UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

     OFFICE OF

PREVENTION, PESTICIDES

AND TOXIC SUBSTANCES

Date:		8-JUNE-2007

MEMORANDUM

SUBJECT:	Pyrasulfotole:  Human-Health Risk Assessment for Proposed Uses
on Small Cereal Grains.  PC Code:  000692.  PP#:  6F7059.  DP#:  328640.
 Decision #:  366490.

		Regulatory Action:  Section 3, Registration Action

		Risk Assessment Type:  Single Chemical Aggregate

FROM:	Jennifer R. Tyler, Chemist

Robert Mitkus, Ph.D., Toxicologist

		Kelly Lowe, Environmental Scientist

		Registration Action Branch 1 (RAB1)

		Health Effects Division (HED; 7509P)

THROUGH:	PV Shah, Ph.D., Acting Branch Chief

		RAB1/HED (7509P)

TO:		Tracy White/Dan Kenny, RM Team 23

		Registration Division (RD) (7505P)

The HED of the Office of Pesticide Programs (OPP) is charged with
estimating the risk to human health from exposure to pesticides.  The RD
of OPP has requested that HED evaluate hazard and exposure data and
conduct dietary, occupational, residential and aggregate exposure
assessments, as needed, to estimate the risk to human health that will
result from proposed tolerances for the new active ingredient (ai)
pyrasulfotole on small cereal grains.  A summary of the findings and an
assessment of human-health risk resulting from the proposed tolerances
for pyrasulfotole are provided in this document.  The risk assessment,
residue chemistry data review, and dietary exposure assessment were
provided by Jennifer Tyler (RAB1), the hazard characterization and
endpoint selection by Robert Mitkus (RAB1), and occupational exposure
assessment by Kelly Lowe (RAB1), and the drinking water exposure
assessment by Marietta Echeverria of the Environmental Fate and Effects
Division (EFED).

Table of Contents

  TOC \o "1-3" \h \z \u    HYPERLINK \l "_Toc170186426"  1.0	Executive
Summary	  PAGEREF _Toc170186426 \h  4

  HYPERLINK \l "_Toc170186427"  2.0	Ingredient Profile	  PAGEREF
_Toc170186427 \h  11

  HYPERLINK \l "_Toc170186428"  2.1	Summary of Proposed Uses	  PAGEREF
_Toc170186428 \h  12

  HYPERLINK \l "_Toc170186432"  2.2	Structure and Nomenclature	  PAGEREF
_Toc170186432 \h  13

  HYPERLINK \l "_Toc170186433"  2.3	Physical and Chemical Properties
PAGEREF _Toc170186433 \h  14

  HYPERLINK \l "_Toc170186434"  3.0	Hazard Characterization/Assessment
PAGEREF _Toc170186434 \h  14

  HYPERLINK \l "_Toc170186435"  3.1	Hazard and Dose-Response
Characterization	  PAGEREF _Toc170186435 \h  14

  HYPERLINK \l "_Toc170186436"  3.1.1	Database Summary	  PAGEREF
_Toc170186436 \h  14

  HYPERLINK \l "_Toc170186437"  3.2	Absorption, Distribution,
Metabolism, Excretion (ADME)	  PAGEREF _Toc170186437 \h  16

  HYPERLINK \l "_Toc170186438"  3.3	FQPA Considerations	  PAGEREF
_Toc170186438 \h  17

  HYPERLINK \l "_Toc170186439"  3.4	Hazard Identification and Toxicity
Endpoint Selection	  PAGEREF _Toc170186439 \h  18

  HYPERLINK \l "_Toc170186440"  3.4.1	Acute Reference Dose (aRfD)
PAGEREF _Toc170186440 \h  18

  HYPERLINK \l "_Toc170186441"  3.4.2	Chronic Reference Dose (cRfD)
PAGEREF _Toc170186441 \h  18

  HYPERLINK \l "_Toc170186442"  3.4.3	Incidental Oral Exposure (Short-
and Intermediate-Term)	  PAGEREF _Toc170186442 \h  18

  HYPERLINK \l "_Toc170186443"  3.4.4	Dermal Absorption	  PAGEREF
_Toc170186443 \h  18

  HYPERLINK \l "_Toc170186444"  3.4.5	Dermal Exposure (Short- and
Intermediate-Term)	  PAGEREF _Toc170186444 \h  19

  HYPERLINK \l "_Toc170186446"  3.4.6	Dermal Exposure (Long-Term)
PAGEREF _Toc170186446 \h  19

  HYPERLINK \l "_Toc170186447"  3.4.7	Inhalation Exposure (All
Durations)	  PAGEREF _Toc170186447 \h  19

  HYPERLINK \l "_Toc170186448"  3.4.9	Level of Concern for Margin of
Exposure	  PAGEREF _Toc170186448 \h  20

  HYPERLINK \l "_Toc170186449"  3.4.10	Recommendation for Aggregate
Exposure Risk Assessments	  PAGEREF _Toc170186449 \h  20

  HYPERLINK \l "_Toc170186450"  3.4.11	Classification of Carcinogenic
Potential	  PAGEREF _Toc170186450 \h  20

  HYPERLINK \l "_Toc170186451"  3.4.12	Summary of Toxicological Doses
and Endpoints for Pyrasulfotole for Use in Human-Health Risk Assessments
  PAGEREF _Toc170186451 \h  21

  HYPERLINK \l "_Toc170186452"  3.5	Endocrine Disruption	  PAGEREF
_Toc170186452 \h  23

  HYPERLINK \l "_Toc170186453"  4.0	Public Health and Pesticide
Epidemiology Data	  PAGEREF _Toc170186453 \h  23

  HYPERLINK \l "_Toc170186454"  5.0	Dietary Exposure/Risk
Characterization	  PAGEREF _Toc170186454 \h  24

  HYPERLINK \l "_Toc170186455"  5.1	Pesticide Metabolism and
Environmental Degradation	  PAGEREF _Toc170186455 \h  24

  HYPERLINK \l "_Toc170186456"  5.1.1	Metabolism in Primary Crops
PAGEREF _Toc170186456 \h  24

  HYPERLINK \l "_Toc170186457"  5.1.2	Metabolism in Rotational Crops
PAGEREF _Toc170186457 \h  25

  HYPERLINK \l "_Toc170186458"  5.1.3	Metabolism in Livestock	  PAGEREF
_Toc170186458 \h  26

  HYPERLINK \l "_Toc170186459"  5.1.4	Analytical Methodology	  PAGEREF
_Toc170186459 \h  26

  HYPERLINK \l "_Toc170186460"  5.1.5	Environmental Degradation
PAGEREF _Toc170186460 \h  27

  HYPERLINK \l "_Toc170186461"  5.1.6	Comparative Metabolic Profile
PAGEREF _Toc170186461 \h  28

  HYPERLINK \l "_Toc170186462"  5.1.7	Toxicity Profile of Major
Metabolites and Degradates	  PAGEREF _Toc170186462 \h  28

  HYPERLINK \l "_Toc170186463"  5.1.8	Pesticide Metabolites and
Degradates of Concern	  PAGEREF _Toc170186463 \h  29

  HYPERLINK \l "_Toc170186464"  5.1.9	Drinking Water Residue Profile
PAGEREF _Toc170186464 \h  31

  HYPERLINK \l "_Toc170186465"  5.1.10	Food Residue Profile	  PAGEREF
_Toc170186465 \h  32

  HYPERLINK \l "_Toc170186466"  5.1.11	International Residue Limits
PAGEREF _Toc170186466 \h  35

  HYPERLINK \l "_Toc170186467"  5.2	Dietary Exposure and Risk	  PAGEREF
_Toc170186467 \h  35

  HYPERLINK \l "_Toc170186468"  5.2.1	Acute Dietary Exposure/Risk
PAGEREF _Toc170186468 \h  36

  HYPERLINK \l "_Toc170186469"  5.2.2	Chronic Dietary Exposure/Risk
PAGEREF _Toc170186469 \h  36

  HYPERLINK \l "_Toc170186470"  6.0	Residential (Non-Occupational)
Exposure/Risk Characterization	  PAGEREF _Toc170186470 \h  37

  HYPERLINK \l "_Toc170186471"  6.1	Other (Spray Drift, etc.)	  PAGEREF
_Toc170186471 \h  37

  HYPERLINK \l "_Toc170186472"  7.0	Aggregate Risk Assessments and Risk
Characterization	  PAGEREF _Toc170186472 \h  37

  HYPERLINK \l "_Toc170186473"  7.1	Acute Aggregate Risk	  PAGEREF
_Toc170186473 \h  37

  HYPERLINK \l "_Toc170186474"  7.2	Chronic Aggregate Risk	  PAGEREF
_Toc170186474 \h  38

  HYPERLINK \l "_Toc170186475"  8.0	Cumulative Risk
Characterization/Assessment	  PAGEREF _Toc170186475 \h  38

  HYPERLINK \l "_Toc170186476"  9.0	Occupational Exposure/Risk Pathway
PAGEREF _Toc170186476 \h  39

  HYPERLINK \l "_Toc170186477"  9.1	Short-Term Handler Risk	  PAGEREF
_Toc170186477 \h  39

  HYPERLINK \l "_Toc170186478"  9.2	Short-Term Post-application Risk
PAGEREF _Toc170186478 \h  40

  HYPERLINK \l "_Toc170186479"  10.0	Data Needs and Label
Recommendations	  PAGEREF _Toc170186479 \h  42

  HYPERLINK \l "_Toc170186480"  10.1	Toxicology	  PAGEREF _Toc170186480
\h  42

  HYPERLINK \l "_Toc170186481"  10.2	Residue Chemistry	  PAGEREF
_Toc170186481 \h  42

  HYPERLINK \l "_Toc170186482"  Appendix A.	Toxicology Assessment
PAGEREF _Toc170186482 \h  43

  HYPERLINK \l "_Toc170186483"  A.2.	Toxicity Profiles	  PAGEREF
_Toc170186483 \h  44

  HYPERLINK \l "_Toc170186484"  A.3.	Executive Summaries	  PAGEREF
_Toc170186484 \h  51

  HYPERLINK \l "_Toc170186485"  Appendix B.	Metabolism Assessment
PAGEREF _Toc170186485 \h  72

1.0	Executive Summary  TC "1.0	Executive Summary" \f C \l "1"

Bayer CropSciences has submitted a petition for the use of
pyrasulfotole, a new postemergence dicot herbicide, for use on small
cereal grains, including wheat, barley, oats, rye and triticale.
Pyrasulfotole is an effective inhibitor of the enzyme
4-hydroxyphenylpyruvate dioxygenase (HPPD) and consequently blocks the
pathway of prenylquinone biosynthesis in plants.  The end-use products
are applied to the target weeds and act primarily through leaf uptake
and translocation to the target site.  The first symptoms appear three
to five days after application.  Bleaching and discoloration appear
initially and symptoms progress to tissue necrosis and plant death
within two weeks.

There are currently no food/feed uses or tolerances for pyrasulfotole in
the United States (U.S.).  In addition, there are currently no
registered or proposed residential uses for pyrasulfotole.
Pyrasulfotole is being evaluated as part of a trilateral joint review
with Canada and Australia.

Pyrasulfotole will be formulated as AE 0317309 SE06 Herbicide, a
suspo-emulsion (SE) containing 50 grams (g)/liter (L) of pyrasulfotole
and the safener mefenpyr-diethyl; and AE 0317309 + Bromo Herbicide, an
emulsifiable concentrate (EC) comprised of 37.5 g/L of pyrasulfotole,
bromoxynil (present as the mixed heptanoate and octanoate esters), and
the safener mefenpyr-diethyl on cereal grains.  The SE and EC
formulations are being proposed for one ground or foliar application per
season to the above crops at rates of 0.045 lb pyrasulfotole/A and 0.037
lb pyrasulfotole/A, respectively.  HED notes that this document pertains
to the ai pyrasulfotole only.

Hazard Assessment:  The toxicology database for pyrasulfotole is
considered complete and adequate for purposes of risk assessment.
Pyrasulfotole has a low to moderate order of acute toxicity (Appendix
A.2) via the oral, dermal, and inhalation routes (Category III or IV).
Pyrasulfotole is not a dermal sensitizer or irritant (Category IV) and
has been shown to be a moderate eye irritant (Category III).  The eye is
the primary target organ of pyrasulfotole.  Decreased locomotor activity
was observed on the day of treatment in the acute neurotoxicity study in
the rat.

Ocular toxicity was observed in male and female rats exposed to
pyrasulfotole for 90 days (subchronic oral exposure) either in the diet
or by gavage.  Mortality and multi-organ histopathology in the kidney,
urinary bladder, thyroid, and ureters were also observed in the dietary
study.  In mice, toxicity of the urinary bladder was observed in males,
while toxicity of the adrenal glands was observed in females treated in
the diet for 28 days.  Neither effect was reproduced in the 90-day
toxicity study in mice; however, urinary bladder toxicity was observed
in the 29-day toxicity study in the dog, the 90-day toxicity study in
the rat, and the mouse carcinogenicity study.  Rats treated with
pyrasulfotole for 28 days by the dermal route demonstrated toxicity of
the thyroid and pancreas.

Chronic oral exposure of rats to pyrasulfotole resulted in extensive eye
toxicity at almost all doses tested.  These included corneal opacity,
neovascularization of the cornea, inflammation of the cornea,
regenerative corneal hyperplasia, corneal atrophy, and/or retinal
atrophy.  Ocular toxicity is believed to be an indirect result of
tyrosinemia caused by inhibition of hepatic HPPD. In mice, ocular
toxicity was not observed at any dose, thereby reflecting accepted
differences in effects among rodent species for HPPD inhibitors.
Long-term exposure of mice to pyrasulfotole did cause toxicity of the
urinary system, including the kidney, urinary bladder, and ureters at
the highest dose tested, as well as gallstone formation at all doses
tested.  Dogs treated with pyrasulfotole for one year exhibited toxicity
of the urinary system (kidneys and bladder) at mid and high doses, as
well as cataracts at a very low incidence at the highest dose tested.

In the combined chronic/carcinogenicity study in rats, an increase in
the incidence of corneal squamous cell tumors was observed in males only
at the highest dose tested.  HED’s Carcinogenicity Assessment Review
Committee (CARC) considered these rare tumors, which were observed
following adequate dosing, to be treatment-related.  In the
carcinogenicity study in mice, an increase in the incidence of
transitional cell carcinomas and papillomas of the urinary bladder were
observed in males and females at the highest dose tested.  However,
these tumors were observed at doses that were considered excessive due
to increased mortality caused by urinary bladder stones.  Pyrasulfotole
was negative for mutations and chromosomal aberrations across four in
vitro/in vivo genotoxicity studies and was considered by the CARC not to
pose a mutagenic concern.

In the prenatal developmental toxicity study in rats, an increased
incidence of skeletal variations was observed in fetal offspring at the
mid dose, as was decreased fetal body weight in male offspring.  Both
effects were observed in the presence of maternal toxicity (decreased
body weight gain, enlarged placenta, clinical signs) at the same dose.
In the developmental neurotoxicity (DNT) study in rats, ocular toxicity
as well as several adverse developmental effects (delayed preputial
separation, morphometric changes, delays in learning/memory) were
observed at the mid dose.  Ocular toxicity was also observed at this
dose in maternal animals; an identical no-observed-adverse-effect-level
(NOAEL) was established in both dams and offspring.  In the prenatal
developmental toxicity study in rabbits, an increased incidence of
skeletal variations was observed in fetal offspring at the mid dose.
However, maternal toxicity (decreased body weight gain and food
consumption) was observed only at the next highest dose tested.
Therefore, increased quantitative susceptibility of offspring was
observed in the rabbit developmental toxicity study, but not in the
developmental toxicity study in rats or DNT study in rats.

In the 2-generation reproductive toxicity study in rats, ocular toxicity
(keratitis, corneal opacity and/or corneal neovascularization), was
observed at the mid and high doses in the adults and offspring of two
generations.  Thyroid (colloid alteration, pigment deposition) and
kidney (tubular dilation) toxicity were observed in adult animals of
each generation.  Colloid alteration and pigment deposition were also
observed in rats following short-term dermal and chronic oral exposure
of rats, although they were attributed to aging in the latter case.  At
the highest dose tested, decreased viability and decreased body weight
were observed in offspring of both generations.  At the mid and/or high
doses, delays in balanopreputial separation (males) and vaginal patency
(females) were observed in first-generation offspring.

