Document ID: EPA-HQ-OPP-2008-0773-0007
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-12-18T05:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

	OFFICE OF PREVENTION, PESTICIDES

	AND TOXIC SUBSTANCES

  SEQ CHAPTER \h \r 1 MEMORANDUM

Date:  		08/05/2009

SUBJECT:	Prometryn.  Registration Request to Add New Uses on Carrot,
Celeriac, Cilantro, Okra, and Parsley.  Summary of Analytical Chemistry
and Residue Data.

PC Code:  080805	DP Barcode:  D357094

Decision No.:  400395	Registration Nos.:  100-620 & 66222-15

Petition No.:  8E7434	Regulatory Action:  Amended Section 3

Risk Assessment Type:  NA	Case No.:  0467

TXR No.:  NA	CAS No.:  7287-19-6

MRID Nos.:  47548701 through 47548705	40 CFR:  §180.222

From:		William D. Wassell, Chemist

		Risk Assessment Branch 1 (RAB1)

		Health Effects Division (HED, 7509P)

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

	RAB1/HED (7509P)

To:		William D. Wassell, Risk Assessor

		RAB1/HED (7509P)

				and

				Susan Stanton/Daniel Rosenblatt, RM 05

	Registration Division (RD; 7505P)

  SEQ CHAPTER \h \r 1 This document was originally prepared under
contract by Dynamac Corporation (1901 Research Boulevard, Suite 220;
Rockville, MD 20850).  This document has been reviewed by HED and
revised to reflect current Office of Pesticide Programs (OPP) policies.

Executive Summary

Prometryn [2,4-bis(isopropylamino)-6-methylthio-s-triazine] is a
substituted thiomethyl triazine herbicide (Group 5) registered in the
U.S. for the control of weeds in celery, cotton, dill, and pigeon peas. 
Prometryn is a List A chemical.  The Prometryn Reregistration
Eligibility Decision (RED) document was issued February 1996.  The
Product and Residue Chemistry Chapters for the Prometryn RED were issued
12/8/94.

The Interregional Research Project No. 4 (IR-4), on behalf of the
Agricultural Experiment Stations of CA, GA, IA, MI, MN, MS, NC, NJ, NY,
OH, OR, SC, TN, and TX, has submitted a tolerance petition and Section 3
registration request for new uses of prometryn on carrot, celeriac,
cilantro, okra, and parsley.  The end-use products (EUPs) relevant to
this registration request are Prometryn 4L Herbicide (EPA Reg. No.
66222-15) and Caparol® 4L (EPA Reg. No. 100-620).  These products are
formulated as flowable-concentrates (FlC) and contain 44.0-44.4%
prometryn (equivalent to 4.0 pound active ingredient per gallon (lb
ai/gal)).  They are proposed for preemergence and/or postemergence
broadcast applications using ground equipment with maximum seasonal
rates of 1.5 lb ai per acre (A) for okra, 1.6 lb ai/A for cilantro, 2.0
lb ai/A parsley, 4.0 lb ai/A for celeriac, and 6.0 lb ai/A for carrot. 
Depending on the crop, the proposed pre-harvest intervals (PHIs) range
from 14 to 60 days.  In conjunction with these uses, IR-4 proposes the
establishment of permanent tolerances for residues of prometryn per se
in/on the following:

Carrot	0.7 ppm

Celeriac, roots	0.05 ppm

Celeriac, tops	0.05 ppm

Cilantro (fresh)	4.0 ppm

Cilantro (dry)	15 ppm

Okra	0.05 ppm

Parsley, leaves	0.7 ppm

The petitioner concurrently requests the deletion of the established
tolerance for residues of prometryn per se in/on parsley, leaves with
regional exemption under 40 CFR §180.222(c).

Tolerances have been established for residues of prometryn per se in/on
carrot roots (tolerance with no U.S. registration) at 0.1 ppm, and in/on
celery, corn grain, cotton seed, and pigeon peas at 0.25-0.5 ppm [40 CFR
§180.222(a)].  Regionally restricted tolerances have been established
for prometryn residues in/on dill at 0.3 ppm and parsley leaves at 0.1
ppm [40 CFR §180.222(c)].

The nature of the residue in plants is understood for registered uses
based on acceptable cotton and celery metabolism studies.  HED has
tentatively determined that, for purposes of this petition, residues of
concern in plant commodities consist of the parent, prometryn per se,
which is the currently regulated residue.  The available cotton and
celery metabolism data are adequate to support the proposed uses on
cilantro, okra, and parsley; however, no data are available reflecting
metabolism in a root crop to support the proposed uses on carrot and
celeriac.  A metabolism study reflecting application of prometryn to
carrot or another root crop is now required as a condition of
registration.  

The nature of the residue in livestock is adequately understood based on
acceptable poultry and ruminant metabolism studies.  The residue of
concern (and that which should be regulated) in livestock is the parent,
prometryn per se.  As in plant commodities, the metabolism of prometryn
in livestock involves N-dealkylation along with hydrolysis and/or amino
acid conjugation.

Adequate enforcement methodology is available to enforce the proposed
tolerances.  Prometryn is completely recovered (>80% recovery) using the
Food and Drug Administration’s (FDA’s) Multiresidue Section 302.  In
addition, an acceptable gas chromatography (GC) method with
flame-photometric detection in the sulfur mode (FPD/S), Ciba-Geigy
Method AG-559, is available for use as a single-analyte confirmatory
method.  

Samples of carrot, celeriac, cilantro, okra, and parsley from the
magnitude of the residue studies were analyzed for residues of prometryn
and the triazine impurities GS-11354 and GS-26831 using methods derived
from Method AG-559.  Samples of carrot root, celeriac root and tops, and
parsley were analyzed using a GC/FPD/S version of the method, and
samples of cilantro were analyzed using a version with high-performance
liquid chromatography and tandem mass spectrometry detection
(HPLC/MS/MS).  For the GC/FPD/S method, the lowest limit of method
validation (LLMV) was 0.05 ppm for each analyte in all matrices, and for
the HPLC/MS/MS method, the LLMV was 0.02 ppm for each analyte in/on
fresh cilantro and 0.05 ppm in/on dried cilantro.  The methods were
generally adequate for data collection based on method verification and
concurrent method validation recoveries.

The 1994 Residue Chemistry Chapter concluded that residues of prometryn
per se in meat and milk can be classified under Category 3 of 40 CFR
§180.6(a).  That is, there is no reasonable expectation of finite
residues in meat and milk.  No tolerances were required in the Residue
Chapter, and therefore, livestock feeding studies were not required.  In
the current petition, the only livestock feedstuff is carrot culls which
may contribute up to 10% in dairy cow diets only.  Pending submission of
additional plant metabolism and crop field trial data, HED tentatively
concludes that the Category 3 situation remains valid for this
registration request.  Because there are no established or proposed
tolerances for prometryn residues in livestock commodities, feeding
studies are not required at this time and an enforcement method for
livestock commodities is also not required. 

The submitted crop field trial and processing data are supported by
adequate storage stability data.  These data show that corrections for
storage degradation of residues are not required for the submitted
studies.

Pending submission of additional crop field trial data for carrot (3
trials) and parsley (1 trial), and revision of the proposed use pattern
for celeriac, cilantro, and parsley, adequate field trial data have been
submitted to support the proposed uses on carrot, celeriac, cilantro,
okra, and parsley.  The submitted data will support the proposed
tolerances for residues at the limit of quantification (LOQ) for
celeriac root and okra at 0.05 ppm.  The data indicate that the proposed
tolerances for residues in/on carrot, cilantro, and parsley are too high
and will support tolerance levels of 0.45 ppm for residues in/on carrot
roots, 3.5 ppm for residues in/on cilantro leaves, 9.0 ppm in/on
coriander, dried leaves, and 0.60 ppm in/on parsley leaves.  A higher
tolerance is also required for residues in/on celeriac tops at 0.20 ppm.

Cilantro and parsley are also considered herb crops for which the dried
crop is the processed commodity.  Adequate processing data are available
for cilantro and these data will be translated to parsley.  The
submitted data indicate that the proposed tolerance for residues in/on
dried cilantro is too high.  The available data will support a tolerance
for residues at 9.0 ppm for coriander, dried leaves and a tolerance for
residues at 1.5 ppm for parsley, dried leaves.  A revised Section F is
required. 

The nature of the residue in rotational crop is adequately understood. 
The metabolism of prometryn in rotational crops is similar to that in
primary crops.  Acceptable field rotational crop data are available to
support limited crop rotation, pending resolution of deficiencies
identified under DP#s 315763 & 357098 (currently under review)
concerning the soil characteristics and sample harvest and handling
procedures in the most recent study.  The available data will support
the following minimum plantback restrictions for crops not listed on the
labels:  (1) Following application to any primary crop at up to 3.2 lb
ai/A:  a 5-month PBI for leafy vegetables, an 8-month PBI for root
crops, and a 9-month PBI for small grains and all other crops and (2)
following application at rates higher than 3.2 lb ai/A and up to 6.0 lb
ai/A:  an 8-month PBI for root crops; rotation to all other crops is
prohibited.

There are currently no established Codex maximum residue limits (MRLs)
for prometryn.  No Canadian MRLs have been established for prometryn,
although prometryn is registered for use in Canada on carrots, celery,
leeks, and peas.  These uses presumably fall under the Pest Management
Regulatory Agency (PMRA) of Health Canada General MRL of 0.1 mg/kg.
Mexican MRLs have been established for residues of prometryn in/on corn,
cotton, and pea at 0.25 ppm, and celery at 0.5 ppm.

Analytical standards for prometryn are currently available in the EPA
National Pesticide Standards Repository.

