Document ID: EPA-HQ-OPP-2006-0178-0007
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2007-06-22T04:00Z

SEQ CHAPTER \h \r 1 Primary Evaluator	

	Date:  

	Christine L. Olinger, Chemist, RRB1

	

  SEQ CHAPTER \h \r 1 This DER was originally prepared under contract by
Dynamac Corporation (2275 Research Boulevard, Suite 300; Rockville, MD
20850; submitted 07/18/2006).  The DER has been reviewed by the Health
Effects Division (HED) and revised to reflect current Office of
Pesticide Programs (OPP) policies.

STUDY REPORTS:

46531301  Pensyl J.W. (1993) Magnitude of the Residues of Lactofen and
its Metabolites in Green Peppers.  Lab Project number:  1714/91/1027. 
Unpublished study prepared by Valent U.S.A. Corporation, 239 p.  

46597201  Pensyl J.W. (1996) Magnitude of the Residue of Lactofen and
its Metabolites in Tomatoes.  Project number:  VP-11576.  Unpublished
study prepared by Valent U.S.A. Corporation, 241 p.  

46597202  Kowalsky J. (2003) Magnitude of the Residues of Lactofen on
Peppers.  Lab Project Number: V-03-25304.  Unpublished study prepared by
Valent U.S.A. Corporation, 84 p.

46597203  Kowalsky J. (2003) Magnitude of the Residues of Lactofen on
Tomatoes.  Lab Project Number: V-03-25291.  Unpublished study prepared
by Valent U.S.A. Corporation, 75 p.

EXECUTIVE SUMMARY:

Valent U.S.A. Corporation has submitted field trial data for lactofen on
the representative crops, pepper and tomato, of the fruiting vegetables
group, crop group 8.  A total of three pepper trials were conducted in
Zone 3 (FL) during the 1991 (one bell pepper trial) and 2003 (one bell
and one nonbell pepper trial) growing seasons.  A total of four tomato
field trials were conducted in Zone 3 (FL) during the 1990 (three
trials) and 2003 (one trial) growing seasons.  We note that both tomato
varieties used in the crop field trials produce medium to large fruits.

For the pepper field trials, the 2 lb/gal emulsifiable concentrate (EC)
formulation of lactofen was applied at each test location as one
pre-transplant and one postemergence directed soil application to row
middles at 0.49-0.51 lb ai/A/application for a total seasonal
application rate of 0.98-1.1 lb ai/A.  Shielded spray equipment was used
in the 2003 trials.  The first applications were made one or 12 days
prior to transplanting, and the second applications were made at 46- to
67-day retreatment intervals.  First applications were made in spray
volumes of 31-33 gal/A, and second applications were made in spray
volumes of 55-59 gal/A; nonionic surfactant (NIS) or crop oil
concentrate (COC) adjuvants were added to the spray mixtures for second
applications.  Mature peppers were harvested 30 days following the
second application.

For the tomato field trials, the 2 lb/gal EC formulation of lactofen was
applied at each test location as one pre- or early post-transplant
application and one to two postemergence directed soil applications to
row middles at ~0.5 lb ai/A/application for total seasonal application
rates of 0.96 lb ai/A (2003 field trial) or 1.5 lb ai/A (1990 trials);
the 2003 trial included a treatment plot with two applications at an
exaggerated rate of ~2.5 lb ai/A/application for a total seasonal
application rate of ~5 lb ai/A.  Shielded spray equipment was used for
all trials.  The first applications were made one or 12 days prior to
transplanting or 5 days post-transplant; second applications were made
at 30- to 37-day retreatment intervals; and third applications were made
at 14- to 16-day retreatment intervals.  First applications were made in
spray volumes of 31-34 gal/A, and second and third applications were
made in spray volumes of 55-60 gal/A; NIS or COC adjuvants were added to
the spray mixtures for all applications, except the pre-transplant
applications at the 2003 trial.  Mature tomatoes were harvested 28-30
days following the last application.

Soil characteristics data were not provided for two pepper field trials
and one tomato trial; however, these data are not required at this time
because most of the relevant information is available from a reliable
public source.  For future submissions, the petitioner is advised that
soil characteristics data must be provided for field trials reflecting
applications to soil.  