Following oral administration of 10 mg/kg phenyl or pyrazole
ring-labeled pyrasulfotole, ~60% of radiolabeled compound was excreted
in the urine after 6 hours, while ~73% of the administered dose was
recovered in the urine by the time of sacrifice (52 hours).  Therefore,
approximately 60% of the compound was absorbed within 6 hours of
exposure.  Less than 2% of the administered dose remained in the
residual carcass and tissues at sacrifice, and the highest residues were
found in the liver and kidney.  Approximately 30% of labeled compound
was excreted in the feces 52 hours after dosing, approximately 25% of
which was parent.  Pyrasulfotole was metabolized via hydroxylation and
N-demethylation.

Dose Response Assessment and Food Quality Protection Act (FQPA)
Decision:  The pyrasulfotole risk assessment team recommends that the
10X FQPA safety factor (SF) for the protection of infants and children
be reduced to 1X since there is a complete toxicity database for
pyrasulfotole and exposure data are complete or are estimated based on
data that reasonably account for potential exposures.  The
recommendation is based on the following:  1) Clear NOAELs were
established for all exposure scenarios and these are considered
protective of the offspring susceptibility observed in the rabbit
developmental toxicity study.  2) There are no residual uncertainties
concerning pre- and postnatal toxicity.  3) There are no residual
uncertainties with respect to exposure data.  4) The dietary food
exposure assessment utilizes tolerance-level residues and 100% crop
treated (CT) information for all proposed commodities.  By using this
screening-level assessment, the acute and chronic exposures/risks will
not be underestimated.  5) The dietary drinking water assessment (Tier 1
estimates) utilizes values generated by model and associated modeling
parameters which are designed to provide conservative, health
protective, high-end estimates of water concentrations.  6) There are no
registered or proposed uses of pyrasulfotole which would result in
residential exposure.

Risk assessments were conducted for the following specific exposure
scenarios listed below.  The acute and chronic reference doses (aRfD and
cRfD) were calculated by dividing the NOAEL by 100 (10X for interspecies
extrapolation and 10X for intraspecies variation).  Since the FQPA SF
has been reduced to 1X, the acute and chronic population adjusted doses
(aPAD and cPAD) are equal to the aRfD and cRfD, respectively.  The
dermal absorption factor was estimated to be 2.5%; however, a dermal
penetration study is required to confirm the estimate.  A 100 % oral
equivalent inhalation absorption factor is assumed.  The level of
concern (LOC) for occupational dermal and inhalation exposures are for
margins of exposure (MOEs) <100.

Exposure Scenario	Point of Departure	RfD, PAD, LOC for Risk Assessment
Study/Effect

Acute dietary	NOAEL = 3.8 mg/kg/day	aRfD and aPAD  = 0.038 mg/kg/day
Developmental neurotoxicity study in rats/Delayed preputial separation
(males), decreased cerebrum length (PND 21 females), and decreased
cerebellum height (PND 21 males)

Chronic dietary	NOAEL = 1.0 mg/kg/day	cRfD and cPAD = 0.01 mg/kg/day
Combined chronic toxicity/carcinogenicity study in rats/Corneal opacity,
neovascularization of the cornea, inflammation of the cornea,
regenerative corneal hyperplasia, corneal atrophy, and/or retinal
atrophy (both sexes), and hepatocellular hypertrophy along with
increased serum cholesterol (males)

Short-term dermal	NOAEL = 10 mg/kg/day	LOC for MOE < 100 (occupational)
28-day dermal toxicity in rats/Focal degeneration of pancreas (both
sexes) and alteration of thyroid colloid (males)

Short-term inhalation	NOAEL = 1.0 mg/kg/day	LOC for MOE < 100
(occupational)	Combined chronic toxicity/carcinogenicity study in
rats/Corneal opacity, neovascularization of the cornea, inflammation of
the cornea, regenerative corneal hyperplasia, corneal atrophy, and/or
retinal atrophy (both sexes), and hepatocellular hypertrophy along with
increased serum cholesterol (males)

Residue Chemistry and Drinking Water Assessments:  The residue chemistry
and drinking water databases are adequate to assess potential human
exposure to pyrasulfotole.  Several residue chemistry deficiencies have
been determined as listed in Section 10.0 of this risk assessment.

For the purposes of this risk assessment only, the residues of concern
in cereal grains (primary crops) and livestock for tolerance and risk
assessment purposes are pyrasulfotole and its metabolite
pyrasulfotole-desmethyl.  For rotational crops, the residue of concern
is parent per se for tolerance and risk assessment purposes.  For
drinking water, the residue of concern for risk assessment purposes is
pyrasulfotole per se.

Adequate crop field trial data have been submitted for wheat, barley and
oats.  For all commodities, the data reflect the maximum rates and
minimum PHIs requested and have sufficient geographic representation to
support tolerances for the proposed uses (See Appendix C).  All crop
field trial studies are supported by adequate storage stability data.
Adequate processing data have been submitted for wheat, and indicate
that tolerances should be established for oat, bran.  Based on the
available livestock feeding and poultry metabolism studies, and in order
to harmonize with Canada’s Pesticide Management Regulatory Agency
(PMRA) policy, tolerances on livestock commodities should be established
(see Appendix C).  Provided that two ion transitions are monitored
during mass spectrometry (MS)/MS analysis for each analyte, there is an
adequate analytical method to enforce the recommended tolerances for
cereal grains.  For livestock commodities, the company should submit an
analytical method to measure both residues of pyrasulfotole and
pyrasulfotole-desmethyl.  It should be noted that the Analytical
Chemistry Branch of the Biological & Economics Analysis Division
(ACB/BEAD) believes that the proposed analytical enforcement method will
work for pyrasulfotole-desmethyl (e-mail from C. Stafford to J. Tyler;
3/3/007).  Therefore, HED is recommending for a conditional registration
until an updated method is submitted.

The existing confined and field rotational crop data are adequate to
support the proposed rotational crop restrictions.

The available environmental fate data indicate that pyrasulfotole is
likely to be persistent and mobile to moderately mobile in the
environment.  EFED provided Tier 1 estimated drinking water
concentrations (EDWCs) for surface and ground water which were generated
using the FQPA Index Reservoir Screening Tool (FIRST) and Screening
Concentration in Ground Water (SCIGROW) models, respectively.

Dietary (Food and Drinking Water) Exposure Estimates:  Acute and chronic
dietary exposure analyses were conducted using the Dietary Exposure
Evaluation Model-Food Commodity Intake Database (DEEM-FCID(; ver. 2.03)
program which incorporates consumption data from the United States
Department of Agriculture’s (USDA’s) Continuing Surveys of Food
Intakes by Individuals (CSFII), 1994-1996/1998.  For acute and chronic
dietary risk estimates, HED’s level of concern is for estimates that
exceed 100% aPAD or cPAD, respectively.

Unrefined, acute and chronic dietary exposure assessments were performed
for the general U.S. population and various other population subgroups
(including infants and children) using tolerance-level residues and
assuming 100% CT for all proposed uses.  Drinking water was incorporated
directly in the dietary assessment using the acute or chronic
concentrations for surface water generated by the FIRST model.  The
acute dietary exposure estimates (95th percentile) are not of concern to
HED (<100% of the aPAD) for the general U.S. population (2% of the aPAD)
and all other population subgroups.  The most highly-exposed population
subgroup is children 1-2 years old at 4% of the aPAD.  The chronic
dietary exposure estimates are not of concern to HED (<100% of the cPAD)
for the general U.S. population (2% of the cPAD) and all population
subgroups.  The most highly exposed population subgroup is children 1-2
years old at 7% of the cPAD.

Aggregate Exposure Scenarios and Risk Conclusions:  For the proposed
uses, human health aggregate risk assessments have been conducted for
the following exposure scenarios:  acute aggregate exposure (food +
drinking water), and chronic aggregate exposure (food + drinking water).
 Short- and intermediate-term aggregate risk assessments were not
performed because there are no registered or proposed residential uses
for pyrasulfotole.  A cancer aggregate risk assessment was not performed
because pyrasulfotole is classified as “Suggestive Evidence of
Carcinogenic Potential” by the HED CARC.  All potential exposure
pathways were assessed in the aggregate risk assessment.  All aggregate
exposure and risk estimates are not of concern to HED for the scenarios
listed above.

Occupational Exposure Estimates:  Based on the proposed use patterns (1
application per season), short-term (1-30 days) dermal and inhalation
exposures are expected for commercial and private applicators.  The most
highly exposed occupational workers are expected to be mixer/loaders
using open-pour loading of liquids for aerial applications, and
applicators using aerial equipment.  No chemical-specific data are
available with which to assess potential exposure to pesticide handlers;
therefore, estimates of exposure are based on data available in the
Pesticide Handler Exposure Database Version 1.1 (PHED Surrogate Exposure
Guide, 8/98).  Exposure/risks for short-term dermal and inhalation
handler mixer/loader exposures were presented at baseline (workers
wearing a single layer of work clothing consisting of a long-sleeved
shirt, long pants, shoes plus socks and no protective gloves).  .  HED
has no data to assess exposures to pilots using open cockpits.  The
only data available is for exposure to pilots in enclosed cockpits.
Therefore, risks to pilots are assessed using the engineering control
(enclosed cockpits) and baseline attire (long-sleeve shirt, long pants,
shoes, and socks). All occupational handler MOEs are >100 with baseline
attire; and, therefore, are not of concern to HED (i.e., MOE >100).

Short-term (1-30 days) dermal exposures are expected for
post-application agricultural activities.  Post-application inhalation
exposure is expected to be negligible due to the low vapor pressure of
pyrasulfotole.  The labels for pyrasulfotole recommend that the products
be applied between the 1 leaf and up to flag leaf emergence.  There are
no chemical-specific data with which to estimate post-application
exposure of agricultural workers to dislodgeable residues of
pyrasulfotole.  Therefore, post-application worker exposure was
estimated using the HED Science Advisory Council for Exposure Policy
(ExpoSAC; Policy 003.1, Rev. 7 Aug. 2000, Regarding Agricultural
Transfer Coefficients (TCs); Amended ExpoSAC Meeting notes - 13 Sept
01), which lists scouting and irrigating as the activities with the
highest (i.e., most conservative) TCs related to the proposed uses.  All
MOEs are >100; therefore, post-application dermal exposure to
agricultural workers is not of concern to HED (i.e., MOE >100).

Based on the acute Toxicity Category classification for pyrasulfotole,
the interim worker protection standard (WPS) restricted-entry interval
(REI) of 12 hours is adequate to protect agricultural workers from
post-application exposures.  The two proposed end-use product labels
list an REI of 12 hours.

Environmental Justice Considerations:  Potential areas of environmental
justice concerns, to the extent possible, were considered in this
human-health risk assessment, in accordance with U.S. Executive Order
12898, "Federal Actions to Address Environmental Justice in Minority
Populations and Low-Income Populations," (  HYPERLINK
"http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf"
http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf ).

As a part of every pesticide risk assessment, OPP considers a large
variety of consumer subgroups according to well-established procedures.
In line with OPP policy, HED estimates risks to population subgroups
from pesticide exposures that are based on patterns of that subgroup’s
food and water consumption, and activities in and around the home that
involve pesticide use in a residential setting.  Extensive data on food
consumption patterns are compiled by the USDA under CSFII and are used
in pesticide risk assessments for all registered food uses of a
pesticide.  These data are analyzed and categorized by subgroups based
on age, season of the year, ethnic group, and region of the country.
Additionally, OPP is able to assess dietary exposure to smaller,
specialized subgroups and exposure assessments are performed when
conditions or circumstances warrant.  Whenever appropriate, non-dietary
exposures based on home use of pesticide products and associated risks
for adult applicators and for toddlers, youths, and adults entering or
playing on treated areas post-application are evaluated.  Further
considerations are currently in development as OPP has committed
resources and expertise to the development of specialized software and
models that consider exposure to bystanders and farm workers as well as
lifestyle and traditional dietary patterns among specific subgroups.

Review of Human Research:  This risk assessment relies in part on data
from PHED studies in which adult human subjects were intentionally
exposed to a pesticide or other chemical.  These studies have been
determined to require a review of their ethical conduct, and have
received that review.

Recommendations for Tolerances:  Provided revised Sections B and F are
submitted and analytical reference standards for pyrasulfotole,
pyrasulfotole-desmethyl and labeled internal standards are submitted to
the EPA National Pesticide Standards Repository, the residue chemistry,
toxicological, and occupational databases support the establishment of a
conditional registration and the following permanent tolerances for
residues of pyrasulfotole and its metabolite pyrasulfotole-desmethyl
(see Appendix C for a detailed listing of the HED-recommended
tolerances):

Wheat, grain	0.02 ppm	Cattle, meat byproducts, except liver	0.06 ppm

Wheat, straw	0.20 ppm	Cattle, liver	0.35 ppm

Wheat, forage	0.20 ppm	Goat, fat	0.02 ppm

Wheat, hay	0.80 ppm	Goat, meat byproducts, except liver	0.06 ppm

Aspirated grain fractions	0.40 ppm	Goat, liver	0.35 ppm

Oat, grain	0.08 ppm	Sheep, meat	0.02 ppm

Oat, straw	0.20 ppm	Sheep, fat	0.02 ppm

Oat, forage	0.10 ppm	Sheep, meat byproducts, except liver	0.06 ppm

Oat, hay	0.50 ppm	Sheep, liver	0.35 ppm

Barley, grain	0.02 ppm	Horse, meat byproducts, except liver	0.05 ppm

Barley, straw	0.20 ppm	Horse, liver	0.30 ppm

Barley, hay	0.30 ppm	Hog, meat	0.02 ppm

Rye, grain	0.02 ppm	Hog, fat	0.02 ppm

Rye, straw	0.20 ppm	Hog, meat byproducts	0.02 ppm

Rye, forage	0.20 ppm	Poultry, meat	0.02 ppm

Milk	0.01 ppm	Poultry, fat	0.02 ppm

Cattle, meat	0.02 ppm	Poultry, meat byproducts	0.02 ppm

Cattle, fat	0.02 ppm	Eggs	0.02 ppm

Goat, meat	0.02 ppm

The registration should be made unconditional upon submission of the
following:

Submission of a new ruminant analytical enforcement method to determine
residues of pyrasulfotole and pyrasulfotole-desmethyl as well as
adequate radiovalidation and independent laboratory validation (ILV)
data.  Upon submission, the method will be forwarded to ACB/BEAD for a
petition method validation (PMV) trial.  Successful completion of the
PMV trial will be necessary before Method AI-004-A05-01 can be
considered adequate for tolerance-enforcement purposes.

For Method AI-001-P04-01, the ACB recommends that the petitioner provide
information for a second MS/MS ion transition to provide a confirmation
of analyte identities.  If two ion transitions are not available, HED
recommends that the petitioner provide an alternate chromatographic
column and/or mobile-phase combination to add an additional degree of
specificity and further reduce the possibility of false positive
residues.

In vivo dermal penetration study.

2.0	Ingredient Profile  TC "2.0	Ingredient Profile" \f C \l "1"

Pyrasulfotole is a postemergence dicot herbicide for use on small cereal
grains, including wheat, barley, oats, rye and triticale.  Pyrasulfotole
is an effective inhibitor of the enzyme HPPD and consequently blocks the
pathway of prenylquinone biosynthesis in plants.  The end-use products
are applied to the target weeds and act primarily through leaf uptake
and translocation to the target site.  The first symptoms appear three
to five days after application.  Bleaching and discoloration appear
initially and symptoms progress to tissue necrosis and plant death
within two weeks.

As pyrasulfotole is a new ai, there are no tolerances currently
established for pyrasulfotole under 40 CFR.  Pyrasulfotole is being
evaluated as part of a trilateral joint review with Canada and
Australia.

