Document ID: EPA-HQ-OPP-2008-0362-0006
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-04-01T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

	OFFICE OF PREVENTION, 

	PESTICIDES AND TOXIC

SUBSTANCES

MEMORANDUM

Date:		11/06/2008

Subject:		Quinoxyfen.  Petition for Tolerances and Uses on Winter Squash
(including Pumpkin and Edible Gourd), Artichoke, and Stone Fruit (Group
12) (PP#8E7325).  Summary of Analytical Chemistry and Residue Data.

PC Code:  055459	DP Barcode: 354559

MRID No.:  47340601-04	Decision No.: 390599

Petition No.: PP#8E7325	Regulatory Action: Section 3 - PRIA

Assessment Type: None	Reregistration Case No.: None

TXR No.: None	CAS No.: 124495-18-7

From:		Donald Wilbur, Chemist

		Reregistration Branch 2 (RRB2)

		Health Effects Division (HED 7509P)

	Through:	Sheila Piper, Chemist

		Felecia Fort, Branch Chief

		Reregistration Branch 2 (RRB2)

		Health Effects Division (HED 7509P)

To:	        John Redden, Team Leader

	        Risk Integration Minor Use Emergency Response Branch (RIMUERB)

	        Registration Division (RD 7505P)

Executive Summary

Quinoxyfen (5,7-dichloro-4-(4-fluorophenoxy)quinoline) is a systemic
quinoline fungicide.  Its proposed mode of action is the inhibition of
GTP-binding proteins (G-proteins) in intracellular signaling. 
Quinoxyfen was developed for the control of powdery mildews on a variety
of crops.  Permanent tolerances are established for residues of
quinoxyfen per se [40 CFR §180. 588 (a)] in/on cherries (0.30 ppm);
grapes (0.60 ppm); hop, dried cones (3.0 ppm); lettuce, head (7.0 ppm);
lettuce, leaf (19 ppm); pepper, bell (0.35 ppm); pepper, nonbell (1.7
ppm); strawberry (0.90 ppm); and melon subgroup 9A (0.08 ppm). 
Time-limited tolerances are established for residues of quinoxyfen per
se [40 CFR §180. 588 (b)] in/on pumpkin (0.30 ppm); and squash, winter
(0.30 ppm).

The Interregional Research Project No. 4 (IR-4) has submitted a petition
(PP#:8E7325) proposing the use, formulated as Quintec®, 22.58%
quinoxyfen suspension concentrate (SC), on winter squash (including
pumpkins and edible gourds), artichoke, and stone fruit (group 12).

The proposed uses include four foliar applications at 0.13 lb
a.i./A/application (total of approximately 0.52 lb a.i./A (0.58 kg
ai/ha)) with retreatment intervals (RTI) of 6-8 days and pre-harvest
intervals (PHIs) of 0-7days.  In conjunction with these uses, IR-4 is
proposing tolerances for residues of quinoxyfen per se in/on winter
squash (including pumpkins and edible gourds) at 0.2 ppm; artichoke at
1.4 ppm; and fruit, stone, group 12 at 0.70 ppm.

Based on the previously-submitted cucumber, grape, sugar beet, and
tomato metabolism studies, the nature of the residue in plants is
adequately understood for the purposes of this petition only. The
residue of concern is quinoxyfen per se. 

  SEQ CHAPTER \h \r 1 An adequate gas chromatography with mass-selective
detection (GC-MSD) method is available for enforcing the proposed
quinoxyfen tolerances (DowElanco Procedure ERC95.26).  The general
procedure of this method involves extraction of the sample with acidic
acetone, partitioning with hexane, purification of the extract by
amino-propyl solid-phase extraction (SPE) column chromatography, and
analysis of the extract by GC-MSD.  The lowest level of method
validation (LLMV) is 0.01 ppm. 

The field trials on artichoke, peach, plum, and winter squash are   SEQ
CHAPTER \h \r 1 adequate.  An adequate number of trials were conducted
reflecting the proposed use patterns in the appropriate geographic
regions, and the appropriate commodities were collected at the proposed
PHIs.  Samples were analyzed using adequate analytical methods, and the
sample storage intervals are supported by the available storage
stability data.  The available artichoke data will support a tolerance
for residues of 1.4 ppm on artichoke, globe; the peach and plum data
will support a tolerance for residues of 0.70 ppm on fruit, stone, group
12; and the winter squash data will support a tolerance for residues of
0.20 ppm on squash, winter, pumpkin, and gourd, edible.  The petitioner
did not submit any crop field trial data for pumpkin or edible gourd,
but based on the Reviewers Guide and Summary of HED ChemSAC Approvals
for Amending Commodity Definitions (B. Schneider, 06/14/2002) those
specific commodities are included in the definition for winter squash.

Adequate confined and field rotational crop studies are not available. 
Crops having quinoxyfen tolerances may be replanted at any time. 
Rotation to all other crops is prohibited.

