UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

Date: 09-MA Y-2013 

OFFICE OF 

CHEMICAL SAFETY AND 

POLLUTION PREVENTION 

SUBJECT: Ametryn. Human-Health Assessment Scoping Document in Support of 

Registration Review. 

DP Barcode: 0407652 

Registration No.: N/ A 

PC Code: 080801 

Decision No.: 473109 

Petition No.: N/ A 

Risk Assessment Type: N/ A 

TXRNo.: N/A 

Regulatory Action: Registration Review Scoping Document 

Case No.: 2010 

CAS No.: 834-12-8 

MRID No.: N/ A 40 CFR: § 180.258 

FROM: 

Chester 

Kelly M. 

E

Lowe, 

. Rodriguez, 

Senior 

Ph.D., 

Environmenta

Toxi~l 

l Scientist 

· ~GJ-~1.:~~~~ 

~ 

d-.'~ 

Sarah J. Levy, Chemist ~ Risk Assessment Branch 1 (RABl) 

Health Effects Division (HED, 7509P) 

THROUGH: Dana M. Vogel, Acting Branch Chief 

George F. Kramer, Ph.D., Senior Chemist 

RABl /HED (7509P) 

TO: Molly Clayton, Chemical Review Manager 

Pesticide Re-Evaluation Division (PRD) (7508P) 

___ .... . 

Attached is HED's human-health risk assessment scoping document for ametryn to support 

Registration Review. 

Page 1 of21 
~etryn Registration .Y ie~ uma~- ealth Assessm!nt Sc~pi g ocum nt 

Executive Summary 

Ametryn, N-eth yl-N' -(1-methylethyl)-6-(methylthio )-1 ,3 ,5-triazine-2,4-diamine, is a selective 

methylthiotriazine herbicide registered for use on com, pineapple, and sugarcane. There are no 

residential or non-agricultural uses registered for ametryn. There is currently one end-use 

product (EUP) containing ametryn as the active ingredient (ai) sold under the name Evik® DF 

(100-786). The final HED chapter of the ametryn Reregistration Eligibility Decision (RED) 

document was issued in 2005 (Memo, W. Donovan et al., 15-JUN-2005). There is one pending 

Special Local Needs (SLN) registration for ametryn (HI120004) for application to sugarcane 

(same rate as Section 3 registration with revised spray drift language), which was received in 

October of 2012. 

HED has evaluated the status of the human-health assessments for ametryn to determine whether 

sufficient data are available and whether any updates are needed to support Registration Review. 

HED has considered all available data and human-health risk assessments for ametryn with 

respect to its toxicity, exposure, and usage databases, and the most updated Agency science 

policy and risk assessment methodologies to determine the scope of work necessary to support 

Registration Review. 

The available toxicity database for ametryn indicates that the liver is a target organ of toxicity 

and the dog is the most sensitive species. In a dog chronic-toxicity study, reported effects 

included histopathological findings consistent with degenerative liver lesions. In the rat, 

histopathological findings were reported in the kidney, testes, liver, and pancreas, but at higher 

administered doses compared to the dog. Prenatal developmental toxicity studies in rats and 

rabbits and a rat reproductive toxicity study do not indicate increased pre- or postnatal 

susceptibility following ametryn exposure. Neither prenatal developmental toxicity study 

revealed offspring effects and the rat reproductive toxicity study only showed body-weight 

decrements at the same dose as similar maternal toxicity. In the final HED chapter of the 

ametryn RED (Memo, W. Donovan et al, 15-JUN-2005, 0 316695), it was determined that 

dosing in a rat carcinogenicity study was adequate for carcinogenicity assessment. The results 

indicated that that there was no indication of treatment-related increased incidence of tumors in 

the absence of excessive body-weight loss. In a mouse carcinogenicity study, there was also no 

indication of treatment-related tumors at any dose. Therefore, a quantitative cancer risk 

assessment was deemed not necessary. In acute toxicity studies, ametryn was classified as 

having low acute toxicity via by the oral, dermal, and inhalation routes (Toxicity Category III or 

IV). It was found to cause mild eye irritation, but it was neither a dermal irritant nor a dermal 

sensitizer. The current toxicity database for ametryn lacks a 28-day inhalation toxicity, 

neurotoxicity (acute and subchronic), and immunotoxicity studies according to the 2007 revised 

40 CFR data requirements. The HED's Hazard and Science Policy Council (HASPOC) has 

determined that the neurotoxicity studies are not required at this time; however, a 28-day 

inhalation toxicity study and an immunotoxicity study are required. 

The residue chemistry database is adequate to support current Registration Review requirements. 

Adequate metabolism (crops, livestock, and rotational crops), storage stability, magnitude of the 

residue, and processing data are available to support the registered uses. Adequate methods are 

available for enforcement of the currently established tolerances. 

The dietary-exposure database is adequate to support current registration requirements. The last 

risk assessment provided chronic dietary (food only) exposure estimates that are below HED's 

level of concern (LOC) for the general U.S. population and all population subgroups (Memo, W. 

Page 2 of21 
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Donovan, 24-MAY-2005; D316934). Chronic dietary (food only) risk estimates were less than 

<1.0% of the chronic population-adjusted dose (cPAD). As part of Registration Review, a 

revised dietary exposure analysis will be required to reflect current Agency policy (incorporating 

both food and water exposures), the most recent dietary-exposure models, and any potential 

changes to the toxicological points of departure (PODs). 

There is sufficient information available to assess occupational and residential exposure and risk 

from the registered uses. There are no residential uses currently registered for ametryn; 

therefore, a quantitative residential exposure/risk assessment is not necessary during Registration 

Review. The previous occupational handler assessment covered the relevant exposure scenarios 

and did not result in risk estimates of concern. Revised occupational handler assessments will be 

required during Registration Review to include revised surrogate unit exposures for occupational 

handlers1. An occupational post-application assessment was not conducted previously based on 

(1) the use directions to avoid contacting foliage and (2) the timing of applications (early 

season). A quantitative occupational post-application assessment will not be necessary during 

Registration Review.