Pyrasulfotole will be formulated as AE 0317309 SE06 Herbicide, a SE
formulation containing 50 g/L of pyrasulfotole and the safener
mefenpyr-diethyl; and AE 0317309 EC23 Herbicide, an EC formulation
comprised of 37.5 g/L of pyrasulfotole, bromoxynil (present as the mixed
heptanoate and octanoate esters), and the safener mefenpyr-diethyl on
cereal grains.  The following rotational crop restrictions are listed on
both the SE and EC labels:  7 days for wheat (spring, durum, winter) and
spring barley; 4 months for soybeans; 9 months for alfalfa, canaryseed,
canola, corn, flax, field peas, lentils, and tame oats; and 12 months
for mustards.  Rotational crop restriction for all other crops not
listed on label were not included.  Table 2.1 is a summary of the
proposed use patterns.

2.1	Summary of Proposed Uses  TC "2.1	Summary of Proposed Uses" \f C \l
"2"

Table 2.1.  Summary of Proposed Use Patterns.

Crops	Product

(EPA Reg. No.)	Application Timing; Type; and Equip.	# App.	Application
Rate

(lb ai/A)	RTI1 (days)	PHI1

(days)	Restrictions

Per app.	Per season

	Wheat, barley, oats and triticale.	AE 0317309 02 SE06 (No EPA Reg. No.)
Crop application – apply between 1 leaf and up to flag leaf emergence.

Ground and aerial equipment.	1	0.045	0.045	NA	Barley and oats grain or
straw- 45;

Wheat and triticale grain or straw – 50; grazing or foraging – 25
days.	Apply ground app. in 10-15 gal/A, and aerial app. in minimum of 5
gal/A.

Wheat, barley, oats, rye and triticale.	Huskie Herbicide (No EPA Reg.
No.)	Crop application – apply between 1 leaf and up to flag leaf
emergence.

Fallow application – apply in fallow period prior to planting or the
emergence of crops listed on label.

Ground, sprinkler irrigation (wheat and barley only), and aerial
equipment.	1	0.0037	0.0037	NA	Grain and straw – 60 days; grazing or
foraging – 25 days.

	Ground app.- Apply in minimum of 5 gal/A; Aerial app. – Apply in
minimum of 5 gal/A.

Instructions on additives, such as non-ionic surfactants are included on
label.

1 RTI = retreatment interval; PHI = preharvest interval;  NA = not
applicable.

HED Conclusions:  The use directions provided by the petitioner are
adequate to allow evaluation of the residue data relative to the
proposed uses on small cereal grains, with the exception of the
rotational crop restrictions.  Section B of the petition should be
revised to include instructions on rotation to all other crops not
currently listed.

2.2	Structure and Nomenclature  TC "2.2	Structure and Nomenclature" \f
C \l "2"

The test compound and metabolite nomenclature are presented below in
Table 2.2.

Empirical Formula	C14H13F3N2O4S

Common name	Pyrasulfotole

Company Experimental name	AE 0317309

IUPAC name	5-hydroxy-1,3-dimethylpyrazol-4-yl
2-mesyl-4-(trifluoromethyl)phenyl ketone

CAS name
(5-hydroxy-1,3-dimethyl-1H-pyrazol-4-yl)[2-(methylsulfonyl)-4-(trifluoro
methyl)phenyl]methanone

CAS #	365400-11-9

End-use product/(EP)	AE 0317309 SE06 Herbicide and AE 0317309 EC23
Herbicide

Compound	Chemical Structure

Common name	Pyrasulfotole-desmethyl

Company Experimental name	AE 1073910

CAS name
(5-hydroxy-1H-pyrazol-4-yl)[2-mesyl-4-(trifluoromethyl)phenyl]methanone

Compound	Chemical Structure

Common name	Pyrasulfotole-benzoic acid

Company Experimental name	AE B197555

CAS name	2-(Methylsulfonyl)-4-(trifluoromethyl)benzoic acid

2.3	Physical and Chemical Properties  TC "2.3	Physical and Chemical
Properties" \f C \l "2"

The physicochemical properties of pyrasulfotole are presented below in
Table 2.3.

Table 2.3.  Physicochemical Properties of the Technical Grade Test
Compound.

Parameter	Value	Reference

Melting point	Pure: 201°C

No boiling point, decomposition starts at 245°C	MRID 46801701

pH at 22.9°C	3.03

	Density	1.53

	Water solubility (g/L at 20(C)	2.3

4.2

69.1

49.0

	pH 3.0 (distilled water)

pH 3.9 (buffer pH 4.0)

pH 5.4 (buffer pH 7.0)*

pH 5.2 (buffer pH 9.0)*

* exceeded buffer capacity

	Solvent solubility (g/L at 20(C)	Ethanol

n-Hexane

Tolune

Dichloromethane

Acetone

Ethyl acetate

Dimethyl sulfoxide	21.6

0.038

6.86

120-150

89.2

37.2

≥ 600

	Vapor pressure at 20(C	2.7 X 10-7 Pa

	Dissociation constant (pKa)	4.2

	n-octanol-water partition coefficient Log(KOW) at 23°C	0.276

-1.362

-1.580 	pH 4.0

pH 7.0

pH 9.0

	UV/visible absorption spectrum	max= 264, 241, 216 nm in water, 0.1M
HCl, 0.1M NaOH respectively.

3.0	Hazard Characterization/Assessment  TC "3.0	Hazard
Characterization/Assessment" \f C \l "1"

3.1	Hazard and Dose-Response Characterization  TC "3.1	Hazard and
Dose-Response Characterization" \f C \l "2"

3.1.1	Database Summary  TC "3.1.1	Database Summary" \f C \l "3"

<IP_ADDRESS>	Studies Available and Considered  TC "<IP_ADDRESS>	Studies Available
and Considered" \f C \l "4"

Data from the following studies were used to evaluate the hazard
potential of pyrasulfotole:

Acute: One acute neurotoxicity study (rat) and standard acute toxicity
battery

Subchronic: Two oral (rat), two oral (dog), and two oral (mouse)
toxicity studies; and one dermal toxicity study (rat)

Developmental: Two prenatal developmental toxicity studies (rat, rabbit)
and one developmental neurotoxicity study (rat)

Reproduction: One 2-generation reproductive toxicity study (rat)

Chronic: One combined oral toxicity/carcinogenicity study in rat, one
carcinogenicity study in mouse, and one oral (1-year) toxicity study in
dog

Genotoxicity: Four in vivo/in vitro genotoxicity screens (including
mutagenicity)

Metabolism: one metabolism study (rat; Tier 1)

Special: Four mechanistic studies

<IP_ADDRESS>	 Mammalian Mechanism of Action for Ocular Toxicity  TC "<IP_ADDRESS>
Mammalian Mechanism of Action" \f C \l "4"

Pyrasulfotole is an inhibitor of the hepatic enzyme HPPD.  HPPD is an
important enzyme in the catabolism of the amino acid tyrosine.  In
mammals, inhibition of HPPD leads to an increase in blood tyrosine
concentrations (tyrosinemia) that is often followed by ocular toxicity.

<IP_ADDRESS>	Sufficiency of Studies/Data  TC "<IP_ADDRESS>	Sufficiency of
Studies/Data" \f C \l "4"

The toxicity database is complete for pyrasulfotole and is adequate for
risk assessment evaluations and determination of FQPA.  All studies
evaluated were deemed acceptable and met guideline criteria.

3.1.2 	Mammalian Toxicology  TC "3.1.2 	Mammalian Toxicology" \f C \l
"3"

Pyrasulfotole has a low to moderate order of acute toxicity (Appendix
A.2) via the oral, dermal, and inhalation routes (Category III or IV).
Pyrasulfotole is not a dermal sensitizer or irritant (Category IV) and
has been shown to be a moderate eye irritant (Category III).  Decreased
locomotor activity was observed on the day of treatment in the acute
neurotoxicity study in the rat.

Ocular toxicity was observed in male and female rats exposed to
pyrasulfotole for 90 days (subchronic) either in the diet or by gavage.
Mortality and multi-organ histopathology in the kidney, urinary bladder,
thyroid, and ureters were also observed in the dietary study.  In mice,
toxicity of the urinary bladder was observed in males, while toxicity of
the adrenal glands was observed in females treated in the diet for 28
days.  Neither effect was reproduced in the 90-day toxicity study in
mice; however, urinary bladder toxicity was observed in the 29-day
toxicity study in the dog, the 90-day toxicity study in the rat, and the
mouse carcinogenicity study.  Rats treated with pyrasulfotole for 28
days by the dermal route demonstrated toxicity of the thyroid and
pancreas.

Chronic oral exposure of rats to pyrasulfotole resulted in extensive eye
toxicity at almost all doses tested.  These included corneal opacity,
neovascularization of the cornea, inflammation of the cornea,
regenerative corneal hyperplasia, corneal atrophy, and/or retinal
atrophy.  Ocular toxicity is believed to be an indirect result of
tyrosinemia caused by inhibition of hepatic HPPD, as mentioned above.
In mice, ocular toxicity was not observed at any dose, thereby
reflecting accepted differences in effects among rodent species for HPPD
inhibitors.  Long-term exposure of mice to pyrasulfotole did cause
toxicity of the urinary system, including the kidney, urinary bladder,
and ureters at the highest dose tested, as well as gallstone formation
at all doses tested.  Dogs treated with pyrasulfotole for one year
exhibited toxicity of the urinary system (kidneys and bladder) at mid
and high doses, as well as cataracts at a very low incidence at the
highest dose tested.

In the combined chronic/carcinogenicity study in rats, an increase in
the incidence of corneal squamous cell tumors was observed in males only
at the highest dose tested.  HED’s CARC considered these rare tumors,
which were observed following adequate dosing, to be treatment-related.
In the carcinogenicity study in mice, an increase in the incidence of
transitional cell carcinomas and papillomas of the urinary bladder were
observed in males and females at the highest dose tested.  However,
these tumors were observed at doses that were considered excessive due
to increased mortality caused by urinary bladder stones.  Pyrasulfotole
was negative for mutations and chromosomal aberrations across four in
vitro/in vivo genotoxicity studies and was considered by the CARC not to
pose a mutagenic concern.

In the prenatal developmental toxicity study in rats, an increased
incidence of skeletal variations was observed in fetal offspring at the
mid dose, as was decreased fetal body weight in male offspring.  Both
effects were observed in the presence of maternal toxicity (decreased
body weight gain, enlarged placenta, clinical signs) at the same dose.
In the DNT study in rats, ocular toxicity as well as several adverse
developmental effects (delayed preputial separation, morphometric
changes, delays in learning/memory) were observed at the mid dose.
Ocular toxicity was also observed at this dose in maternal animals; an
identical NOAEL was established in both dams and offspring.  In the
prenatal developmental toxicity study in rabbits, an increased incidence
of skeletal variations was observed in fetal offspring at the mid dose.
However, maternal toxicity (decreased body weight gain and food
consumption) was observed only at the next highest dose tested.
Therefore, increased susceptibility of offspring was observed in the
rabbit developmental toxicity study but not in the developmental
toxicity study in rats or DNT study in rats.

In the 2-generation reproductive toxicity study in rats, ocular toxicity
(keratitis, corneal opacity and/or corneal neovascularization), was
observed at the mid and high doses in the adults and offspring of two
generations.  Thyroid (colloid alteration, pigment deposition) and
kidney (tubular dilation) toxicity were observed in adult animals of
each generation.  Colloid alteration and pigment deposition were also
observed in adult rats following short-term dermal and chronic oral
exposure of rats, although they were attributed to aging in the latter
case.  Colloid alteration and pigment deposition were of minimal
severity in the 2-generation reproductive toxicity study and therefore
not of concern.  At the highest dose tested, decreased viability and
decreased body weight were observed in offspring of both generations.
At the mid and/or high doses, delays in balanopreputial separation
(males) and vaginal patency (females) were observed in first-generation
offspring.

3.2	Absorption, Distribution, Metabolism, Excretion (ADME)  TC "3.2
Absorption, Distribution, Metabolism, Excretion (ADME)" \f C \l "2"

One single/low-dose disposition study by the oral and intravenous routes
in rats was performed with pyrasulfotole.  Following oral administration
of 10 mg/kg phenyl or pyrazole ring-labeled pyrasulfotole, ~60% of
radiolabeled compound was excreted in the urine after 6 hours, while
~73% of the administered dose was recovered in the urine by the time of
sacrifice (52 hours).  Therefore, approximately 60% of the compound was
absorbed within 6 hours of exposure.  Less than 2% of the administered
dose remained in the residual carcass and tissues at sacrifice, and the
highest residues were found in the liver and kidney.
Hydroxymethyl-parent, desmethyl-parent, and benzoic acid metabolite were
observed as metabolites in urine and feces at levels of 2%, <9%, and <2%
of the administered dose.  Further biotransformation (including Phase II
metabolism) is unknown.  Approximately 30% of labeled compound was
excreted in the feces 52 hours after dosing, approximately 25% of which
was parent.  Following intravenous injection, approximately 5% of parent
compound was excreted in feces.  This implies that 5% of systemically
absorbed parent compound is excreted in the bile.  No metabolism or
absorption studies are available via the dermal or inhalation routes.

3.3	FQPA Considerations  TC "3.3	FQPA Considerations" \f C \l "2"

Executive summaries of developmental toxicity, developmental
neurotoxicity, and reproductive toxicity studies are located in Appendix
A.2.  Increased quantitative susceptibility of offspring was observed in
the rabbit developmental toxicity study, since offspring toxicity
(skeletal anomalies/variations) was observed at a lower dose than
maternal toxicity (decreased body weight gain, food consumption).  No
evidence of quantitative susceptibility following in utero and/or
postnatal exposure was observed in the prenatal developmental toxicity
study in rats, the developmental neurotoxicity (DNT) study in rats, or
in the 2-generation rat reproductive toxicity study.  Offspring toxicity
[skeletal variations; decreased body weight (males)] was observed at the
same dose as maternal toxicity (clinical signs, decreased body weight,
enlarged placenta) in the prenatal developmental toxicity study in rats.
 Offspring toxicity (e.g., ocular toxicity, effects on learning/memory,
effects on brain morphometry) was also observed at the same dose as
maternal toxicity (ocular opacity) in the DNT study.  Last, offspring
toxicity (ocular toxicity) was observed at the same as or higher doses
than parental toxicity (thyroid effects) in the 2-generation rat
reproductive toxicity study.

The pyrasulfotole risk assessment team recommends that the 10X FQPA SF
for increased susceptibility be reduced to 1X for all exposure
scenarios.  This recommendation is based on the following
considerations:

The toxicology database is complete.

There are no residual uncertainties concerning pre- and postnatal
toxicity.  Clear NOAELs were established for all exposure scenarios and
these are considered protective of the offspring susceptibility observed
in the rabbit developmental toxicity study.  The concern for increased
susceptibility seen in rabbit developmental toxicity study is low
because a) there is well established developmental NOAEL in the rabbit
developmental toxicity study in rabbits protecting fetuses from skeletal
anomalies/variations, b) the increased susceptibility was not seen in
rat developmental toxicity study, developmental neurotoxicity study in
rats and two generation reproduction study in rats, c) the NOAEL of the
study chosen for the chronic RfD is 10x lower than the rabbit
developmental toxicity study NOAEL (10 mg/kg/day).

There are no residual uncertainties with respect to exposure data.

The dietary food exposure assessment utilizes proposed tolerance-level
residues and 100% CT information for all proposed commodities.  By using
this screening-level assessment, the acute and chronic exposures/risks
will not be underestimated.

The dietary drinking water assessment (Tier 1 estimates) utilizes values
generated by model and associated modeling parameters which are designed
to provide conservative, health protective, high-end estimates of water
concentrations.

There are no registered or proposed uses of pyrasulfotole which would
result in residential exposure.

3.4	Hazard Identification and Toxicity Endpoint Selection  TC "3.4
Hazard Identification and Toxicity Endpoint Selection" \f C \l "2"

A summary of the toxicological endpoints and doses chosen for the
relevant exposure scenarios for dietary and occupational human health
risk assessments is provided in Tables 3.4.12a and 3.4.12b.  The
conventional interspecies extrapolation (10X) and intraspecies variation
(10X) uncertainty factors were applied for all exposure scenarios.  The
FQPA SF for increased susceptibility was reduced to 1X for all exposures
scenarios.

