Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL SAFETY AND 

 POLLUTION PREVENTION

MEMORANDUM

Date: 24-March-2011 

SUBJECT: Metconazole. Petition for Registration of Use on Tuberous and Corm Vegetables 

Subgroup 1C and Bushberry Subgroup 13-07B (PP#0E7743). Summary of 

Analytical Chemistry and Residue Data. 

PC Code: 125619 DP Barcode: D380990 

Decision No.: 436782 Registration No.: 59639-147 

Petition No.: 0E7743 Regulatory Action: Sec. 3 Registration 

Risk Assessment Type: N/A Case No.: N/A 

TXR No.: N/A CAS No.: 125116-23-6

MRID No.: See MRID Summary Table 40 CFR: §180.617

From: Amelia M. Acierto, Chemist 

 Risk Assessment Branch III 

 Health Effects Division (7509P) 

Through: Stephen Funk, Senior Chemist 

 Risk Assessment Branch III 

 Health Effects Division (7509P)

To: Barbara Madden RM 5 

 Risk Integration, Minor Use, & Emergency Response Branch 

 Registration Division (7505P) 

 

Note: This document was originally prepared under contract by Versar, Inc. (6850 Versar Center, Springfield, VA 22151; 

submitted 1/31/11). The DER has been reviewed by the Health Effects Division (HED) and revised to reflect current Office of 

Pesticide Programs (OPP) policies. 

MRID Summary Table 

MRID No. Study Type Comments 

48143301 860.1500 (potato field trials) 

860.1520 (potato processing study) 

New DER; 48143301.der1 (860.1500) 

New DER; 48143301.der2 (860.1520) 

48143302 860.1500 (blueberry field trials) New DER; 48143302.der (860.1500) 
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Executive Summary

The Interregional Research Project No. 4 (IR-4), on behalf of the Agricultural Experiment 

Stations of New York, New Jersey, Ohio, Maryland, Florida,Wisconsin, North Dakota,Texas, 

Colorado, California, Washington, and Idaho, has submitted potato field trials during the 2007 

growing season, and on behalf of the agricultural stations of New Jersey, North Carolina, 

Michigan, and Oregon, has submitted high bush blueberry crop field trials during the 2006 

growing season in the U.S., and New Brunswick, Nova Scotia and Quebec for low bush 

blueberry field trials in Canada. Concomitantly, IR-4 has submitted a petition (PP#0E7743) 

proposing the establishment of tolerances for the residues of the fungicide metconazole, 5-[(4-

chlorophenyl)methyl]-2,2-dimethyl-1-(1H-1,2,4-triazol-1-ylmethyl)cyclopentanol, in/on the 

following raw agricultural commodities (RAC): 

 

Tuberous and Corm Vegetable subgroup 1C ...........0.02 ppm 

Bushberry subgroup 13-07B ....................................0.35 ppm 

In conjunction with this petition, IR-4 is requesting an amended registration of a 50% water 

dispersible granule formulation of metconazole to allow use on tuberous and corm vegetables 

and bushberries. Potato and blueberry (high and low bush) were the representative crops used to 

generate data in support of the subject petition. 

The end-use product (EP) relevant to this petition is Metconazole 50 WDG or V-10116 50 WDG 

registered to Valent USA Corporation (EPA Reg. No. 59639-147). Under the proposed use, four 

foliar applications will be made to potato at 0.078-0.125 lb ai/A/application for a total seasonal 

rate of 0.500 lb ai/A and three applications will be made to blueberry at 0.078 lb ai/A/application 

for a total seasonal rate of 0.234 lb ai/A. For potato, the preharvest interval (PHI) is 1-2 days; at 

two test sites (ID10 and ND10) additional samples were harvested at 3, 7, and 14 days for the 

residue decline study and at two test sites (WA33 and TX28) samples from added plots treated 

at the exaggerated rate of ≥5x were harvested at 1 day PHI for processing potato commodities. 

For blueberry, the PHI is 7 days and at 2 test sites (MI32 and NS01) additional samples were 

harvested at 0, 1, 3, and 10 days for residue decline determinations. 

Tolerances for residues of metconazole are established under 40 CFR §180.617 and are 

expressed in terms of the fungicide metconazole or in terms of the fungicide metconazole, 

including its metabolites and degradates determined by measuring only metconazole as the sum 

of its cis- and trans- isomers [40 CFR §180.617(a)(1) and (2). Permanent tolerances have been 

established for a variety of raw agricultural and processed commodities including tree nuts, 

banana, barley, sugar beet, stone fruits, cereal grains, peanuts, soybean, canola, corn, and cotton 

commodities at tolerance levels ranging from 0.01-18 ppm. Tolerances for meat byproducts of 

cattle, goat, horse, and sheep, and egg are established at 0.04 ppm. Section 18 time-limited 

tolerances are established under §180.617(b) for sugarcane cane and molasses at 1.6 and 3.2 

ppm, respectively, and are set to expire on 12/31/11. 
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An adequate gas chromatography method with nitrogen-phosphorus-detection (GC/NPD) is 

available for data collection and enforcement of tolerances for residues of metconazole parent 

isomers (cis- and trans- metconazole) in plant commodities based on Valent Method RM-41C-1, 

“Determination of cis and trans–Metconazole in Crops.” An adequate high performance liquid 

chromatography (HPLC) method is available for data collection and enforcement of tolerances 

for residues of 1,2,4-triazole (T), triazole alanine (TA), and triazole acetic acid (TAA). The 

method is based on Morse Laboratories, Inc. analytical method, Meth-160, Rev. 2, 

“Determination of 1,2,4-Triazole, Triazole Alanine and Triazole Acetic Acid Residues in Plants 

and Animal Matrices.” The GC/NPD and HPLC methods were adequately validated prior to and 

concurrently with the analyses of the crop field samples. The lowest level of method validation 

(LLMV) in potato was 0.02 ppm for both metconazole and the triazole metabolites, and in 

blueberry, the LLMV is 0.05 ppm for metconazole and 0.02 ppm for the triazole metabolites. 

For metconazole residues in potatoes, the calculated limits of detection (LOD) are 0.0037 and 

0.0056 ppm for cis and trans-metconazole, respectively. For the triazole metabolites, the 

calculated LODs are 0.0052, 0.0066 and 0.0078 ppm for T, TA, and TAA, respectively. For 

metconazole residues in blueberries, the calculated LODs are 0.0012 and 0.0092 ppm for cis and 

trans-metconazole, respectively. For T, TA, and TAA in blueberries based on the recoveries of 

samples fortified at 0.02 ppm, the calculated LODs are 0.010, 0.0042 and 0.011 ppm, 

respectively. 

The LOQ is defined as the lowest fortification level of an analyte at which acceptable recovery 

data can be achieved. The LOQ is equivalent to the lowest level method validated (LLMV). 

Additional multiresidue method testing data required from a previous petition remain 

outstanding for metconazole. It was concluded (DP# 361110) that further work is required to 

test the separation of metconazole on OV-17 and OV-225 columns under Protocol C. 

No new metabolism studies were submitted. The nature of metconazole residues in plants and 

animals is understood based on adequate metabolism studies on banana, canola, mandarin 

oranges, pea, wheat, goats, and hens. For the tolerance expression, HED has determined that the 

residue of concern in plant and livestock commodities is metconazole (parent). For purposes of 

risk assessment, HED has concluded that the residues of concern in primary crops, except cereal 

grains, are metconazole (parent). For cereal grains, residues of metconazole and Metabolite M11 

will be used for risk assessment. For livestock commodities, the residues of concern for risk 

assessment include metconazole and Metabolites M1 (free and conjugated), M12, and M31 (free 

and conjugated). 

In the potato crop field trial study, residues of the parent metconazole, T, and TAA were not 

detected above the LOQ. Residues of TA were 0.023–0.037 ppm (corrected values based on the 

control). Similarly, in blueberry, only the TA was detected over 14 days in the residue decline 

study with corrected residues <0.02 ppm. 

The submitted field trials for potato and blueberry are supported by acceptable storage stability 

data for metconazole isomers (cis- and trans-metconazole). Available data demonstrate that 

metconazole parent is relatively stable for up to 12 months in various crop matrices; T and TAA 

were found stable for up to 6 months and TA was stable for up to 12 months. The current 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

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storage stability study shows that metconazole isomers (cis- and trans-metconazole) were stable 

for at least 281 days (9.2 months) in blueberry fruits and 959 days (31.5 months) in potato tubers. 

