UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, DC  20460

OFFICE OF PREVENTION,

PESTICIDES, AND TOXIC SUBSTANCES

MEMORANDUM

Date:		July 18, 2007

Subject:	Lambda-Cyhalothrin.  Human Health Risk Assessment for the
Proposed Food/Feed Uses of the Insecticide on Cucurbit Vegetables (Group
9), Tuberous and Corm Vegetables (Subgroup 1C), Grass Forage, Fodder,
and Hay (Group 17), Barley, Buckwheat, Oat, Rye, Wild Rice, and
Pistachios.  Petition Numbers 5F6994, 3E6593, and 6E7077.

			PC Code:			128897

			DP Numbers:			313315, 324219, 330542

			Regulatory Citation:		40CFR §180.438

			Chemical Class:		Synthetic Pyrethroid Insecticide

			Trade Names:		Warrior®, Karate®

From:		William T. Drew, Chemist and Risk Assessor

		Kim Harper, Toxicologist

		Anant Parmar, Dietary Exposure Assessor

		Registration Action Branch 2, Health Effects Division (7509P)

			and

		Mark Dow, Occupational/Residential Exposure Assessor

		Alternate Risk Integration Assessment Team

		Risk Integration Minor Use & Emergency Response Branch

		Registration Division (7505P)

Through:	Dennis McNeilly, Chemist

		Alan Levy, Toxicologist

		Margarita Collantes, Biologist

		Richard A. Loranger, Branch Senior Scientist

		Christina Swartz, Branch Chief

		Registration Action Branch 2, Health Effects Division (7509P)

To:		George LaRocca, Risk Manager

		Daniel Rosenblatt, Risk Manager

		Bonaventure Akinlosotu, Risk Manager Reviewer

		Insecticide Branch, Registration Division (7505P)

Table of Contents

  TOC \f  1.0	Executive Summary	4

2.0	Ingredient Profile	11

2.1	Summary of Registered/Proposed Uses	11

2.2	Structure and Nomenclature	  PAGEREF _Toc139000973 \h  13

2.3	Physical and Chemical Properties	  PAGEREF _Toc139000974 \h  13

3.0	Hazard Characterization/Assessment	14

3.1	Hazard and Dose-Response Characterization	14

3.1.1	Database Summary	14

<IP_ADDRESS>	Studies Available and Considered	14

<IP_ADDRESS>	Mode of Action, Metabolism, Toxicokinetic Data	14

3.1.2	Toxicological Effects	15

3.1.3	FQPA	15

3.2	Absorption, Distribution, Metabolism, Excretion (ADME)	16

3.3	FQPA Considerations	17

3.3.1	Adequacy of the Toxicity Database	17

3.3.2	Evidence of Neurotoxicity	17

3.3.3	Developmental Toxicity Studies	18

3.3.4	Reproductive Toxicity Study	18

3.3.5	Pre- and/or Post-Natal Toxicity	18

<IP_ADDRESS>	Determination of Susceptibility	18

<IP_ADDRESS>	Degree of Concern Analysis and Residual Uncertainties	19

3.3.6	Recommendation for a Developmental Neurotoxicity Study	19

3.3.7	Rationale for the UFDB	19

3.4	FQPA Safety Factor for Infants and Children	20

3.5	Hazard Identification and Toxicity Endpoint Selection	20

3.5.1	Acute Reference Dose (aRfD) - General Population	20

3.5.2	Chronic Reference Dose (cRfD) - General Population	21

3.5.3	Incidental Oral Exposure (Short- and Intermediate-Term)	21

3.5.4	Dermal Absorption	21

3.5.5	Dermal Exposure (All Durations)	21

3.5.6	Inhalation Exposure (All Durations)	23

3.5.7	Level of Concern for Margin of Exposure	24

3.5.8	Recommendation for Aggregate Exposure Risk Assessments	24

3.5.9	Classification of Carcinogenic Potential	24

3.5.10	Summary of Toxicological Doses and Endpoints	25

3.6	Endocrine disruption	27

4.0	Public Health and Pesticide Epidemiology Data	27

5.0	Dietary Exposure/Risk Characterization	  PAGEREF _Toc139001017 \h
27

5.1	Pesticide Metabolism and Environmental Degradation	  PAGEREF
_Toc139001018 \h  27

5.1.1	Metabolism in Primary Crops	  PAGEREF _Toc139001019 \h  27

5.1.2	Metabolism in Rotational Crops	  PAGEREF _Toc139001020 \h  27

5.1.3	Metabolism in Livestock	  PAGEREF _Toc139001021 \h  28

5.1.4	Analytical Methodology	  PAGEREF _Toc139001022 \h  28

5.1.5	Environmental Degradation	29

5.1.6	Comparative Metabolic Profile	30

5.1.7	Drinking Water Residue Profile	  PAGEREF _Toc139001027 \h  31

5.1.8	Food Residue Profile	32

5.1.9	International Residue Limits	33

5.2	Dietary Exposure and Risk	33

5.2.1  Acute Dietary Exposure/Risk	34

5.2.2  Chronic Dietary Exposure/Risk	35

5.2.3  Cancer Dietary Risk	35

5.3	Anticipated Residue and Percent Crop Treated (%CT) Information	36

6.0	Residential (Non-Occupational) Exposure/Risk Characterization	36

6.1	Handler	37

6.2	Post-Application	37

6.3	Spray Drift	38

7.0	Aggregate Risk Assessments and Risk Characterization	39

7.1	Acute Aggregate Risk	39

7.2	Short- and Intermediate-Term Aggregate Risk	39

7.3	Long-Term Aggregate Risk	39

7.4	Cancer Risk	40

8.0	Cumulative Risk Characterization/Assessment	40

9.0	Occupational Exposure/Risk Pathway	40

9.1	Short- and Intermediate-Term Handler Risk	40

9.2	Short- and Intermediate-Term Post-Application Risk	45

10.0	Data Needs and Label Requirements	47

10.1	Toxicology	47

10.2	Residue Chemistry	47

10.3	Occupational and Residential Exposure	47

References:	48

Appendix A:  Toxicology Assessment	49

A.1	Toxicology Data Requirements	49

A.2	Toxicity Profiles	50

A.3	Executive Summaries	54

	A.4
References……………………………………………………
…………………..67

Appendix B:  Metabolism Assessment	70

B.1	Metabolism Guidance and Considerations	70

Appendix C:  Human Research References	71

 1.0	Executive Summary

	Lambda-cyhalothrin is a synthetic pyrethroid insecticide used to
control a wide range of pests on food/feed crops and livestock, as well
as in and around buildings and structures.    SEQ CHAPTER \h \r 1
Lambda-cyhalothrin is an enriched isomer of cyhalothrin.  It is
currently used on a wide range of pests (including aphids, adult
Japanese beetles, grasshoppers, and butterfly larvae) in a variety of
applications.  It may also be used for structural pest management
(termiticide), and in public health applications to control insects
(such as mosquitoes, cockroaches, ticks, and flies) which may act as
disease vectors.  Another use is as a pour-on insecticide, which is
applied down the backline of beef cattle for control of lice and horn
flies.  There are existing residential uses for lambda-cyhalothrin.

	Syngenta Crop Protection (Syngenta) and Interregional Research Project
#4 (IR-4) have submitted petitions supporting new uses for
lambda-cyhalothrin as a microencapsulated formulation (capsule
suspension, CS) containing either 1.0 or 2.08 pounds of active
ingredient per gallon (lb ai/gal).  The   SEQ CHAPTER \h \r 1 proposed
new uses of lambda-cyhalothrin are on barley, buckwheat, oats, rye,
cucurbit vegetables, grasses, tuberous and corm vegetables, wild rice,
and pistachios.  The formulations being proposed for these uses include
a 1.0 lb ai/gal CS and a 2.08 lb ai/gal CS.  These formulations are
currently registered to Syngenta for use on a wide variety of food and
feed crops at seasonal rates of 0.06-0.48 lb ai per acre (lb ai/A).
Tolerances are established for the combined residues of
lambda-cyhalothrin and its epimer (R157836) in/on plant and animal
commodities under 40CFR §180.438.

Human Health Risk Assessment

Toxicology/Hazard

	The main target organ for lambda-cyhalothrin is the neuromuscular
system.  Lambda-cyhalothrin produces neurotoxicity in three species
(rats, mice, and dogs); neurotoxicity is evident in rats after oral,
dermal, and inhalation exposure.  As with other pyrethroids, inhalation
exposure appears to be the most toxic route of exposure.  The observed
neurotoxic effects are classic pyrethroid effects, and they are
toxicologically significant.  The observed liver effects in some studies
strongly suggest an adaptive response.  Lambda-cyhalothrin is classified
as “not likely to be carcinogenic to humans,” based on the lack of
evidence of carcinogenicity in mice and rats.  This classification was
determined at the HIARC meeting of 3/1/2004.

