UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF

CHEMICAL SAFETY AND POLLUTION PREVENTION

PC Code: 005210

DP Barcode: 398590

May 8, 2012

MEMORANDUM

SUBJECT: Estimated Drinking Water Concentrations of Sulfoxaflor from Use in 

Cotton (FIFRA Section 18 Emergency Use in Cotton) for the Use in 

Human Health Risk Assessment.

TO: Debra Rate, Risk Manager Reviewer,

Marcel Howard, Risk Manager, Room 09, RIMUERB, 

Registration Division (7505P)

AND Christina Swartz, Branch Chief, RAB 2

Health Effects Division (7509P)

FROM: Mohammed A. Ruhman, Ph.D., Agronomist.

Environmental Risk Branch V, 

Environmental Fate and Effects Division (7507P)

THRU: Mah T. Shamim, Ph.D., Chief

Environmental Risk Branch V, 

Environmental Fate and Effects Division (7507P)

I. Summary

This memo presents the Estimated Drinking Water Concentrations (EDWCs) for the total toxic 

residue resulting from the expected rapid degradation of parent sulfoxaflor (t1⁄2= <1 day) to the toxic 

residues of concern for drinking water. These residues (hereinafter referred to as TTR): parent, main 

degradate X117194-74 (hereinafter referred to as X-474) and degradate of the latter X115195-40

degradate (hereinafter referred to as X-540) for use in an FQPA human health risk assessment for 

section 18 use on cotton.

Sulfoxaflor is characterized by its non-persistence in soil and low affinity to soil/sediment particles. 

The chemical is not expected to partition in significant amount into the air from water in wet and dry 

soils. The degradation profile for sulfoxaflor show very limited abiotic degradation occurring in 
2

laboratory aqueous systems affected or not affected by sunlight. In the soil system, parent transforms 

biologically into a major persistent and highly mobile degradate X-474 that may degrade, in some 

soils to two degradates, namely: X-540 and X-474. The latter two degradates can be considered as 

highly persistent. The Residues of Concern Knowledgebase Subcommittee (ROCKS) decided that the 

residues of concern for drinking water are parent, X-474 and X-540 (DP Barcode D398294, dated 

April 6, 2012). Source of surface water contamination include drift for parent and run-off for X-474

and X-540 following the rapid degradation of parent in the soil. The parent reaching surface water, by 

drift, is expected to degrade rather slowly to X-474. In contrast, the source of ground water 

contamination is expected to be leaching of the highly mobile parent (only if rain and irrigation 

follows application) and its highly mobile degradation products X-474 and X-540.

The screening level EDWCs, from surface water sources, were calculated using Tier II PRZM 

(Pesticide Root Zone Model) and EXAMS (Exposure Analysis Modeling System). Tier I SCI-GROW

(Screening Concentration in Ground Water) model was used for calculating the EDWCs from ground 

water sources. The estimates for both TTS and individual constituents of the TTS are presented in 

Table 1 for surface water (acute “peak” and non-cancer/cancer chronic values) and for

groundwater (acute and chronic values). Modeling included all available cotton scenarios using the 

maximum application rate, maximum number of applications (two applications) and the minimum 

application interval of 5 days. Results in Table 1 are for the highest modeled concentrations.

Table 1 Estimated drinking water concentrations (EDWCs in ppb) for sulfoxaflor parent, X-474, 

X-540 individually and the TTR from surface and ground waters

Scenario Residue(s) of Concern Acute Peak 1 Non-cancer/Chronic 2 Cancer/chronic 3

Surface Water

TX cotton

Parent 2.76 zero zero

X-474 zero 0.761 0.417

X-540 zero 0.104 0.057

Total (TTR) 2.76 0.865 0.474

Ground Water

Not 

Applicable

Parent zero

X-474 39.7

X-540 5.4

Total (TTR) 45.1

1

Peak value; 2 Annual mean values; 3 Overall annual mean values.

Based on the results above, the surface water acute 1-in-10 years peak EDWC is 2.76 ppb for the 

TTR while the surface water non-cancer/chronic 1-in-10 years annual mean EDWC is 0.865 ppb 

for TTR and the 1-10-years overall mean cancer/chronic is 0.474 ppb for TTR. Concentrations for 

individual chemicals are included in Table 1, above.
3

For ground water acute/chronic, EDWCs is 45.1 ppb for TTR. Concentrations for individual 

chemicals are included in Table 1, above.