  SEQ CHAPTER \h \r 1 Regulatory Recommendations and Residue Chemistry
Deficiencies

Pending submission of a revised Section B (see requirements under
Directions for Use) and a revised Section F (see requirements under
Proposed Tolerances), there are no residue chemistry issues that would
preclude granting conditional registration for the requested uses or the
establishment of tolerances for residues of prometryn per se as follow:

Carrot, roots	0.45 ppm*

Celeriac, roots	0.05 ppm

Celeriac, tops	0.20 ppm

Cilantro, leaves	3.5 ppm

Coriander, dried leaves	9.0 ppm

Okra	0.05 ppm

Parsley, leaves	0.60 ppm*

Parsley, dried leaves	1.5 ppm.

*Note to PM:  Concurrent with the establishment of the proposed
tolerance for residues in/on carrot roots, the tolerance without U.S.
registration for residues in/on carrot should be removed.  Concurrent
with the establishment of the proposed tolerance for residues in/on
parsley leaves, the tolerance with regional exemption under 40 CFR
180.222(c) for residues in the same commodity should be removed.

A human-health risk assessment is forthcoming.

860.1200 Directions for Use

For celeriac, the directions for use should be revised to specify that
postemergence application may be made to plants up to the 6- to 8-leaf
stage.  For celeriac, the directions should be revised to specify that
postemergence application may be made to plants up to the 6- to 8-leaf
stage.  Additionally, the Section B indicates a maximum of 1 application
at up to 4.0 lb ai/A for Carparol 4L; however, the proposed label for
Carparol 4L indicates a maximum rate of 4 pints per acre (2 lb ai/A) and
the proposed label for Prometryn 4L indicates a maximum application rate
of 4 lb ai/A.  The residue data support an application rate of 4.0 lb
ai/A.  A revised Section B (proposed labels) should be submitted that
indicates a maximum application rate of 4 lb ai/A for Carparol 4L on
celeriac.

For cilantro, the directions should be revised to specify preemergence
application.  Additionally, the Section B indicates a maximum of 1
application at up to 1.6 lb ai/A for Carparol 4L; however, the proposed
label for Carparol 4L indicates a maximum rate of 3.4 pints per acre
(1.7 lb ai/A) and the proposed label for Prometryn 4L indicates a
maximum application rate of 4 lb ai/A.  The residue data support an
application rate of 1.6 lb ai/A.  A revised Section B (proposed labels)
should be submitted that indicates a maximum application rate of 1.6 lb
ai/A for Carparol 4L and Prometryn 4L on cilantro.

For parsley, the directions for use should be revised to reflect the use
pattern specified on the draft label for Caparol® 4L:  Preemergence
application is to be made up to 14 days after planting; the first
postemergence application may be made up to 30 days pre-harvest, and the
second postemergence application may be made to regrowth up to 30 days
prior to the second (cutting) harvest.  

For use on parsley, the product label for Prometryn 4L Herbicide should
be revised to restrict preemergence application at 1.0-2.0 lb ai/A to
parsley grown in CA only.

The product label for Caparol® 4L Herbicide should be revised to remove
instructions for use of surfactants for applications to okra.

The following minimum rotational crop restrictions are required for all
crops not listed on the label:  (1) Following application to any primary
crop at up to 3.2 lb ai/A:  a 5-month PBI for leafy vegetables, an
8-month PBI for root crops, and a 9-month PBI for small grains and all
other crops and (2) following application at rates higher than 3.2 lb
ai/A and up to 6.0 lb ai/A:  an 8-month PBI for root crops; rotation to
all other crops is prohibited.

860.1550 Proposed Tolerances

The petitioner should submit a revised Section F to specify the
reassessed tolerances and to reflect the correct commodity definition
listed in Table 11.

HED recommends conversion of conditional registration to unconditional
registration for the requested crops be contingent upon submission of
the outstanding residue chemistry data pertaining to plant metabolism,
crop field trials, and field accumulation in rotational crops:

860.1300 Nature of the Residue - Plants

A metabolism study reflecting application of prometryn to carrot or
another root crop is requested.

860.1500 Crop Field Trials

Carrot:  Three additional carrot trials are requested in Zones 5, 10,
and 11 reflecting application according to the maximum proposed use
pattern, including use of a surfactant; one of the trials should
generate residue decline data.  

860.1900 Field Accumulation in Rotational Crops

Additional information is required concerning the soil characteristics
and sample harvest and handling procedures at the CA and MS sites for
the study reported in MRID 45190601 (refer to DP#s 357098 and 315763,
currently under review).

Background

The chemical structure and nomenclature of prometryn and the triazine
impurities GS-11354 and GS-26831 are presented in Table 1.  The
physicochemical properties of the technical grade of prometryn are
presented in Table 2.

Table 1. Prometryn Nomenclature.

Chemical structure	

Common name	Prometryn

Company experimental name	G-34161

IUPAC name	N,N'-diisopropyl-6-(methylthio)-1,3,5-triazine-2,4-diamine

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

CAS registry number	7287-19-6

End-use product (EP)	Caparol® 4L (4 lb/gal FlC; EPA Reg. No. 100-620)

Prometryn 4L Herbicide (4 lb/gal FlC; EPA Reg. No. 66222-15)

Triazine Impurity

 

2-amino-4-iospropylamino-6-methylthio-s-triazine

Triazine impurity

 

2,4-bis-amino-6-methylthio-s-triazine

Table 2.	   Physicochemical Properties of Prometryn.

Parameter	Value	Reference

Melting range	118-120(C	DP# 207139, 12/8/94, C. Swartz

pH	6.7 at 20ºC (saturated solution)	RCB# 2907, 12/4/87, G. Makhijani

Density	1.16 g/mL at 20ºC

	Water solubility	33 ppm at 20ºC	DP# 207139, 12/8/94, C. Swartz

Solvent solubility	10-30 g/100 mL in acetone,

dichloromethane, methanol, 

octanol, and toluene at 20ºC

	Vapor pressure	8.54 x 10-7 mm Hg at 25ºC	DP#s 196116 & 196123,
4/25/94, K. Dockter

Dissociation constant, pKa	4.09 at 20ºC	RCB# 2907, 12/4/87, G.
Makhijani

Octanol/water partition coefficient	KOW = 2140 at 25ºC	DP#s 196116 &
196123, 4/25/94, K. Dockter

UV/visible absorption spectrum	Not available.

	

860.1200 Directions for Use

The EUPs relevant to this registration action are Prometryn 4L Herbicide
(EPA Reg. No. 66222-15) registered to Makhteshim Agan, and Caparol® 4L
(EPA Reg. No. 100-620) registered to Syngenta.  These products are
formulated as FlCs and contain 44.0-44.4% prometryn (equivalent to 4.0
lb ai/gal).  

A summary of the proposed use directions for prometryn on the requested
crops (carrot, celeriac, cilantro, okra, and parsley) is presented in
Table 3.  The petitioner submitted a Section B and draft labeling for
both products.  HED notes that there are minor differences in the draft
labeling between the two products with respect to certain application
types and timing, application volumes, and maximum use rates for
selected crops, etc.  Except as noted below, the use directions
presented in Table 3 reflect those presented in Section B.

Table 3.   Summary of Directions for Use of Prometryn.

Application Timing,

Application Type,

Equipment (Gallons per Acre; GPA)1	Product

[EPA Reg. No.]	Applic. Rate

(lb ai/A)	Max. No. Applic. per Season	Max. Seasonal Applic. Rate

(lb ai/A)	PHI

(days)

Carrot

Preemergence and/or

   postemergence

Broadcast

Ground (≥20 GPA)	Caparol® 4L

[100-620]

Prometryn 4L 

[66222-15]	1.0-2.0	Up to 3:  1 preemergence + two postemergence	6.0	30

	Use Directions and Limitations:  Postemergence application should not
be made beyond the crop’s 6-leaf stage.  A surfactant may be used as
part of the tank mix.

Celeriac

Not specified2

Broadcast

Ground (≥10 GPA)	Caparol® 4L

[100-620] 

Prometryn 4L 

[66222-15]	4.0	1	4.0	60

	Use Directions and Limitations:  None specified.

The draft labeling for Caparol® 4L specifies that application is to be
made to transplants, and is to be “after the crop has 6-8 leaves.”

Cilantro

Not specified2

Broadcast

Ground (≥10 GPA)	Caparol® 4L

[100-620] 

Prometryn 4L 

[66222-15]	1.6	1	1.6	30

	Use Directions and Limitations:  None specified.

The draft labeling for Caparol® 4L specifies that application may be
made post planting and preemergence.  Application to sand or loamy sand
soils is prohibited.

Okra

Preemergence/Post-directed

Broadcast

Ground (≥20-40 GPA)	Caparol® 4L

[100-620]

Prometryn 4L 

[66222-15]	0.75-1.50	1 preemergence at 1.5 lb ai/A

or

2 at 0.75 lb ai/A per application:  one preemergence + one post-directed
	1.5	14

	Use Directions and Limitations:  When two applications are made, the
second application is to be made to plants at the 7- to 9-leaf stage. 
The Caparol® 4L allows use of a surfactant as part of the tank mix.

Parsley

Not specified2

Broadcast

≥10 GPA)	Caparol® 4L

[100-620]

Prometryn 4L

 [66222-15]	0.5	2/crop cycle	1.0 per crop cycle 

or 1.5 lb ai/A per year	30

	Use Directions and Limitations: None specified.

Preemergence/ Postemergence

Broadcast

Ground (≥20 GPA)	Draft

label only: Caparol® 4L

[100-620]	0.5-2.0	1 preemergence	1	NS

Use Directions and Limitations:  For use in CA only.  If a rate higher
than 0.5 lb ai/A is applied, then only one application is allowed. 
Application to sand or loamy sand soils is prohibited.

