MEMORANDUM 

SUBJECT: 

TO: 

FROM: 

THRU: 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

Office of Chemical Safety 

and Pollution Prevention 

Date: 06/09/15 

DP Barcode: 425662 

PC Code 129081 

Addendum to the Environmental Fate and Ecological Risk 

Assessment for Sulfentrazone Registra tion Review 

Kelly Sherman, Acting Branch Chief 

Christina Scheltema, Chemical Review Manager 

Risk Management and Implementa tion Branch 3 

Pesticide Re-evaluation Division (7505P) 

Office of Pesticide Programs 

Kathryn V. Montague, PM 23, Herbicide Branch 

And 

Ba rbara Madden, Minor Use Team Leader 

Risk Integration Minor Use, and Emergency Response Branch 

Registration Division (7505C) 

Geoffrey Sinclair, Biologist 

Michael Barrett, Chemist 

Environmental Risk Branch 5 

Environmental Fate and Effects Division (7507P) 

Mah Shamim, Branch Chief /J/YJ_p .,J 11 ,._~AA'--

Environmental Risk Branch 5 // ffY~..=.:.::.::.--­

Environmental Fate and Effects Division (7507P) 

The purpose of this memo is to correct an error in the Registration Review Preliminary 

Ecological Risk Assessment for Sulfentrazonc (June 4, 2014 DP Barcode D409753; abbreviated 

as PRA elsewhere in this document) and provide refinements based on this correction and add 

refinements from belter understanding of application rates and methodologies. A description of 

the error in the terrestrial plant vegetative vigor study endpoint, as well as the changes, 

uncertainties, and potenti al refinements to risk to terrestrial plants and effects distances from the 

site of application needed in order to be below the Level of Concern (LOC) are provided. Risk 

quotients to avian species are also calculated based on the range of usage rates provided by the 

Biological and Economic Analysis Division (BEAD) in the April 6, 2015 memo entitled 

·Sulfentrazone Usage Information'. Preliminary risk assessment citations in this Addendum 

document refer to the 6/4/2014 document. 

1 
2

Modification of the Vegetative Vigor Study IC25 Endpoint for Cucumber

The Environmental Fate and Effects Division (EFED) has reanalyzed the Tier 2 Vegetative 

Vigor Study conducted with sulfentrazone (MRID 43345412). As part of the registration review 

process, the registrant argued that the endpoint for the most sensitive dicot species, cucumber, 

which was used to calculate risk quotients and determine effects distances was not correctly 

calculated. In response to the registrant concerns, the cucumber endpoint was reanalyzed with 

updated statistical models using CETIS version 1.8.7.12 with backend settings approved for use 

by EFED on 5/29/13. This analysis determined the IC25 for cucumber was 0.001617 lbs ai/A

based on dry weight. The IC25 for cucumber will therefore be changed from the previous 

endpoint of 0.00052 lbs ai/A to 0.001617 lbs ai/A. The NOAEC of 0.00044 lbs a.i./A also based 

on dry weight was confirmed as a result of this analysis so the RQs for endangered (listed)

species do not change. The CETIS reports that are associated with the modified DER are 

presented in Appendix A of this Addendum. 

Recalculation of the Risk Quotients for Dicotyledon Species

As a result of the change in the cucumber endpoint, the risk quotients (RQs) for non-listed 

species for the ‘Spray Drift Only’ category changed. This change is bolded in Table 1. No other 

RQs from the TerrPlant output changed as a result of this endpoint change. The resulting RQs 

for non-listed species exposed to spray drift only, as calculated by the EFED model TerrPlant, 

ranged from 0.19 to 2.32. For all crops except turf (with the lowest maximum application rate

the Agency’s level of concern (LOC) was exceeded (i.e. the RQs were 1.0 or greater. Maximum 

label application rates used to calculate the RQs largely bracket the state average application 

rates from 2008-2012 presented in the BEAD Usage memo that range from 0.06 for corn and 

winter wheat to 0.22 lbs. a.i./A for cabbage and strawberries with maximum single application 

rates ranging from 0.19 to 0.38 (Table 2, Chism, Alsadek, Hill, BEAD Usage memo April 6, 

2015).). The average application rates range from 0.061 to 0.221 lb ai/A while application rates 

falling between the 80th and 100th percentile range from 0.06 to 0.31 lb ai/A. 
3

Table 1. Revised dicot RQ values for different application rates of sulfentrazone.