3.4.1	Acute Reference Dose (aRfD)  TC "3.4.1	Acute Reference Dose
(aRfD)" \f C \l "3"

The aRfD for the general U.S. population, including infants and
children, was established based on adverse effects observed in the
developmental neurotoxicity study in the rat.  Relevant toxicological
effects that could be the result of a single dose to the fetus during
gestation were delayed preputial separation (males), decreased cerebrum
length (PND 21 females), and decreased cerebellum height (PND 21 males).
 These adverse effects were observed in offspring at the
lowest-observable-adverse-effect-level (LOAEL) of 37 mg/kg/day (NOAEL =
3.8 mg/kg/day).  The aRfD/aPAD is 0.038 mg/kg.  This study and endpoint
are the most appropriate for the population of concern following a
single oral exposure.

3.4.2	Chronic Reference Dose (cRfD)  TC "3.4.2	Chronic Reference Dose
(cRfD)" \f C \l "3"

The cRfD was established based on ocular toxicity observed in the
combined chronic toxicity/carcinogenicity study in the rat.  Adverse
effects included corneal opacity, neovascularization of the cornea,
inflammation of the cornea, regenerative corneal hyperplasia, corneal
atrophy, and/or retinal atrophy in both sexes, and hepatocellular
hypertrophy along with increased serum cholesterol in males at the LOAEL
of 10/14 mg/kg/day (M/F) (NOAEL = 1.0 mg/kg/day).  This study provided
the critical effect across three chronic toxicity studies in the rat,
mouse, and dog.  The 2-generation reproduction study is a co-critical
study.  Altered colloid and/or pigment deposition were observed in the
thyroid of parental animals at the LOAEL of 2.5/3.1 mg/kg bw/day (M/F).
Application of a 3X uncertainty factor for extrapolation of a LOAEL to a
NOAEL, based on minimal severity of the effect at the LOAEL, would lead
to a point of departure of 1 mg/kg/day.  The cRfD/cPAD is 0.01
mg/kg/day.

3.4.3	Incidental Oral Exposure (Short- and Intermediate-Term)  TC "3.4.3
Incidental Oral Exposure (Short- and Intermediate-Term)" \f C \l "3"

There are no residential uses proposed for pyrasulfotole at this time.
If residential uses are proposed in the future, the effects of concern
that are relevant to the selection of the short- and intermediate-term
incidental oral doses are corneal opacity and/or corneal
neovascularization that were observed in F1- and F2-generation offspring
at 26.3/32.6 mg/kg bw/day (M/F) (LOAEL) in the 2-generation reproduction
toxicity study in the rat (NOAEL = 2.5 mg/kg/day).  The study length is
appropriate for the durations of exposure, namely, 1-30 days
(short-term) and 1-6 months (intermediate-term), and the observed
adverse effects are among the primary toxic effects observed in the
database.

3.4.4	Dermal Absorption  TC "3.4.4	Dermal Absorption" \f C \l "3"

A dermal absorption study is not available in the database.  Based on
the submitted toxicology data, an estimate of dermal absorption was
made.  The LOAEL from the 28-day dermal toxicity study (100 mg/kg/day)
was compared to the parental LOAEL from the oral 2-generation
reproductive toxicity study (2.5 mg/kg/day).  Alteration of thyroid
colloid was observed in both studies in rats.  The dermal absorption
factor was estimated to be 2.5%.  Because exposure in the 2-generation
reproduction study is much longer than in the dermal study, the study
durations are not equivalent, and an in vivo dermal penetration study is
required to confirm the estimated dermal absorption factor.

3.4.5	Dermal Exposure (Short- and Intermediate-Term)  TC "3.4.5	Dermal
Exposure (Short- and Intermediate-Term)" \f C \l "3"

There are no residential uses proposed for pyrasulfotole at this time.
The effects of concern that are relevant to the selection of the short-
and intermediate-term dermal doses for occupational risk assessment are
focal degeneration of the pancreas and alteration of thyroid colloid
that were observed at 100 mg/kg bw/day (M/F) (LOAEL) in the dermal
toxicity study in the rat (NOAEL = 10 mg/kg/day).  This study is
considered protective of exposure to pregnant female workers (worst-case
scenario), since the dermal NOAEL (10 mg/kg/day) is much less than the
dermal equivalent dose (152 mg/kg/day) calculated for the DNT study
(NOAEL = 3.8 mg/kg/day; used to calculate aRfD) using the estimated
dermal absorption factor (2.5%).  An MOE of >100 is adequate.

3.4.6	Dermal Exposure (Long-Term)  TC "3.4.6	Dermal Exposure
(Long-Term)" \f C \l "3"

There are no residential uses proposed for pyrasulfotole at this time.
A long-term dermal exposure endpoint was chosen based on the LOAEL from
the chronic oral toxicity/carcinogenicity study in the rat.  A long-term
dermal toxicity study was not available. Ocular toxicity (corneal
opacity, neovascularization of the cornea, inflammation of the cornea,
regenerative corneal hyperplasia, corneal atrophy, and/or retinal
atrophy), and mild hepatotoxicity (hepatocellular hypertrophy along with
increased serum cholesterol) were observed at the LOAEL of 10/14
mg/kg/day (M/F) (NOAEL = 1 mg/kg/day).  The NOAELs are the lowest in the
database following long-term oral animal exposure, and the study
duration is ideal for the duration of exposure.  The 2-generation
reproduction study is a co-critical study for this exposure scenario.
Altered colloid and/or pigment deposition were observed in the thyroid
of parental animals at the LOAEL of 2.5/3.1 mg/kg bw/day (M/F).
Application of a 3X uncertainty factor for extrapolation of a LOAEL to a
NOAEL, based on minimal severity of the effect at the LOAEL, would lead
to a point of departure of 1 mg/kg/day.  An MOE of >100 is considered
protective.

3.4.7	Inhalation Exposure (All Durations)  TC "3.4.7	Inhalation Exposure
(Short- and Intermediate-Term)" \f C \l "3"

There are no residential uses proposed for pyrasulfotole at this time.
The effects of concern that are relevant to the selection of the short-,
intermediate-, and long-term

inhalation doses for occupational risk assessment are ocular toxicity
(corneal opacity, neovascularization of the cornea, inflammation of the
cornea, regenerative corneal hyperplasia, corneal atrophy, and/or
retinal atrophy), and mild hepatotoxicity (hepatocellular hypertrophy
along with increased serum cholesterol) that were observed at 10/14
mg/kg bw/day (M/F) (LOAEL) in the combined chronic
toxicity/carcinogenicity study in the rat (NOAEL = 1 mg/kg/day).  The
2-generation reproduction study is a co-critical study.  Altered colloid
and/or pigment deposition were observed in the thyroid of parental
animals at the LOAEL of 2.5/3.1 mg/kg bw/day (M/F).  Application of a 3X
uncertainty factor for extrapolation of a LOAEL to a NOAEL, based on
minimal severity of the effect at the LOAEL, would lead to a point of
departure of 1 mg/kg/day.  The studies are considered appropriate,
because the effects were observed in adult animals, and provide the
lowest point of departure in the database.  An MOE >100 is considered
adequate.  One hundred percent oral equivalent inhalation absorption is
assumed in the absence of inhalation absorption data.

3.4.9	Level of Concern for Margin of Exposure  TC "3.4.9	Level of
Concern for Margin of Exposure" \f C \l "3"

Table 3.4.9.  Summary of Levels of Concern for Occupational (Worker)
Exposure Risk Assessment.

Route	Short-Term (1-30 Days)	Intermediate-Term (1-6 Months)	Long-Term
(>6 Months)

Dermal	<100	<100	<100

Inhalation	<100	<100	<100

3.4.10	Recommendation for Aggregate Exposure Risk Assessments  TC
"3.4.10	Recommendation for Aggregate Exposure Risk Assessments" \f C \l
"3"

For oral exposure, dietary and drinking water exposures were combined.
For occupational exposure dermal and inhalation exposure were combined
since the effects of concern are the same and identified from the same
study.

3.4.11	Classification of Carcinogenic Potential  TC "3.4.11
Classification of Carcinogenic Potential" \f C \l "3"

Pyrasulfotole has been classified by the HED CARC as having
“Suggestive Evidence of Carcinogenic Potential,” based on increased
incidences of corneal tumors in male rats at the highest dose tested
(2500 ppm) in the chronic toxicity/carcinogenicity study in rat and
urinary bladder transitional cell tumors in male and female mice at the
highest dose tested (4000 ppm) in the mouse carcinogenicity study.
Quantification of carcinogenic potential is not required.  The chronic
RfD of 0.01 mg/kg/day, based on the rat chronic toxicity/carcinogenicity
study (NOAEL = 25 ppm [1 mg/kg/day] and LOAEL of 250 ppm [10 mg/kg/day])
would be protective of both non-cancer and potential cancer precursor
effects.

3.4.12	Summary of Toxicological Doses and Endpoints for Pyrasulfotole
for Use in Human-Health Risk Assessments  TC "3.4.12	Summary of
Toxicological Doses and Endpoints for Pyrasulfotole for Use in
Human-Health Risk Assessments" \f C \l "3"

Table 3.4.12a  Summary of Toxicological Doses and Endpoints for
Pyrasulfotole for Use in Dietary and Non-Occupational Human Health Risk
Assessments.  There are no residential uses proposed for pyrasulfotole
at this time.

Exposure Scenario	Point of Departure	Uncertainty/FQPA Safety Factors
RfD, PAD, LOC for Risk Assessment	Study and Relevant Toxicological
Effects

Acute Dietary (All populations)	NOAEL = 3.8

mg/kg/day	UFA = 10X

UFH = 10X

UFFQPA = 1X 	aRfD = aPAD = 0.038 mg/kg/day	Developmental neurotoxicity
(rat; dietary) Offspring LOAEL = 37 mg/kg/day based on delayed preputial
separation (males), decreased cerebrum length (PND 21 females), and
decreased cerebellum height (PND 21 males).

Chronic Dietary (All populations)	NOAEL = 1.0

mg/kg/day	UFA = 10X

UFH = 10X

UFFQPA = 1X	cRfD = cPAD = 0.01mg/kg/day	Combined chronic
toxicity/carcinogenicity (rat; dietary) LOAEL = 10/14 mg/kg/day (M/F)
based on corneal opacity, neovascularization of the cornea, inflammation
of the cornea, regenerative corneal hyperplasia, corneal atrophy, and/or
retinal atrophy (both sexes), and hepatocellular hypertrophy along with
increased serum cholesterol (males).1

Incidental Oral

Short- and Intermediate-Term (1-30 days and 1-6 months)	NOAEL = 2.5

mg/kg/day	UFA = 10X

UFH = 10X

UFFQPA = 1X

	No residential uses proposed.	Reproduction and fertility effects (rat;
dietary) Offspring LOAEL = 26.3/32.6 mg/kg bw/day [M/F] based on corneal
opacity and/or corneal neovascularization (F1 and F2 generations).

Dermal

Short- and Intermediate- Term (1-30 days and 1-6 months)	NOAEL = 10

mg/kg/day

	UFA = 10X

UFH = 10X

UFFQPA = 1X

	No residential uses proposed.	28-day dermal toxicity (rat) LOAEL = 100
mg/kg bw/day [M/F] based on focal degeneration of pancreas (both sexes)
and alteration of thyroid colloid (males)

Dermal

Long-Term (>6 months)	NOAEL = 1.0

mg/kg/day

Estimated dermal absorption factor = 2.5%	UFA = 10X

UFH = 10X

UFFQPA = 1X	No residential uses proposed.	Combined chronic
toxicity/carcinogenicity (rat; dietary) LOAEL = 10/14 mg/kg/day (M/F)
based on corneal opacity, neovascularization of the cornea, inflammation
of the cornea, regenerative corneal hyperplasia, corneal atrophy, and/or
retinal atrophy (both sexes), and hepatocellular hypertrophy along with
increased serum cholesterol (males).

Inhalation

(All durations)	NOAEL = 1.0

mg/kg/day

100% inhalation assumed	UFA = 10X

UFH = 10X

UFFQPA = 1X	No residential uses proposed.	Combined chronic
toxicity/carcinogenicity (rat; dietary) LOAEL = 10/14 mg/kg/day (M/F)
based on corneal opacity, neovascularization of the cornea, inflammation
of the cornea, regenerative corneal hyperplasia, corneal atrophy, and/or
retinal atrophy (both sexes), and hepatocellular hypertrophy along with
increased serum cholesterol (males).

Cancer (oral, dermal, inhalation)	Classification:  “Suggestive
Evidence of Carcinogenic Potential” based on increased incidences of
corneal tumors in male rats (oral carcinogenicity study) and urinary
bladder tumors in male and female mice (oral carcinogenicity study).

Abbreviations: UF = uncertainty factor, UFA = extrapolation from animal
to human (interspecies), UFH = potential variation in sensitivity among
members of the human population (intraspecies), UFFQPA = FQPA Safety
Factor, NOAEL = no observed adverse effect level, LOAEL = lowest
observed adverse effect level, RfD = reference dose (a = acute, c =
chronic), PAD = population adjusted dose, MOE = margin of exposure, LOC
= level of concern.

1 The cRfD was harmonized across American (USEPA), Canadian (PMRA), and
Australian (APVMA) regulatory agencies based on ocular toxicity observed
in the combined chronic toxicity/carcinogenicity study in rats.

Table 3.4.12b  Summary of Toxicological Doses and Endpoints for
Pyrasulfotole for Use in Occupational Human Health Risk Assessments

Exposure Scenario	Point of Departure	Uncertainty/FQPA Safety Factors
RfD, PAD, Level of Concern for Risk Assessment	Study and Toxicological
Effects

Dermal

Short- and Intermediate- Term (1-30 days and 1-6 months)	NOAEL = 10

mg/kg/day

	UFA = 10X

UFH = 10X

	Occupational LOC for MOE < 100	28-day dermal toxicity (rat) LOAEL = 100
mg/kg bw/day [M/F] based on focal degeneration of pancreas (both sexes)
and alteration of thyroid colloid (males)

Dermal

Long-Term (>6 months)	NOAEL = 1.0

mg/kg/day

Estimated dermal absorption factor = 2.5%	UFA = 10X

UFH = 10X	Occupational LOC for MOE < 100	Combined chronic
toxicity/carcinogenicity (rat; dietary) LOAEL = 10/14 mg/kg/day (M/F)
based on corneal opacity, neovascularization of the cornea, inflammation
of the cornea, regenerative corneal hyperplasia, corneal atrophy, and/or
retinal atrophy (both sexes), and hepatocellular hypertrophy along with
increased serum cholesterol (males).

Inhalation

(All durations)	NOAEL = 1.0

mg/kg/day

100% inhalation assumed	UFA = 10X

UFH = 10X	Occupational LOC for MOE < 100	Combined chronic
toxicity/carcinogenicity (rat; dietary) LOAEL = 10/14 mg/kg/day (M/F)
based on corneal opacity, neovascularization of the cornea, inflammation
of the cornea, regenerative corneal hyperplasia, corneal atrophy, and/or
retinal atrophy (both sexes), and hepatocellular hypertrophy along with
increased serum cholesterol (males).

Cancer (oral, dermal, inhalation)	Classification:  “Suggestive
Evidence of Carcinogenic Potential” based on increased incidences of
corneal tumors in male rats (oral carcinogenicity study) and urinary
bladder tumors in male and female mice (oral carcinogenicity study).

Abbreviations: UF = uncertainty factor, UFA = extrapolation from animal
to human (interspecies), UFH = potential variation in sensitivity among
members of the human population (intraspecies), UFFQPA = FQPA Safety
Factor, NOAEL = no observed adverse effect level, LOAEL = lowest
observed adverse effect level, RfD = reference dose (a = acute, c =
chronic), PAD = population adjusted dose, MOE = margin of exposure, LOC
= level of concern.