	Developmental studies in rats and rabbits exposed to cyhalothrin
demonstrated no indication of increased quantitative or qualitative
sensitivity of rats or rabbits to in utero exposure to cyhalothrin.  No
developmental toxicity was observed in either of the developmental
toxicity studies in rats and rabbits.  Maternal toxicity was observed in
the form of clinical signs of neurotoxicity in the rat study;
additionally, reduced body weight gain and food consumption were
observed in both the rat and the rabbit studies.

	A 3-generation reproduction study exposing rats to cyhalothrin
demonstrated no indication of increased quantitative or qualitative
sensitivity of rats to post-natal exposure to cyhalothrin.  In the
3-generation reproduction study in rats, the parental/offspring No
Observed Adverse Effect Levels (NOAELs) are the same, based on decreased
parental and pup body weight and body weight gain.

	The endpoint selected for assessment of acute dietary risk is
appropriate because it is based on effects that were observed within the
first 2 days of exposure in an oral study in dogs.  The NOAEL used for
the acute dietary dose is 0.5 mg/kg, with a Lowest Observed Adverse
Effect Level (LOAEL) of 3.5 mg/kg.  The endpoint selected for assessment
of chronic dietary risk is appropriate because it is based on a chronic
oral study in dogs.  This NOAEL (0.1 mg/kg/day) is somewhat lower than
those seen in dog studies with other pyrethroids; however, transient
effects were observed in several dogs at the LOAEL of 0.5 mg/kg/day.
SEQ CHAPTER \h \r 1 The short- and intermediate-term incidental oral
NOAELs are 0.1 mg/kg/day, based on clinical signs of neurotoxicity in
the chronic dog study at the LOAEL of 0.5 mg/kg/day.  The NOAEL for
dermal exposure is 10 mg/kg/day from a dermal toxicity study in rats,
and is based on clinical signs of neurotoxicity at the LOAEL of 50
mg/kg/day.  The NOAEL for inhalation exposure is 0.08 mg/kg/day in an
inhalation study in rats, and is based on clinical signs of
neurotoxicity at the LOAEL of 0.90 mg/kg/day.

	No additional uncertainty factors (UFs) have been retained, so HED’s
level of concern (LOC) is a margin of exposure (MOE) of less than 100.

FQPA Safety Factor

 The toxicology database is considered complete for the purposes of an
FQPA risk assessment.  Based on the developmental studies in rats and
rabbits, and the 3-generation and neurodevelopmental studies in rats,
there is no evidence of increased susceptibility.  The neurotoxicity
observed in adult animal studies raised a concern for potential
neurodevelopmental effects.  A rat neurodevelopmental toxicity (DNT)
study is available.   In this study, the lowest dose showing
neurotoxicity in the offspring (effects on mortality, body weights, body
weight gains, learning, learning and memory, and brain morphometry) is
10 mg/kg bw/day, with a NOAEL of 4 mg/kg bw/day.  Effects in offspring
and adult animals are found at a similar dose based on body weight
decreases.    It should be noted that some of the parameters evaluated
in this DNT study were regarded as acceptable but several others were
not, leading to a study classification of "unacceptable.” The study
deficiencies which, taken together, led to the unacceptable
classification include:  1) statistical analyses that adjusted for body
weights after treatment had begun, 2) an inadequate assessment of motor
activity, 3) an inadequate assessment of auditory startle in PND 61
females, and 4) missing low- and mid-dose morphometry data.

However, it is not likely that these limitations will impact the risk
assessment for the following reasons.  The slight changes in brain
morphometry were seen at the highest dose tested. Because these changes
were slight, it is uncertain whether toxicologically significant
differences would be seen at the mid dose, and it is unlikely that
significant changes would be seen at the lowest dose tested. The
auditory startle response is considered adequate for assessment in PND
23 males/females and PND 61 males where no treatment-related effects
were seen in auditory startle response.  Only the auditory response data
for PND 61 females is inadequate. Motor activity was examined and there
did not appear to be any differences between treated and control animals
other than decreases for multiple subsessions in PND 18 males/females at
the high dose only, but due to the high variability and the lack of
habituation, these data are considered equivocal.  If a 10-fold factor
is applied to the NOAEL in the study (i.e., 4 mg/kg bw/day) to account
for the scientific limitations of the study, the resulting value is 0.4
mg/kg bw/day.  The estimate of 0.4 mg/kg/day is similar to the doses
from the chronic dog study used for risk assessment (i.e., 0.5 mg/kg/day
for acute dietary exposure scenarios and 0.1 mg/kg/day for chronic
dietary exposure scenarios).  In the exposure databases, there are also
no residual uncertainties.  The exposure assessments are based on
reliable data and reasonable worst-case assumptions, and will not likely
underestimate risks.  There was no published literature found that would
indicate a neurodevelopmental concern for lambda-cyhalothrin.

Based on all of the considerations above, there is not a need to retain
the additional 10X safety factor for children. Application of the 10X
intraspecies uncertainty factor (which accounts for the possibility that
a subpopulation may be 10 times more sensitive than the average
individual) and a 10X interspecies factor (which accounts for the
possibility that humans may be 10 times more sensitive than animals) to
the dog NOAEL (i.e., the most sensitive species) should assure
protection of human health including children.

Dietary Exposure (Food/Water)

	The nature of the residue in plants is sufficiently understood.  The
residues to be regulated are lambda-cyhalothrin and its epimer R157836.

	An adequate confined rotational crop study is available indicating that
significant residues (greater than 0.01 ppm) will not be present in
crops rotated 30 days after application of lambda-cyhalothrin (EFED
review; 4/6/1988).

	Studies of lambda-cyhalothrin metabolism in ruminants and poultry have
been reviewed.  As with plants, HED has determined that the residues to
be regulated are lambda-cyhalothrin and its epimer R157836.  The other
minor animal metabolites do not need to appear in the tolerance
expression.

	Adequate gas chromatographic/electron capture detection (GC/ECD)
methods are available for enforcing tolerances on both plant (Method
PRAM 81) and animal (Method PRAM 86) commodities.  For both methods,
residues are extracted with   SEQ CHAPTER \h \r 1 acetone/hexane (1:1,
v/v), then cleaned up using liquid-liquid chromatography and Florisil
column chromatography.  Residues are determined by GC/ECD; the method
limit of quantitation (LOQ) is 0.01 ppm for each analyte.

	The available field trial data on potatoes, cucumbers, muskmelons,
summer squash, and grasses are adequate, and support the proposed use
patterns for lambda-cyhalothrin (CS) on tuberous and corm vegetables,
cucurbit vegetables, and grasses.  The number and geographic
distribution of the field trials are adequate, and the appropriate
samples were collected at the proposed pre-harvest intervals (PHIs).  In
addition to the new field trial data, adequate field trial data are
available on rice, wheat, almonds, and pecans from previously reviewed
petitions.  The data on rice will be translated to support an identical
use on wild rice; the data on almonds and pecans will be translated to
support an identical use on pistachios; and the data on wheat will be
translated to support identical uses on barley, buckwheat, oats, and
rye.

	Adequate storage stability data are available indicating that both
lambda-cyhalothrin and R157836 are stable under frozen storage in a wide
variety of raw and processed commodities for intervals of 26-36 months.
These data support the storage durations (2.9-8.5 months) and conditions
for samples from the field trials and processing studies submitted with
the current petitions.

	Adequate processing studies are available for potato and wheat grain;
processing data are not required for cucurbit vegetables, grass, nor
wild rice.  Separate tolerances are not required for potato processed
fractions.  However, based on the available wheat grain processing data,
separate tolerances are required for both barley and rye bran.

	The Codex Alimentarius Commission, Mexico, and Canada have all
established maximum residue limits (MRLs) for residues of
lambda-cyhalothrin in/on a variety of raw agricultural commodities.
Each of these regulatory bodies expresses residues in terms of only
cyhalothrin; however, the US tolerance expression includes both
lambda-cyhalothrin and its epimer R157836. For the crop uses currently
under consideration, only potatoes have existing international
tolerances, and the recommended US tolerance of 0.02 ppm will be in
harmony with the existing 0.02 mg/kg MRLs for Codex and Mexico.

he Dietary Exposure Evaluation Model (DEEM-FCID™, Version 2.03).  The
drinking water residues used in the dietary risk assessment were
provided by the Environmental Fate and Effects Division (EFED), and
incorporated directly into the dietary assessment.