The maximum storage intervals of samples from harvest to analysis were
60 days for peppers and 56 days for tomatoes.  A freezer storage
stability study was conducted in conjunction with the 1990 magnitude of
the residue study on tomatoes.  Residues of lactofen and metabolites
PPG-847, PPG-947, and PPG-2597 appeared to be relatively stable in/on
tomatoes stored frozen for up to 68 days.  Residues of PPG-1576 were
found to decline in tomatoes, to ~60% of original value after 68 days of
storage.  These data are adequate to support the storage intervals and
conditions of samples from the fruiting vegetable crop field trials. 
Because residues of PPG-1576 were found to be below the LOD in/on all
tomato samples and below the LOQ in/on all pepper samples that were
analyzed for residues of PPG-1576, no correction for potential decline
during storage is needed.

Samples from the pepper and tomato field trials were analyzed using
established gas chromatography with electron capture detection (GC/ECD)
enforcement methods or modified versions of established enforcement
methods.  Pepper samples from the 1991 trial and tomato samples from the
1990 trials were analyzed for residues of lactofen and its metabolites
PPG-1576, PPG-2597, PPG-847, and PPG-947 using method RM-28 (Method B of
PAM Vol. II).  The method was performed essentially as written for
analysis of tomatoes, but was modified significantly for analysis of
peppers.  Samples of peppers and tomatoes from the 2003 trials were
analyzed for residues of lactofen per se using method RM-28D-2 (rev.
8/12/03); method RM-28D is listed in the U.S. EPA Index of Pesticide
Analytical Methods.  The validated limits of quantitation (LOQs) were
0.01 ppm for peppers from the 1991 trial, and 0.02 ppm for samples from
all other trials.  The methods are adequate for data collection based on
acceptable method validation and concurrent recovery data.  

Residues of lactofen and metabolites were each below the LOQ (<0.01 ppm
for the 1991 pepper field trials and <0.02 ppm for remaining pepper and
tomato field trials) in/on all samples of pepper and tomato harvested
~30 days following a single pre- or early post-transplant and one to two
postemergence directed soil applications to row middles at ~0.5 lb
ai/A/application for total seasonal application rates of ~1-1.5 lb ai/A.
 

No residue decline data were included in the submission; however,
because residues were below the LOQ in/on all samples, these data are
not required.

STUDY/WAIVER ACCEPTABILITY/DEFICIENCIES/CLARIFICATIONS:

Under the conditions and parameters used in the study, the field trial
residue data are classified as scientifically acceptable.  The
acceptability of this study for regulatory purposes is addressed in the
forthcoming U.S. EPA Residue Chemistry Summary Document DP Barcode
D333151.

COMPLIANCE:

Signed and dated Good Laboratory Practice (GLP), Quality Assurance and
Data Confidentiality statements were provided.    SEQ CHAPTER \h \r 1 No
deviations from regulatory requirements were reported which would have
an impact on the validity of the study.

A.	BACKGROUND INFORMATION

Lactofen [1-(carboethoxy)ethyl-5-[2-chloro-4-(trifluoromethyl)
phenoxy]-2-nitrobenzoate] is a selective contact, diphenyl ether
herbicide (Group 14) that is structurally related to acifluorfen and is
classified as a threshold carcinogen by EPA.  Lactofen, formulated as an
EC, is currently registered by Valent U.S.A. Corporation for
preemergence and/or postemergence use on soybeans, snap beans, and
cotton for the control of broadleaf weeds, such as nightshades, morning
glories, pigweed, and ragweed.  Tolerances are currently established for
residues of the herbicide lactofen
(1-(carboethoxy)ethyl-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitroben
zoate) on snap bean, cotton seed, peanut and soybean seed at 0.01 ppm
and on cotton gin products at 0.02 ppm [40 CFR §180.432(a)]. 

Valent has submitted a petition (PP# 5E6930) proposing the use of
Cobra® herbicide (EPA Reg. No. 59639-34) on fruiting vegetables.

TABLE A.1.	Lactofen Nomenclature.

Chemical structure	

Common name	Lactofen

Company experimental name	PPG-844

IUPAC name
1-(carboethoxy)ethyl-5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenz
oate

CAS name	2-ethoxy-1-methyl-2-oxoethyl
5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate

CAS registry number	77501-63-4

End-use product (EP)	2 lb/gal EC (Cobra ® Herbicide; EPA Reg. No.
59639-34) 

Chemical structure of acifluorfen (PPG-847)	

5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid

Chemical structure of desethyl lactofen (PPG-947) 	

1-(carboxy)ethyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoate

Chemical structure of amino lactofen (PPG-1576)	

1-(carboethoxy)ethyl
5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-aminobenzoate

Chemical structure of N-formyl lactofen (PPG-2597)	

1-(carboethoxy)ethyl
5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-formamidobenzoate

Chemical structure of PPG-1530; Isomer A (internal standard)	

