UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

PC Code: 123009 

DP Barcodes: DttO'O"ta7; 'it>llf,l., 

MEMORANDUM 

SUBJECT: 

TO: 

FROM: 

THROUGH: 

Drinking Water Exposure Assessment for a Proposed Increase of the 

maximum use rate ofTopramezone Frequency Herbicide (EPA Reg. No. 

7969-281) for non-cropland1 

uses, and Proposed New Use for Direct 

Applications to Aquatic Environments (Oasis Aquatic Herbicide, EPA File 

Symbol No. 7969-GGO) 

Charles Smith, Acting Branch Chief, RAB 1 

~arah Levy, Chemist 

Health Effects Division (7509P) 

Kathryn Montague, RM23 

Grant Rowland, Risk Manager Reviewer 

Registration Division (7505P) 

James K. Wolf, Ph.D., Environmental. Scientist t k LJ~ 

Rosanna Louie-Juzwiak, RAPL ~ - 1/2.<7J /1c I 3 

Environmental Fate and Effects Division iii!_ 

James A. Hetrick, Ph.D., Senior ScientisU~tt., '-'\ ~- 'v<- 1/2.'1 ( ~1.3 · 

Environmental 

Dana Spatz, Branch 

Fate and 

Chief, 

Effects 

Environmental 

Division (7507P)~~ 

Risk Bran~ ~ 

~ 

l) 2.'\ \'ZA~ 

BASF has requested to increase application rates for several registered non-cropland terrestrial 

uses of topramezone, and a proposed new use for direct applications in water bodies to manage 

aquatic vegetation. For the terrestrial uses, the registrant is seeking to amend the Frequency 

herbicide label (EPA Reg.# 7969-281) to increase the maximum use single application rate from 

0.022 to 0.0875 pound of active ingredient (lb a.i.)/A) for sequential use, to increase the 

maximum single application rate to 0.35 lb a.i./A for bare ground, Christmas, conifer and 

1 For preemergence and post-emergence weed control in Christmas tree, conifer, and hardwood plantations; field grown 

ornamental production; and non-cropland areas such as railroad, utility, highway, and pipeline rights-of-way; highway 

guardrails, delineators, and sign posts; utility substations, petroleum tank farms, pumping installations, farmyards and around 

farm buildings; fence rows, storage areas, airports, and nonirrigation ditches. 

1 
2 

hardwood plantations use, to increase the maximum annual rate from 0.0875 lb a.i./A to 0.35 lb 

a.i./A. For the direct aquatic applications, BASF proposed that a concentration of 50 parts per 

billion (ppb) be maintained for up to 60 days, with the exception of certain treated water bodies 

that may be used for sources of potable water with functional potable water intakes must not 

exceed 45 ppb. 

To date, no monitoring data are available for parent topramezone. Only parent topramezone is 

considered in this drinking water assessment because the degradation products are not considered 

in the tolerance expression for topramezone2

. The models used in this assessment include 

PRZM/EXAMS models for surface water and Tier 1 PRZM-GW and SCI-GROW models for 

ground water. This assessment is based upon model input parameters from a previous drinking 

water assessment for topramezone (Hetrick and Corbin, 20083

). An additional anaerobic aquatic 

metabolism4 study (MRID 48600413) was submitted since the previous assessment, and was 

considered in this assessment. Given the proposed duration and concentration for the direct 

aquatic use, the highest concentration recommended for acute and chronic exposure 

considerations of drinking water is 45 ppb.

The highest topramezone EDWC is expected to result from the direct aquatic applications. 

Although the highest proposed concentration in water is 50 ppb, the proposed use for water 

bodies with functional potable water intakes cannot exceed 45 ppb; therefore, this is the highest 

potential concentration recommended for drinking water. EDWCs concentrations resulting from 

terrestrial uses for both surface water and ground water generally occurred when the maximum 

application rate was applied in a single application. The surface water 1 in 10-year acute (peak) 

EDWC value is 31.2 μg/L, the chronic (annual mean) value is 12.5 μg/L, and the long term (30-

year) mean is 7.2 μg/L, based on the maximum application rate to bare ground. The highest 

ground water EDWCs were influenced by scenario, years of application, and length of 

simulation. The highest daily EDWC in ground water was 15.4 μg/L. The highest simulation 

average and breakthrough average ground water EDWCs were 11.3 μg/L and 11.4 μg/L, 

respectively. Whether one 0.35 lb a.i./A application or four 0.0875 lb a.i./A applications were 

simulated, little difference was noted in EDWCs for a specific scenario. 

Use Characterization 

Terrestrial Applications

The registrant (BASF) is seeking to amend the Frequency herbicide label (EPA Reg. # 7969-

281) to increase the maximum use single application rate from 1 to 4 fl oz/A (0.022 to 0.0875 lb 

active ingredient (a.i.)/A) for sequential use, to increase the permitted maximum single 

application rate to 16 fl oz/A (0.35 lb a.i./A for bare ground use and conifer/hardwood use, 

 

2

 Clock-Rust, M. et al. Memorandum: Topramezone/BAS670H: Human Health Risk Assessment for New Active 

Ingredient. DP Barcode 390075, May 11, 2005. 3 Hetrick, J.A. and M. Corbin. Topramezone Tier 1 and 2 Drinking Water Assessment DP Barcode 356497, September 29, 2008. 4

 OCSPP Guideline 835.4400 Anaerobic Aquatic Metabolism of 14C-BAS 670 H. 
3 

which would also increase the maximum annual rate from 4 to 16 fl oz/A (0.0875 lb a.i./A to 

0.35 lb a.i./A). 

Direct Aquatic Applications

BASF is also requesting the first use of topramezone for direct aquatic applications, including 

direct foliar applications made to floating, emergent, and shoreline weeds, which specifies a 

maximum annual application rate of 16 fluid ounces (0.35 lb a.i.) per acre. The proposed Oasis 

product label (EPA File Symbol 7969-GGO) also includes directions for in-water applications to 

control submersed or floating aquatic weeds. Depending on the level of weed establishment and 

desired control of target weeds, proposed labeling directions include instructions to maintain a 

concentration ranging from 10 – 50 ppb throughout the treatment; depending on the target 

species to control, treatment durations can continue for at least 60 days. Depending on the type 

of weed control or to control more established or mature weeds, application exposures may take 

as long as four months at effective concentrations to achieve the desired control. Treated areas 

with functional potable water intakes must not exceed concentrations of 45 ppb, or treated 

potable water sources must be restricted (held) until levels decrease to 45 ppb or less. The 

proposed new rates are summarized in Table 2. Although reapplication intervals for the 

sequential use were not specified on the label, the registrant indicated via email (J. Birks, 

12/21/12) that the minimum reapplication interval should be 30 days; therefore, all modeling is 

based on this minimum retreatment interval. 