Crop

Single Max. 

Application 

Rate (lbs 

ai/A)

Dicot RQ Values2

Spray Drift Only

Runoff and Runoff and 

Spray Drift Spray Drift

(Dry Areas) (Semi-Aquatic 

Areas)

Nonlisted 

Species*

Listed 

Species

Nonlisted 

Species

Listed 

Species1

Nonlisted 

Species

Listed 

Species1

Apple, Rhubarb, Turnip roots and tops, 

Sunflower Crop Subgroup 20B,Spring 

Wheat,Succulent cowpea,Succulent lima 

beans,Tree nut Crop Group 14 including, 

Citrus Crop,Small berry and fruit Crop 

Group 13-07,Non-grass animal feed Crop 

Group 18,Head/Stem Brassica Subgroup 

5A,Leafy Greens Subgroup 5B,Melon 

Subgroup 9A, Fruiting Vegetable Group 

8,Okra,Succulent Pea, Strawberry and 

Tuberous /Corm Vegetable Subgroup 1C, 

Sugarcane, Cabbage, Potato, Mint, 

Horseradish

0.375 2.32 8.52 2.05 3.75 17.39 31.88

Peanuts 0.3 1.86 6.82 1.64 3 13.91 25.5

Sunflower/field corn/dry bean/dry pea, 

Peanuts incorporated up to 2-4", 

Asparagus

0.25 1.55 5.68 1.36 2.5 11.59 21.25

Brassica 0.22 1.36 5 1.2 2.2 10.2 18.7

Lima bean 0.18 1.11 4.09 0.98 1.8 8.35 15.3

Turf grass 0.03 0.19 0.68 0.16 0.3 1.39 2.55

*Bolded values indicate RQs that have changed from the previous assessment.
4

Recalculation of Effects Distances Based on Revised Endpoint

The spray drift model AgDrift was rerun, using the new endpoint, different droplet sizes (per the 

American Society of Agricultural and Biological Engineers or ASABE), and varying boom 

heights, to estimate effects distance. The boom heights used were 1.27 (high) and 0.5 (low) 

meters above the ground. Droplet size categories used were the default AgDrift values of Dv0.5 = 

175 microns (very fine to fine) and Dv0.5 = 341 microns (fine to medium/coarse) for ground 

applications. The Dv0.5 is the size at which half of the spray volume is smaller and the other half 

is larger than this size. For this assessment, effects distance is defined as the distance from the 

site of application needed in order to be below the LOC. Buffer distances were calculated for 

both ground and aerial application. 

 

Sulfentrazone is a soil-applied, pre-emergent herbicide which can be applied either preplant 

incorporated or preemergence to the weeds. Because sulfentrazone inhibits seed and propagule 

germination it needs to be applied as close to the soil surface as possible with the lowest possible 

amount of pesticide remaining on any leaf surfaces and the minimum amount of exposure to 

evaporation or the wind. For example, the Sulfentrazone XP herbicideTM label says to “apply 

large droplets (>150 - 200 microns) ... setting the boom at the lowest height which provides 

uniform coverage and reduces the exposure of droplets to evaporation and wind.” 

Table 32 in the previous assessment (DP Barcode D409753) presents effects distances for the 

very fine to fine droplet size category (Dv0.5 droplet size = 175 microns). Table 33 in the 

preliminary ecological risk assessment (DP Barcode D409753) presents effects distances for 

both monocots and dicots using fine to medium/coarse particle sizes (Dv0.5 droplet size = 341 

microns). Since the label was ambiguous and allowed a boom height that “provides uniform 

coverage and reduces the exposure of droplets to evaporation and wind’ the AgDrift model is run 

with both high boom height (1.27 meters) and low boom height (0.5 meters). This previous 

assessment only used the highest label application rate of 0.375 lbs a.i./A, the most conservative 

assumption. 

In this recalculation, the AgDrift model was run with all maximum label application rates from 

0.03 to 0.375, which bracket the state average application rates from 2008-2012 presented in the 

BEAD Usage memo that range from 0.01 to 0.4 lbs. a.i./A (Sulfentrazone Usage Information 

(DP #1290841)). The model using very fine to fine droplet sizes encompasses the droplet sizes 

specified on the Sulfentrazone XP herbicideTM label (>150 - 200 microns). The model using fine 

to medium/coarse droplet sizes demonstrates the magnitude of reduction in effects distances that 

might be achieved with larger droplet sizes. This section recalculates the effects distances using 

the newly revised dicot (cucumber) endpoint using both very fine to fine droplet sizes (Table 2)

and fine to medium/coarse droplet sizes (Table 3) at both high and low boom heights. Since 

cucumber is the most sensitive endpoint of either dicot species or monocot species, this 

recalculation represents the most conservative estimate of effects distances. These calculations

may either overestimate or underestimate effects distances depending on actual boom height and 

particle size of the spray. 

