Page 3 of 23

1.0 Executive Summary

HED has conducted an occupational and residential exposure assessment for the proposed use of

the herbicide ai

, topramezone

, on golf courses, sod farms and residential turfgrass

. Topramezone is currently registered for use on f ield, p op, s eed and s weet c o rn , as well as n on

- crop

o rnamentals, r ights

- of

- w ay, t ree p lantations, and o ther n on

- c rop a reas . There are currently no registered residential uses.

The proposed label allows for broadcast applications to golf courses and sod farms , but restricts

a pplicat ion s to residential turfgrass and athletic fields to spot spray only. The end

- use product is Topramezone 2.8 SC (EPA Reg # 7969

- xxx ), a 2.8 lb ai/gallon liquid formulation. The

maximum single application rate proposed is 2 fl oz/A (0. 044 lb ai/A) or 0.001 lb ai/1000 ft 2
(with a spray volume of 1 gallon per 1000 ft 2 )

.

Topramezone is a 4

- hydroxyphenylpyruvate dioxygenase ( HHPD ) inhibitor and t he effects observed following repeated oral exposures to topramezone are consistent with those expected

f rom HPPD inhibition in mammals. The primary target organs affected following topramezone administration were the eyes, thyroid, and pancreas. Points of departure (PODs) for the dermal

, inhalation , and incidental oral routes are based on effects seen in a two generation reproduction study with a no

- observed

- adverse

- effect leve l ( NOAEL ) of 0.4 mg/kg/day. Since an oral study

was selected for the short

- and i ntermediate

- term assessments, a 2.6 % dermal absorption factor was applied and i nhalation toxicity was assumed to be equivalent to oral toxicity. Exposures

from t he dermal and inhalation routes were combined because the PODs for the se routes are based on the same toxicological effects. HED’s level of concern (LOC) for topram e z one occupational and residential dermal

, inhalation and incidental oral exposures is 100 (i.e., a margin of exposure (MOE) less than 100 is considered by HED to be a risk of concern). The

LOC is based on 10X to account for interspecies extrapolation to huma ns from the animal test species and 10X to account for intraspecies sensitivity.

The residential handler assessment was completed assuming the maximum label application rate allowed for residential turfgrass and athletic fields. The proposed label only allows for spot

ap plications to residential sites; therefore, it was assumed that handheld equipment would be

used. The label states to use “low

- pressure sprayers”; therefore, backpack and manually

pressurized handwands were assessed for residential handlers. Dermal and i ncidental oral exposure scenarios were assessed for potential post

- application exposure from the use of

topramezone. A chemical

- specific turf transferable residue (TTR) study was available and was

used to estimate transferable residues from treated turf. Residential exposure scenarios are

considered to be short

- term only, due to the infrequent use patterns associated with homeowner products.

Residential handler dermal and inhalation risk estimates were calculated. For residential handlers, dermal and inhalation MOEs above 100 do not exceed HED’s LOC

. The combined dermal and inhalation exposure risks for mixer/loaders are not of concern (i.e., MOEs >100) at

baseline for all scenarios. Residential dermal and incidental oral post

- application risk estima tes

were also calculated. The combined MOEs are greater than 100 and are not of concern.Page 4 of 23

The occupational handler assessment was completed assuming the maximum label application rate. The proposed label allows for application by groundboom or by handheld equipment

. Based on the activity use pattern, the duration of exposure is e xpected to be short

- term (ST; 1 to 30 days ) and intermediate

- term (IT; 1 to 6 months ) for occupational scenarios; long

- term exposures (greater than 6 months) are not ant icipated based on the proposed use pattern. The same endpoints are used for short

- and intermediate

- term exposures; therefore

, risks are the same for all durations of exposure. The proposed label requires long

- sleeved shirt and long pants

, chemical

- resis tant gloves , shoes plus socks and goggles, face shield or safety glasses as dermal personal protective equipment ( PPE ) for all applicators and other handlers.

Occupational handler dermal and inhalation risk estimates were calculated. For occupational

h andlers, dermal and inhalation MOEs above 100 do not exceed HED’s LOC

. The combined

dermal and inhalation estimated risks are not of concern (i.e., MOEs >100) at baseline for all

scenarios. Occupational dermal post

- application risk estimates were calcula ted. The resulting MOEs are greater than 100 on day 0 (12 hours after application) for all activities. Since the post

application MOEs are not of concern, the restricted entry interval ( REI ) for topramezone is based on the acute toxicity categories. Top ramezone has low acute toxicity via the oral, dermal and inhalation routes of exposure (Toxicity category III or IV). It is a slight eye and dermal irritant (Toxicity category III and IV), but is not a dermal sensitizer. Therefore

, the Worker Protection Standard (WPS) interim REI of 12 hours is adequate to protect agricultural workers from post

application exposures to topramezone

.

Review of Human Research

This risk assessment relies in part on data from studies in which adult h uman subjects were intentionally exposed to a pesticide or other chemical. These data, which include studies from the Pesticide Handlers Exposure Database Version 1.1 (PHED 1.1); the Agricultural Handler Exposure Task Force (AHETF) database; the Outdoor R esidential Exposure Task Force (ORETF) database; and the Agricultural Re

- entry Task Force (ARTF) database are subject to ethics review pursuant to 40 CFR 26, have received that review, and are compliant with applicable ethics requirements. For certain stu dies that review may have included review by the Human Studies Review Board. Descriptions of data sources as well as guidance on their use can

be found at http://www.epa.gov/pe sticides/science/handler

- exposure

- data.html and http://www.epa.gov/pesticides/science/post

- app

- exposure

- data.html

.

2.0 Hazard Profile

Topramezone has low acute toxicity via the oral, dermal and inhalation routes of exposure (Toxicity category III or IV). It is a slight eye and dermal irritant (Toxicity category III and IV),

but is not a dermal sensitizer

. Table 2. 0. 1 presents a summary of the acut e toxicity information

for topramezone

.