For the procedure used to estimate of the expected concentrations for the various constituents of the 

TTR, please refer to: EDWCs for the Constituents of the total toxic residue of sulfoxaflor. The above 

stated values represent upper-bound estimates of total concentrations that might be found in surface 

water and ground water due to the use of sulfoxaflor as an insecticide in cotton. If more information 

or refinement is needed, please call Mohammed A. Ruhman at (703) 605-0644.
4

EDWCs for the Constituents of the total toxic residue (TTR) of sulfoxaflor

Degradation profiles for sulfoxaflor in soil and aquatic systems are expected to be the major 

governing factors in determining the constituents of the TTR that are expected to reach surface and 

ground waters. Figures 1 and 2 are conceptual diagramsshowing these governing factors along with 

reasonable estimates of the species present (Figure 1 for ground water and Figure 2 for surface 

water). The conceptual diagrams are based on the degradation profiles of parent and degradate X474/X-540 and on the assumption that the following statement is added to the label: “do not apply 

this product if rain or irrigation is expected within 2-3 days”. The latter statement is expected to 

limit the possibility of parent leaching to ground water and/or transported to surface water by run-off. 

Ground water conceptual diagram

Figure 1 shows the conceptual diagram for ground water.

Figure 1 Conceptual diagram for distribution of expected stressor constituents in ground water

Application of Sulfoxaflor Parent

Plant Foliage: Parent (major)

Soil System: Parent (major)

Wash-off

Drift

Rapid Aerobic Soil Degradation

Parent (minor) X-474 (major)

X-540 (minor)

X-474 (major)

Very Slow Aerobic Soil Degradation

Parent (major)

Direct

Application

None*

None*

Run-off

X-474 (major) + X-540 (minor)

Leaching

Leaching

Ground Water

None*= none is expected to be transported 

Resulting from suggested label restriction

Leaching

Run-off

Run-off

Expected soil 

concentration 

following very 

slow 

degradation 

in the soil 

system

Surface Water

(Refer to 

Figure 2, below)
5

As shown in Figure 1, the exposure value for the TTR, of 45.1 ppb, for ground water may be 

considered from the X-474 degradate and its degradation product X-540. This is because the 

possibility of parent leaching to ground water is expected to be eliminated due to suggested label 

restriction which increases the residence time for parent to degrade completely before it has the 

opportunity leach to ground water. Based on the maximum observed 12% formation of X-540 (from 

X-474) in the soil system, the exposure acute/chronic value of 45.1 ppb may be divided to 39.7 ppb

from X-474 and 5.4 ppb from X-540. It is noted however, that these values are conservative due to 

the following reasons:

(1) The amount of X-474 that is available for leaching is expected to be lowered as a result of its 

expected movement into the plant (X-474 is systemic); 

(2) The amount of X-540 that is available for leaching is expected to be lowered as it depends in

the amount/soil resident time of its parent X-474. X-474 is expected to be leached and 

transported into the plant causing reduction in the amount/soil residue time available for it to 

degrade into X-540; noting that transformation of X-474 into X-540 is expected to occur only 

in the soil system before it reaches ground water (X-474 is hydrolytically stable).

(3) Observed leachate concentrations for chemicals similar to the total toxic residues of 

sulfoxaflor (long half-lives and very low Koc values) in prospective ground water studies were 

observed to be much lower than values predicted by SCIGROW when rates are standardized 

to the maximum rate used for sulfoxaflor. This indicates that SCIGRO predicted EDWCs for 

this chemical might have been overestimated.
6

Surface water conceptual diagram

Figure 2 shows the conceptual diagram for ground water.

Figure 2 Conceptual diagram for distribution of expected stressor constituents in surface water

As shown in Figure 2, expected constituents of sulfoxaflor TTR in surface water, at the acute and 

chronic levels, are govern by the drift contribution and the degradation profile for parent and X-474 in 

aquatic systems in addition to run-off contribution of X-474 and X-540 transported from the soil 

system. Drifted parent sulfoxaflor will be the major species at the short- term and as run-off reaches 

aquatic system (X-474 loading) the major species at the medium-term is expected to be parent + X474. At the long-term parent degrades further to X-474 (X-474 loading) and with run-off (X-474 + X540 loading), the species present are expected to be: X-474 (major) + X-540 (minor); at this time 

frame parent is expected to be long gone due to degradation.