Revised Effects Distances from Ground Applications of Sulfentrazone
5

The effects distances generated by the EFED model AgDrift using the revised cucumber IC25 

endpoint are presented in Table 2 and Table 3. The change in the cucumber IC25 only 

influences the effects distances for non-listed species. The listed species effects distances are 

presented for completeness since they were not calculated for all application rates in the PRA. 

From 2008 to 2012, the total treated area ranged from <50 to 3,084,800 acres with average 

application rates that range from 0.06 to 0.22 lb a.i./A (Table 2; Appendix B)

Applications using sprays with a Dv0.5 droplet size of 175 microns (very fine to fine)

Effects distances to mitigate risk for non- listed species from applications using very fine to fine 

droplet sizes ranged from 19 feet using a low boom at the lowest application rate to 656 feet 

using a high boom with the highest application rate (Table 2). Effects distances for listed 

species ranged from 62 feet (low boom, lowest application rate) to greater than 1000 feet (high 

boom, highest application rate). The Sulfentrazone XP herbicideTM label says to “apply large 

droplets (>150 - 200 microns)”. This is similar to the very fine to fine droplet size category used 

by AgDrift which is 175 microns. Table 32 in the previous assessment presents effects

distances that result using the very fine to fine size range at the highest application rate of 0.375 

lbs a.i./A. 

Table 2. Revised effects distances at different application rates of sulfentrazone using a mean 

droplet size of 175 microns.

Ground Application Buffer Distances

Very Fine to Fine Droplet size (175 μm)

High boom (1.27 

m)

Low Boom (0.5m 

height)

Application 

Rate Nonlisted listed Nonlisted listed

0.375 656.16 >1000 242.78 918.62

0.3 564.3 >1000 193.57 757.86

0.25 492.12 921.9 157.48 643.04

0.22 449.47 849.73 137.79 570.86

0.18 383.85 744.74 108.27 472.44

0.03 75.46 183.72 19.68 62.34

Applications using sprays with a Dv0.5 droplet size of 341 microns (fine to medium/coarse)

In high-boom scenarios with coarse droplet sizes, effects distances for non-listed species ranged 

from 9.84 feet to 187.01 feet for the lowest and highest application rates respectively. In low 

boom scenarios effects distances for non-listed species ranged from 6.56 ft to 104.99 ft for the 

lowest and highest rates respectively. Listed species the effects distances were considerably 

larger ranging from 45.93-761.15 ft for high boom scenarios and 22.97-574.14 ft for low boom 

scenarios Table 3. These estimates may underestimate the effects distances needed to eliminate 
6

risk of actual applications if droplet sizes are smaller than the modeled Dv0.5 droplet size of 341 

microns. Table 33 in the previous assessment presents effects distances that result using the fine 

to medium/coarse range at the highest application rate of 0.375 lbs a.i./A. 

 

Table 3. Revised effects distances at different application rates of sulfentrazone using Dv0.5

droplet size of 341 microns.

BUFFER DISTANCES for Coarse droplet sizes for ground application

Fine to Medium Coarse Droplet sized (341 um)

High boom (1.27 m) Low Boom (0.5m height)

Application 

Rate Nonlisted listed Nonlisted listed

0.375 187.01 761.15 104.99 574.14

0.3 141.07 623.35 78.74 425.75

0.25 114.83 524.93 62.34 367.45

0.22 95.14 465.87 52.49 318.24

0.18 75.46 380.57 39.37 249.34

0.03 9.84 45.93 6.56 22.97

BUFFER DISTANCES for Coarse droplet sizes for ground application

Fine to Medium Coarse Droplet sized (341 um)

High boom (1.27 m) Low Boom (0.5m 

height)