Table 2.0.1 . Acute Toxicity Profile on Topramezone

. OPPTS Guideline Study Type Results Toxicity Category

870.1100 Acute oral toxicity / rat LD50 2000 mg/kg (males and females) III

870.1200 Acute dermal toxicity / rat LD50 2000 mg/kg (males and females) IIIPage 5 of 23

Table 2.0.1 . Acute Toxicity Profile on Topramezone

. OPPTS Guideline Study Type Results Toxicity Category

870.1300 Acute inhalation toxicity /

rat LC50 5.05 mg/L (males and females) IV

870.2400 Primary eye irritation /

rabbit Slight irritant III

870.2500 Primary dermal irritation /

rabbit Slight irritant IV

870.2600 Dermal sensitization / guinea pig Non

- Sensitizer

--

The effects observed following repeated oral exposures to topramezone are consistent with those expected from HPPD inhibition in mammals

. The primary target organs affected following topramezone administration were the eyes, thyroid, and pancreas. The most sensitive species was the rat and, at least in rats and dogs, males were more sensitive than females

. T he Cancer

Assessment Review Comm ittee ( CARC ) classified topramezone as “Not likely to be carcinogenic to humans at doses that do not alter rat thyroid hormone homeostasis.” The CARC determined that quantification of human cancer risk is not required since the NOAEL (0.4 mg/kg/day) for n on

- cancer risk assessment is not expected to alter thyroid hormone homeostasis nor result in thyroid tumor formation.

The short

- (1

- 30 days), and intermediate

- (1

- 6 months) term dermal , i nhalation and incidental

oral toxicological PODs were identified f rom a two generation reproduction study where the

effects were based on decreased body weight, body

- weight gain in males, increased thyroid and kidney weights of both sexes, and microscopic findings in eyes, kidney and thyroid of both

sexes . The NOAEL was 0.4 mg/kg /day . Since an oral study was used, a dermal absorption

factor of 2.6 % was used for the dermal risk assessment. Inhalation toxicity is assumed to be equivalent to oral toxicity. A summary of the toxicological endpoints and doses chosen for the relevant exposure scenarios for human risk assessment are found in Table 2

. 0. 2

.

Table 2.0.2 : Summary of Toxicology Endpoints and Point of Departure Doses for Topramezone in Dietary and

Residential Risk Assessment. Exposure

Scenario Point of Departure Uncertainty/ FQPA Safety Factors or LOC

for Risk Assessment Study and Toxicological Effects

Incidental Oral (Short

- and

Intermediate

- Term) NOAEL = 0.4

mg/kg/day Residential LOC for

MOE = 100 Two Generation Reproduction Study in Rats

Offspring LOAEL = 4.2 mg/kg/day based

decreases in b ody weights and body

- weight gains in the F2 generation offspring and increased time to preputial separation in the F1 male offspring

Short

- and

Intermediate

- Term,

Dermal Oral NOAEL= 0.4

mg/kg/day

(dermal

- absorption

factor = 2.6 %) Residential LOC for

MOE = 100 Two Generation Reproduction Study in Rats

Parental LOAEL = 4.2 mg/kg/day based on decreased body weight, body

- weight gain in males, increased thyroid and kidney weights of both sexes, and microscopic findings in eyes, kidney and thyroid of both sexes.

Short

- and

Intermediate

- Term Oral NOAEL= 0.4

mg/kg/day Residential LOC for

MOE = 100 Two Generation Reproduction Study in RatsPage 6 of 23

Table 2.0.2 : Summary of Toxicology Endpoints and Point of Departure Doses for Topramezone in Dietary and

Residential Risk Assessment. Exposure

Scenario Point of Departure Uncertainty/ FQPA Safety Factors or LOC

for Risk Assessment Study and Toxicological Effects

Inhalation (inhalation absorption

rate = 100%) Parental LOAEL = 4.2 mg/kg/day based on decreased body weight, body

- weight gain in males, increased thyroid and kidney weights of both sexes, and microscopic findings in eyes, kidney and thyroid of both sexes.

Cancer (Oral, dermal, inhalation) In accordance with the EPA Final Guidelines for Carcinogen Risk Assessment (March 29, 2005), the CARC classified topramezone as “Not likely to be carcinogenic to humans at doses that do not alter rat thyroid hormone homeostasis”. The CARC determined that the thyroid tumors arise through a non

- linear mode of action and the NOAEL (0.4 mg/kg/day) established for deriving the chronic Reference Dose (cRfD) is not expected to alter thyroid hormone homeostasis nor result in thyroid tumor formation.

P oint of Departure (POD) = A data point or an estimated point that is derived from observed dose

- response data and used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. NOAEL = no observed adver se effect level.

LOAEL = lowest o bserved adverse effect level. UF = uncertainty factor. UF A = extrapolation from animal to human (intraspecies). UF H = potential variation in sensitivity among members of the human population (interspecies). FQPA SF = FQPA Safety Factor. MOE = margin o f exposure. LOC = l evel of concern.

The Agency’s level of concern for risks (i.e., target level for M OEs ) is defined by the uncertainty factors that are applied to the assessment. The Agency applies a factor of 10X to account for interspecies extrapola tion to humans from the animal test species and another factor of 10X to

account for intra

- species sensitivity. HED has concluded that the FQPA safety factor for

topramezone can be reduced to 1 X for residential non

- dietary scenarios. The total uncertaint y factor that has been applied to occupational and residential risk assessments is 100 for short

- and

intermediate

- term dermal

, inhalation and incidental oral exposures.

3.0 Use Profile

Topramezone 2.8 SC (EPA Reg # 7969

- xxx ) is a 29.7 % ( 2.8 lb ai /gal) liquid formulation proposed for use on golf courses, sod farms and residential turfgrass

. The specific use sites listed on the label include: airports, athletic fields, cemeteries, golf courses, grounds or lawns around

residential and commercial es tablishments, houses of worship, military and other institutions, single/multifamily dwelling s , parks, picnic grounds, roadsides, schools, and sod farms.

The label allows for broadcast applications via ground equipment to golf courses and sod farms

. Ap plications to residential sites are limited to spot sprays using low

- pressure equipment, such as backpack and manually

- pressurized sprayers. The label prohibits application to golf course collars or greens, and application via chemigation or air

. The REI specified on the label is 12

hours. The use profile proposed for this Section 3 registration is summarized in Table 3

. 0. 1

.Page 7 of 23

Table 3. 0. 1

. Summary of Directions for Use of Topramezone

.

Application Equipment a Formulation

[EPA Reg. No.] Maximum

Application

Rate Max. No.