In order to determine the contribution of drift to surface water EDWCs, the chosen scenario was 

modeled with and without drift. Table 2 contains a summary of the results.

Application of Sulfoxaflor Parent

Drift

Parent (Minor)

X-540 (minor)

X-474 (major)

Aquatic Systems: Parent (major)

Slow Aerobic/Anaerobic Aquatic Degradation

Direct Application

Un-degraded Parent (Major)

X-474

(From parent 

degradation) + From 

Run-off)

(Major)

None*

X-540 (minor)

Run-off

Ground Water (refer to Figure 1 above)

Run-off

Run-off

Expected soil concentration following: Fast 

degradation of parent and slow degradation 

of X-474 in the soil system

Plant Foliage: Parent (major)

Soil System: Parent (major)

Surface Water

None*= none is expected to be transported 

Resulting from suggested label restriction

Wash-off
7

Table 2 Estimated drinking water concentrations (EDWCs in ppb) for sulfoxaflor from surface waters

Scenario Exposure Source Acute Peak 1 Non-cancer/Chronic 2 Cancer/chronic 3

TX cotton

(Aerial)

Run-off 2.524 (91.5%) 0.776 (90%) 0.386 (81%)

Drift 0.234 (8.5%) 0.089 (10%) 0.088 (19%)

Total 2.758 (100%) 0.865 (100%) 0.474 (100%)

1

Peak value; 2 Annual mean values; 3 Overall annual mean values.

Results of this modeling exercise suggest that only 8.5% of the modeled acute exposure value of 

2.758 ppb may be considered as acute exposure. This value is equal to 0.234 ppb (2.76 x 0.085= 

0.234) from parent alone as it is the only species reaching surface waters from drift just after 

application. Giving EFED suggested label restriction, 2 to 3 day of parent presence in the soil system 

will cause it to degrade to X-474 before it is transported to surface waters by run-off. The noncancer/Chronic and Cancer/chronic values of 0.865 and 0.474 are expected to be from (X-474 + X540) and concentration may be divided between the two degradates based on the maximum observed 

12% formation of X-540 (from X-474) in the soil system (the source of exposure, X-540 was not 

observed in laboratory aquatic studies). This gives non-cancer/Chronic and Cancer/chronic values of 

0.7611and 0.4172ppb from X-474 and 0.1043and 0.0574ppb from X-540. This is based on the fact 

that the only source of X-540 is run-off following its formation in the aerobic soil system and that the 

maximum X-540 formed from X-474 in the soil was observed to be 12%. Parent is not expected to be 

present at this time frame.

II. Background

Mississippi Department of Agriculture and Commerce have submitted a request for the emergency

use of TransformTM WG insecticide (50% a.i of sulfoxaflor) to control the tarnished plant bug, 

Lygus lineolaris on Cotton. 

Sulfoxaflor (XDE-208; Cyanamide, N-[methyloxido[1-[6-(trifluoromethyl)-3-pyridinyl]ethyl]-

lambda 4-sulfanylidene]; CAS No. 946578-00-3, PC code 005210) consists of two diastereomers 

in a ratio of approximately 50:50. Currently, the chemical is being considered for a new chemical 

registration for many proposed uses including some grains, most vegetables, canola (rapeseed), 

citrus, cotton, low growing berries, ornamentals, turf, most fruit and tree nuts, root and tuber 

vegetables, soybean, succulent/edible and dry beans. 

Sulfoxaflor is a sap-feeding insecticide (i.e. systemic) and is from a new class of insecticides, the 

sulfoxamines. Sulfoxamines act through a unique interaction with the nicotinic acetycholine 

receptor in insects. Relative to neonicotinoids, sulfoxaflor is a highly efficacious agonist of the 

 

1 Value derived as follows: o.865 ppb x 88%= 0.761 ppb

2 Value derived as follows: 0.474 ppb x 88%= 0.417 ppb

3 Value derived as follows: 0.865 ppb – 0.761= 0.104 ppb

4 Value derived as follows: 0.474 ppb – 0.417= 0.057 ppb
8

nicotinic receptor with low binding affinity for the imidacloprid binding site. The structural 

novelty of sulfoxaflor makes it stable in the presence of monooxygenase enzymes that degrade 

neonicotinoids and cause virtually all known cases of neonicotinoid resistance in the field. 