1-(carboethoxy)ethyl
5-[2-chloro-4-(trifluoromethyl)phenoxy]-6-nitrobenzoate

TABLE A.2.	Physicochemical Properties of Lactofen

Parameter	Value	Reference

Melting point/range	>250°C	444470031

pH	7.2 (on Pure Active Ingredient, 1% solution) at 25°C	444470031

Density (specific gravity)	1.34 at 24°C	444470031

Water solubility	0.97 ppm at 25°C

0.945 ± 0.131 ppm (column elution method at 20 ± 1 °C)	444470031

444609022

Solvent solubility		       g/100 g at 23 °C

kerosene                   15.6

2-ethyl-1-hexanol     18.4

N-decanol                 10.1

lactic acid                   0.9

Lactofen is miscible at all proportions with the following solvents at
-18°C or higher:

DMSO, monochlorotoluene, dipropylene glycol dibenzoate, isophorone,
cyclohexanone, mixed xylene, ethylene dichloride, acetone, DMF, amyl
acetate, methyl isobutyl ketone.	444470031

Vapor pressure	3.69 ± 1.73 x 10-5 Pa (2.8 x 10-7 mm Hg)	444609012

Dissociation constant, pKa	Not required	D241826, 1/16/98, H. Podall

Octanol/water partition coefficient, Log(KOW)	1 x 105 at ambient
temperature, estimated value	444609032

UV/visible absorption spectrum	In Review 3	444470033

1 RD Memorandum, D241826, 1/16/98, H. Podall.

2 RD Memorandum D242241, 2/5/98, S. Mathur.

3 D332587, C. Olinger, In Review. 

B.	EXPERIMENTAL DESIGN

A total of three pepper trials were conducted in Zone 3 (FL) during the
1991 (one bell pepper trial) and 2003 (one bell and one nonbell pepper
trial) growing seasons.  A total of four tomato field trials were
conducted in Zone 3 (FL) during the 1990 (three trials) and 2003 (one
trial) growing seasons.

The study use pattern is detailed in Table B.1.2.  For the pepper field
trials, the 2 lb/gal EC formulation of lactofen was applied at each test
location as one pre-transplant and one postemergence directed soil
application to row middles at 0.49-0.51 lb ai/A/application for a total
seasonal application rate of 0.98-1.1 lb ai/A; shielded spray equipment
was used in the 2003 trials.  The first applications were made one or 12
days prior to transplanting, and the second applications were made at
46- to 67-day retreatment intervals.  First applications were made in
spray volumes of 31-33 gal/A, and second applications were made in spray
volumes of 55-59 gal/A; NIS or COC adjuvants were added to the spray
mixtures for second applications.  Mature peppers were harvested 30 days
following the second application.

For the tomato field trials, the 2 lb/gal EC formulation of lactofen was
applied at each test location as one pre- or early post-transplant
application and one to two postemergence directed soil applications to
row middles at ~0.5 lb ai/A/application for total seasonal application
rates of 0.96 lb ai/A (2003 field trial) or 1.5 lb ai/A (1990 trials);
the 2003 trial included a treatment plot with two applications at an
exaggerated rate of ~2.5 lb ai/A/application for a total seasonal
application rate of ~5 lb ai/A.  Shielded spray equipment was used for
all trials.  The first applications were made one or 12 days prior to
transplanting or 5 days post-transplant; second applications were made
at 30- to 37-day retreatment intervals; and third applications were made
at 14- to 16-day retreatment intervals.  First applications were made in
spray volumes of 31-34 gal/A, and second and third applications were
made in spray volumes of 55-60 gal/A; NIS or COC adjuvants were added to
the spray mixtures for all applications, except the pre-transplant
applications at the 2003 trial.  Mature tomatoes were harvested 28-30
days following the last application.

Trial site conditions are presented in Table B.1.1.  The crop varieties
grown are identified in Table C.3.  Soil characteristics data were not
provided for the trials conducted at Citra, FL.  These data would
generally be required because the submitted crop field trials reflect
directed application to the soil.  However, these data will not be
required at this time because most of the relevant information is
available from a reliable public source.  For future submissions, the
petitioner is advised that soil characteristics data must be provided
for field trials reflecting applications to soil.  We note that both
tomato varieties used in the crop field trials produce medium to large
fruits.

The petitioner provided acceptable daily, monthly, and/or historical
weather data (temperature and rainfall) for all field trial sites, as
well as descriptions of cultural procedures; maintenance chemicals and
fertilizers used at each site were identified.  Irrigation was used at
all sites.  The weather was reported to be normal for all field trials
except the 1990 tomato field trials, where 10” of rain were received
due to a tropical storm 3 days before the third application. The
petitioner stated that this event was not believed to have significantly
affected the results of the study. 