3.5	Endocrine Disruption  TC "3.5	Endocrine Disruption" \f C \l "2"

EPA is required under the FFDCA, as amended by FQPA, to develop a
screening program to determine whether certain substances (including all
pesticide active and other ingredients) “may have an effect in humans
that is similar to an effect produced by a naturally occurring estrogen,
or other such endocrine effects as the Administrator may designate.”
Following recommendations of its Endocrine Disruptor and Testing
Advisory Committee (EDSTAC), EPA determined that there was a scientific
basis for including, as part of the program, the androgen and thyroid
hormone systems, in addition to the estrogen hormone system.  EPA also
adopted EDSTAC’s recommendation that the Program include evaluations
of potential effects in wildlife.  For pesticide chemicals, EPA will use
FIFRA and, to the extent that effects in wildlife may help determine
whether a substance may have an effect in humans, FFDCA authority to
require the wildlife evaluations.  As the science develops and resources
allow, screening of additional hormone systems may be added to the
Endocrine Disruptor Screening Program (EDSP).

When additional appropriate screening and/or testing protocols being
considered under the Agency’s EDSP have been developed, pyrasulfotole
may be subjected to further screening and/or testing to better
characterize effects related to endocrine disruption.

4.0	Public Health and Pesticide Epidemiology Data  TC "4.0	Public Health
and Pesticide Epidemiology Data" \f C \l "1"

No public health/epidemiology data were used in developing this risk
assessment.  Since pyrasulfotole is a new a.i, data are not available.

5.0	Dietary Exposure/Risk Characterization  TC "5.0	Dietary
Exposure/Risk Characterization" \f C \l "1"

The residue chemistry data submitted in support of the proposed uses
were summarized in the HED-memorandum dated 06/08/07 (J. Tyler; DP#
333412).  The drinking water assessment was provided by EFED in a memo
dated 1/18/07 (M. Echeverria; DP# 330817).  The acute and chronic
dietary exposure assessments were completed in a HED-memorandum dated
06/08/07 (J. Tyler, DP# 333435).

5.1	Pesticide Metabolism and Environmental Degradation  TC "5.1
Pesticide Metabolism and Environmental Degradation" \f C \l "2"

5.1.1	Metabolism in Primary Crops  TC "5.1.1	Metabolism in Primary
Crops" \f C \l "3"

The available wheat metabolism studies (a phenyl-labeled study, a
pyrazole-labeled study, and a phenyl-labeled study comparing the nature
of the residue in spring wheat with and without the safener) are
adequate, and indicate that the metabolism of pyrasulfotole in spring
wheat involves the demethylation and subsequent glucosylation of the
parent compound, yielding pyrasulfotole-desmethyl-O- glucoside.  There
was also cleavage of the complete pyrazole moiety resulting in the
pyrasulfotole-benzoic acid metabolite as detected by the phenyl-label
study and a polar fraction (p1) formed from the pyrazole-label study.
Fraction p1 was characterized as being natural or incorporated into the
matrix.

Following spray applications of either phenyl- and pyrazole-labeled
pyrasulfotole at a nominal rate of 0.089 lb ai/A (~2x maximum proposed
application rate), total radioactive residues (TRR) levels were
0.44-0.47 ppm in forage, 0.06-0.18 ppm in hay, 0.38-0.55 ppm in straw,
and 0.03-0.30 ppm in grain.  In the phenyl-labeled study, the
predominant residue was pyrasulfotole-benzoic acid in all wheat matrices
with levels increasing as the plant matured (24.1-89.5% of the TRR;
0.11-0.35 ppm).  Pyrasulfotole-desmethyl-O-glucoside was also a major
component in wheat forage and hay, and a minor component in straw.  In
the pyrazole-labeled study, pyrasulfotole-desmethyl-O-glucoside was the
only metabolite identified in forage, hay, straw (21.7-43.0% of the TRR;
0.015-0.20 ppm), and grain (0.7% of the TRR; <0.001 ppm).  A polar
fraction, p1, was a major part of the residue in hay (20.9% of the TRR;
0.01 ppm), straw (10.9% of the TRR; 0.04 ppm), and grain (11.2% of the
TRR; 0.003 ppm).  Several unknown metabolite fractions of varying
polarity were detected in wheat matrices, none of them exceeding 7.7% of
the TRR (0.04 ppm).

Following a spray application of either phenyl-labeled pyrasulfotole at
a nominal rate of 0.089 lb ai/A (2x maximum proposed application rate)
or phenyl-labeled pyrasulfotole with the safener mefenpyr-diethyl, the
TRR levels were 2.40-2.44 ppm in forage, 3.12-3.14 ppm in hay, 2.44-2.90
ppm in straw, and 0.16-0.24 ppm in grain, indicating that the overall
distribution of the radioactive residues was quantitatively similar to
wheat with and without safener.  The predominant residue in wheat
forage, hay and straw was comprised of the metabolites
pyrasulfotole-benzoic acid (16.3-37.2% of the TRR; 0.39-1.06 ppm) and
pyrasulfotole-desmethyl-O-glucoside (19.6-43.5% of the TRR; 0.49-1.16
ppm).  Minor components were pyrasulfotole (4.4-7.3% of the TRR;
0.13-0.18 ppm), and pyrasulfotole-sulfinyl-lactate (3.8-9.6% of the TRR;
0.09-0.28 ppm).  In grain, pyrasulfotole-benzoic acid was the only
residue identified (97.6-97.7% of the TRR; 0.15-0.23 ppm).

5.1.2	Metabolism in Rotational Crops  TC "5.1.2	Metabolism in Rotational
Crops" \f C \l "3"

The submitted confined rotational crop study is adequate, and indicates
that the metabolic breakdown of pyrasulfotole involves the cleavage of
the complete pyrazole moiety yielding the benzoic acid metabolite.  In
rotational crops, the predominant residue is the pyrasulfotole-benzoic
acid metabolite.

Wheat (small grain), Swiss chard (leafy vegetable), and turnips (root
crop) were planted approximately 120 days and 300 days (wheat only)
following an application of either phenyl- or pyrazole-labeled
pyrasulfotole to soil in large troughs at a rate of 0.073 lb ai/A (2.2x
the maximum proposed application rate).  Total residues amounting to
27.0 to 91.3% of the TRR were identified in rotational crop matrices
following application of phenyl-labeled pyrasulfotole.  Total identified
residues were 3 to 9% of the TRR (<0.001-0.002 ppm) following
application of pyrazole-labeled pyrasulfotole.  A number of components
were characterized as acetonitrile (ACN)/H2O soluble.  Nonextractable
residues following extraction procedures accounted for 3.1 to 29% of the
TRR (0.001-0.008 ppm) in phenyl-label samples, and 40 to 47% of the TRR
(0.006-0.008 ppm) in pyrazole-label samples.

The predominant residue was identified as pyrasulfotole-benzoic acid in
all wheat matrices (27.0-91.3% of the TRR; 0.004-0.078 ppm) at 120-days
after treatment (DAT) and 301-DAT when dosed with phenyl-labeled
pyrasulfotole.  Pyrasulfotole-benzoic acid was not identified in the
120-DAT wheat straw and hay following application of pyrazole-labeled
pyrasulfotole.  Pyrasulfotole was identified in 120-DAT wheat grain and
301-DAT wheat hay samples (0.9-2.0% of the TRR; 0.001 ppm) for the
phenyl-labeled study.  Pyrasulfotole was the only identified component
in the 120-DAT wheat hay and straw samples (3-9% of the TRR;
<0.001-0.002 ppm) for the pyrazole-labeled study.  Multiple components
were characterized as ACN/H2O soluble or remaining solid phase
extraction fractions in wheat matrices for the phenyl-labeled study
(3.9-47.2% of the TRR; 0.001-0.025 ppm) and the pyrazole-labeled (37-50%
of the TRR; 0.003-0.013 ppm).

5.1.3	Metabolism in Livestock  TC "5.1.3	Metabolism in Livestock" \f C
\l "3"

The nature of the pyrasulfotole residues in livestock is understood
based on the acceptable phenyl- and pyrazole-labeled lactating goat and
laying hen metabolism studies.  The goat study indicates that the
metabolism of pyrasulfotole in lactating goats involved either
N-demethylation of pyrasulfotole to produce pyrasulfotole-desmethyl, or
oxidation of pyrasulfotole to produce pyrasulfotole-hydroxymethyl.  The
hen study indicates that the metabolism pyrasulfotole in laying hens
involved the N-demethylation of pyrasulfotole to yield the
pyrasulfotole-desmethyl metabolite.

In the lactating goat studies, following three consecutive days of
dosing with [14C]pyrasulfotole at levels equivalent to 51.2 [phenyl
label; 130x the maximum theoretical dietary burden (MTDB) to dairy
cattle] or 28.1 ppm (pyrazole label; 72x the MTDB to dairy cattle) in
the diet, TRR levels were highest in liver (1.447-1.723 ppm) and were
considerably lower in kidney (0.269-0.533 ppm), fat (0.008-0.010), and
muscle (0.007-0.010 ppm.)  Residues in milk increased slightly over time
to 0.017-0.044 ppm by Day 3 (p.m.).  In the phenyl-labeled study, the
majority of the residue was comprised of pyrasulfotole in muscle (80.2%
of the TRR; 0.008 ppm), kidney (99.6% of the TRR; 0.532 ppm), liver
(95.5% of the TRR; 1.411 ppm) and milk (82.7% of the TRR; 0.014 ppm).
Lesser amounts were identified as pyrasulfotole-desmethyl metabolite in
milk (11.7% of the TRR, 0.002 ppm), and hydroxymethyl pyrasulfotole in
muscle (8.3% of the TRR; 0.001 ppm) and milk (4.4% of the TRR; 0.002
ppm).  In the pyrazole-labeled study, pyrasulfotole was identified as
the major residue in the liver (93.3% of the TRR, 1.603ppm) and kidney
(92.4% of the TRR, 0.249 ppm).  Additionally, two minor metabolites were
identified/characterized from the extractable liver residue as
pyrasulfotole-desmethyl (1.4% of the TRR, 0.025 ppm), and an
unidentified polar metabolite (1.7% of the TRR, 0.030 ppm).  In milk,
the predominant residue was pyrasulfotole (38.8% of the TRR, 0.017 ppm)
with lesser amounts of three unknown polar compounds, none of which
exceeded 0.006 ppm.  In both radiolabeled studies, the majority of the
radioactivity (>67%) was recovered in urine and feces (phenyl >67%, and
pyrazole >92%), with less than 1.15% (phenyl) and 0.1% (pyrazole) in
milk, and 1.12% (phenyl) and 0.925% (pyrazole) in tissues.

In the laying hen studies, following 14 consecutive days of dosing at
levels equal to 8.6 (phenyl label; 150x the MTDB to poultry) or 10.5 ppm
(pyrazole label; 180x the MTDB to poultry) pyrasulfotole equivalents in
the diet, TRR levels were highest in liver (1.285-1.560 ppm) and were
considerably lower in fat (0.015-0.066), muscle (0.020-0.038 ppm.), and
eggs (<0.001-0.004 ppm).  The predominant residue in muscle (95.5% of
the TRR; 0.036 ppm), fat (97.1% of the TRR; 0.064 ppm) and liver (93.3%
of the TRR; 1.456 ppm) was pyrasulfotole.  Pyrasulfotole-desmethyl was a
minor metabolite in muscle (2.2% o the TRR; 0.001 ppm), fat (1.8% of the
TRR; 0.001 ppm) and liver (6.5% of the TRR; 0.101 ppm).  In both
radiolabeled studies, the majority of the radioactivity (phenyl >97%,
and pyrazole >85%) was recovered in urine and feces, with less than 0.4%
(phenyl) and 0.2% (pyrazole) in tissues and eggs.

5.1.4	Analytical Methodology  TC "5.1.4	Analytical Methodology" \f C \l
"3"

An adequate high-performance liquid chromatography (HPLC)/MS/MS method
(Method AI-001-P04-1) is available for collecting data on residues of
pyrasulfotole and its metabolite pyrasulfotole-desmethyl in/on plant
commodities.  The limit of quantitation (LOQ) is 0.010 ppm for each
analyte.  Method AI-001-P04-1, which is also the proposed enforcement
method for plant commodities, has been adequately radiovalidated and
undergone a successful ILV trial.  The proposed method was forwarded to
the ACB/BEAD for a Memo, J. Tyler, 1/30/07; DP# 335558).  ACB reviewed
the proposed enforcement method data without an ACB validation (Memo, C.
Stafford, 6/7/07; D335559).  Provided the method is revised as specified
in the ACB review, Method AI-001-P04-01 is a suitable enforcement method
for determination of pyrasulfotole and pyrasulfotole-desmethyl in crop
matrices.  In particular, the ACB determined that the plant method does
not meet general requirement as a confirmatory method since only one
MS/MS ion transition is documented.  The ACB recommends that the
petitioner provide information for a second MS/MS ion transition to
provide a confirmation of analyte identities.  If two ion transitions
are not available, HED recommends that the petitioner provide an
alternate chromatographic column and/or mobile-phase combination to add
an additional degree of specificity and further reduce the possibility
of false positive residues.

The HPLC-MS/MS method (Method AI-004-A05-01) is adequate for collecting
data on pyrasulfotole in livestock tissues, including milk, matrices.
However, based on the results of the livestock metabolism studies, the
residues of concern in livestock are pyrasulfotole and
pyrasulfotole-desmethyl for tolerance and risk assessment purposes.
Therefore, the petitioner should submit a ruminant analytical
enforcement method to determine residues of pyrasulfotole and
pyrasulfotole-desmethyl as well as adequate radiovalidation and ILV
data.  Upon submission, the method will be forwarded to ACB/BEAD for a
PMV trial.  It should be noted that ACB believes that the proposed
analytical enforcement method will work for pyrasulfotole-desmethyl
(e-mail from C. Stafford to J. Tyler; 3/3/007).  Therefore, HED
recommends for a conditional registration until an updated method is
submitted.

Pyrasulfotole and the metabolite pyrasulfotole-desmethyl were subjected
to analysis by selected Protocols of the Food and Drug Administration
(FDA) Pesticide Analytical Manual, Volume I (PAM I), third edition.  The
results indicate that pyrasulfotole is partially recovered through
Protocol B, and completely recovered through Protocol C module DG-17.
Pyrasulfotole-desmethyl was not recovered through any of the Protocols.
The report has been forwarded to FDA for inclusion in PAM I (Memo, J.
Tyler, 01/30/07; D335562).

5.1.5	Environmental Degradation  TC "5.1.5	Environmental Degradation" \f
C \l "3"

Pyrasulfotole is expected to be persistent and mobile to moderately
mobile in the environment.  Major routes of dissipation include
microbial degradation in soils, formation of non-extractable residues in
soils and sediments, and dilution.

Under aerobic conditions pyrasulfotole degraded in 3 soils (loamy sand,
silt loam, sandy loam) according to an apparent bi-phasic pattern with
observed DT50s ranging from 4-65 days and observed DT90s ranging from
>120->358 days.  A 2-compartment, 4-parameter exponential model, also
known as Double First Order Parallel (DFOP), was used to fit the data
and resulted in modeled DT50s ranging from 6-63 days and DT90s ranging
from 208-1424 days.  Degradation products included pyrasulfotole-benzoic
acid, CO2 and non-extractable residues.  Non-extractable residues were
identified at maximums of 35-62% of applied radioactivity in the 3
soils.  The non-extractable residues are uncharacterized and it is
uncertain whether they consist of degradates of risk concern.  Under
sterile conditions, however, the formation of non-extractable residues
(as well as the formation of CO2 and the benzoic acid degradate) were
negligible.  In terrestrial field dissipation studies, pyrasulfotole
dissipated from the whole soil profile with modeled (DFOP) DT90s ranging
from 44-531 days and the amount of parent pyrasulfotole carry over to
the following growing season ranged from 4.7 to 37%.

In aquatic systems, pyrasulfotole is stable to hydrolysis and
photolysis.  In aerobic aquatic metabolism studies, pyrasulfotole
partitioned to the sediment and formed non-extractable residues but
there was no evidence of degradation.  Pyrasulfotole is considered
stable to microbial degradation in aquatic systems.  Under anaerobic
conditions pyrasulfotole is also stable.