The following data deficiencies were identified for ametryn:

Toxicology: 

o 870.7800: Immunotoxicity Study

o 870.3465: 90-day Inhalation study2

Residue Chemistry:

o None. 

Dietary Exposure: 

o None.

Occupational/Residential Exposure: 

o None.

EPA anticipates conducting the following risk assessment updates during Registration Review:

Toxicology: 

o Reevaluate toxicity endpoint/dose selection, along with the Food Quality 

Protection Act (FQPA) Safety Factor (SF), based on submitted studies and any 

outstanding data needs.

Residue Chemistry: 

o The tolerance expression should be changed to conform to current HED policy 

(see Section 9.0 of this document for details).

Dietary Exposure: 

o A revised dietary risk assessment will be necessary to reflect current Agency 

policy (incorporating both food and water exposures), the most recent dietary 

exposure models, and any potential changes to the toxicological PODs. 

Occupational/Residential Exposure: 

o A revised occupational handler risk assessment will be necessary to reflect the 

 

1 Outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” available at 

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

2

28-day inhalation study will be sufficient.
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most recent occupational handler surrogate exposure data3and current Agency 

policies.

Aggregate Exposure:

o A revised aggregate exposure assessment will be necessary to reflect the latest 

Agency policy [the drinking water level of comparison (DWLOC) approach has 

been superseded], a new dietary assessment (incorporating both food and water 

exposures), and any potential changes to the ametryn toxicological PODs. 

1.0 Introduction

Ametryn is a selective methylthiotriazine herbicide registered for use on corn, pineapple, and 

sugarcane. There are no residential uses registered for ametryn. There is currently one EUP

with ametryn as the ai, Evik® DF (100-786). This product is a dry-flowable (DF) formulation

containing 78.9% ai. The final HED chapter of the ametryn RED document was issued in 2005 

(Memo, W. Donovan et al., 15-JUN-2005, D316695). This is the most recent human-health risk 

assessment for ametryn. There is one pending SLN registration for ametryn (HI120004; 

sugarcane), which was received in October of 2012. This memo only evaluates the status of the 

human-health assessments for ametryn.

2.0 Hazard Characterization/Assessment

Ametryn is a methylthiotriazine herbicide. It is a member of the triazine family of herbicides

and its mode of action involves inhibition of photosynthesis. Some of the toxic effects reported 

in mammals involving body-weight decrements are consistent with a similar metabolismdisrupting mode of action. 

Toxicity Database

Based on the new guidelines as specified in 40 CFR Part 158 requirements, the following studies 

are currently missing in the ametryn toxicity database: neurotoxicity (acute and subchronic), 

immunotoxicity, and potentially a 28-day inhalation toxicity study. The HASPOC met on 

January 17, 2013 (TXR #0056557) to decide on the missing studies for ametryn. In the case of 

the missing neurotoxicity studies, the committee determined that the acute and subchronic 

neurotoxicity studies are not required at this time. In the absence of an acute neurotoxicity study 

(870.6200), the rat prenatal developmental toxicity study where maternal clinical signs,

consisting of ptosis and salivation, were observed after approximately two days of dosing will be 

used for the acute dietary endpoint of the general U.S. population. With regard to the 

immunotoxicity requirement, EPA’s Office of Pesticide Programs (OPP) has published the 

findings of an independent retrospective analysis of 170 immunotoxicity studies submitted to the 

Agency. The retrospective analysis suggests that the submitted immunotoxicity studies have not 

yet resulted in PODs that are lower than the PODs selected from other available guideline 

experimental toxicology studies. As a result, the currently available immunotoxicity studies 

have not impacted the Agency’s risk assessments. HED is in the process of developing a 

guidance document on data waiver considerations. In the interim, HED recommends that 

immunotoxicity studies continue to be required for registration and registration review 

chemicals. Lastly, the committee determined that a 28-day rat inhalation toxicity study 

(870.3465) was required for ametryn. The decision was primarily based on the low margin of 

exposure (MOE) estimates when an oral POD is used for assessing occupational inhalation risk.

 

3 Outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” available at 

http://www.epa.gov/pesticides/science/handler-exposure-data.html
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Adsorption, Distribution, Metabolism, and Excretion (ADME)

In rats, radiolabeled ametryn was readily absorbed into the systemic circulation when 

administered as a single dose or multiple doses via oral gavage to rats. Based on the amount of 

radioactivity collected in urine (the primary clearance pathway), the fraction absorbed was 

estimated at 50-60%. There was extensive metabolism of ametryn to hydrophilic residues. The 

radiolabel was widely distributed, although tissue levels were relatively low. Based on urinary 

and fecal excretion profiles, excretion primarily occurred in the first 48 hours. 

Toxicological Effects

In acute toxicity studies, ametryn was classified as having low acute toxicity via by the oral, 

dermal, and inhalation routes (Toxicity Category III or IV). It was found to cause mild eye 

irritation, but it was neither a dermal irritant nor a dermal sensitizer.

The available toxicity database for ametryn indicates that the liver is a target organ of toxicity 

and the dog is the most sensitive species. In a dog chronic toxicity study, reported effects were 

histopathological findings indicative of degenerative liver lesions including inflammation 

(granulomatous, purulent, and lymphocytic), isolated cellular necrosis, endogenous pigment 

deposition, vacuolar degeneration, and bile duct hyperplasia. At higher dose levels, there were 

also clinical signs consisting of ataxia, cachexia, coma, convulsions, hypersensitivity to touch, 

hypoactivity, hypotonia, pallor, tremors, and unkempt appearance. In the rat, toxicity reported at 

higher administered levels of ametryn compared to the dog, consisted of body weight and bodyweight gain decreases and histopathological lesions in the kidney (mineralization in the renal 

pelvis), testes (interstitial hyperplasia), pituitary (hyperplasia), liver (hyperplasia), and pancreas 

(hyperplasia).

