Document ID: EPA-HQ-OPP-2007-0894-0007
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2008-09-17T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

OFFICE OF           

PREVENTION, PESTICIDES

AND TOXIC SUBSTANCES

MEMORANDUM

	Date:	05/12/08

	Subject:	Ethoprop.  Petition for Registration of Uses on Mint and Hops.
 Summary of Analytical Chemistry and Residue Data.  

PC Code:  041101	DP Barcode:   352231 and 352233

Decision No.: 382076, 299884	Registration No.: 264-458, 264-457, and
264-469

Petition No.: 5E4491 and 7E7247	Regulatory Action: New
Registration/Tolerance

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

TXR No.: N/A	CAS No.: 13194-48-4

MRID No.: 47194001, 43588801, 43588802	40 CFR:  180.262

	From:	Felecia Fort, Senior Chemist

		Christine L. Olinger, Senior Chemist

		Reregistration Branch I

		Health Effects Division (7509P)

	Through:	Toiya Goodlow, Chemist

		Reregistration Branch I

		Health Effects Division (7509P)

		Michael S. Metzger, Chief

		Reregistration Branch I

		Health Effects Division (7509P)

	To:	Susan Stanton

		Risk Integration, Minor Use & Emergency Response Branch

		Registration Division (7505P)

This document was originally prepared under contract by Dynamac
Corporation (1910 Sedwick Road, Building 100, Suite B, Durham NC 27713;
submitted 12/03/2007).  The document has been reviewed by the Health
Effects Division (HED) and revised to reflect current Office of
Pesticide Programs (OPP) policies.

Executive Summary

  SEQ CHAPTER \h \r 1 Ethoprop [S,S-dipropyl O-ethyl phosphorodithioate]
is an organophosphate insecticide/nematicide registered for use on a
variety of crops for the control of soil pests.  Ethoprop is
manufactured by Bayer CropScience under the trade name MOCAP® and is
formulated as either an emulsifiable concentrate (EC) or a granule (G). 

In the current petitions, Interregional Research Project No. 4 (IR-4) is
proposing the use of ethoprop as a 6 lb/gal EC formulation (EPA Reg. No.
264-458) on hops and mint and as a 15% G formulation (EPA Reg. No.
264-457) on mint.  The proposed use on hops is for a single broadcast or
banded soil application at up to 3.0 lb ai/A.  Applications to new hop
plantings can be made pre-plant or preemergence, and applications to
established hop yards can be made either early in the season, prior to
stringing vines, or after vine harvest.  The proposed preharvest
interval (PHI) is 90 days for hops.  The proposed use on mint is for a
single broadcast soil application at up to 6.0 lb ai/A, either
preplanting to new fields or after the final harvest of the season to
established mint fields.  The proposed PHI is 225 days for mint.  For
both hops and mint, only ground equipment is allowed for application,
and ethoprop must be incorporated into soil following application.  In
conjunction with these uses, IR-4 is proposing the following permanent
tolerances for ethoprop:

Hop, dried cones	0.02 ppm

Mint, hay	0.02 ppm

Permanent tolerances are established for residues of ethoprop per se
in/on a variety of plant commodities at 0.02 ppm.

  SEQ CHAPTER \h \r 1   SEQ CHAPTER \h \r 1 The qualitative nature of
the residue in plants is adequately understood based on cabbage, corn,
and potato metabolism studies.  HED concluded that for acute and chronic
non-cancer dietary risk, the residues of concern in crops are parent and
Metabolites II and III (S-ME and O-ME); for cancer dietary risk, the
residues of concern are parent and Metabolites II through IV (S-ME, O-ME
and M-1).

The qualitative nature of the residue in livestock is adequately
understood based upon acceptable ruminant and poultry metabolism
studies.  Residues of potential concern detected were Metabolites III
and/or IV, which together accounted for ≤2% of the total radioactive
residues in liver of hens and goats.  As the proposed uses on hops and
mint do not include any regulated livestock feedstuffs, issues
pertaining to livestock metabolism, analytical methods and storage
stability data for animal commodities, and residues in livestock
commodities are not relevant to the current petitions.

Adequate analytical methodology is available for enforcing tolerances of
ethoprop as currently defined.  Two Gas Chromatography (GC)/sulfur
microcoulometric detection methods are available in PAM, Vol. II (Method
I and A), which both involve solvent extraction and clean-up by sweep
co-distillation.  The reported limit of quantitation (LOQ) for most
commodities is 0.01 ppm for these methods.  Another GC/flame photometric
detection (FPD) method has also been proposed for determining residues
of ethoprop and Metabolite IV in plant commodities.  For this method,
residues are extracted with methanol and cleaned up using cation
exchange resin and nuchar/attaclay, and residues of Metabolite IV are
methylated with diazomethane.  Residues are then partitioned into
methylene chloride, further cleaned up using gel permeation and/or
silica gel chromatography, and determined using GC/FPD in the phosphorus
mode.  The LOQ is 0.01 ppm each for ethoprop and Metabolite IV in plant
commodities. This method has been adequately validated by an independent
laboratory, but has never undergone a petition method validation by the
Agency.