Batch equilibrium studies resulted in organic carbon sorption
coefficients (Koc) ranging from 20-345 ml/goc with a median value of 68
ml/goc.  In terrestrial field dissipation studies pyrasulfotole showed
variable downward migration in the soil profile under bare soil
conditions.  In some studies pyrasulfotole was confined to 0-15 cm
whereas in others it was detected at quantifiable levels as deep as
75-90 cm.  Since pyrasulfotole has a Kd less than 5 in most soils and is
persistent (hydrolysis half-life greater than 25 weeks, photolysis
half-life greater than 1 week, aerobic soil metabolism half-life greater
than 2-3 weeks), not volatile (Henry’s Law constant less than 10-2
atm*m-3/mol), and shows movement to 45 cm during some field dissipation
studies, there is indication for potential groundwater contamination
(Cohen 1984).  Depending on soil, site and meteorological conditions
pyrasulfotole may be transported off-site to drinking water sources via
runoff, leaching and spray drift.

5.1.6	Comparative Metabolic Profile  TC "5.1.6	Comparative Metabolic
Profile" \f C \l "3"

Pyrasulfotole is readily absorbed through the rat gastrointestinal tract
and is primarily excreted in the urine (73-75% via oral dose, and 87-91%
via intravenous dose) and feces (31-32% via oral dose, and 8-10% TRR via
intravenous dose) by 48-52 hours.  The tissue burden is low, with <2% of
the dose remaining in the carcass and tissues at sacrifice.  Following
both oral and intravenous administration, most of the dose was excreted
unchanged as pyrasulfotole.  Hydroxymethyl pyrasulfotole,
pyrasulfotole-desmethyl, and pyrasulfotole-benzoic acid were observed as
minor metabolites in the urine and feces.

The metabolism of pyrasulfotole in primary plants and livestock appears
to be similar to its metabolism in rats.  The primary metabolic pathway
in animals (rats, goats and hens) involves the N-demethylation of
pyrasulfotole to produce pyrasulfotole-desmethyl.  In plants (primary
crops), formation of pyrasulfotole-desmethyl via N-demethylation was
also a major metabolic pathway, followed by either glucosylation to
produce a pyrasulfotole-desmethyl-O-glucose conjugate or conjugation
with gluthathione to produce pyrasulfotole-sulfonyl-lactate.  Another
metabolic pathway in rats, primary crops and rotational crops involved
the cleavage of the pyrazole moiety resulting in pyrasulfotole-benzoic
acid.  Pyrasulfotole-benzoic acid was a major metabolite in rotational
crops, which was consistent with it also being the major metabolite in
soil degradation studies.  Another minor metabolic pathway in goats and
rats involved the hydroxylation of the pyrazole methyl group.

5.1.7	Toxicity Profile of Major Metabolites and Degradates  TC "5.1.7
Toxicity Profile of Major Metabolites and Degradates" \f C \l "3"

Little information is available on the toxicity of
pyrasulfotole-desmethyl.  However, based on the structural similarity of
the parent and the pyrasulfotole-desmethyl metabolite, and in the
absence of toxicological evidence to the contrary,
pyrasulfotole-desmethyl is assumed to be of comparable toxicity to the
parent.

≥ 250 mg/kg/day.  The clinical signs of toxicity were considered due
to daily boluses by gavage since they were not seen at much higher
dietary doses.  In addition, the pregnancy status of the animals may
have contributed to the observed results.

5.1.8	Pesticide Metabolites and Degradates of Concern  TC "5.1.8
Pesticide Metabolites and Degradates of Concern" \f C \l "3"

Table 5.1.8.  Summary of Metabolites and Degradates to be included in
Risk Assessment and Tolerance Expression.

Matrix	Residues included in Risk Assessment	Residues included in
Tolerance Expression

Plants	Primary Crop	Parent and Pyrasulfotole-desmethyl	Parent and
Pyrasulfotole-desmethyl

	Rotational Crop	Parent only	Parent only

Livestock	Ruminant	Parent and Pyrasulfotole-desmethyl	Parent and
Pyrasulfotole-desmethyl

	Poultry	Parent and Pyrasulfotole-desmethyl	Parent and
Pyrasulfotole-desmethyl

Drinking Water	Parent only	Not Applicable

Plants (Primary Crops):  For wheat, the pyrasulfotole risk assessment
team determined that the residues of concern in cereal grains for both
tolerance and risk assessment purposes are parent and the
pyrasulfotole-desmethyl metabolite.  This decision was based on the
following:

Pyrasulfotole-desmethyl-O-glucoside, the conjugated form of
pyrasulfotole-desmethyl, was seen in the available wheat metabolism
studies.

Wheat (without safener) study:  In the phenyl-labeled study,
pyrasulfotole-desmethyl-O-glucoside was a major component in wheat
forage (34.2% TRR; 0.152 ppm) and hay (10.4% TRR; 0.02 ppm); and a minor
component in straw (5.1% TRR; 0.03 ppm).  In the pyrazole-label study,
pyrasulfotole-desmethyl-O-glucoside was the only metabolite identified
in forage (43.4% TRR; 0.202 ppm), hay (25.4 TRR; 0.015 ppm), straw
(21.7% TRR, 0.08 ppm), and grain (0.7% TRR, <0.001 ppm).

Wheat (with and without safener) study:  In the phenyl-labeled study
with safener, pyrasulfotole-desmethyl-O-glucoside was a major component
in wheat forage (43.5% TRR; 1.04 ppm), hay (36.7% TRR; 1.16 ppm), and
straw (27.9% TRR, 0.81 ppm).  In the phenyl-label study without safener,
pyrasulfotole-desmethyl-O-glucoside was the major metabolite identified
in forage (30.2% TRR; 0.74 ppm), hay (25.7 TRR; 0.80 ppm), and straw
(19.6% TRR, 0.55 ppm).

Based on the structure similarity of the parent and the
pyrasulfotole-desmethyl metabolite, and in the absence of toxicological
evidence to the contrary, pyrasulfotole-desmethyl metabolite is assumed
to be of comparable toxicity to the parent.

Pyrasulfotole-desmethyl was seen in quantifiable levels in wheat
(forage, hay, and straw), barley (hay and straw), and oat (forage,
grain, hay and straw) in the submitted crop field trial studies.  In
addition, in the majority of the commodities, pyrasulfotole-desmethyl
was present at levels equal to or greater than the parent pyrasulfotole.

The proposed enforcement and data collection method, Method
AI-001-P04-01 is a HPLC-MS/MS method for residues of pyrasulfotole and
pyrasulfotole-desmethyl in crop matrices.

Although pyrasulfotole-benzoic acid was a major metabolite in the wheat
metabolism and wheat, barley and oat crop field trial studies, based on
available toxicology studies on pyrasulfotole-benzoic acid, the risk
assessment team determined that it is not of toxicological concern (see
rationale below).  Therefore, it was not included in the residue
definition for tolerance or risk assessment purposes for cereal grains.

Plants (Rotational Crops):  The pyrasulfotole risk assessment team
determined that the residue of concern in rotational crops for both
tolerance and risk assessment purposes is parent only.  This decision
was based on the results of the available confined rotational crop
study, which indicate that the metabolic breakdown of pyrasulfotole in
rotational crops involves the cleavage of the complete pyrazole moiety
yielding the benzoic acid metabolite.  Although pyrasulfotole-benzoic
acid was the predominant residue in all wheat matrices at 120-and
301-day PBI, based on available toxicology studies on
pyrasulfotole-benzoic acid, the risk assessment team determined that it
is not of toxicological concern (see rationale below).

Livestock:  The pyrasulfotole risk assessment team determined that the
residues of concern in livestock for both tolerance and risk assessment
purposes are parent and the pyrasulfotole-desmethyl metabolite.  This
decision was based on the following:

In available crop field trials, pyrasulfotole-desmethyl was one of the
major residues in livestock feed items; therefore, secondary residues to
livestock are likely to be pyrasulfotole-desmethyl instead of parent.

Although pyrasulfotole-benzoic acid was a major metabolite in the wheat,
barley and oat crop field trial studies, based on available toxicology
studies on pyrasulfotole-benzoic acid, the risk assessment team
determined that it is not of toxicological concern (see rationale
below).  Therefore, it was not included in the residue definition for
tolerance or risk assessment purposes for livestock commodities.

Drinking Water:  The pyrasulfotole risk assessment team determined that
the residue of concern in drinking water for risk assessment purposes is
parent only.  Although pyrasulfotole-benzoic acid was identified as the
only environmental degradate in the soil metabolism and terrestrial
field dissipation studies, based on available toxicology studies on
pyrasulfotole-benzoic acid, the risk assessment team determined that it
is not of toxicological concern (see rationale below); and, thus should
not be included in the drinking water assessment for pyrasulfotole.

Rationale for not including benzoic acid metabolite of pyrasulfotole as
metabolite of concern:  Although pyrasulfotole benzoic acid was a major
metabolite in wheat and rotational crops and a minor metabolite in rats
and drinking water, the pyrasulfotole risk assessment team determined
that it is not of toxicological concern.  This decision was based on the
results of several toxicology studies submitted for the benzoic acid
metabolite.  The following were observed in the submitted toxicology
studies:

No mortalities were observed in the acute oral toxicity study in the
rat.  The oral LD50 for male and female rats was >5000 mg/kg (Category
IV).

In separate 28-day and 90-day dietary toxicity studies in rats, no
toxicity was observed for the benzoic acid metabolite up to and
including the highest doses tested (1118/1269 and 769/952 mg/kg/day in
males/females, respectively), whereas toxicity was observed with the
parent compound in similar short-term studies in rats and dogs at much
lower doses (see Appendix A.2 for summary).

The benzoic acid metabolite was negative for mutagenicity and
clastogenicity in four separate genotoxicity studies.

No evidence of teratogenicity was observed in a developmental toxicity
study in the rat.  In the same study, decreased body weight gain and
food consumption and clinical signs of toxicity (salivation,
piloerection, red nasal discharge around the time of treatment) were
observed in dams at doses ≥ 250 mg/kg/day.   The clinical signs of
toxicity were considered due to daily boluses by gavage since they were
not seen at much higher dietary doses.  In addition, the pregnancy
status of the animals may have contributed to the observed results.

Based on the lack of mortality in the acute oral toxicity study (LD50
>5000 mg/kg), lack of toxicity in two short-term toxicity studies, lack
of developmental toxicity, questionable toxicity in pregnant dams, and
the lack of genotoxicity in four acceptable assays, the risk assessment
team recommended that the benzoic acid metabolite of pyrasulfotole not
be included in the residue definition for tolerance or risk assessment
purposes for any commodity.

5.1.9	Drinking Water Residue Profile  TC "5.1.9	Drinking Water Residue
Profile" \f C \l "3"

EFED provided Tier 1 EDWCs for surface and ground water which were
generated using FIRST and SCIGROW, respectively.  Based on the results
of these simulations, EFED recommends an acute surface water EDWC of 4.0
µg/L and a chronic EDWC of 2.8 µg/L for use in the human-health risk
assessment.  These recommendations are based on the use of pyrasulfotole
on cereal grains (wheat, barley, oats, and triticale) at an annual
application rate of 0.045 lb ai/A/year.  The recommended EDWC for
groundwater is 1.4 µg/L and is also based on the use of pyrasulfotole
on cereal grains at the previously stated rate.  Table 5.1.9 lists the
summary of estimated surface and groundwater EDWCs for pyrasulfotole.

Table 5.1.9.  Summary of Estimated Surface Water and Groundwater EDWCs
for Pyrasulfotole.

	Pyrasulfotole

	Surface Water Concentration (ppb)a	Groundwater Concentration (ppb)b

Acute	4.0	1.4

Chronic (non-cancer)	2.8	1.4

Chronic (cancer)	-	-

a From the Tier I FIRST model.  Input parameters are based on aerial
spray applications to small grains at a rate of 0.045 lb ai/A/year.

b From the SCI-GROW model assuming a maximum seasonal use rate of 0.045
lb ai/A, a Koc of 20 ml/gOC, and half-life of 226 days.

5.1.10	Food Residue Profile  TC "5.1.10	Food Residue Profile" \f C \l
"3"

The available crop field trial data on wheat, barley and oats on both
the SE06 and EC23 end-use products are classified as scientifically
acceptable for determination of the magnitude of residues for
pyrasulfotole and the metabolites pyrasulfotole-benzoic acid and
pyrasulfotole-desmethyl when treated with the end use products AE 017309
02 SE06 or AE 017309 03 + Bromo.  Although pyrasulfotole-benzoic acid
was a primary residue in most commodities, it was determined by the
pyrasulfotole risk assessment team to be not of toxicological concern;
and, therefore, should not be included in the tolerance expression for
small cereal grains.

In general, in wheat and barley, residues of pyrasulfotole and
pyrasulfotole-desmethyl appeared to be slightly higher following
application of the SE06 formulation.  In oats, the amount of each
analyte detected was essentially the same between formulations.  In
wheat, barley and oats, the highest residue levels were observed in/on
the hay samples and the lowest levels observed in/on the grain samples.
Available residue decline data on wheat, barley and oats indicate that
residues of pyrasulfotole and pyrasulfotole-desmethyl decreased with
time in forage and wheat hay, but decreased only slightly or remained
unchanged in straw and grain with increasing preharvest intervals.
There are adequate storage stability data to validate the storage
conditions and intervals of samples collected from the field trials.

For purposes of determining appropriate tolerance levels for the
proposed uses, individual pyrasulfotole and pyrasulfotole-desmethyl
residues were summed to yield a total residue value.  In many cases,
individual apparent residues were either <LOQ (<0.01 ppm) but > limit of
detection (>LOD; >0.005 ppm), or <LOD (0.005 ppm).  In cases where the
individual value (pyrasulfotole and/or pyrasulfotole-desmethyl) was <LOQ
(<0.01 ppm) but >LOD (>0.005 ppm), the actual value was used.  In cases
where an individual value (pyrasulfotole or pyrasulfotole-desmethyl) was
<LOD (<0.005 ppm), the LOD (0.005 ppm) was used.  The pyrasulfotole and
pyrasulfotole-desmethyl were then summed, and in cases where either
parent or desmethyl was <LOD, the data were considered to be censored.

Therefore, based on the percentage of censored data, appropriate
tolerances were either determined using either rounding up from the
highest-average field trial (HAFT) values from the respective crop field
trial studies, or the methodology formulated by the North America Free
Trade Agreement (NAFTA) Maximum Residue Level (MRL)/Tolerance
Harmonization Workgroup for calculating statistically based pesticide
tolerances for plant commodities based on field trial residue data.  For
wheat hay, wheat straw, barley hay, barley straw, oat forage, oat grain,
and oat hay, the appropriate tolerance levels were calculated using the
NAFTA MRL/Tolerance Harmonization Workgroup methodology.  For wheat
forage, wheat grain, and barley grain the appropriate tolerance levels
were calculated by rounding up from the HAFT values from the respective
crop field trial data.

The available crop field trial data indicate that the appropriate
tolerances for residues of pyrasulfotole and pyrasulfotole-desmethyl are
0.20 ppm in/on wheat, forage; 0.80 ppm in/on wheat, hay; 0.02 ppm in/on
wheat, grain; 0.20 ppm in/on wheat, straw; 0.30 ppm in/on barley, hay;
0.02 ppm in/on barley, grain; 0.20 ppm in/on barley, straw, 0.10 ppm
in/on oat, forage; 0.50 ppm in/on oat, hay; 0.08 ppm in/on oat, grain;
and 0.20 ppm in/on oat, straw.  In addition, the wheat, barley and oat
crop field trial data are adequate to support the proposed uses on rye
and triticale.  The available data indicate that the appropriate
tolerances for residues of pyrasulfotole and pyrasulfotole-desmethyl are
0.02 ppm in/on rye, grain; 0.20 ppm, in/on rye, straw; and 0.20 ppm
in/on rye, forage.  HED notes that the proposed tolerance for triticale,
grain is not needed as it is covered under the wheat, grain tolerance.