Prenatal developmental toxicity studies in rats and rabbits and a rat reproductive toxicity study 

do not indicate increased pre- or postnatal susceptibility following ametryn exposure. Maternal 

effects in the rat study were limited to ptosis and salivation, while in rabbits, maternal effects 

were based on decreased body weight, feed consumption, and increased liver weight. Neither 

prenatal developmental toxicity study revealed offspring effects. In a rat two-generation 

reproductive toxicity study, offspring body weight and body-weight gain decrements were 

reported at the same dose as similar maternal effects (i.e., decreased body weight/body-weight

gain and feed efficiency).

In a rat carcinogenicity study, at the highest average daily doses tested of 145.3 and 176.1 

mg/kg/day for males and females, respectively, there was a significant increase in tumors in the 

testes, epididymis, and thyroid in males and both the liver and mammary gland in females. 

However, these effects were accompanied by excessive decrements in body weight and bodyweight gain. At the next lower dose of 500 ppm, there was no effect on body weight reported,

and there were no tumors seen. In 2004, the HED Cancer Assessment Review Committee 

(CARC) evaluated the study findings and determined that the data was inadequate for assessment 

of human carcinogenic potential and requested for a new rat carcinogenicity study to be 

conducted (TXR# 0052862). In 2005, HED conducted a re-analysis of the body-weight data for 

the 500 ppm group in conjunction with a more recent 90-day subchronic study (MRID# 

46467501) submitted by the registrant. The results indicated that there was a consistently lower 

body weight of 3-7% for males for most of the duration and a comparable body-weight decrease 

for females for most of the first 90 days of dosing. Since the body-weight decrements at 500 

ppm were now deemed adequate for carcinogenicity assessment and there was no indication of 

treatment-related increased incidence of tumors at this lower dose, a quantitative risk assessment 

was deemed not necessary and a new rat carcinogenicity study not required (D316605, W. 
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Donovan et al., 15-JUN-2005). The decision for not requiring a new rat carcinogenicity study 

was supported by additional information from closely related s-triazines: prometryn and 

terbutryn. The cancer studies with these structurally related chemicals support the notion that 

either tumor are not seen at all at dose tested (prometryn) or are seen (terbutryn) at doses where 

body weight is drastically affected. The Agency’s Science Advisory Panel (SAP) evaluated the 

carcinogenicity data for terbutryn and determined that quantitative cancer risk assessment was 

not required (SAP meeting, 23-DEC-1987). In a mouse carcinogenicity study, there were no 

treatment-related tumors seen in males or females at any dose.

In the last HED chapter of the ametryn RED (Memo, W. Donovan et al., 15-JUN-2005, 

D316695), a forward gene-mutation assay in mammalian cell cultures was noted as a missing 

data requirement. Since then, a mouse lymphoma cells/mammalian activation gene forward 

mutation assay has been submitted and reviewed by the Agency. The results of the study are in 

agreement with other genotoxicity assays indicating that there is no evidence of genotoxicity for 

ametryn.

Ametryn was not included in the cumulative risk assessment performed for triazines that 

included atrazine, simazine, and propazine because it does not cause the same carcinogenic 

profile as these chlorotriazines, and there is no mechanistic information that would support 

including it in this group.

There is no dermal penetration study or inhalation toxicity study based on repeated exposures to 

ametryn. In the last risk assessment, a dermal-absorption factor of 6% was indirectly estimated 

based on the no-observed adverse-effect level (NOAEL) of the rabbit prenatal developmental 

toxicity study and that from a 21-day rabbit dermal toxicity study. The rabbit developmental 

toxicity study based on oral exposure was also used for assessing short- and intermediate-term 

occupational inhalation endpoints.

Conclusions: Based on the new guidelines as specified in 40 CFR Part 158 requirements, the 

following studies are currently missing in the ametryn toxicity database: neurotoxicity (acute 

and subchronic), immunotoxicity, and a 28-day inhalation toxicity study. The HASPOC 

determined that while the neurotoxicity studies (acute and subchronic) are not needed at this 

time, a 28-day rat inhalation toxicity study (870.3465) is required for ametryn. HED is in the 

process of developing a guidance document on data waiver considerations for immunotoxicity 

studies. In the interim, HED recommends that immunotoxicity studies continue to be required 

for registration and registration review chemicals. During Registration Review, the endpoints, 

doses, and safety factors used in the most recent human-health risk assessments should be 

reconsidered based on current HED policy, recently submitted studies, and any other outstanding 

data.

3.0 Residue Chemistry

Permanent tolerances are established for residues of ametryn per se in/on field corn grain and 

stover, pop corn grain and stover, pineapple, and sugarcane commodities at 0.50 ppm, as well as 

a tolerance for corn forage at 0.1 ppm [40 CFR §180.258]. There are currently no tolerances for 

ametryn residues in livestock commodities or for inadvertent residues in rotational crops.

The nature of the residue in primary crops and livestock is adequately understood based on the 

available corn, sugarcane, banana, goat, and hen metabolism studies. In plants, ametryn is 

extensively metabolized by N-dealkylation and desulfation (oxidation/hydroxylation) to a variety 
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of triazine ring containing metabolites. The metabolism of ametryn in livestock also involves Ndealkylation of the isopropyl and ethyl side chains, as well as modification at the 6-position, 

followed by conjugation, with the triazine ring structure remaining intact. The regulated residues 

in plant commodities consist of ametryn per se. The residues of concern for tolerance 

enforcement and risk assessment (food only) also consist of ametryn per se.

Adequate field trial data are available to support the use of ametryn on corn (field and pop), 

pineapples, and sugarcane. An adequate number of trials were conducted in the appropriate 

geographical regions using the appropriate formulation applied at the maximum use rate. These 

studies are also supported by adequate storage stability data. The available processing studies 

for corn, pineapple, and sugarcane are adequate and indicate that residues of ametryn and its 

three thiomethyl metabolites are not likely to be quantifiable ( 0.02 ppm) in corn, pineapple, or 

sugarcane processed fractions derived from crops treated at the maximum labeled rates. 