Applic.

per Year Maximum

Yearly Application

Rate (lb ai/A) Use Directions and Limitations

Golf Courses, Sod Farms, Residential Turfgrass

Groundboom applications

Soluble

concentrate [ 7969

- xxx ] 0.044 lb ai/A

2 0.089 REI = 12 hrs Application to residential turfgrass and athletic fields limited to spot sprays (i.e., handheld equipment) Do not apply to golf course collars or

greens Do not apply via chemigation or ai r If single application of topramezone does not provide complete cont rol, a sequential application can be made 2 to

3 weeks later Handheld equipment:

(1) Backpack

(2) Manually

pressurized

handwand

(3) Mechanically

pressurized handgun 0.001 lb

ai/1000 ft 2

(spray

volume: 1 gallon/1000

ft 2 )

a. Propose d label personal protective equipment : Applicators and all handlers must wear long

- sleeved shirt and long pants, chemical

- resistant gloves, shoes plus socks , goggles, face shield or safety glasses

.

4 .0 Occupational Exposure/Risk Characterization

4 .1 Short

- and Intermediate

- Term Handler Risk

Based on t he anticipated use patterns and current labeling

, types of equipment and techniques that can potentially be used

, occupational handler exposure is expected f rom the proposed uses. The quantitative expos ure/risk assessment develop ed for occupational handlers is based on the following scenarios :

(1) O pen mixing/loading liquids for groundboom application s ; ( 2 ) A pplying sprays via groundboom applications; ( 3 ) Mixing/loading / a ppl ying with a m anually

- pressurized handwand ; (4) Mixing/loading/applying with a mechanically

- pressurized handwand; and ( 5 ) Mixing/loading / a ppl ying with a backpack sprayer.

For pesticide handlers, HED presents estimates of dermal exposure for “baseline” (i.e., workers wearing a single layer of work clothing consisting of a long sleeved shirt, long pants, shoes plus socks and no protective gloves), as well as for “baseline” an d the use of protective gloves or other PPE, as might be necessary . The topramezone product labels direct mixers, loaders, applicators and other handlers to wear long

- sleeved shirt and long pants, chemical

- resistant gloves, shoes plus socks, goggles, face shield or safety glasses.

It is the policy of HED to use the best available data to assess handler exposure. Sources of generic handler data, used as surrogate data in the absence of chemical

- specific data, include thePage 8 of 23

PHED 1.1, the AHETF database, the ORETF database, or other registrant

- submitted occupational exposure studies. Some of these data are proprietary and subject to the data protection provisions of FIFRA. The standard values recommended for use in predicting handler exposure that are used i n this assessment, known as “unit exposures”, are outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (http://www.epa.gov/opp00001/science/handler

- exposure

- table.pdf), which, along with additional information on HED pol icy on use of surrogate data, including descriptions of the various sources, can be found at http://www.epa.gov/pesticides/science/handler

- exposure

data.html

.

Typically, HED completes short

- and intermediate

- term assessments for occupational scenarios in all cases because these kinds of exposures are likely and acceptable use/usage data are not available to justify deleting intermediate

- term scenarios. Based on use data and l abel instructions, HED believes that occupational exposures may occur over a single day or up to weeks at a time for many of the use

- patterns and that intermittent exposure over several weeks may also occur. Some applicators may apply these products over a period of weeks, because they are commercial applicators who are completing multiple pesticide applications for multiple clients. Long

- term exposures are not expected ; therefore, a long

- term assessment was not
conducted.

The daily areas treated and a mounts handled were defined for each handler scenario (in appropriate units) by determining the amount that can be reasonably treated by an individual in a single day. When possible, the assumptions for daily areas treated and amounts handled are taken from the HED’s ExpoSAC Policy #9: “Standard Values for Daily Acres Treated in Agriculture”, which was revised on July 5, 2000. Values used for a rea treated and amount

handled in each scenario include : 80 acres for groundboom application , 1000 ga llons for mechanically

- pressurized handgun, and 40 gallons for backpack and manually

- pressurized

handwand equipment

.

Since an oral study was selected for the short

- and intermediate

- term assessments, a 2.6 % dermal absorption factor was applied. In additi on, an assumption of equivalent toxicity from the oral and inhalation routes of exposure was made. A body weight of 80 kg was used. Daily dermal or inhalation handler exposures are estimated for each applicable handler task with the application rate, the amount handled or area treated in a day, and the applicable dermal or inhalation unit exposure using the following formula:

Daily Exposure = Unit Exposure x Application Rate x Daily Area Treated

Where:

Daily Exposure = Amount (mg/day) deposited on t he surface of the skin that is available for

dermal absorption or amount inhaled that is available for inhalation absorption; Unit Exposure = Unit exposure value (mg/lb ai) derived from August 1998 PHED data; Application Rate = Normalized applicatio n rate based on a logical unit treatment, such as acres (A);

and Daily Area Treated = Normalized application area based on a logical unit treatment such as acres (A/day).Page 9 of 23

The daily dermal or inhalation dose is calculated by normalizing the dai ly exposure by body weight and adjusting, if necessary, with an appropriate dermal or inhalation absorption factor using the following formula:

Average Daily Dose = Daily Exposure x Absorption Factor / Body Weight

Where:

Average Daily Dose = Absorbed dose received from exposure to a pesticide in a given scenario (mg/kg/day); Daily Exposure = Amount (mg/day) deposited on the surface of the skin that is available for

dermal absorption or amount inhaled that is available for inhalation absorption; Absorption Factor = A measure of the amount of chemical that crosses a biological boundary such as the skin or lungs (% of the total available absorbed); and Body Weight = Body weight determined to represent the population of interes t in a risk assessment (kg).

Dermal and inhalation risks were combined in this assessment, since the toxicological effects for these exposure routes were similar. Dermal and inhalation risks were combined using the following formula:

Total MOE = Point of Departure (mg/kg/day) / Combined dermal + inhalation dose (mg/kg/day)

Table 4 .1.1 presents the exposure/risks for short and intermediate

- term dermal and inhalation exposures at baseline. The combined derm al and inhalation exposure risk estimates are no t of concern (i.e., MOEs >100) at baseline for all scenarios

.Page 10 of 23

Table 4 .1.1. Short

- /Intermediate

- Term Occupational Exposure and Risk Estimates for Topramezone

. All estimates are at Baseline (i.e., no gloves/respirator).