As per the submittal, sulfoxaflor is to be applied by a ground or aerial sprays. The submittals 

stated the following:

Cotton crop is to be treated with a maximum of two applications at a maximum single rate 

of 0.086 lb a.i/A with a minimum of 5-day intervals and a maximum seasonal rate of 0.172 

lb a.i/A;

Cotton acreage to be treated is 300,000 acres; and 

The maximum seasonal usage will be 103,125 lbs of product or 51,562.5 lbs of active 

ingredient.

III. Environmental fate of Sulfoxaflor

Sulfoxaflor is soluble in water (570 ppm @ pH 7). If moisture is available, the chemical is 

expected to be completely soluble and available for leaching given the fact that expected 

concentrations, from single application, is much below 570 ppm on the top 6” of the soil 

(expected concentrations is 0.04 ppm assuming the total single application of 0.086 lb a.i/A 

reaches and mixed in the top 6” of the soil). The chemical is not expected to partition in 

significant amount into the air from water and wet and dry soil (Vapor pressure= 1.88 x 10-6torr 

and calculated Henry’s Law constant= 4.2 x 10-11 atm m3 mol-1 @25 oC). The chemical structures 

and names of diastereomeric pairs are presented in Figure 3.

Figure 3 Sulfoxaflor chemical structure and relevant data
9

Degradation Profile for Sulfoxaflor parent

Based on abiotic laboratory studies, sulfoxaflor is stable to photolysis on soil and to hydrolysis in 

acidic, neutral and alkaline systems (MRIDs: 478320-21 and 478321-49, respectively). Aqueous 

photolysis is expected to be slow and may not be considered an important transformation route in 

the natural environment (t1⁄2 >1,000 days in de-ionized water and 637 days in natural water; 

MRIDs: 478322-83/84, respectively). In the aerobic soil system, sulfoxaflor degrades rather 

quickly to its major degradate X-474 (90th percentile t1⁄2= 0.4 days, n=8 and a range of <0.1 to 0.6 

days). In eight US and EU soils, sulfoxaflor reached non detection within one day in one soil, 3-4 

days in five soils, and 7-14 days in two soils (MRIDs 478655-78 & 478320-13). Other residues, 

forming as a result of aerobic soil biotransformation, includes limited amounts of two 

transformation products (Maximums 9-12%) of degradates X-11579-57 and X-540. Anaerobic 

soil data suggest that anaerobic conditions produces the main degradate X-474 and with very 

limited amount of CO2 from much slower rate of transformation than aerobic conditions (MRIDs 

478322-79 & 478320-13). In contrast to the rapid degradation of sulfoxaflor in aerobic soil 

systems, the chemical degrades rather slowly to X-474 in both aerobic and anaerobic aquatic 

conditions (MRIDs 478320-14 & 473723-11 with 90th percentile t1⁄2= 141 days, n=2 & 672 days, 

n=2, and a range of 37 to 88days & 103 to 382 days, respectively). Based on laboratory studies, 

Figure 4 summarizes expected degradation pathway in important compartments of the natural 

environment for parent sulfoxaflor and degradates.
10

N

S

N O

F3C

NH2

O

N

S

NH O

F3C

N

S

O

O

F3C

Figure 4 Expected environmental degradation pathways and transformation profiles for 

Sulfoxaflor

* Half-lives were >1,000 days in US soils with no degradates observed. In contrast, half-lives ranged from 85-381 

days in EU soils producing degradate X-540 & X115794-57. Separate aerobic soil experiments showed that both of 

these degradates are persistent (90th percentile half-lives were 526 days (range 96 to 670 days) for X115794-57 and 

2,808 days (range 71 to 3,630 days) for X-540

In the field, sulfoxaflor dissipated rapidly, mainly by degradation, in the top 6” of the soil into its 

main degradate X-474 (observed half-lives: in bare-plots= 0.3 to 2 .0 days in CA, FL, ND, ON and

8.1 days in TX; in cropped plots, half-lives ranged from 0.1 to 1.9 days). Generally, field data for 

sulfoxaflor transformation agrees with that predicted from laboratory data.

