Document ID: EPA-HQ-OPP-2009-0239-0005
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-06-29T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

OFFICE OF           

PREVENTION, PESTICIDES

AND TOXIC SUBSTANCES

Date:		October 21, 2008

Subject:  	Metolachlor:  Metolachlor Residue Chemistry Data For Crop
Subgroup

6-b Commodities; and a Field Accumulation in Rotational Crops Study with
Metolachlor Using Oats and Wheat.

PC Code: 108800	DP Barcodes:   D336373/D348268

MRID Nos.:  47015301, 47312501	Registration No.: Numerous

Petition No.: N/A 	Regulatory Action: Section 3 

Assessment Type:  N/A                    	Reregistration Case No.: 0001

TXR No.: None	CAS No.:  51218-45-2

Decision #s:  348979/388477

	

From:		Dennis McNeilly, Chemist

RAB2, Health Effects Division, (7509P)

Through:  	    Douglas Dotson, Ph.D., Chemist

		RAB2, Health Effects Division (7509P)

			And

Michael Doherty, Ph.D., Senior Chemist

		RAB2, Health Effects Division (7509P)	

TO:		Eugene Wilson/Joanne Miller, RM 23

Herbicide Branch, Registration Division (7505P)

				and

		Michael Goodis, RM53

Special Review and Reregistration Division (7508P)

The Metolachlor Task Force sponsored field trial data for metolachlor on
Crop 

Subgroup 6-b commodities (MRID 47015301) to fulfill a data gap
identified in the Metolachlor RED and TRED (TRED for Metolachlor and
S-Metolachlor, D292881, S. Kinard, 8/15/03.  Five field trials were
conducted in the United States using succulent beans (four trials) and
succulent peas (one trial) during the 2005 growing season.  The field
trials with beans encompassed EPA Growing Zones 1, 2, and 3, while the
field trial with peas was in Zone 1.  Treated plots received one
pre-plant incorporated (PPI) application at a nominal application rate
of 1.33 lb ai/A for coarse soils or 1.67 lb ai/A for medium soils. 
Pre-harvest intervals (PHIs) ranged from 51 to 69 days for peas, beans,
and forage, and from 54 to 76 days for hay. 

The Metolachlor Task Force also submitted a field accumulation in
rotational crops study using metolachlor (MRID 47312501) in response to
a 2004 data call-in (DCI).  Two rotational crop studies were conducted
using oat and wheat as the rotational crops during the 2006-2007 growing
season in CA and GA.  At both sites, the first application was made at a
target rate of 1.33 lb ai/A/application and the second was made at a
rate of 1.67 lb ai/A/ application, with a 41- to 95-day retreatment
interval, for a  total seasonal rate of 3.0 lb ai/A.

Executive Summary

Metolachlor is a selective, chloroacetanilide herbicide that is applied
to a variety of crops as a preplant, preplant-incorporated (PPI),
pre-emergence, or post-emergence-directed application (Note: there is no
post-emergence application for Crop Group 6 commodities), primarily for
the control of grass weeds.  Metolachlor is registered for use on a wide
variety of crops including: corn, cotton, grasses grown for seed, legume
vegetables, peanuts, potatoes, safflower, sorghum, sunflower, and
tomatoes.

The nature of metolachlor residues in plants and animals is understood. 
For metolachlor (and S-metolachlor, an enriched isomer) the residues of
concern in plants and animals include the parent compound (both R and
S-enantiomers) and its metabolites, determined as the derivatives
CGA-37913 and CGA-49751 (for both tolerance and risk assessment
purposes).  Following recommendations made in the revised Tolerance
Reassessment Eligibility Decision (TRED) for Metolachlor and
S-Metolachlor (D292881, S. Kinard, 8/15/03), tolerances for metolachlor
and S-metolachlor have been separated.  Permanent tolerances for
combined (free and bound) S-metolachlor residues have been established
in/on plant commodities ranging from 0.1 ppm in/on a variety of crops to
20 ppm in/on peanut hay [40 CFR §180.368(a)(2)].  (Note:  The
enforcement methods in PAM Vol. II both determine residues of
metolachlor and its metabolitres as either CGA-37913 or CGA-49751
following acid hydrolysis.)  Permanent tolerances for indirect or
inadvertent residues of metolachlor have also been established for
non-grass animal feeds (group 18), and the forage, hay, grain and straw
of small cereal grains (barley, buckwheat, oats, rice, rye and wheat). 
Tolerances for rotational crops range from 0.1 ppm in/on various cereal
grains to 1.0 ppm in/on non-grass animal feeds and hay of barley, oats
and wheat [40 CFR §180.368(d)].

Adequate methodology is available for enforcing the current tolerances. 
The Pesticide Analytical Manual (PAM, Vol. II) lists a GC/NPD method
(Methods I) for determining residues in/on plants and a GC/MSD method
(Method II) for determining residues in livestock commodities.  These
methods determine residues of metolachlor and its metabolites as either
CGA-37913 or CGA-49751 following acid hydrolysis.  Adequate data are
available on the recovery of metolachlor through multi-residue method
testing protocols.  The FDA PESTDATA database indicates that metolachlor
is completely recovered through Method 302, PAM Vol. I (3rd ed., revised
10/97).

S  SEQ CHAPTER \h \r 1 torage stability data are available for other
plant commodities that could translate to support the sample storage
conditions and durations from the submitted field trials.  Data are
available indicating that CGA-37913 is stable at ≤10°C for at least
24 months in corn (grain and forage), peanuts, potatoes (tubers, wet
peel and flakes), soybean (hulls and meal), and tomatoes, for at least
29 months in cottonseed oil, and for at least 37 months in cottonseed
and corn oil.  The derivative CGA-49751 is also stable at ≤10°C for
at least 24 months in corn (grain and forage), peanuts, potatoes
(tubers, wet peel and flakes), soybean (hulls and meal), and tomatoes,
and for at least 37 months in cottonseed and cottonseed oil (D282931, S.
Kinard, 4/22/2002).  

Storage stability data relating to this specific study (i.e., Crop
Subgroup 6-b field trial data) have not been submitted to demonstrate
the stability of metolachlor and its metabolites in Crop Subgroup 6-b,
matrices; however, a storage stability study was reported to be underway
at the time of the study report publication.  This study should be
submitted.