Adequate methods are available for enforcing tolerances and/or collecting data on ametryn 

residues in/on plant and livestock commodities. Two gas chromatography (GC) methods are 

available for enforcing tolerances of ametryn in plant commodities and are listed as Methods I 

and A in the Pesticide Analytical Method Volume II (PAM II; Section 180.258). Method I is a 

GC/microcoulometric (MC) detection method for determining ametryn per se, with a limit of 

quantitation (LOQ) of 0.05 ppm. Method A is a GC/flame-photometric detection (sulfur mode, 

FPD-S) method for determining residues of ametryn and its three thiomethyl metabolites (GS11354, GS-11355, and GS-26831), with a LOQ of 0.05 ppm for parent and 0.1 ppm for each 

metabolite.

Considering the data from the available livestock metabolism and feeding studies and the 

calculated maximum theoretical dietary burdens (MTDBs) of 0.15-0.18 ppm for cattle and 0.04 

ppm for poultry and swine, HED concludes that there is no reasonable expectation of 

quantifiable residues of ametryn occurring in livestock commodities [40 CFR §180.6(a)(3)]. 

Therefore, tolerances for livestock commodities are not required at the present time.

An adequate confined rotational crop study is available and indicates that the metabolism in 

rotational crops is similar to the primary crops. Adequate field rotational crop studies are also 

available and indicate that the labeled plant back intervals are appropriate and rotational crop 

tolerances are not required. 

Conclusions: The residue chemistry database is adequate to support current Registration Review 

data requirements. Adequate metabolism (crops, livestock, and rotational crops), storage 

stability, magnitude of the residue and processing data are available to support the registered 

uses. Adequate methods are available for enforcement of the currently established tolerances. 

4.0 Dietary Exposure

In the 2005 chronic dietary exposure assessment for the ametryn RED, HED conducted chronic 

dietary exposure analyses for all currently registered food uses of ametryn (Memo, W. Donovan, 

D316934, 24-MAY-2005). Acute dietary exposure analyses were not conducted since no acute 

endpoint was chosen for ametryn. The chronic dietary analyses were conducted using both the 

Dietary Exposure Evaluation Model – Food Consumption Intake Database (DEEM-FCID, ver. 

2.0) model, as well as the Lifeline (ver. 2.0) model. Both models incorporated the food 

consumption data from the United States Department of Agriculture (USDA) Continuing 

Surveys of Food Intakes by Individuals (CSFII; 1994-1996 and 1998) and assumed average 
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residue levels from applicable field trials, percent crop treated information, and DEEM (ver. 

7.76) default processing factors. The chronic dietary assessments from both models show 

dietary (food only) risk estimates were less than 1.0% of the cPAD and were below HED’s LOC

(i.e., <100% of the cPAD). 

In the 2005 HED chapter of the ametryn RED (Memo, W. Donovan et al., 15-JUN-2005, 

D316695), exposure to ametryn in drinking water was also assessed. Water models were used to 

assess potential exposure to ametryn from consumption of contaminated drinking water. 

Estimated drinking water concentrations (EDWCs) for ametryn were generated using the

Pesticide Root Zone Model/Exposure Analysis Modeling System (PRZM/EXAMS) for surface 

water and the Screening Concentration in Ground Water (SCI-GROW) 2 model for groundwater. 

The ametryn EDWCs were not incorporated into the dietary exposure assessment in the RED, 

but were compared to calculated DWLOCs for the aggregate assessment (see Section 6 below). 

Potential contaminants of concern considered in the drinking water exposure assessment were 

parent ametryn and the degradates 2-amino-4-isopropylamino-6-methylthio-s-triazine (GS11354), 2-ethylamino-4-amino-6-methylthio-s-triazine (GS-11355), NOA-423271, and NOA428383. Based on input from EFED on the environmental transformation products of ametryn, 

HED does not anticipate any changes to the residues of concern identified for ametryn. The 

modeled EDWCs for ametryn were 14 ppb for surface water and 1.4 ppb for groundwater. It is 

unlikely that updated drinking water estimates will be required during Registration Review. 

Conclusions: The dietary-exposure database is adequate to support current Registration Review 

requirements. The chronic dietary assessments from both models show dietary (food only) risk 

estimates were less than 1.0% of the cPAD and were, therefore, below HED’s LOC (i.e., <100% 

of the cPAD). As part of Registration Review, revised dietary exposure analyses will be 

required to reflect current Agency policy (incorporating both food + water exposures), the most 

recent dietary exposure models, and any potential changes to the toxicological PODs. 

5.0 Residential Exposure

The registered uses for ametryn are not expected to result in residential exposure; therefore, a 

quantitative residential exposure assessment has not been conducted and will not be required for 

Registration Review.

Spray Drift

Residential exposures resulting from off-site transport (e.g., spray drift or volatilization) may 

occur as a result of applications of ametryn. The Agency is in the process of evaluating these 

types of exposures and may, as appropriate, develop policies and procedures to identify the need 

for and, subsequently, the way to incorporate these post-application exposures into the Agency's 

risk assessments. The need for spray drift and volatilization risk assessment for ametryn will be 

examined during Registration Review.

Conclusions: There are no residential uses currently registered for ametryn; therefore, a 

quantitative residential exposure/risk assessment is not necessary during Registration Review.

6.0 Aggregate-Risk Assessment

The most recent aggregate-risk assessment was performed in conjunction with the 2005 HED 

chapter of the ametryn RED conducted by HED (Memo, W. Donovan et al., 15-JUN-2005, 

D316695). Since there were no registered residential uses for ametryn or an acute endpoint, only 
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a chronic aggregate assessment was conducted utilizing the DWLOC approach. DWLOCs 

represent aggregate exposure from food and drinking water, and were compared to the modeled

EDWCs for surface and ground water to determine whether aggregate chronic risks were of 

concern. All EDWCs were less than HED’s calculated chronic DWLOCs. Therefore, chronic 

aggregate exposures to ametryn in food and drinking water were not of concern from a risk 

perspective. 

Conclusions: A new aggregate risk assessment will be required during Registration Review to 

incorporate the latest Agency policy (the DWLOC approach has been superseded), a new dietary 

assessment (incorporating both food and water exposures), and any potential changes to the 

ametryn toxicological PODs. 

