UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

DA TE: September 10, 2015 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

SUBJ ECT: Primisulfuron-Methyl. Human Health Draft Risk Assessment for Registration 

Review. 

PC Code: 128973 

Decision No.: 499855 

Pelilion No.: NA 

DP Barcode: 0 425535 

Registration Nos.: Various 

Regula tory Action: Registration Review 

Risk Assessment Type: Single Chemica l/Aggregate Case No.: NA 

TXR No.: NA CAS No.: 86209-5 1-0 

M RID No.: NA .tO CFR: § 180.452 

FROM: S

Juli

ha

e 

lu 

Van 

Shelat

Alstine

, Indu

, 

st

Environmental 

rial Hygienist 

Hea

S?J;ltl ~ 

cientist 

Christopher Schlosser, Toxicologist 

Risk Assessment Branch VI 

Health Effects Division (7509P) 

THRO UGH: Donna S. Davis, Acting Branch Chief 

Risk Assessment Branch VI 

TO: 

Hea lth Effects Division (7509P) 

Christina Scheltcma, Chemical Review Manager 

Kelly Sherman. Acting Branch Chief 

Risk Management and Implementatio n Branch 3 

Pesticide Re-Registration Division (7508P) 

Primisulfuron-methyl is a systemic herbi cide belonging to the sulfonylurea group of herbicides. 

The mechanism of action is the inhibition of amino acid synthesis in plants through inhibition of 

acetolactate synthase (ALS). This document eva luates the existing uses of primisulfuron-methyl 

as part of Registration Review and represents the draft risk assessment (ORA). The Agency is 

reviewing all the sulfonylurea herbicides jointly under Registration Review. 

Since the last human health risk assessment (W. Hazel, D280923, 6/28/2002) and scoping 

document (M. Sahafeyan, 0 394824, 3/7/20 12), the following updates have been incorporated for 

primisulfuron- methyl. 

• A screening-level estimated drinking water concentration (EDWC) value was used to 

assess primisulfuron-methyl dietary exposure and risk. 

• Toxicological endpoints and points of departure (PODs) u:iedfor risk assessment have 

been updated to reflect current policies. 

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Primisulfuron-methyl 0425535 

• The occupational risk assessment has been updated to incorporate new science policies. 

• A spray drift assessment was completed as part of Registration Review. 

Page 2 of 34 
Primisulfuron-methyl D425535

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Table of Contents

1.0 Executive Summary............................................................................................................. 4

2.0 HED Recommendations ...................................................................................................... 4

2.1 Tolerance Considerations................................................................................................. 4

2.2 Data Deficiencies ............................................................................................................. 4

3.0 Introduction.......................................................................................................................... 4

3.1 Use Profile & Anticipated Exposure Pathways................................................................ 4

3.2 Consideration of Environmental Justice .......................................................................... 6

4.0 Hazard Identification/Toxicology........................................................................................ 7

4.1 Summary of Toxicological Effects....................................................................................... 7

4.2 Safety Factor for Infants and Children (FQPA Safety Factor) ............................................. 8

4.3 Toxicity Endpoint and Point of Departure Selections .......................................................... 8

4.4 Endocrine Disruptor Screening Program ......................................................................... 9

5.0 Residue Chemistry............................................................................................................. 10

6.0 Dietary Risk Assessment ................................................................................................... 10

6.1 Water Residue Profile .................................................................................................... 11

6.2 Dietary (Food + Water) Exposure Assessment.............................................................. 11

7.0 Residential (Non-Occupational) Exposure/Risk Characterization .................................... 12

8.0 Non-Occupational Spray Drift Exposure and Risk Estimates........................................... 12

8.1 Risk Estimates from Lawn Deposition Adjacent to Applications.................................. 12

9.0 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk Estimates 13

10.0 Aggregate Exposure/Risk Characterization....................................................................... 14

11.0 Cumulative Exposure/Risk Characterization..................................................................... 14

12.0 Occupational Exposure/Risk Characterization .................................................................. 14

12.1 Occupational Handler Exposure/Risk Estimates.............................................................. 14

12.2 Occupational Post-application Exposure/Risk Estimates .............................................. 17

13.0 Public Health and Pesticide Epidemiology Data ............................................................... 18

14.0 References.......................................................................................................................... 18

Appendix A: Data Deficiencies................................................................................................ 19

Appendix B: Toxicity Profile of Primisulfuron-Methyl............................................................... 20

Appendix C: Chemical Identity .................................................................................................... 25

Appendix D: Dietary Exposure/Risk Modeling Inputs and Outputs............................................ 26

Appendix E: Spray Drift Assessment for Primisulfuron-methyl.................................................. 29

Appendix F. TTR and DFR Data Waiver Rationale.................................................................... 32

Appendix G: Review of Human Research................................................................................... 34
Primisulfuron-methyl D425535

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1.0 Executive Summary

Primisulfuron-methyl (methyl 2-[[[[[4,6-bis(difluoromethoxy)-2-

pyrimidinyl]amino]carbonyl]amino]sulfonyl]benzoate) is a sulfonylurea (selective postemergence) herbicide absorbed and transported throughout the plant roots and foliage. 

Primisulfuron-methyl is registered for use to control grass weeds and many types of broad leaf 

weeds. It is currently registered for use on field corn (grown for grain, silage, and seed) and 

popcorn. In addition, several states have FIFRA §24(c) Special Local Need (SLN) registrations 

for use on Kentucky blue grass grown for seed and sod production. It is formulated as a waterdispersible granule (WG) and in water-soluble bags (WSP). Since the last risk assessment

(D280923) and scoping document (D394824), there have been no changes to the primisulfuronmethyl use or residue profiles. However, toxicological endpoints and points of departure (PODs) 

used for risk assessment have been updated to reflect current policies. Dietary exposure to 

primisulfuron-methyl has been reevaluated in order to incorporate updated consumption data and 

drinking water modeling estimates. Non-dietary exposure has also been reevaluated to 

incorporate changes to occupational exposure assessment methodologies (unit exposures) and to 

incorporate a spray drift assessment. There are no risk estimates of concern for the existing uses 

of primisulfuron-methyl; however there are some data deficiencies that remain outstanding. 

2.0 HED Recommendations

2.1 Tolerance Considerations

The existing tolerances for residues of primisulfuron-methyl (40 CFR §180.452) are supported 

by the available residue chemistry data. Codex has not established maximum residue limits 

(MRLs) for residues of primisulfuron-methyl. Canada has established MRLs for primisulfuronmethyl which are harmonized with U.S. tolerances. 

HED notes that the tolerance expression for primisulfuron-methyl in 40 CFR §180.452 requires 

revision to state the following:

(a) General. Tolerances are established for residues of primisulfuron-methyl, including 

its metabolites and degradates, in or on the commodities in the table below. Compliance 

with the tolerance levels specified below is to be determined by measuring only 

primisulfuron-methyl (methyl 2-[[[[[4,6-bis(difluoromethoxy)-2-

pyrimidinyl]amino]carbonyl]amino]sulfonyl]benzoate) in or on the commodity.

2.2 Data Deficiencies 

The analytical reference standards for primisulfuron-methyl expired on 4/30/2015 and are

currently unavailable in EPA’s National Pesticide Standards Repository (NPSR; email 

communication between G. Verdin and J. Van Alstine; 5/7/2015). The registrant is required to 

maintain reasonable amounts of the reference standards for primisulfuron-methyl in the NPSR as 

long as tolerances remain published in 40 CFR §180.452. (See Appendix A for more details.)

3.0 Introduction 

3.1 Use Profile & Anticipated Exposure Pathways 
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Primisulfuron-methyl is formulated as water soluble packets (WSP) and water-dispersible 

granule (WDG) formulations, and only registered for use on corn and bluegrass. Currently 

registered labels include one technical label, four agricultural labels, and eight special local need 

(SLN) state labels. In general, primisulfuron-methyl may be applied to corn and bluegrass once

or twice per year or per growing season. The registered application rates range from 0.018 to 

0.036 lb ai/A. Primisulfuron-methyl may be applied using groundboom and aerial application 

equipment; application via chemigation is not permitted. The primisulfuron-methyl labels 

require occupational handlers to wear baseline personal protective equipment (PPE): long 

sleeved shirts, long pants, shoes, and socks; and chemical resistant gloves. The restricted entry 

intervals (REIs) listed on the primisulfuron-methyl labels are generally 12 hours; however, one 

label (EPA Reg No. 100-923) has an REI listed for 24 hours. This product is co-formulated with 

43.9% sodium salt of dicamba. 

Individuals may be exposed to primisulfuron-methyl via their diet (food and drinking water) and 

agricultural workers may be exposed (dermal and inhalation) to primisulfuron-methyl during 

mixing, loading, and/or applying the herbicide as well as during post-application activities. 

There are no registered uses for primisulfuron-methyl that will result in direct non-dietary nonoccupational (i.e., residential) exposures. However, there is the potential for indirect exposure 

(incidental oral and dermal) to primisulfuron-methyl related to spray drift. 

Table 3.1. Summary of Directions for Use of Primisulfuron-Methyl.

Applic. 

Timing, Type, 

and Equip.

Formulation 

[EPA Reg. 

No.]

Applic. 

Rate (lb 

ai/A)

Max. No. 

Applic. per 

Season

Max. 

Seasonal 

Applic. Rate 

(lb ai/A)

REI 

(Hours)

Use Directions and 

Limitations

Corn (grain, silage, and seed) and Popcorn

Aerial and 

Ground 

Equipment*

Water 

Soluable 

Packets

[100-705]

0.036 1 - 2 0.036 12

PGI- 30 days; PHI silage 

– 45 days; PHI grain- 60 

days

Over the top foliar postemergence with 4- 20 

inches crop height. 

Ground equipment 

applications applied 15 

inches above corn 

canopy

Water 

Dispersible 

Granule

[100-774]

0.018 1 0.018 12

PGI- 30 days; PHI silage 

– 40 days; PHI grain- 60 

days

Over the top foliar postemergence with 4- 20 

inches crop height. 

Ground equipment 

applications applied 15 

inches above corn 

canopy

Water 

Dispersible 

Granule

[100-911]

0.027 1 0.027 12

PGI- 30 days; PHI silage 

– 40 days; PHI grain- 60 

days

Over the top foliar postemergence with 4- 20 

inches crop height. 

Ground equipment 

applications applied 15 
Primisulfuron-methyl D425535

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Table 3.1. Summary of Directions for Use of Primisulfuron-Methyl.

Applic. 

Timing, Type, 

and Equip.

Formulation 

[EPA Reg. 

No.]

Applic. 