  

In the mint field trials and processing study, residues of ethoprop and
Metabolite IV were determined using a version of the above proposed
GC/FPD enforcement method.  The method was adequately validated in
conjunction with the analysis of field trial and processing study
samples, and the validated LOQ for residues of ethoprop and Metabolite
IV was 0.01 ppm in mint commodities.   

In the hop field trials, residues of ethoprop and Metabolites II, III
and IV were determined using a GC/FPD method that was derived from the
proposed GC/FPD enforcement method.  For this method, residues were
extracted with methanol, cleaned up using SCX and Nexus solid-phase
extraction (SPE) cartridges, and partitioned into ethyl acetate. 
Residues of Metabolite IV were ethylated using diazoethane, and all
residues then were cleaned up by NH2 SPE and determined by GC/FPD in the
phosphorous mode.  The validated LOQ for ethoprop and each metabolite
was 0.02 ppm in dried hops.  This method was adequately validated in
conjunction with the analysis of hops field trial samples.

Adequate storage stability data are available to support the mint and
hop field trials.  The data indicate that ethoprop and Metabolite IV are
stable under the conditions and durations of sample storage in the mint
field trials and processing study.  The data also indicate that ethoprop
and Metabolites II and III are stable under the conditions and durations
of sample storage in the hops field trials; however, Metabolite IV was
shown to degrade in dried hops stored at -20ºC.  Therefore, the residue
data on Metabolite IV in hops were corrected to account for declines of
0.15%/day during storage.

The submitted hops and mint field trial data are adequate and support
the proposed use patterns.  An adequate number of tests were conducted
on each crop in the appropriate geographical regions.  Samples were
analyzed for residues of concern using adequate data collection methods,
and the sample storage conditions and intervals are supported by the
available storage stability data.  Residues of ethoprop and Metabolite
IV (determined as methylated derivative) were determined in the mint
field trials and residues of ethoprop and Metabolites II, III and IV
(ethylated derivative) were determined in the hop field trials.

As quantifiable residues of ethoprop were detected (0.021 ppm) in mature
dried hops following soil applications at ~10x the proposed use rate,
the use on hops cannot be considered a non-food use.  However, because
ethoprop residues were just at or below the LOQ (0.02 ppm) following a
~10x application, the available field trial data will still support the
proposed 1x use rate, as ethoprop residues are unlikely to exceed the
LOQ in samples harvested at the proposed 90-day PHI.  Following
applications at 10x, residues of Metabolites II and III were each <0.02
ppm in/on dried hop cones, and residues of Metabolite IV (corrected for
storage declines) were <0.054-0.086 ppm. 

oil after the final harvest of the season, (ii) the application to
harvest interval is relatively long (≥225 days); and (iii) residues of
ethoprop in mint resulting from use of the EC were <LOQ at up to 10x the
proposed rate (see CHEMSAC meeting minutes of 1/16/08).    

The submitted mint processing study is adequate and indicates the
ethoprop residues may concentrate in mint oil by ~4x.  However, ethoprop
residues were <LOQ (<0.01 ppm) in/on mint tops (RAC) from all tests at
the 1x or 10x application rate.  When average ethoprop residues in oil
(0.038 ppm) from the 10x application are adjusted to account for the
exaggerated use rate, residues in oil (0.004 ppm) would be below the
proposed tolerance for mint tops.  Therefore, a separate tolerance is
not required for mint oil.

  SEQ CHAPTER \h \r 1 Although hops are a perennial crop, and therefore,
not rotated, mint is rotated with other crops, typically on a 3-5 year
interval; therefore, rotational crop data requirements are relevant to
the petition for use on mint.  Adequate confined and limited field
rotational crop studies are available and indicate that tolerances for
rotated crops are not required provided that labels are amended to
include a 30-day plantback intervals (PBI) for leafy vegetables, a
8-month PBI for small grains, and a restriction against the planting of
any root or tuber crops following ethoprop-treated crops.  None of the
registrant’s labels currently specify any rotational crop restrictions
for ethoprop.

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

No major deficiencies were noted in the subject petitions that would
preclude establishing permanent tolerances for residues of ethoprop per
se on hops and mint (peppermint and spearmint); however, label
amendments regarding rotational crop restrictions remain outstanding.
End-use labels for ethoprop must be amended to specify the recommended
PBIs for rotated crops. Tolerances should be established at 0.02 pm for
ethoprop in/on dried hop cones and tops of peppermint and spearmint.  A
human health risk assessment for ethoprop is forthcoming.