Application 

Rate Nonlisted listed Nonlisted listed

0.375 187.01 761.15 104.99 574.14

0.3 141.07 623.35 78.74 425.75

0.25 114.83 524.93 62.34 367.45

0.22 95.14 465.87 52.49 318.24

0.18 75.46 380.57 39.37 249.34

0.03 9.84 45.93 6.56 22.97

Revised Effects Distances from Aerial Applications of Sulfentrazone

Sulfentrazone is applied aerially to soybeans in Arkansas, Illinois, Iowa, and Ohio, and to 

sunflowers in Kansas, North Dakota and South Dakota. From 2008 to 2012, the total treated 

area ranged from 3,700 to acres with average application rates that range from 0.09 to 0.149 lb 

a.i./A (Table 4). Maximum application rates listed on labels of these crops are 0.25 and 0.375 

lbs a.i./A. The effects distances that result from both labeled rates as well as average rates for 

the two most conservative model scenarios using medium to coarse (340 μm) and coarse to very 

coarse (439 μm) droplet sizes are presented in Table 5. Effects distances using the maximum 
7

application rates range from 433 ft to greater than 1000 ft depending on droplet size. Effects

distances that result from average application rates and using coarse to very coarse droplet sizes 

((Dv0.5 droplet size == 439 μm) ranged from 177 feet to 262 feet (Table 5). Use of droplet sizes 

smaller than this would result in larger effects distances to eliminate risk to non-target plants.

Table 4. Sulfentrazone Aerial Application, Total Area Treated (acres) and Application Rate (lb. 

a.i. /acre), Averages for 2009-2013.

Crop State Total Area 

Treated

Average 

Application Rate 

(lb. ai/acre) 

Soybeans Arkansas 3,700 0.090

Soybeans Illinois 57,400 0.136

Soybeans Iowa 3,900 0.120

Soybeans Ohio 28,100 0.131

Sunflowers Kansas 5,600 0.089

Sunflowers North Dakota 12,200 0.122

Sunflowers South Dakota 40,000 0.149

Footnote: Proprietary data 2009 - 2013. All numbers are rounded. All other applications are 

ground applied.
8

Table 5. Aerial application with label rates and average rates. The average rates were provided 

in a memorandum from BEAD (see Appendix B of this Addendum) and are in bold text.

Aerial Application Effects Distances

Coarse to very 

Coarse ((Dv0.5

droplet size = 439 

um)

Medium to Coarse 

((Dv0.5 droplet size

= 340 um)

Application 

Rate Nonlisted listed Nonlisted listed

Maximum Rates Assumed

Sunflower/field corn/dry 

bean/dry pea, Peanuts 

incorporated up to 2-4", 

Asparagus

0.25 433 >1000 778 >1000

Apple, Rhubarb, Turnip roots 

and tops, Sunflower Crop 

Subgroup 20B,Spring 

Wheat,Succulent 

cowpea,Succulent lima 

beans,Tree nut Crop Group 14 

including, Citrus Crop,Small 

berry and fruit Crop Group 13-

07,Non-grass animal feed Crop 

Group 18,Head/Stem Brassica 

Subgroup 5A,Leafy Greens 

Subgroup 5B,Melon Subgroup 

9A, Fruiting Vegetable Group 

8,Okra,Succulent Pea, 

Strawberry and Tuberous /Corm 

Vegetable Subgroup 1C, 

Sugarcane, Cabbage, Potato, 

Mint, Horseradish

0.375 640 >1000 >1000 >1000

Average Rates Assumed

Sunflowers (Kansas), Soybeans 

(Arkansas) 0.09 177 564.3 262 >1000

Soybeans (Iowa), Sunflowers 

(North Dakota) 0.12 220 846.5 335 >1000
9

Aerial Application Effects Distances

Coarse to very 

Coarse ((Dv0.5

droplet size = 439 

um)

Medium to Coarse 

((Dv0.5 droplet size

= 340 um)

Application 

Rate Nonlisted listed Nonlisted listed

Soybeans (Ohio, Illinois) 0.13 236 948.2 361 >1000

Sunflowers (South Dakota) 0.15 262 >1000 410 >1000

Aerial Application Buffer Distances

Coarse to very Coarse 

(droplet = 439 um)

Medium to Coarse 

(droplet = 340 um)