B.1.	Study Site Information

TABLE B.1.1.	Trial Site Conditions.

Trial Identification (City, State; Year; Trial ID #); MRID	Soil
characteristics 1

	Type	%OM	pH	CEC

(meq/g)

Pepper

Myakka City, FL 1991; 46531301	Fine sand	0.8	7.0	4.2

Citra, FL 2003; V25304-A; 46597202	NR [Fine sand]	NR [1%]	NR [6.4]	NR

Citra, FL 2003; V25304-B; 46597202	NR [Fine sand]	NR [1%]	NR [6.4]	NR

Tomato

Immokalee, FL, 1990; T-7554; 46597203	Sand	1.8	6.8	3.8

Bradenton, FL, 1990; T-7555; 46597203	Sand	1.6	6.7	5.1

Bradenton, FL, 1990; T-7556; 46597203	Sand	1.9	7.0	5.3

Citra, FL, 2003; V-25291-A; 45697201	NR [Fine sand]	NR [1%]	NR [6.4]	NR

1 NR = Not reported; these data are required because the submitted crop
field trials reflect directed application to the soil.  The [bracketed]
information was obtained by the study reviewer from several University
of FL Internet listings.

TABLE B.1.2.	Study Use Pattern.

Location

(City, State; Year)

Trial ID	EP1	Application	Tank Mix/ Adjuvants 4

 Method; Timing	Volume

(GPA)2	 Rate 

(lb ai/A)	RTI3 (days)	Total Rate (lb ai/A)

	Pepper

Myakka City, FL 1991; 46531301	2.0 lb/gal EC	1. Directed to soil; one
day before transplant	30 	0.5 	--	1.0	--

2. Directed to soil; crown fruit 2” diameter; plant height 13”	60
0.5	46

NIS

Citra, FL 2003; V25304-A; 46597202	2.0 lb/gal EC	1. Directed to soil,
shielded; 12 days before transplant	31 	0.50 	--	1.1	--

2.  Directed to soil, shielded; fruiting, small to med-small fruit	59
0.51	67

COC

Citra, FL 2003; V25304-B; 46597202	2.0 lb/gal EC	1. Directed to soil,
shielded; 12 days before transplant	31 	0.49 	--	0.98	--

2.  Directed to soil, shielded; fruiting, small to med-small fruit	56
0.49	67

COC

Tomato

Immokalee, FL, 1990; T-7554; 46597203	2.0 lb/gal EC	1. Directed to soil;
shielded; one day before transplant	34 	0.5	--	1.5	NIS

2. Directed to soil; shielded; early bloom; plant height 20-26”	60	0.5
35

NIS

3. Directed to soil; shielded; early fruit-set; plant height 28-34”	60
0.5	14

NIS

Bradenton, FL, 1990; 

T-7555; 46597203	2.0 lb/gal EC	1. Directed to soil; shielded; 5 days
post-transplant	32	0.5	--	1.5	NIS

2. Directed to soil; shielded; 1st  bloom cluster open; plant height
20”	52	0.5	37

NIS

3. Directed to soil; shielded; 1st hand fruit 2” diam.; plant height
28”	55	0.5	16

NIS

Bradenton, FL, 1990; 

T-7556; 46597203	2.0 lb/gal EC	1. Directed to soil; shielded; 5 days
post-transplant	32	0.5	--	1.5	NIS

2. Directed to soil; shielded; 1st  bloom cluster open; plant height
24”	52	0.5	37

NIS

3. Directed to soil; shielded; 1st hand fruit 1 ¾ -2” diam.; plant
height 28-30”	55	0.5	16

NIS

Citra, FL, 2003; V-25291-A; 45697201	2.0 lb/gal EC	1. Directed to soil,
shielded; 12 days before transplant	30.5	0.49	--	0.96	--

2.  Directed to soil, shielded; small green fruit; plant height 2-3’
54.6	0.47	30

COC

	2.0 lb/gal EC	1. Directed to soil, shielded; 12 days before transplant
31.3	2.50	--	4.9	--

2.  Directed to soil, shielded; small green fruit; plant height 2-3’
56.3	2.40	30

COC

1 EP = End-use Product

2 GPA = Gallons per acre 

3 RTI = Retreatment Interval

4 NIS = Nonionic surfactant; COC = crop oil concentrate

TABLE B.1.3.	Trial Numbers and Geographical Locations.

NAFTA Growing Zones	Pepper	Tomato

	Submitted

	Requested 1	Submitted

	Requested 1

Canada	U.S.

Canada	U.S.