Rate (lb 

ai/A)

Max. No. 

Applic. per 

Season

Max. 

Seasonal 

Applic. Rate 

(lb ai/A)

REI 

(Hours)

Use Directions and 

Limitations

inches above corn 

canopy

Water 

Dispersible 

Granule

[100-923]

0.023 1 0.023 24

PGI- 30 days; PHI silage 

– 45 days; PHI grain- 60 

days

Over the top foliar postemergence with 4- 20 

inches crop height. 

Ground equipment 

applications applied 15 

inches above corn 

canopy

Kentucky Bluegrass grown for sod production

Water Soluble 

Packets

[CO-05-0004; 

IL-060002; 

NJ-080001; 

NY-080015]

0.036 1 - 2 0.036 12 None

Kentucky Bluegrass grown for seed production

Water Soluble 

Packets

[ID-990007; 

MN-060003;; 

OR-960025; 

WA-960002]

0.036 1 - 2 0.036 12 None

*Chemigation is not permitted on the registered labels.

REI= Reentry Interval. PGI= Pre-grazing Interval. PHI= Pre-harvest Interval.

3.2 Consideration of Environmental Justice

Potential areas of environmental justice concerns, to the extent possible, were considered in the 

preliminary human health risk assessment for primisulfuron-methyl, in accordance with U.S. 

Executive Order 12898, "Federal Actions to Address Environmental Justice in Minority 

Populations and Low-Income Populations," 

http://epa.gov/compliance/ej/resources/policy/exec_order_12898.pdf. As a part of every 

pesticide risk assessment, OPP considers a large variety of consumer subgroups according to 

well-established procedures. In line with OPP policy, HED estimates risks to population 

subgroups from pesticide exposures that are based on patterns of that subgroup’s food and water 

consumption, and activities in and around the home that involve pesticide use in a residential 

setting. Extensive data on food consumption patterns are compiled by the USDA under the 

National Health and Nutrition Examination Surveys/What We Eat in America 

(NHANES/WWEIA) and are used in pesticide risk assessments for all registered food uses of a 

pesticide. These data are analyzed and categorized by subgroups based on age and ethnic group. 

Additionally, OPP is able to assess dietary exposure to smaller, specialized subgroups and 

exposure assessments are performed when conditions or circumstances warrant. Whenever 

appropriate, non-dietary exposures based on home use of pesticide products and associated risks 

for adult applicators and for toddlers, youths, and adults entering or playing on treated areas 

post-application are evaluated. Further considerations are currently in development as OPP has 
Primisulfuron-methyl D425535

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committed resources and expertise to the development of specialized software and models that 

consider exposure to bystanders and farm workers as well as lifestyle and traditional dietary 

patterns among specific subgroups. 

4.0 Hazard Identification/Toxicology

The toxicology database for primisulfuron-methyl is complete and adequate for risk assessment. 

The last risk assessment for primisulfuron-methyl was conducted in 2002 (W. Hazel; D280923; 

6/28/2002). In 2012, a scoping document (M. Sahafeyan; D394824; 3/7/2012) was completed 

which outlined data gaps for several toxicity studies as required in accordance with the current

40 CFR Part 158 Guidelines. The studies included inhalation toxicity, immunotoxicity and acute 

and subchronic neurotoxicity studies. However, HED has determined that these studies are not 

required at this time (TXR# 0053979, Hazard and Science Policy Council, 0056723). The 

endpoints/PODs selected for risk assessment have been updated to reflect current policy. See 

Appendix B for the primisulfuron-methyl toxicology profile. 

4.1 Summary of Toxicological Effects

The most consistent effect across the database was decreases in body weights observed in rats, 

dogs and mice. In dogs, primisulfuron-methyl also targeted the thyroid (decreased organ weights 

and hyperplasia), liver (decreased organ weights and vacuolization), and the hematopoietic 

system (decreased RBC, hemoglobin, and hematocrit). In mice, liver, kidney, testes, teeth and 

bone toxicity were observed following chronic exposure. These effects were observed following 

sub-chronic and chronic exposure with no progression of toxicity over time. No toxicity was 

observed following a 21-day dermal toxicity study in rabbits. However, a conservative upperbound dermal absorption factor of 30% was estimated using a NOAEL/LOAEL extrapolation 

from the 21-day dermal toxicity (no effects at limit dose of 1000 mg/kg) and developmental 

toxicity (decreased body weight gain at 300 mg/kg) studies in rabbits. 

There were no tumors in the rat chronic toxicity/carcinogenicity study. Primisulfuron-methyl 

produced hepatocellular adenoma, carcinomas, and adenomas/carcinomas combined in both 

sexes in the mouse study. However, the doses where the tumors occurred in mice were 

considered to be excessively toxic by the Cancer Peer Review Committee. There was no 

indication of mutagenicity in the battery of available studies. Primisulfuron-methyl is classified 

as Group D “not classifiable as to human carcinogenicity.”

Increased quantitative susceptibility was observed in the rat developmental toxicity study. 

Primisulfuron-methyl produced delayed ossification in fetal rats in the absence of maternal 

toxicity. No developmental toxicity was observed in the rabbit. Primisulfuron-methyl affected 

reproductive parameters in rats including decreases in testicular/spermatic function. This did not 

affect litter size. Offspring toxicity was also manifested as decreased pup weight. Both 

reproductive and offspring toxicity observed in the two-generation toxicity study were observed 

at the same dose as overt maternal toxicity (decreased parental body weights). No evidence of 

increased susceptibility was seen in the rabbit developmental or rat reproduction toxicity studies. 

In acute lethality studies, primisulfuron-methyl is not acutely toxic via acute oral and inhalation 

exposures (Toxicity Category IV) and is moderately toxic by dermal exposure (Toxicity 

Category III). It is also an eye irritant (Toxicity Category III) but not a skin sensitizer or a 

dermal irritant (Toxicity Category IV). 
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In a pharmacokinetic/metabolism study in rats, primisulfuron-methyl was rapidly absorbed, 

metabolized, and eliminated in the urine and feces. No bioaccumulation was observed. There 

appear to be several metabolic pathways for primisulfuron-methyl. The main pathway is 

hydroxylation of the pyrimidine ring to give rise to the 5-hydroxyprimidinyl metabolite of the 

parent compound (i.e. CGA-239769) followed by isomerization of the pyrimidinyl moiety. 

Bridge cleavage results in the formation of 2-carboxymethylbenzene sulfonamide in the feces 

and saccharin (a cyclization product) in the urine. The corresponding pyrimidinyl moiety is 

further metabolized. There were no major sex differences regarding any aspects of metabolism. 

4.2 Safety Factor for Infants and Children (FQPA Safety Factor)

HED recommends that the FQPA Safety Factor (10X) be reduced to 1X for primisulfuronmethyl. The toxicology database is complete, and there are no concerns/residual uncertainties 

with regard to pre- and/or postnatal toxicity, and no concern for neurotoxicity. Although 

increased quantitative susceptibility was observed in the developmental rat study, HED has low 

concern for effects to infants and children because 1) no developmental effects were seen in the 

rabbit developmental or rat reproduction studies, 2) there are clear NOAELs/LOAELs for the 

fetal effects observed in the developmental rat study, and 3) the endpoints and PODs selected for 

risk assessment are protective of the effects observed in the study. In addition, exposure 

estimates are unlikely to underestimate risk.

4.3 Toxicity Endpoint and Point of Departure Selections

The toxicological endpoints/PODs selected for risk assessment have been changed since the 

previous assessment to reflect current endpoint selection practices. However, it should be noted 

that the NOAELs and LOAELs of the selected endpoints/PODs and those presented in the 

toxicology profile table (Appendix B) have not been updated to comply with current policies. 

Therefore, the endpoints/PODs selected for risk assessment may be conservative. The PODs 

selected for risk assessment are protective of the effects observed in the primisulfuron-methyl 

database. A summary of toxicological doses and endpoints used in the primisulfuron-methyl 

human health risk assessments is presented below:

Table 4.3.1 Summary of Primisulfuron-methyl Doses and Endpoints for Use in Dietary and NonOccupational Risk Assessments. 

Exposure/

Scenario

Point of Departure

(POD)

Uncertainty/

FQPA Safety 

Factors

LOC for Risk 

Assessment

Study and Toxicological Effects

Acute dietary

(General 

Population and 

females 13-49)

No single dose effect relevant to the general US population including infants and children and 

females 13-49 years of age was identified in the toxicity studies conducted with primisulfuronmethyl.

Chronic dietary

(all populations)

NOAEL = 

25 mg/kg/day

UFA = 10x

UFH = 10x

FQPA SF= 1x

cPAD = 0.25 

mg/kg/day

Chronic toxicity study in dogs.

LOAEL 125 mg/kg/day based on (i) 

decreased erythrocytes, 

hemoglobin, and hematocrit; (ii) 

increased platelets; (iii)

increased relative (to body) liver 

weights; (iv) increased incidence of 

pale livers, vacuolar liver changes, 

and thyroid hyperplasia.
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Table 4.3.1 Summary of Primisulfuron-methyl Doses and Endpoints for Use in Dietary and NonOccupational Risk Assessments. 

Exposure/

Scenario

Point of Departure

(POD)

Uncertainty/

FQPA Safety 

Factors

LOC for Risk 

Assessment

Study and Toxicological Effects

Incidental oral 

(short-term)

NOAEL= 

50 mg/kg/day

UFA = 10x

UFH = 10x

FQPA SF= 1x

LOC for MOE 

= 100

2-Generation repro study in rats 

LOAEL = 250 mg/kg/day based on 

decreased pup body weights.

Dermal short-

(1-30 days) and 

intermediateterm (1-6 

months)

NOAEL = 100 

mg/kg/day

(30%) dermal 

absorption

UFA = 10x

UFH = 10x

FQPA SF= 1x

LOC for MOE 

= 100

Developmental Toxicity in Rats

LOAEL = 500 mg/kg/day based on 

incomplete or lack of ossification of 

several bones hyoids, interparietals, 

ischium, os pubis and bipartite 

centrum/vertebrae)

Cancer (oral) Primisulfuron-methyl was classified as Group D “not classifiable as a human carcinogen” by

the Cancer Peer Review Committee

Point of Departure (POD) = a data point or estimated point derived from observed dose-response data, which is used 

to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human 

exposures. UF = Uncertainty Factor. UFA = extrapolation from animal to human (interspecies). UFH = potential 

variation in sensitivity among members of the human population (intra-species). FQPA SF = FQPA Safety Factor. 