The submitted Crop Subgroup 6-b, legume vegetable field trial data are
not adequate by themselves to support the use of metolachlor on
succulent shelled peas and beans (Crop Subgroup 6-b).  However, when
related data from Crop Subgroups 6-a and 6-c and other existing Crop
Subgroup 6-b data are evaluated together with these data; the overall
data are adequate for tolerance reassessment of Crop Subgroup 6-b
commodities.

An adequate confined rotational crop study is available (D341704, D.
Soderberg, 11/28/2007).  That study shows that total radioactive
residues (TRR) for all commodities except wheat grain are significantly
greater than 0.1 ppm at all plant back intervals.  TRR for wheat grain
are 0.5 ppm at a 30-day plantback interval (PBI), but are only about
0.05 ppm for all longer intervals.  Analyses for metolachlor, per se,
show, at most, only very trace findings in any crops where they have
been done.  The residues of concern in rotated crops are the same as in
the primary crops, metolachlor and its metabolites determined as
CGA-37913 and CGA-49751. 

The submitted wheat and oat rotational crop field trials are adequate
and support the minimum PBI of 4.5 months for barley, oats, rye and
wheat.    

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

No major deficiencies were noted in the submitted field trials or
rotational crop field trials that would preclude reassessing tolerances
for metolachlor residues in/on Crop Subgroup 6-b, legume vegetables
(except soybean), or for rotational small cereal grains.  However, a few
minor deficiencies must be resolved as a condition of registration (see
below).

A revised human health risk assessment is not required for metolachlor
for the following reasons:  1) The tolerance for Crop Subgroup 6-b
commodities was reassessed at its current value of 0.3 ppm. 2) Only very
minor changes have been made to crop rotation tolerances with the
reassessed or calculated tolerance being lower for both significant feed
items, i.e., grain and forage.  The reassessed tolerance for straw was
slightly higher and would not affect secondary residues in livestock
commodities. 3)  There have been no changes in the toxicology database
since the last human health risk assessment was conducted which was
associated with the RED/TRED (TRED for Metolachlor and S-Metolachlor,
D292881, S. Kinard, 8/15/03).  For these reasons, the exposure and risk
estimates given in the previous risk assessment do not increase for the
general U.S. population or any population subgroup.

HED recommends establishing a reassessed permanent tolerance for the
combined residues of  metolachlor and its metabolites in/on the
succulent, shelled peas and beans (Crop Subgroup 6-b) at 0.3 ppm.  The
use it supports is a single broadcast soil or PPI application at
planting or as a single broadcast foliar application.  The data support
maximum single and seasonal use rates of 1.33 lb ai/A for coarse soils
or 1.67 lb ai/A for medium soils, and a 50-day PHI.  The residue data
indicate that the tolerance of 0.3 ppm for Crop Subgroup 6-b is
adequate. 

HED recommends for the revision of, and/or the establishment of,
indirect or inadvertent tolerances (40CFR 180.368(d)), as specified in
Table 8 under the heading “reassessed tolerances.”  The registrant
should submit a petition to revise these tolerances.  End-use labels for
metolachlor should reflect the 4.5 month (135-day) plant back interval
restriction, as reflected in the submitted study (as well as the maximum
seasonal application rate of 3.0 lbs ai/A).

Additional Data Needs. 

1)  Storage stability data relating to this specific study (i.e., Crop
Subroup 6-b field trial data) have not been submitted to demonstrate the
stability of metolachlor and its metabolites in the Crop Subgroup 6-b
matrices.  A storage stability study was reported to be underway at the
time of the study report publication.  The maximum storage interval from
harvest to extraction was 250 days for forage, 216 days for hay, and 167
days for pods.  The study reported to be underway at the time of the
study report publication should be submitted.

Background

  SEQ CHAPTER \h \r 1 Metolachlor
[2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)
acetamide] is a selective, chloroacetanilide herbicide that is applied
to a variety of crops as a preplant, PPI, preemergence, or
post-emergence-directed application, primarily for the control of grass
weeds.  Metolachlor is used on a wide variety of crops.  An extensive
review of metolachlor uses and tolerances was conducted in the Revised
TRED for Metolachlor and S-Metolachlor (D292881, S. Kinard, 8/15/03).

In response to deficiencies noted in these earlier reviews, the
Metolochlor Task Force has provided the following data:  1) field trial
data supporting the use of metolachlor on succulent shelled peas and
beans, Crop Subgroup 6-b; and 2) field accumulation in rotational crop
studies on representative small grains (wheat and oats).

The chemical structure and nomenclature of metolachlor and its
derivatives CGA-49751 and CGA-37913, and the physicochemical properties
of the technical grade of metolachlor are presented in Tables 1 and 2.  

TABLE 1.	Test Compound Nomenclature.

Compound	

Common name	Metolachlor

Company experimental name	Not applicable

IUPAC name
2-chloro-N-(6-ethyl-o-tolyl)-N-[(1RS)-2-methoxy-1-methylethyl]acetamide

or

)-2-chloro-6′-ethyl-N-(2-methoxy-1-methylethyl)acet-o-toluidide

CAS name
2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide

CAS registry number	51218-45-2

End-use product (EP)	Stalwart® Herbicide (EPA Reg. No. 60063-34; 8
lb/gal EC)

Compound	

Common name	CGA-49751

Chemical name	4-(2-ethyl-6-methylphenyl)-2-hydroxy-5-methyl-3-morpholine

CAS registry number	61520-54-5

Compound	

Common name	CGA-37913

Chemical name	2-[(2-ethyl-6-methylphenyl)amino]-1-propanol

CAS registry number	61520-53-4



TABLE 2.	Physicochemical Properties of Technical Grade Metolachlor

Parameter	Value	Reference1

Physical state (color)	Liquid (pale yellow to light brown)	TRED Product
Chemistry Chapter (D274330)

Boiling point	100OC at 0.001 mm mercury.	RED

pH	7-9 @ 25OC (1% aqueous dispersion)	TRED Product Chemistry Chapter
(D274330)

Density	1.117 g/mL at 20OC	TRED Product Chemistry Chapter (D274330)

Water solubility	0.48 g/L @ 25OC	TRED Product Chemistry Chapter
(D274330)

Solvent solubility	Miscible in xylene, toluene,

ethylene dichloride, and cyclohexanone.	RED

Vapor pressure	2.8 x 10-5 mm Hg @ 25OC	TRED Product Chemistry Chapter
(D274330)

Octanol/water partition coefficient, Log(KOW)	3.05 @ 25OC	TRED Product
Chemistry Chapter (D274330)

860.1200  Directions for Use

Three end-use product labels (EPA Reg. Nos.:  19713-539, 56077-69, and
60063-17) were submitted with the two studies for HED review.  The
submitted field trial data reflect the use of a single application of
metolachlor at total application rates of 1.3-1.7 lb ai/A on pod crops
(beans and peas) grown in the United States.