	Background

  SEQ CHAPTER \h \r 1 Ethoprop [S,S-dipropyl O-ethyl phosphorodithioate]
is an organophosphate  (OP) insecticide/nematicide registered for use on
bananas/plantains, beans (lima and snap), cabbage, citrus (non-bearing),
corn, cucumbers, peanuts, pineapples, potatoes, sugarcane, sweet
potatoes, and tobacco.  Ethoprop is manufactured by Bayer CropScience
under the trade name MOCAP® and is formulated as either an EC or G for
application to food/feed crops.  These products may be applied as
broadcast or banded preplant to preemergence applications and as banded
postemergence applications directed to the soil.  Use directions specify
the use of only ground equipment, except on potatoes where aerial
applications are allowed.

IR-4 previously submitted a petition requesting the use of ethoprop (EC
and G) on mint in the U.S. (PP#5E4491).  The mint petition was
originally submitted in 1995 and was reviewed by the Agency (DP#
D214091, G. Otakie, 8/14/1995), but later with the inception of FQPA was
rendered inactive pending completion of the OP cumulative risk
assessment.  Now that the cumulative risk assessment has been completed,
the petition has been reactivated.   Additionally, IR-4 has submitted a
new petition (PP#7E7247) requesting the use of ethoprop (EC) on hops in
the U.S.  In conjunction with these uses, IR-4 is proposing the
establishment of permanent tolerances for ethoprop residues on mint and
hops at 0.02 ppm.  The nomenclature and physicochemical properties of
ethoprop and its metabolites of concern are presented below in Tables 1
and 2.

Table 1.	Nomenclature of Ethoprop and its Metabolites of Concern.

Compound	

Common name	Ethoprop

Company experimental name	Ethoprop

IUPAC name	O-ethyl-S,S-dipropyl phosphorodithioate

CAS name	O-ethyl-S,S-dipropyl phosphorodithioate

CAS registry number	13194-48-4

End-use product (EP)	6 lb/gal EC (MOCAP® EC Nematicide-Insecticide, EPA
Reg. No. 264-458)

15% G (MOCAP® 15% Granular Nematicide-Insecticide, EPA Reg. No.
264-457)

Compound	

Common name	Metabolite II (ethoprop S-Me)

Chemical name	O-ethyl-S-methyl-S-propyl phosphorodithioate

Compound	

Common name	Metabolite III (ethoprop O-Me)

Chemical name	O-ethyl-O-methyl-S-propyl phosphorodithioate

Compound	

Common name	Metabolite IV (M-1)

Chemical name	O-ethyl-S-propyl phosphorodithioate

Table 2.	Physicochemical Properties of Technical Grade Ethoprop.

Parameter	Value	Reference

Boiling point	86-91ºC at 0.2 mmHg	Ethoprop Registration Standard
(10/20/87)

pH	6.65 in saturated aqueous solution at 21ºC

	Density	1.097 g/mL at 15ºC

	Water solubility	843 ppm at 21ºC

	Solvent solubility	Completely miscible in hexane, xylene, acetone, and
ethanol

	Vapor pressure	3.89 x 10-4 Torr at 24ºC

	Dissociation constant, pKa	not available

	Octanol/water partition coefficient, Log(KOW)	3.59 at 21ºC

	UV/visible absorption spectrum	not available

	

860.1200  Directions for Use

There are currently three end-use products of ethoprop registered to
Bayer CropScience for use in the U.S. on food/feed crops.  These EPs are
marketed under the trade name MOCAP® and include a 6 lb/gal EC (EPA
Reg. No. 264-458),  a 15% G (EPA Reg. No. 264-457), and a 20% G (EPA
Reg. No. 264-469).  IR-4 is proposing the use of the 6 lb/gal EC
formulation for an early-season broadcast or banded application to hops
for control of garden symphylan and long-horned beetle, and use of the 6
lb/gal EC and 15% G formulations for a post-harvest or preplant
broadcast soil application to mint for control of garden symphylan,
nematodes, and mint root borer.   Example use directions were provided
and are summarized below in Table 3.

Table 3.  Summary of Directions for Use of Ethoprop.

Applic. Timing, Type, and 

Equip. 1	Form.

[EPA Reg. No.]	Applic. Rate 

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

(lb ai/A)	PHI

(days)	Use Directions and Limitations

Hops

New plantings: Single broadcast pre-plant or preemergence soil
application to baby hops.

Established plantings:  single broadcast or banded soil application
prior to stringing vines or after harvest of vines.