7.0 Occupational Exposure

Occupational handler and post-application exposures are expected based on the registered

agricultural uses of ametryn. Attachment 4 provides a summary of the occupational use pattern. 

The current registered formulation is a DF product, with application rates ranging from 1.2-2.4

pounds active ingredient per acre (lb ai/A). 

Occupational Handlers

There is the potential for dermal and inhalation exposure to occupational handlers from the 

currently registered use pattern of ametryn. In all past risk assessments, no chemical-specific 

data were available with which to assess potential exposure to pesticide handlers; therefore, 

occupational handler assessments were based primarily on surrogate unit exposures from the 

Pesticide Handlers Exposure Database (PHED). Previous risk calculations were based on the 

maximum application rates and assuming maximum area treated per day. Handler's exposure 

and risk were calculated at baseline (long pants, a long-sleeved shirt, no chemical-resistant

gloves, and no respirator) and with personal-protective equipment (PPE) when necessary (e.g., 

chemical-resistant gloves, respirators, and engineering controls). 

In the 2005 HED chapter of the ametryn RED (Memo, W. Donovan et al., 15-JUN-2005, 

D316695), occupational handler scenarios were assessed for DF formulations at rates ranging 

from 1.2-2.4 lb ai/A. A total MOE (dermal + inhalation) was presented along with route-specific 

MOEs. None of the scenarios assessed resulted in risk estimates of concern (i.e., all MOEs ≥ 

100; total MOEs (dermal + inhalation) ranged from 230 to 57,000). Based on existing 

registrations, the previous assessments identified all of the anticipated occupational handler 

exposure scenarios. The occupational handler scenarios may need to be reassessed to address 

updates to HED’s exposure policies, including updates to default exposure data used for handler 

scenarios and assumptions for body weights. 

Occupational Post-Application

There may be the potential for post-application dermal exposure to workers following 

applications of ametryn to agricultural crops. However, the labels indicate that most applications 

are to be made as directed sprays, avoiding the crop foliage. For sugarcane, the product label 

appears to allow for over-the-top applications, but based on crop profile information for 

sugarcane, weed control is most important during the early growth stages, when the crop height 

is low and there is minimal foliage4. Therefore, it is not anticipated that there will be significant 

worker exposure to foliar residues following applications.

 

4 Weed Management in Sugarcane. D.C. Odero and J.A. Dusky. http://edis.ifas.ufl.edu/wg004
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The 2005 HED chapter of the ametryn RED (Memo, W. Donovan et al., 15-JUN-2005, 

D316695) came to a similar conclusion noting the following: (1) ametryn product labeling 

specifies application as either a directed spray at weeds or as a preemergent broadcast spray, (2) 

the label includes instructions to avoid application to the crop foliage, (3) the label specifies the 

last ametryn application be made 30 and 160 days prior to harvesting for corn and pineapples, 

respectively, and (4) the label specifies “Avoid wetting sugarcane foliage, or injury may occur” 

for sugarcane, and also recommends against application after “close-in” - when the sugarcane 

grows over the planting beds prior to harvesting. For these reasons, HED did not anticipate any 

foliar residues on the ametryn treated crops, and did not quantitatively assess post-application 

occupational exposures. 

Conclusions: The occupational exposure database is adequate to support the Registration 

Review process for ametryn. The previous occupational handler assessment covered the relevant 

exposure scenarios and did not result in risk estimates of concern. Revised occupational handler 

assessments will be required during Registration Review to include revised surrogate unit 

exposures for occupational handlers5. An occupational post-application assessment was not 

conducted previously based on (1) the use directions to avoid contacting foliage and (2) the 

timing of applications (early season). A quantitative occupational post-application assessment 

will not be necessary during Registration Review.

8.0 Public Health and Pesticide Epidemiology Data

The Agency has reviewed the available incident data for ametryn (Memo, S. Recore and E. 

Evans, D407648, 31-JAN-2013) and concludes that based on the low frequency and severity of 

incident cases reported for ametryn, there does not appear to be a concern at this time that would 

warrant further investigation. The Agency will continue to monitor the incident information and 

if a concern is triggered, additional analysis will be included in the risk assessment.

9.0 Tolerance Assessment and International Harmonization

The tolerance expression should be changed to conform to current HED policy. Specifically, the 

tolerance expression for 40 CFR §180.258(a) should be as follows:

"Tolerances are established for residues of the herbicide ametryn, including its metabolites and 

degradates, in or on the commodities listed in the following table. Compliance with the 

tolerance levels specified in the table is to be determined by measuring only ametryn, N-ethyl-N′-

(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine), in or on the following commodities."

U.S. permanent tolerances (listed in 40 CFR §180.258) are summarized in Attachment 5. There 

are no Codex or Mexican maximum residue limits (MRLs) in/on the U.S. registered crops. 

 

10.0 Environmental Justice

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

most recent Ametryn human-health risk assessment, in accordance with U.S. Executive Order 

12898, “Federal Actions to Address Environmental Justice in Minority Populations and Low-

 

5 Outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” available at 

http://www.epa.gov/pesticides/science/handler-exposure-data.html
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Income Populations6.” The OPP typically considers the highest potential exposures from the 

legal use of a pesticide when conducting human-health risk assessments, including, but not 

limited to, people who obtain drinking water from sources near agricultural areas, the variability 

of diets within the U.S., and people who may be exposed when harvesting crops. Should these 

highest exposures indicate potential risks of concern, OPP further refines the risk assessments to 

ensure that the risk estimates are based on the best available information.

11.0 Cumulative 

Ametryn is a triazine, and certain triazine pesticides were identified as a common-mechanism 

group (CMG) by the Agency in a 2002 paper entitled, “The Grouping of a Series of Triazine 

Pesticides Based on a Common Mechanism of Toxicity.7” However, ametryn was excluded 

from the triazine CMG because it does not share the toxicity profile of the CMG triazines. For 

the purposes of this action, therefore, EPA has assumed that ametryn does not have a common 

mechanism of toxicity with other substances. 