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

Provided a revised Section B is submitted reflecting the rotational crop
restriction, HED concludes there are no residue chemistry data
requirements that would preclude establishing unconditional
registrations and permanent tolerances for residues of quinoxyfen at 1.4
ppm on artichoke, globe; 0.70 on fruit, stone, group 12; and 0.20 on
squash, winter; pumpkin; and gourd, edible.

A human-health risk assessment will be prepared in a separate document.

Background

Quinoxyfen is a systemic quinoline fungicide.  Its proposed mode of
action is the inhibition of GTP-binding proteins (G-proteins) in
intracellular signaling.  Quinoxyfen was developed for the control of
powdery mildews on a variety of crops.  Permanent tolerances are
established for residues of quinoxyfen per se [40 CFR §180. 588 (a)]
in/on cherries (0.30 ppm); grapes (0.60 ppm); hop, dried cones (3.0
ppm); lettuce, head (7.0 ppm); lettuce, leaf (19 ppm); pepper, bell
(0.35 ppm); pepper, nonbell (1.7 ppm); strawberry (0.90 ppm); and melon
subgroup 9A (0.08 ppm).  Time-limited tolerances are established for
residues of quinoxyfen per se [40 CFR §180. 588 (b)] in/on pumpkin
(0.30 ppm); and squash, winter (0.30 ppm).

The Interregional Research Project No. 4 (IR-4) has submitted a petition
(PP#:8E7325) proposing the use, formulated as Quintec®, 22.58%
quinoxyfen suspension concentrate (SC), on winter squash (including
pumpkins and edible gourds), artichoke, and stone fruit (group 12).

Fruit, stone, group 12	0.70 ppm

Squash, winter	0.20 ppm

Pumpkin	0.20 ppm

Gourd, edible	0.20 ppm

Artichoke, globe	1.4 ppm

  SEQ CHAPTER \h \r 1 The nomenclature and physicochemical properties of
quinoxyfen are presented below in Tables 1 and 2.

 

TABLE 2.  Physicochemical Properties of the Technical Grade Test
Compound.

Parameter	Value1

Molecular Weight	308.13

Melting point/range	106.0ºC-107.5ºC

pH	7.97 (1% solution in water @ 22.7°C)

Density 	1.097 g/cm3 @ 20°C

Vapor pressure	1.2x 10-5 Pa @ 20°C

Log10 KOW (Log P)	4.66 @ 20°C

Solubility	0.116 mg/L @ 20°C in distilled water

0.128 mg/L @ 20°C in water (pH 5)

0.047 mg/L @ 20°C in water (pH 7)

0.036 mg/L @ 20°C in water (pH 5)

9.64 mg/L @ 20°C in n-hexane

21.5 mg/L @ 20°C in methanol

179 mg/L @ 20°C in ethyl acetate

272 mg/L @ 20°C in toluene

116 mg/L @ 20°C in acetone

589 mg/L @ 20°C in dichloromethane

Dissociation Constant	Ka = 2.77 x 10-4, pKa = 3.56

1Smith, Amy J., Group B: Physical and Chemical Properties of Quinoxyfen
(DE-795) and Supplemental Properties of 3-Hydroxy-XDE-795, Dow
AgroSciences, LLC, 20 December 2000.

860.1200 Directions for Use.

There is currently one quinoxyfen end-use product (EP) registered to Dow
Agrosciences LLC for use on food/feed crops:  Quintec®, a 22.58% ai SC
(EPA Reg. No. 62719-375).  IR-4 is supporting the use of Quintec® on
winter squash (including pumpkins and edible gourds), artichoke, and
stone fruit (group 12).  Example labels were provided and the proposed
use directions are summarized below in Table 3.

Table 3.	Summary of Proposed Use Directions for Quinoxyfen.

Application Timing, Type and Equipment	

Formulation

[EPA reg. No.]	Single rate

(lb ai/A)	Max Number Applications per Season	Max. Seasonal Application
Rate (lb ai/A)	

PHI (Days)	Use Directions and Limitations 1

Artichoke

Directed foliar applications 

Ground equipment	Quintec®

[62719-375]	0.13	4	0.52	0	The minimum RTI is 6-7 days.

Winter Squash

Directed foliar applications 

Ground equipment	Quintec®

[62719-375]	0.13	4	0.52	3	The minimum RTI is 6-8 days.

Stone Fruit (group 12)

Directed foliar applications 

Ground equipment	Quintec®

[62719-375]	0.13	4	0.52	7	The minimum RTI is 6-8 days.

1   Crops having quinoxyfen tolerances may be replanted at any time. 
Rotation to all other crop tolerances is prohibited.

  SEQ CHAPTER \h \r 1 Conclusions.  The proposed use directions on
winter squash (including pumpkins and edible gourds), artichoke, and
stone fruit (group 12) are adequately supported by the available residue
data except that the rotational crop restrictions are not listed on the
labels.  A revised Section B should be submitted.