Ground equipment only 	6 lb/gal EC

[264-458]	3.0	1	3.0	90	Incorporate into the top 2-4” of soil
immediately following application using mechanical means or by overhead
irrigation.

Mint

Single broadcast soil application, preplanting to new fields or after
last harvest of the season to established fields.

Ground equipment only	6 lb/gal EC

[264-458]

15% G

[264-457]	6.0	1	6.0	225	Incorporate into the top 2-4” of soil
immediately following application using mechanical means or by overhead
irrigation.

Apply in 20-30 gal/A.

1	Do not apply by air or through any type of irrigation equipment.  For
banded applications, rates per acre should be lowered to reflect actual
area treated.

Conclusions.  The label directions are adequate to allow evaluation of
the residue data relative to the proposed use.  The available hops and
mint field trial data support the proposed use directions. 

860.1300 Nature of the Residue - Plants

Ethoprop RED, DP# D239294, J. Abbots, 3/27/1998

  SEQ CHAPTER \h \r 1 The qualitative nature of the residue in plants is
adequately understood based on cabbage, corn, and potato metabolism
studies.  HED concluded that for acute and chronic non-cancer dietary
risk, the residues of concern in crops are parent and Metabolites II and
III (S-ME and O-ME); for cancer dietary risk, the residues of concern
are parent and Metabolites II through IV (S-ME, O-ME and M-1).  HED has
also determined that the metabolite ethyl phosphate is not a residue of
concern.

860.1300 Nature of the Residue - Livestock

Ethoprop RED, DP# D239294, J. Abbots, 3/27/1998 

 together accounted for ≤2% of the total radioactive residues in liver
of hens and goats.  Based on the data from the livestock metabolism
studies, the Agency has concluded finite residues of ethoprop are
unlikely to occur in livestock commodities [40 CFR 180.6(a)(3)].

860.1340 Residue Analytical Methods

Ethoprop RED, DP# D239294, J. Abbots, 3/27/1998

DP# D244335, S. Piper, 10/22/98 

Enforcement methods.    SEQ CHAPTER \h \r 1 Adequate analytical
methodology is available for enforcing tolerances of ethoprop as
currently defined.  Method I in the Pesticide Analytical Manual (PAM),
Vol. II, is a GC/sulfur microcoulometric detection method that has
undergone a successful EPA method validation.  This method involves
solvent extraction and clean-up by sweep co-distillation.  Residues of
ethoprop are determined by GC using a sulfur microcoulometric detector. 
PAM, Vol. II also lists Method A, which uses the same principles as
Method I, but employs different parameters for extraction and gas
chromatography.  The limit of quantitation for ethoprop in or on plant
commodities is 0.01 ppm in each method.  

A newer GC/FPD method has also been proposed as an enforcement method
for determining residues of ethoprop and Metabolite IV in plant
commodities.  For this method, residues of ethoprop and Metabolite IV
are extracted with methanol, filtered, and cleaned up using cation
exchange resin and nuchar/attaclay.  Residues are concentrated and
redissolved in methanol, and Metabolite IV is methylated with
diazomethane.  Ethoprop and methylated Metabolite IV are then
partitioned into methylene chloride, concentrated, redissolved in
methylene chloride, and further cleaned up using gel permeation and/or
silica gel chromatography prior to analysis using GC/FPD in the
phosphorus mode.  The LOQ is 0.01 ppm each for ethoprop and Metabolite
IV in plant commodities. This method has been adequately validated by an
independent laboratory, but has never undergone a petition method
validation by the Agency.

  

Data collection methods.  In the mint field trials and processing study,
residues of ethoprop and Metabolite IV were determined using a version
of the proposed GC/FPD enforcement method for plant commodities, which
is discussed above.  The validated LOQ for residues of ethoprop and
Metabolite IV was 0.01 ppm in mint commodities.   The method was
adequately validated in conjunction with the analysis of field trial and
processing study samples.

Residues of ethoprop and Metabolites II, III and IV were determined in
the hop field trials using a GC/FPD method that was derived from the
proposed GC/FPD enforcement method for lima beans.  For this method,
residues were extracted with methanol and initially cleaned up by
elution through tandem SCX and Nexus SPE cartridges.  Residues were then
concentrated, acidified and partitioned into ethyl acetate, and residues
of Metabolite IV were ethylated using diazoethane.  Residues were next
cleaned up using an NH2 SPE cartridge and then determined by GC/FPD in
the phosphorous mode, using external standards.  Residues are expressed
in terms of the individual analytes.  The validated LOQ for ethoprop and
each metabolite was 0.02 ppm in dried hops.  The above method was
adequately validated in conjunction with the analysis of hops field
trial samples.