Exposure Scenario Crop or Target Dermal Unit

Exposure ( u g/lb ai) 1 Inhalation

Unit Exposure ( u g/lb ai) 1 Application

Rate 2 Amount

Treated Daily 3 Dermal Inhalation Total

Baseline Baseline Dose (mg/kg/day) 4 MOE 5 Dose (mg/kg/day) 6 MOE 7 MOE 8

Mixer/Loader
Mixing/Loading Liquids

for Groundboom Applications Turf 220 0.219 0.044 lb

ai/A 80 A 0. 00 025 1,600 9. 6 x 10
- 6 42 ,000 1,500

Applicator
Applying Sprays via Groundboom Equipment Turf 78.6 0.34 0.044 lb

ai/A 80 A 0. 000 09 4,400 1.5 x 10

- 5 27 ,000 3,800

Mixer/Loader/Applicator

M i xing/Loading/Applying Liquids via Manually

pressurized Handwand Turf 100,000 30 0.001 lb ai/gallon 40

gallons 0.0013 310 1.5 x 10

- 5 27 ,000 300

Mixing/Loading/Applying Liquids via Backpack Sprayer Turf 8

, 260 2.58 0.001 lb ai/gallon 40

gallons 0.000 11 3,700 1.3 x 10
- 6 310,000 3,700

Mixing/Loading/Applying Liquids via Mechically

pressurized Handgun Turf 1,140 1.9 0.001 lb ai/gallon 1000

gallons 0.00 037 1,100 2.4 x 10
- 5 17,000 1,000

1 Based on “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (September 26, 2011); includes data from PHED/ORETF /AHETF (level of mitigation: Baseline and PPE (gloves ) )

. 2 Based on proposed label (Reg. No. # 7969

- xxx )

. 3 Exposure Science Advisory Council Policy #9.1

. 4 Dermal Do se = Dermal Unit Exposure (mg/lb ai ) x Application Rate (lb ai/acre or lb ai/gallon ) x Area Treated or Amount Handled (A/day or Gallons/day ) x DAF ( 2.6 %)/BW ( 80 kg)

. 5 Dermal MOE = Dermal NOAEL ( 0.4 mg/kg/day)/Dermal Dose (mg/kg/day)

. 6 Inhalation Dose = Inhalation Unit Exposure (mg/kg) x Application Rate (lb ai/acre or lb ai/gallon ) x Area Treated or Amount Handled (A/day or Gallons/day ) /BW ( 80 kg)

. 7 Inhalation MOE = Inhalation NOAEL ( 0.4 mg/kg/day)/ Inhalation Dose (mg/kg/day)

. 8 Total MOE = NOAEL (mg/kg/day)/Dermal Dose + Inhalation Dose

.Page 11 of 23

4 .2 Short

- and Intermediate

- Term Post

- Application Risk

HED uses the term post

- application to describe exposure s that occur when individuals are present in an environment that has been previously treated with a pesticide (also referred to as re

entry exposure). Such exposures may occur when workers enter previously treated areas to perform job functions, including activities related to crop production, such as scouting for pests or harvesting.

4 .2.1 Dermal Post

- Application Risk

In the case of topramezone , there is a potential for post

- application dermal exposure to workers following foliar applications of topramezone to golf courses and sod farms

. It is the policy of

HED to use the best available data to assess post

- application exposure. Sources of generic post

application data, used as surrogate data in the absence of chemical

- specific data

, are derived

from Agricultural Reentry Task Force (ARTF) exposure monitoring studies, and , as proprietary data, are subject to the data protection provisions of FIFRA. The standard values recommended for use in predicting post

- application exposure that are used in thi s assessment, known as “transfer coefficients”, are presented in the “Science Advisory Council for Exposure (ExpoSAC) Policy 3” (http://www.epa.gov/pesticides/science/exposac_policy3.pdf), which, along with additional information about the ARTF data, can be found at http://www.epa.gov/pesticides/science/post

- app

- exposure

- data.html

. Table 4.2.1.1 provides a summary of the transfer coefficients and activities associated with go lf course and sod farm turf.

Table 4.2.1.1. Post

- application Activities and Dermal Transfer Coefficients

. Proposed Use Site Transfer Coefficients (cm 2 /hr) Activities

Turf 3,700 golf course maintenance

6,700 harvesting, maintenance, transplanting

In addition, the following assumptions and data were used in the topramezone dermal post

application assessment :

• Application Rate = 0.044 lb ai/A

• Exposure Duration = 8 hours per day

• Body Weight = 80 kg

• Dermal absorption = 2.6%

• Chemical

- specific TTR data submitted in support of the proposed turf uses (MRID

48379401 )

.

Summary of the TTR Study: Determination of Transferable Residues of Topramezone

Turf Treated with BAS 670 01 H ( MRID 48379401 )

This study was designed to determine the transferable turf residue (TTR) of topramezone dislodged from turf at three field trial sites in Pennsylvania, California, and Washington. Three separate plots were set up at each study site: (1) Plot #1 acted as a control plot, (2) Plot #2Page 12 of 23

received 3 applications for an average total application rate of 0.088 lb ai/A and (3) Plot #3 received 1 application for an average total application rate of 0.046 lb ai/A. The re

- treatment interval for Plot #2 at each site was approximately 21 days. Applications were made with

groun dboom equipment at the Washington and California sites and with a backpack sprayer equipped with a 3

- gallon stainless tank and a hand

- held boom at the Pennsylvania site. The Modified California Roller technique was used to evaluate the amount of transfera ble residues from turf grass.

First

- order dissipation kinetics were assumed to generate dissipation curves for topramezone. The individual data points (rather than averages) were included in the analysis for each site from the day of application up until the point where residues were less than the level of quantitation (LOQ). A separate analysis was performed for each site as well as a combined analysis of all the sites for the two different application regimes (plot #2 versus plot #3).

For the plots that received 3 applications (plot #2 from each site), the highest average measured TTR values were 0.0015 μg/cm 2 (occurring immediately after the 2 nd application), 0.0011 μg/cm 2 (occurring 4 hours after the 3 rd application), and 0.0011 μg/cm 2 (occurring immediately

after the 2 nd application) for the PA, WA, and CA sites, respectively. At all sites, residue levels declined to <LOQ by day 4 or 5 after the last application.

For plots that received 1 application (plot #3 from each site), the hig hest average measured TTR values were 0.0018 μg/cm 2 (occurring immediately after the application), 0.0016 μg/cm 2
(occurring 4 hours after the application), and 0.0014 μg/cm 2 (occurring immediately after the application) for the PA, WA, and CA sites, respec tively. At all sites, residue levels declined to <LOQ by day 4 or 5 after the application.

