96	28.5	0.28	2189
Soil IV Clay	1 h	1	100	n.a.	1.82	n.a.	n.a.	n.a.
	2 h	1	100	1.40	1.27	95.3	0.95	5812
Soil V Sandy loam	1 h	1	100	2.62	2.42	108.7	1.09	10865
	2 h	1	100	2.08	2.02	103.9	1.04	10389

m = Mass of soil (g)

Vo = Volume of aqueous phase (mL)

m(ads)s = Mass of test item adsorbed to soil at adsorption equilibrium (µg)

m(ads)aq = Mass of test item in aqueous phase at adsorption equilibrium (µg)

Kd = Distribution coefficient (mL/g)

Kd *Ratio = Kd*m/V0 (mL/g)

Koc = Distribution coefficient (mL/g)

ADVANCED TEST

Table 1: Advanced test: Freundlich isotherm parameters after 1 hour of adsorption.

Parameter	Soil I Sand	Soil II Clay loam	Soil III Silt loam	Soil IV Clay	Soil V Sandy loam	Mean	Standard deviation
log(KF)	0.709	1.645	1.627	2.761	2.075
KF	5.1	44.2	42.4	577.3	118.8
KFoc	775	1147	3261	34779	12501	10493	14387
KFom	449	666	1892	20173	7251	6086	8345
1/n	0.86	0.93	0.89	1.34	1.23	1.05	0.22
R²	0.973	0.961	0.979	0.980	0.949

K_F= Freundlich adsorption coefficient

K_Foc= Freundlich adsorption coefficient related to organic carbon content of soil

K_Fom= Freundlich adsorption coefficient related to organic matter content of soil

1/n = Regression constant

r₂= Regression coefficient

Table 2: Advanced test: Amount of radioactivity in the control samples. Values are given in percent of applied radioactivity.

Soil	Initial test item concentration [µg/mL]
	C1	C2	C3	C4	C5
Soil I Sand	96.7	101.5	86.6	106.0	100.0
Soil II Clay loam	99.9	-	-	-	-
Soil III Silt loam	112.1	-	-	-	-
Soil IV Clay	97.5	-	-	-	-
Soil V Sandy loam	98.7	-	-	-	-

C1-C5 = Initial test concentration as applied

Using the McCall Classification scale* to assess a chemical’s potential mobility in soil (based on its KFoc), the tested substance can be classified as having a low mobility in soil or being even immobile.

No desorption test was performed due to the instability of the test item in the test system.

*McCall P.J., Laskowski D.A., Swann R.L., and Dishburger H.J., (1981): Measurement of sorption coefficients of organic chemicals and their use in environmental fate analysis. In Test Protocols for Environmental Fate and Movement of Toxicants. Proceedings of AOAC Symposium, AOAC, Washington DC.

Reference 2

Endpoint:

adsorption / desorption: screening

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

14 June 1995 - 5 December 1995

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

other: 40 CFR 158 Environmental Fate, USEPA Pesticide Assessment Guidelines Subdivision N; Series 163-1.

Deviations:

no

GLP compliance:

yes

Type of method:

batch equilibrium method

Media:

soil

Radiolabelling:

yes

Test temperature:

25 +/- 1°C

Details on study design: HPLC method:

EQUIPMENT
- Apparatus: Shimadzu HPLC System
- Detection system: 220 nm UV; RAM 14C
- Loop: 500 uL (nominal)
- Column: Zorbax RXC8 25 x 0.46 cm
- Solvent System: A = 0.002M zinc chloride/acetonitrile (80:20 v:v)
B = acetonitrile
Gradient: Time A B
0 100 0
19 15 85
24 15 85
30 100 0
30 STOP
- Run Time: 30 Minutes
- Flow Rate: 1.5 mL/min
- Sensitivity: 0.002 Absorbance
- Chart Speed: 5 mm/min
- Temperature: Ambient, room temperature
- Approximate Retention Times: 22 minutes ziram
12 minutes CS2