0.5	Up to 3:  1 preemergence +  two postemergence	1.5	30

Use Directions and Limitations:  For use in all states (including CA). 
Preemergence application is to be made up to 14 days after planting; the
first postemergence application may be made up to 30 days pre-harvest,
and the second postemergence application may be made to regrowth up to
30 days prior to the second (cutting) harvest.  Application to sand or
loamy sand soils is prohibited.

Preemergence

Broadcast

Ground (20 GPA)	Draft

label only: Prometryn 4L

 [66222-15]	1.0-2.0	1 preemergence	NS	NS

Use Directions and Limitations:  Application to sand or loamy sand soils
is prohibited.

1  Equipment type was not specified in Section B.  Based on the
recommended spray volumes, ground equipment was implied.  The draft
labeling specifies aerial application to cotton and/or pigeon peas only.

2  For celeriac, cilantro, and parsley, Section B specifies only that
broadcast applications may be made, but does not specify application
type.

HED notes that Section B and the draft labeling for Prometryn 4L specify
use of a surfactant for applications to carrots only; the draft labeling
for Caparol® 4L includes instructions for use of surfactants for
applications to carrots and okra.

Rotational crop restrictions were not specified in Section B of the
petition.  The draft labeling for Caparol® 4L specifies the following
plantback restrictions following maximum applications to carrot, okra,
and parsley at  ≤2 lb ai/A and cilantro at ≤1.7 lb ai/A:  5 months
for cabbage, carrots, celery, corn, cotton, dill, fennel, okra, and
peas; 8 months for onions and red beets; and 12 months for all other
crops.  No rotational crop restrictions are specified for celeriac.  For
Prometryn 4L, the following rotational crop restrictions are specified
for parsley only:  5 months for cabbage, celery, corn, cotton, and peas;
and 8 months for onions and red beets.

Conclusions:  The proposed use directions are adequate to allow
evaluation of the residue data relative to the proposed use.  Provided
Section B is revised as specified below, the submitted field trial data
will support the proposed uses on carrot, celeriac, cilantro, okra, and
parsley; however, additional field trial data are required for carrot
and parsley.  

For celeriac, cilantro, and parsley, the proposed use directions under
Section B are too general.  For celeriac, the directions should be
revised to specify that postemergence application may be made to plants
up to the 6- to 8-leaf stage.  Additionally, the Section B indicates a
maximum of 1 application at up to 4.0 lb ai/A for Carparol 4L; however,
the proposed label for Carparol 4L indicates a maximum rate of 4 pints
per acre (2 lb ai/A) and the proposed label for Prometryn 4L indicates a
maximum application rate of 4 lb ai/A.  The residue data support an
application rate of 4.0 lb ai/A.  A revised Section B (proposed labels)
should be submitted that indicates a maximum application rate of 4 lb
ai/A for Carparol 4L on celeriac.

For cilantro, the directions should be revised to specify preemergence
application.  Additionally, the Section B indicates a maximum of 1
application at up to 1.6 lb ai/A for Carparol 4L; however, the proposed
label for Carparol 4L indicates a maximum rate of 3.4 pints per acre
(1.7 lb ai/A) and the proposed label for Prometryn 4L indicates a
maximum application rate of 4 lb ai/A.  The residue data support an
application rate of 1.6 lb ai/A.  A revised Section B (proposed labels)
should be submitted that indicates a maximum application rate of 1.6 lb
ai/A for Carparol 4L and Prometryn 4L on cilantro.

For parsley, the directions for use should be revised to reflect the use
pattern specified on the draft label for Caparol® 4L:  Preemergence
application is to be made up to 14 days after planting; the first
postemergence application may be made up to 30 days pre-harvest, and the
second postemergence application may be made to regrowth up to 30 days
prior to the second (cutting) harvest.  

The draft labeling for both products reflects preemergence application
to carrot at up to 2.0 lb ai/A; this use pattern is limited to CA on the
draft label for Caparol® 4L, but the specification for “California
Only” has been crossed out on the draft label for Prometryn 4L. 
Previously submitted data are available to support preemergence
application to parsley in CA only at up to 2.0 lb ai/A.  The
instructions for preemergence application at 1.0-2.0 lb ai/A to parsley
should be restricted to parsley grown in CA for Prometryn 4L.

The available field trial data will support use of a surfactant for
applications to carrot only.  The instructions for use of surfactants
for applications to okra should be removed from the product label for
Caparol® 4L.  Additionally, a statement prohibiting the use of
surfactants in the spray solutions for use on celeriac, cilantro, okra,
and parsley should be added to the labels.

The available rotational crop data for prometryn are not sufficient to
support rotation to crops other than root crops at application rates
higher than 3.2 lb ai/A.  Therefore, for all crops not listed on the
label, the following minimum rotational crop restrictions are required: 
(1) Following application to any primary crop at up to 3.2 lb ai/A:  a
5-month PBI for leafy vegetables, an 8-month PBI for root crops, and a
9-month PBI for small grains and all other crops.  (2) Following
application at rates higher than 3.2 lb ai/A and up to 6.0 lb ai/A:  an
8-month PBI for root crops; rotation to all other crops is prohibited.

860.1300 Nature of the Residue - Plants

Residue Chemistry Chapter of the Prometryn RED, DP# 207139, 12/8/94, C.
Swartz

Acceptable cotton and celery metabolism studies were previously
reviewed.  The 1994 Residue Chemistry Chapter concluded that the
qualitative nature of the residue in plants was adequately understood
for the registered/proposed uses at that time (including registered uses
on celery, cotton, and pigeon peas, and proposed uses on parsley, dill,
and sesame).  The results of the metabolism studies showed metabolic
pathways involving N-dealkylation and hydrolysis of prometryn.  HED
determined that the residue of concern in plants consists of the parent,
prometryn per se, which is the currently regulated residue.  HED
concluded that if other major uses were registered in the future,
additional metabolism studies would be required.

Conclusions:  For the purposes of this petition, HED tentatively
concludes that prometryn per se is the residue of concern for tolerance
enforcement and risk assessment purposes in carrot, celeriac, cilantro,
okra, and parsley.  

The available cotton and celery metabolism data are adequate to support
the proposed uses on cilantro, okra, and parsley; however, no data are
available reflecting metabolism in a root crop to support the proposed
uses on carrot and celeriac.  OPPTS 860.1300 specifies that a metabolism
study should be submitted for each type of plant for which use is
proposed or metabolism studies on three dissimilar crops must be
provided which indicate a similar metabolic route. 

HED notes that the Agency previously approved the establishment of a
tolerance for residues in/on carrot without a U.S. registration (DP#s
237148 and 224645, 1/20/98, W. Wassell, et al.) in support of use of
prometryn in Canada.  HED concluded at that time that a carrot
metabolism study was not required to support the proposed use because of
the low residue levels found in the field trials (<0.1 ppm), noting that
the Agency prefers to require metabolism studies for uses that result in
detectable residues to assure adequate identification of the residue.

Based on the submitted field trial data, the proposed use on carrots and
celeriac resulted in detectable residues up to 0.282 ppm in carrot root
and 0.051 ppm in celeriac root.  A metabolism study reflecting
application of prometryn to carrot or another root crop is now required.
 Fulfillment of this data gap may be considered a condition of the
registration requested in this action.

860.1300 Nature of the Residue - Livestock

Residue Chemistry Chapter of the Prometryn RED, DP# 207139, 12/8/94, C.
Swartz

The nature of the residue in livestock is adequately understood based on
acceptable poultry and ruminant metabolism studies.  The residue of
concern (and that which should be regulated) in livestock is the parent,
prometryn per se.  As in plants, the metabolism of prometryn in
livestock involves N-dealkylation along with hydrolysis and/or amino
acid conjugation.

860.1340 Residue Analytical Methods

Residue Chemistry Chapter of the Prometryn RED, DP# 207139, 12/8/94, C.
Swartz

Enforcement methods:    SEQ CHAPTER \h \r 1  Adequate enforcement
methodology is available to enforce the proposed tolerances.  Prometryn
is completely recovered (>80% recovery) using FDA’s Multiresidue
Section 302.

In addition, an acceptable GC/FPD/S method, Ciba-Geigy Method AG-559, is
available for use as a single analyte confirmatory method.  Method
AG-559 has undergone a successful independent laboratory validation and
was radiovalidated using samples from the celery metabolism study;
however, these samples contained no detectable residues of prometryn. 
HED previously concluded that Method AG-559 is acceptable for
enforcement purposes, pending completion of a successful Agency method
validation trial and submission of additional radiovalidation data.  

Data collection methods:  Samples of carrot, celeriac, okra, parsley,
and cilantro from the magnitude of the residue studies were analyzed for
residues of prometryn and the triazine impurities GS-11354 and GS-26831
using methods derived from Method AG-559.  

Samples of carrot root, celeriac root and tops, and parsley were
analyzed using a GC/FPD/S version of Method AG-559.  Samples were
extracted by refluxing for 1 hour with methanol:water (9:1, v:v),
cooled, and filtered.  The extract was concentrated, acidified with 1 N
HCl, filtered again, and diluted with water.  Sodium phosphate was
added, and the pH was adjusted to 9.5-10 with 50% NaOH.  Residues in the
basic extract were then partitioned into ethyl acetate.  The ethyl
acetate phase was dried over Na2SO4, evaporated to dryness, and
redissolved in ethyl acetate (or simply concentrated) for analysis by
GC/FPD in the sulfur mode.  Parent prometryn and its metabolites are
quantitated individually.  The LLMV was 0.05 ppm for each analyte in all
matrices.  