Based on the results from the plots that received 3 applications (plot #2 from each site), the half

life of topramezone on turf was determined to be 1.16 days (R 2

= 0.929), 1.43 days (R 2 =0.930), and 0.947 days (R 2 =0.932) for the PA, WA, and CA test sites, respectively. When the data were combined for the three sites for plot #2, the half

- life of topramezone on turf was determined to be 1.14 days (R 2 =0.899). Based on t he results from the plots that received 1 application (plot #3 from each site), the half

- life of topramezone on turf was determined to be 1.06 days (R 2 =0.787), 0.855 days (R 2 =0.864), and 0.874 days (R 2 =0.953) for the PA, WA, and CA test sites, respectively . When the data were combined for the three sites for plot #3, the half

- life of topramezone on turf was determined to be 0.899 days (R 2 =0.865).

There were some quality control issues noted with regard to the field fortification samples and

recoveries. A verage field fortification recoveries were not in the acceptable range of 70 to 120%. Individual recoveries ranged from 40 to 87% and average recoveries ranged from 49 to 73%. In addition, the field fortification levels did not bracket the topramezone TTR values found on cloth dosimeters. The field fortification levels were 25 and 250 μg/sample. Field sample TTRs were all lower than the lowest field fortification level. Field sample TTRs ranged from 1.14 to 6.70 μg/sample. Fortified samples were analyzed ; however, at levels close to the field samples during the method validation procedure. Method validation was performed prior to the start of the study and included an analysis of five replicates fortified with topramezone at the method LOQ (1 μg/sample) and five replicates fortified at a higher level (250 μg/sample).Page 13 of 23

Recoveries ranged from 67 to 87%, with an overall average recovery of 80%. Concurrent laboratory recoveries of topramezone ranged from 67 to 115%, averaging 88% (n=46). In addition, a free zer storage stability study was performed, where fortified cloth storage stability samples spiked at 25 μg/sample were analyzed after 45, 90 and 176 days of frozen storage. Recoveries ranged from 72 to 96% (n=6).

Even though the field fortification reco veries were not all within the acceptable range outlined in the study guidelines, taking into consideration all of the quality control information provided, the results of this study are still considered acceptable for risk assessment purposes.

Summary of TTR Values and Regression Analysis Results for Turf Treated with 3 Applications of Topramezone (MRID# 48379401). Input/Parameter Pennsylvania Washington California Combined

Application Rate (lb ai/A)

Application Equipment Average single application: 0.029

Total rate: 0. 088

Backpack sprayer equipped with

a 3

- gallon stainless tank and a

hand

- held boom Average single application: 0.030

Total rate: 0. 0 90

Groundboom Average single

application rate: 0.029

Total rate: 0. 0 87

Groundboom

Spray volume (GPA) 86.0 to 88.9 86.0 to 88.9 86.0 to 88.9

Measured Average Day 0 Residue (μg/cm 2 ) 0.0007 (first application)

0.0015 (second application)

0.0012 (third application) 0.0010 (first application)

0.0008 (second application)

0.0010 (third application) 0.0007 (first application)

0.0011 (second application)

0.0009 (third application) 0.0010 (third application)

Predicted Day 0

Residue (μg/cm 2 ) a 0.0011 0.0012 0.0009 0.0011

Slope

- 0.599

- 0.484

- 0.732

- 0.607

Half

- life (days) 1.16 1.43 0.947 1.14

R 2 0.929 0.930 0.936 0.899

a. Regression data is based on TTRs collected after the third (last) application.

Summary of TTR Values and Regression Analysis Results for Turf Treated with 1 Application of Topramezone (MRID# 48379401). Input/Parameter Pennsylvania Washington California Combined

Application Rate (lb ai/A)

Application Equipment Total rate: 0.047

Backpack sprayer equipped with a 3

- gallon stainless tank

and a hand

- held boom Total rate: 0.045

Groundboom Total rate: 0.045

Groundboom

Spray volume (GPA) 85.1 to 89.0 85.1 to 89.0 85.1 to 89.0

Measured Average Day 0 (μg/cm 2 ) 0.0018 0.0013 0.0014 0.0015

Predicted Day 0 (μg/cm 2 ) 0.0020 0.0020 0.0015 0.0019

Slope

- 0.654

- 0.811

- 0.793

- 0.771

Half

- life (days) 1.06 0.855 0.874 0.899

R 2 0.787 0.864 0.953 0.865Page 14 of 23

The proposed use profile allows for a maximum of two applications, with the second application occurring 2 to 3 weeks after the first (if needed). Since this use pattern does not match either of the two approaches used in the study, the predicted TTR valu e on Day 0 based on the combined

data from the plots from each site that received one application was chosen (0.0019 ug/cm 2 ). This value is the highest TTR value reported for the study and is considered health protective for the proposed use.

The following equations were used to calculate risks for workers performing post

- application

activities :

Dermal Daily Dose t = [TTR t (μg/cm 2 ) x 0.001 mg/μg x TC (cm 2 /hr) x ET (hrs) x DAF ]/BW (kg)

Where:

t = number of days after application day (days);

TTR t = turf transferable residue on day "t" (ug/cm 2 );

TC = transfer coefficient (cm 2 /hr);

ET = exposure time (hr/day); and,

BW = body weight (kg).

MOE= Dermal NOAEL (mg/kg/day)/Dermal Daily Dose (mg/kg/day)

Post

- application dermal exposure and risk estima te s for workers conducting activities on golf

course s and sod farms resulted in MOE s greater than the LOC of 100 and

, therefore

, are not of concern. A summary of the post

- application exposure and risk estimate s from use of

topramezone is provided in Table 4.1.2.2

.

Table 4.1.2.2 . Summary of Short

- and Intermediate

- term Occupational/Commercial Post

- application Risks for Topramezone.

Crop/Site Activities Transfer

Coefficient (cm 2 /hr) Application

Rate (lb ai/A) TTR 1

(ug/cm 2 ) Day 0

MOE 2 Day X at

which
MOE ≥

LOC

Turf golf course maintenance 3,700

0.044 0.0019 23,000 0 harvesting, maintenance, transplanting 6,700 13,000 0

1. TTR value is from chemical

- specific turf transferable residue study ( MRID 48379401 ) 2. MOE = POD (NOAEL, 0.4 mg/kg/day) / Daily Dermal Dose. Daily Dermal Dose = [ TT R (μg/cm 2 ) x TC x 0.001 mg/μg x 8 hrs/day x 2.6 % dermal absorption] body weight ( 80 kg adult )

.