 
4 

Table 2: New Maximum Single and Seasonal (Annual) Proposed Application (App) Rates for Topramezone 

Crop/Site 

Reference 

Label 

Page1

App Type/ 

Method 

 Single App 

Rate 

(lb a.i./A) 

Max. 

Number 

Of Apps 

Max. App 

Rate/ Season 

(Year)

(lb a.i./A) 

Min. 

Retreat 

Interval 

(days)2

Noncropland3 Use 

Applications 

(Frequency Label, EPA 

Reg. No. 7969-281) 

5 & 8 

Aerial (A)/ 

Ground 

(G) 

 0.35 30 

Bare Ground: 

Pre-emergent app 

 Early post-emergent app 

8 A/G 

A/G 

0.0875-0.35 

0.0875-0.35 

14

-45

14

-45

0.35 

0.35 30 

Christmas Tree 

Plantation 8 G 0.0875 45

 0.35 30 

Conifer & Hardwood 

Plantations: Site Prep. 

Applications 

8 A/G 0.0875 42,5 0.35 30 

Conifer & Hardwood 

Plantations: Herbaceous 

Weed Control 

9 A/G 0.0875 42,5 0.35 30 

Field-Grown 

Ornamentals 9 A/G 0.0875 45

 0.35 30 

Selective Weeding 10 A/G 0.0875 45 0.35 30 

Direct Aquatic 

Applications (Oasis 

label, EPA File Symbol 

No. 7969-GGO) 

 

Foliar Application to 

shoreline or floating 

vegetation, dewatered 

canals, exposed sediment 

4, 11 A/G 0.0875-0.35 

0.0875-0.35 

1-4 

1-4 

0.35 

0.35 none 

In-water applications to 

water bodies without

functional drinking water 

intakes 

4, 9, 11 G 10 – 50 ppb none 50 ppb none 

In-water applications to 

water bodies that may be 

a potable water source 

4, 9, 11 G 10 - 45 ppb none 50 ppb none 

1

 Draft label 007969-00281.20120509.NVA 2012-04-325-0095 (Submission #: 918739; E-Sub #: 2971). 

2

 Minimum reapplication interval is 30-day per email communication from J.H. Birk, BASF via K. Montague, 

USEPA, 12/21/12 and yearly maximum is 16 fl oz./A/year (0.35 lb a.i./A/year). 

3 Non-cropland areas include railroad, utility, highway, and pipeline rights-of-way; highway guardrails, delineators, 

and sign posts; utility substations, petroleum tank farms, pumping installations, farmyards and around farm 

buildings; fence rows, storage areas, airports, and nonirrigation ditchbanks. 

4

 Only one application per season can be made at the maximum single application rate (16 fl. oz/acre = 0.35 lb a.i/A) 

More than one sequential applications can be made at a lower single application rates (0.0875 lb a.i./A), the 

maximum number of applications is not specified (the max application rate cannot exceed 0.35 lb a.i./A/year); the 

minimum retreatment interval is 30 days. 

5 The number of applications is not specified on the proposed label; the number was calculated by dividing the total 

seasonal application rate proposed by the single maximum application rate proposed: (16 oz / 4 oz). 
5 

Exposure Characterization

Topramezone is persistent and mobile in terrestrial and aquatic environments. Major routes of 

dissipation are expected to be anaerobic microbial-mediated degradation, leaching, surface water 

runoff, and spray drift. These data suggest a high potential for off-site movement of topramezone 

into surface and ground water. Degradation products of topramezone include M670H05, and 

M670H01, M670H 10, and M670H05 are also persistent and mobile. The degradation products 

are not considered in the drinking water assessment because they are not considered residues of 

concern by the Health Effects Division. 

 

Environmental Fate and Transport Properties 

Major routes of dissipation for topramezone are anaerobic microbial-mediated degradation, 

leaching, surface water runoff, and spray drift. Topramezone is stable in sterile solutions at pH 4, 

5, 7, and 9 at temperatures ranging from 25 to 50°C. In natural water, topramezone has a 

photodegradation half-life of 72 days. The average aerobic soil metabolism half-life of five soils 

was 197.0 days. Topramezone degrades to form M670H05 (15% of applied parent at 365 days), 

and M670H01 (> 15% of applied), M670H 10 (>16% of applied). The degradation product 

M670H05 is mobile and persistence (t1/2 > 350 days). Structures of these degradation products 

are shown in Appendix A. 

In aerobic aquatic environments, topramezone degraded with total system half-lives ranging 

from 19 to 277 days. Topramezone degraded in aerobic aquatic environments to form M670H01 

(<10.3% of applied) degradation product. In anaerobic environments, topramezone degraded 

with total system half-lives ranging from 13 to 24 days. The major degradation products 

identified in anaerobic aquatic environments were M670H10 (41% to 48% of applied) minor 

degradation products and M670H01 (≤5.3% of applied). Based upon soil organic carbon 

coefficient, Koc, topramezone would fall into the mobile to moderately mobility class adapted 

from the FAO by EFED (USEPA, 20065). 

Terrestrial field dissipation studies were conducted in Indiana, South Dakota, California, and 

Ontario (Canada). Linear half-lives ranged from 29 to 182 days. There was no evidence of 

leaching in the terrestrial field dissipation studies.

Modeling 

EFED water models6

 were used to estimate the drinking water exposure for use in the dietary 

risk assessment of topramezone. The following is a description of the models used, the selection 

of the model input parameters, and a characterization of the output from these simulations. 

Representative input and/or output are included in Appendix B. 

 

5

 USEPA, 2006. Standardized Soil Mobility Classification Guidance. Memorandum: S. Bradbury, April 21, 2006. 6 PRZM and EXAMS are Tier II models used to estimate environmental exposure concentrations in surface water. A 

description of these models and the guidelines for selecting input parameters can be found at 

http://www.epa.gov/oppefed1/models/water/
6 

Surface Water: The linked7 Tier 2 PRZM 3.12.28/ EXAMS 2.98.04.069) models were used to 

assess potential for contamination of surface drinking water sources from the proposed rate 

increases for terrestrial uses of topramezone. Only the scenarios that resulted in the highest 

EDWCS from the previous non-cropland assessment (D356497) and the California right-of-way 

scenarios were considered in this assessment. For the proposed direct aquatic applications, EFED 

assumed that this concentration could be available in surface water sources that may feed into a 

drinking water intake, based on the proposed concentration of 45 to 50 ppb, and the duration of 

maintaining the target concentration (i.e., for up to 60 days at the higher concentrations, and for 

up to four months at lower concentrations). 

Groundwater: For groundwater assessments, EFED is using both the SCI-GROW10 (v2.3, Jul. 