860.1300 Nature of the Residue – Plants.

D276835,   SEQ CHAPTER \h \r 1 G. Kramer, 03/26/2003 

Dow AgroSciences submitted the results of plant metabolism studies
conducted on cucumber, grape, sugar beet, tomato, and winter wheat in
support of the proposed uses of quinoxyfen on grape and hops.  The
cucumber, grape, sugar beet, and tomato studies were determined to be
acceptable.  The wheat study (MRID 45360716) was determined to be
inadequate because of deficiencies in the submitted data for wheat
forage.

Based on acceptable cucumber, grape, sugar beet, and tomato metabolism
studies, the nature of the residue in plants is adequately understood
for the purposes of this petition only.  Quinoxyfen was the primary
residue component in all reviewed plant metabolism studies except in
wheat grain and straw where Metabolite A was the predominant residue. 
Metabolite A was determined not to be associated with the parent
quinoxyfen, or related compounds, but was characterized to be highly
polar and multi-component in nature.

In cucumber and tomato, unchanged quinoxyfen remained largely on the
surface of treated plants.  The presence of multiple unidentified polar
residues suggests that metabolism of quinoxyfen does occur to some
extent to form more polar soluble components with the incorporation into
insoluble material.  Degradates and conjugates may be incorporated into
natural constituents such as lignin and cellulose.  Minor differences in
the characterized residues (unknowns) from phenyl- and quinoline-labeled
crop commodities indicate that cleavage of the parent molecule between
the rings may occur at a minor level.  However, levels of unidentified
components were too low for the petitioner to conclusively define the
route of metabolism. 

Quinoxyfen appears to be metabolized in sugar beets to some extent and
may then be incorporated with natural plant constituents such as lignin.
 The initial breakdown of quinoxyfen on leaves may result from surface
photolysis and resulting photo-degradates may be further metabolized to
polar residues.  In addition, the ether bond of the quinoxyfen compound
may be broken during metabolism yielding the 4-fluorophenol and DCHQ
(5,7-dichloro-4-hydroxyquinoline) metabolites.

The results of the plant metabolism studies were forwarded to HED’s
Metabolism Assessment Review Committee (MARC) to determine the residues
of concern in plants.  MARC concluded that based on the
currently-available data, parent only is the residue of concern for
purposes of the tolerance expression and risk assessment (D227383, G.
Kramer, 03/26/2003).

860.1300 Nature of the Residue – Livestock.

There are no livestock feed items associated with on winter squash
(including pumpkins and edible gourds), artichoke, and stone fruit
(group 12)  Therefore, no livestock metabolism studies are required to
support these petitions.

860.1340 Residue Analytical Methods - Plants.

  SEQ CHAPTER \h \r 1 An adequate GC-MSD method is available for
enforcing quinoxyfen tolerances (DowElanco Procedure ERC95.26); a
successful petition method validation (PMV) has been completed (Memo, E.
Kolbe, 5/11/06; D285350).  The general procedure of this method involves
extraction of the sample with acidic acetone, partitioning with hexane,
purification of the extract by amino-propyl SPE column chromatography,
and analysis of the extract by GC-MSD.  The LLMV was 0.01 ppm. 

Residues of quinoxyfen in samples from the current crop field trials
were determined using modifications of DowElanco Procedure ERC95.26. 
Each of the above methods was validated in conjunction with the field
trials.  For artichokes fortified at 0.01, 0.10, and 1.0 ppm, average
recoveries were 95 ± 4%; for winter squash fortified at 0.01, 0.10, and
1.0 ppm, average recoveries were 92 ± 3%; for plum fortified at 0.01,
0.10, and 1.0 ppm, average recoveries were 95 ± 3%; and for peach
fortified at 0.01, 0.10, and 1.0 ppm, the average recovery was 91 ± 3%.

Conclusion.  The available GC-MSD method is adequate for collecting data
and enforcing tolerances for quinoxyfen residues in/on the subject
crops.

860.1340 Residue Analytical Methods - Livestock.

  SEQ CHAPTER \h \r 1 There are no livestock feed items associated with
this petition; therefore, data-collection and tolerance-enforcement
methods for livestock commodities are not required.

  SEQ CHAPTER \h \r 1 860.1360 Multiresidue Methods (MRM).

A study which investigated the behavior of quinoxyfen through MRMs
outlined in the Food and Drug Administration (FDA) Pesticide Analytical
Manual (PAM), Volume I, Appendix II was submitted previously.  The study
summary reported that, depending on spike levels, certain MRM Protocols
(D, E, and F) yielded partial (incomplete) to complete recoveries of
quinoxyfen in grapes (non-fatty matrix) and ground beef (fatty matrix). 
HED has forwarded this study to FDA for a complete evaluation (D285352,
G. Kramer, 09/20/2002).

860.1380 Storage Stability.

Adequate data are available indicating that quinoxyfen is stable during
frozen storage for 83 days in artichoke; 158 days in plums (pitted
fruit); 92 days in plums (dried pitted fruit); 183 days in peaches; and
109 days in winter squash.