NOAEL = No Observed Adverse Effect Level. LOAEL = Lowest Observed Adverse Effect Level. PAD = 

Population Adjusted Dose (a = acute, c = chronic). RfD = Reference Dose. LOC= Level of Concern.

Table 4.3.2 Summary of Primisulfuron-methyl Doses and Endpoints for Use in Occupational Risk 

Assessments.

Exposure/

Scenario

Point of Departure

(POD)

Uncertainty/

FQPA Safety

Factors

LOC for Risk 

Assessment

Study and Toxicological Effects

Dermal short-

(1-30 days) and 

intermediateterm (1-6 

months)

NOAEL = 100 

mg/kg/day

(30%) dermal 

absorption

UFA = 10x

UFH = 10x

FQPA SF= 1x

LOC for MOE 

= 100

Developmental Toxicity in Rats

LOAEL = 500 mg/kg/day based on 

incomplete or lack of ossification of 

several bones hyoids, interparietals, 

ischium, os pubis and bipartite 

centrum/vertebrae)

Inhalation short-

(1-30 days) and 

intermediateterm (1-6 

months)

NOAEL= 

50 mg/kg/day

UFA = 10x

UFH = 10x

FQPA SF= 1x

LOC for MOE 

= 100

2-Generation repro study in rats 

LOAEL = 250 mg/kg/day based on 

decreased pup body weights. 

Point of Departure (POD) = a data point or estimated point derived from observed dose-response data, which is used 

to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human 

exposures. UF = Uncertainty Factor. UFA = extrapolation from animal to human (interspecies). UFH = potential 

variation in sensitivity among members of the human population (intra-species). FQPA SF = FQPA Safety Factor. 

NOAEL = No Observed Adverse Effect Level. LOAEL = Lowest Observed Adverse Effect Level. PAD = 

Population Adjusted Dose (a = acute, c = chronic). MOE = Margin Of Exposure. LOC = Level Of Concern. 

4.4 Endocrine Disruptor Screening Program

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and 

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, 

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, 

and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and 
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chronic studies that assess growth, developmental and reproductive effects in different 

taxonomic groups. As part of its most recent registration decision for primisulfuron-methyl.,

EPA reviewed these data and selected the most sensitive endpoints for relevant risk assessment 

scenarios from the existing hazard database. However, as required by FFDCA section 408(p), 

primisulfuron-methyl is subject to the endocrine screening part of the Endocrine Disruptor 

Screening Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including pesticide 

active and other ingredients) may have an effect in humans or wildlife similar to an effect 

produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator 

may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and 

establish a dose-response relationship between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between 

October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 

chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. A second list 

of chemicals identified for EDSP screening was published on June 14, 20131and includes some 

pesticides scheduled for Registration Review and chemicals found in water. Neither of these 

lists should be construed as a list of known or likely endocrine disruptors. 

For further information on the status of the EDSP, the policies and procedures, the lists of 

chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our 

website.2

5.0 Residue Chemistry

The existing residue chemistry database for primisulfuron-methyl is complete and adequate for 

risk assessment purposes. No residue chemistry data are required at this time. The qualitative 

nature of the residues of primisulfuron-methyl in plants and animals are adequately understood. 

HED determined that the residue of concern for risk assessment and tolerance enforcement in 

plants, livestock commodities, and drinking water is primisulfuron-methyl only (W. Hazel,

Metabolism Assessment Review Committee; D282837; 5/15/2002). Adequate methods are 

available for the enforcement of the current tolerance expression (W. Hazel et al.; D280923; 

06/28/2002).

The structure and the physical/chemical properties are summarized in Appendix C. 

6.0 Dietary Risk Assessment

 

1 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of 

chemicals.

2 http://www.epa.gov/endo/
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An updated dietary exposure assessment has been completed for primisulfuron-methyl for the 

DRA to incorporate updated food consumption data and drinking water modeling estimates. The 

use pattern, PODs, and residue inputs to the dietary assessment have not changed since the 

previous assessment. 

6.1 Water Residue Profile 

Screening ground water-sourced drinking water exposure estimates were generated with the 

Pesticide Root Zone Model for GroundWater (PRZM-GW; v.1.07) for use in the sulfonylurea 

(SU) dietary risk assessments. Rather than produce chemical-specific estimated drinking water 

concentrations (EDWCs) following the usual assessment procedures, EFED provided coarsescreen estimates that should exceed upper-bound chemical-specific EDWCs for any SU. This 

was achieved by using model inputs that represent the use pattern of highest exposure from any 

SU, the highest soil mobility of any SU residue of concern, and persistence to any route of 

degradation over time. The resulting highest coarse-screen EDWCs from PRZM-GW can be 

used as a conservative estimate of exposure and are summarized in Table 6.1.1 (G. Orrick; 

D427429; 8/12/2015). 

The chronic dietary assessment for primisulfuron-methyl used the coarse-screen postbreakthrough mean value of 492 μg/L (0.492 ppm). 

Table 6.1.1 PRZM-GW Coarse-Screen EDWCs for Sulfonylureas1.

Modeled Scenario Kd or KOC

Initial Application 

Dates (days postemergence)

Max. Daily Conc. 

(μg/L)

Mean 

Breakthrough 

Time (yrs)

Postbreakthrough 

Mean (μg/L)

WI corn

Kd 7 449 11.5 415

KOC 7 504 6.9 425

Delmarva (DMV)

corn

Kd 7 489 5.3 369

KOC 7 560 3.3 378

FL citrus

Kd 7 429 3.2 351

KOC 7 467 2.3 349

FL potato

Kd 7 375 2.6 272

KOC 7 407 2.2 275

GA peanut

Kd 7 197 5.2 156

KOC 7 206 3.9 158

NC cotton

Kd 7 640 8.7 492

Kd 37 641 8.7 491

Kd 67 637 8.7 490

KOC 7 742 5.7 484

KOC 37 751 5.7 483

KOC 67 744 5.7 482

1 Maximum values are bolded.

6.2 Dietary (Food + Water) Exposure Assessment 

HED has conducted a screening-level chronic dietary risk assessment for primisulfuron-methyl

using tolerance-level residues in foods and the sulfonylurea-class-wide screening-level estimate 

of residues in drinking water (G. Orrick; D427429; 8/12/2015). Exposure and risk estimates 

were obtained from the Dietary Exposure Evaluation Model using the Food Commodity Intake 
Primisulfuron-methyl D425535

Page 12 of 34

Database (DEEM-FCID; version 3.18). The model uses food consumption data from the 2003-

2008 National Health and Nutrition Examination Survey/What We Eat in America 

(NHANES/WWEIA) database, coupled with recipe files and residues in foods, to derive 

estimates of dietary exposure and risk. 

Generally, HED is concerned when chronic dietary exposure estimates exceed 100% of the 

chronic population adjusted dose (cPAD). Chronic dietary risk estimates (food and drinking 

water) are not of concern for the general U.S. population or any other population subgroup

(Table 6.2.1). The chronic exposure estimate utilized 4.3% of the cPAD for the general U.S. 

population and 11% of the cPAD for all infants (<1 year old), the most highly-exposed 

population subgroup. Because of the very conservative assumptions used in the analysis 

(tolerance-level residues, 100% crop treated, upper-bound modeled drinking water estimates), 

actual exposure and risk are expected to be much lower than those shown in Table 6.2.1. The 

listings of inputs and outputs to the assessment are included in Appendix D. HED did not 

conduct an acute dietary exposure/risk assessment due to the lack of an endpoint appropriate for 

acute dietary assessment. Primisulfuron-methyl is classified as Group D, “Not Classifiable as to 

Human Carcinogenicity;” therefore, a cancer dietary assessment was not conducted for 

primisulfuron-methyl. 

Table 6.2.1 Summary of Chronic Dietary Exposure (Food and Drinking Water) and Risk for 

Primisulfuron-methyl1.

Population Subgroup

Chronic Dietary

Dietary Exposure 

(mg/kg/day) % cPAD

General U.S. Population 0.010704 4.3

All Infants (<1 year old) 0.027032 11

Children 1-2 years old 0.016319 6.5

Children 3-5 years old 0.013565 5.4

Children 6-12 years old 0.009683 3.9

Youth 13-19 years old 0.007893 3.2

Adults 20-49 years old 0.010595 4.2

Adults 50-99 years old 0.010422 4.2

Females 13-49 years old 0.01053 4.2

1 Population with the greatest exposure is in bold. Exposure and risk estimates calculated using DEEM version 3.18.

7.0 Residential (Non-Occupational) Exposure/Risk Characterization

There are no registered residential uses or occupational uses resulting in residential exposure to 

primisulfuron-methyl. Therefore, a quantitative residential exposure assessment was not 

performed. 

8.0 Non-Occupational Spray Drift Exposure and Risk Estimates

A detailed description about HED’s spray drift policy and how to evaluate the drift potential and 

associated risks is available in Appendix E.

8.1 Risk Estimates from Lawn Deposition Adjacent to Applications

A spray drift assessment was conducted to address the deposition of residues from adjacent 

commercial pesticide applications. The spray drift risk estimates are based on an estimated 

deposited residue concentration as a result of the screening level agricultural application 
Primisulfuron-methyl D425535

Page 13 of 34

scenarios. Primisulfuron-methyl is an herbicide registered for use on corn (grown for grain, 

silage, and seed) and bluegrass (grown for seed and sod production). Registered use products 

can be applied via groundboom and aerial equipment. The recommended drift scenario 

screening level options are listed below: 

 Aerial applications are based on the use of AgDrift® Tier 1 aerial option for a fine to 

medium spray type and a series of other parameters(e.g., wind vector assumed to be 10 

mph in a downwind direction for entire application/drift event).

 Groundboom applications are based on the AgDrift® option for high boom height and 

using very fine to fine spray type using the 90th percentile results. 

Risk estimates for Children (1 to <2 years old), from combined incidental oral and dermal 

exposure, and for adults from dermal exposure to primisulfuron-methyl related to spray drift are 

not of concern at the field edge for groundboom and aerial applications (Table 8.1.1 and 8.1.2). 

Based on the total applicable LOC of 100, all MOEs are ≥100.

Table 8.1.1 Adult Dermal Risk Estimates (MOEs) Related to Spray-Drift Exposure for Primisulfuronmethyl.

Lifestage Crop Application 

Method

Spray Type / 

Nozzle 

Configuration

Application 

Rate

(lb ai/A)

Estimated 

TTRt

(ug/cm2)

Dermal MOE

At Edge

Adult Corn

Aerial

High Boom 

Very fine to 

Fine 0.036 0.004

83,000

Groundboom Fine to 

Medium 110,000

MOE= Margins of Exposure. TTRt= Turf Transferable Residue 

Table 8.1.2 Children (1 to <2 years old) Dermal & Incidental Oral Risk Estimates (MOEs) Related to 

Spray-Drift Exposure for Primisulfuron-methyl.