Application 

Rate Nonlisted listed Nonlisted listed

Sunflower/field corn/dry 

bean/dry pea, Peanuts 

incorporated up to 2-4", 

Asparagus

0.25 433 >1000 778 >1000

Apple, Rhubarb, Turnip roots 

and tops, Sunflower Crop 

Subgroup 20B,Spring 

Wheat,Succulent 

cowpea,Succulent lima 

beans,Tree nut Crop Group 14 

including, Citrus Crop,Small 

berry and fruit Crop Group 13-

07,Non-grass animal feed Crop 

Group 18,Head/Stem Brassica 

Subgroup 5A,Leafy Greens 

Subgroup 5B,Melon Subgroup 

9A, Fruiting Vegetable Group 

8,Okra,Succulent Pea, 

Strawberry and Tuberous 

/Corm Vegetable Subgroup 1C, 

Sugarcane, Cabbage, Potato,

Mint, Horseradish

0.375 640 >1000 >1000 >1000

Sunflowers (Kansas), 

Soybeans (Arkansas) 0.09 177 564.3 262 >1000
10

Soybeans (Iowa), 

Sunflowers (North 

Dakota)

0.12 220 846.5 335 >1000

Soybeans (Ohio, Illinois) 0.13 236 948.2 361 >1000

Sunflowers (South 

Dakota) 0.15 262 >1000 410 >1000

Refinement of Chronic Avian RQs to bracket average application rates presented Usage 

Memo

The below RQs are meant to supplement the RQs presented in the assessment after discussions 

with BEAD about usage rates that may be lower than the labeled rates. Table 6 presents the RQs 

based upon both the upper bound and mean Kenaga exposure values along with the approximate 

number of days residues on feed items are expected to remain and exceed the Agency’s level of 

concern (LOC). As stated in the preliminary risk assessment, the mean Kenega exposure values 

are derived from the central tendency of the model with 50% of the predictions being higher than 

the modeled value and 50% of the predictions being lower than the predicted value and it is not 

recommended for use in making risk calculations because it is not sufficiently conservative to 

protect species of concern. The RQs calculated using upper bound Kenaga values exceeded the 

chronic LOC (1.0) for short grass at all application rates. At an application rate of 0.1 a.i./A the 

LOC was exceeded for three dietary items. Only one dietary item at the two highest application 

rates did not exceed the LOC of 1.0. The approximate number of days residues exceed the LOC 

range from zero at the lowest application rates to 100 days at the highest application rates.

Table 6. Chronic avian RQs calculated assuming average application rates

Application 

Rate (lb 

a.i./A)

Upper bound 

Kenaga

Mean 

Kenaga

Approximate 

Number of 

Days Residues 

Exceed LOC

0.3

Short Grass 7.2 2.6 100.0

Tall Grass 3.3 1.1 60.0

Broadleaf plants 4.1 1.4 71.0

Fruits/pods/seeds 0.5 0.2 0.0

Arthropods 2.8 2.0 52.0

0.2

Short Grass 4.8 1.7 78.0

Tall Grass 2.2 0.7 38.0

Broadleaf plants 2.7 0.9 49.0

Fruits/pods/seeds 0.3 0.1 0.0

Arthropods 1.9 1.3 31.0

0.1

Short Grass 2.4 0.9 45.0

Tall Grass 1.1 0.4 6.0

Broadleaf plants 1.4 0.5 16.0

Fruits/pods/seeds 0.2 0.1 0.0

Arthropods 0.9 0.7 0.0
11

0.05

Short Grass 1.2 0.4 11.0

Tall Grass 0.6 0.2 0.0

Broadleaf plants 0.7 0.2 0.0

Fruits/pods/seeds 0.1 0.0 0.0

Arthropods 0.5 0.3 0.0

Uncertainty involved in the use of the acute to chronic ratio (ACR).

An acute to chronic ratio (ACR) was used in lieu of a mysid chronic toxicity endpoint which is 

accompanied by uncertainty in the endpoint for which the ACR is used. In this assessment, (DP 

Barcode D409753), this ratio compares the endpoints in the acute and chronic toxicity studies 

with the daphnid and relates them to the acute toxicity endpoint to the saltwater mysid to predict 

the chronic endpoint for the saltwater mysid. The daphnia acute toxicity endpoint was 

determined to be 60.4 mg a.i/L classifying sulfentrazone as slightly toxic on an acute exposure 

basis (MRID 41911622). The chronic toxicity study with the daphnid determined the NOAEC 

to be 0.2 mg a.i./L (MRID 43588605), which suggests that sulfentrazone could potentially be 

300 times more toxic to daphnids on a chronic basis than on an acute basis. The acute endpoint 

for the saltwater mysid (Americamysis bahia) was determined to be 1.0 mg a.i/L (MRID 

43588603), classifying sulfentrazone as highly toxic to the mysid and making mysid shrimp 60 

times more sensitive than the daphnid on an acute basis. While it is common to have chronic 

endpoints much lower than acute endpoints and have significant differences in sensitivity 

between freshwater and marine/estuarine organisms, utilizing a factor of 300 introduces 

uncertainty for the chronic toxicity endpoint for the mysid. The low endpoint for the chronic 

mysid that was derived from the ACR resulted in an RQ exceedance. If the ACR underestimated 

the chronic mysid endpoint, it would overestimate the RQ which was estimated between 5 and 9 

depending on water clarity. 