Although the samples for determination of triazole metabolites were stored for 875 days (28.8 

months) for blueberry and 622 days (20.4 months) for potato, stability data were not submitted. 

The submitted potato processing study indicate that residues of metconazole were <LOQ in/on 

potato RAC samples following application of the 50% WDG formulation at the exaggerated 

rates of 5x or 6.2x the maximum proposed seasonal rate. Based on this result, HED concludes 

that quantifiable residues of metconazole are not expected in the potato processed commodities 

(potato flakes/granules, potato chips and wet peels) and tolerances are not needed for the potato 

processed commodities. 

The ruminant feedstuffs associated with the proposed use of metconazole are processed potato 

waste and cull potatoes. However, the use of metconazole in/on tuberous and corm vegetables is 

not expected to alter the dietary exposure of ruminants based on very low (<LOQ) residues in the 

potato RAC samples treated at the ≥5x exaggerated rate. Therefore, no changes are required in 

the current livestock tolerances for metconazole. 

Adequate field trial data were submitted on the crop group/subgroup representative commodities 

to support the proposed uses of metconazole on tuberous and corm vegetables and bushberries. 

Based on the NAFTA tolerance spreadsheet as specified by the Guidance for Setting Pesticide 

Tolerances, the proposed tolerances on blueberries is too low. The data will support a tolerance 

of 0.40 ppm for bushberries. The tolerance spreadsheet was not used to calculate the tolerance 

for the tuberous and corm vegetables since the residues in potato were <LOQ. The tolerance 

should be established at 0.04 ppm, reflecting the combined LOQs of the metconazole 

enforcement method of 0.02 ppm for each metconazole isomer (cis- and trans-metconazole). 

There are no established or proposed Codex or Canadian maximum residue limits (MRLs) for 

metconazole in or on any food or feed crops; therefore, there are no harmonization issues. 

Regulatory Recommendations and Residue Chemistry Deficiencies

HED has examined the residue chemistry database for metconazole. Pending submission of a 

revised Section B (see requirements under Direction for Use) and Section F (see requirements 

under Proposed Tolerances), there are no residue chemistry issues that would preclude granting 

conditional registration and the establishment of a tolerance for the foliar uses of Metconazole 50 

WDG Fungicide (EPA Reg. No. 59639-147) in/on vegetable, tuberous and corm and bushberry. 

The registration is conditional pending resolution of the issues listed under “Deficiences” below 

Provided the forthcoming human health risk assessment does not identify any risks of concern, 

HED recommends for the establishment of the following tolerances: 

Vegetable, tuberous and corm, subgroup 1C ...........0.04 ppm 

Bushberry subgroup 13-07B ....................................0.40 ppm 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

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The remaining deficiencies regarding multiresidue methods (see 860.1360 below) and storage 

stability (see 860.1380 below) must be resolved as conditions of registration. 

A human health risk assessment, including examination of potential residues of 1,2,4-triazole, 

tiazole alanine, and triazole acetic acid in/on crops and livestock commodities is forthcoming. 

Note to PM:

The tolerance expression for metconazole in 40 CFR §180.617(a)(1) should be stated according 

to HED’s Interim Guidance on Tolerance Expression (5/27/09, S. Knizer) as follows: 

Tolerances are established for residues of metconazole, 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 metconazole [5-[(4-chlorophenyl)methyl]-2,2-

dimethyl-1-(1H-1,2,4-triazol-1-ylmethyl)cyclopentanol] as the sum of its cis- and trans-isomers. 

Deficiencies:

860.1200 Directions for Use

Since no spray adjuvants were used in the residue field trials on potatoes and blueberries, the 

label must be amended to include a statement that no adjuvant should be used for the tuberous 

and corm vegetable subgroup 1C and the bushberry subgroup 13-07B. 

 860.1360 Multiresidue Methods

HED has previously identified the need for metconazole to be tested through OV-17 and OV-225 

GC columns. This deficiency remains outstanding. 

860.1380 Storage Stability

Storage stability data for residues of 1,2,4-triazole, triazole acetic acid, and triazole alanine have 

not been submitted in conjunction with the subject petition . Although storage stability data for 

the triazoles are under review by the Agency, more data may be required to support this petition. 

860.1550 Proposed Tolerances

Section F should be revised to reflect the correct identification of the chemical being proposed. 

Propiconazole appears in Section F as the pesticide proposed. 

The commodity definition for tuberous and corm vegetables must be changed to Vegetable, 

tuberous and corm, subgroup 1C as shown in Table 8. 

A revised Section F should be submitted to propose a tolerance of 0.04 ppm for Vegetable, 

tuberous and corm, subgroup 1C and 0.40 ppm for bushberry subgroup 13-07 B. See Table 8. 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

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Background 

Metconazole [5-[(4-chlorophenyl)methyl]-2,2-dimethyl-1-(1H-1,2,4-triazol-1-

ylmethyl)cyclopentanol] is a broad-spectrum triazole fungicide (sterol biosynthesis inhibitor) and 

acts primarily as an inhibitor of fungal ergosterol biosynthesis, thereby interfering with synthesis 

of the fungal cell membrane.

The chemical structure and nomenclature of metconazole are summarized in Table 1, and the 

physicochemical properties of metconazole are summarized in Table 2. 

Table 1. Metconazole Nomenclature.

Chemical structure 

N

N

N

H3C

H3C

HO

Cl

cis-isomer 

N

N

N

H3C

H3C

HO

Cl

trans-isomer 

Common name Metconazole 

Company experimental name V-10116 

IUPAC name (1RS,5RS:1RS,5SR)-5-(4-chlorobenzyl)-2,2-dimethyl-1-(1H-1,2,4-triazol-1-

ylmethyl)cyclopentanol 

CAS name 5-[(4-chlorophenyl)methyl]-2,2-dimethyl-1-(1H-1,2,4-triazol-1-

ylmethyl)cyclopentanol 

CAS registry number 125116-23-6 (cis- and trans-isomers) 

115850-27-6 (cis-isomer) 

115850-28-7 (trans-isomer) 

End-use products (EP) 50% WG (Metconazole 50 WDG Fungicide, EPA Reg. No. 59639-147) 

Table 2. Physicochemical Properties of the Technical Grade Test Compound Metconazole.

Parameter Value Reference1

Melting point/range 100.0-108.4o

C (using Electrothermal Digital Melting Point 

Apparatus) (AC900,768 technical grade) 

44721505 

pH No data were submitted. 

Relative density at 20oC 

1.14 (relative density to water at 4o

C, using capillarystoppered, density-specific gravity bottle) (Lot No. AC 

8879-140B) 

44721505 

Water solubility (20 °C) Using shake flask method: 

18.7±1.0 mg/L (cis-isomer, WL148271, KNF-S-474m) 

13.6±1.7 mg/L (trans-isomer, WL148271, KNF-S-474m) 

44721505 
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Table 2. Physicochemical Properties of the Technical Grade Test Compound Metconazole.

Parameter Value Reference1

Solvent solubility (g/L at 20 °C) hexane: 1.40 

toluene: 103 

2-propanol: 132 

ethyl acetate: 260 

dichloromethane:481 

methanol: 403 

acetone: 363 

44721505 

Vapor pressure at 20 °C 

Using gas-saturation method at 20°C: 

< 1.23x10-5 Pa or 9.23 x 10-8 mm Hg (AC 900,768) 

< 1.04x10-5 Pa or 7.80 x 10-8 mm Hg (cis-isomer, CL 

354,801) 

< 1.96x10-6 Pa or 1.47 x 10-8 mm Hg (trans-isomer, CL 

354,802) 

44721505 

Dissociation constant (pKa) 11.38±0.03 and 1.06±0.03 (in water using 

spectrophotometric method) (Lot No. AC 8879-140B) 

44721505 

Octanol/water partition coefficient 

Log(Kow) 

Kow (log Kow) = 7090±989 (3.85) (using flask shaking 

method) (Lot No. AC 8879-140B) (TGAI) 

 Kow (log Kow) = 7150±803 (3.85) (using flask shaking 

method) (cis-isomer, CL 354,801) 

 Kow (log Kow) = 6800±1700 (3.8) (using flask shaking 

method) (trans-isomer, CL 354,802) 

44721505 

UV/visible absorption spectrum Not required for TGAI; required for pure active ingredient 

1

D256877, Shyam Mathur, 9/12/00 

860.1200 Directions for Use

IR-4 has submitted use directions under Section B of the petition which include the draft labeling 

for the 50 % WDG formulation of metconazole (V-10116 50 WDG, EPA Reg. No. 59639-147). 