Lifestage Crop Application 

Method

Spray Type / 

Nozzle 

Configuration

Application 

Rate

(lb ai/A)

Estimated 

TTRt

(ug/cm2)

Dermal 

MOE

At Edge

Incidental 

Oral MOE

At Edge

Children 

(1 to < 2 

years old)

Corn

Aerial

High Boom 

Very fine to 

Fine 0.036 0.004

49,000 350,000

Groundboom Fine to 

Medium 67,000 490,000

MOE= Margins of Exposure. TTR = Turf Transferable Residue 

9.0 Non-Occupational Bystander Post-Application Inhalation Exposure and Risk 

Estimates

Volatilization of pesticides may be a source of post-application inhalation exposure to 

individuals 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 the SAP’s final report on 

March 2, 2010 (http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html). The 

agency has evaluated the SAP report and has developed a Volatilization Screening Tool and a 

subsequent Volatilization Screening Analysis.3 During Registration Review, the agency will 

 

3 Available at: http://www.regulations.gov/#!docketDetail;D=EPA-HQ-OPP-2014-0219.
Primisulfuron-methyl D425535

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utilize this analysis to determine if data (i.e., flux studies, route-specific inhalation toxicological 

studies) or further analysis is required for primisulfuron-methyl.

10.0 Aggregate Exposure/Risk Characterization

The Food Quality Protection Act of 1996 directs EPA to assess aggregate exposure to pesticide 

chemical residues, including all anticipated dietary exposures and all other exposures for which 

there is reliable information. In the case of primisulfuron-methyl, aggregate exposure and risk 

estimates are equivalent to the dietary exposure and risk estimates in Section 6 and are not of 

concern. 

11.0 Cumulative Exposure/Risk Characterization

In 2015, EPA’s Office of Pesticide Programs released a guidance document entitled, Pesticide 

Cumulative Risk Assessment: Framework for Screening Analysis 

[http://www.epa.gov/oppfead1/cb/csb_page/updates/2015/framework-for-screeninganalysis.html]. This document provides guidance on how to screen groups of pesticides for 

cumulative evaluation using a two-step approach beginning with the evaluation of available 

toxicological information and if necessary, followed by a risk-based screening approach. This 

framework supplements the existing guidance documents for establishing common mechanism 

groups (CMGs)4and conducting cumulative risk assessments (CRA)5. The Agency has utilized 

this framework to evaluate the SUs of which primisulfuron-methyl is a member (J. D’Agostino; 

D428798; 9/9/2015). Although the SUs share some chemical and toxicological characteristics, 

the toxicological database does not support a testable hypothesis for a common mechanism of 

action. No further mechanistic data are required and no further cumulative evaluation is 

necessary.

12.0 Occupational Exposure/Risk Characterization

Based on current labeling, types of equipment and techniques that can potentially be used, 

occupational handler exposure is expected from the registered uses of primisulfuron-methyl on 

corn and bluegrass. Occupational handlers are anticipated to have short-term (1-30 days) and 

intermediate-term (1-6 months) dermal and inhalation exposures. Long-term exposures (more 

than 6 months) are not anticipated.

12.1 Occupational Handler Exposure/Risk Estimates

In support of Registration Review, an updated occupational exposure assessment for 

primisulfuron-methyl was conducted for mixers/loaders and applicators for aerial and 

groundboom applications of the WSP and WDG formulations. The assessment was based on the 

maximum registered application rate of 0.027 lbs ai/A for WDG formulations and 0.036 lb ai/A 

for WSP formulations and maximum area treated per day. 

Handler exposure and risk were calculated at baseline (long pants, a long-sleeved shirt, no 

chemical-resistant gloves, and no respirator). Personal Protective Equipment (PPE)

 

4 Guidance For Identifying Pesticide Chemicals and Other Substances that have a Common Mechanism of Toxicity

(USEPA, 1999)

5 Guidance on Cumulative Risk Assessment of Pesticide Chemicals That Have a Common Mechanism of Toxicity

(USEPA, 2002)
Primisulfuron-methyl D425535

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recommended on registered primisulfuron-methyl labels typically includes the addition of

chemical-resistant gloves. 

The standard body weight for the general population (80 kg) was used for all inhalation exposure 

scenarios covered in this risk assessment since the endpoints selected for the inhalation route

were not developmental and/or fetal effects. However, since the dermal PODs are based on 

developmental and/or fetal effects, the body weight appropriate for dermal assessments is 69 kg.

A dermal absorption factor of 30% was used for the exposure assessment and is based on a 

NOAEL/LOAEL extrapolation from the 21-day dermal toxicity (no effects at limit dose of 1000 

mg/kg) and developmental toxicity (decreased body weight gain at 300 mg/kg) studies in rabbits. 

Since no inhalation absorption data are available, toxicity by the inhalation route is considered to 

be equivalent to the estimated toxicity by the oral route of exposure.

For all scenarios, dermal and inhalation risk estimates were not of concern (i.e., MOEs ≥ 100) 

with either baseline protection (long-sleeved shirt, long pants, shoes plus socks, no gloves, or 

respirator) or with the use of gloves, as recommended on some labels (see Table 12.1.1). 
Page 16 of 34

Table 12.1.1. Summary of Occupational Handler Exposure and Risk Estimates for Primisulfuron-methyl.

Scenario Crop / Target 

Category

Application 

Ratea

Amount 

Handled / 

Area 

Treatedb

Dermal Unit 

Exposures 

(ug/lb ai)

Mitigationc

Inhalation Unit 

Exposures 

(ug/lb ai)

Mitigationc

Dermal Dose 

(mg/kg/day)d

Dermal 

MOEe

Inhalation 

Dose (mg/kgday)f

Inhalation 

MOEg

Mixer/Loader

WDG 

Aerial application Corn 0.027 1200 227SL/No G

8.96

No-R

0.032 3,100 0.0036 14,000

WDG 

Groundboom 

application

Corn 0.027 200 227

SL/No G

8.96

No-R

0.00535 19,000 0.000605 83,000

WSP

Aerial application

Bluegrass

0.036

350 9.8

EC

0.24

EC

0.000535 190,000 0.0000378 1,300,000

Corn 1200 0.00184 54,000 0.00013 380,000

WSP 

Groundboom 

application

Bluegrass 

0.036

80 9.8

EC

0.24

EC

0.000123 810,000 0.000009 5,800,000

Corn 200 0.000307 330,000 0.0000216 2,300,000

Applicator

Aerial application Bluegrass 0.036 350 2.08

EC

0.0049

EC

0.000114 880,000 0.00000077 65,000,000

Corn 1200 0.000391 260,000 0.0000027 19,000,000

Groundboom 

application

Bluegrass 0.036 80 78.6

SL/No G

0.34

No-R

0.000983 100,000 0.000012 4,100,000

Corn 200 0.00246 41,000 0.000031 1,600,000

Flagger

Aerial application Corn and 

Bluegrass 0.036 350 11SL/No G

0.35

No-R

0.000604 170,000 0.000055 910,000

a. Based on maximum single application rates on registered labels (Table 3.1).

b. Based on the Science Advisory Council for Exposure Policy 9.1: Standard Values for Daily Acres Treated in Agriculture. 

c. Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (March, 2013). Mitigation Level: SL/No G = single layer clothing/no gloves; SL/G = single 

layer of clothing/gloves; No-R = no respirator; EC = engineering controls (e.g., enclosed cockpit for aerial applicators).

d. Dermal Dose (mg/kg/day) = [Rate (lb ai/A or lb ai/gal) * UE (mg/lb ai) * Acres Treated or Amount handled (A or gal/day)] * Dermal Absorption (30%) /BW (69 kg).

e. Dermal MOE = POD (100 mg/kg/day)/ Dermal Dose (mg/kg/day). LOC = 100.

f. Inhalation Dose (mg/kg/day) = [Rate (lb ai/A or lb ai/gal) * UE (mg /lb ai) * Acres Treated or Amount handled (A or gal/day)] /BW (80 kg).

g. Inhalation MOE = POD (50 mg/kg/day)/ Inhalation Dose (mg/kg/day). LOC = 100.
Primisulfuron-methyl D425535

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12.2 Occupational Post-application Exposure/Risk Estimates

Occupational exposures to workers re-entering primisulfuron-methyl treated agricultural use 

sites are expected; therefore, a quantitative post-application assessment was conducted for those 

sites. Based on the use directions on product labels, foliar exposure is expected since 

applications are generally made post-emergent when the corn is 4-20 inches in height and postemergent to grass (target weed) growth. Chemical-specific turf transferable residue data and 

dislodgeable foliar residue data were not available for primisulfuron-methyl; therefore, default 

assumptions were used to estimate transferable residue. A discussion of the dislodgeable foliar 

residue and turf transferable residue data is provided in Appendix F.

The results of the dermal post-application exposure and risk assessment indicate that dermal 

MOEs ≥ LOC (MOEs ≥ 100) on day 0 for all scenarios, and, therefore, are not of concern to 

HED. 

Table 12.2.1. Summary of Occupational Post-application Dermal Exposure and Risk Estimates.

Crop Crop Height / 

Foliage Density Activity

Transfer 

Coefficient 

(cm2/hr)

Residue1,2 

(ug/cm2)

Dermal Dose2

(mg/kg-day) MOE3

DAT (Day After Treatment) = 0 (12 

hours)

Corn

Field / row crop, tall Irrigation (hand set) 1,900

0.11

0.007 15,000

Field / row crop, tall Scouting 1,100 0.004 26,000

Field / row crop, tall Scouting 210 0.001 140,000

Field / row crop, tall Hand weeding 70 0.00025 410,000

Kentucky 

Bluegrass 

(grown for seed 

production)

Field / row crop, 

low / medium Irrigation (hand set) 1,900

0.11

0.007 15,000

Field / row crop, 

low / medium Scouting 1,100 0.004 26,000

Kentucky 

Bluegrass 

(grown for sod 

production)

Turf / sod Maintenance 6700

0.0042

0.001 110,000

Turf / sod Harvesting, Slab 6700 0.001 110,000

Turf / sod Transplanting/Planting 6700 0.001 110,000

1. DFR = Application Rate × F × (1-D)t × 4.54E8 μg/lb × 2.47E-8 acre/cm2; where F = 0.25 and D = 0.10 per day

2. TTR = Application Rate × F × (1-D)t × 4.54E8 μg/lb × 2.47E-8 acre/cm2; where F = 0.1 and D = 0.10 per day.

3. Daily Dermal Dose = [DFR (μg/cm2) × Transfer Coefficient × 0.001 mg/μg × 8 hrs/day × dermal absorption (30 %)]  BW (69 kg).