29, 2003) model and PRZM-GW (v1.0111). The output of SCI-GROW represents the 

concentrations of topramezone residues that might be expected in shallow, unconfined aquifers 

under sandy soils. However, SCI-GROW does not consider multiple years of application and 

does not estimate a peak concentration. 

PRZM-GW can be used for Tier 1 and 2 assessments and additional refinements, provided data 

are available. Various exposure scenarios (i.e., as for surface water) can also be considered. 

PRZM-GW also allows for modeling multiple years of application. PRZM-GW does not 

consider dilution within the aquifer and or degradation processes other than aerobic soil 

metabolism in the upper meter of the soil, unless data are available for other processes within the 

vadose zone or within the aquifer. 

Model Input Parameters

The environmental fate and other input parameters used for modeling are summarized in Tables 

3, 4, and 5. Dates of first application considered for surface water modeling with 

PRZM/EXAMS are listed in Table 6. The date of first application (Table 7) had little influence 

on the EDWCs (results not shown) estimated for ground water by PRZM-GW. The SCI-GROW 

model does not consider application date.

Topramezone can be applied by ground and aerial methods. Only aerial spray is considered in 

this assessment as this method results in higher EDWCs. Two rate options were assessed: 1) one 

application at the maximum rate of 0.35 lb a.i./A and 2) four applications at the maximum 

sequential application rate (0.0875 lb a.i./A) with a 30 day reapplication interval, for a yearly 

maximum of 0.35 lb a.i./A. For optimal control, topramezone is applied to meet specific weed 

growth conditions; therefore, it can be applied during the period of active weed growth. To 

address the temporal (seasonal) variability, a number of initial application dates were considered 

(Table 6). 

 

7 http://www.epa.gov/oppefed1/models/water/index.htm#przmexamsshell

8 http://www.epa.gov/oppefed1/models/water/index.htm#przm

9 http://www.epa.gov/oppefed1/models/water/index.htm#exams

10 http://www.epa.gov/oppefed1/models/water/#scigrow 11 http://www.epa.gov/oppefed1/models/water/#przm_gw
7 

Table 3. Topramezone Input Parameters for PRZM and EXAMS – Surface Water 

Parameter Value/Selection criteria Source

Maximum Application Rate per Year, 

lb a.i./A 

 0.35 lb topramezone/A Proposed label of 

Topramezone 

(Frequency herbicideA) 

Maximum Single Application Rates (lb 

a.i./A) 

1 application @ 0.35 lb topramezone/A 

4 applications @ 0.0875 lb topramezone/A 

30-day minimum reapplication interval 

Proposed label of 

Topramezone 

Application Method and Depth of 

Incorporation (cm) 

Ground and Aerial Spray 

No incorporation (model default 4-cm) 

Proposed label of 

Topramezone 

Soil Partition Coefficient (Kads; mL/g) mean Kads = 2.8 

 (n = 6; 1.40, 2.30, 1.97, 4.87, 2.59, 3.69) 

45902425 

Aerobic Soil Metabolism Half-life 

(days) [Linear t1⁄2] 

241.28days (90th percent upper bound of 

mean) 

(n=5; 181.3, 182.0, 301.5, 124.5, 195.9) 

45902419; 45902421 

Spray Drift Fraction (ground spray / 

aerial) 

Drinking Water: 0.064/0.16 USEPA, 2009B

Application Efficiency (ground spray / 

aerial) 

0.99 / 0.95 USEPA, 2009B

Molecular Weight, Daltons 363.39 Physical and Chemical 

Property 

Vapor Pressure 7.5 * 10-13 torr Physical and Chemical 

Property 

Henry’s Law Constant 2.39 * 10-17 atm-m-3mol-1 @ 20 ◦C Estimated 

Solubility in Water at 20oC 

Topramezone is a weak acid (pKa 4.6) 

The solubility of topramezone is pH 

dependent 

15,000 mgL-1 Physical and Chemical 

Property 

Aerobic Aquatic Metabolism Half-life 

(days) 

229.97 days (90th percent upper bound of 

mean) 

(n=4; 18.6, 18.99,203, 277) 

47496702 

Anaerobic Aquatic Metabolism Halflife (days) 32.81 days 90th percent upper bound of 

mean total system 

(n = 4; 13.4, 18.6 and 47.4, 23.4) 

45902423 

48600413 

Hydrolysis Half-life @ pH 7 (days) Stable 45902416 

Aquatic, Direct Photolysis Half-life @ 

pH 7 

0 45902417 

A EPA Reg No. 7969-281 (007969-00281.20120509.NVA 2012-04-325-0095) and Correspondence from J.Birks, BASF 

 (Table 1)

B

 USEPA, 2009. Guidance for Selecting Input Parameters for Modeling the Environmental Fate and Transport of Pesticide. 

http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm 
8 

Table 4.Input Parameters Used for SCI-GROW – Ground Water 

Parameter Value/Selection criteria Source

Maximum Application Rate per 

Season, lb a.i./A 

0.35 lb topramezone/acre Proposed label of 

Topramezone 2.8SC 

Aerobic Soil Metabolism Half-life 

(days) [Linear t1⁄2] 

197.04 days mean 

(n=5; 181.3, 182.0, 301.5, 124.5, 195.9) 

45902419 

45902421 

Sorption Koc 105.5 median Koc 

(38, 284, 53, 120, 91, 303) 

45902425 

Table 5.Input Parameters Used for PRZM-GW – Ground Water 

Parameter Value/Selection criteria Source

Maximum Application Rate per 

Season, lb a.i./A 

4 applications at 0.089 lb a.i./A 

1 application at 0.35 lb a.i./A 

Proposed label of 

Topramezone 2.8SC 

Aerobic Soil Metabolism Half-life 

(days) [Linear t1⁄2] 

241.28days (90th percent upper bound of 

mean) 

(n=5; 181.3, 182.0, 301.5, 124.5, 195.9) 

45902419; 45902421 

Sorption Kads mean Kads = 2.8 

 (n = 6; 1.40, 2.30, 1.97, 4.87, 2.59, 3.69)

45902425 

Surface Water Exposure Assessment 

By design, all existing PRZM scenarios are intended to represent high-end exposure scenarios 

for the region represented whether it is a national, regional, or local scenario. Results of the 

surface water EDWCs are presented in Table 6. Because this assessment is based upon the 

previous drinking water assessment for the non-cropland use (DP Barcode 356497), the only 

scenarios (with aerial applications) considered in this assessment are those with the highest 

surface water EDWC from the previous drinking water assessment. The highest EDWCS were 

associated with a single maximum rate of 0.35 lb a.i./A compared to four sequential applications 

of 0.0875 lb a.i./A. 