 

To validate sample storage conditions and intervals, the petitioners
conducted concurrent storage stability studies.  The results of these
studies are reported in the respective magnitude of the residue DERs for
winter squash (47340603.DER.doc), peach (47340602.DER.doc), artichoke
(47340604.DER.doc) and plum (47340601.DER.doc).  The concurrent storage
stability studies are adequate to support the storage conditions and
intervals of collected samples.

Conclusion.  The available storage stability data are adequate to
support the sample storage intervals and conditions from the current
field trials. 

860.1480:  Meat/Milk/Poultry/Eggs

There are no livestock feed items associated with the proposed new uses
of quinoxyfen.  Data on residues of quinoxyfen in livestock tissues,
milk and eggs are not required to support these petitions.

860.1500 Crop Field Trials

artichoke (47340604.DER.doc)

winter squash (47340603.DER.doc)

peach (47340602.DER.doc)

plum (47240601.DER.doc)

IR-4 has submitted crop field trials supporting the use of quinoxyfen on
winter squash (including pumpkins and edible gourds), artichoke, and
stone fruit (group 12).     SEQ CHAPTER \h \r 1 The results from these
studies are discussed below and summarized in Table 4.

TABLE 4.	Summary of Residue Data from Field Trials with Quinoxyfen.

Commodity	Total 

Application Rate,

lb a.i./A	PHI (days)	Residue Levels (ppm)

	n	Min.	Max.	HAFT1	Median 	Mean 	Std. Dev.

Artichoke (~0.52 lb ai/A maximum application rate, 0-day PHI)

Artichoke	0.519-0.536	0	6	0.63	1.09	1.02	0.83	0.89	0.15

Winter Squash (~0.52 lb ai/A maximum application rate, 3-day PHI)

Winter Squash	0.519-0.536	3-4	10	0.027	0.106	0.106	0.059	0.062	0.029

Peach (~0.52 lb ai/A maximum application rate, 3-day PHI)

Peach	0.513-0.645	6-8	22	0.057	0.55	0.49	0.108	0.181	0.155

Plum (~0.52 lb ai/A maximum application rate, 1-day PHI)

Pitted Fruit	0.516-0.522	7	12	<0.01	0.095	0.091	0.010	0.024	0.031

Dried Pitted Fruit	0.522	7	1	0.03	0.03	0.03	NA	NA	NA

1Highest-Average Field Trial

Artichoke:  The Interregional Research Project No. 4 (IR-4) has
submitted field trial data to support a tolerance for quinoxyfen on
artichoke.  Three supervised field trials were conducted during the 2004
growing season with artichoke in CA (Region 10). In these trials, four
foliar applications of Quintec EF 1295 (22.58% quinoxyfen) were made at
a nominal rate of 0.13 lb ai/A (0.146 kg ai/ha) per application, for a
total of approximately 0.52 lb ai/A (0.58 kg ai/ha) per season.
Applications were made 6-7 days apart and mature flower heads were
harvested on the day of final application. No adjuvants or additives
were added to the spray mixture for any of the above applications. The
number and locations of field trials are in accordance with OPPTS
Guideline 860.1500.  

Residues of quinoxyfen were quantified using a method based on Dow
Elanco Europe (Letcombe Laboratory) Method ERC95.26, Determination of
DE-795 Residues in Grape Wine, Must and Pomace, with minor
modifications.  Artichoke samples were extracted with 20/80 of 0.12M
HCL/acetone, partitioned into hexane, and evaporated to dryness in a
40ºC water bath. After solid phase extraction (SPE) cleanup, the
extract was evaporated and reconstituted with 0.1% corn oil in
isooctane.  Quantitation was achieved by gas chromatography with mass
selective detection (GC-MS).  For method validation, control samples of
artichoke were fortified at levels of 0.01, 0.10 and 1.0 ppm. During
sample analysis, untreated artichoke was fortified at 0.10 ppm and 2.0
ppm for concurrent recovery spikes. The lowest level of method
validation (LLMV) was reported as 0.01 ppm. Based on recoveries of fresh
artichoke samples fortified at the LLMV, the limit of detection (LOD)
and the limit of quantitation (LOQ) calculated as 0.0033 ppm and 0.0099
ppm, respectively.  Concurrent recoveries of quinoxyfen on/in artichoke
ranged from 85-93% and method validation recoveries ranged from 86-108%.
The method is adequate for data collection.

In all trials, artichoke was harvested on the day of the final
application and analyzed within 83 days.  Analytical results show that
quinoxyfen residues ranged from 0.063 ppm to a maximum of 1.09 ppm on/in
zero-day PHI artichoke samples. No residue decline data were collected. 

Winter Squash:  The Interregional Research Project No. 4 (IR-4) has
submitted field trial data to support a tolerance for quinoxyfen on
winter squash.  Four supervised field trials were conducted in 2003 with
winter squash in CA (Region 10), NJ (Region 2), MD (Region 2), and OH
(Region 5). One additional supervised field trial was conducted in FL
(Region 3) in 2004. In all trials, four foliar applications of Quintec
EF 1295 (22.58% quinoxyfen) were made at a rate of 0.13 lb ai/A (0.146
kg ai/ha) per application, for a total of approximately 0.52 lb ai/A
(0.58 kg ai/ha). Applications were made 6-9 days apart and mature fruit
was harvested with a PHI of 3-4 days. No adjuvants or additives were
added to the spray mixture for any of the above applications. The number
and locations of field trials are in accordance with OPPTS Guideline
860.1500.  