A summary of the proposed use directions for the intended crops is presented in Table 3. 
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Table 3. Summary of Directions for Use of Metconazole. 

Applic. Timing, 

Type, and Equip.1 

Formulation 

[EPA Reg. 

No.] 

Applic.Rate 

oz/A 

(lb ai/A) 

Max. No. 

Applic. per 

Season

Max. 

Seasonal 

Applic. Rate 

(lb ai/A) 

PHI 

(days)

Use Directions and 

Limitations

Tuberous and Corm Vegetables (Subgroup 1C): arracacha; arrowroot; artichoke, Chinese; artichoke, 

Jerusalem; canna (edible); cassava (bitter and sweet); chayote (root); chufa; dasheen (taro); ginger; leren; 

potato; sweet potato; tanier; turmeric; yam bean; yam true 

Foliar, 

Broadcast, 

Ground (min. 10 

GPA2

) or aerial 

(min. 5 GPA) 

50% WG 

[59639-147] 

2.5 - 4.04

(0.078-

0.125) 

4 

(Maximum 

of 2 

sequential 

applications) 

16 

(0.500) 1

Use as part of an 

Integrated Pest 

Management (IPM) 

program3

. 

Apply when conditions 

favor disease 

development, prior to 

infection. Continue 

applications on a 7 to 14-

day retreatment interval. 

Do not apply more than 4 

applications per season. 

Do not make more than 2 

sequential applications. 

Do not apply more than 

16 oz/A (0.500 lb ai/A) 

/season. 

Bushberries (Subgroup 13-07B): aronia berry; blueberry, highbush; blueberry, lowbush; buffalo currant; 

Chilean guava; cranberry, highbush; currant, black; currant, red; elderberry; European barberry; 

gooseberry; honeysuckle (edible); huckleberry; jostaberry; juneberry (Saskatoon berry); lingonberry; 

native currant; salal; sea buckthorn; cultivars, varieties and/or hybrids of these. 

Foliar, 

Broadcast, 

Ground (min. 20 

GPA) or aerial 

(min. 10 GPA) 

50% WG 

[59639-147] 

2.5 

(0.078) 

3 

(Maximum 

of 2 

sequential 

applications) 

0.234 7 

Apply when conditions 

favor disease 

development, prior to 

infection, in sufficient 

water to obtain thorough 

coverage of blossoms, 

foliage, and/or fruit. 

Continue applications on 

a 7 to 14-day retreatment 

interval. Do not apply 

more than 3 applications 

per season. 1

 Do not apply through any type of irrigation system. 

2

 Gallons per acre. 

3

 Apply in a regularly scheduled spray program in combination and/or rotation with other effective fungicides that 

have different modes of action (i.e., non Group 3 fungicides). Avoid rotating with other sterol biosynthesis 

inhibitors, such as Folicur®, Nova®, Procure® or Tilt®. 4

 For the control of white mold (Sclerotinia sclerotiorum), use 4 oz /A (0.125 lb ai/A) per application. Make first 

application prior to infection, generally at row closure and/or first bloom and the second application 14 days later 

if conditions favor white mold development. 

 

Conclusions. The submitted use directions are sufficient to allow for evaluation of the available 

residue data relative to the proposed uses. The submitted field trial data reflect the proposed 

directions for potato and blueberry. 
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Since no spray adjuvants were used in the residue field trials on potatoes and bushberries, the 

“Crop Specific Directions/Restrictions and Limitations” on the 50% WDG label for Bushberry, 

Subgroup 13-07 B and for Vegetable, Tuberous and Corm ,Subgroup 1C must state that no spray 

adjuvant should be used for these crops. 

860.1300 Nature of the Residue - Plants

DP#s 361110 and 361111, 2/26/10, D. Soderberg (PP#6F7094) 

DP# 348234, C. Olinger, 2/11/08 (ROCKS memo) 

DP#s 348168 and 348206, 2/20/08, N. Dodd (PP#6F7094 and PP#6F7095) 

DP# 324541, 12/14/05, N. Dodd (PP#9E5052) 

No new metabolism data were submitted with the subject petition. Metabolism studies with 

banana, canola, mandarin, pea, and wheat were previously submitted. The metabolism of 

metconazole was found to be similar in all crops investigated. The main metabolic route of 

metconazole in crops is via oxidative hydroxylation of the methylene groups, the methyl groups 

on the cyclopentyl ring, and possibly the cyclopentyl ring. In addition, monohydroxylation may 

occur at the various pro-chiral carbons of metconazole, giving rise to chromatographically 

distinguishable stereoisomeric structures. The detection of TA and triazole conjugates in the 

canola, pea, and wheat studies indicates that the methylene group between the triazole and 

cyclopentyl rings is susceptible to oxidative hydroxylation. HED has determined that 

metconazole (parent) is the residue of concern for both the tolerance expression and risk 

assessment purposes in plants except for cereal grains; the residues of concern for risk 

assessment in small grains are metconazole and the metabolite M11. 

Conclusion: For the purpose of the subject petition, the nature of the residue in plants is 

adequately understood. 

860.1300 Nature of the Residue - Livestock

DP# 348234, C. Olinger, 2/11/08 (ROCKS memo) 

DP# 348168, 2/20/08, N. Dodd (PP#6F7094 and PP#6F7095) 

No new metabolism data were submitted with the subject petition. Adequate ruminant and 

poultry metabolism studies are available, and the data indicate that the metabolism of 

metconazole in ruminants and poultry is generally similar. The major routes of metabolism 

involve oxidation and/or oxidative hydroxylation of the methyl group at position 2 of the 

cyclopentyl ring and oxidative hydroxylation of the phenyl ring. Glucuronic acid conjugates 

were observed in the goat metabolism studies, and sulfate ester conjugates were observed in the 

hen metabolism study. In addition, in the hen metabolism study with triazole-labeled 

metconazole, C-N bond cleavage releasing 1,2,4-T was observed. Based on the available data, 

HED has determined that the residue of concern for the tolerance expression in livestock 

commodities is metconazole (parent). The residues of concern in livestock for purposes of the 

risk assessment are metconazole and Metabolites M1 (free and conjugated), M12, and M31 (free 

and conjugated). 
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860.1340 Residue Analytical Methods

An adequate gas chromatographic method with a nitrogen-phosphorous detection (GC/NPD) for 

determining residues of metconazole parent isomers (cis- and trans-metconazole) and a high 

performance liquid chromatographic (HPLC) method for determining residues of the triazole 

metabolites (1,2,4-triazole, triazole acetic acid, and triazole alanine) are available for 

enforcement and data collection in plant commodities. The GC/NPD method has been reviewed 

by ACB/BEAD and found to be adequate for enforcing tolerances of metconazole (parent) in/on 

peanuts, stone fruit, and tree nuts (DP# 339995, Paul Golden, 2/15/08). The GC/NPD method is 

based on Valent Method RM-41C-1, “Determination of cis- and trans-Metconazole in Crops 

utilizing a gas chromatograph with a nitrogen-phosphorous detector (GC/NPD)”. The HPLC 

method is based on the Morse Analytical Method #160, “Determination of 1,2,4-Triazole, 

Triazole Alanine and Triazole Acetic Acid Residues in Plant and Animal Matrices.” 