 
9 

Table 6. PRZM/EXAMS Estimated Maximum Surface Water EDWCs (μg/L)A for the proposed new use rate 

of topramezone on non-cropland. 

 Scenario 1st

Application 

Date (mn/day)

Number 

apps/rate 

(lb a.i./A/app)

1-in 10-year 

peak Annual mean 30 year mean 

μg/L 

TN Nursery 03/05 1 app @ 035 14.715 3.542 1.794 

04/05 1 app @ 0.35 14.655 3,442 1.689 

05/05 1 app @ 0.35 8.2573 2.063 1.442 

06/05 1 app @ 0.35 10.328 2.533 1.499 

07/05 1 app @ 0.35 9.0274 2.252 1.612 

03/05 4 app @ 0.0875 6.344 2.479 1.624 

04/05 4 app @ 0.0875 6.493 2.129 1.566 

05/05 4 app @ 0.0875 6.151 2.069 1.558 

06/05 4 app @ 0.0875 6.759 2.257 1.749 

07/05 4 app @ 0.0875 7.996 2.453 1.864 

NJ Nursery 03/05 1 app @ 0.35 14.298 4.577 2.726 

04/05 1 app @ 0.35 10.879 3.430 2.154 

05/05 1 app @ 0.35 11.494 3.493 2.201 

06/05 1 app @ 0.35 8.318 2.625 2.122 

07/05 1 app @ 0.35 10.728 3.493 2.534 

08/05 1 app @ 0.35 4.888 3.052 

 

03/05 4 app @ 0.0875 7.241 3.176 2.318 

04/05 4 app @ 0.0875 6.429 2.842 2.244 

05/05 4 app @ 0.0875 8.723 3.041 2.593 

06/05 4 app @ 0.0875 7.737 3.388 2.672 

07/05 4 app @ 0.0875 8.179 3.667 2.850 

08/05 4 app @ 0.0875 8.515 4.436 2.894 

MI Nursery 03/05 1 app @ 0.35 7.325 2.685 1.930 

04/05 1 app @ 0.35 11.298 3.760 2.613 

05/05 1 app @ 0.35 11.455 4.026 2.567 

06/05 1 app @ 0.35 8.543 3.158 2.543 

07/05 1 app @ 0.35 7.506 2.616 2.361 

08/05 1 app @ 0.35 11.312 3.276 2.504 

 

03/05 4 app @ 0.0875 6.529 2.9649 2.354 

04/05 4 app @ 0.0875 6.310 3.0694 2.498 

05/05 4 app @ 0.0875 6.045 2.8866 2.515 

06/05 4 app @ 0.0875 8.975 3,653 2.706 

07/05 4 app @ 0.0875 8.143 3.5832 2.612 

08/05 4 app @ 0.0875 

PA turf 03/05 1 app @ 0.35 4.470 2.558 2.067 

04/05 1 app @ 0.35 4.264 2.484 1.975 

05/05 1 app @ 0.35 5.394 2.918 2.280 

06/05 1 app @ 0.35 5.976 2.981 2.457 

07/05 1 app @ 0.35 6.109 3.511 2.462 

08/05 1 app @ 0.35 8.380 4.723 3.006 

09/05 1 app @ 0.35 11.615 5.755 3.367 

 
10 

 Scenario 1st

Application 

Date (mn/day)

Number 

apps/rate 

(lb a.i./A/app)

1-in 10-year 

peak Annual mean 30 year mean 

μg/L 

03/05 4 app @ 0.0875 3.081 1.934 1.648 

04/05 4 app @ 0.0875 3.354 2.081 1.763 

05/05 4 app @ 0.0875 4.305 2.645 2.012 

06/05 4 app @ 0.0875 4.997 2.955 2.201 

07/05 4 app @ 0.0875 5.321 2.974 2.287 

Bare Ground 

CA R-O-WB

 

(Aerial) 1/15 1 app @ 0.35 31.17 12.53 7.02 

(Ground) 1/15 1 app @ 0.35 31.05 12.46 6.73 

(Aerial) 2/15 1 app @ 0.35 23.81 9.22 4.78 

(Ground) 2/15 1 app @ 0.35 23.27 9.02 4.41 

(Aerial) 3/15 1 app @ 0.35 16.68 6.79 3.94 

(Ground) 3/15 1 app @ 0.35 15.98 6.49 3.53 

(Aerial) 4/15 1 app @ 0.35 12.40 4.88 3.01 

(Aerial) 5/15 1 app @ 0.35 12.57 4.53 3.38 

(Aerial) 6/15 1 app @ 0.35 14.18 4.93 3.62 

(Aerial) 7/15 1 app @ 0.35 15.61 5.32 3.91 

(Aerial) 8/15 1 app @ 0.35 17.27 5.74 4.24 

(Aerial) 9/15 1 app @ 0.35 19.33 6.25 4.69 

(Aerial) 10/15 1 app @ 0.35 16.50 7.24 5.08 

(Aerial) 11/15 1 app @ 0.35 23.92 7.77 5.89 

(Aerial) 12/15 1 app @ 0.35 28.91 11.54 6.93 A – No PCA applied. 

B- California Right-of-Way Scenario 

Ground Water Exposure Assessment 

 

The previous drinking water assessment only presented SCI-GROW estimates of topramezone 

concentrations in ground water. PRZM-GW is now used in addition to SCI-GROW to estimate 

pesticide concentrations in ground water12. Both PRZM-GW (Table 8) and SCI-GROW (Table 

9) are presented for the proposed new application rates. Simulations were run for 30 and 100 

years for the maximum single application rate of 0.35 lb a.i./A and for four sequential 

applications of 0.0875 lb a.i./A following the guidance for using PRZM-GW13. The highest daily 

ground water EDWC value was 15.4 μg/L for a vulnerable scenario in Florida. The highest 

simulation average and breakthrough average EDWCs were 11.3 μg/L and 11.4 μg/L, 

respectively. Whether one 0.35 lb a.i./A application or four 0.0875 lb a.i./A applications were 

simulated, little difference was noted in EDWCs for a specific scenario. 

 

 

12 Brady, D. Approval of PRZM-GW for Use in Drinking Water Exposure Assessments. December 11, 2012. 

13 USEPA, 2012. Guidance for Using PRZM-GW in Drinking Water Exposure Assessments; 

 http://www.epa.gov/oppefed1/models/water/przm_gw/wqtt_przm_gw_guidance.htm 

 
11 

Table 7. PRZM-GW Estimated Maximum Ground Water EDWCs (μg/L) for the proposed new use rate of 

topramezone on non-cropland. 