REI

Short

- and intermediate

- term post

- application risks were not a concern on day 0 (12 hours following application) for all post

- application activities . Therefore, the REI is based on the acute toxicity of topramezone

. Topramezone has low acute toxicity via the oral, dermal and inhalation routes of exposure (Toxicity category III or IV). It is a slight eye and dermal irritant (Toxicity category III and IV), but is not a dermal sensitizer. Therefore

, the WPS interim REI of 12 hours is adequate to protect agricultural workers from post

- application exposures to topramezone

.Page 15 of 23

4 .2.2 Inhalation Post

- Application Risk

Based on the Agency's current practices, a quantitative occupational post

- application inhalation exposure assessment was not performed for topramezone at this time. However, there are multiple potential sources of post

- application inhalation exposure to individuals performing post

application activities in previously treated fields. These potential sources include volatilization of pesticides and resuspe nsion of dusts and/or particulates that contain pesticides. The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in Decembe r 2009. The Agency received the SAP’s final report on March 2, 2010 ( http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html ). The Agency is in the process of evaluating the SAP report as well as available post

- application inhalation exposure

dat a generated by the Agricultural Reentry Task Force and may, as appropriate, develop policies and procedures, to identify the need for and, subsequently, the way to incorporate occupational

post

- application inhalation exposure into the Agency's risk assessm ents. If new policies or procedures are put into place, the Agency may revisit the need for a quantitative occupational

post

- application inhalation exposure assessment for topramezone

.

5 .0 Residential (Non

- Occupational) Exposure/Risk Characterization

Since the product can be applied to residential turf sites, exposure and risk estimates were

calculated for both residential handlers and for post

- application activities associated with residential turfgrass and golf courses.

5 .1 Residential Handler Exp osure and Risk

The r esident ial handler exposure assessment estimate s dermal and inhalation exposures for individuals using topramezone on residential turfgrass

. The following are key differences between residential and occupational handler assessments:

Residential handler exposure scenarios are considered to be short

- term only, due to the infrequent use patterns associated with homeowner products.

A tiered approach for personal protection using increasing levels of PPE is not used in

residential hand ler risk assessments. Homeowner handler assessments are based on the assumption that individuals are wearing shorts, short

- sleeved shirts, socks, and shoes.

Homeowner handlers are expected to complete all tasks associated with the use of a pesticide prod uct including mixing/loading if needed as well as the application.

The quantitative exposure/risk assessment developed for residential handlers is based on the following scenarios:

(1) Mixing/Loading/Applying Liquids with Backpack Sprayer

, and (2) Mixing/Loading/Applying Liquids with Manually

- pressurized Handwand.Page 16 of 23

Unit exposure values and estimates for area treated were taken from the Health Effects

Division’s 201 2 Standard Operating Procedures for Residential Pesticide Exposure Assessment : Lawns/ Turf

.

Handler dermal and/or inhalation exposures are estimated by multiplying the application

method

- specific unit exposure by an estimate of the amount of active ingredient handled in a day, using the following algorithm:

where :
E = exposure (mg/day);

UE = unit exposure (mg/lb ai);

AR = application rate (e.g., lb ai/ft 2 , lb ai/gal); and

A = area treated or amount handled (e.g., ft 2 /day, gal/day).

Dermal and/or inhalation doses are estimated using the following algorithm:

where:

D = dose rate (mg/kg

- day);

AF = absorption factor (dermal and/or inhalation); and

BW = body weight (kg).

Dermal and inhalation risks were combined in this assessment, since the toxicological effects for these exposure routes were similar. Dermal and inhalation risks were combined using the following formula:

Total MOE = Point of Departure (mg/kg/day) / Combined dermal + inhalation dose (mg/kg/day)

Short

- term risks for residential handlers are present ed in Table 5.1.1 . Intermediate

- term exposures are not likely because of the intermittent nature of applications by homeowners.

Short

- term combined dermal plus inhalation risk estimates to residential handlers do not exceed

HED’s level of concern for all scenarios.

Table 5.1.1 . Reside ntial Handler Exposure and Risk Estimates for Topramezone Applications to Turfgrass

.

Exposure Scenario Application Rate (lb ai/gallon ) a Area

Treated Daily ( gallons ) b Baseline Unit

Exposures b (mg/lb ai) Baseline Dose d
(mg/kg/day) Baseline MOE e Combined MOE f

Dermal c Inhalation c Dermal Inhalation Dermal Inhalation Dermal + Inhalation

Mixer/Loader/Applicator Mixing/Loading/Applying Liquids with Manually

pressurized Handwand 0.001 5 63 0.018 0.000 1 1.1 x 10

- 6 3,900 3 6 0,000 3,900Page 17 of 23

Table 5.1.1 . Reside ntial Handler Exposure and Risk Estimates for Topramezone Applications to Turfgrass

.

Exposure Scenario Application Rate (lb ai/gallon ) a Area

Treated Daily ( gallons ) b Baseline Unit

Exposures b (mg/lb ai) Baseline Dose d
(mg/kg/day) Baseline MOE e Combined MOE f

Dermal c Inhalation c Dermal Inhalation Dermal Inhalation Dermal + Inhalation

Mixing/Loading/Applying Liquids with Backpack Sprayer 0.001 5 130 0. 14 0.00 021 8.8 x 10

- 6 1,900 4 6 ,000 1,800

a

. Application r ates based on proposed label for topramezone (Topramezone 2.8 SC, EPA Reg#7969

- xxx).

b. Based on HED ’s Standard Operating Procedures for Residential Pesticide Exposure Assessment ; Lawns/Turf ( January 2012 ).

c

. Baseline Dermal: Long

- sleeve shirt, long pants, and no gloves; Baseline Inhalation: no respirator.

d

. Dose (mg/kg/day) = daily unit exposure (mg/ lb ai) x application rate ( lb ai/gal ) x gal treated * absorption factor (dermal = 2.6 %) / body weight ( 80 kg).

e

. MOE = NOAEL ( 0.4 mg/kg/day) / daily dose (mg/ kg/ day). Level of concern = 100.

f

. Combined MOE = NOAEL ( 0.4 mg/kg/day ) / combined dermal + inhalation dose (mg/kg/day)

.

5 .2 Residential Post

- application Exposure and Risk

Topramezone can be used in many areas that can be frequented by the general population including residential areas (e.g., home lawns). As a result, individuals can be exposed by entering these areas if they have been previously treated.