Conclusions.  Adequate methods are available for enforcing the proposed
tolerances on hops and mint, and the GC/FPD methods used for collecting
residue data from the field trials and mint processing study are
adequate for data collection.

860.1360 Multiresidue Methods

Acceptable multiresidue method testing data were submitted for ethoprop
and these data were forwarded to the U.S. FDA for further evaluation
(DP# 177243, L. Cheng, 5/28/1992).  Ethoprop is completely recovered
using Method 303, but is poorly recovered (≤50-80%) through 303 and
very poorly recovered (<50%) through protocol 304 (PAM Vol 1).

860.1380 Storage Stability

Ethoprop RED, DP# D239294, J. Abbots, 3/27/1998 

Adequate   SEQ CHAPTER \h \r 1 storage stability data are available
indicating that ethoprop per se is stable at -20ºC in cabbage, potato,
pineapple commodities, peanut commodities (except meal), and corn
commodities for up to 6 to 12 months, in sugar cane and its processed
fractions for up to 15 month, and in peanut meal for up to 3 months at
-20ºC.  At storage temperatures of -5ºC, ethoprop per se is stable for
6 to 12 months in the above commodities except for pineapple bran and
pulp, peanut hulls, and corn grain dust, in which ethoprop is stable for
<3 months.  

Metabolite IV is stable for ≤3 months at -20ºC in pineapple bran,
corn grain, corn fodder, corn starch, and in peanut meal, vine, hay, and
hulls.  At storage temperatures of -5ºC, Metabolite IV is stable for up
to 12 months in cabbage, pineapple juice, peanut nutmeat, peanut crude
oil, and corn crude oil.  Metabolite IV is stable at -5ºC for ≤3
months in potatoes; pineapple fruit, bran, and pulp; peanut meal, vine,
hay, hull, and refined oil; and corn grain, forage, fodder, starch,
meal, grain dust, and refined oil.

In the Ethoprop RED, HED concluded that concurrent storage stability
studies should be conducted with any required field trials or processing
studies.

As the mint field trials and processing study were conducted prior to
issuance of the Ethoprop RED, no concurrent storage stability data were
submitted with the mint studies.  However, the available stability data
on corn forage and oil and peanut hay and oil will support the mint
field trials and processing study.

 (↓0.15%/day).  Although no 0-day analyses were conducted on the
fortified samples prior to frozen storage, to verify the fortification
levels, the submitted storage stability data on dried hop cones is
adequate for purposes of this petition.  These data are in agreement
with the demonstrated stability of ethoprop and Metabolite IV on other
plant matrices.

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

≤-20	14.2	13.9 1

Mint tops and oil	Frozen	2.7	3-12 2

1	Supported by concurrent storage stability study.  The data indicate
that Metabolite IV should be corrected for decline during storage.

2	Supported by data on corn forage and oil and peanut hay and oil.

↓0.15% per day).  Therefore, the residue data on Metabolite IV were
corrected to account for decline during storage.

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

There are no livestock feedstuffs associated with the proposed uses on
mint or hops.  Therefore, data requirements pertaining to meat, milk,
poultry, and eggs are not relevant to these tolerance petitions.

860.1500 Crop Field Trials

DP# 214091, G. Otakie, 8/14/1995 (mint field trials)

47194001.der (hop field trials)

IR-4 previously submitted residue data from mint field trials, which
were reviewed by HED (DP# D218587, G. Otakie, 8/14/1995).  IR-4 has also
submitted new field trial data supporting a proposed use of ethoprop
(EC) on hops.    SEQ CHAPTER \h \r 1 The results from the mint and hop
trials are discussed below and the residue data are summarized in
Table 5.

Table 5.	Summary of Residue Data from Mint and Hops Field Trials with
Ethoprop (EC).

Crop matrix	Total Applic. Rate

(lb ai/A)	PHI (days)	Analyte 1	Residue Levels (ppm) 2

n	Min.	Max.	HAFT 3	Median	Mean	Std. Dev.

Hops (proposed use = 3.0 lb ai/A total application rate, 90-day PHI)

Hop, dried cones	30.1-34.3	118-135	Ethoprop	6	<0.02	0.021	0.02	0.02	0.02
<0.001

	M-1 4, 5	6	<0.054	0.086	0.077	0.054	0.062	0.013

	O-Me	6	<0.02	<0.02	<0.02	0.02	0.02	NA

	S-Me	6	<0.02	<0.02	<0.02	0.02	0.02	NA

Mint (proposed use = 6.0 lb ai/A total application rate, 255-day PHI)

Mint, tops	6.0	225-280	Ethoprop	15	<0.01	<0.01	<0.01	0.01	0.01	NA

	M-1 5	15	<0.01	0.073	0.061	0.01	0.02	0.021

1	Analytes M-1, O-Me and S-Me are respectively equivalent to Metabolites
IV, III and II.

2	The LOQ is ~0.02 ppm for each analyte in hops, and 0.01 ppm for parent
and M-1 (determined as M-1-Me) in mint.  For calculation of median, mean
and standard deviation, the LOQ was used for values <LOQ.