Samples of cilantro were analyzed using an LC/MS/MS version of Method
AG-559.  Samples were extracted by refluxing for 1 hour with
methanol:water (9:1, v:v), cooled, and filtered.  The extract was
concentrated, acidified with 1 N HCl, evaporated to remove the methanol,
and partitioned with hexane.  The aqueous layer was made basic and
cleaned up through a Chem Elut solid-phase extraction (SPE) cartridge. 
Residues were eluted from the SPE column with dichloromethane.  Residues
in the eluate were concentrated (evaporated to dryness) and redissolved
in 50% methanol/(10 mM ammonium acetate/water) for analysis by
HPLC/MS/MS.  Parent prometryn and the triazine metabolites were
quantitated individually.  The LLMV was 0.02 ppm for each analyte in/on
fresh cilantro and 0.05 ppm in/on dried cilantro.  

The GC/FPD/S and HPLC/MS/MS methods were adequately validated prior to
and concurrently with the analysis of treated samples.  The
fortification levels were adequate to bracket residues found in treated
samples.  Method verification and concurrent method recoveries were
generally within the acceptable range of 70-120% for carrot root,
celeriac root and tops, okra, and parsley fortified with each analyte at
0.05-0.5 ppm, and for cilantro fortified with each analyte at 0.02-4 ppm
(fresh) or 0.05-10 ppm (dried).  

Conclusions:  The submitted residue analytical methods data are adequate
to satisfy data requirements for the subject action.  Acceptable
enforcement methodology is available for tolerance enforcement purposes
for the proposed uses, and adequate GC/FPD/S and HPLC/MS/MS methods were
used for data collection in the submitted field trial studies.

860.1360 Multiresidue Methods

The FDA PESTDATA database (dated 06/05) indicates that prometryn is
completely recovered (>80% recovery) using the multiresidue method (MRM)
in the Pesticide Analytical Manual, volume I (PAM, Vol. I) Section 302
and partially recovered (22-87% recovery) using Sections 303 and 304,
with the recovery varying depending upon the choice of Florisil system
used.

860.1380 Storage Stability

Residue Chemistry Chapter of the Prometryn RED, DP# 207139, 12/8/94, C.
Swartz

Storage stability data are available for fortified samples of celery,
cotton seed, fresh and dried parsley, pigeon peas, and sesame seed. 
Residues of prometryn and the impurities/metabolites GS-11354 and
GS-26831 were found to be stable in/on cotton seed and celery samples
stored frozen at -20°C for up to 37 months, in/on fresh and dried
parsley samples stored frozen for up to 21.7 months, and in/on sesame
seed stored frozen for up to 14 months.  Residues of prometryn per se
were found to be stable in pigeon peas stored at -12°C for up to 42
days.

Concurrent storage stability data were generated with the carrot,
celeriac, cilantro, okra, and parsley field trial studies.  Untreated
samples were fortified with prometryn, GS-11354, and GS-26831 at 0.5 ppm
for each analyte and stored frozen under conditions similar to those of
the field samples.  The data demonstrate that residues of prometryn,
GS-11354, and GS-26831 are relatively stable in/on fortified carrot
stored frozen for up to 18.5 months, celeriac tops stored frozen for up
to 8.5 months, fresh and dried cilantro stored frozen for up to 30.1 and
26.7 months, respectively, okra stored frozen for up to 9.9 months, and
parsley stored frozen for up to 5.9 months.  Recoveries were slightly
low (65-72%) for celeriac roots stored frozen for 8.7 months.

The storage durations and conditions of samples from the crop field
trials submitted to support this petition are presented in Table 4.

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

Matrix 	Storage Temperature (°C)	Actual Storage Duration	Interval of
Demonstrated Storage Stability

Carrot, root	-37 to -2	22-495 days

(0.7-16.3 months)	Residues of prometryn, GS-11354, and GS-26831 appear
to be stable in/on carrot stored frozen for up to 18.5 months;
concurrent storage stability data.

Celeriac, root	-38 to -3	74-218 days

(2.4-7.2 months)	Residues of prometryn, GS-11354, and GS-26831 appear
relatively stable in/on celeriac roots and tops stored frozen for up to
8.5 months; concurrent storage stability data.

Celeriac, top

79-226 days

(2.6-7.4 months)

	Cilantro, fresh	-38 to -3	330-936 days

(10.8-30.8 months)	Residues of prometryn, GS-11354, and GS-26831 appear
relatively stable in/on cilantro fresh and dried stored frozen for up to
30.1 and 26.7 months, respectively; concurrent storage stability data.

Cilantro, dried

331-904 days

(10.9-29.7 months)

	Okra	-38 to -6	57-300 days

(1.9-9.9 months)	Residues of prometryn, GS-11354, and GS-26831 appear to
be stable in/on okra stored frozen for up to 9.9 months; concurrent
storage stability data.

Parsley	-36 to -5	82-177 days

(2.7-5.8 months)	Residues of prometryn, GS-11354, and GS-26831 appear to
be stable in/on parsley stored frozen for up to 5.9 months; concurrent
storage stability data.

Conclusions:  The storage conditions and durations of samples from the
magnitude of the residue studies on carrot, celeriac, cilantro, okra,
and parsley are supported by adequate storage stability data.  These
data show that corrections for storage degradation of residues are not
required for the submitted studies.

Zero-day data were not provided with the concurrent storage stability
studies; IR-4 is reminded that storage stability studies should always
include a 0-day sampling interval to establish the residue levels
present at the time samples are placed into storage [see OPPTS
860.1380(d)(6)(i)].

860.1480 Meat, Milk, Poultry, and Eggs

Residue Chemistry Chapter of the Prometryn RED, DP# 207139, 12/8/94, C.
Swartz

The 1994 Residue Chemistry Chapter concluded that residues of prometryn
per se in meat and milk can be classified under Category 3 of 40 CFR
§180.6(a).  That is, there is no reasonable expectation of finite
residues in meat and milk.  No tolerances were required, and therefore,
livestock feeding studies were not needed.  In the current petition, the
only livestock feedstuff is carrot culls which may contribute up to 10%
in dairy cow diets only.  Pending submission of additional plant
metabolism and crop field trial data, HED tentatively concludes that the
Category 3 situation remains valid for this registration request. 
Because there are no established or proposed tolerances for prometryn
residues in livestock commodities, feeding studies are not required at
this time.

860.1500 Crop Field Trials

Carrot

DER Reference:   47548702.der.doc

A tolerance for carrot root is currently established at 0.1 ppm under 40
CFR §180.222(a) for  carrots without a U.S. registration, based on U.S.
and European data generated in 1963-1964.  These data reflect
application rates of 0.7-4.8 lb ai/A, with PHIs of 97-148 days (U.S.) or
41-183 days (Europe); the type of applications made was not specified. 
Residues of prometryn ranged from <0.04 to <0.1 ppm (except in one
France trial in which residues were <0.2 ppm).  These data were not
formally reviewed or submitted to EPA (Health Canada provided HED their
review, dated 6/18/65, of the residue data for carrots), but the request
was evaluated by the HED for establishment of a tolerance without U.S.
registration on carrot (PP#6E4691; DP#s 237148 & 224645, 1/20/98, W.
Wassell).

IR-4 is now proposing a tolerance and use on carrot in the U.S.  The new
carrot field trial data are summarized below.

Six carrot field trials were conducted in the U.S. in Zones 3 (FL), 6
(TX; 2 trials), and 10 (CA; 3 trials) during the 1996-1997 growing
seasons.  At each test location, the 4 lb/gal FlC formulation of
prometryn was applied as three broadcast applications at 1.93-2.01 lb
ai/A/application.  The first application was made preemergence (post
planting), the second application was made post-emergence, 38-57 days
later to carrots at the 2-3 leaf stage, and the third application was
made 21-80 days later to carrots at the 4-6 leaf stage, for a total
application rate of 5.86-6.02 lb ai/A (~1x the maximum proposed seasonal
rate).  All applications were made using ground equipment in 26-57 gal/A
(GPA) spray volumes with an adjuvant, except for the two TX trials which
did not include use of an adjuvant.  Mature carrots were harvested at
PHIs of 29-33 days; the tops were discarded, and only the roots were
retained.  An untreated plot was included at each trial site.

Samples of carrot root were analyzed for residues of prometryn and the
triazine impurities GS-11354 and GS-26831 using a GC/FPD/S method
modified from Method AG-559.  This method is adequate for data
collection based on acceptable method validation and concurrent method
recoveries.  The LLMV was 0.05 ppm for each analyte.

The results (see Table 5) indicate that following a preemergence and two
subsequent post-emergence broadcast applications of the 4 lb/gal FlC
formulation of prometryn for a total rate of 5.9-6.0 lb ai/A, residues
of prometryn were 0.059-0.440 ppm, and residues of GS-11354 and GS-26831
were each below the method LLMV (<0.05 ppm) in/on carrot harvested at
PHIs of 29-33 days.  The petitioner noted that residues in one TX trial,
bearing the highest residues (0.403 and 0.440 ppm), were likely due to
adhering soil; re-analysis of these samples following removal of
adhering soil (method not described) resulted in prometryn residues of
0.140 and 0.173 ppm.  Excluding “soil-contaminated samples” and
including the re-analyzed samples demonstrates residues of prometryn
ranging 0.059 to 0.282 ppm in/on carrot root.

No residue decline data were provided.

Table 5.   Summary of Residue Data from Carrot Field Trials with
Prometryn.

Commodity	Total Applic. Rate

(lb ai/A)	PHI (days)	Residue Levels of Prometryn (ppm)1

	n	Min.	Max.	HAFT2	Mean	Std. Dev.

Proposed Use Pattern = Maximum Seasonal Rate of 6.0 lb ai/A with a
30-Day PHI

Carrot, root	5.9-6.0	29-33	12	0.059	0.282

[0.440]	0.248

[0.422]	0.162

[0.206]	0.062

[0.118]

1  Only the residue of concern (prometryn) is summarized.  Bracketed
values include the “soil contaminated” residues from the TX*34
trial.