1

1

1A

2

	1 (bell)

	1

3	3 (2 bell and 1 non-bell)

1 (bell)	4

2

4

5

	1 (bell)

	1

5A

5B

6

	1 (bell)

	7

7A

8

9

10

	2 (bell)

	7

11

12

13

14

15

16

17

18

19

20

21

Total	3

6 bell + 3 nonbell 2	4

12

  SEQ CHAPTER \h \r 1 1  As required by OPPTS 860.1500, Tables 2 and 5,
for peppers and tomatoes as representative members of the fruiting
vegetables crop group.  The number of trials for each represents a 25%
reduction due to the crop being a representative commodity used to
obtain a crop group tolerance, or due to the pesticidal use resulting in
no quantifiable residues.

2  Specific regions are not recommended for non-bell peppers, because
only 3 trials are required; however, according to Table 6 of OPPTS
860.1500, U.S. production of non-bell peppers occurs in Zones 2 (4%), 3
(3%), 5 (4%), 8 (50%), 9 (15%), and 10 (18%). 

B.2.	Sample Handling and Preparation

Single control and duplicate treated samples of peppers and tomatoes
were harvested from each site at commercial maturity, 28-30 days
following the second or third application.  For the 1990 tomato field
trials, the petitioner reported that mature green tomatoes were
harvested according to commercial agricultural practices.  Pepper
samples were placed in frozen storage at the field sites within 30
minutes of harvest.  Tomato samples from the 2003 trial and green
tomatoes from the 1990 trials were placed in frozen storage at the field
sites within 3.5 hours of harvest; additional samples from the
Bradenton, FL sites were placed in a ripening room (temperature
unspecified) immediately following harvest, and were held there for 6
days until they had been degreened; degreened tomatoes were then placed
in frozen storage until shipment.  Samples were shipped frozen within
1-15 days of harvest to the analytical laboratories:  the Bioanalytical
Laboratory; Oregon State University (Corvallis, OR) for the 1991 pepper
trial; Chevron Technical Center (Richmond, CA) for the 1990 tomato
trials; or Valent Technical Center (Dublin CA) for the 2003 pepper and
tomato trials.  Samples were stored frozen (~-20 °C) at the analytical
laboratories until preparation for analysis via chopping or macerating
with dry ice.  

B.3.	Analytical Methodology

Samples from the pepper and tomato field trials were analyzed using
established GC/ECD enforcement methods or modified versions of
established enforcement methods.  Pepper samples from the 1991 trial and
tomato samples from the 1990 trials were analyzed for residues of
lactofen and its metabolites PPG-1576, PPG-2597, PPG-847, and PPG-947
using method RM-28 (Method B of PAM Vol. II).  The method was performed
essentially as written for analysis of tomatoes, but was modified
significantly for analysis of peppers.  Modifications to the analytical
method for peppers included:  (1) conducting the acetonitrile
(ACN):hexane partitioning earlier in the procedure; (2) separation of
the acid metabolites (PPG-847 and PPG-947) from lactofen and the ester
metabolites (PPG-1576 and PPG-2597) for analysis; and (3) addition of a
two-column clean-up procedure for the acid metabolites.  Samples of
peppers and tomatoes from the 2003 trials were analyzed for residues of
lactofen per se using method RM-28D-2 (rev. 8/12/03); method RM-28D is
listed in the U.S. EPA Index of Pesticide Analytical Methods.  

Using the modified version of method RM-28, samples from the 1991 pepper
field trial were extracted 2x with ACN containing 1% triethylamine
(TEA):hexane (2:1, v:v) and filtered, and the extracts were combined. 
Following phase separation, the ACN phase was extracted with two
additional aliquots of hexane; all hexane phases were discarded.  The
ACN extract was combined with 5% NaCl solution and partitioned 3x with
hexane.  The resulting extracts were combined to yield an aqueous ACN
extract and a hexane extract.  The hexane extracts, containing lactofen
and the ester metabolites, were concentrated and applied to a silica gel
column for clean-up.  Residues were eluted with dichloromethane
(DCM):hexane (70:30, v:v), and the eluate was concentrated, combined
with an internal standard mixture of CGA-1530 (lactofen Isomer A) and
CGA-1827 (standard was not identified), and reserved for GC analysis. 
The aqueous ACN extract, containing the acid metabolites, was acidified
with 6 N HCl and extracted 3x with toluene.  The combined toluene
extracts were applied to a basic alumina column, and residues were
eluted with 1% sodium bicarbonate solution.  The eluate was acidified
with 6 N HCl and extracted 3x with DCM.  Diazomethane was added to the
combined DCM extracts to methylate the acid metabolites, and the mixture
was reduced to dryness and re-dissolved in benzene, then applied to a
second alumina column.  Residues were eluted with benzene, concentrated,
combined with the internal standard mixture, and reserved for GC
analysis.  Lactofen and the ester metabolites were determined using an
SPB-5 column, and the acid metabolites were determined using a DB-1701
column.  The validated LOQ was 0.01 ppm (lowest limit of method
validation; LLMV), and the reported limit of detection (LOD) was 0.005
ppm for lactofen and each metabolite.