Scenario: Date of First 

Application (mn/day) Years of 

Simulation 

Highest 

Daily Value 

Simulation 

Average 

Post 

Breakthrough 

Average 

Average 

Simulation 

Breakthrough 

Time (days) 

Max. Single App Rate 

# apps: 1@ 0.35 lb a.i./A μg/L

Delmarva: 5/05 30 

100 

0.77 

8.59 

0.10 

4.46 

0.10 

4.48 

238 

243 

Fl Citrus: 2/05- 30 

100 

11.0 

15.4 

3.49 

11.3 

3.62 

11.4 

260 

260 

FL Potato: 1/05 30 

100 

5.04 

5.99 

1.99 

4.57 

2.10 

4.64 

302 

301 

GA Coastal Plain: 5/05 30 

100 

0.138 

5.33 

0.02 

2.68 

0.02 

2.78 

1036 

1033 

NC East Coastal Plain: 5/05 30 

100 

0.136 

5.15 

0.016 

2.17 

0.018 

2.23 

1076 

1086 

WI Central Sands: 7/05 30 

100 

<0.001 

5.39 

<0.001 

0.826 

<0.001 

0.846 

612 

614 

Max. Sequential App Rate 

# apps: 4 @ 0.0.875/30-day μg/L

Delmarva: 5/05 30 

100 

0.774 

 8.79 

0.10 

 4.55 

0.10 

 4.58 

238 

243 

Fl Citrus: 2/05- 30 

100 

10.8 

 15.1 

3.39 

11.0 

3.51 

11.1 

260 

260 

FL Potato: 1/05 30 

100 

4.85 

 5.77 

1.91 

4.39 

2.01 

 4.46 

302 

301 

GA Coastal Plain: 5/05 30 

100 

0.14 

5.41 

0.017 

 2.72 

0.019 

 2.82 

1035 

1033 

NC East Coastal Plain: 5/05 30 

100 

0.14 

 5.38 

0.017 

 2.25 

0.018 

2.32 

1076 

1086 

WI Central Sands: 7/05 30 

100 

<0.001 

 5.40 

<0.001 

 0.82 

<0.001 

 0.84 

612 

614 

The modeling results associated with maximum allowable rate per year from SCI-GROW is 

presented in Table 8. 

Table 8. SCI-GROW estimated EDWCs (μg/L) in the ground water for maximum application rate. 

Model for Groundwater EEC (μg/L) 

SCI-GROW 1.07 

 
12 

APPENDIX A 

Structure of Topramezone and Degradation Products

Topramezone 

 M670H05 M670H01 

 

M670H 1 

M670H10 

S

O

N

N

OH

O

S

N

O

N

N

O

O

OH

O

S

N

O

OH

O

O

O

S

N

N

N

O

O

OH

O
13 

APPENDIX B 

Representative Model Output Files 

Surface Water 

PE5 PRZM-EXAMS OUTPUT 

stored as CAROW1a.out 

Chemical: topramezone 

PRZM environment: CArightofwayRLF_V2.txt modified Wedday, 26 March 2008 at 

09:38:28 

EXAMS environment: ir298.exv modified Tueday, 26 August 2008 at 05:14:08 

Metfile: w23234.dvf modified Tueday, 26 August 2008 at 05:15:38 

Water segment concentrations (ppb) 