2  HAFT = highest-average field trial.

Conclusions:  The carrot field trial data support the proposed use
pattern.  However, the number and location of field trials are
inadequate to satisfy data requirements because only six field trials
were conducted, whereas the guideline requires 8 trials to establish an
individual tolerance on carrot, and no trials were conducted in Zones 5
(Zone 6 trials were not conducted in a location bordering Zone 5) or 11.

Although geographic representation is inadequate, HED concludes that the
available data are sufficient to support conditional registration of
prometryn on carrot because trials were conducted in zones representing
78% of carrot production in the U.S., and there is not a great deal of
variability in the residue values across the trial sites.  The results
indicate that following a combination of preemergence and postemergence
broadcast applications of the 4 lb/gal FlC formulation at ~1x the
proposed seasonal rate, residues of prometryn were 0.059-0.282 ppm in/on
carrots harvested at PHIs of 29-33 days (excluding “contaminated
residues”).  HED notes that the lowest residue values were observed in
one trial in which a surfactant was not used.

Three additional carrot trials are required in Zones 5, 10, and 11
reflecting application according to the maximum proposed use pattern,
including use of a surfactant; one of the trials should include residue
decline data.  Fulfillment of this data gap may be considered a
condition of registration.

The available data will tentatively support a tolerance for prometryn
per se in/on carrot roots at 0.45 ppm; the tolerance calculation is
presented in Appendix I.  

Celeriac

DER Reference:   47548704.der.doc

Three celeriac field trials were conducted in the U.S. in Zone 10 (CA)
during the 1999, 2001 and 2003 growing seasons.  At each test location,
the 4 lb/gal FlC formulation of prometryn was applied as a single
broadcast application to celeriac at the 6- to 8-leaf growth stage, at
3.87-4.0 lb ai/A (~1.0x the maximum proposed seasonal rate). 
Applications were made using ground equipment in 30-35 GPA spray volumes
without an adjuvant.  Mature celeriac (roots and tops) was harvested
59-61 days after application.  An untreated plot was included at each
trial site.

Samples of celeriac root and tops were analyzed for residues of
prometryn and the triazine impurities GS-11354 and GS-26831 using a
GC/FPD/S method modified from Method AG-559.  This method is adequate
for data collection based on acceptable method validation and concurrent
method recoveries.  The LLMV was 0.05 ppm for each analyte.

The results (see Table 6 below) indicate that following a single foliar
broadcast application of the 4 lb/gal FlC formulation of prometryn at
3.9-4.0 lb ai/A, residues of prometryn were below the LLMV (<0.05 ppm)
to 0.05 ppm in/on roots, and <0.05-0.178 ppm in/on tops harvested at
PHIs of  59-61 days; GS-11354 and GS-26831 were each below the method
LLMV (<0.05 ppm) in/on all root and top samples.  [It is noted that the
petitioner stated that all residues were nonquantifiable in/on all root
and top samples, but the raw data showed quantifiable residues of
prometryn (at the LLMV) in/on one root sample from the 2001 trial, and
quantifiable residues of prometryn in/on both top samples from the 2003
trial.  The petitioner did not address the large difference in the
residues of prometryn observed in top samples from one trial compared to
the nonquantifiable residues in the other two trials.] 

Residue decline data were not provided and none are required because
only three trials are needed to support uses on celeriac
(860.1500(2)(iv)).

Table 6.   Summary of Residue Data from Celeriac Field Trials with
Prometryn. 

Commodity	Total Applic. Rate

(lb ai/A)	PHI (days)	Residue Levels of Prometryn (ppm)1

	N	Min.	Max.	HAFT2	Mean	Std. Dev.

Proposed Use Pattern = Maximum Seasonal Rate of 4.0 lb ai/A with a
60-Day PHI

Celeriac, root	3.9-4.0	59-61	6	<0.05	0.0513	0.051	0.050	0.001

Celeriac, top

	6	<0.05	0.178	0.144	0.081	0.053

1  Only the residue of concern (prometryn) is summarized.  For
statistical calculations, the LLMV (0.05 ppm) was used for values
reported as less than the LLMV.

2  HAFT = highest-average field trial.

Conclusions:  Provided the use directions are revised as specified under
860.1200, the celeriac field trial data are adequate and support the
proposed use pattern.  Geographic representation of data is adequate. 
The results indicate that following a single foliar broadcast
application of the 4 lb/gal FlC formulation of prometryn at ~1x the
proposed seasonal rate, residues of prometryn were below the LLMV (<0.05
ppm) to 0.05 ppm in/on roots, and <0.05-0.178 ppm in/on tops at PHIs of
59-61 days.  These data will support the proposed tolerance for
prometryn per se at 0.05 ppm in/on celeriac root and a tolerance for
residues at 0.20 ppm in/on celeriac tops.  

Cilantro

DER Reference:   47548705.der.doc

Five cilantro field trials were conducted in the U.S. in Zone 10 (CA)
during the 2004 and 2006 growing seasons.  At each test location, the 4
lb/gal FlC formulation of prometryn was applied as a single broadcast
preemergence application (postplanting) to the soil, at 1.6 lb ai/A (1x
the maximum proposed seasonal rate).  Applications were made using
ground equipment in 18-26 GPA spray volumes without an adjuvant.  Fresh
cilantro was harvested at PHIs of 30-33 days.  At three sites,
additional cilantro samples were collected at PHIs of 33-36 days, and
the collected samples were dried according to commercial practices.  An
untreated plot was included at each trial site.

Samples of cilantro were analyzed for residues of prometryn and the
triazine impurities GS-11354 and GS-26831 using an HPLC/MS/MS method
modified from Method AG-559.  This method is, overall, adequate for data
collection based on method validation and concurrent method recoveries. 
The LLMV was 0.02 ppm for each analyte in fresh cilantro and 0.05 ppm
for each analyte in dried cilantro.

The results (see Table 7) indicate that following a single broadcast
preemergence application (postplanting) to the soil, at 1.6 lb ai/A,
residues of prometryn were below the LLMV (<0.02 ppm) to 2.3 ppm in/on
fresh cilantro harvested at PHIs of  30-33 days, and 0.094-8.8 ppm in/on
dried cilantro harvested at PHIs of 33-36 days.  Residues of GS-11354
were <0.02-0.24 ppm and <0.05-0.87 ppm in fresh and dried cilantro,
respectively, and residues of GS-26831 were below the method LLMV (<0.02
or <0.05 ppm, respectively) in/on all fresh and dried cilantro samples.

Residue decline data were not provided, and none are required because
only three trials are needed to support uses on cilantro as a minor crop
(860.1500(2)(iv)) and because application is made preemergence. 

Table 7.   Summary of Residue Data from Cilantro Field Trials with
Prometryn.

Commodity	Total Applic. Rate

(lb ai/A)	PHI (days)	Prometryn Residue Levels (ppm)1

	N	Min.	Max.	HAFT2	Mean

	Std. Dev.

Proposed Use Pattern = Maximum Seasonal Rate of 1.6 lb ai/A with a
30-Day PHI

Cilantro, fresh	1.6-1.7	30-33	10	<0.02	2.3	2.1	0.60	0.86

Cilantro, dried

33-36	3	0.094	8.8	8.8	3.0	5.0

1  Only the residue of concern (prometryn) is summarized.  For
statistical calculations, the LLMV (0.02 ppm for fresh cilantro) was
used for values reported as less than the LLMV.

2  HAFT = highest-average field trial.

Conclusions:  Provided the use directions are revised as specified under
860.1200, the cilantro field trial data are adequate and support the
proposed use pattern.  Geographic representation of the data is
adequate.  The results are quite variable and indicate that following a
single broadcast preemergence application (post planting) of the 4
lb/gal FlC formulation to the soil, at 1.6-1.7 lb ai/A, residues of
prometryn were below the LLMV (<0.02 ppm) to 2.3 ppm in/on fresh
cilantro harvested at PHIs of 30-33 days.  These data will support a
tolerance for cilantro leaves of 3.5 ppm; see Appendix I for calculation
of recommended tolerance using the Agency’s tolerance spreadsheet.  

Okra

DER Reference:   47548701.der.doc

Five okra field trials were conducted in the U.S. in Zones 2 (NC, TN; 2
trials), 3 (FL; 1 trial), and 6 (TX; 2 trials) during the 2003 growing
season.  At each test location, the 4 lb/gal FlC formulation of
prometryn was applied as a preemergence treatment (broadcast to the soil
surface) at 0.74-0.81 lb ai/A, followed 32-67 days later by a single
directed postemergence treatment (12-20” swath or band on each side of
the rows) at 0.74-0.75 lb ai/A, for a total rate of 1.5-1.6 lb ai/A (1x
the maximum proposed seasonal rate).  Plants had 7-9 true leaves present
at the time of the postemergence application.  Mature okra pods were
harvested at PHIs of 12-39 days.  An additional plot at three trial
sites received only a preemergence treatment (broadcast to the soil
surface) at 1.5-1.7 lb ai/A (1x); mature okra pods were harvested at
PHIs of 49-79 days.  At two trial sites, a third plot received a
preemergence application (broadcast to the soil surface) followed 40-58
days later by a single postemergence (directed application) at 1.50-1.53
lb ai/A/application, for a total rate of 3.0 lb ai/A (2x).  Plants had
7-9 true leaves present at the time of the postemergence application. 
Mature okra pods were harvested at PHIs of 15 or 21 days.  All
applications were made using ground equipment in 23-35 GPA spray volumes
without an adjuvant.  An untreated plot was included at each trial site.

Samples of okra were analyzed for residues of prometryn and the triazine
impurities GS-11354 and GS-26831 using a GC/FPD/S method modified from
Method AG-559.  This method is adequate for data collection based on
acceptable method validation and concurrent method recoveries.  The LLMV
was 0.05 ppm for each analyte.