5 .2.1 Post

- application Inh alation

Based on the Agency's current practices, a quantitative post

- application inhalation exposure assessment was not performed for topramezone at this time . However, volatilization of pesticides may be a potential source of post

- application inhalation exposure to individuals nearby to pesticide applications. The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel (SAP) in December 2009. The Agency received the SAP’s final report on March 2, 2010 ( http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html ). The Agency is in the process of evaluating the SAP report and may, as appropriate, developing policies and proce dures, to identifying the need for and, subsequently, the way to incorporate

post

- application inhalation exposure into the Agency's risk assessments. If new policies or procedures are put into place, the Agency may revisit the need for a quantitative post

- application inhalation exposure assessment for topramezone

.

5 .2.2 Post

- application Dermal and Incidental Oral

Short

- term dermal and incidental oral exposure and risk estimate s have been assessed here and

since the short

- and intermediate

- term PODs are the same, the short

- term assessment is protective of longer

- term exposures. However, in the case of incidental soil ingestion, HED has conducted a conservative assessment of potential intermediate

- term oral risk from soil ingestion by using a yearly application rate of 0.089 lb ai/A, instead of the maximum single rate of 0.044 lb ai/A, to address the persistence [half life of ≥ 240 days ( J. Hetrick, D 388368

, 11/14 /201 1 ) ] and likely potential build

- up of topramezone in the soil.

The scenarios, routes of exposure and lifestages assessed include:

Physical activities on turf: adults (dermal) and children 1 < 2 years old (dermal andPage 18 of 23

incidental oral); Mowing: adults (dermal) and children 11 < 16 years old (dermal); and Golfing: adults (dermal) , ch ildren 11 < 16 years old (dermal) , and children 6 < 11 years

old (dermal).

The following equations and assumptions were used to calculate post

- application risk estimates :

Dermal exposure :

E = TTRt * CF1 * TC * ET

where :
E = exposure (mg/day);

TTRt = turf transferable residue on day "t" (μg/cm 2 );

CF1 = weight unit conversion factor (0.001 mg/μg);

TC = transfer coefficient (cm 2 /hr); and

ET = exposure time (hr/day).

Assumptions:

TTR value is based on chemical

- specific study; assumed to be 0. 0019 ug/cm 2 based on predicted day 0 residue value calculated by a first

- order dissipation kinetics and decay

model. A summary of the TTR study is presented in the occupational post

- application

section of this document.

T ransfer coefficient s:

o Physical activities on turf: 180,000 cm 2 /hr for adults and 49,000 cm 2 /hr for children 1 < 2 years old

o Mowing: 5,500 cm 2 /hr for adults and 4,500 cm 2 /hr for children 11 < 16 years old

o Golfing: 5,300 cm 2 /hr for adults, 4,400 cm 2 /hr for children 11 < 16 years old, and 2,900 cm 2 / hr for children 6 < 11 years old Exposure time (hr):

o Physical activities on turf: 1.5 hr for adults and children

o Mowing: 1 hr

o Golfing: 4 hr

Hand

- to

- Mouth:

E = [HR * ( F M * SA H ) * (ET * N_Replen) * (1

- (1

- SE ) (Freq_Replen/N

- Replen) )]

where:

E = exposure (mg/day);

HR = hand residue loading (mg/cm 2 );

F M = fraction hand surface area mouthed / event ( 0.127 /event);

SA H = typical surface area of one hand ( 150 cm 2 );

ET = exposure time ( 1.5 hr /day); N_Replen = number of replenishment intervals per hour ( 4 intervals/hour);Page 19 of 23

SE = saliva extraction factor ( 0.5 ); and Freq_Replen = number of hand

- to

- mouth contacts events per hour ( 13.9 events/hour).

and

where:

HR = hand residue loading (mg/cm 2 );

Fai hands = fraction ai on hands compared to total surface residue from dermal

transfer coefficient study ( 0.06) ;
DE = dermal exposure (mg); and

SA H = typical surface area of one hand ( 150 cm 2 ).

Object

- to

- Mouth:

E = [OR* CF1 * SAM O * (ET * N_Replen) * (1

- (1

- SE O ) (Freq_Replen/N_Replen) )]

where:

E = exposure (mg/day);

OR = chemical residue loading on the object on day “t” (ug/cm 2 );

CF1 = weight unit conversion factor (0.001 mg/μg);

SAM O = area of the object surface that is mouthed ( 10 cm 2 /event);

ET = exposure time ( 1.5 hr/day); N_Replen = number of replenishment intervals per hour ( 4 intervals/hour);

SE = saliva extraction factor ( 0.5 ); and Freq_Replen = number of object

- to

- mouth contact events per hour ( 8.8 events/hour).

and

OR = AR * F O * CF2 * CF3

where:

OR = chemical residue loading on the object (μg/cm 2 );

AR = application rate ( 0.044 lb ai/acre );

F O = fraction of residue available on the object ( 0.01 );

CF2 = weight unit conversion factor (4.54 x 10 8 μg/lb); and

CF3 = area unit conversion factor (1.08 x 10 - 3 ft 2 /cm 2 or 2.47 x 10 - 8

acre/cm 2 ).

Soil ingestion:

E = SRt * SIgR * CF1Page 20 of 23

where:

E = exposure (mg/day);

SRt = soil residue on day "t" (μg/g); SIgR = ingestion rate of soil ( 50 mg/day); and

CF1 = weight unit conversion factor (1 x 10 - 6 g/μg).

and

SRt = AR * FS * (1

- F D ) t * CF2 * CF3 * CF4

where:

SRt = soil residue on day "t" (μg/g);

AR = application rate ( 0.044 lb ai/acre for short

- term and 0.089 lb ai/acre for

intermediate

- term );

FS = fraction of ai available in uppermost cm of soil ( 1.0 /cm);

F D = fraction of residue that dissipates daily ( 0.1 );

t = post

- application day on which exposure is being assessed (0) ; CF2 = weight unit conversion factor (4.54 x 10 8 μg/lb);

CF3 = area unit conversion factor (1.08 x 10 - 3 ft 2 /cm 2 or 2.47 x 10 - 8 acre/cm 2 ); a nd

CF4 = soil volume to weight unit conversion factor (0.67 cm 3 /g soil).