- Detection limits
Soil Combustions 0.0005 ppm
Preliminary Solutions 0.0008 ppm
Adsorption Solutions 0.0008 ppm
Desorption Solutions 0.00008 ppm

Analytical monitoring:

yes

Details on sampling:

Radiocarbon analysis
- All solutions were analyzed by direct LSC in Scint-A (Packard Inst. Co.) scintillation cocktail. During the preliminary phase, duplicate 0.1 mL aliquots of each solution were removed for analysis at each sampling interval. For the definitive study, duplicate 0.1 mL aliquots of adsorption solutions and
1.0 mL of desorption solutions were analyzed
TLC analysis
- Samples of the radioactive test substance and definitive dose solutions were analyzed by one dimensional thin layer chromatography (TLC) using 10 x 20 cm glass plates pre-coated with silica gel 60 F—254 at a thickness of 0.25 mm. circled.
HPLC analysis
- Samples for the radiochemical purity check prior to definitive testing, definitive stock solutions, and one replicate per soil type of the highest concentration for the adsorption and desorption phases of the definitive study were chromatographed by HPLC

Details on matrix:

- Four types of soil (clay, sand, silt loam, sandy loam) were used in the study. Three of the four soils (clay, sand, and silt loam) were obtained by Agrisearch Incorporated and were dug from a depth of 0 to 6 inches. The California sandy loam was provided to Agrisearch Incorporated by XenoBiotic Laboratories, Inc., Plainsboro, NJ. Soils were air dried at room temperature (20 to 30°C), sieved (2 mm mesh), and stored at ambient room temperature prior to use in the study. Soils were characterized under GLPS by AGVISE Laboratories, Northwood, NO. The soil clay fraction mineralogy was obtained by AGVISE, NO from the North Dakota State University at Fargo, North Dakota

Details on test conditions:

TEST SYSTEM
- Test containers: 50 mL centrifuge tubes
- Water filtered: the drinking water was filtered, deionized, boiled, and distilled prior to use
- Amount of soil and water per treatment: 0.5 g clay soil, 18 g sand soil, 8 g silt loam soil, 8 g sandy loam soil were added to each test tube and the corresponding volume of calcium ion solution
- Number of reaction vessels/concentration: 2 per test concentration
- Method of preparation of test solution: 3.1 mg of 14C-ziram was prepared in acetone at 0.31 mg/mL. Dilutions of this stock were prepared in acetone to yield definitive dosing solutions. The final test concentrations were: 4 ug/mL, 2 ug/L, 1 ug/mL, 0.6 ug/mL, and 0.2 ug/mL

Type:

Koc

Value:

314

Remarks on result:

other: Sandy Loam

Type:

Koc

Value:

759

Remarks on result:

other: Silt Loam

Type:

Koc

Value:

1 232

Remarks on result:

other: Sand

Type:

Koc

Value:

3 732

Remarks on result:

other: Clay

Type:

log Koc

Value:

2.5

Remarks on result:

other: Sandy Loam

Type:

log Koc

Value:

2.8

Remarks on result:

other: Silt Loam

Type:

log Koc

Value:

3.1

Remarks on result:

other: Sand

Type:

log Koc

Value:

3.6

Remarks on result:

other: Clay

Adsorption and desorption constants:

Adsorption: 68.1 (clay), 2.9 (sand) , 7.6 (silt loam) and 5.7 (sandy loam)
Desorption: 450.6 (clay), 81.1 (sand), 4092.7 (silt loam) and 40.2 (sandy loam)

Observation:

However, the role of organic matter in adsorption and hence use of Koc is questionable when considering the Koc range obtained. Therefore it has to be considered also the stability of ziram.

Reference 3

Endpoint:

adsorption / desorption

Remarks:

adsorption/desorption

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

19 July 1985- 26 September 1985

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study with acceptable restrictions (only two soil types tested (sandy loam and loamy sand))

Qualifier:

according to guideline

Guideline:

other: 40 CFR 158 Environmental Fate, USEPA Pesticide Assessment Guidelines Subdivision N; Series 163-1.