The end use labels have the following restrictions:  Do not apply more
than 3 pints/A (3 lbs ai/A) of this product during one crop year.  One
of the labels has the following restriction:  “FOR CA ONLY:  Broadcast
this product to the soil and thoroughly incorporate with a disk or
similar implement set to till to 4 to 6 inches deep.  For more thorough
incorporation, till the soil in two different directions
(cross-till).”

860.1300 Nature of the Residue - Plants

The qualitative nature of metolachlor residues in plants is adequately
understood based upon the adequate corn, potato, and soybean metabolism
studies.  The metabolism of metolachlor involves conjugation with
glutathione, breakage of this bond to form the mercaptan, conjugation of
the mercaptan with glucuronic acid, O-demethylation of the methyl ether,
and conjugation of the resultant alcohol with a neutral sugar.  A minor
pathway may involve sugar conjugation of metolachlor directly to the
corresponding oxo-compounds.  Residues of concern in plants (for both
tolerance and risk assessment purposes) include metolachlor and its
metabolites, determined as the derivatives CGA-37913 and CGA-49751.

The Agency has also reviewed plant metabolism data on S-metolachlor from
field tests on soybeans and corn, in vitro tests on corn seedlings, and
greenhouse tests on seedlings of corn, sorghum, soybeans and peanuts
(D279110, S. Kinard, 8/15/03).

860.1300 Nature of the Residue - Livestock

Adequate studies are available depicting the metabolism of metolachlor
in ruminants and poultry.  Metolachlor is rapidly metabolized and almost
totally eliminated in the urine and feces of ruminants (goats),
non-ruminants (rats), and poultry.  Metolachlor per se was not detected
in any of the excreta or tissues.  As in plants, metolachlor residues of
concern in animal commodities include metolachlor and its metabolites,
determined as the derivatives CGA-37913 and CGA-49751.

The Agency has also reviewed animal metabolism data on S-metolachlor
(D292881, S. Kinard, 8/15/03).  Data from a goat metabolism study
indicated that S-metolachlor was readily absorbed and extensively
metabolized by goats via glutathione conjugation and/or oxidation
reactions.  Oxidized metabolites were also conjugated with glucuronic
acid.  Data from a poultry metabolism study indicated that S-metolachlor
was also extensively metabolized via O-demethylation and subsequent
glucuronic acid conjugation or oxidation to dihydroxy or carboxylic acid
metabolites that may also be conjugated with glucuronic acid.

860.1340 Residue Analytical Methods

Enforcement methods:    SEQ CHAPTER \h \r 1 Adequate methodology is
available for enforcing the established and recommended tolerances.  The
Pesticide Analytical Manual (PAM) Vol. II, Pesticide Regulation Section
180.368 lists a GC/NPD method (Methods I) for determining residues in/on
plants and a GC/MSD method (Method II) for determining residues in
animal commodities.  These methods determine residues of metolachlor and
its metabolites as either CGA-37913 or CGA-49751 following acid
hydrolysis.  

Data-gathering methods:  

Crop Subgroup 6-b, vegetables:  The samples were analyzed using EPL-BAS
method 478S01B-1, which is based on the analytical method appearing in
PAM II, Section 180.368.  Concurrent laboratory fortification samples
were prepared for each matrix from each site and run with each
analytical set.  Fortifications took place using metolachlor and each of
the two metabolites (CGA 37913 and CGA 49751).  Overall, individual
concurrent recoveries ranged from 67% to 118% for metolachlor, from 72%
to 106% for CGA 37913, and from 71% to 118% for CGA 49751.

Field Accumulation in Rotational Crops Study:  Samples of rotated oat
and wheat commodities were analyzed for residues of metolachlor and its
metabolites convertible to CGA-49751 and CGA-37913 using an LC/MS/MS
method.  The method was developed from the GC/NPD enforcement method for
plant commodities, Method I in the Pesticide Analytical Manual Vol. II.

Briefly, samples were subjected to acid hydrolysis in 6 N HCl at reflux
for 16 hours (or overnight) to convert residues of metolachlor and its
metabolites to either CGA-49751 or CGA-37913.  The hydrolysate was
isolated by filtration and diluted to volume with water.  An aliquot was
partitioned four times with dichloromethane (DCM).  The DCM phases,
which contain CGA-49751, were combined, and the aqueous phase, which
contains CGA-37913, was reserved.  The combined DCM  phases were
concentrated and partitioned with 5% sodium carbonate; the DCM phase was
concentrated to near dryness and reconstituted in acetonitrile: water
(1:1; v:v) for analysis.  For determination of CGA-37913, the reserved
aqueous phase was made basic with 50% NaOH and partitioned twice with
hexane.  The hexane phases were combined, evaporated to dryness, and
reconstituted in acetonitrile: water (1:1; v:v) for analysis.  The
extracts were analyzed by LC/MS/MS using a reverse phase column and a
gradient mobile phase of water and acetonitrile, each containing 0.5%
formic acid.  Residues were quantified using external standards.  The
registrant stated that, because matrix suppression of CGA-49751 was
observed, residues of this analyte were quantified using a calibration
curve of matrix-matched standards.

The reported limit of detection (LOD) was 0.002 ppm and the limit of
quantitation (LOQ) was 0.010 ppm for each analyte in oat and wheat
commodities, expressed as parent equivalents.  The LOQs expressed as
CGA-49751 and CGA-37913 equivalents were 0.0088 ppm and 0.0068 ppm,
respectively.   The method was validated prior to sample analysis using
untreated samples of rotated wheat commodities fortified with each
analyte at the LOQ, 10xLOQ, and 50xLOQ for forage, hay, and straw, and
the LOQ and 10xLOQ for wheat grain.  In addition, the method was
validated concurrently with sample analysis by fortifying samples of
each rotated crop commodity (except wheat forage) with each analyte at
the LOQ and 10xLOQ.

Conclusions.  Adequate enforcement methods are available for determining
residues in plant and animal commodities, and the LC/MS/MS methods used
for data collection in the submitted field trials and processing studies
were adequately validated in conjunction with the analysis of treated
samples from each of the studies.