The results (see Table 8) indicate that following a preemergence and
subsequent postemergence application of the 4 lb/gal FlC formulation of
prometryn for a total rate of 1.5-1.6 or 3.0 lb ai/A, residues of
prometryn, GS-11354, and GS-26831 were each below the method LLMV (<0.05
ppm) in/on okra pods harvested at PHIs of 12-39 days.  In okra treated
only with a single preemergence application at 1.5-1.7 lb ai/A, residues
were also <0.05 ppm for each analyte.

Residue decline data were not provided but residues were nonquantifiable
in/on all okra samples harvested at various PHIs.



Table 8.   Summary of Residue Data from Okra Field Trials with
Prometryn. 

Commodity	Total Applic. Rate

(lb ai/A)	PHI (days)	Residue Levels of Prometryn (ppm) 1

	N	Min.	Max.	HAFT2	Mean

	Std. Dev.3

Proposed Use Pattern = Maximum Seasonal Rate of 1.5 lb ai/A with a
14-Day PHI

Okra, pods	1.48-1.56

(pre+post)	12-39	10	<0.05	<0.05	<0.05	0.05	NA

	1.50-1.67

(pre only)	49-79	6	<0.05	<0.05	<0.05	0.05	NA

	3.01-3.04

(pre+post)	15-21	4	<0.05	<0.05	<0.05	0.05	NA

1  Only the residue of concern (prometryn) is summarized.  For
statistical calculations, the LLMV (0.05 ppm) was used for values
reported as less than the LLMV.

2  HAFT = highest-average field trial.

3  Standard deviation is not applicable (NA) when all residues are
nonquantifiable.

Conclusions:  Provided the use directions for Caparol® 4L Herbicide are
revised as specified under 860.1200, the okra field trial data are
adequate and support the proposed use pattern.  The results indicate
that residues of prometryn were each below the method LLMV (<0.05 ppm)
in/on okra pods harvested at PHIs of 12-79 days after the 4 lb/gal FlC
formulation was applied as preemergence treatment at 1x or a combination
of preemergence and postemergence treatments at ~1x or 2x.  These data
will support the proposed tolerance for residues of prometryn per se of
0.05 ppm in/on okra.

Parsley

DER Reference:   47548703.der.doc

A tolerance for parsley is currently established at 0.1 ppm under 40 CFR
§180.222(c) for regional use of prometryn on parsley.  Residue data in
support of the prometryn use in CA were reviewed under PP#6E3460 (DP#
173612, 8/19/92, R. Cook).  Residues of prometryn were <0.05 ppm in/on
parsley after a preemergence application at 2 or 4 lb ai/A.

Additional residue data were summarized for use on parsley in FL (ID#
FL970011; DP# 243274, 5/14/98, W. Wassell); these data reflected three
applications at 0.5 lb ai/A with a 30-day PHI after the second and third
application, and residues of prometryn were <0.05-0.07 ppm in/on parsley
receiving two applications.  As the bulk of residue data reflect
preemergence application, these data do not support the uses proposed
under the current action.

Two parsley field trials were conducted in the U.S. in Zones 2 (NJ) and
6 (TX) during the 1997 growing season.  At each test location, the 4
lb/gal FlC formulation of prometryn was applied as three broadcast
applications at ~0.50 lb ai/A/application.  The first application was
made preemergence (post planting) at one trial and early postemergence,
at the cotyledon/1-leaf stage, at the other trial.  At both trials, the
second application was made postemergence, 42-68 days later, to parsley
at the vegetative stage and prior to the first harvest; and a third
application was made to the stubble remaining after the first harvest or
immediately after the regrowth had started.  The total application rates
were 1.0 lb ai/A for the first harvest of parsley which had received two
applications, 0.5 lb ai/A for the second harvest of parsley which
received one application, and a 1.5 lb ai/A seasonal rate which includes
all three applications (1x the maximum proposed seasonal rate).  All
applications were made using ground equipment in 26-44 GPA spray volumes
without an adjuvant.  First-growth parsley was harvested 30 days after
the second application, and the parsley regrowth was harvested 31-32
days after the third application.  An untreated plot was included at
each trial site.

Samples of parsley were analyzed for residues of prometryn and the
triazine impurities GS-11354 and GS-26831 using a GC/FPD/S method
similar to the available enforcement method (AG-559) for plants.  This
method is adequate for data collection based on acceptable method
validation and concurrent method recoveries.  The LLMV was 0.05 ppm for
each analyte.

The results (see Table 9) indicate that following a preemergence (or
early postemergence) and subsequent postemergence broadcast applications
of the 4 lb/gal FlC formulation of prometryn for a total rate of 1.0 lb
ai/A, residues of prometryn were 0.216-0.339 ppm, and residues of
GS-11354 and GS-26831 were each below the method LLMV (<0.05 ppm) in/on
fresh parsley harvested 30 days after the second application.  In
second-cutting parsley, harvested 31-32 days following a single
broadcast application made after harvest of first-cutting parsley at 0.5
lb ai/A, residues of prometryn were <0.05 ppm from one trial and
0.187-0.338 ppm in the other; residues of GS-11354 and GS-26831 were
each <0.05 ppm in both trial samples.  Overall, prometryn residues
ranged from below the LOQ (<0.05 ppm) to 0.339 ppm in/on all parsley
samples.  The petitioner noted that in the second-cutting parsley from
the NJ trial, residues of prometryn were nonquantifiable, which may be
due to the application being made to the remaining stubble after the
first harvest and before regrowth had actually started, and also rain
which was received within 6 hours of that application.

Residue decline data were not provided, and none are required for the
proposed use on parsley.

Table 9.  Summary of Residue Data from Parsley Field Trials with
Prometryn.

Commodity	Total Applic. Rate

 (lb ai/A)	PHI (days)	Residue Levels of Prometryn (ppm)1

	n	Min.	Max.	HAFT2	Mean	Std. Dev.

Proposed Use Pattern = Maximum Seasonal Rate of 1.5 lb ai/A (or 2.0 lb
Per Year in CA)

with a 30-Day PHI

Parsley	1.0 (1st cut)	30	4	0.216	0.339	0.331	0.284	0.057

	0.50 (2nd cut)	31-32	4	<0.05	0.338	0.263	0.156	0.137

	1.5 (both cuts)	30-32	8	<0.05	0.339	0.263	0.220	0.119

1  For statistical calculations, the LLMV (0.05 ppm) was used for values
reported as less than the LLMV in Table C.3. 

Only the residue of concern (prometryn) is summarized.

2  HAFT = highest-average field trial.

Conclusions:  Provided the use directions are revised as specified under
860.1200, the parsley field trial data support the proposed use pattern.
 However, the number and location of field trials are inadequate to
satisfy data requirements because only two trials were conducted, and
three are required to establish a tolerance on parsley.

Although the number of field trials is inadequate, RAB1 concludes that
the available data are sufficient to support conditional registration of
prometryn on parsley because the results were consistent for first
cuttings across the trial sites, and the first cutting results were
consistent with those for the second cutting obtained when prometryn was
applied after regrowth had started.  Residues of prometryn were
0.216-0.339 ppm in/on parsley harvested 30 days following application at
1x the maximum proposed seasonal rate of 1.0 lb ai/A.  Residues of
prometryn were <0.05-0.339 ppm in/on parsley harvested 30-32 days
following application at 1x the maximum proposed yearly rate of 1.5 lb
ai/A.  

The available data will support a tolerance for residues of prometryn
in/on parsley at 0.60 ppm; see Appendix I for calculation of tolerance
using the Agency’s tolerance spreadsheet.  

860.1520 Processed Food and Feed

DER Reference:   47548705.der.doc

Parsley and cilantro are herb crops for which the dried crop is the
processed commodity.  Processing data for dried cilantro were submitted
in conjunction with the field trials for fresh cilantro (see Section
860.1500).  Residues of prometryn concentrated 3.9-4.7x in dried
cilantro processed from fresh cilantro which had been treated with a
preemergence application of prometryn to the soil, at 1.6 lb ai/A.  The
average processing factor in dried cilantro was 4.3x; individual trial
data (and processing factors) are presented in Table 10.

Table 10.   Processing Factors for Prometryn in Cilantro.

RAC	Processed Commodity	Total Rate

(lb ai/A) 	PHI

(days)	Prometryn Residues1

(ppm)	Processing Factor

Cilantro

(CA153)	Fresh (RAC)	1.55	33	1.9, 2.3 (2.1)	--

	Dried

	8.8	4.2x

Cilantro

(CA06)	Fresh (RAC)	1.65	33	0.035, 0.037 (0.036)	--

	Dried

36	0.14	3.9x

Cilantro

(CA143)	Fresh (RAC)	1.58	33	<0.02, <0.02 (<0.02)	--

	Dried

	0.094	4.7x

1 The average residue in the raw agricultural commodity (RAC), used for
calculating the processing factor, is reported in parentheses.

Conclusions:  Adequate processing data are available for cilantro; these
data will be translated to parsley.  Residues of prometryn concentrated
(processing factors of 3.9-4.7x) in dried cilantro processed from fresh
cilantro bearing detectable residues.  Based on the highest-average
field trial (HAFT) residues of 2.1 ppm in fresh cilantro and an average
processing factor of 4.3x, the expected residues in cilantro, dried
leaves would be 9.03 ppm.  The available data will support a tolerance
for residues at 9.0 ppm for coriander, dried leaves.  Based on the HAFT
residues of 0.331 ppm in fresh parsley and an average processing factor
of 4.3x, the expected residues in parsley, dried leaves would be 1.5
ppm.  The available data will support a tolerance for residues at 1.5
ppm for parsley, dried leaves.  As the petitioner did not propose a
tolerance for residues in/on parsley, dried leaves, a revised Section F
is required. 