12.0 Endocrine Disruption

As required by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the Federal 

Food, Drug, and Cosmetic Act (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

that 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 chronic studies that assess growth, developmental and reproductive effects in 

different taxonomic groups. As part of its most recent registration decision, 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), ametryn 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. Ametryn is not 

 

6

http://www.hss.energy.gov/nuclearsafety/env/guidance/justice/eo12898.pdf

7

http://www.epa.gov/oppsrrd1/REDs/triazine_cumulative_risk.pdf
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among the group of 58 pesticide active ingredients on the initial list to be screened under the 

EDSP. Accordingly, as part of Registration Review, EPA will issue future EDSP orders/data 

call-ins, requiring the submission of EDSP screening assays for ametryn. For further 

information on the status of the EDSP, the policies and procedures, the list of 67 chemicals, 

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

http://www.epa.gov/endo/.

13.0 Human Studies

Past ametryn risk assessments rely in part on data from studies in which adult human subjects 

were intentionally exposed to a pesticide to determine their dermal and inhalation exposure. 

Many such studies, involving exposure to many different pesticides, comprise generic pesticide 

exposure databases such as PHED, the Outdoor Residential Exposure Task Force (ORETF)

Database, and the Agricultural Reentry Task Force (ARTF) Database. EPA has reviewed all the 

studies supporting these multi-pesticide generic exposure databases, and has found no clear and 

convincing evidence that the conduct of any of them was either fundamentally unethical or 

significantly deficient relative to the ethical standards prevailing at the time the research was 

conducted. All applicable requirements of EPA’s Rule for the Protection of Human Subjects of 

Research (40 CFR Part 26) have been satisfied, and there is no regulatory barrier to continued 

reliance on these studies.

14.0 Risk Assessment Updates, Data Deficiencies, and Label Revisions

The following data deficiencies were identified for ametryn:

Toxicology: 

o 870.7800: Immunotoxicity Study

o 870.3465: 90-day Inhalation study8

Residue Chemistry:

o None. 

Dietary Exposure: 

o None.

Occupational/Residential Exposure: 

o None.

EPA anticipates conducting the following risk assessment updates during Registration Review:

Toxicology: 

o Reevaluate toxicity endpoint/dose selection, along with the FQPA SF, based on 

submitted studies and any outstanding data.

Residue Chemistry: 

o The tolerance expression should be changed to conform to current HED policy 

(see Section 9.0 of this document for details).

Dietary Exposure: 

o A revised dietary risk assessment will be necessary to reflect current Agency 

policy (incorporating both food and water exposures), the most recent dietary 

exposure models, and any potential changes to the toxicological PODs.

Occupational/Residential Exposure: 

 

8

28-day inhalation study will be sufficient.
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o Revised occupational handler risk assessments will be necessary to reflect the 

most recent occupational handler surrogate exposure data9and current Agency 

policies.

Aggregate Exposure:

o A revised aggregate exposure assessment will be necessary incorporating the 

latest Agency policy (the DWLOC approach has been superseded), a new dietary 

assessment (incorporating both food and water exposures), and any potential 

changes to the ametryn toxicological PODs. 

 

9 Outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” available at 

http://www.epa.gov/pesticides/science/handler-exposure-data.html
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15.0 References

Table 1. Memoranda Relevant to Registration Review1.

Author Barcode Date Title

W. Donovan et 

al.

D316695 15-JUN-2005 

Revised Memo to Incorporate Responses to Phase 3 Public 

Comments. Ametryn: HED Chapter of the Reregistration 

Eligibility Decision Document (RED). PC Code: 080801, 

Case #: 2010, DP Barcode: D316695.

R. Travaglini D 318295 13-JUN-2005

Corrected Ametryn ORE Chapter to Incorporate Responses 

to Phase 3 Public Comments- Ametryn. HED Occupational 

and Residential Exposure Chapter of the Reregistration 

Eligibility Decision Document.

1. This table only includes references to final versions. Previous versions of these documents are available, but have been superseded.

Attachments: 

Attachment 1: Chemical Identity Table.

Attachment 2: Ametryn Acute, Subchronic, and Chronic Toxicity Profile

Attachment 3: Ametryn Endpoint Selection Tables.

Attachment 4: Summary of Occupational Registered Uses Pulled From LUIS Report 

(dated 8/22/12).

Attachment 5: Ametryn International Residue Limit Status Sheet.

cc: K. Lowe (RAB1), S. Levy (RAB1), C. Rodriguez (RAB1)

RDI: RAB1 (2/20/13), D. Vogel (2/20/13), J. Rowland (2/20/13)

K.Lowe:S10947:PY-S:(703)347-8989:7509P:RAB1
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Attachment 1: Chemical Identity Table.

Chemical Structure and Nomenclature for Ametryn and its Thiomethyl Metabolites.

Chemical structure

Common name Ametryn

Molecular Formula C9H17N5S

Molecular Weight 227.35

IUPAC name N

2

-ethyl-N

4

-isopropyl-6-methylthio-1,3,5-triazine-2,4-diamine

CAS name N-ethyl-N -(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine

CAS # 834-12-8

PC Code 080801

Food/Feed Site Registration Field Corn, Pineapple, and Sugarcane

Chemical structure

Common name NA

Company experimental name GS-11354; CG-3

IUPAC name NA

CAS name N-isopropyl-6-(methylthio)-1,3,5-triazine-2,4-diamine

CAS registry number 4147-57-3

Chemical structure

Common name NA

Company experimental name GS-11355; CG-4

IUPAC name NA

CAS name N-ethyl-6-(methylthio)-1,3,5-triazine-2,4-diamine

CAS registry number 4147-58-4

Chemical structure

Common name NA

Company experimental name GS-26831; CG-2

IUPAC name NA

CAS name 6-(methylthio)-1,3,5-triazine-2,4-diamine

CAS registry number 5397-01-3

N

N

N

NH

S NH
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Physicochemical Properties of Ametryn.