Metconazole. Briefly, 10 g. ground samples are extracted for residues of metconazole parent 

isomer (cis- and trans-metconazole) with acetonitrile:water (70:30, v/v), homogenized for 15 

minutes and vacuum filtered through 2 layers of Whatman No. 1 in a Buchner funnel to remove 

solids. Transfer extract into a round bottom flask and remove the acetonirile by rotary 

evaporation in a water bath (<35o

C) to obtain an aqueous residue. Transfer the residues to a 

separatory funnel. Rinse the round bottom flask 3 times with hexane and add washings to the 

aqueous residues in the separatory funnel. Drain the aqueous (lower) phase back to the round 

bottom flask and the hexane layer into a clean separatory funnel. Add 150 mL acetonitrile to the 

hexane extract in the separatory funnel. Shake funnel to allow the phases to separate. Drain the 

acetonitrile layer into a clean boiling flask. Add 100 mL acetonitrile to the separatory funnel 

with the hexane. Repeat partition. Drain the acetonitrile layer into the round bottom flask and 

evaporate just to dryness by rotary evaporation in a heated water bath. Add 5 mL 

methanol:water (1:1, v/v) to the flask, sonicate briefly to dissolve the residues and transfer to a 

preconditioned C18 solid phase extraction (SPE) cartridge. Rinse the flask twice with 5 mL 

methanol:water (1:1, v/v), each time adding to the C18 SPE cartridge, 

Elute the cis and trans-metconazole residues into a 100 mL boiling flask by rinsing the 500 mL 

flask with 2 x 5 mL methanol:water (5:1) and transferring to the C18 SPE cartridge, Add 30 mL 

ethyl acetate to the 100 mL flask and rotary evaporate using a heated water bath. Add 60 mL to 

the aqueous residue to azeotrope the water. Continue to rotary evaporate just to dryness. 

(Additional ethyl acetate may be required to remove the water). Add toluene, stopper and 

sonicate briefly to dissolve the residues. Bring to final volume (typically 2.0 mL for control 

samples and 10 mL for the samples fortified at 0.05 ppm). Transfer aliquots to a GC vial for 

analysis by GC/NPD. 

The limit of quantitation (LOQ) in blueberry, based on lowest level of method validation 

(LLMV) was 0.05 ppm for each metconazole isomer (cis- and trans-metconazole); 

corresponding limits of detection (LODs) were 0.012 and 0.0092 ppm. In potato, the LOQ based 

on the LLMV was 0.02 ppm for each metconazole isomer (cis- and trans-metconazole); 

corresponding limits of detection (LODs) were 0.0037 and 0.0056 ppm. 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

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Triazole metabolites. Briefly, 5.0 g macerated samples are extracted for residues of triazole 

metabolites with 60 mL methanol:DI water (80:20, v/v. Add 1 gram Celite® to the crude 

sample, mix thoroughly and vacuum filter through Whatman GF/A filter in Buchner funnel into 

a 125 mL filter flask. Rinse the extraction jar and filter cake with about 5 mL methanol:DI water 

(80:20, v/v) into the filter flask. This is repeated twice. Re-rinse filter cake with 5 mL 

methanol:DI water (80:20, v/v). Transfer extracts to a 100 mL graduated mixing cylinder and 

bring to volume (100 mL) with methanol:DI water (80:20, v/v). Process three 1 mL aliquots of 

extracts separately for each of the three metabolites through the clean-up and derivitization steps. 

The 1,2,4-triazole aliquot is directly derivatized with dansyl chloride and partitioned into ethyl 

acetate. The triazole alanine aliquot is purified through Bond Elut SPE cartridge and then 

subjected to two derivatizations by esterification using HCl/butanol followed by acylation using 

heptafluorobutyric anhydride. The triazole acetic acid aliquot is purified through a C18 SPE 

cartridge and then derivatized using HCl/butanol esterification. All the three derivatized extracts 

are separately evaporated to dryness, redissolved in acetonitrile:water (30:70, v/v), and analyzed 

using high performance liquid chromatography. 

The limit of quantitation (LOQ) in blueberry, based on the lowest level of method validation 

(LLMV) was 0.02 ppm for each triazole metabolite (1,2,4-triazole, triazole alanine and triazole 

acetic acid); corresponding limits of detection (LOD) were 0.010, 0.0042, and 0.011 ppm. In 

potato, the LOQ based on the LLMV was 0.02 ppm for each triazole metabolite (1,2,4-triazole, 

triazole alanine and triazole acetic acid); corresponding LODs were 0.0052, 0.0066 and 0.0078 

ppm. 

The methods for the determination of metconazole and triazole metabolites were validated prior 

to and in conjunction with the analysis of field trial samples. Control samples of blueberry were 

fortified at 0.05, 0.20, and 2.0 ppm or 0.020 and 0.2 ppm for concurrent recoveries of 

metconazole (cis-metconazole and trans-metconazole) and triazole metabolites (1,2,4-triazole, 

triazole alanine, and triazole acetic acid), respectively. In addition, control samples of blueberry 

were fortified at 0.020, 0.04, 0.05, 0.20 and 2.0 ppm or 0.020, 0.20, and 2.0 ppm prior to analysis 

for method validation of metconazole (cis-metconazole and trans-metconazole) and triazole 

metabolites (1,2,4-triazole, triazole alanine, and triazole acetic acid), respectively. 

Conclusions. The residue analytical methods are adequate for data collection based on 

acceptable method validation and concurrent method recoveries. The GC/NPD method has been 

reviewed by ACB/BEAD and found to be adequate as an enforcement method for metconazole. 

860.1360 Multiresidue Methods

DP#s 361110 and 361111, 2/26/10, D. Soderberg (PP#6F7094) 

DP# 324541, 12/14/05, N. Dodd (PP#9E5052) 

The Agency previously reviewed multiresidue methods data for metconazole. Based on its 

chemical structure, metconazole was not tested using FDA Multiresidue Method Protocols A, B, 

and G. In Protocol C testing, an acceptable GC response was obtained under Level I conditions 

using Module DG5, although the test was not conducted in accordance with Protocol C; testing 

was not conducted on an OV-17 or OV-225 column as required in Protocol C. Subsequent 

testing through Protocols D and E indicated that metconazole was poorly recovered through 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 12 of 27

Florisil cleanup, and was not determined by electron capture detection (ECD) with or without 

cleanup. Based the results of testing under Protocols D and E, metconazole was not tested 

through Protocol F. 

Conclusions: Under DP#s 361110 and 361111, it was concluded that further work is required to 

test the separation of metconazole on OV-17 and OV-225 columns under Protocol C; no further 

work on other protocols is needed. This deficiency remains outstanding. 

860.1380 Storage Stability

Potato RAC samples from each of the crop field trials were stored frozen at <-20o

C prior to 

extraction and analysis for up to 126 days (4.1 months) for metconazole and up to 622 days (20.4 

months for triazole metabolites. Blueberry RAC samples were stored frozen at <-20 oC up to 281 

days (9.2 months) for metconazole and 875 days (29 months) for triazole metabolites. The 

maximum storage intervals of samples from the crop field trial associated with this petition are 

presented in Table 4. Concurrent storage stability studies were conducted for metconazole to 

support the sample storage durations and conditions of the submitted crop field trials. Untreated 

RAC samples were fortified with cis- and trans-metconazole at 2.0 ppm for each analyte in 

potato in blueberry. Samples were stored at <-20°C for 959 days for potato and for 281 days for 

blueberry, and were analyzed concurrently with freshly fortified samples. The results show that 

residues of metconazole are stable in frozen potato and blueberry for up to 959 and 281 days, 

respectively. No 0-day data were provided. 

Although samples for triazole metabolites determination were stored for 875 days (29 months) 

in blueberry and 622 days (20.4 months) in potato, the stability under frozen conditions were not 

determined. HED has concern for residues of free 1,2,4-triazole (T) and its conjugates, triazole 

alanine (TA) and triazole acetic acid (TAA), in plants and animals as a result of the use of 

metconazole. Storage stability data were not submitted with this petition. However, data on the 

storage stability of triazoles were received by the Agency and are currently under review. 

The storage durations and conditions of samples from the crop field trials and processing studies 

submitted to support this petition are presented in Table 4. 

Table 4. Summary of Storage Conditions and Durations of Samples from Crop Field Trial and Processing 

Studies. 

Matrix Analyte Storage 

Temperature (°C) 

Actual Storage 

Duration 

Interval of Demonstrated 

Storage Stability 

Potato RAC 

(field trial (1x) 

Metconazole 

(cis- and transmetconazole) 

<-20 28-126 days 

(1-4.1 months) 

959 days 

(31.5 months) 

Triazole metabolites 

(1,2,4-Triazole, 

Triazole alanine, 

Triazole acetic acid) 

426-622 days 

(14-20.4 months) 

No data available 

Potato RAC 

Processing 

study/(5x) 

Metconazole 

(cis- and transmetconazole) 

<-20 126 days 

(4.1 months) 

959 days 

(31.5 months) 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 13 of 27

Table 4. Summary of Storage Conditions and Durations of Samples from Crop Field Trial and Processing 

Studies. 