860.1360 Multiresidue Methods

  SEQ CHAPTER \h \r 1 Adequate data are available on the recovery of
metolachlor through multiresidue method testing protocols.  The FDA
PESTDATA database indicates that metolachlor is completely recovered
through Method 302, PAM Vol. I (3rd ed., revised 10/97).

860.1380 Storage Stability

No storage stability data were submitted to support this specific study;
however, a study was reported to be underway.  S  SEQ CHAPTER \h \r 1
torage stability data are available for other plant and animal
commodities (D166637, B. Cropp-Kohlligian, 4/16/92).  For plant
commodities, the available data indicate that CGA-37913 is stable at
≤-10°C for at least 2 years in corn (grain and forage), peanut,
potato (tubers, wet peel and flakes), soybean (hulls and meal) and
tomatoes, for at least 29 months in cottonseed oil, and for at least 37
months in cottonseed and corn oil.  The derivative CGA-49751 is also
stable at ≤-10°C for at least 2 years in corn (grain, forage, and
oil), peanuts, potatoes (tubers, wet peel and flakes), soybeans (hulls
and meal) and tomatoes, and for at least 37 months in cottonseeds and
cottonseed oil.  In addition, storage stability studies conducted
concurrently with the asparagus, green onion, and carrot field trials
also indicate that both analytes are stable at -20°C for at least 14.1
months in asparagus, 24.3 months in carrots, and 21.7 months in green
onions.

Conclusions.  Storage stability data are available for translation to
support the storage durations and conditions for samples from the
submitted field trials and field accumulation study.  However; a storage
stability study was reported to be underway at the time of the study
report publication and should be submitted.  Samples from the Crop
Subgroup 6-b trials were stored frozen (-20(C) prior to analysis; the
maximum storage interval from harvest to extraction was 250 days (ca. 8
months) for forage, 216 days (ca. 7 months) for hay, and 167 days (ca. 5
months) for pods.

860.1500 Crop Field Trials

47015301.der.doc  Legume Vegetables, Succulent Shelled Beans and Peas
(Crop Subgroup 6-b)

HED’s review dated May 22, 2002 (D282931; S. Kinard) stated that: 
“Current tolerances on seed and pod vegetables (excluding soybean)
should be replaced by separate tolerances for the subgroup for the
edible-podded legume vegetables, dried shelled peas and beans (except
soybean), and succulent shelled peas and beans.”  That review further
stated that: “Adequate metolachlor residue data are available on
edible-podded and shelled dried peas and beans; however, data are
required on representative succulent shelled peas and beans.”  HED’s
review (D206103, David Miller, “Addendum to the RED”) of magnitude
of the residue data for legume vegetables cited three MRIDs as providing
data for this crop group:  00064182, 00128731, and 43295701.  MRID
00064182 contains Crop Group 6 data analyzed by Craven Labs and is not
being used in this analysis.

That review went on to state:  “Adequate residue data are available to
support uses on edible-podded and dried shelled legume vegetables
(excluding soybean).  Following a PPI application of metolachlor at 3.0
lb ai/A, combined residues were <0.08-0.44 ppm in/on edible podded peas
and beans and <0.08-<0.11 ppm in/on dried shelled peas and beans. 
However, adequate data are not available on shelled, succulent peas and
beans; these data are required”.

The Metolachlor Task Force sponsored a field trial study for metolachlor
on Crop Subgroup 6-b.  Five field trials were conducted in the United
States using succulent beans (four trials) and succulent peas (one
trial) during the 2005 growing season.  The trials with beans
encompassed Zones 1 (1 trial in Pennsylvania), 2 (1 trial in New Jersey,
1 trial in Georgia), and 3 (1 trial in Florida) and the trial with peas
encompassed Zone 1 (1 trial in New Jersey).  At each location, there was
one treated plot and one untreated plot. Treated plots received one
pre-plant incorporated application of Stalwart® Herbicide, an
emulsifiable concentrate (EC) formulation.  Each application was
performed at a nominal application rate of 1.33 lb ai/A for coarse soils
or 1.67 lb ai/A for medium soils. Adjuvants were not added to the spray
mixtures.  At each site, duplicate bean or pea samples, forage (green
vine) samples, and hay samples were collected from the control and
treated plots at normal harvest.  Prior to collection of the hay
samples, the hay was dried for 3 to 7 days in the field or under shelter
after harvest.  Pre-harvest intervals (PHIs) ranged from 51 to 69 days
for peas, or beans, and forage, and from 54 to 76 days for hay.

The analytical method used to analyze samples for this study was EPL-BAS
method 478S01B-1, which allows for quantification of metolachlor by
quantifying the amounts of the pair of acid hydrolyzed products CGA
37913 and CGA 49751.  Samples were analyzed using high performance
liquid chromatography with tandem mass selective detection (HPLC/MS/MS).
 The method is based on the analytical method appearing in PAM II,
Section 180.368. Method validation and concurrent laboratory fortified
samples were prepared using metolachlor and the metabolites CGA 37913
and CGA 49751.

Following a single application of metolachlor at a rate of 1.33 lb ai/A
to 1.67 lb ai/A, combined residues of CGA 37913 and CGA 49751 (total
metolachlor equivalents) ranged from below the LOQ to 0.089 ppm in
succulent beans and peas, 0.41 ppm to 2.3 ppm in bean and pea forage,
and 0.12 ppm to 0.49 ppm in bean and pea hay (Table 3).

Method validation samples were prepared and analyzed prior to the study
using sample matrices collected from Field Trial Site 1 (PA site). 
Additionally, concurrent laboratory fortification samples were prepared
for each matrix from each site and run with each analytical set. 
Fortifications took place using metolachlor and each of the two
metabolites (CGA 37913 and CGA 49751).  Both metabolite fortifications
were made to the same sample.  The metolachlor fortifications were made
to a different sample.  Target fortification levels for method
validation fortifications were the LOQ (0.01 ppm) and 10X LOQ (0.1 ppm)
and target fortification levels for the concurrent laboratory
fortifications ranged from 0.01 ppm to 0.1 ppm for pods, from 0.01 ppm
to 0.25 ppm for forage, and from 0.1 ppm to 3 ppm for hay.  Overall,
individual concurrent recoveries ranged from 67% to 118% for
metolachlor, from 72% to 106% for CGA 37913, and from 71% to 118% for
CGA 49751.

The following issues should be noted with regard to the fortification
results:

The study author corrected the recoveries for the residue detected in
control replicate A only.  The study report did not explain why control
replicate B was not used in the correction. 