	Acute Dietary Exposure Results and Characterization

	A refined acute probabilistic dietary exposure assessment was performed
for lambda-cyhalothrin to support all existing and proposed food uses,
and included drinking water exposure.  The acute dietary exposure
assessment incorporated processing factors and percent crop treated
(%CT) estimates provided by the Biological and Economic Analysis
Division (BEAD).  Acute anticipated residues were derived from PDP
monitoring data, field trial studies, and a market basket survey for
beef-fat.

	The acute drinking water concentration in surface water of 5.35 ppb was
based on the FIRST (FQPA Index Reservoir Screening Tool) estimated peak
concentration resulting from applications to orchards.

	The acute dietary exposure estimates for food and drinking water are
below HED’s LOC, 100% of the acute population adjusted dose (aPAD) for
the general US population and all population subgroups.
Lambda-cyhalothrin acute dietary exposure at the 99.9th percentile for
food and drinking water is 46% of the aPAD for the general US
population, and 61% of the aPAD for all infants (<1 year old), the most
highly-exposed population subgroup.

	Chronic Dietary Exposure Results and Characterization

	A refined chronic dietary exposure assessment was also conducted for
lambda-cyhalothrin to support all existing and proposed food uses, and
included drinking water exposure, utilizing point estimates of
anticipated residues for food and drinking water.  The chronic dietary
exposure assessment incorporated processing factors and %CT estimates
provided by BEAD.  Chronic anticipated residues were derived from PDP
monitoring data, field trial studies, and a market basket survey for
beef-fat.

	The chronic drinking water concentration in surface water of 0.130 ppb
was based on the FIRST estimated mean concentration resulting from
applications to orchards.

	The chronic dietary exposure estimates for food and drinking water are
below HED’s LOC, 100% of the chronic population adjusted dose (cPAD),
for the general US population and all population subgroups.
Lambda-cyhalothrin chronic dietary exposure for food and drinking water
is 17% of the cPAD for the general US population, and 50% of the cPAD
for children (1-2 yrs old), the most highly-exposed population subgroup.

Residential Exposure/Risks

	The residential risk assessment evaluated existing uses for
lambda-cyhalothrin.  Existing uses on turf, in gardens, on golf courses,
and for structural pest control were qualitatively assessed, but a
quantitative calculation was only completed for post-application
exposure on treated turf because this scenario is expected to have the
highest associated exposures.  This would be protective for all
residential exposures, even the handler scenarios, because the
anticipated dose levels for children playing on treated lawns exceed
those expected for all other scenarios.

	For post-application exposure, all residential MOES were well above the
Agency target MOE of 100 for the inhalation, dermal, and oral routes
(ranging from 700 to 15,000), and therefore do not exceed HED’s LOC.
Additionally, when the MOEs for the three routes were aggregated, MOEs
were still not of concern (MOEs for children were 460 to 500, and the
MOE for adults was 3000).

Aggregate Exposure/Risks

	Aggregate risk assessments (including both dietary and residential
exposure routes) for short- and intermediate-term durations were
conducted.  For these exposure durations, aggregate MOEs were greater
than the Agency target MOE of 100 (ranging from 140 to 490), and there
are thus no concerns for aggregate exposure.  For the acute and chronic
durations, the aggregate exposure and risk estimates are equivalent to
the dietary estimates, and are also not of concern.

Occupational Exposure/Risks

	Handlers

	An MOE of 100 or more is adequate to protect occupational pesticide
handlers from exposures to lambda-cyhalothrin.   Provided mixer/loaders
wear personal protective equipment (PPE) as directed by the labels, all
MOEs are greater than 100 (ranging from 110 to 1700), except for
mixer/loaders supporting aerial applications to wild rice at a rate of
0.04 lb ai per acre (lb ai/A), and 1200 acres treated per day (A/day).
Their exposure can be mitigated by reducing the amount of ai handled per
day, or by the use of a dust-mist respirator.  Baseline MOEs for
applicators and flaggers range from 820 to 4900.

	Post-application

	An MOE of 100 or more is adequate to protect persons from
post-application exposures to lambda-cyhalothrin, as described in the
proposed use patterns.  Because the estimated MOEs are all greater than
100 (ranging from 520 to 13,000), post-application exposures arising
from the proposed uses do not exceed HED’s LOC.

Environmental Justice Considerations

	Potential areas of environmental justice concerns, to the extent
possible, were considered for this human health risk assessment, in
accordance with US 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 USDA under the 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.
Whenever appropriate, non-dietary exposures based on home use of
pesticide products, 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 studies in which adult
human subjects were intentionally exposed to a pesticide or other
chemical.  These studies (listed in Appendix C) have been determined to
require a review of their ethical conduct, and they have received that
review.

Additional Data Needs

	Toxicology

Although several parameters were unacceptable in this study, as
explained in Sections 3.1.3 and 3.3.2, a repeat of this study is
unlikely to yield a lower regulatory endpoint. Thus, the database is
complete for purposes of this risk assessment. There are no data gaps
that would quantitatively impact the risk assessment.

   TC \l3 "3.3.7	Recommendation for a Developmental Neurotoxicity Study

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

	No major deficiencies were noted in the subject petitions that would
preclude the establishment of permanent tolerances for
lambda-cyhalothrin on the proposed commodities.  Only minor deficiencies
were noted pertaining to the proposed label directions and recommended
tolerance levels (listed below).  HED  SEQ CHAPTER \h \r 1  recommends
in favor of establishing permanent tolerances for lambda-cyhalothrin
residues at the levels listed in Table 1.0, below.

	(1) Use directions for grasses should be clarified to specify that the
restriction of 0.03 lb ai/A per cutting includes pastures and rangeland
in addition to grasses grown for seed.  A minimum RTI of 30 days should
be specified for pastures and rangeland which are not cut between
applications.  In addition, the PHI for forage should be changed to 0
days, as PHIs for forage are not practical for rangeland applications.

	(2) A tolerance was not proposed in rye bran.  Based on the available
wheat residue data, a separate tolerance is required at 0.2 ppm in rye,
bran.

	(3) Based on the calculated theoretical dietary burdens (TDBs) for
livestock, and the available livestock residue studies, the current
tolerance for lambda-cyhalothrin in milk fat is too low.  An increased
tolerance should be proposed in milk fat (10 ppm).  The data also
indicate that the current tolerances in hog commodities could be lowered
to 0.2 ppm in fat, 0.01 ppm in meat, and 0.02 ppm in meat-byproducts.

	Regulatory Recommendations and Occupational and Residential Exposure
TC \l2 "10.3	Occupational and Residential Exposure

	The labels for Warrior® Insecticide (EPA Registration #100-1112) and
Karate® Insecticide (EPA Registration #100-1097) should state that
mixer/loaders supporting aerial applications to wild rice at a rate of
0.04 lb ai/A, and treating 1200 acres (or more) per day, are required to
use a dust-mist respirator.

Table 1. 0	Tolerance Summary for Lambda-Cyhalothrin.

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

Barley, bran	0.2	0.2	Tolerances are based on the existing residue data
and tolerances in similar wheat commodities.

Barley, grain	0.05	0.05

	Barley, hay	2.0	2.0

	Barley, straw	2.0	2.0

	Buckwheat, grain	0.05	0.05

	Cucurbit vegetables	0.05	0.05	Vegetable, cucurbits, group 9

Grass forage, fodder, and hay	9.0	7.0	A crop group tolerance is
appropriate.

Grass forage, fodder, and hay, group 17

Hog, fat	3.0	0.2	Based on a TDB* of 0.9 ppm for swine, the maximum
expected residues are 0.16 ppm in hog fat, 0.006 ppm in hog meat, and
0.011 ppm in hog meat-byproducts.

Hog, meat	0.2	0.01

	Hog, meat-byproducts	0.2	0.02

	Milk, fat (reflecting 0.4 ppm in whole milk)	5.0	10	Based on a TDB of
10.4 ppm for dairy cattle, the maximum expected residues in milk are
0.35 ppm, equivalent to 8.8 ppm in milk fat.

Oat, grain	0.05	0.05	Tolerances are based on the existing residue data
and tolerances in similar wheat commodities.

Oat, forage	2.0	2.0

	Oat, hay	2.0	2.0

	Oat, straw	2.0	2.0

	Pistachio	0.05	0.05	Tolerance is based on existing almond and pecan
residue data, and the tolerance in the tree nut group.

Rice, wild, grain	1.0	1.0	Tolerance is based on the existing tolerance
and residue data in rice.

Rye, bran	None	0.2	Tolerances are based on the existing residue data and
tolerances in similar wheat commodities.