Matrix Analyte Storage 

Temperature (°C) 

Actual Storage 

Duration 

Interval of Demonstrated 

Storage Stability 

Triazole metabolites 

(1,2,4-Triazole, 

Triazole alanine, 

Triazole acetic acid) 

622 days 

(20.7 months) 

No data available 

Blueberry Metconazole 

(cis- and transmetconazole) 

<-20 231-281 days 

(7.6-9.4 months) 

281 days 

Triazole metabolites 

(1,2,4-Triazole, 

Triazole alanine, 

Triazole acetic acid) 

812-875 days 

(27-29 months) 

No data available 

Conclusions. The submitted storage stability data for metconazole are adequate to support the 

subject crop field trials. Storage stability data for the processed commodities were not 

determined since metconazole residues in the ≥5x-treated RAC samples were <LOQ. 

Interim storage stability data for T, TA, and TAA in canola seed, turnip roots, mustard greens, 

wheat straw, grain, and forage were referenced in connection with a prothioconazole petition 

(PP#4F6830; DP#s 303508 & 314517, S. Funk, 8/21/2006). Interim storage stability data 

referenced in connection with a triticonazole petition (PP#8F7420, DP#s 325956, 353372, and 

360624, A. Acierto, 6/12/2009) suggest that residues of T, TA and TAA are reasonably stable 

when stored frozen for up to one year in/on apples and wheat flour. (Study on peanut butter was 

to be repeated). 

860.1400 Water, Fish, and Irrigated Crops

There are no proposed uses that are relevant to this guideline topic. 

860.1460 Food Handling

There are no proposed uses that are relevant to this guideline topic. 

860.1480 Meat, Milk, Poultry, and Eggs

DP#s 350367 and 353357, 9/18/08, N. Dodd (PP#7F7292) 

No livestock feed items are associated with bushberries. The only livestock feedstuffs associated 

with PP#0E7743 are processed potato waste and potato culls; these commodities are fed to beef 

and dairy cattle but are not fed to poultry or swine. The dietary burdens of metconazole to 

livestock, based on reasonably balanced diets, were calculated in DP# 350367. Dietary burdens 

were 4.2 and 6.6 ppm for beef and dairy cattle, respectively, and 1.9 and 0.64 ppm for poultry 

and swine, respectively, and were calculated based on tolerances for cereal grain, sugarcane, 

cotton, and soybean commodities. 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 14 of 27

Residues of metconazole from the submitted crop field studies were below the LOQ in/on 

potatoes following application at 5x the proposed maximum seasonal application rate; therefore, 

quantifiable residues of metconazole are not expected in potato processed commodities. 

Conclusions. The addition of the use of metconazole on tuberous and corm vegetables is not 

expected to alter the dietary exposure of ruminants because residues of metconazole were 

nonquantifiable in potato treated at 1x and 5x the maximum proposed seasonal application rate. 

Therefore, no changes are required in the current livestock tolerances for metconazole. 

860.1500 Crop Field Trials 

:

48143301.der1 (potato) 

48143302.der (blueberry) 

Potato 

The IR-4, on behalf of the Agricultural Stations of Idaho, Michigan, North Dakota, North 

Carolina, and Oregon has submitted field trial data for metconazole on potatoes. Seventeen 

potato field trials were conducted during the 2007 growing season in NAFTA Zones 1 (NY and 

OH; 3 trials), 2 (NJ and MD; 2 trials), 3 (FL; 1 trial), 5 (WI and ND; 2 trials), 6 (TX; 1 trial), 8 

(CO; 1 trial), 10 (CA; 1 trial), and 11 (WA and ID; 6 trials). At each test location, there was one 

untreated and one treated plot. The treated plots received four foliar broadcast applications of 

Metconazole 50 WDG Fungicide (V-10116 50WDG), a water dispersible granule formulation 

containing 50% of metconazole [mixture of cis- and trans-metconazole (85:15 ratio)] as the 

active ingredient. Applications were made at a target rate of 0.125 lb ai/A per application in a 

spray volume of 16 - 29 gal/A. The total seasonal application rate was 0.50 lb ai/A. Retreatment intervals ranged from 6 to 8 days. No adjuvant was added to the spray mixtures in any 

of the crop field trials. 

Single untreated control and duplicate treated potato tuber samples were collected at pre-harvest 

intervals (PHIs) of 1-2 days. In addition, at two of the test sites (ID10 and ND10), one control 

and duplicate treated potato tuber samples were also collected at 3 or 4, 7 or 8, and 14 or 15 days 

after the last application to determine residue decline. 

Following four foliar broadcast applications of metconazole at a total rate of 0.496-0.529 lb ai/A, 

total metconazole residues (cis-metconazole and trans-metconazole) in/on potatoes harvested at 

1- to 2-day PHIs were below the LOQ (<0.04 ppm). Based on these low residues, the tolerance 

spreadsheet for estimating tolerances was not utilized. 

At two test sites (ID10 and ND10), additional samples were harvested at 3 or 4, 7 or 8, and 14 or 

15 days for residue decline studies. Residue decline for metconazole, could not be determined 

since the residues from PHI 0 to 15 days were all <LOQ (<0.02 ppm for each of cis- and transmetconazole). Residues of 1,2,4-triazole and triazole acetic acid in potato tubers were each 

<0.02 ppm; triazole alanine were observed in one (ND10) of the two sites for the residue decline 

studies although a clear pattern of decline is not clear. The average (uncorrected) residues of TA 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 15 of 27

were 0,022, 0.026, 0.027 and 0.026 ppm at PHI 1, 3, 7, and 14 days, respectively. Residue in the 

corresponding control was reported as 0.013 ppm. 

The results of the potato field trials are summarized in Table 5. 

Table 5. Summary of Residue Data from Potato Field Trials with a Metconazole Formulation (WDG).

Commodity Total 

Applic. Rate 

(lb ai/A) 

End-use 

Product

PHI2

(days)

Residue Levels (ppm)1 

n Min. Max. HAFT2 Mean Std. Dev. 

cis-Metconazole 

Tuber 0.496-0.529 V-10116 

50 WDG 1-2 34 <0.020 <0.020 <0.020 <0.020 NA 

trans-Metconazole 

Tuber 0.496-0.529 V-10116 

50 WDG 1-2 34 <0.020 <0.020 <0.020 <0.020 NA 

1,2,4-Triazole 

Tuber 0.496-0.529 V-10116 

50 WDG 1-2 34 <0.020 <0.020 <0.020 <0.020 NA 

Triazole Acetic Acid 

Tuber 0.496-0.529 V-10116 

50 WDG 1-2 34 <0.020 <0.020 <0.020 <0.020 NA 

Triazole Alanine 

Tuber 0.496-0.529 V-10116 

50 WDG 1-2 34 <0.020 0.075 0.075 0.031 0.016 

Total3

Tuber 0.496-0.529 V-10116 

50 WDG 1-2 34 <0.040 <0.040 <0.040 <0.040 NA 

1 Residues of total metconazole calculated as the sum of the cis- and trans- isomers. The LOQ was 0.04 ppm for 

potato 

2 All studies had PHIs of 1 day except for one study with a PHI of 2 days. 3

 Residues of total metconazole calculated as the sum of the cis- and trans- isomers. The LOQ was 0.04 ppm for potato. 

Conclusions: Pending review of the submitted triazole storage stability data, the submitted 

potato field trial data for metconazole are adequate to fulfill data requirements. 

 

The number and locations of field trials are in accordance with OPP Guideline 860.1500 for 

potato, the representative crop for the tuberous and corm vegetable subgroup 1C, and the use 

pattern of the field trials adequately reflects the proposed use pattern for tuberous and corm 

vegetables. Following four foliar broadcast applications of metconazole at a total rate of 0.496-

0.529 lb ai/A, total metconazole residues (cis-metconazole and trans-metconazole) in/on 

potatoes harvested at 1- to 2-day PHIs were below the LOQ (<0.04 ppm). Residue decline could 

not be determined for metconazole because all cis- and trans-metconazole residues were below 

the LOQ. Based on these low residues, the tolerance spreadsheet for setting tolerances was not 

utilized. The available field trial data will support a tolerance of 0.04 ppm for tuberous and corm 

vegetables subgroup 1C, reflecting the combined LOQs of the enforcement method of 0.02 ppm 

for each of the cis- and trans-isomers of metconazole. 