Recoveries for metolachlor fortifications are based only on the
concentration of metabolite CGA 37913.  According to the Study Report,
it has been demonstrated that this metabolite is the only metabolite
found upon analysis of the hydrolysate.  Additionally, a correction
factor of 2 was applied to the recoveries from the metolachlor
fortifications because the study report states that only about a 50%
yield of CGA 37913 is expected after exhaustive hydrolysis of
metolachlor (EPA Recovery Study, PAM Volume II, Section 180.368).  A
correction factor was applied to metolachlor recoveries as a means of
normalizing the data to a 100% recovery basis. This was done to show
that metolachlor recoveries fall within an approximate range of 70-120%,
given the limitations of the reaction yield.  The metolachlor recovery
data were presented to demonstrate that the parent molecule hydrolysis
was consistent and were not used as a definitive means of evaluating the
validity of individual analytical sets.

TABLE 3.	Summary of Residue Data from Crop Field Trials with Metolachlor

Matrix	Total Applic. Rate

 [lb a.i./A]	Residue Levels

 (ppm)

N	Min.	Max.	HAFT	Median

(STMdR)	Mean

(STMR)	Std. Dev.

Total Metolachlor Residue (ppm)

Pod (Bean or Pea)	1.31 to 1.72	10	0.02 (<LOQ)	0.089	0.087	0.047	0.048
0.025

Hay

10	0.41	2.3	2.0	1.0	1.1	0.60

Forage

10	0.12	0.49	0.47	0.31	0.30	0.12

CGA 37913 Residue (Metolachlor equivalents, ppm)

Pod (Bean or Pea)	1.31 to 1.72	10	0.01 (<LOQ)	0.074	0.073	0.035	0.036
0.024

Hay

10	0.34	1.9	0.99	0.83	0.86	0.51

Forage

10	0.089	0.42	0.40	0.235	0.23	0.11

CGA 49751 Residue (Metolachlor equivalents, ppm)

Pod (Bean or Pea)	1.31 to 1.72	10	0.01 (<LOQ)	0.015	0.015	0.010 (<LOQ)
0.012	0.0022

Hay

10	0.067	0.42	0.34	0.23	0.23	0.11

Forage

10	0.013	0.098	0.47	0.071	0.064	0.027

HAFT = Highest Average Field Trial.

LOQ = 0.01 ppm for each analyte

Statistical calculations were performed using a value of LOQ when
residues were reported as <LOQ.

Conclusions:  The submitted field trial data reflect the use of a single
application of metolachlor (Stalwart® Herbicide formulation) at total
application rates of 1.3-1.7 lb ai/A on pod crops (beans and peas) grown
in the United States.  Four bean trials and one pea trial were
conducted; however, the EPA guidelines (860.1500, Table 3) recommend
conducting six bean trials and six pea trials for Crop Subgroup 6-b.

OTHER METLACHLOR RESIDUE DATA FOR CROP GROUP 6

In MRID 00128731 there are limited data for Crop Subgroup 6-b (lima
beans, pods and beans), for California and New York.  Five trials were
performed: 4 for beans and one for peas.  The pertinent residue data
from that study are as follows:

California    <0.08, <0.08.

New York   <0.08, <0.08, 0.16, 0.10, <0.08, <0.08, 0.15, 0.21.

In Table 4. residue data from MRID 43295701 for Crop Group 6 commodities
are summarized.  While there are no data in this study for Crop Subgroup
6-b, it does indicate that residues are higher for Crop Subgroup 6-a
commodities, and that a Crop Group tolerance is not appropriate. 
Therefore, the data will not be translated to Crop Subgroup 6-b.

    

Table 4.  Other Crop Group 6, Residue Data  (MRID 43295701). 

Test Location	PHI	Residue	Subgroup

Peas, dried

Washington	121	<0.08	6C

<0.08	“

Kansas	100	  0.04	“

  0.03	“

  0.04	“

<0.08	“

Pea, pods

Wisconsin	57	  0.05	6A

  0.06	“

California	52	  0.44	“

  0.39	“

Beans, dried

Washington	120	<0.08	6C

<0.08	 “

Colorado	102	<0.08	“

<0.08	“

Colorado

  0.03	6C

<0.08	“

California	119	  0.03	“

<0.08	“

Tennessee	65	  0.06	“

  0.04	“

Michigan	95	  0.04	“

  0.04	“

<0.08	“   Reanalysis

<0.08	“   Reanalysis

Bean, pods

Wisconsin	57	<0.08	6A

  0.03	“

Snap bean, pods

California	71	  0.24	6A

  0.20	“

  0.31	“  Reanalysis

  0.37	“  Reanalysis

Tennessee	60	  0.42	6A

  0.32	“

Michigan	63	  0.11	“

	63	  0.09	“

860.1650 Submittal of Analytical Reference Standards

The pesticide standards repository has recently depleted the supply of
metolachlor parent CAS# 51218-45-2 from both MANA and the Metolachlor
Task Force.  The repository has metolachlor oxanilic acid sodium salt
(CGA-51202) CAS# 152019-73-3, lot # 8112-7-27 from the Metolachlor Task
Force, but the certificate of analysis (COA) expired on 1/1/2008.    SEQ
CHAPTER \h \r 1  The reference standard (or a reassay and an updated
COA) should be sent to the Analytical Chemistry Lab, to the attention of
Theresa Cole at the following address:

	USEPA

	National Pesticide Standards Repository/Analytical Chemistry Branch/OPP

	701 Mapes Road

	Fort George G. Meade, MD  20755-5350

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

If new COAs are being submitted, they should be faxed to the repository
at 410-305-2999.860.1900 Field Accumulation in Rotational Crops

47312501.der.doc  Field Accumulation in Rotational Crops using Wheat and
Oats.

HED’s review dated Aug 15, 2003 (D255484, S. Kinard) stated that
additional data were required depicting the residues of metolachlor in
or on representative rotated cereal grains planted 4.5 months following
a single application of metolachlor at the maximum rate for corn.  Field
trials were to be conducted using wheat and oats.  Samples of forage,
hay, straw and grain should be collected from each test of wheat and
oats.  In addition, that review further stated that data for wheat and
oats would be translated to support similar tolerances for barley,
buckwheat, millet, rice, and rye.  It also stated that the established
tolerances on milo commodities should be revoked as residues in/on milo
commodities are covered by the current tolerances on sorghum.  In this
review, the wheat data are translated to support barley, buckwheat,
millet, rice, and rye because wheat commodities had the highest
calculated tolerances (see Appendix I).