Parameter Value Reference

Melting point 84.5-86 C MRID 40877301; Ametryn PC 

RED Chapter pH 8-9 at 20 C (1% solution in water)

Density, bulk density, or 

specific gravity

0.373 g/mL at 20 C

Water solubility 0.020 g/100 mL at 20 C

Solvent solubility 56.9 g/100 mL in acetone

61.4 g/100/mL in methylene chloride

51.6 g/100 mL in methanol

46.0 g/100 mL in toluene

24.2 g/100 mL in n-octanol

1.4 g/100 mL in n-hexane

Vapor pressure 2.74 x 10-6 mm Hg at 25 C

Dissociation constant, pKa 4.02 at 20 C

Octanol/water partition 

coefficient

KOW = 423 (log P = 2.63)

UV/visible absorption spectrum λmax = 223 nm
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Attachment 2: Ametryn Acute, Subchronic, and Chronic Toxicity Profile

Acute Toxicity Profile – Ametryn.

Guideline Study Type MRID(s) Results Tox Cat

870.1100 Acute oral-rat 40995814 LD50 = 1356 (1164-1581) mg/kg (M)

LD50 = 1009 (829-1229) mg/kg (F) III

870.1200 Acute dermal-rabbit 40995815 LD50 >2020 mg/kg III

870.1300 Acute inhalation-rat 42470902 LC50 >5.03 mg/L IV

870.2400 Acute eye irritation-rabbit 40995817

No corneal involvement, mild 

conjunctiva irritation (redness, 

chemosis, and discharge) reversed by 

72 hours in washed eyes.

III

870.2500 Acute dermal irritation-rabbit 40995818 Essentially non-irritating. IV

870.2600 Skin sensitization - guinea pig 40995819 Not a sensitizer.

Subchronic, Chronic, and Other Toxicity Profile – Ametryn.

Guideline No./Study 

Type

MRID No. (year)/ 

Classification/Doses Results

870.3100

90-Day oral toxicity -

rat

Old study. Refer to chronic dosing. 

870.3150

90-Day oral toxicity -

dog

Old study. Refer to chronic dosing. 

870.3200

21-Day dermal 

toxicity - rabbit

41067902 (1989), 

Acceptable/Non-Guideline

0, 10, 100, or 1000 

mg/kg/day

NOAEL = 100 mg/kg/day.

LOAEL = 1000 mg/kg/day based primarily on body-weight gain 

effects and decreased food consumption. 

Note: Study is non-guideline because on 5/sex/dose group were 

used. 

870.3250

90-Day dermal 

toxicity (species)

No study. 

870.3465

90-Day inhalation 

toxicity (species)

No study.

870.3700a

Prenatal 

developmental in rats.

00153215 (1985)

Acceptable/Guideline

0, 5, 50, or 250 mg/kg/day

Maternal NOAEL = 5 mg/kg/day.

LOAEL = 50 mg/kg/day based on ptosis and salivation.

Developmental NOAEL and LOAEL >250 mg/kg/day. No effects 

at highest dose tested. 

870.3700b

Prenatal 

developmental in 

rabbits

00153214 (1985)

Acceptable/Guideline

0, 1, 10, or 60 mg/kg/day

Maternal NOAEL = 10 mg/kg/day.

LOAEL = 60 mg/kg/day based on body-weight loss, deceased feed 

consumption and increased liver weight. 

Developmental NOAEL and LOAEL >60 mg/kg/day. No effects 

at highest dose tested. 

870.3800

Reproduction and 

fertility effects

(species)

40349905 (1987)

Acceptable/Guideline

0, 1.3, 13, or 131 mg/kg/day 

in males (approximately). 

0, 1.2, 12, or 117 mg/kg/day 

in females (approximately). 

Parental/Systemic NOAEL = 13 mg/kg/day.

LOAEL = 131 mg/kg/day based on decreased body weight and 

weight-gain and decreased feed efficiency. 

Reproductive NOAEL and LOAEL >131 mg/kg/day. No effects 

at highest dose tested. 

Offspring NOAEL = 13 mg/kg/day.

LOAEL = 131 mg/kg/day based on decreased pup weights and 

weight gain in the F2 generation. 

870.4100a

Chronic toxicity

Refer to 870.4300 combined chronic feeding/carcinogenicity study in rats below. 

870.4100b

Chronic toxicity (dog)

40349902 (1987)

Acceptable/Guideline

0, 0.71, 7.2, 70, 103, and 83 

mg/kg/day in males and 0, 

0.84, 8.1, 74, 112, and 92 

mg/kg/day in females. 

NOAEL = 7.2 mg/kg/day.

LOAEL = 70 mg/kg/day based on degenerative liver lesions. 
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Subchronic, Chronic, and Other Toxicity Profile – Ametryn.

Guideline No./Study 

Type

MRID No. (year)/ 

Classification/Doses Results

870.4300

Carcinogenicity

(mouse)

40349904 (1981)

“CORE MINIMUM”

0, 1.5, 150, or 300 

mg/kg/day. 

NOAEL and LOAEL >300 mg/kg/day. No effects at highest dose 

tested. 

No evidence of carcinogenicity.

Note: Marked decreases in body weight at 3000 ppm justify 

selection of 2000 ppm (i.e. about 300 mg/kg/day) as an acceptable 

dose. 

870.4300. Chronic 

Feeding/

Carcinogenicity

(rat)

40349906 (1987), 41184201 

(1987) and 403

82001 (1987)

Acceptable/Guideline

0, 2, 21, or 145 mg/kg/day 

for males and 0, 2.5, 26, or 

176 mg/kg/day for females. 

NOAEL = 21 mg/kg/day.

LOAEL = 145 mg/kg/day based on based on decreased body 

weight and weight gain in both sexes and histopathological lesions 

in the kidney, testes, and pituitary in male rats and in the liver and 

pancreas in male and female rats.

Gene Mutation

870.5100. Ames test, 

bacterial mutation. 

40995829 and 41189701 

(1984) 

Acceptable/Guideline

0, 20, 80, 320, 1280, or 5120 

μg/mL.

No evidence of mutagenicity in Salmonella strains TA98, TA 100, 

TA 1535 and TA 1537 up to levels causing cytotoxicity. 

Cytogenetics 

870.5395. Mouse 

micronucleus test. 

41067903 (1989) 

Acceptable/Guideline

1. 800 mg/kg, harvest at 16, 

24, and 48 hours.