3	HAFT = Highest average field trial result.

4	Data corrected for 63% degradation.  The original data for the two
samples with detectable residues were 0.032 ppm and 0.025 ppm.

5	Metabolite M-1 was determined as ethylated M-1(M-1-Et)_ in the hop
field trials and as methylated M-1 in the mint field trials. 

Hops.   In 3 field trials conducted during 2005 in Zones 11 and 12,
ethoprop (6 lb/gal EC) was applied to hop fields as either a single
broadcast soil application at 30.1 or 34.3 lb ai/A (~10x rates, 2 tests)
or as two banded soil applications (1 test) at 14.0 and 16.6 lb
ai/A/application at a retreatment interval of 6 days, for a total of
30.6 lb ai/A (10x rate).  The 10x application rates were used in these
field trials because the petitioner was attempting to demonstrate that
the proposed use could be considered a non-food/feed use.  The
applications were made early in the growing season, prior to stringing
vines when either some foliage was present or after pruning off new
growth.  Applications were made using ground equipment at 14-50 gal/A,
and did not include the use of any spray adjuvants.  Following
application, the ethoprop was incorporated into the soil by
irrigation/rainfall.

(↓0.15%/day) in hops during frozen storage; therefore, the reported
residues of M-1 have been corrected for decline during storage.

Residues of ethoprop and its metabolites M-1, O-Me, and S-Me in/on dried
hop cones were determined using a GC/FPD method that was adequately
validated prior to and in conjunction with the analysis of the field
trial samples.  The LLMV was 0.02 ppm for each analyte and the
calculated LOQ and LOD were respectively 0.02 and 0.007 ppm for
ethoprop, 0.023 and 0.008 ppm for Metabolites M-1 (determined at
M-1-Et), 0.011 and 0.004 ppm for O-Me, and 0.026 and 0.009 ppm for S-Me.

he proposed use rate, residues of ethoprop were ≤0.021 ppm in/on 6
samples of dried hop cones harvested at 118-135 DAT, with residues >LOQ
in only one sample (0.021 ppm).  Residues of the Metabolites S-Me and
O-Me were each <0.02 ppm in/on all samples.  Residues of M-1, determined
as M-1-Et and corrected for storage declines, were <LOQ in/on 4 samples
and 0.068 and 0.086 ppm in two samples from one test.  Average residues
were calculated to be 0.02 ppm for parent, O-Me, and S-Me and 0.062 ppm
for M-1-Et.  Residue decline data were not reported for hops; however,
these data are not required as the applications were made to the soil
and the treatment to harvest interval was fairly long (>100 days).

Mint.  Five field trials were conducted on mint in Zones 5, 11 and 12
during 1993-1994.  In each field trial, ethoprop (6 lb/gal EC) was
applied to established fields of mint as a single broadcast application
at 6.0 lb ai/A (1x proposed rate) in the fall following the final
harvest.  Single control and triplicate treated samples of mint hay were
collected from the first harvest the following season, at 225-280 DAT. 
Samples were stored frozen for up to 82 days, an interval supported by
available storage stability data.

Mint samples were analyzed for residues of ethoprop and Metabolite M-1
using a GC/FPD method similar to a method that has previously been
proposed for tolerance enforcement.   The method was adequately
validated in conjunction with the analysis of the field trial samples. 
The validated LOQ is 0.01 ppm for both ethoprop and Metabolite M-1 in
mint.  

Following a single broadcast soil application of ethoprop at 6.0 lb ai/A
(1x proposed rate) in the fall after the last harvest, residues of
ethoprop were <0.01 ppm in/on all samples of mint collected from the
first harvest in the following season (225-280 DAT).  Residues of M-1
were also <0.01 ppm in/on mint from four field trials (n=12), but were
detected at up to 0.073 ppm from one field trial in WI (HAFT residues =
0.061 ppm).

 

Conclusions.  The hops and mint field trial data are adequate and
support the proposed use patterns.  An adequate number of tests were
conducted on each crop in the appropriate geographical regions.  Samples
were analyzed for residues of concern using adequate data collection
methods, and the sample storage conditions and intervals are supported
by the available storage stability data.

≤0.021 ppm following a ~10x application, the available field trial
data will still support the proposed 1x application of ethoprop (EC) to
hops as ethoprop residues are unlikely to exceed the LOQ in samples
harvested at the proposed 90-day PHI.