Residues of 1,2,4-triazole and triazole acetic acid in potato tubers were each <0.02 ppm. In 9 of 

the 17 field trials, residues of triazole alanine were detected in the treated samples at 020-0.075 

ppm (uncorrected); residues in the control were 0.006-0.069 ppm. In the residue decline study, 

residues of triazole alanine were observed in one of two sites, although a clear pattern of decline 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 16 of 27

could not be determined. The average triazole alanine residues (uncorrected) over the 14-day 

period ranged from 0.022-0.027 ppm and 0.013 ppm in the corresponding control. 

Blueberry 

The IR-4 submitted field trial data for metconazole residues in/on blueberry. Eleven blueberry 

field trials were conducted during the 2006 growing season; five trials in the United States on 

high bush blueberries in NAFTA Regions 2 (NJ and NC; 3 trials), 5 (MI; 1 trial), and 12 (OR; 1 

trial); six trials in Canada on low bush blueberries in NAFTA Regions 1 (New Brunswick; 1 

trial), 1A (Nova Scotia; 3 trials), 5A (Quebec; 2 trials). At each test location, there was one 

untreated and one treated plot. The treated plots received three foliar directed (high bush) or 

foliar broadcast (low bush) applications of V-10116 50WDG, a 50% water dispersible granular 

formulation of metconazole (a mixture of cis- and trans-metconazole (85/15 ratio) as the active 

ingredient). Applications were made at a target rate of 0.08 lb ai/A per application for a total 

seasonal rate of 0.24 lb ai/A. The first application was made at the bloom stage followed by retreatment intervals at 14 and 7 days before harvest. No adjuvant was added to the spray mixtures. 

Single control and duplicate treated samples of blueberries were harvested from each plot at preharvest intervals (PHI) of 6-8 days. At two of the test sites (06-MI32 and 06-NS01), one control 

and duplicate treated blueberry samples were also harvested at approximately 0, 1, 3, and 10 

days after the last application to determine residue decline. 

Following three foliar applications of metconazole at a total rate of 0.240-0.265 lb ai/A, 

metconazole residues (cis-metconazole and trans-metconazole) in/on blueberry at PHIs 6- to 8-

day were <0.010-0.326 ppm. Average metconazole residues in/on blueberry were 0.303 ppm. 

In the 06-MI32 and 06-NS01 residue decline trials, total mean metconazole residues declined 

steadily at longer post-treatment intervals in/on blueberry. For the 06-MI32 trial, total 

metconazole residues declined from a mean of 0.293 ppm at 0 day PHI to 0.183 ppm by 10 day 

PHI in highbush blueberries. For the 06-NS01 trial, total metconazole residues declined from a 

mean of 0.302 ppm at a 0-day PHI to 0.115 ppm by the 11-day PHI in lowbush blueberries 

Residues of the triazole metabolites were below the LOQ (<0.02 ppm) in/on all blueberry 

samples. 

The available field trial data will support a tolerance of 0.40 ppm for bushberry subgroup 13-07B 

as calculated utilizing the tolerance spreadsheet in the Agency’s Guidance for setting Pesticide 

Tolerances Based on Field Trial Data (Appendix I). 

The results of the blueberry field trials are summarized in Table 6. 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 17 of 27

Table 6. Summary of Residue Data from Blueberry Field Trials with a Metconazole Formulation 

(WDG).

Commodity Total 

Applic. Rate 

(lb ai/A) 

End-use 

Product

PHI 

(days)

Residue Levels (ppm)1 

n Min. Max. HAFT2 Mean3 Std. Dev. 

cis-Metconazole 

Berries 0.240-0.265 V-10116 

50 WDG 6-8 22 <0.05 0.263 0.246 0.110 0.1 

trans-Metconazole 

Berries 0.240-0.265 V-10116 

50 WDG 6-8 22 <0.05 0.063 0.056 0.051 0.0 

1,2,4-Triazole 

Berries 0.240-0.265 V-10116 

50 WDG 6-8 22 <0.02 <0.02 <0.02 <0.02 NA 

Triazole Acetic Acid 

Berries 0.240-0.265 V-10116 

50 WDG 6-8 22 <0.02 <0.02 <0.02 <0.02 NA 

Triazole Alanine 

Berries 0.240-0.265 V-10116 

50 WDG 6-8 22 <0.02 <0.02 <0.02 <0.02 NA 

Total4

Berries 0.240-0.265 V-10116 

50 WDG 6-8 22 <0.10 0.326 0.303 0.160 0.1 

1

Residues less than the LOQ were considered to be the LOQ for calculations. The lowest level of method validation (LLMV) is 

0.05 ppm for isomers of metconazole and 0.02 ppm for metabolites. Residue levels include residues of metconazole and 

metabolites. No conversion factors were applied. 2

HAFT = highest average field trial. 

3

 Mean and standard deviations were calculated by the study author. Does not include additional sampling intervals collected for 

the residue decline study. 

4 Residues of total metconazole calculated as the sum of the cis- and trans- isomers. The LOQ was 0.04 ppm 0.10 ppm for 

blueberry. 

Conclusions: Pending review of the submitted triazole storage stability data, the submitted 

blueberry field trial data for metconazole are adequate to fulfill data requirements. 

 

The number and locations of field trials are in accordance with the requirements of OCSPP 

Guideline 860.1500 for blueberry, the representative crop of the bushberry subgroup 13-07B, 

and the use pattern of the field trials adequately reflects the proposed use pattern for bushberries. 

Following three foliar applications of metconazole at a total rate of 0.240-0.265 lb ai/A, 

metconazole residues (cis-metconazole and trans-metconazole) in/on blueberry at PHIs 6- to 8-

day were <0.010-0.326 ppm. Residues of cis- and trans-metconazole declined with time. 

The available field trial data will support a tolerance of 0.40 ppm for bushberry subgroup 13-07B 

as calculated utilizing the tolerance spreadsheet in the Agency’s Guidance for setting Pesticide 

Tolerances Based on Field Trial Data (Appendix I). 

Residues of the triazole metabolites were below the LOQ (<0.02 ppm) in/on all blueberry 

samples. 

 

860.1520 Processed Food and Feed 

48143301.der2 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 18 of 27

:

Potato

IR-4 submitted a processing study for metconazole on potato. In two additional plots conducted 

in WA and TX field sites, a 50% WG formulation of metconazole was applied to potatoes at the 

exaggerated rates of 5x or 6.2x the maximum proposed seasonal application rate for tuberous and 

corm vegetables. Four foliar broadcast applications were made at 0.625 lb ai/A per application 

for a total seasonal rate of 2.5 lb ai/A (5x). An additional application was made at the TX trial 

site with a total seasonal rate of 3.1 lb ai/A (6.2x) due to scheduling at the processing facility. 

Potatoes were harvested at a 1-day PHI and processed into flakes/granules, chips, and wet peel 

by the University of Idaho Food Technology Center (Caldwell, ID) or the Texas A&M 

University Food Protein Research and Development Center (Bryan, TX) using simulated 

commercial procedures. Adequate descriptions of the processing procedures, including material 

balance summaries, were provided. 

Potato samples were analyzed for residues of metconazole isomers (cis- and trans-metconazole) 

and the triazole metabolites (T, TA, and TAA) using adequate methods. The LOQs were 0.04 

ppm for metconazole (0.02 ppm for each isomer), and 0.02 ppm for each of the triazole analytes. 

Sample storage conditions and durations are reported in Table 4. Adequate concurrent storage 

stability data were submitted to support the sample storage conditions and durations for analysis 

of metconazole; however, no storage stability data are available to support analysis for the 

triazole metabolites. 

Total metconazole residues (cis-metconazole and trans-metconazole) in/on potatoes harvested at 

1- to 2-day PHIs were below the LOQ (<0.04 ppm). Because residues were below the LOQ 

in/on potatoes treated at ~5x the maximum proposed seasonal application rate, processed 

fractions (flakes/granules, chips, and wet peel) were not analyzed. The theoretical concentration 

factor (based on loss of water; OPPTS 860.1520, Table 2) is 4.7x for potato flakes/granules. 

Residues of the triazole metabolites 1,2,4-T and TAA were below the LOQ (<0.02 ppm) in/on 

potato RAC samples from both sites; residues of TA were detected in potato from one site at 

0.066 ppm, and were below the LOQ at the other site. The residue data from the processing 

study is summarized in Table 7. 