Lack of registration in Florida.

The preliminary risk assessment presented a worse-case scenario for sulfentrazone use in 

Florida. EFED has confirmed that sulfentrazone is not registered or used in the entire state of 

Florida. Therefore, table 3 from the preliminary risk assessment has been corrected. 

Correction of Table 3. Application for registered use sites and the Apples proposed use of 

sulfentrazone.
12

Crop or 

NonAgricultural 

Use Site[1]

Single 

Min, lb 

ai/A 

product; 

All sites

Rates 

vary by 

soil 

texture / 

% 

Organic 

Matter

Max # 

Applic.

Aerial 

application? 

Minim. 

Interval 

(days)

PHI, 

days

Maxim. 

single 

(1st) 

aplica., 

lb ai/A

Maxim. 

Annual 

Rate, lb 

ai/A

Brassica 

leafy greens 0.07 Yes NS2 NS2 NS2 NS2 0.2 0.22

Corn (GMO 

tolerant to 

PPO 

herbicides)

0.094 Yes NS2 NS2 NS2 NS2 0.1875 0.375

Cowpeas, 

succulent 

(TN)

0.07 Yes NS2 NS2 NS2 NS2 0.1875 0.1875

Dry beans 

& peas (ND 

SD MT MN 

WY CO NE 

KS Wl Ml 

OR ID WA 

OR)

0.07 Yes NS2 NS2 NS2 NS2 0.25 0.25

Fallow, 

Postharvest

Burndown

0.094 Yes NS2 NS2 NS2 NS2 0.25 0.25

Horseradish 

((MN ND 

SD MT CO 

NE WY ID 

WA OR Wl 

Ml)

0.07 Yes NS2 NS2 NS2 NS2 0.25 0.25

Lima beans 

succul. (TN) 0.07 Yes NS2 NS2 NS2 NS2 0.1875 0.1875

Melons 0.09 No NS NS NS NS 0.25 0.25

Peanuts 

(AL, GA, 

MS, NC, 

SC, VA)

0.15 No NS NS NS NS 0.25 0.3

Potatoes 0.094 Yes NS Yes NS NS 0.25 0.25

Rhubarb 0.25 No 1 NS NA 46 0.25 0.25

Succulent 

Peas 0.07 Yes NS No NS NS 0.1875 0.1875

 
13

Crop or 

NonAgricultural 

Use Site[1]

Single 

Min, lb 

ai/A 

product; 

All sites

Rates 

vary by 

soil 

texture / 

% 

Organic 

Matter

Max # 

Applic.

Aerial 

application? 

Minim. 

Interval 

(days)

PHI, 

days

Maxim. 

single 

(1st) 

aplica., 

lb ai/A

Maxim. 

Annual 

Rate, lb 

ai/A

Sunflower 

subgroup 

20B

0.094 Yes NS Yes NS NS 0.25 0.25

Turnips 0.25 No 1 NS NA 3 0.25 0.25

Wheat -

spring (ID, 

OR, WA)

0.188 No NS NS NS ca. 120 0.1875 0.1875

Apples (new 

use) 0.125 No 2*[2] No 60 14 0.375 0.375

Asparagus 0.141 Yes NS NS NS 14 0.375 0.375

Berries 0.125 No 2 NS 60 3 0.375 0.375

Brassica 

head & stem 

(Broccoli, 

Cabbage

0.07 Yes NS NS NS NS 0.375 0.375

Cabbage 

transplante

d (MN ND 

SD MT CO 

NE WY ID 

WA OR Wl 

or Ml)

0.07 Yes NS NS NS NS 0.375 0.375

Citrus 0.125 No 2 NS 60 3 0.375 0.375

Flax (ND 

SD MT MN 

WY CO NE 

KS)

0.07 Yes NS NS NS NS 0.375 0.375

Fruiting 

veg. & Okra 

(except 

cucurbits)

0.07 Yes NS NS NS NS 0.375 0.375

Grapes 0.125 No 2 NS 60 3 0.375 0.375

Mint 0.141 Yes NS NS NS NS 0.375 0.375

 
14

Crop or 

NonAgricultural 

Use Site[1]

Single 

Min, lb 

ai/A 

product; 

All sites

Rates 

vary by 

soil 

texture / 

% 

Organic 

Matter

Max # 

Applic.