Using method RM-28, samples from the 1990 tomato field trials were
extracted 2x with ACN containing 1% TEA and filtered.  The resulting
extract was evaporated to dryness, re-dissolved in 5% NaCl solution,
then partitioned with DCM (3x).  The resulting DCM phases were combined,
reduced to dryness, dissolved in ACN, and combined with diazomethane to
methylate the acid metabolites.  The methylated extract was dissolved in
DCM:hexane (70:30, v:v), and applied to a silica gel column.  Residues
were eluted with DCM:hexane (70:30, v:v), and the eluate was
concentrated, combined with an internal standard of CGA-1530 (lactofen
Isomer A) in toluene, and reserved for GC analysis using a DB-5 or
DB-1701 column.  We note that the method included modified instructions
for analysis of residues of  PPG1576 alone to improve recoveries; the
petitioner did not indicate whether these procedures were followed.  The
validated LOQ (LLMV) was 0.02 ppm, and the LOD was 0.01 ppm for lactofen
and each metabolite.

Using method RM-28D-2, samples of peppers and tomatoes from the 2003
trials were extracted 2x with ethanol and filtered.  The combined
extracts were reduced by rotary evaporation and sonicated with ACN
saturated with hexane, followed by 5% NaCl solution, and hexane.  The
resulting ACN:water phase was re-extracted 2x with hexane, and the
hexane extracts were combined with the original hexane phase.  The
combined hexane phase was evaporated to dryness and redissolved in
toluene:hexane (1:2, v:v), then applied to a silica gel column for
clean-up.  Residues were eluted with hexane:diethyl ether (60:40, v:v),
and the eluate was evaporated to dryness and dissolved in toluene for
analysis by GC/ECD on a DB-17 column.  The validated LOQ was 0.02 ppm
(LLMV), and the reported LOD was 0.01 ppm for lactofen in both matrices.

C.	RESULTS AND DISCUSSION

Sample storage conditions and intervals are summarized in Table C.2.1. 
The maximum storage intervals of samples from harvest to analysis were
60 days for peppers and 56 days for tomatoes.  A freezer storage
stability study was conducted in conjunction with the 1990 magnitude of
the residue study on tomatoes.  Untreated samples of tomato were
fortified with lactofen, PPG-847, PPG-947, PPG-1576, and PPG-2597 at 0.1
ppm each, and stored frozen.  Stored samples were analyzed at 0-day and
following frozen storage for 32 and 68 days.  Residues of lactofen, and
all metabolites except PPG-1576 appeared to be relatively stable (Table
C.2.2) in/on tomatoes stored frozen for up to 68 days.  Residues of
PPG-1576 were found to decline in tomatoes, to ~60% of original value
after 68 days of storage.  These data are adequate to support the
storage intervals and conditions of samples from the fruiting vegetable
crop field trials.  Because residues of PPG-1576 were found to be below
the LOD in/on all tomato samples and below the LOQ in/on all pepper
samples that were analyzed for residues of PPG-1576, no correction for
potential decline during storage is needed.

Method validation and concurrent recovery data are presented in Table
C.1.  Samples from the pepper and tomato field trials were analyzed
using established GC/ECD enforcement methods or modified versions of
established enforcement methods.  Pepper samples from the 1991 trial and
tomato samples from the 1990 trials were analyzed for residues of
lactofen and its metabolites PPG-1576, PPG-2597, PPG-847, and PPG-947
using method RM-28 (Method B of PAM Vol. II).  The method was performed
essentially as written for analysis of tomatoes, but was modified
significantly for analysis of peppers.  Samples of peppers and tomatoes
from the 2003 trials were analyzed for residues of lactofen per se using
method RM-28D-2 (rev. 8/12/03); method RM-28D is listed in the U.S. EPA
Index of Pesticide Analytical Methods.  The validated LOQ and LOD were
0.01 ppm and 0.005 ppm, respectively, for peppers from the 1991 trial,
and 0.02 ppm and 0.01 ppm, respectively, for samples from all other
trials.  The methods are adequate for data collection based on
acceptable method validation and concurrent recovery data.  Method
validation was conducted for method RM-28D-2 using tomato during method
development; recoveries were 103-104% for tomato fortified at 0.02 ppm. 
Concurrent recoveries of lactofen ranged 90-93% for pepper fortified at
0.01 ppm and 93-117% for pepper and tomato fortified at 0.02 ppm. 
Recoveries of the lactofen metabolites ranged 73-114% from samples of
pepper fortified at 0.01 ppm and tomato fortified at 0.02 ppm.  Apparent
residues of lactofen and metabolites were nondetectable in/on all
samples of untreated pepper and tomato.