Rye, grain	0.05	0.05

	Rye, forage	2.0	2.0

	Rye, straw	2.0	2.0

	Tuberous and corm vegetables	0.05	0.02	Combined residues were <0.02 ppm
in/on all potato samples from all field trials conducted at 1x rate, and
from the field trial conducted at a 5x rate.

Vegetable, tuberous and corm, subgroup 1C

* TDB = Theoretical Dietary Burden.

  TC \l1 "1.0	Ex

ecutive Summary 2.0	Ingredient Profile

	Lambda-cyhalothrin is a synthetic pyrethroid insecticide used to
control a wide range of pests on food/feed crops and livestock, as well
as in and around buildings and structures.    SEQ CHAPTER \h \r 1
Lambda-cyhalothrin is an enriched isomer of cyhalothrin, and is
classified as a Type II pyrethroid compound.

	Syngenta Crop Protection has submitted a petition (PP#5F6994) proposing
the use of 1.0 and 2.08 lb ai/gal CS formulations of lambda-cyhalothrin
on tuberous and corm vegetables (subgroup 1C), cucurbit vegetables
(group 9), and grasses (group 17).  In addition, IR-4 submitted two
petitions (PPs#3E6593 and 6E7077) proposing to expand the use of
lambda-cyhalothrin (CS) to include barley, buckwheat, oats, rye, wild
rice, and pistachios, based on the existing residue data and tolerances
on wheat, rice, and tree nuts.

2.1	Summary of Registered/Proposed Uses

	Table 2.1, below, summarizes the proposed use patterns and formulations
specified for the two end-use products containing lambda-cyhalothrin.

Table 2.1	Summary of Directions for Use of Lambda-Cyhalothrin.

Application Timing, Type, and Equipment	Formulation

[EPA Reg. #]	Use Rate

(lb ai/A)	Max. # Applic. per Season	Max. Seasonal Use Rate

(lb ai/A)	PHI

(Days)	Use Directions and Limitations

Cereal Grains (including Wheat, Wheat Hay, Triticale, Barley, Buckwheat,
Oats, and Rye)

Broadcast foliar applications using ground or aerial equipment	1.0 lb
ai/gal CS

[100-1112]

2.08 lb ai/gal CS

[100-1097]	0.03	2	0.06	7

[forage, hay]

30

[grain, straw]	The minimum RTI is 3 days.

Do not allow livestock to graze within 7 days of treatment.  Use a
minimum of 2 and 10 gal/A for aerial and ground applications,
respectively.

Cucurbit Vegetables

Broadcast foliar applications using ground or aerial equipment	1.0 lb
ai/gal CS

[100-1112]	0.03	6	0.18	1	The minimum RTI is 5 days.  Use a minimum of 2
and 10 gal/A for aerial and ground applications, respectively.

Grass Forage, Fodder and Hay

Broadcast foliar applications using ground or aerial equipment	1.0 lb
ai/gal CS

[100-1112]

2.08 lb ai/gal CS

[100-1097]	0.03	3	0.09	1

[forage]

7

[hay, straw, and seed screenings]	Do not apply more than 0.03 lb ai/A
per cutting.  Following application to grasses grown for seed, regrowth
may be cut for forage or hay 30 days after harvest of seed.  Use a
minimum of 2 and 7 gal/A for aerial and ground applications,
respectively.

Tuberous and Corm Vegetables

Broadcast foliar applications using ground or aerial equipment	1.0 lb
ai/gal CS

[100-1112]	0.03	4	0.12	7	The minimum RTI is 7 days.

Use a minimum of 2 and 10 gal/A for aerial and ground applications,
respectively.

Rice and Wild Rice

Broadcast foliar applications using ground or aerial equipment	1.0 lb
ai/gal CS

[100-1112]

2.08 lb ai/gal CS

[100-1097]	0.04	3	0.12	21	Do not apply more than 0.08 lb ai/A within 28
days of harvest, or more than 0.04 lb ai/A within 21 days of harvest.
The minimum RTI is 5 days.  Do not release flood water within 7 days of
application.  Do not use treated rice fields for the aquaculture of
edible fish and crustacaea.  Do not apply as an ULV spray.  Use a
minimum of 2 gal/A for aerial applications.

Tree Nuts (including Pistachio)

Broadcast foliar applications during growing season using ground or
aerial equipment	1.0 lb ai/gal CS

[100-1112]	0.04	4	0.16	14	Do not apply more than 0.12 lb ai/A/year
post-bloom.  The minimum RTI is 5 days.  Use a minimum of 5 gal/A for
aerial applications.

2.2	Structure and Nomenclature  TC \l2 "2.2	Structure and Nomenclature

Table 2.2	Lambda-Cyhalothrin Nomenclature.

Compound

	1:1 mixture of (Z)-(1R,3R), S-ester: (Z)-(1S,3S), R-ester

)-α-cyano-3-phenoxybenzyl
(1S)-cis-3-[(Z)-2-chloro-3,3,3-trifluoropropenyl]-2,2-dimethylcyclopropa
necarboxylate and (S)-α-cyano-3-phenoxybenzyl
(1R)-cis-3-[(Z)-2-chloro-3,3,3-trifluoropropenyl]-2,2-dimethylcyclopropa
necarboxylate

CAS Name	rel-(R)-cyano(3-phenoxyphenyl)methyl
(1S,3S)-3-[(1Z)-2-chloro-3,3,3-trifluoro-1-propenyl]-2,2-dimethylcyclopr
opanecarboxylate

CAS Registry Number	91465-08-6

End-use Products (EPs)	1.0 lb ai/gal CS (Warrior® Insecticide with
Zeon™ Technology; EPA Registration #100-1112)

2.08 lb ai/gal CS (Karate® Insecticide with Zeon™ Technology; EPA
Registration #100-1097)

2.3	Physical and Chemical Properties  TC \l2 "2.3	Physical and Chemical
Properties

Table 2.3	Physicochemical Properties of Lambda-Cyhalothrin.

Parameter	Value	Reference

Melting Point/Range (°C)	49.2	D284860 1

pH	NA 2

	Density (g/cm3 at 25°C)	1.33

	Water Solubility (mg/L at 20ºC, pH 6.5)	0.005

	Solvent Solubility (g/L)	NA

	Vapor Pressure (mm Hg at 20°C)	1.5 x 10-9

	Dissociation Constant (pKa at 20°C)	>9

	Octanol/water Partition Coefficient (Log[KOW])	7.00

	UV/visible Absorption Spectrum	NA

	1. Kit Farwell, 8/15/2002.

2. NA = Not Available.

3.0	Hazard Characterization/Assessment  TC \l1 "3.0	Hazard
Characterization/Assessment

	Lambda-cyhalothrin is moderately acutely toxic via the oral, dermal,
and inhalation routes (Category II).  It is also a moderate eye irritant
(Category II).  It is neither irritating to the skin nor is it a
sensitizer in the guinea pig.  Acute toxicity studies conducted with
cyhalothrin indicate that it is also Category II via the oral, dermal
(rat), and inhalation routes.  It is a moderate eye irritant without
irrigation, and a mild eye irritant with irrigation (Category III).  It
is a mild skin irritant in rats, but not an irritant in rabbits
(Category IV).  Cyhalothrin is a skin sensitizer in guinea pigs.

3.1	Hazard and Dose-Response Characterization  TC \l2 "3.1	Hazard and
Dose-Response Characterization

	The toxicological database for lambda-cyhalothrin, when bridged with
that for cyhalothrin, indicates one major target for this chemical: the
neuromuscular system.  The neuromuscular effects are typical of
chemicals in the pyrethroid class of insecticides.  The neuromuscular
effects are consistently characterized by gait abnormalities and
salivation; these effects are observed across species, and across routes
of administration (oral, dermal, and inhalation).  A comparison of the
90-day oral study in rats with the chronic feeding study in rats
indicates that toxicity is not induced at lower dose levels when rats
are exposed over a longer period of time.  As with other pyrethroids,
the dog appears to be the most sensitive species, exhibiting gait
abnormalities at doses as low as 0.5 mg/kg/day, starting at week 2.
Neither sex appears to be more sensitive.  In studies where the liver is
affected, it appears to be an adaptive response.

3.1.1	Database Summary  TC \l3 "3.1.1	Database Summary

<IP_ADDRESS>	Studies Available and Considered   TC \l4 "<IP_ADDRESS>	Studies
available and considered (animal, human, general literature)

	Through the use of bridging data, the toxicology database for
lambda-cyhalothrin has been completed using developmental, reproduction,
chronic (rodent), and oncogenicity studies conducted with cyhalothrin.
The toxicology database for lambda-cyhalothrin, when bridged with
cyhalothrin, is complete for the purposes of this risk assessment; there
are no data gaps that would quantitatively impact the risk assessment.
The scientific quality is relatively high, and the toxicity profile of
lambda-cyhalothrin can be characterized for all effects, including
potential developmental, reproductive, and neurotoxic effects.  The data
provided no indication of increased susceptibility of rats or rabbits to
in utero and/or post-natal exposure to cyhalothrin.