Aerial 

application? 

Minim. 

Interval 

(days)

PHI, 

days

Maxim. 

single 

(1st) 

aplica., 

lb ai/A

Maxim. 

Annual 

Rate, lb 

ai/A

Railroad, 

Highway, 

Roadside, 

Pipeline and 

Utility 

Rights-ofWay, 

Industrial 

Areas, 

Fence Rows, 

and Other 

listed Noncrop Sites

0.25 No 1 Yes* NA NS 0.375 0.375

Soybeans 0.141 Yes NS Yes NS NS 0.375 0.375

Strawberry 0.07 Yes NS NS NS NS 0.375 0.375

Sugarcane 0.141 Yes NS Yes NS 120 0.375 0.375

Tobacco 0.141 Yes NS NS NS NS 0.375 0.375

Tree nuts 0.125 No 2 NS 60 3 0.375 0.375

Turf: Sod 

Production, 

lawns, golf 

fairways 

and roughs

0.125 No NS NS NS 90 for sod 0.375 0.3750[3]

1[1] Limitations to crop strains or certain geographical areas (states) are given in parenthesis.

2 NS: Not specified

1[2] * = Implied, but not explicitly stated on product labels.

1[3] Implied; some labels need to be clarified regarding the maximum annual rate. The maximum 

annual use rate is 0.375 lb ai/A for turf (sod production, lawns, golf fairways and roughs).

 
15

Corrections of Table on Maximum Groundwater Concentrations from Prospective 

Groundwater Studies in the Preliminary Risk Assessment.

Some of the values for the Table 11 on page 39 of the preliminary risk assessmentwere for the 9-

foot depth lysimeter samples instead of the groundwater samples. This table should be replaced 

with the updated Table 11 provided below.

Table 11. Maximum observed concentrations of sulfentrazone and its acid degradate in shallow 

groundwater below or immediately downgradient of treated fields at four sites. Corrected values 

are bolded.

Chemical

NC1 

Site

IN1 

Site

IN2

Site

IN3 

Site

Concentration in ppb (days after initial application of obs.)

Sulfentrazone 37.4

(160d)

0.86 

(577d)

0.11

(153d)

0.09

(1149d)

3-Carboxylic Acid Sulfentrazone 11.4

(160d)

2.50 

(455d)

<0.1

(variable)

0.07

(753d)

SITE DESCRIPTIONS:

NC1 (>95th site ) = The test site was located near the town of Tarboro in Edgecombe County, North 

Carolina, and was located in a setting classified as very high vulnerability to groundwater 

contamination. Soil series = Tarboro sand to loamy sand. Sulfentrazone application rate = 0.50 lb 

ai/acre. (MRID 43345434 and 43926814). Average depth to groundwater = 9.2 feet. 

IN1(95th site) = The test site was located near the town of Leesburg in Kosciusko County, Indiana, and 

was located in a setting classified as 85th percentile in terms of vulnerability to groundwater 

contamination. Soil series = Tyner loamy sand to sandy loam. Sulfentrazone application rate = 0.17 lb 

ai/acre. Average depth to groundwater = 18.9 feet. (MRID 46816001). 

N2 (85th site = The test site was located near the town of Hanna in LaPorte County, Indiana, and was 

located in a setting classified as 95th percentile in terms of vulnerability to groundwater contamination. 

Soil series = Shipshe loamy sand to sandy loam. Sulfentrazone application rate = 0.22 to 0.44 lb 

ai/acre. Average depth to groundwater = 30 feet. (MRID 47453601).

N3 (75th site) = The test site was located near the town of La Porte in LaPorte County, Indiana, and 

was located in a setting classified as 75th percentile in terms of vulnerability to groundwater 

contamination. Soil series = Coupee silt loam. Sulfentrazone application rate = 0.22 lb ai/acre. Average 

depth to groundwater = 21 feet. (MRID 47453602).