Residues of quinoxyfen were quantified using a method based on Dow
Elanco Europe (Letcombe Laboratory) Method ERC95.26, Determination of
DE-795 Residues in Grape Wine, Must and Pomace, with minor
modifications.  Squash samples were extracted with 20/80 of 0.12M
HCL/acetone, partitioned into hexane, and evaporated to dryness in a
40ºC water bath. After solid phase extraction (SPE) cleanup, the
extract was evaporated and reconstituted with 0.1% corn oil in
isooctane.  Quantitation was achieved by gas chromatography with mass
selective detection (GC-MS).  For method validation, control samples of
squash were fortified at levels of 0.01, 0.10 and 1.0 ppm. During sample
analysis, untreated squash was fortified at 0.10 ppm for concurrent
recovery spikes. The lowest level of method validation (LLMV) was
reported as 0.01 ppm. Based on recoveries of fresh squash samples
fortified at the LLMV, the limit of detection (LOD) and the limit of
quantitation (LOQ) calculated as 0.0014 ppm and 0.0041 ppm,
respectively.  Concurrent recoveries of quinoxyfen on/in winter squash
ranged from 88-93% and method validation recoveries ranged from 89-101%.
The method is adequate for data collection.

In all trials, squash was harvested 3-4 days after the final application
and analyzed within 98 days.  Analytical results show that quinoxyfen
residues ranged from 0.027 ppm to a maximum of 0.106 ppm on/in 3-4 day
PHI squash samples. No residue decline data were collected.  

Peach:  The Interregional Research Project No. 4 (IR-4) has submitted
field trial data to support a tolerance for quinoxyfen on peach.  Eleven
supervised field trials were conducted with peach in CA (Region 10, four
trials), NJ (Region 2, two trials), NC (Region 2, two trials), MI
(Region 5), NY (Region 1), and TX (Region 6). In all trials, four foliar
applications of Quintec EF 1295 (22.58% quinoxyfen) were made at a rate
of 0.13 lb ai/A (0.146 kg ai/ha) per application, for a total of
approximately 0.52 lb ai/A (0.58 kg ai/ha). Applications were made 6-8
days apart and mature fruit was harvested with a PHI of 7 ± 1 days. One
additional application was made at the TX trial (for a total of five
applications) to allow the fruit to become mature. No adjuvants or
additives were added to the spray mixture for any of the above
applications. The number and locations of field trials are in accordance
with OPPTS Guideline 860.1500.  

Residues of quinoxyfen were quantified using a method based on Dow
Elanco Europe (Letcombe Laboratory) Method ERC95.26, Determination of
DE-795 Residues in Grape Wine, Must and Pomace, with minor
modifications.  Peach samples were extracted with 20/80 of 0.12M
HCL/acetone, partitioned into hexane, and evaporated to dryness in a
40ºC water bath. After solid phase extraction (SPE) cleanup, the
extract was evaporated and reconstituted with 0.1% corn oil in
isooctane.  Quantitation was achieved by gas chromatography with mass
selective detection (GC-MS).  For method validation, control samples of
peach fruit were fortified at levels of 0.01, 0.10 and 1.0 ppm. During
sample analysis, untreated peach fruit were fortified at 0.10 ppm and
0.50 ppm for concurrent recovery spikes. The lowest level of method
validation (LLMV) was reported as 0.01 ppm. Based on recoveries of fresh
peach samples fortified at the LLMV, the limit of detection (LOD) and
the limit of quantitation (LOQ) calculated as 0.0012 ppm and 0.0037 ppm,
respectively.  Concurrent recoveries of quinoxyfen on/in peach ranged
from 86-94% and method validation recoveries ranged from 87-97%. The
method is adequate for data collection.

In all trials, peach was harvested 6-8 days after the final application
and analyzed within 134 days.  Analytical results show that quinoxyfen
residues ranged from 0.057 ppm to a maximum of 0.55 ppm on/in 7±1 day
PHI peach samples. No residue decline data were collected.  

Plum:  The Interregional Research Project No. 4 (IR-4) has submitted
field trial data to support a tolerance for quinoxyfen on plum.  Four
supervised plum field trials were conducted in CA (Region 10), one trial
was conducted in MI (Region 5) and one trial was conducted in OR (Region
12). In all trials, four foliar applications of Quintec EF 1295 (22.58%
quinoxyfen) were made at a rate of 0.13 lb ai/A (0.146 kg ai/ha) per
application, for a total of approximately 0.52 lb ai/A (0.58 kg ai/ha).
No adjuvants or additives were added to the spray mixture for any of the
above applications. The number and locations of field trials are in
accordance with OPPTS Guideline 860.1500.  