<IP_ADDRESS>	Mode of Action, Metabolism, Toxicokinetic Data  TC \l4 "<IP_ADDRESS>
Mode of action, metabolism, toxicokinetic data

	G.W. Ware (The Pesticide Book; 4th Edition; 1994; pages 62-64, 171-172)
states that, “Pyrethroids initially stimulate nerve cells to produce
repetitive discharges, and eventually cause paralysis in the insect.
Such effects are caused by their action on the sodium channel, a tiny
hole through which sodium ions are permitted to enter the axon to cause
excitation.  These effects are produced in insect nerve cord, which
contains ganglia and synapses, as well as in giant nerve fiber axons.
The stimulating effect of pyrethroids is much more pronounced than that
of DDT.  The exact sites of action of pyrethroids at synapses are not
known.  It is probable that the toxic action of pyrethroids is primarily
due to its blocking action on the nerve axon since this action shows a
negative temperature coefficient.  But because the cockroach ganglion is
affected by pyrethroid concentrations many fold less than are required
to block conduction in giant fibers, it also seems likely that
pyrethroids act on some aspect of synaptic function.  The fast knockdown
of flying insects could be the result of rapid muscular paralysis,
suggesting that the ganglia of the insect central nervous system are
affected.”  Pyrethroid neurotoxicity in mammalian species is also
believed to be related to their effects on the sodium conductance
channel.

3.1.2	Toxicological Effects  TC \l3 "3.1.2	Toxicological Effects

	The main target organ for lambda-cyhalothrin is the neuromuscular
system.  Lambda-cyhalothrin produces neurotoxicity in three species
(rats, mice, and dogs); neurotoxicity is evident in rats after oral,
dermal, and inhalation exposure.  As with other pyrethroids, inhalation
exposure appears to be the most toxic route of exposure.  The observed
neurotoxic effects are classic pyrethroid effects, and they are
toxicologically significant.  The observed liver effects in some studies
appear to be an adaptive response.

	In an acute neurotoxicity study in the rats exposed to (-cyhalothrin,
clinical signs of neurotoxicity and changes in the FOB parameters were
observed; however, no treatment-related neuropathology was evident.
Clinical signs of neurotoxicity were observed in the chronic and
subchronic dog study (gait abnormalities, muscle tremors and
convulsions, subdued behavior, head shaking, excessive salivation);
developmental rat study (gait abnormalities); subchronic mouse study
(gait abnormalities, hunched posture); 21-day dermal rat study (reduced
splay reflex, gait abnormalities, reduced stability); 21-day inhalation
rat study (gait abnormalities, salivation, paw flicking, tail erections,
lachrymation, reduced foot withdrawal, reduced righting reflex, shaking,
head flicking, reduced splay reflex, decreased visual placing response);
and 28-day rat feeding study (gait abnormalities, hunched posture, tail
erect, salivation) studies.

	Developmental studies in rats and rabbits exposed to cyhalothrin were
available for consideration.  The data demonstrate no indication of
increased quantitative or qualitative sensitivity of rats or rabbits to
in utero exposure to cyhalothrin.  No developmental toxicity was
observed in either of the developmental toxicity studies in rats and
rabbits.  Maternal toxicity was observed in the form of clinical signs
of neurotoxicity in the rat study; additionally, reduced body weight
gain and food consumption were observed in both the rat and the rabbit
studies.

	A 3-generation reproduction study exposing rats to cyhalothrin is part
of the toxicology database.  The data demonstrate no indication of
increased quantitative or qualitative sensitivity of rats to post-natal
exposure to cyhalothrin.  In the 3-generation reproduction study in
rats, the parental/offspring NOAELs are the same, based on decreased
parental and pup body weight and body weight gain.

	The requirements for oncogenicity studies in the rat and the mouse with
lambda-cyhalothrin have been satisfied by a combined
chronic/oncogenicity study in rats, and an oncogenicity study in mice,
both conducted with cyhalothrin.  Although mice should have been tested
at a higher dose, it was determined that there was not enough
toxicological concern to warrant a requirement for a new carcinogenicity
study in mice.  The chemical is classified as “not likely to be
carcinogenic to humans,” based on the lack of evidence of
carcinogenicity in mice and rats.

FQPA

            The toxicology database is considered complete for the
purposes of an FQPA risk assessment.  Based on the developmental studies
in rats and rabbits, and the 3-generation and neurodevelopmental studies
in rats, there is no evidence of increased susceptibility.  The
neurotoxicity observed in adult animal studies raised a concern for
potential neurodevelopmental effects.  A rat neurodevelopmental toxicity
(DNT) study is available.   In this study, the lowest dose showing
neurotoxicity in the offspring (effects on mortality, body weights, body
weight gains, learning, learning and memory, and brain morphometry) is
10 mg/kg bw/day, with a NOAEL of 4 mg/kg bw/day.  Effects in offspring
and adult animals are found at a similar dose based on body weight
decreases.    It should be noted that some of the parameters evaluated
in this DNT study were regarded as acceptable but several others were
not, leading to a study classification of "unacceptable.” The study
deficiencies which, taken together, led to the unacceptable
classification include:  1) statistical analyses that adjusted for body
weights after treatment had begun, 2) an inadequate assessment of motor
activity, 3) an inadequate assessment of auditory startle in PND 61
females, and 4) missing low- and mid-dose morphometry data.

However, it is not likely that these limitations will impact the risk
assessment for the following reasons.  The slight changes in brain
morphometry were seen at the highest dose tested. Because these changes
were slight, it is uncertain whether toxicologically significant
differences would be seen at the mid dose, and it is unlikely that
significant changes would be seen at the lowest dose tested. The
auditory startle response is considered adequate for assessment in PND
23 males/females and PND 61 males where no treatment-related effects
were seen in auditory startle response.  Only the auditory response data
for PND 61 females is inadequate. Motor activity was examined and there
did not appear to be any differences between treated and control animals
other than decreases for multiple subsessions in PND 18 males/females at
the high dose only, but due to the high variability and the lack of
habituation, these data are considered equivocal.  If a 10-fold factor
is applied to the NOAEL in the study (i.e., 4 mg/kg bw/day) to account
for the scientific limitations of the study, the resulting value is 0.4
mg/kg bw/day.  The estimate of 0.4 mg/kg/day is similar to the doses
from the chronic dog study used for risk assessment (i.e., 0.5 mg/kg/day
for acute dietary exposure scenarios and 0.1 mg/kg/day for chronic
dietary exposure scenarios).  In the exposure databases, there are also
no residual uncertainties.  The exposure assessments are based on
reliable data and reasonable worst-case assumptions, and will not likely
underestimate risks.  There was no published literature found that would
indicate a neurodevelopmental concern for lambda-cyhalothrin.

Based on all of the considerations above, there is not a need to retain
the additional 10X safety factor for children. Application of the 10X
intraspecies uncertainty factor (which accounts for the possibility that
a subpopulation may be 10 times more sensitive than the average
individual) and a 10X interspecies factor (which accounts for the
possibility that humans may be 10 times more sensitive than animals) to
the dog NOAEL (i.e., the most sensitive species) should assure
protection of human health including children.

3.2	Absorption, Distribution, Metabolism, Excretion (ADME)  TC \l2 "3.2
Absorption, Distribution, Metabolism, Excretion (ADME)

	Metabolism studies have been conducted with cyhalothrin in both the rat
and the dog, and with lambda-cyhalothrin in the rat.  In the rat,
approximately 55% of the oral dose is absorbed.  It is extensively
metabolized when absorbed.  The urinary/fecal excretion ratio is 2.5:1.0
after subcutaneous administration.  Over 50% of the dose remained in the
carcass 7 days after a subcutaneous dose.  Metabolism results in
cleavage of the ester to cyclopropylcarboxylic acid and a phenoxybenzyl
derivative.  The distribution patterns and excretion rates in the
multiple oral dose studies are similar to the single oral dose studies.
There is accumulation of unchanged compound in the fat upon chronic
administration.  Otherwise, cyhalothrin is rapidly metabolized and
excreted.  Cyclopropyl carboxylic acid, 3-phenoxybenzoic acid,
glucuronide conjugated 3-4'-hydroxyphenoxy benzoic acid, and a sulfate
conjugate were identified in the urine.