For each scenario, absorbed dose (normalized to body weight) was calculated as:

where :
D = dose (mg/kg

- day);

E = exposure (mg/day);

AF = absorption factor (dermal only ; 13% ); and

BW = body weight ( 80 kg for adults; 57 kg for children 11 < 16 years old, 32 kg for children 6 < 11 years old, 11 kg for children 1 < 2 years old ).

Dermal and incidental oral risk estimate s were calculated using the following formula:

MOE = Point of Departure (mg/kg/day) / Dermal or incidental oral dose (mg/kg/day)

where :
D ermal NOAEL = 0.4 mg/kg/day, and Incidental oral NOAEL = 0.4 mg/kg/day

Table 5 .2 .2.1 presents the post

- appli cation dermal and incidental oral MOE values calculated for the appropriate lifestages after applications of topramezone to turf

. Since the toxicological effects are similar for dermal versus incidental oral PODs, dermal risks were combined with

incidenta l oral risks for children 1 < 2 years old

. Post

- application risk estimates do not exceedPage 21 of 23

HED’s level of concern for any of the scenarios assessed.

Table 5 .2.2.1. Short

- Term Residential Post

- application Exposure and Risk Estimates for Topramezone

. Lifestage Post

- application Exposure Scenario Dose (mg/kg/day) MOEs

Adult

Turf

-

sprays Dermal Physical Activities on Turf 0.0008 3 480
Mowing 1.7 x 10
- 5 2 4 ,000
Golfing 6.6 x 10
- 5 6,100

Child 11 < 16 years old Dermal Mowing 2.0 x 10
- 5 2 1 ,000
Golfing 7. 6 x 10
- 5 5,200
Child 6 < 11 years old Dermal Golfing 9.0 x 10
- 5 4, 5 00

Child 1 < 2 year old Dermal Physical Activities on Turf 0.001 7 2 4 0

Hand to Mouth 0.0002 6 1, 5 00
Object to Mouth 2. 1 x 10
- 5 19 ,000

Short

- term Incidental Soil Ingestion 1. 5 x 10
- 6 2 7 0,000

Intermediate

- term Incidental Soil Ingestion 3.0 x 10
- 6 1 3 0,000

5.3 Combined Exposure

HED combines risk estimates resulting from separate post

- application exposure scenarios when it is likely they can occur simultaneously based on the use pattern and the behavior associated with the exposed population and when the toxicological effects are similar. For topramezone, the toxicological effects are s imilar for the dermal, inhalation and incidental oral routes; therefore, the exposures via these routes were combined where appropriate. For residential handlers, dermal and inhalation exposures were combined. For post

- application scenarios, dermal and

i ncidental oral exposures were combined for children 1 < 2 years old.

The incidental oral scenarios (i.e., hand

- to

- mouth, object

- to

- mouth, and soil ingestion) should be

considered inter

- related and it is likely that they occur interspersed amongst each other across

time. Combining all three of these scenarios with the dermal exposure scenario would be overly

conservative because of the conservative nature of e ach individual assessment. Therefore , the

post

- application exposure scenarios that were combined for children 1 < 2 years old are the

dermal and hand

- to

- mouth scenarios. This combination should be considered a protective estimate of children’s exposure t o pesticides used on turf.Page 22 of 23

Table 5.3.1. Short

- and Intermediate

- Term Residential Exposures for the Topramezone Combined Residential Risk Calculations.

Population Handler Exposure (mg/kg/day) 1 Residential

Handler Total Exposure (mg/kg/day) 3 Residential

H andler

Total MOE Post

- application Exposure (mg/kg/day) 2 Residential

Post

application Total Exposure (mg/kg/day) 3 Residential

Post

application

Total MOE Dermal Inhalation Dermal Inhalation Oral

Short

- Term

Adult Male 0.00 021 8.8 x 10 - 6 0.00 022 1,800 0.0008 3 N/A N/A 0.0008 3 480 Child 11 < 16 years old N/A 7. 6 x 10 - 5 N/A N/A 7. 6 x 10 - 5 5,200 Child 6 < 11 years old N/A 9.0 x 10 - 5 N/A N/A 9.0 x 10 - 5 4,500 Child 1 < 2 years old N/A 0.001 7 N/A 0.0002 6 0.0019 210

Intermediate

- Term Child 1 < 2 years old N/A N/A N/A 3.0 x 10 - 6 3.0 x 10 - 6 130,000

1 Handler exposure represents high end inhalation handler exposure, where the exposure duration is appropriate to assess

. 2 Postapplication exposure represents high end incidental oral exposure for the relevant exposure duration

. 3 F or adults, r esidential total exposure combines the highest dermal and inhalation exposures (Table 4.2.2.1 ), where applicable. For young children, total residential exposure combines high end post application incidental oral AND derma l exposure, where applicable (Table 5.2.2.1 ).Page 23 of 23

5.4 Residential Bystander Post

- application Inhalation Language

Based on the Agency's current practices, a quantitative post

- application inhalation exposure assessment was not performed for topramezone at this time. However, volatilization of pesticides may be a source of post

- application inhalation exposure to indivi duals nearby pesticide applications. The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009, and received th e SAP’s final report on March 2, 2010 ( http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html ). The Agency is in the process of evaluating the SAP report and may, as appropriate, develop policies and procedures to identify the need for and, subsequently, the way to incorporate post

application inhalation exposure into the Agency's risk assessment s. If new policies or procedures are developed, the Agency may revisit the need for a quantitative post

- application inhalation exposure assessment for topramezone.

5.5 Spray Drift

Spray drift is always a potential source of exposure to residents nearby to spraying operations. This is particularly the case with aerial application, but, to a lesser extent, could also be a potential source of exposure from the ground application method employed for topramezone

. The Agency has been working with the Spray D rift Task Force, EPA Regional Offices and State Lead Agencies for pesticide regulation and other parties to develop the best spray drift management practices (see the Agency’s Spray Drift website for more information at http://www.epa.gov/opp00001/factshee ts/spraydrift.htm). On a chemical by chemical basis, the Agency is now requiring interim mitigation measures for aerial applications that must be placed on product labels/labeling. The Agency has completed its evaluation of the new database submitted by the Spray Drift Task Force, a membership of U.S. pesticide registrants, and is developing a policy on how to appropriately apply the data and the AgDRIFT computer model to its risk assessments for pesticides applied by air, orchard airblast and ground hydr aulic methods. After the policy is in place, the Agency may impose further refinements in spray drift management practices to reduce off

- target drift with specific products with significant risks

associated with drift.