Residues of quinoxyfen were quantified using a method based on Dow
Elanco Europe (Letcombe Laboratory) Method ERC95.26, Determination of
DE-795 Residues in Grape Wine, Must and Pomace.  Plum samples were
extracted with 20/80 of 0.12M HCL/acetone, partitioned into hexane, and
evaporated to dryness in a 40ºC water bath. After solid phase
extraction (SPE) cleanup, the extract was evaporated and reconstituted
with 0.1% corn oil in isooctane. Quantitation was achieved by gas
chromatography with mass selective detection (GC-MS).  

For method validation, control samples of dried pitted plum fruit and
pitted plum fruit were fortified at levels of 0.01, 0.10 and 1.0 ppm.
During sample analysis, untreated plum fruit were fortified at 0.10 ppm
for concurrent recovery spikes. The lowest level of method validation
(LLMV) was reported as 0.01 ppm for both dried pitted plum fruit and
pitted plum fruit. Based on recoveries of fresh plum samples fortified
at the LLMV, the limit of detection (LOD) and the limit of quantitation
(LOQ) calculated as 0.002 ppm and 0.005 ppm, respectively.  Concurrent
recoveries of quinoxyfen on/in pitted plum and dried pitted plum ranged
from 89-92% and 88-95%, respectively.  Method validation recoveries
ranged from 90-101% for quinoxyfen on/in pitted plum and from 99-110%
for quinoxyfen on/in dried pitted plum. The method is adequate for data
collection.

In all trials, plum was harvested 7-days after the final application and
analyzed within 89 (dried pitted fruit) to 147 (pitted fruit) days. 
Analytical results show that quinoxyfen residues ranged from below the
LLMV (<0.01 ppm) to 0.095 ppm on/in 7-day PHI pitted plum samples.  The
maximum reside found on dried pitted plum was 0.03 ppm. No residue
decline data were collected.  

An estimated concentration factor of 3.5x was calculated for quinoxyfen
in dried pitted plum.

Conclusions.  The field trials on artichoke, peach, plum, and winter
squash are   SEQ CHAPTER \h \r 1 adequate.  An adequate number of trials
were conducted reflecting the proposed use patterns in the appropriate
geographic regions, and the appropriate commodities were collected at
the proposed PHIs.  Samples were analyzed using adequate analytical
methods, and the sample storage intervals are supported by the available
storage stability data.  The available artichoke data will support a
tolerance for residues of 1.4 ppm on artichoke, globe; the peach and
plum data will support a tolerance for residues of 0.70 ppm on fruit,
stone, group 12; and the winter squash data will support a tolerance for
residues of 0.20 ppm on squash, winter, pumpkin, and gourd, edible.  The
petitioner did not submit any crop field trial data for pumpkin or
edible gourd, but based on the Reviewers Guide and Summary of HED
ChemSAC Approvals for Amending Commodity Definitions (B. Schneider,
06/14/2002) those specific commodities are included in the definition
for winter squash.

860.1520 Processed Food and Feed

There are no processed commodities associated with the proposed uses. 
Therefore, no processing studies are required to support these
petitions.

860.1850/1900 Confined and Field Accumulation in Rotational Crops

Adequate confined and field rotational crop studies are not available
(D276835, G. Kramer, 03/26/2003).  Crops having quinoxyfen tolerances
may be replanted at any time.  Rotation to all other crop tolerances
should be prohibited.

860.1550 Proposed Tolerances

HED has concluded that the tolerance expression for plant commodities
should include only parent quinoxyfen.  Permanent tolerances are
established for residues of quinoxyfen per se [40 CFR §180. 588 (a)]
in/on cherries (0.30 ppm); grapes (0.60 ppm); hop, dried cones (3.0
ppm); lettuce, head (7.0 ppm); lettuce, leaf (19 ppm); pepper, bell
(0.35 ppm); pepper, nonbell (1.7 ppm); strawberry (0.90 ppm); and melon
subgroup 9A (0.08 ppm).  Time-limited tolerances are established for
residues of quinoxyfen per se [40 CFR §180. 588 (b)] in/on pumpkin
(0.30 ppm); and squash, winter (0.30 ppm).  The tolerances proposed by
the registrant in the current petition are listed below in Table 5,
along with HED’s recommended tolerance levels.   SEQ CHAPTER \h \r 1 
The appropriate tolerance levels were calculated using the Agency’s
Guidelines for Setting Pesticide Tolerances Based on Field Trial Data,
and the methodology formulated by the NAFTA MRL/Tolerance Harmonization
Workgroup for calculating statistically-based pesticide tolerances for
plant commodities based on field trial residue data (Attachment 2).  
SEQ CHAPTER \h \r 1 

The available artichoke data will support a tolerance for residues of
1.4 ppm on artichoke, globe; the winter squash data will support a
tolerance for residues of 0.20 ppm on squash, winter, pumpkin, and
gourd, edible; the peach and plum data will support a tolerance for
residues of 0.70 ppm fruit, stone, group 12.

  SEQ CHAPTER \h \r 1 

Table 5.  Tolerance Summary for Quinoxyfen.

