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Endpoint:
adsorption / desorption: screening
Type of information:
experimental study
Adequacy of study:
key 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.

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

Zinc bis dimethyldithiocarbamate shows low to moderate adsorption potential to solid particles (log Koc of 2.5 - 4).

Key value for chemical safety assessment

Additional information

The adsorption potential of zinc bis dimethyldithiocarbamate (CAS No. 137-30-4) was investigated in two studies. The key study (Spare, 1995) was conducted according to US EPA Guideline, Subdivision N163-1, Leaching and Adsorption/Desorption studies (1988), under GLP conditions.14C-labeled Ziram 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). An additional study on adsorption/desorption of this substance is available (Warren, 1985). This test was also conducted according to US EPA Guideline, Subdivision N163-1, under GLP conditions. Radiolabeled material was tested in sandy loam and loamy sand soil types at 25°C (two replicates per soil). The resulting log Koc values were 2.7 and 3.0 for the sandy loam soil and 3.6 and 4.0 for the loamy sand soil.