4. MOE = POD (100 mg/kg/day) / Daily Dermal Dose. 

Primisulfuron-methyl is not acutely toxic via acute oral and inhalation exposures (Toxicity 

Category IV) and is moderately toxic by dermal exposure (Toxicity Category III). It is also an 

eye irritant (Toxicity Category III) but not a skin sensitizer or a dermal irritant (Toxicity 

Category IV). Under 40 CFR 156.208 (c) (2) (iii), pesticide active ingredients classified as 

Toxicity Category III or IV for acute dermal, eye irritation, and primary skin irritation are 

assigned a 12-hour Restricted Entry Intervals (REI). Therefore, the Worker Protection Standard 

REI6of 12 hours is adequate to protect workers from post-application exposures to 

primisulfuron-methyl. The occupational post-application assessment indicated no risks of 

 

6 As specified in 40 CFR part 156 subpart K
Primisulfuron-methyl D425535

Page 18 of 34

concern on the day of application as well; therefore, HED recommends a 12-hour REI for the 

primisulfuron-methyl labels. 

13.0 Public Health and Pesticide Epidemiology Data

Incident databases were previously reviewed for primisulfuron-methyl in 2011 (S. Recore; 

D396007; 12/8/2011) and updated in 2015 (S. Recore; D428297; 7/23/2015). There were no 

incidents reported to the OPP Incident Data System (IDS) from January 1, 2006 to November 2, 

2011. It was concluded that “there does not appear to be a concern at this time that would 

warrant further investigation.” The current IDS analysis, from January 1, 2012 through May 27, 

2015, shows no incidents reported in Main or Aggregate IDS involving the active ingredient 

primisulfuron-methyl. Additionally, a query of the Centers for Disease Control and

Prevention/National Institute for Occupational Safety and Health (CDC/NIOSH) Sentinel Event 

Notification System for Occupational Risk-Pesticides (SENSOR) 1998-2011 identifies one case 

involving primisulfuron-methyl. This case was low severity and involved multiple active 

ingredients. 

Based on the continued low frequency and low severity of incident cases reported for 

primisulfuron-methyl in both IDS and NIOSH SENSOR-Pesticides, there does not appear to be a 

concern at this time that would warrant further investigation. Primisulfuron-methyl is also not 

included in the Agricultural Health Study (AHS), and therefore this study does not provide any 

additional information on primisulfuron-methyl. The Agency will continue to monitor the 

incident information and if a concern is triggered, additional analysis will be conducted.

14.0 References

Table 14.1 References

Author Barcode Date Title

M. Sahafeyan 

et al. D394824 03/07/2012 Primisulfuron-methyl. Health Effects Division (HED) Scoping Document for Registration Review.

W. Hazel et al. D280923 06/28/2002

PP# 6F4752. Primisulfuron-methyl. Proposed Use and Tolerances 

in/on Kentucky Bluegrass Grown for Seed. Human Health Risk 

Assessment and Tolerance Reassessment. DP Barcode D280923. 

P.C. Code 128973. Case 287952. Submission S610273.

W. Hazel D282837 05/15/2002

Primisulfuron-methyl (128973): Results of the HED Metabolism 

Assessment Review Committee (MARC) Electronic Review. DP 

Barcode: D282837.

G. Orrick D427429 8/12/2015 Drinking Water Exposure Assessment for the Registration Review of 

22 Sulfonylurea Herbicides.

S. Recore D428297 7/23/2015 Primisulfuron-methyl: Tier I Update Review of Human 

Incidents/Epidemiology for Draft Risk Assessment

S. Hanley D280999 5/22/2002 Primisulfuron-methyl: Occupational and Residential Exposure and 

Risk Assessment/Characterization for the Proposed use on Kentucky 

Bluegrass
Primisulfuron-methyl D425535

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Appendix A: Data Deficiencies 

Submittal of Analytical Reference Standards (860.1650)

The analytical reference standards for primisulfuron-methyl expired on 4/30/2015 and are

currently unavailable in EPA’s National Pesticide Standards Repository (NPSR; email 

communication between G. Verdin and J. Van Alstine, 5/7/2015). The registrant is required to 

maintain reasonable amounts of the reference standards for primisulfuron-methyl in the NPSR as 

long as tolerances remain published in 40 CFR §180.452. When necessary, new reference 

standards, or updated certificates of analysis (COAs), should be sent to the Analytical Chemistry 

Branch (ACB), which is located at Fort Meade, MD. It should be sent to the attention of either 

Theresa Cole or Thuy Nguyen at the address listed below, along with a letter of transmittal. 

Please note that the full 9-digit ZIP Code is required, or the mail will be returned to the 

registrant. 

USEPA

National Pesticide Standards Repository

Analytical Chemistry Branch/BEAD/OPP

701 Mapes Road

Fort George G. Meade, MD 20755-5350

The letter of transmittal should include the assay of the standard, name of the analytical method 

used, a statement of principal impurities, purification procedures employed, storage 

requirements, and special precautions for safe handling. Replacement of standards, or updated 

COAs, may be required periodically if supplies are exhausted, if the standards expire, or if 

decomposition occurs during storage. Material Safety Data Sheets (MSDSs) must accompany all 

analytical standards as specified by the Occupational Safety and Health Administration (OSHA) 

in 29CFR §1910.1200. 
Primisulfuron-methyl D425535

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Appendix B: Toxicity Profile of Primisulfuron-Methyl 

B.1. Toxicity Requirements

The toxicology requirements (40 CFR 158.340) for Primisulfuron-methyl are presented below.

TABLE B.1 Toxicology Data Requirements for Primisulfuron Methyl.

Test Required Satisfied

870.1100 Acute Oral Toxicity .....................................................................

870.1200 Acute Dermal Toxicity ................................................................

870.1300 Acute Inhalation Toxicity............................................................

870.2400 Primary Eye Irritation ..................................................................

870.2500 Primary Dermal Irritation ............................................................

870.2600 Dermal Sensitization....................................................................

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

870.3100 Oral Subchronic (Rodent)............................................................

870.3150 Oral Subchronic (Non-Rodent)....................................................

870.3200 21/28-Day Dermal .......................................................................

870.3250 90-Day Dermal ............................................................................

870.3465 21/90 -Day Inhalation..................................................................

yes

yes

yes

no

no

yes

yes

yes

no

no1

870.3700a Developmental Toxicity (Rodent) ...............................................

870.3700b Developmental Toxicity (Non-Rodent).......................................

870.3800 Reproduction ...............................................................................

yes

yes

yes

yes

yes

yes

870.4100a Chronic Toxicity (Rodent)...........................................................

870.4100b Chronic Toxicity (Non-Rodent) ..................................................

870.4200a Oncogenicity (Rat).......................................................................

870.4200b Oncogenicity (Mouse) .................................................................

870.4300 Chronic/Oncogenicity..................................................................

yes

yes

yes

yes

yes

yes

yes

yes

yes

yes

870.5100 Mutagenicity – Gene Mutation (Bacterial)..................................

870.5300 Mutagenicity – Gene Mutation (Mammalian) .............................

870.5375 Mutagenicity – Structural Chromosomal Aberrations.................

870.5395 Mutagenicity – Mammalian Erythrocyte Micronucleus..............

870.5550 Mutagenicity – Unscheduled DNA Synthesis .............................

870.5915 Mutagenicity – In Vivo Sister Chromatid Exchange....................

yes

yes

yes

no

no

no

yes

no2

no2

yes

yes

no

870.6100a Acute Delayed Neurotoxicity (Hen) ............................................

870.6100b 90-Day Neurotoxicity (Hen)........................................................

870.6200a Acute Neurotoxicity Screening Battery (Rat)..............................

870.6200b 90-Day Neurotoxicity Screening Battery (Rat) ...........................

870.6300 Developmental Neurotoxicity......................................................

no

no

yes

yes

no

no

no

no1

no1

no

870.7485 General Metabolism ....................................................................

870.7600 Dermal Penetration ......................................................................

yes

no

yes

no

870.7800 Immunotoxicity yes No

1

1) The Hazard and Science Policy Council (HASPOC) determined that subchronic inhalation, acute and subchronic neurotoxicity 

and immunotoxicity studies are not required.

2) Mutagenicity studies were submitted prior to the 1991 mutagenicity test battery update and are considered to 

fulfill the guideline requirements.
Primisulfuron-methyl D425535

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B.2. Toxicity Profiles

TABLE B.2.1 Acute Toxicity Profile for Technical Primisulfuron-Methyl. 

Guideline 

Number

Study Type MRID 

Number

Results Tox

Category

870.11 Acute Oral - Rat 40331206 LD50 > 5050 mg/kg IV

870.12 Acute Dermal - Rabbit 40331207 LD50 > 2010 mg/kg III

870.13 Acute Inhalation - Rat 40331208 LC50 > 4.81 mg/L IV

870.24 Acute Eye Irritation - Rabbit 40331209 No corneal opacity, conjunctivitis 

reversible by 72 hours

III

870.25 Acute Dermal Irritation -

Rabbit

40331210 Not a dermal irritant IV

870.26 Skin Sensitization - Guinea 

Pig

40331211 Not a skin sensitizer N/A

870.11 Acute Oral - Rat 40331206 LD50 > 5050 mg/kg IV

870.12 Acute Dermal - Rabbit 40331207 LD50 > 2010 mg/kg III

* NA = Not Applicable. 

TABLE B.2.2 Subchronic, Chronic and Other Toxicity Profile for Primisulfuron-Methyl. 

Guideline

Number

Study Title MRID Number Results

870.3100 90-Day oral 

toxicity in rats

40331218 (1987)

Acceptable/guideline

0, 10, 300, 3000, 

10,000, or 20,000 ppm 

(equivalent to 0, 0.5, 

15, 150, 500, or 1000 

mg/kg/day based on 1 

ppm = 0.05 mg/kg/day)

NOAEL = 15 mg/kg/day

LOAEL = 150 mg/kg/day based on decreased body 

weight gain and food consumption/efficiency.

870.3150 90-Day oral 

toxicity in dogs

40331219 (1987)

Acceptable/guideline

0, 25, 1000, or 10,000 

ppm (equivalent to 0, 

0.6, 25, or 250 

mg/kg/day)

NOAEL = 25 mg/kg/day. 