Crop Commodity	Proposed Tolerance (ppm)	Recommended Tolerance (ppm)
Comments

  SEQ CHAPTER \h \r 1 (correct commodity definition)

Fruit, stone, group 12	0.70	0.70

	Squash, winter	0.20	0.20

	Pumpkin	0.20	0.20

	Gourd, edible	0.20	0.20

	Artichoke, globe	1.4	1.4

	Cherry, sweet	Revoke	Revoke	Included in Fruit, stone, group 12

Cherry, tart	Revoke	Revoke	Included in Fruit, stone, group 12

International Tolerances

CODEX MRLs exist for quinoxyfen on cherry, tart and cherry, sweet at 0.4
ppm; and Canadian MRLs exist for cherry, sweet and cherry, tart at 0.3
ppm.  While these differ from the fruit, stone, group 12 tolerance
proposed herein, residues above both the CODEX and Canadian MRLs were
observed in the submitted field trial data. No Mexican MRLs have been
established for quinoxyfen.  An International Residue Limits Status
(IRLS) sheet is attached.

Attachments

Attachment 1.	International Residue Limits Status sheet

Attachment 2.	  SEQ CHAPTER \h \r 1 Tolerance-Assessment   SEQ CHAPTER
\h \r 1 Calculations

RDI:  F. Fort  (10/30/2008), RRB2 Chemists (11/04/2008)

DBWilbur:S-10833:(703)347-8894:7509PC:RRB2

Attachment 1.

INTERNATIONAL RESIDUE LIMIT STATUS

Chemical Name:

5,7-dichloro-4-(4-

fluorophenoxy)quinoline	

Common Name:

Quinoxyfen	

X Proposed tolerance

   Reevaluated tolerance

   Other	

Date:

10/30/2008

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#8E7325

DP#s:  354559

Other Identifier:

Residue definition: N/A	

Reviewer/Branch:  DB Wilbur

	

Residue definition:  parent only

Crop (s)	

MRL (mg/kg)	

Crop(s)	

Tolerance (ppm)

	

	

Artichoke	1.4

	

	Squash, winter	0.20

	

	Pumpkin	0.20

	

	Gourd, edible	0.20

Cherry, sweet	0.4	Fruit, stone, group 12	0.70

Chery, tart	0.4

	

Limits for Canada	

Limits for Mexico

 No Limits

 No Limits for the crops requested	

X No Limits

 No Limits for the crops requested

Residue definition: 5,7-dichloro-4-(4-

fluorophenoxy)quinoline

	

Residue definition: N/A

Crop(s)	

MRL (mg/kg)	

Crop(s)	

MRL (mg/kg)

Cherry, sweet

	0.3	

	

Cherry, tart	0.3

	

	

Notes/Special Instructions:  

Steve Funk, 10/20/2008

Rev. 1998

Attachment 2.	  SEQ CHAPTER \h \r 1 Tolerance-Assessment   SEQ CHAPTER
\h \r 1 Calculations

Artichoke

Regulator:	EPA

Chemical:	Quinoxyfen

Crop:	Artichoke

PHI:	0

App. Rate:	0.519 - 0.536 lb ai/acre

	Submitter:	DBW

	Residues	LN(Residues)	Z-scores

	1.090	0.09	1.28

	0.950	-0.05	0.64

	0.940	-0.06	0.20

	0.630	-0.46	-1.28

	0.870	-0.14	-0.20

	0.830	-0.19	-0.64

 	Regulator:	EPA	 

 	Chemical:	Quinoxyfen	 

 	Crop:	Artichoke	 

 	PHI:	0	 

 	App. Rate:	0.519 - 0.536 lb ai/acre

 	Submitter:	DBW	 

 	 

 

 	n:	6	 

 	min:	0.63	 

 	max:	1.09	 

 	median:	0.91	 

 	average:	0.89	 

 	 	 	 

 	95th Percentile	99th Percentile	99.9th Percentile

EU Method I

Normal	1.2	1.3	1.4

	(1.5)	(1.7)	(--)

95/99 Rule	1.2	1.4	1.6

	(1.8)	(2.5)	(--)

EU Method II

Distribution-Free	 	2.0	 

	 	 	 

Mean+3SD	 	1.4	 

	 	 	 

UCLMedian95th	 	8.0	 

	 

 

Approximate Shapiro-Francia Normality Test Statistic	 	0.9044	 

	 	p-value > 0.05 : Do not reject lognormality assumption	 

	 	 	 

Winter Squash

Regulator:	EPA

Chemical:	Quinoxyfen

Crop:	Winter Squash

PHI:	3-4 days

App. Rate:	0.519 - 0.536 lb ai/acre

	Submitter:	DBW

	Residues	LN(Residues)	Z-scores

	0.039	-3.24	-0.66

	0.054	-2.92	-0.12

	0.031	-3.47	-1.00

	0.027	-3.61	-1.55

	0.044	-3.12	-0.38

	0.067	-2.70	0.38

	0.082	-2.50	0.66

	0.064	-2.75	0.12

	0.106	-2.24	1.00

	0.106	-2.24	1.55

 	Regulator:	EPA	 

 	Chemical:	Quinoxyfen	 

 	Crop:	Winter Squash	 

 	PHI:	3-4 days	 

 	App. Rate:	0.519 - 0.536 lb ai/acre

 	Submitter:	DBW	 

 	 