The results of the processing study indicate that residues of
pyrasulfotole and pyrasulfotole-desmethyl do not appear to concentrate
in wheat flour (0.26x), middling (0.38x), shorts (0.56x) and germ
(0.70x).  Total residues of pyrasulfotole and pyrasulfotole-desmethyl do
appear to concentrate in aspirated wheat grain fractions (33x), and
wheat bran (1.6x).  Based on these processing factors and a HAFT residue
of 0.011 ppm from the wheat field trials, a separate tolerance is not
needed for wheat, bran, but a tolerance should be established for
aspirated grain fractions at 0.40 ppm.  In addition, based on the
results of the processed food/feed data on wheat, HED concludes that
residues of pyrasulfotole and pyrasulfotole-desmethyl are not expected
to concentrate in pearled barley, barley flour, oat flour, groats/rolled
oats, and rye flour.  Therefore, tolerances on these processed
commodities are not needed.  Because the results of the processing study
indicate that residues concentrated in wheat bran, residues can be
expected to concentrate in barley bran, oat bran and rye bran as well.
Based on the 1.6x processing factor for wheat bran, and a HAFT residue
of 0.010 ppm from the barley field trials, the maximum expected residues
in barley bran would be 0.016 ppm, which is below the recommended 0.02
ppm tolerance for barley, grain.  Therefore, a separate tolerance is not
needed for barley, bran.  Based on the 1.6x processing factor for wheat
bran, and a HAFT residue of 0.109 ppm from the oat field trials, the
maximum expected residues in oat bran would be 0.17 ppm, which is above
the recommended 0.08 ppm tolerance for oat, grain.  Therefore, a
separate tolerance should be established for oat, bran at 0.20 ppm.
However, according to current HED guidelines, HED does not currently set
tolerances for residues on oat, bran.  The residue level was
incorporated into the dietary exposure assessment.  Based on the 1.6x
processing factor for wheat bran, and a HAFT residue of 0.011 ppm from
the wheat field trials, the maximum expected residues in rye bran would
be 0.018 ppm, which is below the recommended 0.02 ppm tolerance for rye,
grain.  Therefore, a separate tolerance is not needed for rye, bran.

Using the data from the adequate cattle feeding study and a calculated
MTDB of 0.39 ppm for pyrasulfotole and pyrasulfotole-desmethyl residues
in dairy cattle diets, estimated pyrasulfotole and
pyrasulfotole-desmethyl residues in ruminants at a 1X dose level are
0.16 ppm in liver, 0.029 ppm in kidney; and <LOQ in milk, meat and fat.
Based on the quantifiable residues and in order to harmonize with PMRA,
tolerances should be established for residues of pyrasulfotole and
pyrasulfotole-desmethyl on liver of cattle, goat, horse, and sheep at
0.35 ppm; and meat byproducts, except liver, of cattle, goat, horse, and
sheep at 0.06 ppm.  Although, there is no reasonable expectation of
finding quantifiable residues of pyrasulfotole and
pyrasulfotole-desmethyl in milk; milk, fat; and fat and muscle of
cattle, goat, horse and sheep, PMRA policy requires the establishment of
tolerances at the LOQ level for commodities in which there is no
expectation of finite residues.  Therefore, in order to harmonize with
PMRA, the following tolerances for residues of pyrasulfotole and
pyrasulfotole-desmethyl should be established:  0.01 ppm in milk; and
0.02 ppm in fat and meat of cattle, goat, horse and sheep.

Using data from the adequate cattle feeding study and a calculated MTDB
of 0.014 ppm pyrasulfotole and pyrasulfotole-desmethyl in hogs, the
estimated pyrasulfotole and pyrasulfotole-desmethyl residues in hogs
were 0.0000046 ppm in muscle, 0.0011 ppm in kidney, and 0.0059 ppm in
liver.  There is no reasonable expectation of finding quantifiable
residues of pyrasulfotole and pyrasulfotole-desmethyl in hog tissues.
However, in order to harmonize with PMRA, the following tolerances for
residues of pyrasulfotole and pyrasulfotole-desmethyl should be
established:  0.02 ppm in fat, meat, and meat byproducts of hogs.

For purposes of this petition, using the data from the poultry
metabolism studies and a calculated MTDB of 0.058 ppm for poultry, the
maximum estimated pyrasulfotole and pyrasulfotole-desmethyl residues in
poultry were 0.00025 ppm in muscle, 0.00043 ppm in fat, and 0.010 ppm in
liver.  As the total extractable residues in eggs were <0.01 ppm; the
samples were not analyzed further for identification purposes.  Based on
the results of the poultry metabolism study, there is no reasonable
expectation of finding quantifiable residues of pyrasulfotole and
pyrasulfotole-desmethyl in eggs and poultry tissues.  However, in order
to harmonize with PMRA, the following tolerances for residues of
pyrasulfotole and pyrasulfotole-desmethyl should be established:  0.02
ppm in fat, meat, and meat byproducts of poultry.

The results of the submitted confined and limited field rotational crop
studies together are adequate to determine appropriate plantback
intervals (PBIs) for rotational crops.  In the confined rotational crop
study, following application of either phenyl- or pyrazole-labeled
pyrasulfotole, the TRR in the 122-DAT Swiss chard, turnip tops, and
turnip roots were <0.01 (<LOQ).  In the limited field rotational crop
study, maximum residue levels of pyrasulfotole and
pyrasulfotole-desmethyl were <LOD in all corn and soybean RACs at PBIs
of 114-123 days.  Maximum residues levels for pyrasulfotole-benzoic acid
were 0.0018 ppm in corn forage, 0.0027 ppm in soybean forage, 0.0126 ppm
in soybean hay and <LOD in corn grain, corn stover and soybean seed.
However, it was determined that residues of pyrasulfotole-benzoic acid
are not of concern for both tolerance and risk assessment purposes.
Therefore, the submitted confined and limited field trial data support
the proposed PBIs.

The residue chemistry database supports the establishment of the
permanent tolerances for the combined residues of pyrasulfotole and
pyrasulfotole-desmethyl in/on the RACs listed in Appendix C.

5.1.11	International Residue Limits  TC "5.1.11	International Residue
Limits" \f C \l "3"

There are no established Mexican, Canadian or Codex MRLs for the
proposed uses.  As mentioned previously, pyrasulfotole is being
evaluated as part of a trilateral joint review with Canada and
Australia.  All HED-recommended tolerances are the same as those being
established in Canada and Australia.  Therefore, harmonization is not an
issue at this time.

5.2	Dietary Exposure and Risk  TC "5.2	Dietary Exposure and Risk" \f C
\l "2"

Pyrasulfotole acute and chronic dietary exposure assessments were
conducted using DEEM-FCID(, Version 1.30), which incorporates
consumption data from USDA’s CSFII, 1994-1996 and 1998.  The 1994-96,
98 data are based on the reported consumption of more than 20,000
individuals over two non-consecutive survey days.  Foods “as
consumed” (e.g., apple pie) are linked to EPA-defined food commodities
(e.g. apples, peeled fruit - cooked; fresh or N/S; baked; or wheat flour
- cooked; fresh or N/S, baked) using publicly available recipe
translation files developed jointly by USDA/ARS and EPA.  Consumption
data are averaged for the entire U.S. population and within population
subgroups for chronic exposure assessment, but are retained as
individual consumption events for acute exposure assessment.

For chronic exposure and risk assessment, an estimate of the residue
level in each food or food-form (e.g., orange or orange juice) on the
food commodity residue list is multiplied by the average daily
consumption estimate for that food/food form.  The resulting residue
consumption estimate for each food/food-form is summed with the residue
consumption estimates for all other food/food-forms on the commodity
residue list to arrive at the total average estimated exposure.
Exposure is expressed in mg/kg body weight/day and as a percent of the
cPAD.  This procedure is performed for each population subgroup.

For acute exposure assessments, individual one-day food consumption data
are used on an individual-by-individual basis.  The reported consumption
amounts of each food item can be multiplied by a residue point estimate
and summed to obtain a total daily pesticide exposure for a
deterministic exposure assessment, or “matched” in multiple random
pairings with residue values and then summed in a probabilistic
assessment.  The resulting distribution of exposures is expressed as a
percentage of the aPAD on both a user (i.e., those who reported eating
relevant commodities/food forms) and a per-capita (i.e., those who
reported eating the relevant commodities as well as those who did not)
basis.  In accordance with HED policy, per capita exposure and risk are
reported for all tiers of analysis.  However, for Tiers 1 and 2,
significant differences in user vs. per capita exposure and risk are
identified and noted in the risk assessment.

r below this level are not of concern.  The DEEM-FCID™ analysis
estimates the dietary exposure of the U.S. population and 26 population
subgroups.  The results reported in Table 5.2 are for the U.S.
Population, all infants (<1 year old), children 1-2, children 3-5,
children 6-12, youth 13-19, females 13-49, males 20-49, and adults 50+
years.

5.2.1	Acute Dietary Exposure/Ris  TC "5.2.1	Acute Dietary Exposure/Ris"
\f C \l "3"  k

An unrefined, acute dietary exposure assessment was performed for the
general U.S. population and all other population subgroups (including
infants and children) using tolerance-level residues and assuming 100%
CT for all proposed uses.  Drinking water was incorporated directly in
the dietary assessment using the acute concentration for surface water
generated by the FIRST model.  The results of this assessment indicate
that the acute dietary exposure estimates (95th percentile) are not of
concern to HED (<100% of the aPAD) for the general U.S. population (2%
of the aPAD) and all other populations subgroups.  The most highly
exposed population subgroup is children 1-2 years old at 4% of the aPAD.

5.2.2	Chronic Dietary Exposure/Risk  TC "5.2.2	Chronic Dietary
Exposure/Risk" \f C \l "3"

An unrefined, chronic dietary exposure assessment was performed for the
general U.S. population and various population subgroups using
tolerance-level residues and assuming 100% CT for all proposed uses.
Drinking water was incorporated directly into the dietary assessment
using the chronic concentration for surface water generated by the FIRST
model.  The results of the assessment conclude that the chronic dietary
exposure estimates are below HED’s level of concern (<100% of the
cPAD) for the general U.S. population (2% of the cPAD) and all
population subgroups.  The most highly exposed population subgroup is
children 1-2 years old at 7% of the cPAD.

Table 5.2.  Summary of Dietary Exposure and Risk for Pyrasulfotole.

Population

Subgroup	Acute Dietary1	Chronic Dietary2

	Dietary Exposure

(mg/kg/day)	% aPAD	Dietary Exposure

(mg/kg/day)	% cPAD

U.S. Population (total)	0.000633	2	0.000224	2

All Infants (< 1 year old)	0.001259	3	0.000410	4

Children 1-2 years old	0.001393	4	0.000698	7

Children 3-5 years old	0.001053	3	0.000541	5

Children 6-12 years old	0.000691	2	0.000339	3

Youth 13-19 years old	0.000431	1	0.000190	2

Adults 20-49 years old	0.000378	1	0.000168	2

Adults 50+ years old	0.000331	1	0.000160	2

Females 13-49 years old	0.000368	1	0.000161	2

1 Acute dietary endpoint of 0.038 mg/kg/day applies to the general U.S.
population and all population subgroups.

2 Chronic dietary endpoint of 0.01 mg/kg/day applies to the general U.S.
population and all population subgroups.

6.0	Residential (Non-Occupational) Exposure/Risk Characterization  TC
"6.0	Residential (Non-Occupational) Exposure/Risk Characterization" \f C
\l "1"

As there are currently no registered or proposed residential uses for
pyrasulfotole, a residential exposure assessment was not conducted.

6.1	Other (Spray Drift, etc.)  TC "6.1	Other (Spray Drift, etc.)" \f C
\l "2"

Spray drift is always a potential source of exposure to residents nearby
to spraying operations.  This is particularly the case with aerial
application, but, to a lesser extent, could also be a potential source
of exposure from the ground application method employed for
pyrasulfotole.  The Agency has been working with the Spray Drift Task
Force, EPA Regional Offices and State Lead Agencies for pesticide
regulation and other parties to develop the best spray drift management
practices.  On a chemical by chemical basis, the Agency is now requiring
interim mitigation measures for aerial applications that must be placed
on product labels/labeling.  The Agency has completed its evaluation of
the new database submitted by the Spray Drift Task Force, a membership
of U.S. pesticide registrants, and is developing a policy on how to
appropriately apply the data and the AgDRIFT® computer model to its
risk assessments for pesticides applied by air, orchard airblast and
ground hydraulic methods.  After the policy is in place, the Agency may
impose further refinements in spray drift management practices to reduce
off-target drift with specific products with significant risks
associated with drift.

7.0	Aggregate Risk Assessments and Risk Characterization  TC "7.0
Aggregate Risk Assessments and Risk Characterization" \f C \l "1"

In accordance with the FQPA, HED must consider and aggregate pesticide
exposures and risks from three major sources: food, drinking water, and
residential exposures.  In an aggregate assessment, exposures from
relevant sources are added together and compared to quantitative
estimates of hazard (e.g., a NOAEL or PAD), or the risks themselves can
be aggregated.  When aggregating exposures and risks from various
sources, HED considers both the route and duration of exposure.

For pyrasulfotole, aggregate exposure risk assessments were performed
for the following scenarios:  acute aggregate exposure (food and
drinking water), and chronic aggregate exposure (food and drinking
water).  Short- and intermediate-term assessments, which are used to
evaluate aggregate dietary and residential exposures, were not performed
because there are no registered or proposed residential non-food uses.
Because pyrasulfotole is classified as “Suggestive Evidence of
Carcinogenicity” and HED CARC recommended that a separate
quantification of cancer risk is not required.  Therefore, cancer
aggregate risk assessments were not performed.

7.1	Acute Aggregate Ris  TC "7.1	Acute Aggregate Ris" \f C \l "2"  k

The acute aggregate risk assessment takes into account exposure
estimates from dietary consumption of pyrasulfotole (food and drinking
water).  The acute dietary exposure estimates, are not of concern to HED
(<100% aPAD) at the 95th exposure percentile for the general U.S.
population and all other population subgroups (see Table 5.2).  The
dietary exposure assessment was a screening-level assessment, utilizing
tolerance-level residues and 100% CT information for all proposed
agricultural uses and a Tier 1 acute surface water EDWCs generated by
FIRST.  Therefore, the acute aggregate risk associated with the proposed
uses of pyrasulfotole is not of concern to HED for the general U.S.
population or any population subgroups.

7.2	Chronic Aggregate Risk  TC "7.2	Chronic Aggregate Risk" \f C \l "2"

The chronic aggregate risk assessment takes into account average
exposure estimates from dietary consumption of pyrasulfotole (food and
drinking water).  The chronic dietary exposure estimates are not of
concern to HED (<100% cPAD) for the general U.S. population and all
population subgroups (see Table 5.2).  The dietary exposure assessment
was a screening-level assessment, utilizing tolerance-level residues and
100% CT information for all proposed agricultural uses and a Tier 1
chronic surface water EDWCs generated by FIRST.  Therefore, the chronic
aggregate risk associated with the proposed uses of pyrasulfotole is not
of concern to HED for the general U.S. population or any population
subgroups.

8.0	Cumulative Risk Characterization/Assessment  TC "8.0	Cumulative Risk
Characterization/Assessment" \f C \l "1"

Pyrasulfotole, mesotrione, isoxaflutole and topramezone belongs to a
class of herbicides that inhibit the liver enzyme
4-hydroxyphenylpyruvate dioxygenase (HPPD), which is involved in the
catabolism (metabolic breakdown) of tyrosine (an amino acid derived from
proteins in the diet).  Inhibition of HPPD can result in elevated
tyrosine levels in the blood, a condition called tyrosinemia.
HPPD-inhibiting herbicides have been found to cause a number of
toxicities in laboratory animal studies including ocular, developmental,
liver and kidney effects.   Of these toxicities, it is the ocular effect
(corneal opacity) that is highly correlated with the elevated blood
tyrosine levels. In fact, rats dosed with tyrosine alone show ocular
opacities similar to those seen with HPPD inhibitors.  Although the
other toxicities may be associated with chemically-induced tyrosinemia,
other mechanisms may also be involved.

There are marked differences among species in the ocular toxicity
associated with inhibition of HPPD.  Ocular effects following treatment
with HPPD inhibitor herbicides are seen in the rat but not in the mouse.
 Monkeys also seem to be recalcitrant to the ocular toxicity induced by
HPPD inhibition.  The explanation of this species-specific response in
ocular opacity is related to the species differences in the clearance of
tyrosine.  A metabolic pathway exists to remove tyrosine from the blood
that involves a liver enzyme called tyrosine aminotransferase (TAT). In
contrast to rats where ocular toxicity is observed following exposure to
HPPD-inhibiting herbicides, mice and humans are unlikely to achieve the
levels of plasma tyrosine necessary to produce ocular opacities because
the activity of TAT in these species is much greater compared to rats.
Thus, humans and mice have a highly effective metabolic process for
handling excess tyrosine.