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly 

1961 13.8 13.61 13.23 12.22 11.38 5.707 

1962 20.73 20.55 19.62 17.65 16.15 8.516 

1963 31.19 30.83 30.12 27.26 25.2 12.68 

1964 25.97 25.65 24.3 21.47 19.65 9.838 

1965 8.394 8.281 8.013 7.322 7.004 3.983 

1966 15.41 15.2 14.44 12.97 11.92 5.998 

1967 48.18 47.55 46.23 41.51 38.02 18.76 

1968 24.77 24.43 23.2 21.12 19.54 10.02 

1969 31.05 30.79 29.7 26.77 24.56 12.19 

1970 21.89 21.62 20.92 18.88 17.31 8.75 

1971 9.97 9.834 9.294 8.657 7.969 4.387 

1972 6.411 6.324 5.975 5.463 5.056 2.802 

1973 32.13 31.69 30.12 27.6 25.38 12.57 

1974 9.852 9.728 9.244 8.388 8.062 4.636 

1975 18.45 18.24 17.7 16.04 14.73 7.379 

1976 10.56 10.41 9.832 8.745 8.01 4.295 

1977 7.099 7.002 6.618 5.827 5.305 3.091 

1978 17.9 17.65 16.88 15.48 14.56 7.451 

1979 17.93 17.73 16.97 15.44 14.15 7.517 

1980 16.11 15.89 15.28 13.67 12.51 6.536 

1981 23.55 23.31 22.1 19.58 17.93 8.968 

1982 12.98 12.81 12.23 11.08 10.17 5.498 

1983 25.74 25.53 24.37 21.85 20 9.889 

1984 5.274 5.216 4.937 4.565 4.428 2.515 

1985 13.17 12.99 12.25 11.64 10.86 5.552 

1986 12.17 12.05 11.48 10.39 9.668 5.075 

1987 10.89 10.75 10.15 9.054 8.26 4.258 

1988 13.33 13.14 12.43 10.95 9.975 5.54 

1989 5.802 5.723 5.573 5.317 5.046 2.854 

1990 8.277 8.198 7.767 6.851 6.234 3.38 
14 

Sorted results 

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly 

0.032258064516129 48.18 47.55 46.23 41.51 38.02 18.76 

0.0645161290322581 32.13 31.69 30.12 27.6 25.38 12.68 

0.0967741935483871 31.19 30.83 30.12 27.26 25.2 12.57 

0.129032258064516 31.05 30.79 29.7 26.77 24.56 12.19 

0.161290322580645 25.97 25.65 24.37 21.85 20 10.02 

0.193548387096774 25.74 25.53 24.3 21.47 19.65 9.889 

0.225806451612903 24.77 24.43 23.2 21.12 19.54 9.838 

0.258064516129032 23.55 23.31 22.1 19.58 17.93 8.968 

0.290322580645161 21.89 21.62 20.92 18.88 17.31 8.75 

0.32258064516129 20.73 20.55 19.62 17.65 16.15 8.516 

0.354838709677419 18.45 18.24 17.7 16.04 14.73 7.517 

0.387096774193548 17.93 17.73 16.97 15.48 14.56 7.451 

0.419354838709677 17.9 17.65 16.88 15.44 14.15 7.379 

0.451612903225806 16.11 15.89 15.28 13.67 12.51 6.536 

0.483870967741936 15.41 15.2 14.44 12.97 11.92 5.998 

0.516129032258065 13.8 13.61 13.23 12.22 11.38 5.707 

0.548387096774194 13.33 13.14 12.43 11.64 10.86 5.552 

0.580645161290323 13.17 12.99 12.25 11.08 10.17 5.54 

0.612903225806452 12.98 12.81 12.23 10.95 9.975 5.498 

0.645161290322581 12.17 12.05 11.48 10.39 9.668 5.075 

0.67741935483871 10.89 10.75 10.15 9.054 8.26 4.636 

0.709677419354839 10.56 10.41 9.832 8.745 8.062 4.387 

0.741935483870968 9.97 9.834 9.294 8.657 8.01 4.295 

0.774193548387097 9.852 9.728 9.244 8.388 7.969 4.258 

0.806451612903226 8.394 8.281 8.013 7.322 7.004 3.983 

0.838709677419355 8.277 8.198 7.767 6.851 6.234 3.38 

0.870967741935484 7.099 7.002 6.618 5.827 5.305 3.091 

0.903225806451613 6.411 6.324 5.975 5.463 5.056 2.854 

0.935483870967742 5.802 5.723 5.573 5.317 5.046 2.802 

0.967741935483871 5.274 5.216 4.937 4.565 4.428 2.515 

0.1 31.176 30.826 30.078 27.211 25.136 12.532 

 Average of yearly averages: 7.02116666666666 

Inputs generated by pe5.pl - Novemeber 2006 

Data used for this run: 

Output File: CAROW1a 

Metfile: w23234.dvf 

PRZM scenario: CArightofwayRLF_V2.txt 

EXAMS environment file: ir298.exv 

Chemical Name: topramezone 

Description Variable Name Value Units Comments 
15 

Molecular weight mwt 363.39 g/mol 

Henry's Law Const. henry 2.39E-17 atm-m^3/mol 

Vapor Pressure vapr 7.5E-13 torr 

Solubility sol 15000 mg/L 

Kd Kd 2.8 mg/L 

Koc Koc mg/L 

Photolysis half-life kdp 0 days Half-life 

Aerobic Aquatic Metabolism kbacw 229.97 days Halfife 

Anaerobic Aquatic Metabolism kbacs 32.81 days Halfife 

Aerobic Soil Metabolism asm 241.28 days Halfife 

Hydrolysis: pH 7 0 days Half-life 

Method: CAM 2 integer See PRZM manual 

Incorporation Depth: DEPI cm 

Application Rate: TAPP 0.392 kg/ha 

Application Efficiency: APPEFF 0.95 fraction 

Spray Drift DRFT 0.16 fraction of application rate applied to pond 

Application Date Date 15-1 dd/mm or dd/mmm or dd-mm or dd-mmm 

Record 17: FILTRA 

 IPSCND 1 

 UPTKF 

Record 18: PLVKRT 

 PLDKRT 

 FEXTRC 0.5 

Flag for Index Res. Run IR Reservoir 

Flag for runoff calc. RUNOFF total none, monthly or total(average of entire run) 

Surface Water 

PRZM INPUT FILE 

"CarightofwayRLF_V2.txt, 3/25/2008" 

"Central/Coastal California; MLRA 14,15; Metfile: W23234.dvf" 

*** Record 3: 

 0.77 0 0 17.5 1 1 

*** Record 6 -- ERFLAG 

 4 

*** Record 7: 

 0.28 1.1 1 172.8 2 5 600 

*** Record 8 

 1 

*** Record 9 

 1 0.1 15 10 3 92 92 92 0 15 

*** Record 9a-e 

 1 24 

0109 1609 0110 1610 0111 1611 0112 1612 0101 1601 0102 1602 0103 1603 0104 1604 

.004 .004 .004 .004 .004 .004 .004 .004 .004 .004 .004 .004 .004 .004 .004 .004 

.110 .110 .110 .110 .110 .110 .110 .110 .110 .110 .110 .110 .110 .110 .110 .110 
16 

 92 92 92 92 92 92 92 92 92 92 92 92 92 92 92 92 

0105 1605 0106 1606 0107 1607 0108 1608 

.004 .004 .004 .004 .004 .004 .004 .004 

.110 .110 .110 .110 .110 .110 .110 .110 

 92 92 92 92 92 92 92 92 

*** Record 10 -- NCPDS, the number of cropping periods 

 30 

*** Record 11 

 010961 011161 021161 1 

 010962 011162 021162 1 

 010963 011163 021163 1 

 010964 011164 021164 1 

 010965 011165 021165 1 

 010966 011166 021166 1 

 010967 011167 021167 1 

 010968 011168 021168 1 

 010969 011169 021169 1 

 010970 011170 021170 1 

 010971 011171 021171 1 

 010972 011172 021172 1 

 010973 011173 021173 1 

 010974 011174 021174 1 

 010975 011175 021175 1 

 010976 011176 021176 1 

 010977 011177 021177 1 

 010978 011178 021178 1 

 010979 011179 021179 1 

 010980 011180 021180 1 

 010981 011181 021181 1 

 010982 011182 021182 1 

 010983 011183 021183 1 

 010984 011184 021184 1 

 010985 011185 021185 1 

 010986 011186 021186 1 

 010987 011187 021187 1 

 010988 011188 021188 1 

 010989 011189 021189 1 

 010990 011190 021190 1 

*** Record 12 -- PTITLE 

topramazone - 1 applications @ 0.392 kg/ha 

*** Record 13 

 30 1 0 0 

*** Record 15 -- PSTNAM 

topramazone 

*** Record 16 

 150161 0 2 0.0 0.392 .95 .16 
17 

 150162 0 2 0.0 0.392 .95 .16 

 150163 0 2 0.0 0.392 .95 .16 

 150164 0 2 0.0 0.392 .95 .16 

 150165 0 2 0.0 0.392 .95 .16 

 150166 0 2 0.0 0.392 .95 .16 

 150167 0 2 0.0 0.392 .95 .16 

 150168 0 2 0.0 0.392 .95 .16 

 150169 0 2 0.0 0.392 .95 .16 

 150170 0 2 0.0 0.392 .95 .16 

 150171 0 2 0.0 0.392 .95 .16 

 150172 0 2 0.0 0.392 .95 .16 

 150173 0 2 0.0 0.392 .95 .16 

 150174 0 2 0.0 0.392 .95 .16 

 150175 0 2 0.0 0.392 .95 .16 

 150176 0 2 0.0 0.392 .95 .16 

 150177 0 2 0.0 0.392 .95 .16 

 150178 0 2 0.0 0.392 .95 .16 

 150179 0 2 0.0 0.392 .95 .16 

 150180 0 2 0.0 0.392 .95 .16 

 150181 0 2 0.0 0.392 .95 .16 

 150182 0 2 0.0 0.392 .95 .16 

 150183 0 2 0.0 0.392 .95 .16 

 150184 0 2 0.0 0.392 .95 .16 

 150185 0 2 0.0 0.392 .95 .16 

 150186 0 2 0.0 0.392 .95 .16 

 150187 0 2 0.0 0.392 .95 .16 

 150188 0 2 0.0 0.392 .95 .16 

 150189 0 2 0.0 0.392 .95 .16 

 150190 0 2 0.0 0.392 .95 .16 

*** Record 17 

 0 1 0 

*** Record 18 

 0 0 0.5 

*** Record 19 -- STITLE 

"Gaviota Sandy Loam, 5-15% slopes, hydrologic group D" 