 

 	n:	10	 

 	min:	0.03	 

 	max:	0.11	 

 	median:	0.06	 

 	average:	0.06	 

 	 	 	 

 	95th Percentile	99th Percentile	99.9th Percentile

EU Method I

Normal	0.15	0.15	0.20

	(0.15)	(0.20)	(--)

95/99 Rule	0.15	0.20	0.25

	(0.25)	(0.40)	(--)

EU Method II

Distribution-Free	 	0.20	 

	 	 	 

Mean+3SD	 	0.15	 

	 	 	 

UCLMedian95th	 	0.40	 

	 

 

Approximate Shapiro-Francia Normality Test Statistic	 	0.9711	 

	 	p-value > 0.05 : Do not reject lognormality assumption	 

	 	 	 

Peach (Stone Fruit Group 12)

Regulator:	EPA

Chemical:	Quinoxyfen

Crop:	Peach

PHI:	7

App. Rate:	0.516 - 0.522 lb ai/acre

	Submitter:	DBW

	Residues	LN(Residues)	Z-scores

	0.063	-2.76	-1.45

	0.080	-2.53	-0.67

	0.078	-2.55	-0.81

	0.057	-2.86	-1.91

	0.160	-1.83	0.41

	0.091	-2.40	-0.29

	0.095	-2.35	-0.06

	0.076	-2.58	-0.98

	0.210	-1.56	0.67

	0.140	-1.97	0.29

	0.094	-2.36	-0.17

	0.130	-2.04	0.17

	0.200	-1.61	0.53

	0.220	-1.51	0.81

	0.090	-2.41	-0.41

	0.083	-2.49	-0.53

	0.120	-2.12	0.06

	0.069	-2.67	-1.19

	0.410	-0.89	0.98

	0.540	-0.62	1.45

	0.550	-0.60	1.91

	0.430	-0.84	1.19

 	Regulator:	EPA	 

 	Chemical:	Quinoxyfen	 

 	Crop:	Peach	 

 	PHI:	7	 

 	App. Rate:	0.516 - 0.522 lb ai/acre

 	Submitter:	DBW	 

 	 

 

 	n:	22	 

 	min:	0.06	 

 	max:	0.55	 

 	median:	0.11	 

 	average:	0.18	 

 	 	 	 

 	95th Percentile	99th Percentile	99.9th Percentile

EU Method I

Normal	0.45	0.60	0.70

	(0.60)	(0.70)	(--)

95/99 Rule	0.45	0.80	1.3

	(0.80)	(1.4)	(--)

EU Method II

Distribution-Free	 	0.45	 

	 	 	 

Mean+3SD	 	0.70	 

	 	 	 

UCLMedian95th	 	0.60	 

	 

 

Approximate Shapiro-Francia Normality Test Statistic	 	0.8991	 

	 	0.05 >= p-value > 0.01 : Reject lognormality assumption	 

	 	 	 

Plum

Regulator:	EPA

Chemical:	Quinoxyfen

Crop:	Plum

PHI:	7

App. Rate:	0.516 - 0.522 lb ai/acre

	Submitter:	DBW

	Residues	LN(Residues)	Z-scores

	0.004	-5.42	-1.64

	0.006	-5.18	-1.11

	0.007	-5.02	-0.79

	0.007	-4.91	-0.54

	0.008	-4.82	-0.31

	0.009	-4.74	-0.10

	0.009	-4.67	0.10

	0.087	-2.44	1.11

	0.095	-2.35	1.64

	0.011	-4.51	0.31

	0.012	-4.42	0.54

	0.013	-4.34	0.79

 	Regulator:	EPA	 

 	Chemical:	Quinoxyfen	 

 	Crop:	Plum	 

 	PHI:	7	 

 	App. Rate:	0.516 - 0.522 lb ai/acre

 	Submitter:	DBW	 

 	 

 

 	n:	12	 

 	min:	0.00	 

 	max:	0.10	 

 	median:	0.01	 

 	average:	0.02	 

 	 	 	 

 	95th Percentile	99th Percentile	99.9th Percentile

EU Method I

Normal	0.08	0.10	0.15

	(0.15)	(0.15)	(--)

95/99 Rule	0.07	0.15	0.30

	(0.20)	(0.50)	(--)

EU Method II

Distribution-Free	 	0.03	 

	 	 	 

Mean+3SD	 	0.15	 

	 	 	 

UCLMedian95th	 	0.06	 

	 

 

Approximate Shapiro-Francia Normality Test Statistic	 	0.7606	 

	 	p-value <= 0.01: Reject lognormality assumption	 

	 	 	 

		Summary of Analytical Chemistry and Residue Data	

Quinoxyfen (055459)	DP#s: 354559

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