Table 7. Residue Data from Potato Processing Study with Metconazole.

RAC Processed 

Commodity 

Total Rate 

(lb a.i./A) 

PHI 

(days) 

Residues (ppm) Proce

cismetcon

azole 

transmetcon

azole 

T TAA TA TA 

corrected 

Total 

metcon

azole 

cismetcon

azole 

transmetcon

azole 

T 

Prosser, WA; 2007 (07-WA33) 

Potato Tuber (RAC) 2.498 1 <0.020 <0.020 <0.020 <0.020 0.066 0.027 <0.040 -- -- -- 

Flakes NA NA NA NA NA NA NA NC NC NC 

Chips NA NA NA NA NA NA NA NC NC NC 

Wet peel NA NA NA NA NA NA NA NC NC NC 

Weslaco, TX; 2007 (07-TX28) 

Potato Tuber (RAC) 3.137 1 <0.020 <0.020 <0.020 <0.020 <0.020 -- <0.040 -- -- -- 

Flakes NA NA NA NA NA NA NA NC NC NC 

Chips NA NA NA NA NA NA NA NC NC NC 

Wet peel NA NA NA NA NA NA NA NC NC NC 

NA = Not analyzed. The LOQ was 0.020 ppm for metconazole and metabolites. 1

 NC = Not calculated; processed fractions were not analyzed.
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 19 of 27

Conclusions. Residues were below the LOQ in/on potato tubers following application of the 

WDG formulation at an exaggerated rate of 2.5 or 3.1 lb ai/A (5x or 6.2x the proposed seasonal 

application rate). An acceptable method was used for quantitation of residues in potato tubers. 

Adequate storage stability are available to support the sample storage conditions and durations 

for samples of potato tuber (RAC) for metconazole isomers (cis-metconazole and transmetconazole). The stability of the metabolites 1,2,4-triazole, triazole acetic acid, and triazole 

alanine under frozen conditions was not determined. Potato processed fractions were not 

analyzed. 

 

The submitted potato processing study is acceptable to satisfy data requirements. Because 

residues of metconazole were below the LOQ in/on samples of potato treated with metconazole 

at ≥5X the maximum proposed seasonal rate, analysis of processed samples is not required. 

HED concludes that quantifiable residues of metconazole in potato processed commodities are 

not expected, and separate tolerances are not needed. 

 

Available potato processing data for another triazole containing fungicide (difenoconazole) 

suggests that residues of difenoconazole do not concentrate in chips or granules/flakes (<0.01 

ppm; 0.5x average processing factor) but concentrate in wet peel (<0.01 and 0.03 ppm in 1x 

samples, and 0.04 and 0.32 ppm in 5x samples; 4x average processing factor). Residues of 1,2,4-

T and TAA were below the LOQ in/on all samples of potato RAC and its processed 

commodities. Residues of TA were 0.02 ppm in/on potato RAC samples treated at 1x, and 0.03 

and 0.05 ppm in/on potato RAC samples treated at 5x. The processing data indicate that TA do 

not concentrate in chips (<0.01-0.02 ppm; 0.4x average processing factor) or wet peel (<0.01 

ppm; 0.4x average processing factor) but concentrate in/on granule/flakes (0.01-0.05 ppm; 1.2x 

average processing factor). No storage stability data are available for the triazoles 1,2,4-T, TA, 

and TAA. (PP#6F7115, DP# 371264, W. Wassell, 8/9/07). 

860.1650 Submittal of Analytical Reference Standards 

An analytical standard for metconazole, with an expiration date of 9/1/2015, is currently 

available in the EPA National Pesticide Standards Repository (personal communication between 

T. Cole, ACB, and Versar, e-mail, 1/25/11). 

860.1900 Field Accumulation in Rotational Crops

DP#s 361110 and 361111, 2/26/10, D. Soderberg (PP#6F7094) 

DP#s 348168 and 348206, 2/20/08, N. Dodd (PP#6F7094 and PP#6F7095) 

No new field studies have been submitted. The earlier reviews required that end-use labels 

include plant-back restrictions of 30 days for leafy vegetables and Brassica leafy vegetables and 

120 days for all remaining crops other than those with labeled uses. This requirement has been 

fulfilled and the statement now appears in the master label. 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 20 of 27

860.1550 Proposed Tolerances

Tolerances are currently established for metconazole residues on plant commodities at levels 

ranging from 0.01-18 ppm and for residues of metconazole at 0.04 ppm in meat byproducts of 

cattle, goats, horses and sheep, and eggs [40 CFR §180.617]. No tolerances have been 

established for swine commodities. 

Permanent tolerances have been proposed by IR-4 for the combined residues of the fungicide 

metconazole in/or on the tuberous and corm vegetables subgroup 1C at 0.02 and the bushberry 

subgroup 13-07B at 0.35 ppm in/on bushberries. 

For purposes of the tolerance expression, HED has determined that the residue of concern is 

metconazole (the sum of cis- and trans- isomers) for both primary and rotational crops and for 

livestock commodities. The tolerance expression for metconazole in 40 CFR §180.617(a)(1) 

should be stated according to HED’s Interim Guidance on Tolerance Expression (5/27/09, S. 

Knizer) as follows: 

Tolerances are established for residues of metconazole, 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 metconazole [5-[(4-chlorophenyl)methyl]-2,2-

dimethyl-1-(1H-1,2,4-triazol-1-ylmethyl)cyclopentanol] as the sum of its cis- and trans-isomers. 

Adequate crop field trial data reflecting the proposed use patterns were submitted for purposes of 

establishing tolerances on the tuberous and corm vegetables subgroup 1C and the bushberry 

subgroup 13-07B. The tolerance spreadsheet in the Agency’s Guidance for Setting Pesticide 

Tolerances Based on Field Trial Data was utilized in determining the appropriate tolerance level 

for bushberries. The tolerance spreadsheet was not used to calculate the tolerance for tuberous 

and corm vegetables because residues in potato were below the LOQ (<0.04 ppm). The 

proposed tolerance of 0.02 ppm for tuberous and corm vegetables is too low. The tolerance 

should be established at 0.04 ppm, reflecting the combined LOQs of the metconazole 

enforcement method of 0.02 ppm for each of the cis- and trans- isomers of metconazole. The 

proposed tolerance of 0.35 ppm for bushberries is also too low; a tolerance must be proposed at 

0.40 ppm. 

Based on the results of the potato processing study, in which residues of metconazole were 

<LOQ in potatoes following application at ≥5x the maximum proposed seasonal rate, tolerances 

for the processed commodities of potato are not needed. 

There are currently no established Codex, Canadian, or Mexican maximum residue limits 

(MRLs) for metconazole on potato or blueberry. An International Residue Limit (IRL) status 

sheet is attached (Appendix I). 

The proposed and recommended tolerances for metconazole as a result of the subject action are 

presented in Table 8. The proposed tolerances should be revised to reflect the approved 

tolerance definition specified above, and the correct commodity definition and trecommended 

tolerance levels as specified in Table 8. 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 21 of 27

Table 8. Tolerance Summary for Metconazole. 

Commodity Proposed Tolerance 

(ppm) 

Recommended Tolerance 

(ppm) 

Comments 

(correct commodity definition) 

40 CFR §180.617(a)(2) 

Tuberous and Corm 

Vegetable subgroup 1C 

0.02 0.04 Vegetable, tuberous and corm, 

subgroup 1C 

Bushberry subgroup 13-07B 0.35 0.40

References

DP Number: 324541 

Subject: Metconazole. Request for a Tolerance on Imported Bananas. Summary of 

Analytical Chemistry and Residue Data. Petition Number 9E05052. 

From: N. Dodd 

To: M. Waller 

Date: 12/14/05 

MRIDs: 44721506, 44721507, 44721508, 44721509, 44721510, and 44721511 

DP#s: 303508 & 314517 

Subject: Prothioconazole. Petition for Establishment of Tolerances for Use on Barley, 

Oilseed (Except Sunflower and Safflower) Crop Group, Dried Shelled Pea and 

Bean (Except Soybean) Crop Subgroup, Peanut, Rice, and Wheat. Summary of 

Analytical Chemistry and Residue Data. PP#4F6830. 