	Cyhalothrin is taken up slowly by the fat, and released slowly.  It is
rapidly released by blood, kidneys, and liver.  The rates of metabolism
of both enantiomer pairs are likely identical (cyhalothrin and
lambda-cyhalothrin).  The absorption, distribution, metabolism, and
excretion patterns of lambda-cyhalothrin and cyhalothrin following a
single dose of 1 mg/kg in the male rat appear to be identical.

	In the dog, oral absorption of the C14 benzyl label was 80%, and
absorption of the C14 cyclopropyl label was 48%.  The metabolite
patterns for each half of the molecule were different, indicating
extensive cleavage of the ester bond.  Seven metabolites in the urine
were identified for the benzyl label, and 12 metabolites were identified
for the cyclopropyl label.  In the feces, a large proportion of the
radioactivity was due to unchanged compound.  Excretion in the urine and
feces was rapid (nearly all in 48 hours).

	Oral and dermal metabolism and pharmacokinetics studies were conducted
in humans.  Mild paresthesia of varying degrees was observed following
dermal dosing.  The minimal oral absorption was estimated to be from
50.35 to 56.71%.  The minimal dermal absorption was estimated to be from
0.115 to 0.122%.  The estimated dermal absorption value of 1% was
determined by rounding these values up to the nearest whole number.  No
metabolites were found near the limit of detection in plasma from the
oral dose study.  Blood was not analyzed from the dermal study.

3.3	FQPA Considerations  TC \l2 "3.3	FQPA Considerations

3.3.1	Adequacy of the Toxicity Database  TC \l3 "3.3.1	Adequacy of the
Toxicity Database

	Acceptable developmental studies conducted with cyhalothrin are
available in both rats and rabbits.  A 3-generation reproduction study
in rats conducted with cyhalothrin is available for FQPA consideration.
Neurotoxicity is evident throughout the toxicology database.   A DNT
study has recently been submitted, and reviewed by the Agency. The
lowest dose showing neurotoxicity in the offspring (effects on
mortality, body weight, body weight gains, learning and memory, and
brain morphometry) is 10 mg/kg bw/day.   It should be noted that some of
the parameters evaluated in this study were regarded as acceptable but
others were not (see Sections 3.1.3 and 3.3.2 for further details).  If
a 10-fold factor is applied to the NOAEL (i.e., 4 mg/kg bw/day) to
account for the scientific limitations of the study, the resulting value
is 0.4 mg/kg bw/day.   This estimate of 0.4 mg/kg/day is similar to the
doses from the chronic dog study used for risk assessment (i.e., 0.5
mg/kg/day for acute dietary exposure scenarios and 0.1 mg/kg/day for
chronic dietary exposure scenarios).  Therefore, HED concludes that
using the NOAELs from the dog study would not underestimate risks from
dietary exposure, and consequently, the FQPA safety factor can be
reduced to 1X.  In conclusion, the toxicology database is considered
complete for the purposes of the FQPA assessment.

3.3.2	Evidence of Neurotoxicity

	Neurotoxicity is evident in three species (rat, mouse, and dog), and
via all three routes of exposure in rats (oral, inhalation, and dermal).
 The neurotoxic effects observed (gait abnormalities, tremors,
convulsions, excess salivation) are common to the pyrethroid class of
pesticides.  Signs generally appear several hours after dosing, and
disappear by the next day; they are transitory in nature, and stop with
the removal of the test compound.

	The DNT in Wistar rats was conducted and submitted to the Agency (MRID
46449102); the calculated doses were 1.8, 4.3, and 10.0 mg/kg/day during
gestation and 4.0, 9.4, and 23.1 mg/kg/day during lactation.  The
maternal LOAEL was 10 mg/kg/day, based on decreased body weight, body
weight gains, and food consumption.  The maternal NOAEL was 4 mg/kg/day.
 At the highest dose tested, offspring had a 6% decrease in pre-cull
survival, a maximum of 12% decrease in body weights, the mean time to
completion of the water maze in PND 21 females was longer, the
proportion of successful trials in PND 21 females was lower than
controls for cut-off times ranging from 3-10 seconds, the group mean
success rate at 1.5 the straight channel swim time in PND 21 females was
decreased (NS), the proportion of successful trials for cut-off times
from 3-9 seconds in PND24 females were still decreased, and morphometric
measurement were affected up to a maximum13% difference compared to
controls.  Although Offspring neurotoxicity was seen with a LOAEL/NOAEL
of 10/4, a definitive LOAEL/NOAEL cannot be determined due to many data
insufficiencies.  The study is unacceptable due to an inadequate
assessment of motor activity, an inadequate assessment of auditory
startle in PND 61 females, missing low- and mid-dose morphometry data,
and statistical analyses that adjusted for body weights after treatment
had begun.

3.3.3	Developmental Toxicity Studies

	The requirements for developmental studies conducted with
lambda-cyhalothrin have been satisfied by developmental studies
conducted with cyhalothrin.  The data demonstrate no indication of
increased quantitative or qualitative sensitivity of rats or rabbits to
in utero exposure to cyhalothrin.  No developmental toxicity was
observed in either of the developmental toxicity studies in rats and
rabbits.  Maternal toxicity was observed in the form of clinical signs
of neurotoxicity in the rat study; additionally, reduced body weight
gain and food consumption were observed in both the rat and the rabbit
studies.

3.3.4	Reproductive Toxicity Study

	The requirement for a reproduction study conducted with
lambda-cyhalothrin has been satisfied by a reproduction study conducted
with cyhalothrin.  The data demonstrate no indication of increased
quantitative or qualitative sensitivity of rats to post-natal exposure
to cyhalothrin.  In the 3-generation reproduction study in rats, the
parental/offspring NOAELs are the same, based on decreased parental and
pup body weight and body weight gain.

  TC \l3 "3.3.4	Reproductive Toxicity Study

3.3.5	Pre- and/or Post-Natal Toxicity  TC \l3 "3.3.6	Pre-and/or
Postnatal Toxicity

<IP_ADDRESS>	Determination of Susceptibility

	Based on the available developmental toxicity studies in rats and
rabbits, and the 3-generation reproduction study in rats using
cyhalothrin, there is no increased quantitative or qualitative
susceptibility to fetuses exposed in utero.  TC \l4 "<IP_ADDRESS>
Determination of Susceptibility

<IP_ADDRESS>	Degree of Concern Analysis and Residual Uncertainties  TC \l4
"<IP_ADDRESS>	Degree of Concern Analysis and Residual Uncertainties

	Although the developmental and reproduction studies were conducted with
cyhalothrin, and while lambda-cyhalothrin is more refined, the degree of
concern for pre- and/or post-natal susceptibility is low.  Comparing the
LOAELs from all the toxicity studies (across four species - rat, mouse,
rabbit, dog), the LOAELs from the subchronic and chronic dog studies,
based on clinical signs of neurotoxicity, are the lowest/most
conservative doses and endpoints available.  The LOAEL from the
subchronic dog study (using cyhalothrin as the test compound) is 2.5
mg/kg/day, based on clinical signs of neurotoxicity (NOAEL = 1.0
mg/kg/day).  Studies of similar duration (subchronic, developmental, and
reproduction studies) via the oral route, show that rats were adversely
affected by cyhalothrin/lambda-cyhalothrin at doses between 5.0 – 15.0
mg/kg/day, based primarily on decreased body weights and body weight
gains.  In the subchronic mouse study, mice had decreased body weight
gain and food consumption, changes in hematology and organ weights, and
minimal centrilobular hepatocyte enlargement at a dose level of 309/294
mg/kg/day M/F, respectively.  Rabbits in the developmental study using
cyhalothrin had a LOAEL of 30 mg/kg/day, based on decreased body weight
gains and food consumption.  Over a longer duration, dogs exposed to
lambda-cyhalothrin showed clinical signs at the LOAEL of 0.5 mg/kg/day
(NOAEL = 0.1 mg/kg/day), compared to the chronic rat study which showed
decreases in body weights at 12.5 mg/kg/day and the chronic mouse study
which showed clinical signs and decreased body weight at 75 mg/kg/day.
Lambda-cyhalothrin is an enriched isomer of cyhalothrin, and many of the
cyhalothrin studies have been used to bridge the toxicology database
between the two chemicals.  Therefore, by selecting endpoints based upon
the effect of concern (neurotoxicity) in the most sensitive species
(dog) using the active ingredient lambda-cyhalothrin, the
doses/endpoints selected for risk assessment are appropriate and
protective of potential effects seen in the other species at higher dose
levels, including developmental and reproductive effects.    Since there
are no signs of increased susceptibility in rats or rabbits, the Agency
is confident that the risk to infants and children will not be
underestimated.