  SEQ CHAPTER \h \r 1 860.1650 Submittal of Analytical Reference
Standards

Analytical standards for prometryn are currently available [expiration
1/1/2010 (Syngenta) and 5/1/2011 (MANA)] in the EPA National Pesticide
Standards Repository (personal communication with Dallas Wright, ACB,
12/18/08).  Analytical reference standards of prometryn must be
replenished as requested by the Repository.  The reference standards
should be sent to the Analytical Chemistry Lab, which is located at Fort
Meade, to the attention of either Theresa Cole at the following address:

	USEPA

	National Pesticide Standards Repository/Analytical Chemistry Branch/OPP

	701 Mapes Road

	Fort George G. Meade, MD  20755-5350

(Note that the mail will be returned if the extended zip code is not
used.)

860.1850 Confined Accumulation in Rotational Crops

Residue Chemistry Chapter of the Prometryn RED, DP# 207139, 12/8/94, C.
Swartz

The nature of the residue in rotational crops is adequately understood. 
The metabolism of prometryn in rotational crops is similar to that of
the primary crops and involves dealkylation, oxidation, hydroxylation,
deamination, and conjugation.

Ring-labeled [14C]prometryn was applied to test sites containing sandy
loam soil in MS and CA.  At the MS site, prometryn was applied at 2.8 lb
ai/A at the time of planting to a primary crop of cotton.  Further
applications were made when the plants were 3-6" tall (0.65 lb ai/A) and
12-18" tall (1.6 lb ai/A) for a total application rate of 5.0 lb ai/A. 
At the CA site, a single application of prometryn was made at 3.2 lb
ai/A when the primary crop, celery, was immature.  After harvesting the
primary crop, the rotational crops were planted:  lettuce was planted
111 and 229 (MS) and 193 (CA) days after the final prometryn treatment
(DAT), wheat was planted 111 (MS) and 350 DAT (CA), soybeans were
planted 193 (CA) and 328 DAT (MS), and table beets were planted 193 (CA)
and 249 DAT (MS).

The total radioactive residues (TRR) in all RACs from all PBIs at both
sites exceeded 0.01 ppm.  The TRR values ranged 0.030-0.447 ppm.  The
following metabolites were identified in the rotational crops: 
prometryn, GS-11957, GS-17794, MCO-III-25, MCO-IV-34, GS-11526 and its
side chain alcohol, along with unidentified acetyl and sugar conjugates
of triazines.  Although 14C-residues were not quantified, greater than
50% of the TRR appeared to consist of triazine-containing metabolites. 
Based on these data, the registrant conducted limited field rotational
crop studies.

860.1900 Field Accumulation in Rotational Crops

Residue Chemistry Chapter of the Prometryn RED, DP# 207139, 12/8/94, C.
Swartz

DP#s 315763 & 357098, review pending

No new field accumulation data in rotational crops were submitted with
this petition.  Previously reviewed studies include a limited rotational
crop study (DP#s D191118 & 191119, 9/3/93, G. Kramer) reflecting
application to a primary crop or bare soil at 5-12 lb ai/A, with
rotational crops planted at PBIs of 3-4 and 7-9 months, and an extensive
rotational crop study (DP# 207717, 12/5/94, C. Swartz) on small grains
reflecting application at 5-6 lb ai/A and a 3- to 6-month PBI.  Based on
these studies, HED previously recommended a rotational crop restriction
of 8 months for root crops, required additional rotational crop data for
leafy vegetables, and recommended a 3-month PBI with establishment of
rotational crop tolerances for small grain forage, hay, and straw.  The
requested tolerances have not been established.

Additional data reflecting application to a primary crop or bare soil at
3.2 lb ai/A (~0.5x maximum proposed seasonal rate for carrot) and PBIs
of 5 and 9 months have recently been submitted (DP#s 315763 & 357098;
review pending).  These data indicate that residues of prometryn are
nonquantifiable in leafy vegetables at both PBIs, and in root crops and
small grains at the 9-month PBI.

Conclusions:  Based on review of available field rotational crop data,
HED has determined that, pending resolution of deficiencies identified
under DP#s 315763 & 357098 concerning the soil characteristics and
sample harvest and handling procedures in the most recent study, the
data will support the following minimum plantback restrictions for crops
not listed on prometryn labels:  (1) Following maximum application to
any primary crop at up to 3.2 lb ai/A:  a 5-month PBI for leafy
vegetables, an 8-month PBI for root crops, and a 9-month PBI for small
grains and all other crops.  (2) Following application at rates higher
than 3.2 lb ai/A and up to 6.0 lb ai/A:  an 8-month PBI for root crops;
rotation to all other crops is prohibited.

860.1550 Proposed Tolerances

HED has determined that the residue of concern for tolerance enforcement
in primary and rotated crops is prometryn per se.  The tolerance
expression proposed in this petition is appropriate.

The proposed tolerances and the Agency’s recommendations are presented
in Table 11. 

Although three additional trials are required for carrots, HED
tentatively recommends a tolerance for residues at 0.45 ppm in/on carrot
roots concomitant with the removal of the established tolerance without
U.S. registration at 0.1 ppm for the same RAC.  The Agency’s tolerance
spreadsheet (Guidance for Setting Pesticide Tolerances Based on Field
Trial Data SOP; see Appendix I) was used to determine an appropriate
tolerance level.

The submitted data for celeriac are adequate and will support the
proposed tolerance of 0.05 ppm for celeriac root and a tolerance of 0.20
ppm for celeriac tops.  The Agency’s tolerance spreadsheet was not
used to calculate tolerance levels because >60% of residues values for
both roots and tops were below the LOQ.

The submitted data for cilantro are adequate and will support a
tolerance for residues at 3.5 ppm in/on cilantro leaves.  The tolerance
was determined using the Agency’s tolerance spreadsheet (Appendix 1);
because LLMV values comprised >10% and <60% of the total number of
residue values, maximum-likelihood estimation (MLE) procedures were
needed to impute censored values for cilantro.

The submitted data for okra are adequate and will support the proposed
tolerance for residues of 0.05 ppm in/on okra.  The Agency’s tolerance
spreadsheet was not used to calculate tolerance levels because all
residues values were below the LOQ.

HED recommends a tolerance of 0.60 ppm for parsley leaves concomitant
with the removal of the established tolerance for residues with regional
restriction for the same commodity.  The Agency’s tolerance
spreadsheet (see Appendix I) was used to determine an appropriate RAC
tolerance level; because LLMV values comprised >10% and <60% of the
total number of residue values, MLE procedures were needed to impute
censored values for parsley, leaves.

Adequate data are available for cilantro as an herb crop.  The data
indicate that residues may concentrate (4.3x) in dried cilantro.  The
data for fresh and dried cilantro indicate that the proposed tolerance
of 15 ppm for cilantro (dry) is too high; a tolerance for residues at
9.0 ppm is recommended.

Processing data for cilantro will be translated to parsley.  The data
indicate that a tolerances for prometryn at 1.5 ppm in/on parsley, dried
leaves.

The proposed tolerances should be revised to reflect the recommended
tolerance levels and correct commodity definitions as specified in Table
11.

There are currently no established Codex MRLs for prometryn.  No
Canadian MRLs have been established for prometryn, although prometryn is
registered for use in Canada on carrots, celery, leeks, and peas.  These
uses presumably fall under the PMRA General MRL of 0.1 mg/kg. 
[Regulation B.15.002(1) of the Canadian Food and Drugs Regulations (FDR)
establishes 0.1 ppm as the General Maximum Residue Limit.  This
regulation states that a food is adulterated if it contains residues of
a pesticide at a level greater than 0.1 ppm unless a specific MRL has
been established in Table II, Division 15 of the FDR.  PMRA is in the
process of revoking this general MRL and establishing individual
tolerances.]  Mexican MRLs have been established for residues of
prometryn in/on corn, cotton, and pea, at 0.25 ppm, and celery at 0.5
ppm.

Table 11.  Tolerance Summary for Prometryn.

Commodity	Proposed Tolerance (ppm)	Recommended Tolerance (ppm)	Comments;
Correct Commodity Definition

Carrot	0.7	0.45	The recommended tolerance is tentative as three
additional carrot trials are required.  Concurrent with granting a
national registration, the established import tolerance at 0.1 ppm
should be removed.

Carrot, roots

Celeriac, Roots	0.05	0.05	Celeriac, roots

Celeriac, Tops	0.05	0.20	Celeriac, tops

Cilantro (Fresh)	4.0	3.5	Cilantro, leaves

Cilantro (Dry)	15	9.0	Coriander, dried leaves

Okra	0.05	0.05

	Parsley, leaves	0.70	0.60	Concurrent with granting a national
registration, the established tolerance with regional exemption for the
same RAC should be removed.

Parsley, dried leaves	--	1.5	Parsley,  dried leaves

References

DP#:		None; RCB No. 2907

Subject:	Prometryn - EPA Registration No. 100-542 Ciba-Geigy’s
Response to the Product Chemistry Chapter Dated September 25, 1987.

From: 		G. Makhijani

To:		R. Taylor/J. Miller and W. Boodee

Dated:		12/4/87

MRID(s): 	4035601, 40356002

DP#:		173612

Subject:	PP6E3460.  Prometryn on Parsley.  IR-4 Response of 12/12/91.

From: 		R. Cook

To:		H. Jamerson

Dated:		8/19/92

MRID(s): 	42140201

DP#s:		191119 & 191118

Subject:	ID# 080805.  Review of rotational crop studies of prometryn. 
Case 819250.  CBTS# 11852.

From: 		G. Kramer

To:		L. Propst

Dated:		9/3/93

MRID(s): 	42081601 and 41901202

DP#s:		196116 & 196123

Subject:	Prometryn.  Agan 12/7/92 & 8/4/93 Responses [Series 61, 62-2
[CSF], 63-9, -11, -16, -17, & -20 data for EPA Reg. 46386-2] to 5/24/91
RS Update & 3/2/93 K. Dockter Review; CBRS 11098.  Rereg. Case 0467. 
CBRSs 12712 & 12713.  