GLP compliance:

yes

Type of method:

batch equilibrium method

Media:

soil

Radiolabelling:

yes

Test temperature:

25 +/- 1°C

Analytical monitoring:

yes

Details on matrix:

- Sandy loam (2) and loamy sand (2) soils were supplied by Prochimie International and ABC labs. These soils were sieved through a 10 mesh screen and autoclaved at 121°C and 15 psi. Thereafter, the soils were oven-dried at 150°C in order to remove the moisture

Details on test conditions:

- Soil samples (1 g for the Hanford loamy sand; 2 g soil for the other soils) in suspension with 10 mL [14C]ziram-treated solution (0, 0.472, 0.868, 3.94, and 7.08 μg [14C]ziram/mL 0.01 N calcium sulfate solution) were shaken during 48 hours at 25°C in the dark. For desorption the suspensions were shaken in the dark at 25°C for 72 hours with 0.01N calcium sulfate solution.

Type:

Koc

Value:

559

Remarks on result:

other: Sandy loam I

Type:

Koc

Value:

987

Remarks on result:

other: Sandy loam II

Type:

Koc

Value:

4 470

Remarks on result:

other: Loamy sand I

Type:

Koc

Value:

12 010

Remarks on result:

other: Loamy sand II

Type:

log Koc

Value:

2.7

Remarks on result:

other: Sandy loam I

Type:

log Koc

Value:

3

Remarks on result:

other: Sandy loam II

Type:

log Koc

Value:

3.6

Remarks on result:

other: Loamy sand I

Type:

log Koc

Value:

4

Remarks on result:

other: Loamy sand II

Adsorption and desorption constants:

Adsorption:
Sandy loam I: 8.0
Sandy loam II: 9.87
Loamy sand I: 13.6
Loamy sand II: 57.4
Desorption:
Sandy loam I: 22.4
Sandy loam II: 33.2
Loamy sand I: 88
Loamy sand II: 11299

Description of key information

K_Focvalues between 775 and 34779 (corresponding to log K_Focvalues of 2.89 – 4.54).

Additional information

The adsorption potential of zinc bis dimethyldithiocarbamate (CAS No. 137-30-4) was investigated in three studies.

The key study was conducted according to the OECD Guideline No. 106 and under GLP conditions (2014). A radiolabeled test substance was used for the test. The screening test was performed with 5 soils, a soil-to-solution ratio of 1g/100 mL and adsorption times of one and two hours. The advanced test (standard batch equilibrium method) was performed with five soils, five different concentrations of the test item and a soil-to-solution ratio of 1 g/100 mL for four soils and 5 g / 100 mL for one soil in order to obtain higher adsorption. The adsorption was quantified after 1 hour. The adsorption times studied were short since the test substance is unstable (investigated in preliminary test). The concentrations of the tested substance in soil extracts and aqueous phases, were analysed by HPLC. The recoveries of the radiolabeled substance in the screening test ranged from 97.4% to 103.4% (mean values). The Koc values ranged between 1093 and 11'624 mL/g depending on the soil properties. The desorption study was not performed due to the fast degradation of the test item. The batch equilibrium method resulted Freundlich isotherm coefficients for adsorption KFoc between 775 and 34779 depending on the soil. Based on this study the substance was characterized as poorly mobile in soil.

Two supporting studies are available, which were conducted according to the US EPA Pesticide Assessment Guideline, Subdivision N163-1: Leaching and Adsorption/Desorption studies (1988) and GLP. In the first supporting study (1995) 14C-labeled test substance was tested in four different soil types at 25°C, obtaining log Koc values of 2.5 (sandy loam), 2.8 (silt loam), 3.1 (sand) and 3.6 (clay). In the second supporting study (1985) radiolabeled test material was tested in sandy loam and loamy sand soil at 25°C. The resulting log Koc values were between 2.7 and 4.0.

The studies show that the adsorption potential of the substance strongly depends on the soil properties. However the data show a moderate to high adsorption potential of the substance in soil.