3.3.6	Recommendation for a Developmental Neurotoxicity Study

	HED has received a developmental neurotoxicity study (DNT) for
lambda-cyhalothrin (MRID 46449102), which was classified as
unacceptable/guideline due to inadequacies in some of the developmental
parameters tested (see DER for more details).  If a 10-fold factor is
applied to this study’s NOAEL, (i.e., 4 mg/kg bw/day) to account for
the scientific limitations of the study, the resulting value is 0.4
mg/kg bw/day.   This estimate of 0.4 mg/kg/day is similar to the doses
from the chronic dog study used for risk assessment (i.e., 0.5 mg/kg/day
for acute dietary exposure scenarios and 0.1 mg/kg/day for chronic
dietary exposure scenarios).  Therefore, HED concludes that using the
NOAELs from the dog study would not underestimate risks to infants and
children from dietary exposure, and consequently, a repeat rat DNT study
is not required.     TC \l3 "3.3.7	Recommendation for a Developmental
Neurotoxicity Study

3.3.7	Rationale for the UFDB

	As discussed in section 3.3.6, HED is confident that using the NOAELs
from the chronic dog study as the basis for the acute and chronic
dietary endpoints would not underestimate risks to infants and children,
and consequently, the FQPA safety factor can be reduced to 1X.  Thus,
the toxicology database is considered complete for the purposes of this
risk assessment, and a database uncertainty factor (UFDB) is not
required.

3.4	FQPA Safety Factor for Infants and Children

	The toxicology database is considered complete for the purposes of an
FQPA risk assessment.  Based on the developmental studies in rats and
rabbits, and the 3-generation study in rats, there is no evidence of
increased quantitative or qualitative susceptibility.  Using the NOAELs
from the chronic dog study would not underestimate risks to infants and
children.

	There are no residual uncertainties identified in the exposure
databases.  The acute and chronic dietary food exposure assessments
utilize anticipated residues based on USDA PDP monitoring data, field
trial data, and a beef-fat market basket survey.  Percent crop treated
data were used for many commodities in the analysis, although 100%CT was
assumed for new uses, and for existing uses where no further information
was available.  Although refined, the assessments are based on reliable
data, and will not underestimate exposure/risk.  The drinking water
exposure is based on conservative modeling estimates.  The residential
exposure assessment utilizes residential SOPs for the adult handler and
post-application scenarios, and to assess post-application exposure to
children, as well as incidental oral ingestion by toddlers.  The
residential SOPs are based on reasonable worst-case assumptions, and
will not likely underestimate exposure/risk.

	Based on the above hazard and exposure considerations, the FQPA safety
factor can be reduced to 1X for the current lambda-cyhalothrin risk
assessment.

3.5	Hazard Identification and Toxicity Endpoint Selection  TC \l2 "3.5
Hazard Identification and Toxicity Endpoint Selection

3.5.1	Acute Reference Dose (aRfD) – General Population

-cyhalothrin)

	MRID Number: 40027902

	Executive Summary: In a chronic toxicity study, beagle dogs (6
sex\dose) were given oral administration of gelatin capsules containing
lambda-cyhalothrin (96.5%) at 0, 0.1, 0.5, or 3.5 mg/kg/day, 7 days a
week for 12 months.  The test chemical had been dissolved in corn oil
prior to placement in the capsules.  The following parameters were
measured and/or recorded: daily clinical observations, body weights,
food consumption, ophthalmological examinations, clinical biochemistry,
urinalysis, gross necropsy, and microscopic examinations.

	No treatment-related toxicity was observed at 0.1 mg/kg/day.  At 0.5
mg/kg/day, 1 male and 1 female dog exhibited gait abnormalities, with
the effects seen in the male 7 hours post-dosing during week 2, and
again 2 days later (immediately after dosing), and in the female 4 times
during week 9.  Convulsions were seen in two other dogs (both males);
the convulsions appeared to be precipitated by the stress of handling or
noise.  At 3.5 mg/kg/day, the principal neurological clinical signs
following dosing were ataxia (all dogs, apparent from day 2 in 2 dogs,
observed 3-7 hours post-dosing), muscle tremors and convulsions,
occasional subdued behavior; worn or bleeding claws, regurgitation of
food during first 2 weeks, and fluid feces in all dogs.  Treatment had
no effect on body weights, hematology, clinical chemistry, urinalysis,
nor gross or histopathology.  The NOAEL is 0.1 mg/kg/day, and the LOAEL
is 0.5 mg/kg/day, based on clinical signs of neurotoxicity.

	This study is classified as acceptable (guideline), and satisfies the
guideline requirements for a study (83-1) in the dog.

	Dose and Endpoint for Risk Assessment: NOAEL = 0.5 mg/kg/day, based on
clinical signs of neurotoxicity (ataxia) observed from Day 2, 3-7 hours
post-dosing, seen at LOAEL = 3.5 mg/kg/day.

	Comments on Study/Endpoint/Uncertainty Factors: The endpoint selected
for assessment of acute dietary risk is appropriate because it is based
on effects that were observed within the first 2 days of exposure in an
oral study in dogs.  Based on structure-activity relationships, it is
likely that this NOAEL could be higher.  The NOAEL used for the acute
dietary endpoint is 0.5 mg/kg, with a LOAEL of 3.5 mg/kg.  With other
pyrethroids, NOAELs were closer to 1.0 mg/kg, and LOAELs were around
2.0-3.0 mg/kg.

3.5.2	Chronic Reference Dose (cRfD) – General Population  TC \l3
"3.5.3	Chronic Reference Dose (cRfD)

	Study Selected: Chronic Dog Study (lambda-cyhalothrin)

	MRID Number: 40027902

	Executive Summary: See Section 3.5.1.

	Dose and Endpoint for Risk Assessment: NOAEL = 0.1 mg/kg/day, based on
clinical signs of neurotoxicity (abnormal gait) in 2 dogs observed at
the LOAEL = 0.5 mg/kg/day.

	Comments on Study/Endpoint/Uncertainty Factors: The endpoint selected
for assessment of chronic dietary risk is appropriate because it is
based on a chronic oral study in dogs.  This NOAEL (0.1 mg/kg/day) is
somewhat lower than those seen in dog studies with other pyrethroids;
however, transient effects were observed in several dogs at 0.5
mg/kg/day.

3.5.3	Incidental Oral Exposure (Short- and Intermediate-Term)   TC \l3
"3.5.4	Incidental Oral Exposure (Short- and Intermediate-Term)

	Study Selected: Chronic Dog Study (lambda-cyhalothrin)

	MRID Number: 40027902

	Executive Summary: See Section 3.5.1.

	Dose and Endpoint for Risk Assessment: NOAEL = 0.1 mg/kg/day, based on
clinical signs of neurotoxicity (abnormal gait) in 2 dogs observed at
the LOAEL = 0.5 mg/kg/day.

	Comments on Study/Endpoint/Uncertainty Factors: This endpoint is based
on the same chronic dog study that was selected for the acute and
chronic dietary endpoints.  It is considered appropriate for both short-
and intermediate-term exposure durations because the transient effects
were observed during weeks 2 and 9.

3.5.4	Dermal Absorption

	Several dermal penetration studies are available for
lambda-cyhalothrin, one in humans, and one in rats.  The human study
indicates a dermal absorption estimate of 1%.  The rat study indicates a
dermal absorption estimate of 16%.  In the rat study, absorption ranged
from 0.24 to 15.89%.  The study authors believed that paresthesia at the
high dose caused the protective cover over the dosing site to loosen and
resulted in spreading of test material over the skin.  Thus, a
relatively high percentage of the dose was found in the carcass (16% at
24 hours exposure).

3.5.5	Dermal Exposure (All Durations)

	Study Selected: 21-Day Dermal Toxicity Study in Rats
(lambda-cyhalothrin)

	MRID Number: 44333802

	Executive Summary: In a repeated-dose dermal toxicity study (MRID
#44333802), lambda-cyhalothrin (96.6% ai) was applied to the clipped
skin of five albino rats/sex/dose at dose levels of 1 or 10 mg/kg/day
for 6 hours/day on 21 consecutive days.  Five rats/sex were similarly
treated with two or three applications at 100 mg/kg/day, reduced to 50
mg/kg/day for 21 consecutive days.