The results of the fruiting vegetable crop field trials are reported in
Table C.3.  A summary of the residue data is presented in Table C.4. 
Residues of lactofen and metabolites were each below the LOQ (<0.01 ppm
for the 1991 pepper field trials and <0.02 ppm for remaining pepper and
tomato field trials) in/on all samples of pepper and tomato harvested
~30 days following a single pre- or early post-transplant and one to two
postemergence directed soil applications to row middles at ~0.5 lb
ai/A/application for total seasonal application rates of ~1-1.5 lb ai/A.
 

No residue decline data were included in the submission; however,
because residues were below the LOQ in/on all samples, these data are
not required.  

TABLE C.1.	Summary of Method Validation and Concurrent Recoveries of
Lactofen Residues from Pepper and Tomato.

Matrix 

(Method)	Analyte	Spike level

 (ppm)	Sample size

 (n)	Recoveries

 (%)	Mean  ( std dev

(%) 1

Method validation

Tomato 2

(RM-28D-2; 

DB-17 column)	Lactofen	0.02	3	103, 105, 105	104 ± 1

Tomato

(RM-28D-2;

DB-5 column)	Lactofen	0.02	3	101, 103, 104	103 ± 2

Concurrent recovery

Pepper

(RM-28)	Lactofen	0.01	2	90, 93	92

	PPG-847	0.01	1	97	--

	PPG-947	0.01	1	107	--

	PPG-1576	0.01	2	81, 86	84

	PPG-2597	0.01	2	100, 114	107

Pepper

(RM-28D-2)	Lactofen	0.02	2	103, 117	110

0.1	2	98, 108	103

Tomato 2 

(RM-28)	Lactofen	0.02	5	93, 93, 95, 96, 100	95 ± 3

	PPG-847	0.02	5	89, 99, 104, 106, 113 	102 ± 9

	PPG-947	0.02	5	97, 98, 102, 104, 105 	101 ± 4

	PPG-1576	0.02	5	73, 75, 75, 78, 86	77 ± 5

	PPG-2597	0.02	5	76, 81, 87, 89, 93 	85 ± 7

Tomato

(RM-28D-2)	Lactofen	0.02	2	108, 112	110

0.10	1	87	--

1  Standard deviations were only calculated for samples sizes ≥3.

2  Including green and degreened tomatoes.

TABLE C.2.	Summary of Storage Conditions.  

Matrix 	Storage Temperature

 (°C)	Actual Storage Duration 1

(days) 	Interval of Demonstrated Storage Stability

Pepper	-20	39-60	Residues of lactofen and metabolites were relatively
stable in/on tomato stored frozen for up to 68 days

Tomato	-20	22-56

	1  Interval from harvest to analysis; samples were analyzed within 2-9
days of extraction.

TABLE C.2.2	Stability of Lactofen Residues in Frozen Tomatoes.

Analyte	Spike Level

(ppm)	Storage interval (days)	Freshly Fortified Recovery (%)	Stored
Sample Residues (%) [Average]	Average Corrected Stored Recovery (%)1

Lactofen	0.1	0	101	97, 102 [100]	99

32	96	91, 95 [93]	97

68	101	79, 86 [83]	82

PPG-847	0.1	0	109	119, 121 [120]	110

32	110	103, 109 [106]	96

68	121	97, 101 [99]	82

PPG-947	0.1	0	101	99, 100 [100]	99

32	94	91, 98 [95]	95

68	107	89, 97 [93]	87

PPG-1576	0.1	0	55	55, 57 [56]	102

32	92	69, 73 [72]	78

68	86	48, 52 [50]	58

PPG-2597	0.1	0	94	88, 94 [91]	97

32	76	70, 73 [72] 	95

68	96	85, 89 [87]	91

1   Residues were corrected for recovery from freshly fortified samples.

TABLE C.3.	Residue Data from Pepper and Tomato Field Trials with
Lactofen 

Trial ID

(City, State; Year); MRID	Zone	Variety	Commodity or Matrix	Total Rate

(lb ai/A)	PHI  (days)	Residues  (ppm)1

Lactofen	PPG-847	PPG-947	PPG-1576	PPG-2597

Pepper

Myakka City, FL 1991; 46531301	3	Memphis	Bell pepper	1.0	30	<0.01, <0.01
<0.01, <0.01	<0.01, <0.01	<0.01, <0.01	<0.01, <0.01