2. 200, 400, or 800 mg/kg: 

harvest at 24 hours.

Negative for increased MPCEs up to clinical toxicity (death). 

Other Effects 

870.5550. 

Unscheduled DNA 

synthesis in rat 

hepatocytes. 

41067904 (1989)

Acceptable/Guideline.

1. 0.1 to 100 μg/mL

2. 0.137 to 33.3 μg/mL 

Negative for increases UDS up to cytotoxicity. 

870.6200a

Acute neurotoxicity 

screening battery

No study. 

870.6200b

Subchronic 

neurotoxicity 

screening battery

No study.

870.6300

Developmental 

neurotoxicity

No study. 

870.7485

Metabolism and 

pharmacokinetics

(species)

41463301, 41463302, 

41463303 (all 1990)

Acceptable. 

Ametryn is readily absorbed by rats after a single or multiple oral 

doses of 0.5 or 200 mg/kg. It is widely distributed, being found in 

all tissues and organs tested although in low levels. It is 

metabolized to several polar products, 13 of which were identified. 

It is excreted mainly through the urine (50-61%) within 48 hours 

with the feces being the other major route (30-42%). No 

significant differences in pharmacokinetic parameters were seen 

among dosing groups (singular oral high and low, multiple low) or 

between sexes. 

870.7600

Dermal penetration

(species)

No study. 

Special studies No studies. 
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Attachment 3: Ametryn Endpoint Selection Tables.

Summary of Toxicological Doses and Endpoints for Ametryn Used in the 2005 RED.

Exposure

Scenario

Dose Used in Risk 

Assessment, UF

Special FQPA SF* 

and Level of Concern 

for Risk Assessment

Study and Toxicological Effects

Acute Dietary

(females 13-49) &

(general population)

No selection

Chronic Dietary

(all populations)

NOAEL = 7.2 

mg/kg/day

UF = 100

1X

cRfD = cPAD = 0.072 

mg/kg/day

Dog chronic feeding study with 

indications of degenerative and 

inflammatory liver effects at LOAEL 

of 70 mg/kg/day.

Incidental Oral 

Short-Term

(1 - 30 days) &

Intermediate-Term

(1 - 6 months)

NOAEL = 10 

mg/kg/day

MOE = 100

1X Rabbit developmental toxicity. Body 

weight and deceased feed 

consumption and increased liver 

weight at the LOAEL of 60 

mg/kg/day.

Dermal

Short-Term

(1 - 30 days) &

Intermediate-Term

(1 - 6 months)

NOAEL = 100 

mg/kg/day

MOE = 100

1X Rabbit 21-day dermal toxicity study. 

Body-weight gain decrease at 1000 

mg/kg/day.

Dermal

Long-Term

(> 6 months)

Same as for cRfD. MOE = 100. Dermal-absorption factor of 6% recommended.

Inhalation

Short-Term

(1 - 30 days) &

Intermediate-Term

(1 - 6 months)

Same as for incidental oral. MOE = 100. Assume 100% absorption following 

inhalation.

Inhalation

Long-Term

(> 6 months)

Same as for cRfD. MOE = 100. Assume 100% absorption following inhalation.

Cancer (oral, 

dermal, inhalation) No quantitative carcinogenicity risk assessment is required.

UF = uncertainty factor, FQPA SF = Special 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, MOE = margin of exposure, LOC = level of 

concern, NA = not applicable
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Attachment 4: Summary of Occupational Uses Based on Registered Label.

Evik®80WDG (EPA Reg. #100-786; 12-15-09)

Crop Application 

equipment

Applic. 

Rate (lb 

ai/A)

Max. No. 

Applic. per 

Season

Max. 

Seasonal 

Applic. Rate 

(lb ai/A)

PHI 

(days)

Use Directions and 

Limitations

Corn (field 

corn, popcorn) Groundboom 1.6 1 1.6 30

No aerial or chemigation 

applications. Apply as a 

postemergence directed 

spray to weeds after the 

smallest corn is at least 12 

inches high. Do not spray 

over top of corn. Do not 

apply within 3 weeks of 

tasseling.

Pineapple Groundboom 1.6 2 3.2 160

No aerial or chemigation 

applications. Use only in 

Hawaii. Apply 

immediately after planting 

or after previous crop 

harvest and before weeds 

emerge. 

Sugarcane

Aerial and 

Groundboom FL: 1.2 2 FL: 2.4

NS

Apply as broadcast spray 

or directed to the base of 

the plant. Avoid wetting 

sugarcane foliage. Make 

applications prior to closein1

. 

Groundboom LA, TX: 

1.2 2 LA, TX: 2.4

Apply broadcast or band 

over the top of the plant or 

as a directed spray. Do not 

apply over the top of plant 

after April 10, or after plant 

exceeds 20 inches in 

height. Make final 

application before close-in.

Groundboom HI: 2.4 3 HI: 7.2

Apply before weeds or 

sugarcane emerge. May 

apply up to 30 days prior to 

close-in or at close-in, if 

needed. 

1. Weed control is most critical early in the season prior to sugarcane canopy closure over the row middles.
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Attachment 5: Ametryn International Residue Limit Status Sheet.

Ametryn (080801); current as of 12/19/12

Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition:

US Canada Mexico1 Codex

40 CFR 180.258:

Plant: ametryn (2-ethylamino)-4-(isopropylamino)-6-

(methylthio)-s-triazine)

Livestock: NA

None None

Commodity Tolerance (ppm) /Maximum Residue Limit (mg/kg)

US Canada Mexico1 Codex

Banana 0.25

Corn, field, forage 0.1

Corn, field, grain 0.05

Corn, field, stover 0.05

Corn, pop, grain 0.05

Corn, pop, stover 0.05

Corn, sweet, forage 0.5

Corn, sweet, kernel plus cob with 

husk removed

0.25

Corn, sweet, stover 0.5

Pineapple 0.05

Sugarcane, cane 0.05

Completed: M. Negussie; 12/19/2012

1 Mexico adopts US tolerances and/or Codex MRLs for its export purposes.