Sulfoxaflor Degradation Products

As shown in Figure 4, above, only one major and two minor degradates are expected to be 

important in the natural environment; X-474 (major degradate) and X-540 and X115794-57 

(minor degradates). The minor photolysis degradate X117210-61 is expected to form only in 

shallow clear surface waters at low concentrations. Additionally, the degradate X-117189-22 is 

expected to be of minor importance as it is expected to form by aqueous photolysis from the 

highly persistent degradate X-474. 

Rapid Bio-degradation 

(90th percentile t1⁄2= 

0.4 days)

(Aerobic Soil System)

Slow Aqueous 

Photolysis

(t1/2= 261 days)

Very Slow Aqueous 

Photolysis

(Practically Stable)

Sulfoxaflor 

Parent

X117210-61

X117189-22

X-474

X-540 X115794-57

Very Slow 

Biodegradation*

(90th percentile t1⁄2= 

825 days)

(Aerobic Soil 

System)
11

Data suggest that the major transformation product X-474 is persistent to highly persistent in the 

soil system (t1⁄2 range from 85-381 days in tested EU soils and is >1,000 days in tested US soils). 

Relative persistence was also observed for the minor degradates X-540 and X115794-57 in the 

same aerobic soil systems. In separate aerobic soil metabolism studies on these two degradates (as 

a test substance), calculated half-lives ranged from 71 to >1,000 days for X-540 and from 96 to 

670 days for X115794-57.

Mobility for Sulfoxaflor parent and Degradates

Laboratory mobility data suggest that sulfoxaflor and all degradates is of similar high mobility. 

Adsorption coefficients (Koc’s) were determined for many soils with varied characteristics in pH, 

organic matter and texture. Determined Koc ranged from 7 to 68 mL g-1for parent, 7 to 74 mL g-1

for X-474, 1-25 mL g-1for X-540 and 2-44 mL g-1for X115794-57. In the soil system, parent is 

not expected to be persistent but is expected to be highly mobile. Parent low persistence reduces 

the likelihood for leaching into ground water in spite of its high mobility; unless leaching occurs 

within few days of application. In contrast, the relative high persistence for sulfoxaflor degradates, 

(X-474 degradate and its degradate X-540), coupled by expected high mobility suggests high 

possibility for these degradates to contaminate ground water in most soils.

IV. Estimating Drinking Water Exposure from Surface Water Sources

Sulfoxaflor is a new insecticide and no surface water monitoring data is available. For this reason, the 

Agency based this report on simulated screening values using Tier II PRZM/EXAMS. The screening 

assessment for sulfoxaflor was completed using Tier II PRZM/EXAMS program for drinking water. 

The following steps were taken to perform a model run for section 18 use pattern on cotton:

(1) Determination of Application Parameters

Currently suggested label, for section 18 on cotton, includes a maximum single application rate of 

0.086 lb a.i/A (0.0964 kg a.i/ha), a maximum of 2 applications and a minimum of 5-day interval. 

The maximum seasonal label rate is 0.172 lb a.i/A (0.193 kg a.i/ha).

(2) Determination of Stressor

The Residues of Concern Knowledgebase Subcommittee (ROCKS) decided that the residues of 

concern for drinking water are parent, X-474 and X-540. In an agricultural setting, sulfoxaflor is 

expected to be applied into variable density foliage of growing crops; depending on application 

timing. Upon application, only limited quantities of the pesticide is expected to be carried away 

by drift (to adjacent terrestrial and aquatic systems) with the important part being deposited into 

target plants and later affected by wash-off into the soil for the part that did not enter the plant 

tissues (parent is systemic). 
12

Sulfoxaflor deposited on the plant foliage is affected by its systemic nature. Plant residue data 

indicate that it enters the plant and is incorporated into the plant foliage with only limited 

degradation. The same data also suggest that the degradate X-474 is also systemic and enters the 

plant from the soil (following rapid parent degradation). Parent entering the plant through foliage 

and X-474 entering the plant from soil may be a source of exposure depending on the agricultural 

practices for plant residues. This exposure pathway is not considered here because it is difficult to 

assess as it is highly dependent on the type of plant and density of the foliage (application timing 

and plant type). In contrast, sulfoxaflor reaching the soil system from foliage wash-off will be 

subjected to rapid degradation to X-474 (main soil degradate) which degrades, in some soils, very 

slowly producing relatively low concentrations of X-540 and X115794-57. Parent may be 

transported by run-off and/or leached to groundwater only if heavy rain follows application to 

soils vulnerable to erosion and/or leaching. In contrast, persistent and highly mobile X-474 is 

expected to be highly affected by run-off and leaching causing surface and groundwater 

contamination. Another source of surface/ground water contamination, by degradate X-474 and to 

less extent parent, is plant residue left after the crop is harvested; this exposure is not considered 

here. 