HPPD inhibitors (e.g., Nitisinone) are used as an effective therapeutic
agent to treat patients suffering from rare genetic diseases of tyrosine
catabolism.  Treatment starts in childhood but is often sustained
throughout patient’s lifetime.  The human experience indicates that a
therapeutic dose (1 mg/kg/day dose) of Nitisinone has an excellent
safety record in infants, children and adults and that serious adverse
health outcomes have not been observed in a population followed for
approximately a decade.   Rarely, ocular effects are seen in patients
with high plasma tyrosine levels; however these effects are transient
and can be readily reversed upon adherence to a restricted protein diet.
 This indicates that an HPPD inhibitor in it of itself cannot easily
overwhelm the tyrosine-clearance mechanism in humans.

Therefore, exposure to environmental residues of HPPD-inhibiting
herbicides are unlikely to result in the high blood levels of tyrosine
and ocular toxicity in humans due to an efficient metabolic process to
handle excess tyrosine.  In the future, assessments of HPPD-inhibiting
herbicides willl consider more appropriate models and cross species
extrapolation methods.

Therefore, EPA has not conducted cumulative risk assessment with other
HPPD inhibitors (HED Doc. D 341612; dated 7/02/07).

9.0	Occupational Exposure/Risk Pathway  TC "9.0	Occupational
Exposure/Risk Pathway" \f C \l "1"

An occupational exposure assessment was provided in a HED memorandum
dated 05/01/07 (K. Lowe; DP# 333434).  Based on the proposed use
patterns, occupational handler and post-application exposure to
pyrasulfotole is expected.  The labels for pyrasulfotole recommend that
the products be applied between the 1 leaf and up to flag leaf emergence
and only one application is allowed per season, therefore, most
exposures will be short-term (i.e., 1-30 days) in duration; and, only
short-term dermal and inhalation exposures were assessed.

9.1	Short-Term Handler Ris  TC "9.1	Short-Term Handler Ris" \f C \l "2"
k

The proposed use patterns indicate that the most highly-exposed
occupational pesticide handlers are likely to be mixer/loaders using
open-pour loading of liquids for aerial applications, and applicators
using aerial equipment.  As no chemical-specific data were available
with which to assess potential exposure of pyrasulfotole to pesticide
handlers, the estimates of exposure to pesticide handlers are based upon
surrogate study data available in the PHED Surrogate Exposure Guide
(August 1998).  For pesticide handlers, it is HED standard practice to
present estimates of dermal exposure for “baseline” that is, for
workers wearing a single layer of work clothing consisting of a
long-sleeved shirt, long pants, shoes plus socks and no protective
gloves, as well as for “baseline” and the use of protective gloves
or other PPE as might be necessary.  The proposed product labels
involved in this assessment direct applicators and other handlers to
wear a long-sleeved shirt and long pants, socks, shoes,
chemical-resistant gloves and protective eyewear.

Table 9.1 presents the exposure/risks for short and intermediate-term
dermal and inhalation exposures at baseline.  HED has no data to assess
exposures to pilots using open cockpits.  The only data available is
for exposure to pilots in enclosed cockpits.  Therefore, risks to
pilots are assessed using the engineering control (enclosed cockpits)
and baseline attire (long-sleeve shirt, long pants, shoes, and socks). A
MOE of 100 is adequate to protect occupational pesticide handlers.  All
MOEs are >100 with baseline attire; and, therefore, are not of concern
to HED.

Table 9.1.  Short-Term Occupational Exposure and Risk Estimates for use
of Pyrasulfotole on Small Cereal Grains.1

Exposure Scenario	Mitigation2	Daily

Dermal

Dose (mg/kg/day)3	Daily

Inhalation

Dose (mg/kg/day)3	Dermal

MOE4	Inhalation

MOE4	Combined MOE5

Mixer/Loader

Aerial Applications	Baseline	0.056	0.00093	180	1,100	150

Applicator

Aerial Equipment	Engineering control	0.000096	0.000052	100,000	19,000
16,000

1.  Short-term handler assessment was conducted assuming 1) the maximum
proposed application rate for cereal grains (0.045 lb ai/A); and 2) 1200
and 200 acres treated per day for mixer/loaders and applicators,
respectively (based on Exposure SAC SOP #9 “Standard Values for Daily
Acres Treated in Agriculture,” industry sources, and HED estimates).

2.  Baseline Dermal:  Long-sleeve shirt, long pants, and no gloves.
Baseline Inhalation: no respirator. Engineering control:  enclosed
cockpit and baseline attire (long-sleeve shirt, long pants, shoes, and
socks).

3.  Dose (mg/kg/day) = Unit exposure(mg/lb ai) x App Rate (lb ai/acre) x
Area Treated (acres/day) x  %Absorption (2.5% dermal and 100%
inhalation) / Body weight (70 kg).

4.  MOE = NOAEL/Dose; where the short-term dermal NOAEL = 10 mg/kg/day
and the short-term inhalation NOAEL = 1.0 mg/kg/day

5.  Combined MOE = NOAEL / (dermal + inhalation daily dose)

9.2	Short-Term Post-application Risk  TC "9.2	Short-Term
Post-application Risk" \f C \l "2"

Typically, there is the possibility for agricultural workers to
experience post-application exposures to dislodgeable pesticide
residues.  There are no chemical-specific data with which to estimate
post-application exposure of agricultural workers to dislodgeable
residues of pyrasulfotole.  Therefore, theoretical estimates of
exposure, based on surrogate studies, have been conducted.  The ExpoSAC
(SOP 003.1, Rev. 7 Aug. 2000, Regarding Agricultural Transfer
Coefficients; Amended ExpoSAC Meeting notes - 13 Sept 01) lists a number
of possible post-application agricultural activities relative the
proposed uses that might result in pesticide exposure to agricultural
workers.  TCs expressed as cm²/hr are identified for each of the
post-application, agricultural activities.  The TCs are derived from
data in surrogate exposure studies conducted during the various
activities listed.

The activities with the highest (i.e., most conservative) TCs related to
the proposed uses on small cereal grains were scouting and irritating.
For risk assessment purposes, the TCs are 100 cm²/hr and 1,500 cm²/hr
for scouting and irritating fields with plants of low and medium height,
respectively.  In addition to the above TCs, exposures during
post-application activities were estimated using the following
assumptions:

Application Rate	= 		0.045 lb ai/A

Exposure Duration	=	8 hours per day

Body Weight		=	70 kg

Dermal Absorption	= 	2.5%

Fraction of ai retained on foliage is assumed to be 20% (0.2) on day
zero (= % dislodgeable foliar residue, DFR, after initial treatment).
This fraction is assumed to further dissipate at the rate of 10% (0.1)
per day on following days.  These are default values established by
ExpoSAC.

Daily dermal doses were calculated on each post-application day after
application using the following equations:

Dermal Dose (mg/kg/day) = [DFR(t) (µg/cm2) x TC (cm2/hr) x ET (hr/day)
* CF1 * Abs (%)] / BW (kg)

Where:

	DFR(t)	=	Dislodgeable foliar residues at time “t” (0.1 µg/cm2 on
day 0);

	TC	=	Transfer Coefficient (cm2/hour);

ET	=	Exposure time meant to represent a typical workday (8 hours);

CF1	=	Conversion factor (0.001 mg/ug);

Abs	=	Dermal absorption (2.5%); and

BW	=	Body weight (70 kg).

and

DFR(t) (µg/cm2) =  [AR (lb ai/A) * (CF2/CF3)] * TR

Where:

	DFR(t)	=	Dislodgeable foliar residues at time “t” (0.1 µg/cm2 on
day 0);

	AR	=	Application rate (lb ai/A);

CF2	=	Conversion factor (4.54E+08 ug/lb)

CF1	=	Conversion factor (4.05E+07 cm2/A); and

TR	=	Transferable residue that can be dislodgeable foliar residue at
time (t) (20% on day 0).

Table 9.2 presents a summary of occupational short-term post-application
risks associated with the proposed uses of pyrasulfotole.  These
estimates are considered to be screening-level estimates (i.e.,
conservative and protective).  HED’s level of concern for dermal
exposure is for MOEs <100.  In this case, MOEs are greater than 100;
therefore, post-application dermal exposure is not of concern to HED for
agricultural workers.  Post-application inhalation exposure is expected
to be negligible.

Table 9.2.  Summary of Short-term Occupational Post-application Risks
for Pyrasulfotole on Small Cereal Grains.

Activities	TC (cm2/hr)1	Maximum Application Rate

(lb ai/acre)	MOE at Day 0	REI (days)

(Target MOE= 100)

Scouting, irrigation	100	0.045	350,000	12 hours

	1500

23,000	12 hours

1.  TC = transfer coefficient.

Pyrasulfotole is classified in Acute Toxicity Category III for acute
oral toxicity, acute dermal toxicity, and primary eye irritation.  It
classified in Category IV for acute inhalation toxicity and primary skin
irritation.  It is not a dermal sensitizer.  Therefore, the interim WPS
REI of 12 hours is adequate to protect agricultural workers from
post-application exposures.  The two proposed end-use product labels
list a REI of 12 hours.

10.0	Data Needs and Label Recommendations  TC "10.0	Data Needs and Label
Recommendations" \f C \l "1"

10.1	Toxicology  TC "10.1	Toxicology" \f C \l "2"

In vivo dermal penetration study.

10.2	Residue Chemistr  TC "10.2	Residue Chemistr" \f C \l "2"  y

Revised Section B to include instructions on rotation to all other crops
not currently listed.

Revised Section F to include the correct chemical name for
pyrasulfotole-desmethyl
[(5-hydroxy-1H-pyrazol-4-yl)[2-mesyl-4-(trifluoromethyl)phenyl]methanone
], and the HED-recommended tolerances and the correct commodity
definitions for small grain RACs and processed commodities.  In
addition, the proposed tolerance for triticale, grain deleted as it is
covered under the wheat, grain tolerance.

Submission of a new ruminant analytical enforcement method to determine
residues of pyrasulfotole and pyrasulfotole-desmethyl as well as
adequate radiovalidation and ILV data.

Submission of an analytical reference standard for pyrasulfotole,
pyrasulfotole-desmethyl and labeled internal standards to the EPA
National Pesticide Standards Repository.

For Method AI-001-P04-01, a separate confirmatory method will not be
required provided that two ion transitions are monitored during MS/MS
analysis for each analyte.  The petitioner can either revise the method
to include the information about the available second ion transition, or
submit a method addendum to include the second ion transition.

10.3	Occupational Exposure  TC "10.3	Occupational Exposure" \f C \l "2"

None.

Appendix A.	Toxicology Assessment  TC "Appendix A.	Toxicology
Assessment" \f C \l "1"

A.1.	Toxicology Data Requirements  TC "A.1.	Toxicology Data
Requirements" \f C \l "2"

The data requirements (40 CFR 158.340; 2005) for the proposed food uses
of pyrasulfotole technical are presented below.  Use of the guideline
numbers does not imply that the guideline protocols (1998) were used.

Test

	Technical

	Required	Satisfied

870.1100    Acute Oral Toxicity

870.1200    Acute Dermal Toxicity

870.1300    Acute Inhalation Toxicity

870.2400    Primary Eye Irritation

870.2500    Primary Dermal Irritation

870.2600    Dermal Sensitization		yes

yes

yes

yes

yes

yes	yes

yes

yes

yes

yes

yes

870.3100    Oral Subchronic (rodent)

870.3150    Oral Subchronic (nonrodent)

870.3200    21-Day Dermal

870.3250    90-Day Dermal

870.3465    90-Day Inhalation		yes

yes

yes

no

no	yes

yes

yes

-

-

870.3700a  Developmental Toxicity (rodent)

870.3700b  Developmental Toxicity (nonrodent)

870.3800    Reproduction		yes

yes

yes	yes

yes

yes

870.4100a  Chronic Toxicity (rodent)

870.4100b  Chronic Toxicity (nonrodent)

870.4200a  Oncogenicity (rat)

870.4200b  Oncogenicity (mouse)

870.4300    Chronic/Oncogenicity		yes

yes

yes

yes

yes	yes

yes

yes

yes

yes

870.5100    Mutagenicity—Gene Mutation - bacterial

870.5300    Mutagenicity—Gene Mutation - mammalian

870.5375    Mutagenicity—Structural Chromosomal Aberrations

870.5395    Mutagenicity—Other Genotoxic Effects		yes

yes

yes

yes	yes

yes

yes

yes

870.6100a  Acute Delayed Neurotox. (hen)

870.6100b  90-Day Neurotoxicity (hen)

870.6200a  Acute Neurotox. Screening Battery (rat)

870.6200b  90-Day Neuro. Screening Battery (rat)

870.6300    Develop. Neuro		no

no

yes

yes

yes	-

-

yes

yes

yes

870.7485    General Metabolism

870.7600    Dermal Penetration		yes

yes	yes

no

Special Studies for Ocular
Effects………………………………….	yes	yes

A.2.	Toxicity Profiles  TC "A.2.	Toxicity Profiles" \f C \l "2"

ACUTE TOXICITY PROFILE FOR PYRASULFOTOLE

Guideline No.	Study Type	MRID No.

	Results	Toxicity Category

870.1100

	Acute oral toxicity (rat)

Acceptable/Guideline	46801836

	LD50 > 2000 mg/kg (F)	III

870.1200

	Acute dermal toxicity (rat)

Acceptable/Guideline	46801837

	LD50 > 2000 mg/kg (M,F)	III

870.1300

	Acute inhalation toxicity (rat)

Acceptable/Guideline	46801838

	LC50 > 5.03 mg/L (M,F)	IV

870.2500

	Primary dermal irritation (rabbit)

Acceptable/Guideline	46801840

	Not a dermal irritant

	IV

870.2400

	Primary eye irritation (rabbit)

Acceptable/Guideline	46801839

	Moderate eye irritant

	III

870.2600

	Skin sensitization (guinea pig)

Acceptable/Guideline	46801841

	Not a dermal sensitizer	N/A

SUBCHRONIC AND CHRONIC TOXICITY AND GENOTOXICITY PROFILE FOR
PYRASULFOTOLE

Guideline No. 	Study Type	Results 	MRID No. (year)/ Classification
/Doses

N/A

	28-day oral toxicity (mouse; dietary)

	LOAEL = 961/1082 mg/kg/day [M/F], based on gritty content in the
urinary bladder and histopathology (urothelial hyperplasia, diffuse
submucosal granulation tissue, diffuse suburothelial mixed-cell
infiltrate) in the urinary bladder (males) and subcapsular hyperplasia
of the adrenal gland (females)

NOAEL = 192/233 mg/kg/day [M/F].	46801843 (2002)
Acceptable/Non-guideline

0, 200, 1000, or 5000 ppm (equal to 0/0, 35.8/45.0, 192/233, or 961/1082
mg/kg bw/day [M/F])

870.3100

	90-day oral toxicity (mouse; dietary)

	LOAEL not observed

NOAEL = 500/617 mg/kg/day (M/F).	46801844 (2003)

Acceptable/guideline

0, 100, 1500, or 3000 ppm (equal to 0/0, 16.5/19.7, 124/152, 259/326, or
500/617 mg/kg bw/day [M/F])

870.3200

	28-day dermal toxicity (rat)

	LOAEL = 100  mg/kg/day based on focal degeneration of the pancreas
(both sexes) and alteration of thyroid colloid (males)

NOAEL = 10 mg/kg/day.	46801904 (2005)

Acceptable/Guideline

0, 10, 100, or 1000 mg/kg bw/day

870.6200

	Subchronic neurotoxicity (rat; dietary)

	LOAEL = 42 mg/kg bw/day in females based on increased incidences of
corneal opacity and corneal neovascularization; not observed in males.
NOAEL was not observed in females; 345 mg/kg bw/day in males.	46801916
(2005)

Acceptable/Guideline

0, 500, 2500, or 5000 ppm (equivalent to 0/0, 32/42, 166/206, or 345/416
mg/kg bw/day [M/F])

870.6300

	Developmental neurotoxicity (rat; dietary)