≥225 days); and (iii) residues of ethoprop in mint resulting from use
of the EC were <LOQ at up to 10x the proposed rate (see processing study
below).

  

The available hop and mint field trial data will support tolerances for
residues of ethoprop per se in/on mint tops (spearmint and peppermint)
and dried hop cones at 0.02 ppm.

860.1520 Processed Food and Feed

DP# 214091, G. Otakie, 8/14/1995

In a mint processing study conducted in OR during 1993-1994, ethoprop (6
lb/gal EC) was applied to established mint at the 4-6 leaf stage as a
single broadcast application in the fall at rates of 30 or 60 lb ai/A
(5x and 10x rates).  Samples of control hay and treated hay from the 10x
plot were harvested 225 DAT.  Hay was processed into oil and spent hay
on the day of harvest using standard commercial distillation practices. 
Samples were stored frozen for up to 82 days prior to analysis, an
interval supported by available storage stability data.  

Samples of mint hay, oil and spent hay were analyzed for residues of
ethoprop and Metabolite M-1 using the same GC/FPD method as used in the
mint field trials.   The method was adequately validated in conjunction
with the analysis of the processing study samples.  The validated LOQ is
0.01 ppm for both ethoprop and Metabolite M-1 in mint hay, oil and spent
hay.

Following a 10x application, residues of both ethoprop and M-1 were <LOQ
(<0.01 ppm) in mint hay (RAC) and spent hay.  Residues of Metabolite M-1
were also <0.01 ppm in mint oil.  Residues of ethoprop were detected in
mint oil at a maximum of 0.044 ppm and averaged 0.038 ppm following an
application at 10x.  Assuming residues at the LOQ for mint hay, the
processing factor for ethoprop in mint oil is 4x.

Conclusions.  The mint processing study is adequate.  Average residues
of ethoprop were 0.038 ppm in mint oil processed from mint treated at a
10x rate.  Because ethoprop residues were <LOQ (<0.01 ppm) in all
samples of mint from the 1x rate and 10x rate field trials, the maximum
expected residues in oil at a 1x rate were estimated using the 10x field
trial data and adjusting for the degree of exaggeration.  Accordingly,
the maximum expected residues on mint oil would be 0.0038 ppm, which is
below the proposed 0.02 ppm tolerance for mint.  Therefore, a separate
tolerance is not required for mint oil.

 

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

An analytical reference standard for ethoprop is currently available at
the EPA National Pesticide Standards Repository (correspondence with
Theresa Cole 9/18/2007).

860.1850 Confined Accumulation in Rotational Crops

Ethoprop RED, DP# D239294, J. Abbots, 3/27/1998 

  SEQ CHAPTER \h \r 1 An adequate confined rotational crop study is
available and indicates that residues of ethoprop in rotational crops
are qualitatively similar to the residues resulting from the direct
application of ethoprop to the primary crops.  Ethoprop residues of
concern were detected at >0.01 ppm in/on spinach from the 31-day
plant-back interval, radish roots and wheat straw from 31- and 123-day
PBIs, and wheat forage from 31-, 123, and 365-day PBIs.  Based upon
results of the confined rotational crop study, limited field
accumulation studies in rotational crops were required.  

860.1900 Field Accumulation in Rotational Crops

Ethoprop RED, DP# D239294, J. Abbots, 3/27/1998

DP# D238977, J. Abbotts, 1/23/1998

DP# D245393, S. Piper, 10/07/1998

Rotational crop data are not relevant to the proposed use on hops, as
hops are a perennial crop.  However, mint fields are rotated with other
crops, typically on a 3-5 year interval.  None of the registrant’s
labels currently specify any rotational crop restrictions for ethoprop. 

Adequate data are available from limited rotational crop field trials. 
Based on the results of this study and the registrant’s response to
the Agency’s review of the limited field trials, HED has concluded
that a 30-day plantback restriction is appropriate for leafy vegetables
and an 8-month plantback restriction is for small grains.  In addition,
the registrant has indicated that the label will be amended to prohibit
rotation to any root or tuber crops following application of ethoprop. 
Provided that labels are amended to include these restrictions, no
additional data or tolerances would be required for rotational crops.  

860.1550 Proposed Tolerances

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:e Residue Chemistry Chapter for the Ethoprop RED (J. Abbotts, 3/27/98)
previously recommended that the tolerance expression for ethoprop be
revised to include residues of both parent and Metabolite IV (M-1),
expressed as parent.  However, HED has since revised it position and is
now recommending that the tolerance expression include only parent
ethoprop (DP# D277780, C. Swartz, 10/11/2001).