Sulfoxaflor carried away by drift to adjacent terrestrial systems will be subjected to the processes 

described above. However, sulfoxaflor reaching aquatic systems is expected to persist longer than 

that reaching the soil. This is due to the fact that sulfoxaflor shows relative stability to 

biodegradation in aquatic systems and it is stable to hydrolysis and aqueous photolysis is not a 

major route of degradation (especially in most aquatic system which is not clear and shallow).

(1) Scenarios and Input Parameters Used in modeling

Three standard scenarios were used for modeling to represent the major cotton areas of the United 

States. The scenarios are NC cotton, TX cotton and MS cotton. Other input parameters used in 

modeling are included in Table 3. The parameters, including half-lives, were re-calculated for the 

stressor, the total toxic residue from radioactivity data. The method for calculating some of the 

input parameters and the basis for choosing the others are also included in Table 3. All runs were 

based on two application at a single rate of 0.0964 kg a.i/ha. The first application was chosen to 

be early July for one set of modeling runs and August, 7 for a second set of modeling runs.
13

Table 3 Summary of PRZM/EXAMS input parameters for modeling Sulfoxaflor TTR

Input Parameter (Unit) Value Reference (MRID No) and Notes

Molecular Weight g/mole 277.27 Product chemistry

Henry’s constant (atm-m

3 

mol-1 @ 20 oC) 1.2 x 10-11 Calculated

Solubility in Water(mg/L) 570 Product chemistry

Photolysis in Water (t1⁄2 in

days @ pH 7) Stable

Because the only photolysis degradate is included

(MRID 478322-83) 

Aerobic Soil Metabolism 

(90th % t1⁄2 in days) 2,332

Range for US soils= 1,386 to 2,310 compared to 

136 to 578 in EU soils

(MRIDs 478655-78 and 478320-13)

Hydrolysis (90th % t1⁄2 in 

days) Stable

All degradates are stable

(MRID 478321-49) 

Aerobic Aquatic 

Metabolism (Whole system 

t1⁄2 in days) 1,761

(MRID 478320-14)

Range from 289 to 1,733, the low half-life is 

associated with 1.7% CO2

Anaerobic Aquatic 

Metabolism (Whole system 

t1⁄2 in days) 655

(MRID 478322-77)

Range from 131 to 495, the low half-life is 

associated with high Un-extractable residue (25%)

Kfoc (Average in L Kg-1) 30

(MRID 478320-14)

Use Kfoc for the dominant Degradate -74

Noting that Kfoc for parent= 35 L kg-1 and for 

X115195-40= 14 L kg-1

Chemical Application 

Method (CAM) 2

Parameter Guidance5

Application Efficiency

95% for aerial

99% for ground

Spray Drift Fraction

Aerial (0.16)

Ground: Airblast (0.063) 

and 

others (0.064)

Table 4 contains only the results obtained for the scenario with the highest EDWCs6resulting 

from aerial and ground application on cotton. 

 

5 Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of 

Pesticides. URL http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

6 Highest EDWCs were chosen from Twelve model simulations (Three scenarios “NC cotton, TX cotton 

and MS cotton” x Two application dates x Two application methods; 3 x 2 x 2= 12)
14

Table 4 The highest estimated drinking water concentrations (EDWCs) for sulfoxaflor residue in 

surface water

Scenario Application Type Acute Peak 1 Non-cancer/Chronic 2 Cancer/chronic 3

Surface Water

TX cotton Air 2.76 0.865 0.474

1

Peak value; 2 Annual mean values; 3 Overall annual mean values.

IV. Estimating Drinking Water Exposure from Ground Water Sources

Sulfoxaflor is a new insecticide and no ground water monitoring data is available. For this reason, the 

Agency used Tier I SCI-GROW model, a high exposure tier one model, for arriving at the Estimated 

Drinking Water Concentrations (EDWCs) for this chemical in ground water sources. Table 5

summarizes the inputs and Table 6 contains a summary of the output. 