From: 		K. Dockter

To:		M. Fiol

Dated:		4/25/94

MRID(s): 	42579101-04, 42842001 & 42872801

DP#:		207717

Subject:	Prometryn.  List A Reregistration Case No. 0467/Chemical ID No.
080805.  Ciba-Geigy Submission of Data to Satisfy Guideline Requirements
165-2, Field Rotational Crop and 171-4(e), Storage Stability; ADecision
on Magnitude of the Residue in Livestock, 171-4(j).  CBRS No. 14412.  

From: 		C. Swartz

To:		L. Propst

Dated:		12/5/94

MRID(s): 	43370404, 43370405

DP#:		207139

Subject:	Prometryn.  List A Reregistration Case No. 0467/Chemical ID No.
080805.  Product and Residue Chemistry Considerations to be Included in
the HED Chapter of the Reregistration Eligibility Decision Document. 
CBRS No. 14299.  

From: 		C. Swartz

To:		D. Edwards

Dated:		12/8/94

MRID(s): 	None

DP#s:		237148 & 224645

Subject:	PP#6E4691.  Prometryn in or on Carrots.  Tolerance with no U.S.
Registration.  U.S. Harmonization of Pesticide Tolerances with Canada.  

From: 		W. Wassell

To:		J. Tompkins/T. Colvin-Snyder

Dated:		01/20/98

MRID(s): 	None

DP#:		243274

Subject:	ID# FL970011, Prometryn in/on dill and parsley.  Request for
24(c) Registration by the State of Florida.  

From: 		W. Wassell

To:		J. Tompkins/L. Jones

Dated:		5/14/98

MRID(s): 	None

DP#:		315763 & 357098

Subject:	Prometryn.  Registration Request to Add New Use on Leaf
Petioles (Crop Subgroup 4B).  Summary of Analytical Chemistry and
Residue Data.  

From: 		

To:		

Dated:		Review Pending

MRID(s): 	44556802, 44556803, 45190601

  SEQ CHAPTER \h \r 1 Attachments:

International Residue Limit Status Sheet 

Appendix I - Tolerance Assessment Calculations

RDI: RAB1:  05/06/2009

Petition Number:  PP#8E7434

DP Number:  357094

PC Code:  080805

WDWassell:S10316:Potomac Yard:703-305-6135:7509P:RAB1

Template Version September 2005



INTERNATIONAL RESIDUE LIMIT STATUS

Chemical Name: 
N,N'-bis(1-methylethyl)-6-(methylthio)-1,3,5-triazine-2,4-diamine	Common
Name:

Prometryn

	X Proposed tolerance

( Reevaluated tolerance

( Other	Date:  12/17/08

Codex Status (Maximum Residue Limits)	U. S. Tolerances

X No Codex proposal step 6 or above

( No Codex proposal step 6 or above for the crops requested	Petition
Number:  PP#8E7434

DP#:  357094

Other Identifier:  Decision# 400395  

Residue definition (step 8/CXL):   N/A	Reviewer/Branch:  W. Wassell/RAB1

	Residue definition:  prometryn
(2,4-bis(isopropylamino-6-methylthio-s-triazine)

Crop (s)	MRL (mg/kg)	Crop(s) 	Tolerance (ppm)

Carrot	0.7

Celeriac, roots	0.05

Celeriac, tops	0.05

Cilantro (fresh)	4.0

Cilantro (dry)	15

Okra	0.05

Parsley, leaves	0.7

Limits for Canada	Limits for Mexico

X No Limits

( No Limits for the crops requested	X No Limits

( No Limits for the crops requested

Residue definition:  N/A

	Residue definition:  N/A

Crop(s)	MRL (mg/kg)	Crop(s)	MRL (mg/kg)

	Notes/Special Instructions: S.Funk, 12/28/2008.

Appendix I

Tolerance Assessment Calculations

For each of the crops listed below, the Guidance for Setting Pesticide
Tolerances Based on Field Trial Data (SOP), along with the tolerance
spreadsheet (January 2008 version), was used for calculating recommended
tolerances.  

Carrot

The dataset used to establish a tolerance for prometryn on carrot
consisted of field trial data representing application rates of 5.9-6.0
lb ai/A (1 preemergence and 2 postemergence applications at ~2 lb
ai/A/application) with a 29- to 33-day PHI.  The field trial application
rates and PHIs are within 25% of the maximum label application rate and
minimum label PHI, respectively.  The residue values that were entered
into the tolerance spreadsheet are provided in Table I-1.

All field trial sample results for prometryn in/on carrot roots were
above the LLMV (LLMV = 0.05 ppm).  The carrot dataset was small (12
samples).  Visual inspection of the lognormal probability plot (Figure
I-1) and the results from the approximate Shapiro-Francia test statistic
(Figure I-2) indicated that the carrot dataset was reasonably lognormal.

Because the field trial data for prometryn on carrot represent a small
dataset and are reasonably lognormal, the upper bound estimate of the
95th percentile based on the median residue value was compared to the
minimum of the 95% UCL on the 95th percentile and the point estimate of
the 99th percentile, and the minimum value was selected as the tolerance
value.  The recommended tolerance for residues is 0.45 ppm in/on carrot
roots. 

Table I-1.	Residue data used to calculate tolerance for residues of
prometryn on carrot.

Regulator:	EPA

Chemical:	Prometryn

Crop:	Carrot, root

PHI:	29-33 days

App. Rate:	5.9-6.0 lb ai/A

Submitter:	IR-4

MRID Citation:	MRID 47548702

	Residues of Prometryn (ppm)

	0.123

	0.148

	0.159

	0.188

	0.173

	0.213

	0.214

	0.282

	0.140

	0.173

	0.059

	0.071

Figure I-1.  Lognormal probability plot of prometryn field trial data
for carrot.

Figure I-2.  Tolerance spreadsheet summary of prometryn field trial data
for carrot.

Cilantro

The dataset used to establish a tolerance for prometryn on cilantro
consisted of field trial data representing application rates of 1.6 lb
ai/A (1 preemergence application) with a 30- to 33-day PHI.  The field
trial application rates and PHIs are within 25% of the maximum label
application rate and minimum label PHI, respectively.  The residue
values that were entered into the tolerance spreadsheet are provided in
Table I-2.

Only 6 out of 10 field trial sample results for prometryn in/on cilantro
were above the LLMV (LLMV = 0.02 ppm), therefore, MLE procedures were
needed to impute censored values for cilantro.  The cilantro dataset was
small (10 samples).  Visual inspection of the lognormal probability plot
(Figures I-3 and I-5) and the results from the approximate
Shapiro-Francia test statistic (Figures I-4 and I-6) indicated that the
cilantro dataset was reasonably lognormal.  

Because the field trial data for prometryn on cilantro represent a small
dataset and appear to be reasonably lognormal, if the upper bound
estimate of the 95th percentile based on the median residue value is
compared to the minimum of the 95% UCL on the 95th percentile and the
point estimate of the 99th percentile, the recommended tolerance for
cilantro leaves would be 0.25 ppm.  This value is much lower than the
highest observed residues in cilantro leaves.  

Based on examination of the residue values, HED believes that the four
values generated by the MLE procedures may have influenced the apparent
lognormality of the dataset.  In consideration of the variability of the
residues in cilantro, the upper bound on the 89th percentile
(distribution-free method) yields a more reasonable tolerance value;
thus, a tolerance of 3.5 ppm is recommended for cilantro leaves. 

Table I-2.	Residue data used to calculate tolerance for residues of
prometryn on cilantro.

Regulator:	EPA

Chemical:	Prometryn

Crop:	Cilantro, fresh (MLE)

PHI:	30-33 days

App. Rate:	1.6-1.7 lb ai/A

Submitter:	IR-4

MRID Citation:	MRID 47548705

	Residues of Prometryn (ppm)

	0.001

	0.002

	1.900

	2.300

	0.035

	0.037

	0.840

	0.850

	0.005

	0.011

Figure I-3.  Lognormal probability plot of prometryn field trial data
for cilantro.

Figure I-4.  Tolerance spreadsheet summary of prometryn field trial data
for cilantro.

Parsley

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-day PHI.  The field trial application rates and PHIs are within 25% of
the maximum label application rate and minimum label PHI, respectively. 
The residue values that were entered into the tolerance spreadsheet are
provided in Table I-3.

Because 2 of 8 field trial sample results for parsley (first and second
cuts) were below LOQ, MLE procedures were needed to impute censored
values for parsley.  The parsley dataset was small (8 samples).  For
parsley, visual inspection of the lognormal probability plot (Figure
I-5) and the result from the approximate Shapiro-Francia test statistic
(Figure I-6) indicated that the assumption of lognormality should be
rejected.

Because the dataset was not lognormal, the upper bound on the 89th
percentile was selected as the tolerance value (distribution-free
method).  Using the tolerance spreadsheet, the recommended tolerance is
0.60 ppm for parsley.

Table I-3.	Residue data used to calculate tolerance for residues of
prometryn on parsley.

Regulator:	EPA

Chemical:	Prometryn

Crop:	Parsley (1st and 2nd cuts) (MLE)

PHI:	30-32 days

App. Rate:	1.5 lb ai/A

Submitter:	IR-4

MRID Citation:	MRID 47548703

	Residues of Prometryn (ppm)

	0.028

	0.040

	0.187

	0.338

	0.323

	0.339

	0.216

	0.257

Figure I-5.  Lognormal probability plot of prometryn field trial data
for parsley.

Figure I-6.  Tolerance spreadsheet summary of prometryn field trial data
for parsley.

Prometryn	Summary of Analytical Chemistry and Residue Data	DP#:  357094

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