Recently HED has reviewed a confined rotational crop study for
metolachlor using radish, lettuce, and wheat.  That review (D341704, D.
Soderberg, 11/28/07) concluded that metolachlor residues in or on wheat
grain were 0.54 ppm at 30 days, but otherwise declined to near 0.05 ppm
and remained at this level until 360 days.  In wheat forage the TRR was
1.1 ppm at 30 days and  declined to 0.76 ppm at 360 days; in wheat straw
the TRR dropped from 6.7 ppm at 30 days to 4.2 ppm at 360 days; TRR in
wheat hay ranged from 6.4 ppm at 30 days to 2.6 ppm at 360 days.  In
summary, the TRR exceeded 0.01 ppm for all the wheat commodities at 360
days. 

The current field accumulation study provides information on the level
of metolachlor residues in wheat and oat commodities (grain, forage,
straw and hay) planted 133-136 days after the last application of
metolachlor.

HED notes that the TRR and concentrations of parent metolachlor have now
been adequately determined at the maximum application rates, for all
plant back intervals tested; adequate characterization/identification of
general metabolism has been provided for all commodities; and adequate
characterization, in terms of the “enforcement method,” of the
residues in radish, lettuce and wheat grain exist at 120 days.  The
enforcement method involves hydrolysis of the many different metabolites
of metolachlor to produce two common moiety molecules.

Table 5.  Summary of Indirect or Inadvertent  Tolerances for Metolachlor
in or on Small Grains (40CFR 180.368(d)).

Commodity	Tolerance (pp)	Comments

Barley, grain	0.1

	Barley, hay	1.0

	Barley, straw	0.5

	Barley, forage	N/A	No tolerance listed.

Buckwheat, grain	0.1

	Buckwheat (hay, straw, forage)	N/A	No tolerances listed.

Oat, forage	0.5

	Oat, grain	0.1

	Oat, hay	1.0

	Oat, straw	0.5

	Rice, grain	0.1

	Rice, straw	0.5

	Rice, (forage, straw)	N/A	No tolerances listed.

Rye, grain	0.1

	Rye, straw	0.5

	Rye (forage, hay)	N/A	No tolerances listed.

Wheat, forage	0.5

	Wheat, grain	0.1

	Wheat, hay	1.0

	Wheat, straw	0.5

	

The Metolachlor Task Force submitted a field accumulation in rotational
crops study for wheat and oats (which can be translated to support
barley, buckwheat, millet, rice, and rye).  Two rotational crop studies
were conducted using oat and wheat during the 2006-2007 growing season
in California and Georgia.  Each trial consisted of one untreated plot,
one treated plot, and at both sites, a primary crop of dry beans was
planted.  At the CA site, the treated plot received one application of
an 8 lb/gal emulsifiable concentrate (EC) formulation approximately 3
hours prior to planting dry beans, followed by a second application five
days after the primary dry bean crop was harvested.  At the GA site, the
treated plot received one application of an 8 lb/gal EC formulation one
day after planting dry beans, followed by a second application one day
after the harvest of the primary dry bean crop.  At both sites, the
first application was made at a target rate of 1.33 lb ai/A/application
and the second was made at a rate of 1.67 lb ai/A/application, with a
41- to 95-day retreatment interval, for a  total seasonal rate of 3.0 lb
ai/A.  Applications were made using ground equipment in 20 gal/A spray
volumes without the use of an adjuvant.

At the CA site, the dry bean plants were cut at the soil surface and
then removed from the plot.  The method of destruction of the primary
crop at the GA site was not described.  Rotational crops of oat and
wheat were then planted at each site approximately 133-136 days after
the last application of metolachlor.  Samples of oat and wheat forage,
hay, grain, and straw were collected at appropriate crop growth stages,
98-101 days after planting (DAP) for forage, 126-136 DAP for hay, and
160-177 DAP for grain and straw.  

Samples were stored frozen (<0ºC) from harvest to extraction for
analysis for a maximum of 92 days (3.0 months) for forage, 97 days (3.2
months) for hay, 56 days (1.8 months) for grain, and 86 days (2.8
months) for straw; extracts were analyzed within 17 days of extraction. 
To support sample storage conditions and durations, the registrant
conducted a concurrent storage stability study with samples of fortified
wheat commodities.  These data are adequate to support the storage
conditions and durations of the rotational crop trials.

Samples of rotated oat and wheat commodities were analyzed using an
LC/MS/MS method which determines residues of metolachlor and its
metabolites convertible to CGA-49751 and CGA-37913 via acid hydrolysis. 
The LOQ expressed as metolachlor equivalents was 0.01 ppm for each
analyte, in each commodity.  The method was adequate for data collection
based on generally acceptable method validation and concurrent method
recovery data.  Concurrent method recoveries of CGA-49751 were low from
straw samples (average of 58%); because recoveries were consistent, the
method was deemed to be acceptable for data collection.  

TABLE 6.  Summary of Residue Data in Rotational Crops Following Primary
Treatment with Metolachlor.

Commodity	Applic. Rate

(lb ai/A)	PBI (days)	ppm, Metolachlor equivalents

	n	Min.	Max.	HAFT*	Median

(STMdR)	Mean

(STMR)	Std. Dev.