LOAEL = 250 mg/kg/day based on decreased body 

weight, body weight gain, food 

consumption/efficiency, erythrocytes, Hb, 

hematocrit, and thyroid/parathyroid weight. 

Platelets and prothrombin time were increased. In 

the thyroid, mild to severe colloid depletion in the 

small follicles and moderate to severe parafollicular 

cell hyperplasia were observed.

870.3200 21-day dermalrabbit41337601 and 

41135302 (1989)

acceptable/guideline

10, 100, or 1000 

mg/kg/day

NOAEL = 1000 mg/kg/day (limit dose). 

LOAEL = not observed

870.3700a Prenatal 

developmental in 

rats 

40874701 (1988)

acceptable/guideline

0, 100, 500, or 1000 

mg/kg/day

maternal toxicity:

NOAEL > 1000 mg/kg/day. (HDT)

developmental toxicity:

NOAEL = 100 mg/kg/day. 

LOAEL = 500 mg/kg/day based on incomplete or 

lack of ossification of several bones hyoids, 

interparietals, ischium, os pubis and bipartite 

centrum/vertebrae)
Primisulfuron-methyl D425535

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TABLE B.2.2 Subchronic, Chronic and Other Toxicity Profile for Primisulfuron-Methyl. 

Guideline

Number

Study Title MRID Number Results

870.3700b 870.3700b

Prenatal 

developmental in 

rabbits

40331220 (1987)

acceptable/guideline

0, 10, 300, or 600 

mg/kg/day

Maternal toxicity 

NOAEL = 10 mg/kg/day. 

LOAEL = 300 mg/kg/day based on abortion and 

decreased body weight gain

Developmental toxicity 

NOAEL = 600 mg/kg/day (HDT) 

870.3800 Reproduction and 

fertility effects in 

rats

40512009 (1987)

acceptable/guideline

0, 10, 1000, or 5000 

ppm (equivalent to 0, 

0.5, 50, or 250 

mg/kg/day based on 1 

ppm = 0.05 mg/kg/day)

Parental Toxicity:

NOAEL =50 mg/kg/day

LOAEL =250 mg/kg/day based on decreased body 

weight (both generation). 

Reproductive Toxicity: 

NOAEL =50 mg/kg/day

LOAEL =250 mg/kg/day based on increased 

seminiferous tubule atrophy and aspermatogenesis 

with a relative aspermia in the epididymides (F1 

generation)

Offspring Toxicity:

NOAEL =50 mg/kg/day 

LOAEL =250 mg/kg/day based on decreased pup 

weight (F1 generation)

870.100b Chronic toxicity 

dogs

40512008 (1987)

acceptable/guideline

0, 25, 1000, or 

10,000/5000 ppm 

(equivalent to 0, 0.6, 

25, or 250/125 

mg/kg/day)

NOAEL = 25 mg/kg/day

LOAEL= 250/125 mg/kg/day based on decreased 

erythrocytes, Hb, and hematocrit and increased 

platelets, relative liver weight, pale liver, vacuolar 

liver, and thyroid hyperplasia.

870.4300 Chronic toxicity 

and 

carcinogenicity 

in rats

40856502 (1988)

acceptable/guideline

0, 10, 300, 3000, 

10,000 (reduced to 

8000 after 13 weeks) 

(equivalent to 0, 0.5, 

15, 150, or 500 

mg/kg/day based on 1 

ppm = 0.05 mg/kg/day)

NOAEL = 15 mg/kg/day

LOAEL= 150 mg/kg/day based on decreased body 

weight gain 

At the doses tested, there was not a treatment 

related increase in tumor incidence when compared 

to controls. Dosing was considered adequate.

870.4300 Chronic toxicity 

and 

carcinogenicity 

in mice 

40856503 and 

41337602

(1988)

acceptable/guideline

0, 1.35, 40.2, 408, and 

1156 mg/kg/day in 

males

1.72, 50.8, 512, and 

1386 mg/kg/day in 

females

NOAEL = 40.2 mg/kg/day

LOAEL= 408 mg/kg/day based on 

(i) increased mortality; (ii) decreased body weight 

gains; and (iii) kidney, liver, testes, teeth 

(hypoplasia), and bone toxicity.

Hepatocellular adenoma, carcinomas, and 

adenomas/carcinomas combined in both sexes at 2 

highest doses (408, and 1156 mg/kg/day). These 

doses were considered to be excessively toxic by 

the Cancer Peer Review Committee.

cancer classification: Group D
Primisulfuron-methyl D425535

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TABLE B.2.2 Subchronic, Chronic and Other Toxicity Profile for Primisulfuron-Methyl. 

Guideline

Number

Study Title MRID Number Results

870.5100 Gene Mutation -

bacterial

40331221 (1983)

acceptable/guideline

Salmonella 

typhimurium strains 

TA98, TA100, 

TA1535, and TA1537 

were exposed to 

primisulfuron methyl at 

concentrations of 1, 4, 

16, 64, or 256 μg/plate 

in the presence or 

absence of S9-

activation.

The test was negative.

No treatment-related increases in the number of 

revertants/plate were observed in any bacterial 

strain at any dose level of primisulfuron methyl up 

to cytotoxic levels in the presence or absence of S9-

activation.

870.5395 Cytogenetics In 

Vivo Mammalian 

Cytogenetics -

Erythrocyte 

Micronucleus 

assay in Chinese 

Hamsters

40331222 (1987) 

acceptable/guideline

Chinese hamsters 

(8/sex/dose/sample 

time) were dosed once 

via oral gavage (20 

mL/kg) with 

primisulfuron methyl at 

doses of. 0, 1250, 2500, 

or 5000 mg/kg. 

The test was negative.

Bone marrow cells were harvested at 16, 24, or 48 

hours post-dosing. There was no significant 

increase in the frequency of micronucleated 

polychromatic erythrocytes in bone marrow 

compared to controls.

870.5550 Unscheduled 

DNA Synthesis in 

Rat Hepatocytes/ 

Mammalian Cell 

Cultures

40331223 (1987) 

acceptable/guideline

Hepatocyte cultures 

from male RAIF (SPF) 

rats were exposed to 

primisulfuron methyl at 

concentrations of 2, 10, 

50, 100, 200, or 400 

μg/mL (Trial 1) and 

0.4, 2, 10, 20, 40, 60, 

80, 100, 200, or 400 

μg/mL (Trial 2).

The test was negative.

There was no evidence that unscheduled DNA 

synthesis, as determined by radioactive tracer 

procedures (nuclear silver grain counts), was 

induced.

870.7485 Metabolism and 

pharmacokinetics

40856502 and 

40856403

(1988)

acceptable/guideline

Rats were treated with 

[Pyrimidinyl-2-

14C] 

CGA-136872 or 

[Phenyl-U14C] CGA136872 as follows: (i) 

Group 1 received a 

single gavage dose at 

0.5 mg/kg; (ii) Group 2 

received a single oral 

dose at 500 mg/kg; (iii) 

Group 3 received 14 

daily oral doses of 

Recovery of radioactivity in the urine and feces: 

88.5-102% within 7 days.

At 0.5 mg/kg, (M: 23-31% dose in urine; 46-67% in 

feces) (F: 35.3-77% dose in urine; 13-48% in 

feces). At 500 mg/kg, 83-93% dose in feces in both 

sexes Tissues: 0.5% of dose at 7 days post-dose 

(highest in the liver).

Metabolic Pathway: Mainly hydroxylation of the 

pyrimidine ring to give rise to the 5-

hydroxyprimidinyl-CGA-136872 (i.e. CGA239769) followed by isomerization of the 

pyrimidinyl moiety. Bridge cleavage results in the 

formation of 2-carboxymethylbenzene sulfonamide 

in the feces and saccharin (a cyclization product) in 
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TABLE B.2.2 Subchronic, Chronic and Other Toxicity Profile for Primisulfuron-Methyl. 

Guideline

Number

Study Title MRID Number Results

unlabeled CGA-136872 

followed by an oral 

dose of [14C] CGA136872 (0.5 mg/kg) on 

Day 15; and (iv) Group 

4 received an i.v. dose 

at 0.5 mg/kg. 

the urine. The corresponding pyrimidinyl moiety is 

further metabolized.
Primisulfuron-methyl D425535

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Appendix C: Chemical Identity

Chemical Identity 

Common Name Primisulfuron methyl

IUPAC name methyl 2-[4,6-bis(difluoromethoxy)pyrimidin-2-

ylcarbamoylsulfamoyl]benzoate

CAS name methyl 2-[[[[[4,6-bis(difluoromethoxy)-2-

pyrimidinyl]amino]carbonyl]amino]sulfonyl]benzoate

PC Code 128973

CAS registry number 86209-51-0

Registration Review 

Case No. 

3034

Chemical Structure 
Primisulfuron-methyl D425535

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Appendix D: Dietary Exposure/Risk Modeling Inputs and Outputs

Filename: C:\Users\jlangsda\Documents\Chemicals\SUs\Primisulfuron-methyl\Dietary 

Assessment\Primisulfuron-methyl_Chronic.r08

Chemical: Primisulfuron-methyl 

RfD(Chronic): .25 mg/kg bw/day NOEL(Chronic): 0 mg/kg bw/day

RfD(Acute): 0 mg/kg bw/day NOEL(Acute): 0 mg/kg bw/day

Date created/last modified: 03-23-2015/11:30:33 Program ver. 3.16, 03-08-d

-----------------------------------------------------------------------------------