From: S. Funk 

To: L. Coppolino 

Date: 8/21/06 

MRIDs: 46246139, 46246141-46246150, 46246201-46246211, 46246213-46246227, 

46477701-46477704 

DP Number: 371264 

Subject: PP#6F7115; Difenoconazole. Petition for Establishment of Tolerances on 

Fruiting Vegetables, Pome Fruit, Tuberous and Corm Vegetables, and Imported 

Papaya. Summary of Analytical Chemistry and Residue Data. 

From: W. Wassell and M. Sahafeyan 

To: D. Rosenblatt and Shaja Brothers 

Dated: 8/9/07 

MRID(s): 46950215-46950237 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 22 of 27

DP Number: 339992 

Subject: Review of Proposed Tolerance Enforcement Methods for Metconazole. ACB 

Project #: B07-18. 

From: P. Golden 

To: P. Deschamp 

Dated: 2/08/08 

MRID(s): 46902216, 46902217, 46665405, and 46665407 

DP Number: 339995 

Subject: Review of Proposed Tolerance Enforcement Methods for Metconazole. ACB 

Project #: B07-19. 

From: P. Golden 

To: P. Deschamp 

Dated: 2/15/08 

MRID(s): 46901704 and 46901706 

DP Number: 348234 

Subject: Metconazole. Report of the Residues of Concern Knowledgebase Subcommittee. 

From: C. Olinger 

To: Risk Assessment Team, RAB3 

Dated: 2/11/08 

MRID(s): None 

DP Numbers: 348168, 348206 

Subject: Metconazole. Petition for Establishment of Tolerances for Use on Small Grains, 

Stone Fruits, Tree Nuts, Peanuts, Soybeans, and Sugar Beets. Summary of 

Analytical Chemistry and Residue Data. PP#6F7094 and PP#6F7095. 

From: N. Dodd 

To: L. Coppolino/M. Waller 

Date: 2/20/08 

MRIDs: 46665405, 46665407, 46901704-46901712, 46901717, 46901902-46901909, 

46901912-46901915, 46902216-46902232, and 46902301-46902305 

DP Numbers: 350367 and 353357 

Subject: Metconazole. Petition for the Establishment of a Tolerance for Use on Canola. 

Summary of Analytical Chemistry and Residue Data. 

From: N. Dodd 

To: T. Keigwin/M. Waller 

Date: 9/18/08 

MRIDs: 47287801 and 47406901 

DP Numbers: 325956, 353372, and 360624 

Subject: Triticonazole. Application for New Seed Treatment Uses on Cereal Grains 

(Except Rice) (PP#8F7420). Summary of Analytical Chemistry and Residue 

Data. 

From: A.M. Acierto 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 23 of 27

To: Shaja Joyner 

Date: 6/12/09 

DP Numbers: 361110 and 361111 

Subject: Metconazole. Response to Data Gaps for Conditional Registration on Small 

Grains, Stone Fruits, Tree Nuts, Peanuts, Soybeans, and Sugar Beets. Summary 

of Analytical Chemistry and Residue Data. 

From: D. Soderberg 

To: M. Waller 

Date: 2/26/10 

MRIDs: 47621601, 47628002-47628006, and 47790001 

F. DOCUMENT TRACKING

RDI: A. M. Acierto (3/2/2011); ChemTeam (3/8/2011); S. Funk (3/24/2011) 

Petition Number: 0E7743 

DP#: 380990 

PC Code: 125619 

Attachments: 

Appendix I: International Residue Limits Status Sheet 

Appendix II: Tolerance Assessment Calculations. 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 24 of 27

Appendix 1

International Residue Limits 

Metconazole (PC Code 125619; 03/08/11) 

Summary of US and International Tolerances and Maximum Residue Limits 

Residue Definition: 

US Canada Mexico2 Codex3

40 CFR 180.617: 

Plants/Livestock: Metconazole [5-[(4-

chlorophenyl)methyl]-2,2-dimethyl-1-

(1H-1,2,4-triazol-1-

ylmethyl)cyclopentanol] as the sum of 

its cis- and trans- isomers 

None None 

Commodity1 Tolerance (ppm) /Maximum Residue Limit (mg/kg) 

US Canada Mexico2 Codex 

Vegetable, tuberous and corm, 

subgroup 1C 

0.04 

Bushberry subgroup 13-07B 0.4 

 

 

Completed: M. Negussie; 03/10/2011 

1

 Includes only commodities of interest for this action. Tolerance values should be the HED recommendations and 

not those proposed by the applicant. 

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

3 * = absent at the limit of quantitation; Po = postharvest treatment, such as treatment of stored grains. PoP = 

processed postharvest treated commodity, such as processing of treated stored wheat. (fat) = to be measured on the 

fat portion of the sample. MRLs indicated as proposed have not been finalized by the CCPR and the CAC. 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 25 of 27

Appendix II. Tolerance Assessment Calculations.

The dataset used to establish a tolerance for metconazole on bushberry subgroup 13-07B 

consisted of field trial data representing application rates of 0.240-0.265 lb ai/A (3 applications at 

~0.08 lb ai/A/application) with a 6- to 8-day PHI. As specified by the Guidance for Setting 

Pesticide Tolerances Based on Field Trial Data (SOP), the field trial application rates and PHIs 

are generally within 25% of the maximum label application rate and minimum label PHI, 

respectively. The residue values that were entered into the tolerance spreadsheet (August 2009 

version) are provided in Table II-1. 

Because 4 of the 22 field trial sample results (18%) were below the LOQ (LOQ = 0.10 ppm for 

total metconazole residues), maximum likelihood estimation (MLE) procedures were needed to 

impute censored values. The dataset was large (>15 samples). Visual inspection of the 

lognormal probability plot (Figure II-1) and the results from the approximate Shapiro-Francia 

test statistic (Figure II-2) indicated that the dataset was reasonably lognormal. 

Since the field trial data for metconazole on blueberry represent a large dataset (i.e., more than 

15 samples) and are reasonably lognormal, the minimum of the 95% upper confidence limit 

(UCL) on the 95th percentile and the point estimate of the 99th percentile should be selected as 

the tolerance value. Using the rounding procedure as outlined in the SOP, the 95% UCL on the 

95th percentile and the point estimate of the 99th percentile round to the value 0.40 ppm (Figure 

II-2); therefore, 0.40 ppm is the recommended tolerance level for metconazole on bushberries. 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 26 of 27

Table II-1. Residue data used to calculate tolerance for metconazole on 

blueberry.

Regulator: EPA 

Chemical: Metconazole 

Crop: Blueberry (MLE) 

PHI: 7 Days 

App. Rate: 0.234 lb ai/A 

Submitter: IR-4 

MRID Citation: MRID 48143302 

 Residues of Metconazole (ppm) 

 0.0721

 0.0821

 0.124 

 0.137 

 0.204 

 0.180 

 0.0891

 0.0951

 0.156 

 0.244 

 0.140 

 0.140 

 0.326 

 0.280 

 0.170 

 0.142 

 0.141 

 0.143 

 0.170 

 0.191 

 0.126 

 0.115 

1

 Value calculated using the MLE spreadsheet. 
Metconazole Summary of Analytical Chemistry and Residue Data DP#: 380990 

Page 27 of 27

Figure II-1. Lognormal probability plot of metconazole field trial data for blueberry. 

0.1 1 2 5 10 20 30 50 70 80 90 95 98 99 99.9

1.0000

0.5000

0.2500

0.1250

0.0625

y = 0.3856x - 1.917

R2 = 0.9757

Concentrations

Percentiles

Lognormal Probability Plot

EPA Metconazole Blueberries (MLE) 7 Days 0.234 lb ai/A IR-4...

Figure II-2. Tolerance spreadsheet summary of metconazole field trial data for blueberry. 

Regulator: EPA

Chemical: Metconazole

Crop: Blueberries (MLE)

PHI: 7 Days

App. Rate: 0.234 lb ai/A

Submitter: 48143302

n: 22

min: 0.07

max: 0.33

median: 0.14

average: 0.16

95th Percentile 99th Percentile 99.9th Percentile

0.30 0.35 0.40

(0.35) (0.40) (--)

0.30 0.40 0.50

(0.40) (0.50) (--)

0.40

0.35

0.80

0.9757

p-value > 0.05 : Do not reject lognormality assumption

Approximate 

Shapiro-Francia 

Normality Test 

EU Method I

Normal

UCLMedian95th

95/99 Rule

EU Method II

Distribution-Free

Mean+3SD