CGA-49751

Oat forage	3.0	133, 136	8	<0.01	0.065	0.040	0.019	0.025	0.020

Wheat forage

	8	<0.01	0.048	0.036	0.018	0.023	0.015

Oat hay	3.0	133, 136	8	<0.01	0.042	0.028	0.015	0.019	0.012

Wheat hay

	8	<0.01	0.085	0.076	0.038	0.043	0.035

Oat grain	3.0	133, 136	8	<0.01	<0.01	0.01	0.01	0.01	NA

Wheat grain

	8	<0.01	<0.01	0.01	0.01	0.01	NA

Oat straw	3.0	133, 136	8	<0.01	0.040	0.033	0.019	0.022	0.013

Wheat straw

	8	<0.01	0.106	0.097	0.049	0.054	0.047

* HAFT = Highest Average Field Trial

Following planting of rotational crops of oat and wheat 133 or 136 days
after the last of two applications of an 8 lb/gal EC formulation to the
soil at a total rate of 3.0 lb ai/A, total metolachlor residues in/on
rotated oat and wheat commodities were, respectively:  <0.02-0.191 and
<0.02-0.354 ppm in/on forage; <0.02-0.123 and <0.02-0.453 ppm in/on
wheat hay; <0.02-<0.030 and <0.02-<0.027 ppm in/on grain; and
<0.02-0.164 and <0.02-0.424 ppm in/on straw.  Residues of CGA-49751,
expressed as metolachlor equivalents, in/on rotated oat and wheat
commodities were, respectively:  <0.01-0.065 and <0.01-0.048 ppm in/on
forage; <0.01-0.042 and <0.01-0.085 ppm in/on wheat hay; <0.01 ppm in/on
grain; and <0.01-0.040 and <0.01-0.106 ppm in/on straw.  Residues of
CGA-37913, expressed as metolachlor equivalents, in/on rotated oat and
wheat commodities were, respectively:  <0.01-0.142 and <0.01-0.306 ppm
in/on forage; <0.01-0.089 and <0.01-0.368 ppm in/on wheat hay;
<0.01-0.020 and <0.01-0.017 ppm in/on grain, respectively; and
<0.01-0.128 and <0.01-0.318 ppm in/on straw.

International Residue Limits

 TC \l3 " 5.1.11	International Residue Limits  

Grains:

The following information was provided via email by Steve Funk, Ph.D.
(5/1/2008):

a)  Metolachlor is not a Codex chemical, i.e., no MRLs.  

b)  S-metolachlor (an enriched isomer of metolachlor) has MRLs in
Canada, but none for small grains.  (There is an MRL for corn grain, 0.1
ppm.).

c)  Metolachlor has MRLs in Mexico, but none for small grains.  (There
is an MRL for

     corn grain, 0.1 ppm)

Harmonization

The NAFTA Tolerance/MRL calculator indicates that a tolerance/MRL of
0.05 ppm is appropriate for rotational crop small grains; however, due
to the existing 0.1 ppm MRLs for grains in both Canada and Mexico, HED
recommends leaving the crop rotation grain tolerances at 0.1 ppm (Tables
5 and 7).

Crop Group 6 Commodities:

Canada has the following residue definition: 
2-chloro-N-(2-ethyl-6-methylphenyl)-N-[(1S)-2-methoxy-1-methylethyl)acet
amide and
2-chloro-N-(2-ethyl-6-methylphenyl)-N-[(1R)-2-methoxy-1-methylethyl)acet
amide including the metabolites
2-[(2-ethyl-6-methylphenyl)amino]-1-propanol and
4-(2-ethyl-6-methylphenyl)-2-hydroxy-5-methyl-3-morpholinone
2-chloro-N-(2-ethyl-6-methylphenyl)-N-[(1S)-2-methoxy-1-methylethyl)acet
amide and
2-chloro-N-(2-ethyl-6-methylphenyl)-N-[(1R)-2-methoxy-1-methylethyl)acet
amide, including the metabolites
2-[(2-ethyl-6-methylphenyl)amino]-1-propanol and
4-(2-ethyl-6-methylphenyl)-2-hydroxy-5-methyl-3-morpholinone.  Mexico
has the following residue definition:  S-metolachlor.

Selected MRLs (ppm) germane to this analysis for S-metolachlor are
provided in Table 7 (Note:  It does not include all s-metolachlor MRLs):

Table 7. 	Selected MRLs for S-Metolachlor.

Commodity	Canada	Mexico

Bean	--	15

Chick pea	--	15

Corn, grain	0.1	0.1

Dry bean	0.3	--

Lentil	--	15

Lima bean	0.3	--

Pea	0.3	--

Snap bean	0.3	--

Sorghum, grain	--	0.3

Soybean, grain	0.2	0.2

Harmonization

Canada currently has a tolerance of 0.3 ppm for S-metolachlor in peas
and snap beans. A higher United States tolerance could result in a trade
irritant for these crops exported from the United States to Canada.  In
addition, Canada has a tolerance of 0.3 ppm for S-metolachlor in dry
beans. A lower United States tolerance could result in a trade irritant
for these crops exported from Canada to the United States.  The residue
data support harmonization of these tolerances at 0.3 ppm tolerance. 

860.1550 Proposed Tolerances

Table 8.  Existing and Reassessed Indirect or Inadvertent Tolerances for
Metolachlor for Small Grains (40CFR 180.368(d)).

Commodity	Existing Tolerance

 (ppm)	Reassessed Tolerance (ppm)

Barley, forage	No tolerance listed.	0.50  (0.45 calculated)*

Barley, grain	0.1	0.1 (0.05 calculated)**

Barley, hay	1.0	0.8

Barley, straw	0.5	0.8

Buckwheat, forage	No tolerance listed.	0.50  (0.45 calculated)*

Buckwheat, grain	0.1	0.1 (0.05 calculated)**

Buckwheat, hay	No tolerance listed.	0.8

Buckwheat, straw	No tolerance listed.	0.8

Oat, forage	0.5	0.50  (0.45 calculated)*

Oat, grain	0.1	0.1 (0.05 calculated)**

Oat, hay	1.0	0.4

Oat, straw	0.5	0.4

Rice, grain	0.1	0.1 (0.05 calculated)**

Rice, forage	No tolerance listed.	No tolerance required

Rice, hay	No tolerance listed.	No tolerance required

Rice, straw	0.5	0.8

Rye, grain	0.1	0.1 (0.05 calculated)**

Rye, forage	0.5	0.50  (0.45 calculated)*

Rye, hay 	No tolerance listed.	0.8

Rye, straw	0.5	0.8

Wheat, grain	0.1	0.1 (0.05 calculated)**

Wheat, forage	0.5	0.50  (0.45 calculated)*

Wheat, hay	1.0	0.8

Wheat, straw	0.5	0.8

*  The existing oat, rye and wheat forages tolerances are 0.5 ppm and,
for harmonization purposes, HED recommends this level rather than the
calculated values of 0.45 ppm.

** The NAFTA calculator indicates a tolerance of 0.05 ppm is
appropriate; however, due to the existing 0.1 ppm MRLS for grains in
both Canada and Mexico, HED recommends leaving the crop rotation grain
tolerances at 0.1 ppm.

  SEQ CHAPTER \h \r 1 Attachment:

Appendix I - Tolerance Assessment CalculationsAppendix I.  Tolerance
Assessment Calculations.