Citra, FL 2003; V25304-A; 46597202	3	Camelot	Bell pepper	1.1	30	ND, ND
NA	NA	NA	NA

Citra, FL 2003; V25304-B; 46597202	3	Hot Beauty	Nonbell Pepper	0.98	30
ND, ND	NA	NA	NA	NA

Tomato

Immokalee, FL, 1990; T-7554; 46597203 	3	Solar Set	Tomato (green) 	1.5
28	ND, ND	ND, ND	ND, ND	ND, ND 	ND, ND

Bradenton, FL, 1990;

T-7555; 46597203	3	Solar Set	Tomato (green) 	1.5	30	ND, ND	ND, ND	ND, ND
ND, ND 	ND, ND

	Tomato (degreened) 

	ND, ND	ND, ND	ND, ND	ND, ND 	ND, ND

Bradenton, FL, 1990;

T-7556; 46597203	3	Sunny	Tomato (green) 	1.5	30	ND, ND	ND, ND	ND, ND	ND,
ND 	ND, ND

	Tomato (degreened) 

	ND, ND	ND, ND	ND, ND	ND, ND 	ND, ND

Citra, FL, 2003;

V-25291-A; 46597203	3	FLA47	Tomato	0.96	30	ND, ND	NA	NA	NA	NA

4.9	30	ND, ND	NA	NA	NA	NA

1 ND = Nondetectable.  NA = Not analyzed.  The reported LOQs were 0.01
ppm for the 1991 pepper field trial, and 0.02 ppm for all other field
trials, and the reported LODs were 0.003 ppm for the 1991 pepper field
trial, and 0.01 ppm for all other trials; we note that values were
reported by the petitioner as <0.01 ppm for all samples analyzed.  

TABLE C.4.	Summary of Residue Data from Pepper Field Trials with
Lactofen.

Commodity	Total Applic. Rate

 (lb ai/A)	PHI (days)	Residue Levels

 (ppm)1

	n	Min.	Max.	HAFT2	Median

(STMdR)	Mean

(STMR)	Std. Dev.

Lactofen

Pepper	0.98-1.1	30	6	<0.01	<0.02	<0.02	<0.01	<0.01	0.0

Tomato	0.96	28-30	2	<0.02	<0.02	<0.02	<0.01	<0.01	0.0

	1.5	30	10	<0.02	<0.02	<0.02	<0.01	<0.01	0.0

	4.9	30	2	<0.02	<0.02	<0.02	<0.01	<0.01	0.0

1  The reported LOQs were 0.01 ppm for the 1991 pepper field trial, and
0.02 ppm for all other field trials.  For calculation of the median,
mean, and standard deviation, a value of 0.01 ppm (½ the LOQ for the
majority of residue results) was used for samples with residues <LOQ.

2  HAFT = Highest Average Field Trial. 

D.	CONCLUSION

The submitted field trial data are adequate and reflect a single pre- or
early post-transplant and one to two postemergence directed soil
applications to row middles at ~0.5 lb ai/A/application for a total
seasonal application rate of ~1-1.5 lb ai/A.  Residues were below the
LOQ in/on samples of mature peppers and tomatoes harvested ~30 days
following the last application.  Acceptable methods were used for
quantitation of residues in/on peppers and tomatoes, and the data are
supported by acceptable storage stability data.

E.	REFERENCES

DP Barcode:	RD D241826

Subject:	TGAI Product Chemistry Review/Action:  345.  Reg. File Symbol
No.:  59639-94.  Chemical:  Lactofen—76.7% pure.  Company:  Valent
U.S.A. Corp. 

From:		H. Podall

To:		S. Stanton

Date:		1/16/98

MRIDs:	44447001-44447003

DP Barcode:	RD D242241

Subject:	Product Chemistry Review of TGAI.  Reg./File Symbol No.: 
59639-94.  Product Name:  Lactofen Technical. 

From:		S. Mathur

To:		J. Miller

Date:		2/5/98

MRIDs:	44460901-44460903

F.	DOCUMENT TRACKING

RDI: COlinger (10/16/06)

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	Crop Field Trial/Residue Decline – Fruiting Vegetables, Crop Group 8

DP Barcode D333151/MRID Nos. 46531301 and 46597201-46597203	Page   PAGE 
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