 EPA Crop Def Res Adj.Factors Comment

 Code Grp Commodity Name (ppm) #1 #2 

---------- ---- ------------------------------- ---------- ------ ------ -------

1500120000 15 Corn, field, flour 0.020000 1.000 1.000 

1500120001 15 Corn, field, flour-babyfood 0.020000 1.000 1.000 

1500121000 15 Corn, field, meal 0.020000 1.000 1.000 

1500121001 15 Corn, field, meal-babyfood 0.020000 1.000 1.000 

1500122000 15 Corn, field, bran 0.020000 1.000 1.000 

1500123000 15 Corn, field, starch 0.020000 1.000 1.000 

1500123001 15 Corn, field, starch-babyfood 0.020000 1.000 1.000 

1500124000 15 Corn, field, syrup 0.020000 1.500 1.000 

1500124001 15 Corn, field, syrup-babyfood 0.020000 1.500 1.000 

1500125000 15 Corn, field, oil 0.020000 1.000 1.000 

1500125001 15 Corn, field, oil-babyfood 0.020000 1.000 1.000 

1500126000 15 Corn, pop 0.020000 1.000 1.000 

3100044000 31 Beef, meat 0.100000 1.000 1.000 

3100044001 31 Beef, meat-babyfood 0.100000 1.000 1.000 

3100045000 31 Beef, meat, dried 0.100000 1.920 1.000 

3100046000 31 Beef, meat byproducts 0.100000 1.000 1.000 

3100046001 31 Beef, meat byproducts-babyfood 0.100000 1.000 1.000 

3100047000 31 Beef, fat 0.100000 1.000 1.000 

3100047001 31 Beef, fat-babyfood 0.100000 1.000 1.000 

3100048000 31 Beef, kidney 0.100000 1.000 1.000 

3100049000 31 Beef, liver 0.100000 1.000 1.000 

3100049001 31 Beef, liver-babyfood 0.100000 1.000 1.000 

3200169000 32 Goat, meat 0.100000 1.000 1.000 

3200170000 32 Goat, meat byproducts 0.100000 1.000 1.000 

3200171000 32 Goat, fat 0.100000 1.000 1.000 

3200172000 32 Goat, kidney 0.100000 1.000 1.000 

3200173000 32 Goat, liver 0.100000 1.000 1.000 

3300189000 33 Horse, meat 0.100000 1.000 1.000 

3400290000 34 Pork, meat 0.100000 1.000 1.000 

3400290001 34 Pork, meat-babyfood 0.100000 1.000 1.000 

3400291000 34 Pork, skin 0.100000 1.000 1.000 

3400292000 34 Pork, meat byproducts 0.100000 1.000 1.000 

3400292001 34 Pork, meat byproducts-babyfood 0.100000 1.000 1.000 

3400293000 34 Pork, fat 0.100000 1.000 1.000 

3400293001 34 Pork, fat-babyfood 0.100000 1.000 1.000 

3400294000 34 Pork, kidney 0.100000 1.000 1.000 

3400295000 34 Pork, liver 0.100000 1.000 1.000 

3500339000 35 Sheep, meat 0.100000 1.000 1.000 

3500339001 35 Sheep, meat-babyfood 0.100000 1.000 1.000 

3500340000 35 Sheep, meat byproducts 0.100000 1.000 1.000 

3500341000 35 Sheep, fat 0.100000 1.000 1.000 

3500341001 35 Sheep, fat-babyfood 0.100000 1.000 1.000 

3500342000 35 Sheep, kidney 0.100000 1.000 1.000 

3500343000 35 Sheep, liver 0.100000 1.000 1.000 

3600222000 36 Milk, fat 0.020000 1.000 1.000 

3600222001 36 Milk, fat-baby food/infant formu 0.020000 1.000 1.000 

3600223000 36 Milk, nonfat solids 0.020000 1.000 1.000 

3600223001 36 Milk, nonfat solids-baby food/in 0.020000 1.000 1.000 

3600224000 36 Milk, water 0.020000 1.000 1.000 

3600224001 36 Milk, water-babyfood/infant form 0.020000 1.000 1.000 

3600225001 36 Milk, sugar (lactose)-baby food/ 0.020000 1.000 1.000 

3800221000 38 Meat, game 0.100000 1.000 1.000 

3900312000 39 Rabbit, meat 0.100000 1.000 1.000 
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4000093000 40 Chicken, meat 0.100000 1.000 1.000 

4000093001 40 Chicken, meat-babyfood 0.100000 1.000 1.000 

4000094000 40 Chicken, liver 0.100000 1.000 1.000 

4000095000 40 Chicken, meat byproducts 0.100000 1.000 1.000 

4000095001 40 Chicken, meat byproducts-babyfoo 0.100000 1.000 1.000 

4000096000 40 Chicken, fat 0.100000 1.000 1.000 

4000096001 40 Chicken, fat-babyfood 0.100000 1.000 1.000 

4000097000 40 Chicken, skin 0.100000 1.000 1.000 

4000097001 40 Chicken, skin-babyfood 0.100000 1.000 1.000 

5000382000 50 Turkey, meat 0.100000 1.000 1.000 

5000382001 50 Turkey, meat-babyfood 0.100000 1.000 1.000 

5000383000 50 Turkey, liver 0.100000 1.000 1.000 

5000383001 50 Turkey, liver-babyfood 0.100000 1.000 1.000 

5000384000 50 Turkey, meat byproducts 0.100000 1.000 1.000 

5000384001 50 Turkey, meat byproducts-babyfood 0.100000 1.000 1.000 

5000385000 50 Turkey, fat 0.100000 1.000 1.000 

5000385001 50 Turkey, fat-babyfood 0.100000 1.000 1.000 

5000386000 50 Turkey, skin 0.100000 1.000 1.000 

5000386001 50 Turkey, skin-babyfood 0.100000 1.000 1.000 

6000301000 60 Poultry, other, meat 0.100000 1.000 1.000 

6000302000 60 Poultry, other, liver 0.100000 1.000 1.000 

6000303000 60 Poultry, other, meat byproducts 0.100000 1.000 1.000 

6000304000 60 Poultry, other, fat 0.100000 1.000 1.000 

6000305000 60 Poultry, other, skin 0.100000 1.000 1.000 

7000145000 70 Egg, whole 0.100000 1.000 1.000 

7000145001 70 Egg, whole-babyfood 0.100000 1.000 1.000 

7000146000 70 Egg, white 0.100000 1.000 1.000 

7000146001 70 Egg, white (solids)-babyfood 0.100000 1.000 1.000 

7000147000 70 Egg, yolk 0.100000 1.000 1.000 

7000147001 70 Egg, yolk-babyfood 0.100000 1.000 1.000 

8601000000 86A Water, direct, all sources 0.492000 1.000 1.000 

8602000000 86B Water, indirect, all sources 0.492000 1.000 1.000 

DEEM-FCID Chronic Results File

US EPA Ver. 3.16, 03-08-d

DEEM-FCID Chronic analysis for PRIMISULFURON-METHYL NHANES 2003-2008 2-day

Residue file name: C:\Users\jlangsda\Documents\Chemicals\SUs\Primisulfuron-methyl\Dietary 

Assessment\Primisulfuron-methyl_Chronic.r08

 Adjustment factor #2 used.

Analysis Date 03-23-2015/11:35:13 Residue file dated: 03-23-2015/11:30:33

Reference dose (RfD, Chronic) = .25 mg/kg bw/day

===============================================================================

 Total exposure by population subgroup

-------------------------------------------------------------------------------

 Total Exposure

 -----------------------------------

 Population mg/kg Percent of 

 Subgroup body wt/day Rfd 

-------------------------------------- ------------- ----------------

Total US Population 0.010704 4.3%

Hispanic 0.010323 4.1%

Non-Hisp-White 0.010980 4.4%

Non-Hisp-Black 0.008899 3.6%

Non-Hisp-Other 0.012305 4.9%

Nursing Infants 0.009507 3.8%

Non-Nursing Infants 0.034860 13.9%

Female 13+ PREG 0.010030 4.0%

Children 1-6 0.014352 5.7%

Children 7-12 0.009209 3.7%

Male 13-19 0.007518 3.0%

Female 13-19/NP 0.008262 3.3%

Male 20+ 0.009925 4.0%

Female 20+/NP 0.011081 4.4%

Seniors 55+ 0.010217 4.1%
Primisulfuron-methyl D425535

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All Infants 0.027032 10.8%

Female 13-50 0.010540 4.2%

Children 1-2 0.016319 6.5%

Children 3-5 0.013565 5.4%

Children 6-12 0.009683 3.9%

Youth 13-19 0.007893 3.2%

Adults 20-49 0.010595 4.2%

Adults 50-99 0.010422 4.2%

Female 13-49 0.010530 4.2%
Primisulfuron-methyl D425535

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Appendix E: Spray Drift Assessment for Primisulfuron-methyl

Off-target movement of pesticides can occur via many types of pathways and it is governed by a 

variety of factors. Sprays that are released and do not deposit in the application area end up offtarget and can lead to exposures to those it may directly contact. They can also deposit on 

surfaces where contact with residues can eventually lead to indirect exposures (e.g., children 

playing on lawns where residues have deposited next to treated fields). The potential risk 

estimates from these residues can be calculated using drift modeling onto 50 feet wide lawns 

coupled with methods employed for residential risk assessments for turf products.

The approach to be used for quantitatively incorporating spray drift into risk assessment is based 

on a premise of compliant applications which, by definition, should not result in direct exposures 

to individuals because of existing label language and other regulatory requirements intended to 

prevent them.7 Direct exposures would include inhalation of the spray plume or being sprayed 

directly. Rather, the exposures addressed here are thought to occur indirectly through contact 

with impacted areas, such as residential lawns, when compliant applications are conducted. 

Given this premise, exposures for children (1 to 2 years old) and adults who have contact with 

turf where residues are assumed to have deposited via spray drift thus resulting in an indirect 

exposure are the focus of this analysis analogous to how exposures to turf products are 

considered in risk assessment. 

In order to evaluate the drift potential and associated risks, an approach based on drift modeling 

coupled with techniques used to evaluate residential uses of pesticides was utilized. Essentially, a 

residential turf assessment based on exposure to deposited residues has been completed to 

address drift from the agricultural applications of primisulfuron-methyl. In the spray drift 

scenario, the deposited residue value was determined based on the amount of spray drift that may 

occur at varying distances from the edge of the treated field using the AgDrift (v2.1.1) model and 

the Residential Exposure Assessment Standard Operating Procedures Addenda 1: Consideration 

of Spray Drift Policy. Once the deposited residue values were determined, the remainder of the 

spray drift assessment was based on the algorithms and input values specified in the recently 

revised (2012) Standard Operating Procedures For Residential Risk Assessment (SOPs). 

A screening approach was developed based on the use of the AgDrift model in situations where 

specific label guidance that defines application parameters is not available.8,9 AgDrift is 

appropriate for use only when applications are made by aircraft, airblast orchard sprayers, and 

groundboom sprayers. When AgDrift was developed, a series of screening values (i.e., the Tier 

1 option) were incorporated into the model and represent each equipment type and use under 

varied conditions. The screening options specifically recommended in this methodology were 

selected because they are plausible and represent a reasonable upper bound level of drift for 

common application methods in agriculture. These screening options are consistent with how 

spray drift is considered in a number of ecological risk assessments and in the process used to 

develop drinking water concentrations used for risk assessment. In all cases, each scenario is to 

 

7 This approach is consistent with the requirements of the EPA’s Worker Protection Standard.

8http://www.agdrift.com/ 

9 Note that for many cases the scenarios outlined in the screening approach represent actual use practice so risk assessors should 

be aware and characterize these appropriately.
Primisulfuron-methyl D425535

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be evaluated unless it is not plausible based on the anticipated use pattern (e.g., herbicides are 

not typically applied to tree canopies) or specific label prohibitions (e.g., aerial applications are 

not allowed). The tables below provide the drift related risk estimates. 