Based on the available field trial data, the tolerance for dried hop
cones should be set at the LOQ for the enforcement method (0.02 ppm) as
residues of ethoprop were either <LOQ (<0.02 ppm) or just above the LOQ
(0.021 ppm) in samples from the 10x rate field trials (Table 6). 
Similarly, tolerances for mint (peppermint and spearmint) should be set
at the LOQ (0.02 ppm) as residues of ethoprop were <0.01 ppm in all
samples of mint hay from the 1x rate field trials.  Separate tolerances
should be established for peppermint tops and spearmint tops, rather
than on mint.  Based on the results of the mint processing study, a
separate tolerance is not required for mint oil.

There are no Canadian or Mexican MRLs for residues of ethoprop and no
Codex MRLs for residues of ethoprop on the proposed crops (see IRL
sheet).  Therefore, there are no international harmonization issues
associated with these petitions.

Table 6. 	Tolerance Summary for Ethoprop.

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

Hop, dried cones	0.02	0.02	Adequate Residue Data are available. Hop,
cones, dried

Mint, hay	0.02	0.02	Adequate residue data are available.  Separate
tolerances should be established for spearmint, tops and peppermint,
tops

References

  SEQ CHAPTER \h \r 1 DP Number:	D214091

Subject:	  SEQ CHAPTER \h \r 1 PP#5E04491 - Ethoprop on Mint -
Evaluation of Field Trial and Processing Residue Data.

From:		G. Otakie

To:		D. Edwards, C. Anderson, and W. Hazel

Dated:		8/14/1995

MRID(s):	43588801 and 43588802

  SEQ CHAPTER \h \r 1 DP Number:	D238977

Subject:	Ethoprop (041101), Reregistration Case No. 0106.  Registrant
Rhône-Poulenc Ag Company.  Residue Chemistry Guideline 860.1900,
Limited Rotational Crop Field Trials.  SEQ CHAPTER \h \r 1 

From:		J. Abbots

To:		K. Farwell and J. Loranger

Dated:		1/23/1998

MRID(s): 	44350201

  SEQ CHAPTER \h \r 1 DP Number:	D239294

Subject:	  SEQ CHAPTER \h \r 1 Ethoprop (041101), Reregistration Case
No. 0106. Product and Residue Chemistry Chapters for the Reregistration
Eligibility Decision (RED).

From:		J. Abbots

To:		K. Farwell

Dated:		3/27/1998

MRID(s):	None

  SEQ CHAPTER \h \r 1 DP Number:	D245393

Subject:	  SEQ CHAPTER \h \r 1 Ethoprop (041101).  Reregistration Case
No 0106.  Registrant Rhone-Poulenc Ag Company.  Registrant’s Response
to Limited Rotational Crop Field Trials.

From:		S. Piper

To:		M. Metzger

Dated:		10/07/1998

MRID(s):	None

  SEQ CHAPTER \h \r 1 DP Number:	D244335

Subject:	  SEQ CHAPTER \h \r 1 Ethoprop (041101).  Reregistration Case
No 0106.  Revision of the Enforcement Method for Ethoprop on Lima Bean
Pods, Vines, and Hay.

From:		S. Piper

To:		M. Metzger

Dated:		10/22/1998

MRID(s):	44495601

  SEQ CHAPTER \h \r 1 DP Number:	D277780

Subject:	  SEQ CHAPTER \h \r 1 Ethoprop.  List A Reregistration Case No.
0106/Chemical ID No. 041101). Data Requirements and Tolerance
Reassessment for the IRED.

From:		C. Swartz

To:		K. Farwell and B. Gregg

Dated:		10/11/2001

MRID(s):	None

  SEQ CHAPTER \h \r 1 Attachments:  

International Residue Limit Status sheet

Template Version September 2005



INTERNATIONAL RESIDUE LIMIT STATUS

Chemical Name: 

O-ethyl-S,S-dipropyl phosphorodithioate	Common Name: Ethoprop

	( Proposed tolerance

□ Reevaluated tolerance

□ Other	Date:  11/30/07

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

□ No Codex proposal step 6 or above

( No Codex proposal step 6 or above for the crops requested	Petition
Numbers:  5E4491, 7E7247

DP#s:  342754, 342793

Other Identifier:  

Residue definition (step 8/CXL):  Ethoprophos	Reviewer/Branch:  M.
Sahafeyan/RAB1

	Residue definition:  Ethoprop 

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

Hop, cones, dried	0.02

Peppermint, tops	0.02

Spearmint, tops	0.02

Limits for Canada	Limits for Mexico

(  No Limits

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	□  No Limits for the crops requested	(  No Limits

□  No Limits for the crops requested

Residue definition:  N/A	Residue definition:  NA

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

	Notes/Special Instructions: 

Page   PAGE  17  of   NUMPAGES  17 

Ethoprop	Summary of Analytical Chemistry and Residue Data	Barcode: 
352231, 352233