*** Record 20 

 51 0 0 0 0 0 0 0 0 0 

*** Record 26 

 0 0 0 

*** Record 33 

 3 

 1 10 1.55 0.173 0 0 0 

 0.0028730.002873 0 

 0.1 0.173 0.087 0.44 2.8 

 2 23 1.55 0.173 0 0 0 

 0.0028730.002873 0 
18 

 1 0.173 0.087 0.44 2.8 

 3 18 1.55 0.136 0 0 0 

 0.0028730.002873 0 

 3 0.136 0.066 0.15 2.8 

***Record 40 

 0 

 YEAR 10 YEAR 10 YEAR 10 1 

 1 

 1 ----- 

 7 YEAR 

 PRCP TCUM 0 0 

 RUNF TCUM 0 0 

 INFL TCUM 1 1 

 ESLS TCUM 0 0 1.0E3 

 RFLX TCUM 0 0 1.0E5 

 EFLX TCUM 0 0 1.0E5 

 RZFX TCUM 0 0 1.0E5 

PRZM-GW INPUT FILE. 

1/29/2013 10:08:30 AM; Topramezone ; Florida Citrus - FL Central Ridge, Polk County - 

(Tampa) Met File (12842.dvf) - Astatula sand, hrgb A 

User Interface Version: PRZM-GW (Version 1.01) 