In many cases, risks are of concern when the screening level estimates for spray drift are used as 

the basis for the analysis. In order to account for this issue and to provide additional risk 

management options additional spray drift deposition fractions were also considered. These drift 

estimates represent plausible options for pesticide labels. In the case of primisulfuron-methyl, 

there are no risks of concern at the edge of the field. 

Table E.1 Adult Risk Estimates (MOEs) Related to Indirect Exposure to Spray Drift for 

Primisulfuron-methyl for the Dermal Route of Exposure

Crop/Rate Group Spray Type/ Nozzle 

Configuration

Appl. Rate 

(lb ai/A) TTR (ug/cm2) At Edge

Corn and Bluegrass

Aerial

Fine to Medium

0.036 0.0040014

83,000

Medium to Coarse 100,000

Coarse to Very Coarse 120,000

Very Fine to Fine 57,000

AT401, M, 10 mph, 37% SD 91,000

WASP, M, 10 mph, 37% SD 98,000

AT401, C, 10 mph, 25% SD 110,000

WASP, C, 10 mph, 25% SD 120,000

AT401, VC, 10 mph, 20% SD 120,000

WASP, VC, 10 mph, 20% SD 150,000

Groundboom

High Boom Very fine to Fine 110,000

Low Boom Very fine to Fine 250,000

High Boom Fine to 

Medium/Coarse 430,000

Low Boom Fine to 

Medium/Coarse 650,000

Table E.2 Children (1<2 years old) Risk Estimates (MOEs) Related to Indirect Exposure to Spray 

Drift for Primisulfuron-methyl for the Dermal Routes of Exposure

Crop/Rate Group Spray Type/ Nozzle 

Configuration

Appl. Rate 

(lb ai/A) TTR (ug/cm2) At Edge

Corn and Bluegrass

Aerial

Aerial

0.036 0.0040014

49,000

Medium to Coarse 59,000

Coarse to Very Coarse 68,000

Very Fine to Fine 33,000

AT401, M, 10 mph, 37% SD 53,000

WASP, M, 10 mph, 37% SD 57,000
Primisulfuron-methyl D425535

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AT401, C, 10 mph, 25% SD 63,000

WASP, C, 10 mph, 25% SD 73,000

AT401, VC, 10 mph, 20% 

SD 71,000

WASP, VC, 10 mph, 20% 

SD 90,000

Groundboom

High Boom Very fine to 

Fine 67,000

Low Boom Very fine to Fine 150,000

High Boom Fine to 

Medium/Coarse 250,000

Low Boom Fine to 

Medium/Coarse 380,000

Table E.3 Children (1<2 years old) Risk Estimates (MOEs) Related to Indirect Exposure to Spray 

Drift for Primisulfuron-methyl for the Oral Routes of Exposure

Crop/Rate Group Spray Type/ Nozzle 

Configuration

Appl. Rate 

(lb ai/A) TTR (ug/cm2) At Edge

Corn and Bluegrass

Aerial

Aerial

0.036 0.0040014

350,000

Medium to Coarse 430,000

Coarse to Very Coarse 500,000

Very Fine to Fine 240,000

AT401, M, 10 mph, 37% SD 390,000

WASP, M, 10 mph, 37% SD 420,000

AT401, C, 10 mph, 25% SD 460,000

WASP, C, 10 mph, 25% SD 530,000

AT401, VC, 10 mph, 20% 

SD 520,000

WASP, VC, 10 mph, 20% 

SD 660,000

Groundboom

High Boom Very fine to 

Fine 490,000

Low Boom Very fine to Fine 1,100,000

High Boom Fine to 

Medium/Coarse 1,900,000

Low Boom Fine to 

Medium/Coarse 2,800,000
Primisulfuron-methyl D425535

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Appendix F. TTR and DFR Data Waiver Rationale

Turf Transferable Residue (TTR): In accordance with 40CFR158, TTR data are required for all 

occupational (e.g., sod farms, golf courses, parks, and recreational areas) or residential turf uses

that could result in post-application exposure to turf. In the absence of chemical-specific TTR 

data, EPA uses default values. The 2012 Standard Operating Procedures for Residential 

Pesticide Exposure Assessment includes an analysis of all TTR data, available at the time, which 

resulted in the selection of revised liquid and granular default values for the fraction of the 

application rate available for transfer after a turf application (FAR). These values are based on an 

analysis of 59 TTR studies performed with the Modified California Roller Method (36 studies 

using liquids, 11 studies using wettable powders/water dispersible granules, and 12 studies using 

granules). The liquid results (N=131) indicate a range of FAR values from 0.0005% to 6.1% and 

the granular results (N=37) indicate a range of 0.00064% to 0.69%. In both the liquid and 

granular data, a large range of transferability is observed and this variability can potentially be 

attributable to many factors such as active ingredient; formulation; field conditions in the studies; 

weather conditions (e.g., humidity); or many other difficult to quantify factors. Although 

witnessed across multiple chemicals, this range in FAR values is not expected when considering 

TTR data for a single chemical. HED selected 1% and 0.2% as high-end default values for 

liquid and granular products, respectively. Because TTR data are not available for 

primisulfuron-methyl, EPA is using the default value of [appropriate value for liquid or granular 

product]. Although there may be a small degree of uncertainty in the use of the default TTR 

value for primisulfuron-methyl (i.e., there is a small chance that the FAR value may exceed the 

applicable default value), it is likely that the health-protective aspects of EPA’s occupational

post-application turf assessment methodology will more than compensate for this potential 

uncertainty (i.e., the methodology is likely to overestimate exposure by a factor greater than the 

factor than the highest measured FAR values exceed the defaults ). For example, when assessing 

residential post-application turf exposure, EPA assumes the following: exposures occur to zeroday (i.e., day of application ) residues every day of the assessed exposure duration (i.e., EPA 

assumes that no dissipation or degradation occurs, it doesn’t rain, the grass is not mowed, etc); 

individuals perform the same post-application activities performed in the turf transfer coefficient 

study day after day (e.g., tumbling, playing on turf with toys, etc.); and individuals engage in 

these post-application activities for a high-end amount of time every day that is represented by 

data reflecting time children spend outdoors and not specifically engaged in activities on turf, 

when in actuality children do not spend all of their outdoor time on turf and high-end levels of 

activity will not occur every day.

Given the conservatisms discussed above and the potential compounding nature of these 

conservatisms, EPA is able to rely upon the calculated exposure estimates with confidence that 

exposure is not being underestimated. 

Since the estimated occupational post-application exposure for sod farms using default TTR 

values for primisulfuron-methyl is minimal in comparison to the level of concern (i.e., the 

calculated MOE is greater than 10 times higher than the level of concern, MOE = 110,000 

compared to the LOC of 100); EPA is waiving the 40CFR DFR data requirement. In this 

instance, it is unlikely that chemical-specific TTR data would be needed to further refine 
Primisulfuron-methyl D425535

Page 33 of 34

exposure assessments or would add appreciably to our overall understanding of the availability 

of turf transferable pesticide residues for primisulfuron-methyl. 

Dislodgeable Foliar Residue (DFR): In accordance with 40CFR158, DFR data are required for 

all occupational (e.g., crop, nursery, greenhouse use sites) or residential (e.g., ornamental and 

vegetable gardens, pick your own farms, retail tree farms) uses that could result in postapplication exposure to foliage. In the absence of chemical-specific DFR data, EPA uses default 

values. The 2012 Standard Operating Procedures for Residential Pesticide Exposure 

Assessment includes an analysis of a number of DFR studies, which resulted in the selection of a 

revised default values for the fraction of the application rate available for transfer after a foliar 

application (FAR). These values are based on an analysis of 19 DFR studies. Since that time, the 

Agricultural Re-entry Task Force has submitted information (MRID 49299201) that corrects an 

application rate error made in the original submission of “ARF039 – Determination of Dermal 

and Inhalation Exposure to Reentry Workers During Chrysanthemum Pinching in a Greenhouse” 

(EPA MRID 45344501). As a result, the range of FAR values was revised from 2% - 89% to 2% 

- 47%. In the data, a large range of transferability is observed and this variability can potentially 

be attributable to many factors such as active ingredient; formulation; field conditions in the 

studies; weather conditions (e.g., humidity); or many other difficult to quantify factors. 

Although witnessed across multiple chemicals, this range in FAR values is not expected when 

considering DFR data for a single chemical. At this time, the ARTF submission did not alter the 

selection of 25% as the reasonable, high-end default value. Because DFR data are not available 

for primisulfuron-methyl, EPA is using the default value of 25%. Although there may be a small 

degree of uncertainty in the use of the default DFR value for primisulfuron-methyl (i.e., there is a 

small chance that the FAR value may exceed the applicable default value), it is likely that the 

health-protective aspects of EPA’s occupational post-application assessment methodology will 

more than compensate for this potential uncertainty. For example, when assessing residential 

and occupational post-application exposure to gardens and ornamentals, EPA assumes the 

following: exposures occur to zero-day (i.e., day of application ) residues every day of the 

assessed exposure duration (i.e., EPA assumes that no dissipation or degradation occurs, it 

doesn’t rain, etc); individuals perform the same post-application activities performed in the 

transfer coefficient study day after day (e.g., weeding, harvesting, pruning, etc.); and individuals 

engage in these post-application activities for a high-end amount of time every day (represented 

by data reflecting time spent gardening based on survey data).

Given the conservatisms discussed above and the potential compounding nature of these 

conservatisms, EPA is able to rely upon the calculated exposure estimates with confidence that 

exposure is not being underestimated. 

Since the highest estimated occupational post-application exposure using default DFR values for 

primisulfuron-methyl is minimal in comparison to the level of concern (i.e., the calculated MOE 

is greater than 2 times higher than the level of concern, MOE = 15,000 compared to the LOC of 

100); EPA is waiving the 40CFR DFR data requirement. In this instance, it is unlikely that 

chemical-specific DFR data would be needed to further refine exposure assessments or would 

add appreciably to our overall understanding of the availability of dislodgeable foliar pesticide 

residues for primisulfuron-methyl. 
Primisulfuron-methyl D425535

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Appendix G: Review of Human Research

This risk assessment relies in part on data from studies in which adult human subjects were 

intentionally exposed to a pesticide or other chemical. These data are subject to ethics review 

pursuant to 40 CFR 26, have received that review, and are compliant with applicable ethics 

requirements. For certain studies 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/pesticides/science/handler-exposure-data.html and 

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