Table 5 Summary of SCI-GROW input parameters for fluopyram

Parameter Value* Reference (MRID Number)

Application Rate (lb a.i./acre)

Number of Applications/Year 0.086 x 2

Refer to (1), above” Determination of Application 

Parameters”

Aerobic Soil Metabolism t1⁄2 (days) 987 Median of 8 values (MRIDs 478655-78 & 478320-13

Koc (L Kg-1) 23 Median of 17 values (MRID 478320-18)**

* As per Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides. 

Referenced above

** Median value for the dominant chemical in the residue of concern; that is X-474, noting that the median value for 

parent is slightly higher (31 L Kg-1) and for X-540 is much lower (13 L Kg-1).

Table 6 Summary of output from SCI-GROW for fluopyram

Parameter Modeled Value (ppb) Reference

EDWC (2 applications) 45.1 Output form model run & Corrected output form model run
15

References

Section 18 Application-Sulfoxaflor, Mississippi Cotton, Submitted by the Mississippi Department 

of Agriculture and Commerce, P.O Box 5207, Mississippi State, MS 39762 ; February 2, 2012

MRID 47832149

Laughlin, L. A., 2009, Hydrolysis of XDE-208 at pH 5, 7, and 9, Dow AgroSciences LLC. Report 

Number: 070102, Report Date: 3-Mar-2009; 38 pages.

MRID 47832283

M. Ma, 2010, Aqueous Photolysis of XDE-208 and X11719474 in pH 7 Buffer Under Xenon 

Light, Dow AgroSciences LLC. Report Number: 090073, Report Date: 6-May-2010; 86 pages.

MRID 47832284

R. N, Yoder, 2010, Natural Water Photolysis of XDE-208 and the X11719474 Metabolite under 

Xenon Light, Dow AgroSciences LLC. Report Number: 090088, Report Date: 1-Apr-2010;69 

pages.

MRID 47832014

Laughlin, L. A., Adelfinskaya, Y., Balcer, J. L., 2010, Aerobic Transformation of XDE-208 in 

Two European Aquatic Sediment Systems, Dow AgroSciences LLC. Report Number: 080138, 

Report Date: 18-Mar-2010. 97 pages.

MRID 47832277

R. N. Yoder, A. G. Stephon., 2010, Anaerobic Aquatic Degradation of XDE-208 in Two US 

Sediment and Pond Water Systems, Dow AgroSciences LLC. Report Number: 070105, Report 

Date: 8-Jun-2010. 83 pages.

MRID 47832018

R. N. Yoder., D. Liu, 2010, Adsorption/Desorption of XDE-208 and Adsorption of Three XDE208 Soil Metabolites, Dow AgroSciences LLC. Report Number: 080161, Report Date: 4-Jan2010. 153 pages. 

MRID 47865578

D. Liu, R. N. Yoder, Y. A. Adelfinskaya, 2010, Aerobic Degradation of XDE-208 in Four US 

Soils, Dow AgroSciences LLC. Report Number: 080130, Report Date: 11-Jun-2010. 107 pages. 

MRID 47832013

R. N. Yoder, A. G. Stephon, J. L. Balcer, 2009. Aerobic and Anaerobic Degradation of XDE-208 

in Four European Soils, Dow AgroSciences LLC. Report Number: 080129, Report Date: 8-Sep-
16

2009. 177 pages. 

MRID 47832279

M Simmonds, 2010, XDE-208: Degradation in One Soil under Anaerobic Conditions Following 

Incubation under Aerobic Conditions. Battelle UK Ltd, for Dow AgroSciences LLC. Report 

Number: YR/09/011 (DAS Number: 101398), Report Date: 13-Jul-2010. 98 pages.

MRID 47832013

R. N. Yoder, A. G. Stephon, J. L. Balcer, 2009. Aerobic and Anaerobic Degradation of XDE-208 

in Four European Soils, Dow AgroSciences LLC. Report Number: 080129, Report Date: 8-Sep2009. 177 pages. 

MRID 47832280

B. M. Wendelburg, 2010, Aerobic Soil Degradation Rate of X11579457 in 4 European Soils, 

Dow AgroSciences LLC. Report Number: 080146, Report Date: 29-Jun-2010. 109 pages. 

MRID 47832281

B. M. Wendelburg, 2010, Aerobic Soil Degradation Rate of X11519540 in 4 European Soils, 

Dow AgroSciences LLC. Report Number: 080147, Report Date: 28-Jun-2010. 105 pages.