Crop Subgroup 6-b:  The dataset used to evaluate Crop Subgroup 6-b
commodities  consisted of 10 field trials reflecting a single broadcast
soil or PPI application at planting or as a single broadcast foliar
application.  The data support maximum single and seasonal use rates of
1.33 lb ai/A for coarse soils or 1.67 lb ai/A for medium soils, and a
50-day PHI.  Other data from MRID 00128731 reflect 3.0 lb ai/A seasonal
use rate and PHI of 88-123 days.  The residue data indicate that the
existing tolerance of 0.3 ppm (the existing tolerance for pod
vegetables) for Crop Subgroup 6-b is adequate. 

Only 6 of the 20 field trial sample results were below the LOQ (LOQ =
0.08 ppm).  HED desired  a conservative estimate of the tolerance
because the dataset reflected less than the normal 12 field trials for
Crop Subgroup 6-b.  Therefore, maximum likelihood estimation (MLE)
procedures were not used to impute the censored values.  Instead the LOQ
value (0.08 ppm) was entered into the spreadsheet to calculate the
required tolerance for Crop Subgroup 6-b.

Rotational Crops:  The dataset used to evaluate rotational crop
tolerances for metolachlor on wheat and oat commodities consisted of
field trial data reflecting rotational crops treated with metolachlor. 
The first application was made at a target rate of 1.33 lb
ai/A/application and the second was made at a rate of 1.67 lb
ai/A/application, with a 41- to 95-day retreatment interval, for a 
total seasonal rate of 3.0 lb ai/A.  Samples of oat and wheat forage,
hay, grain, and straw were collected at appropriate crop growth stages,
98-101 days after planting (DAP) for forage, 126-136 DAP for hay, and
160-177 DAP for grain and straw.  

Although the Guidance for Setting Pesticide Tolerances Based on Field
Trial Data (SOP) specifies that the field trial application rates and
PHIs should be within 25% of the maximum label application rate and
minimum label PHI, respectively, the field trial data appear to
represent the use pattern the petitioner wishes to support.  The residue
values used to calculate the tolerance are provided in Tables II-2
through II-9.

Because 4 of 8 field trial sample results were below LOQ (LOQ = 0.08
ppm), maximum likelihood estimation (MLE) procedures were needed to
impute censored values.  These values are indicated with the * symbol. 
The data points were entered into the tolerance spreadsheet.  Visual
inspection of the lognormal probability plot indicates that the dataset
is reasonably lognormal.  The result from the approximate
Shapiro-Francia test statistic (Figure II-1) confirmed that the
assumption of lognormality should not be rejected. 

The field trial data for metolachlor represent a small dataset (i.e.,
less than 15 samples) and are reasonably lognormal.  Therefore, for all
wheat and oat commodities the upper bound estimate of the 95th
percentile based on the median residue value was compared to the minimum
of the 95% upper confidence limit on the 95th percentile and the point
estimate of the 99th percentile, and the minimum value was selected as
the tolerance value.

Figure II-1.  Data Summary Table for Metolachlor Residues on Crop
Subgroup 6-b Commodities.

	Regulator:	EPA

Chemical:	Metolachlor

Crop:	Crop Subgroup 6B

PHI:	51-69 Days

n:	20

min:	0.01

max:	0.21

median;	0.08

average:	0.08

95th Percentile	99th Percentile	99.9th Percentile

EU Method I

Normal	0.20	0.20	0.25

	(0.25)	(0.25)	(--)

EU Method I

Log Normal	0.25	0.45	0.90

	(0.50)	(1.1)	(--)

EU Method II

Distribution-Free

0.20

	California Method

Μ + 3σ

0.25

	UPLMedian95th

0.50

	Approximate Shapiro-Francia Normality Test Statistic	0.8941

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

	



Table II-1.	Metolachlor Residue Data for Crop Subgroup 6-b Commodities.

Metolachlor

Crop Subgroup,6B

51-69 Days

Residues

0.018

0.017

0.059

0.056

0.010

0.010

0.089

0.085

0.046

0.028

0.080

0.080

0.080

0.090

0.160

0.100

0.080

0.080

0.150

0.210

Figure II-2.  Data Summary Table for Metolachlor Residues on Oat
Forage.

Table II-2.	Metolachlor Residue Data for Oat Forage.

EPA

Metolachlor

Oats, forage

Rotational Crop

Residues

0.191

0.107

0.170

0.170

0.008*

0.012*

0.014*

0.017*

Figure II-3.  Data Summary Table for Metolachlor Residues on Oat Hay.

Table II-3.  Metolachlor Residue Data for Oat Hay.

EPA

Metolachlor

Oats, hay

Rotational crop

Residues

0.093

0.109

0.106

0.123

0.008*

0.012*

0.014*

0.017*

Figure II-4.  Data Summary Table for Metolachlor Residues on Oat Grain.

Table II-4.  Metolachlor Residue Data for Oat Grain.

EPA

Metolachlor

Oats, grain

Rotational Crop

Residues

0.026

0.030

0.020

0.021

0.007*

0.010*

0.012*

0.014*

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Figure II-5.  Data Summary Table for Metolachlor Residues on Oat straw.

Table II-5.  Metolachlor Residue Data for Oat Straw.

EPA

Metolachlor

Oats, straw

Rotational crop

Residues

0.164

0.123

0.124

0.091

0.008*

0.012*

0.014*

0.017*

Figure II-6.  Data Summary Table for Metolachlor Residues on Wheat
Forage.

Table II-6.  Metolachlor Residue Data for Wheat Forage.

EPA

Metolachlor

Wheat, forage

Rotational crop

Residues

0.163

0.102

0.354

0.262

0.008*

0.012*

0.014*

0.017*

Figure II-7.  Data Summary Table for Metolachlor Residues on Wheat hay.

Table II-7.  Metolachlor Residue Data for Wheat Hay.

EPA

Metolachlor

Wheat, hay

Rotational crop

Residues

0.352

0.453

0.331

0.213

0.008*

0.012*

0.014*

0.017*

Figure II-8.  Data Summary Table for Metolachlor Residues on Wheat
grain.

Table II-8.  Metolachlor Residue Data for Wheat Grain.

EPA

Metolachlor

Wheat, grain

Rotational crop

Residues

0.025

0.027

0.025

0.026

0.008*

0.012*

0.014*

0.017*

Figure II-9.  Data Summary Table for Metoachlor Residues on Wheat straw.

Table II-9.  Metolachlor Residue Data for Wheat Straw.

EPA

Metolachlor

Wheat, straw

Rotational crop

Residues

0.424

0.344

0.306

0.365

0.008*

0.012*

0.014*

0.017*

Metolachlor                                                             
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