***Record 3 

 0.78 0 0 33 1 1 

***Record 6 

 0 

***Record 8 

 1 

***Record 9 

 1 0.25 200 60 1 10 10 10 0 100 

***Record 10 

 99 

***Record 11 

 0101 1 0102 1 3112 1 1 

 0101 2 0102 2 3112 2 1 

 0101 3 0102 3 3112 3 1 

 0101 4 0102 4 3112 4 1 

 0101 5 0102 5 3112 5 1 

 0101 6 0102 6 3112 6 1 

 0101 7 0102 7 3112 7 1 

 0101 8 0102 8 3112 8 1 

 0101 9 0102 9 3112 9 1 

 010110 010210 311210 1 

 010111 010211 311211 1 
19 

 010112 010212 311212 1 

 010113 010213 311213 1 

 010114 010214 311214 1 

 010115 010215 311215 1 

 010116 010216 311216 1 

 010117 010217 311217 1 

 010118 010218 311218 1 

 010119 010219 311219 1 

 010120 010220 311220 1 

 010121 010221 311221 1 

 010122 010222 311222 1 

 010123 010223 311223 1 

 010124 010224 311224 1 

 010125 010225 311225 1 

 010126 010226 311226 1 

 010127 010227 311227 1 

 010128 010228 311228 1 

 010129 010229 311229 1 

 010130 010230 311230 1 

 010131 010231 311231 1 

 010132 010232 311232 1 

 010133 010233 311233 1 

 010134 010234 311234 1 

 010135 010235 311235 1 

 010136 010236 311236 1 

 010137 010237 311237 1 

 010138 010238 311238 1 

 010139 010239 311239 1 

 010140 010240 311240 1 

 010141 010241 311241 1 

 010142 010242 311242 1 

 010143 010243 311243 1 

 010144 010244 311244 1 

 010145 010245 311245 1 

 010146 010246 311246 1 

 010147 010247 311247 1 

 010148 010248 311248 1 

 010149 010249 311249 1 

 010150 010250 311250 1 

 010151 010251 311251 1 

 010152 010252 311252 1 

 010153 010253 311253 1 

 010154 010254 311254 1 

 010155 010255 311255 1 

 010156 010256 311256 1 

 010157 010257 311257 1 
20 

 010158 010258 311258 1 

 010159 010259 311259 1 

 010160 010260 311260 1 

 010161 010261 311261 1 

 010162 010262 311262 1 

 010163 010263 311263 1 

 010164 010264 311264 1 

 010165 010265 311265 1 

 010166 010266 311266 1 

 010167 010267 311267 1 

 010168 010268 311268 1 

 010169 010269 311269 1 

 010170 010270 311270 1 

 010171 010271 311271 1 

 010172 010272 311272 1 

 010173 010273 311273 1 

 010174 010274 311274 1 

 010175 010275 311275 1 

 010176 010276 311276 1 

 010177 010277 311277 1 

 010178 010278 311278 1 

 010179 010279 311279 1 

 010180 010280 311280 1 

 010181 010281 311281 1 

 010182 010282 311282 1 

 010183 010283 311283 1 

 010184 010284 311284 1 

 010185 010285 311285 1 

 010186 010286 311286 1 

 010187 010287 311287 1 

 010188 010288 311288 1 

 010189 010289 311289 1 

 010190 010290 311290 1 

 010191 010291 311291 1 

 010192 010292 311292 1 

 010193 010293 311293 1 

 010194 010294 311294 1 

 010195 010295 311295 1 

 010196 010296 311296 1 

 010197 010297 311297 1 

 010198 010298 311298 1 

 010199 010299 311299 1 

***Record 12 

Place Holder 

***Record 13 

 99 1 0 0 
21 

***Record 15 

Place Holder 

***Record 16 

 5 2 1 0 1 4 0.392 1 0 

 5 2 2 0 1 4 0.392 1 0 

 5 2 3 0 1 4 0.392 1 0 

 5 2 4 0 1 4 0.392 1 0 

 5 2 5 0 1 4 0.392 1 0 

 5 2 6 0 1 4 0.392 1 0 

 5 2 7 0 1 4 0.392 1 0 

 5 2 8 0 1 4 0.392 1 0 

 5 2 9 0 1 4 0.392 1 0 

 5 210 0 1 4 0.392 1 0 

 5 211 0 1 4 0.392 1 0 

 5 212 0 1 4 0.392 1 0 

 5 213 0 1 4 0.392 1 0 

 5 214 0 1 4 0.392 1 0 

 5 215 0 1 4 0.392 1 0 

 5 216 0 1 4 0.392 1 0 

 5 217 0 1 4 0.392 1 0 

 5 218 0 1 4 0.392 1 0 

 5 219 0 1 4 0.392 1 0 

 5 220 0 1 4 0.392 1 0 

 5 221 0 1 4 0.392 1 0 

 5 222 0 1 4 0.392 1 0 

 5 223 0 1 4 0.392 1 0 

 5 224 0 1 4 0.392 1 0 

 5 225 0 1 4 0.392 1 0 

 5 226 0 1 4 0.392 1 0 

 5 227 0 1 4 0.392 1 0 

 5 228 0 1 4 0.392 1 0 

 5 229 0 1 4 0.392 1 0 

 5 230 0 1 4 0.392 1 0 

 5 231 0 1 4 0.392 1 0 

 5 232 0 1 4 0.392 1 0 

 5 233 0 1 4 0.392 1 0 

 5 234 0 1 4 0.392 1 0 

 5 235 0 1 4 0.392 1 0 

 5 236 0 1 4 0.392 1 0 

 5 237 0 1 4 0.392 1 0 

 5 238 0 1 4 0.392 1 0 

 5 239 0 1 4 0.392 1 0 

 5 240 0 1 4 0.392 1 0 

 5 241 0 1 4 0.392 1 0 

 5 242 0 1 4 0.392 1 0 

 5 243 0 1 4 0.392 1 0 
22 

 5 244 0 1 4 0.392 1 0 

 5 245 0 1 4 0.392 1 0 

 5 246 0 1 4 0.392 1 0 

 5 247 0 1 4 0.392 1 0 

 5 248 0 1 4 0.392 1 0 

 5 249 0 1 4 0.392 1 0 

 5 250 0 1 4 0.392 1 0 

 5 251 0 1 4 0.392 1 0 

 5 252 0 1 4 0.392 1 0 

 5 253 0 1 4 0.392 1 0 

 5 254 0 1 4 0.392 1 0 

 5 255 0 1 4 0.392 1 0 

 5 256 0 1 4 0.392 1 0 

 5 257 0 1 4 0.392 1 0 

 5 258 0 1 4 0.392 1 0 

 5 259 0 1 4 0.392 1 0 

 5 260 0 1 4 0.392 1 0 

 5 261 0 1 4 0.392 1 0 

 5 262 0 1 4 0.392 1 0 

 5 263 0 1 4 0.392 1 0 

 5 264 0 1 4 0.392 1 0 

 5 265 0 1 4 0.392 1 0 

 5 266 0 1 4 0.392 1 0 

 5 267 0 1 4 0.392 1 0 

 5 268 0 1 4 0.392 1 0 

 5 269 0 1 4 0.392 1 0 

 5 270 0 1 4 0.392 1 0 

 5 271 0 1 4 0.392 1 0 

 5 272 0 1 4 0.392 1 0 

 5 273 0 1 4 0.392 1 0 

 5 274 0 1 4 0.392 1 0 

 5 275 0 1 4 0.392 1 0 

 5 276 0 1 4 0.392 1 0 

 5 277 0 1 4 0.392 1 0 

 5 278 0 1 4 0.392 1 0 

 5 279 0 1 4 0.392 1 0 

 5 280 0 1 4 0.392 1 0 

 5 281 0 1 4 0.392 1 0 

 5 282 0 1 4 0.392 1 0 

 5 283 0 1 4 0.392 1 0 

 5 284 0 1 4 0.392 1 0 

 5 285 0 1 4 0.392 1 0 

 5 286 0 1 4 0.392 1 0 

 5 287 0 1 4 0.392 1 0 

 5 288 0 1 4 0.392 1 0 

 5 289 0 1 4 0.392 1 0 
23 

 5 290 0 1 4 0.392 1 0 

 5 291 0 1 4 0.392 1 0 

 5 292 0 1 4 0.392 1 0 

 5 293 0 1 4 0.392 1 0 

 5 294 0 1 4 0.392 1 0 

 5 295 0 1 4 0.392 1 0 

 5 296 0 1 4 0.392 1 0 

 5 297 0 1 4 0.392 1 0 

 5 298 0 1 4 0.392 1 0 

 5 299 0 1 4 0.392 1 0 

***Record 17 

 0 3 0 

***Record 19 

Place Holder 

***Record 20 

 400 0 0 0 0 0 2 1 1 0 

***Record 26 

 0 0 0 

***Record 27 

 4 0.1 0.90 7.0 

***Record 31 

 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.97 10.0 

***Record 32 

 21 21 21 21 21 21 21 21 21 21 21 21 

***Record 32A 

 2.00 25.0 

***Record 33 

 8 

*** Record 34,36,37 Horizon 1 

 1 10 1.35 0.11 0 0 0 

 0.00287 0.00287 0 

 1 0.11 0.014 0.144 2.8 

 21 96 2.4 0 0 

*** Record 34,36,37 Horizon 2 

 2 10 1.58 0.1 0 0 0 

 0.00271 0.00271 0 

 5 0.1 0.016 0.144 2.8 

 21 95 2.8 0 0 

*** Record 34,36,37 Horizon 3 

 3 20 1.58 0.1 0 0 0 

 0.00223 0.00223 0 

 20 0.1 0.016 1.44 2.8 

 21 95 2.8 0 0 

*** Record 34,36,37 Horizon 4 

 4 20 1.45 0.2 0 0 0 

 0.0016 0.0016 0 
24 

 20 0.2 0.015 0.144 2.8 

 21 95 2.8 0 0 

*** Record 34,36,37 Horizon 5 

 5 20 1.5 0.1 0 0 0 

 0.0009570.000957 0 

 20 0.1 0.015 0.144 2.8 

 21 95 2.8 0 0 

*** Record 34,36,37 Horizon 6 

 6 20 1.5 0.24 0 0 0 

 0.0003190.000319 0 

 20 0.24 0.015 0.144 2.8 

 21 95 2.8 0 0 

*** Record 34,36,37 Horizon 7 

 7 200 1.59 0.10 0 0 0 

 0 0 0 

 50 0.10 0.014 0.144 2.8 

 21 96 2.8 0 0 

*** Record 34,36,37 Horizon 8 

 8 100 1.58 0.3997 0 0 0 

 0 0 0 

 50 0.3997 0.001 0.144 2.8 

 21 87 11 0 0 

*** Record 40 

 0 

*** Record 42 

 YEAR 10 YEAR 10 YEAR 10 0 

*** Record 45 

 3 YEAR 

*** Record 46 

 DCON1 TAVE 21 22 1.0E3 

 INFL TCUM 21 21 0.0261 

 IRRG TSER 
25 

PRZM-GW OUTPUT 

Highest Daily Value (ppb): 15.4 

Simulation Average Value (ppb): 11.3 

Average Breakthrough Time (days): 260.3456 

Throughputs: 138.9 

Post-Breakthrough Average (ppb): 11.4 

Topramezone Simulation 1 application @ 0.35 lb ai/acre per year, 100 year simulation