	Two males which were found dead after three applications of 100
mg/kg/day had reduced, moderately-atrophied seminal vesicles, and
slightly atrophied spleens.  Clinical signs indicative of neurotoxicity
were observed in the 100/50 mg/kg/day treatment groups.  Males exhibited
reduced splay reflex, downward curvature of the spine, splayed gait,
bizarre behavior, pinched-in sides, dehydration, reduced stability, and
thin appearance.  Females exhibited an increased incidence of tiptoe
gait, upward curvature of the spine, an increased incidence in signs of
urinary incontinence, urinary incontinence, chromodacryorrhea, and
reduced splay reflex.  The clinical signs commenced on day 2 of dosing.
Body weight gains for males were significantly reduced throughout the
study; the final gain was 58% lower than the control gain.  The final
mean body weight was 19% lower than the mean control value.  Body weight
gains for females were somewhat reduced during the first half of the
study only.  Food consumption was somewhat reduced for males throughout
the study.  No dermal irritation was observed at 100/50 mg/kg/day in
either sex.  No signs of clinical toxicity or dermal irritation in the
10 or 1 mg/kg/day treatment groups were considered to be
treatment-related.  No treatment-related differences in hematology or
clinical blood chemistry parameters, organ weights, or histopathology
were observed between the treatment and control groups.  No neoplastic
tissue was observed.  The LOAEL is 50 mg/kg/day for both sexes, based on
clinical signs of toxicity, and decreased body weight and body weight
gain.  The NOAEL is 10 mg/kg/day for both males and females.

	This dermal toxicity study is classified acceptable (82-2), and
satisfies the guideline requirement for a repeated-dose dermal toxicity
study.

	Dose and Endpoint for Risk Assessment: NOAEL = 10 mg/kg/day, based on
clinical signs of neurotoxicity (observed from Day 2), and decreased
body weight and body weight gain observed at the LOAEL = 50 mg/kg/day.

	Comments on Study/Endpoint/Uncertainty Factors: This endpoint is based
on a 21-day dermal study in the rat.  This study used the most
appropriate route of administration (dermal), and the effects of concern
(clinical signs of neurotoxicity) were observed.  Although the duration
of this study is only 21 days, it is anticipated that this study will be
protective of longer-term exposure because a comparison of the 90-day
oral study in rats with the chronic feeding study in rats indicates that
toxicity is not induced at lower dose levels when rats are exposed over
a longer period of time.  The NOAEL/LOAEL for the 90-day oral study are
2.5/12.5 mg/kg/day, based on decreased body weight gain, and the
NOAEL/LOAEL for the chronic feeding study in rats are 2.5/12.5
mg/kg/day, based on decreases in mean body weight.  No developmental
effects were observed in any of the developmental studies.  In addition,
application of the 1% dermal absorption factor to the oral NOAEL of 0.1
mg/kg/day established in the chronic dog study yields a dermal
equivalent dose of 10 mg/kg/day (0.1 ÷ 0.01 = 10.0) which is the same
dermal NOAEL used for the dermal risk assessment.  Thus, the NOAEL from
the dermal rat study is protective of effects and doses observed in
dogs.  Also, as the design of the 21-day dermal study is similar to most
of the oral studies, with respect to the neurotoxic effects of concern,
it is expected that the dermal study would detect any effects observed
in any of the oral studies.  TC \l3 "3.5.6	Dermal Exposure (Short-,
Intermediate- and Long-Term)

3.5.6	Inhalation Exposure (All Durations)

	Study Selected: 21-Day Inhalation Study in Rats (lambda-cyhalothrin)

	MRID Number: 41387702

	Executive Summary: In a 21-day inhalation study, 10/sex/dose SPF
Alpk:APfSD (Wistar-derived) albino rats were exposed nose-only 6
hours/day, 5 days/week for 21 days to lambda-cyhalothrin (81.5% pure) at
0, 0.3, 3.3, or 16.7 µg/L (estimated to be approximately 0, 0.08, 0.90,
or 4.5 mg/kg/day).  The MMAD ranged from 1.47 to 1.91 µm, and the GSD
ranged from 1.02 to 2.24 µm.

	No treatment-related effects were observed at 0.3 µg/L.  At 3.3 µg/L
the following were observed: salivation, lachrymation, paw flicking
(males only), tail erections, splayed gait (males only), decreased body
weight (94-95%, p < 0.05) and body weight gain (53-65%, p < 0.01)
relative to control values, increased incidence of punctate foci on the
cornea, slight reductions in cholesterol levels in females (p < 0.05),
decreased urine volume in males, slightly raised specific gravity of the
urine in both sexes, and reductions in urinary protein levels in males.
At 16.7 µg/L, the following were observed: salivation, lachrymation,
auditory hypoaesthesia, paw flicking, tail erection, splayed gait,
decreased activity, reduced foot withdrawal (males only), head flicking,
reduced righting reflex, shaking (males only), sides pinched in, reduced
splay reflex, decreased visual placing response, absent puma reflex
(females only), ungroomed appearance (females only), tiptoe gait (males
only), respiratory noise decreased body weight (85-88%, p <0.01) and
body weight gain (<3-14%, p < 0.01) relative to control values,
decreased food consumption (46-91% ♂, 56-87% ♀) relative to control
values, changes in selected clinical chemistry values (particularly in
females), decreased urine volume, increased urine specific gravity, and
decreased urinary protein.  There was also a slight increase in the
incidence of alveolitis in high dose females.

	The NOAEL is 0.3 µg/L (0.08 mg/kg/day), and the LOAEL is 3.3 µg/L
(0.90 mg/kg/day), based on clinical signs of neurotoxicity, decreased
body weight gains, increased incidence of punctate foci in the cornea,
slight reductions in cholesterol in females, and slight changes in
selected urinalysis parameters.

	This inhalation toxicity study is classified as acceptable
(non-guideline), and does not satisfy any particular guideline
requirement.  The study is too short for a guideline study, and
individual animal data were not provided.

	Dose and Endpoint for Risk Assessment: NOAEL = 0.3 µg/L (0.08
mg/kg/day), based on clinical signs of neurotoxicity, decreased body
weight gains, increased incidence of punctate foci in the cornea, slight
reductions in cholesterol in females, and slight changes in selected
urinalysis parameters observed at the LOAEL = 3.3 µg/L (0.90
mg/kg/day).

	Comments on Study/Endpoint/Uncertainty Factors: This endpoint is based
on a 21-day inhalation study in the rat.  This study used the most
appropriate route of administration (inhalation), and the effects of
concern (clinical signs of neurotoxicity) were observed.  No
developmental effects were observed in any of the developmental studies.
 Therefore, since the design of the 21-day inhalation study is similar
to most of the oral studies, with respect to the neurotoxic effects of
concern, it is expected that the inhalation study will reflect any other
effects observed in any of the oral studies.  Although the duration of
this study is only 21 days, it is anticipated that this study will be
protective of longer-term exposure because comparison of the 90-day oral
study in rats with the chronic feeding study in rats found that toxicity
is not induced at lower dose levels when rats are exposed over a longer
period of time.

3.5.7	Level of Concern for Margin of Exposure  TC \l3 "3.5.8	Level of
Concern for Margin of Exposure

Table 3.5.7   Summary of Levels of Concern* for Lambda-Cyhalothrin Risk
Assessment.

Route	Short-Term

(1-30 Days)	Intermediate-Term

(1-6 Months)	Long-Term

(> 6 Months)

Occupational (Worker) Exposure

Dermal	100	100	100

Inhalation	100	100	100

Residential Exposure

Dermal	100	100	100

Inhalation	100	100	100

Incidental Oral	100	100	100

* The level of concern is based upon a 10x intra-species variability
factor, and a 10x inter-species extrapolation 	factor.

3.5.8	Recommendation for Aggregate Exposure Risk Assessments

	As per FQPA, 1996, when there are potential residential exposures to a
pesticide, aggregate risk assessment must consider exposures from three
major sources: oral, dermal, and inhalation exposures.  For short-,
intermediate-, and long-term aggregate risk assessments, the oral,
dermal, and inhalation exposures can be combined in this case owing to a
common toxicity endpoint (neurotoxicity).

  TC \l3 "3.5.9	Recommendation for Aggregate Exposure Risk Assessments

3.5.9	Classification of Carcinogenic Potential

	Lambda-cyhalothrin is classified as “not likely to be carcinogenic to
humans,” based on the lack of evidence of carcinogenicity in mice and
rats.  TC \l3 "3.5.10	Classification of Carcinogenic Potential

3.5.10	Summary of Toxicological Doses and Endpoints for
Lambda-Cyhalothrin for Use in Human Risk Assessments  TC \l3 "3.5.11
Summary of Toxicological Doses and Endpoints for [Chemical] for Use in
Human Risk Assessments

Table 3.5.10a	Summary of Toxicological Doses and Endpoints for
Lambda-Cyhalothrin to be Used in Dietary and Non-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

Acute Dietary

(General Population, including Infants and Children)	NOAEL = 0.5
mg/kg/day	UFA = 10x

UFH = 10x

FQPA SF = 1x

	Acute RfD = 0.005 mg/kg/day

aPAD =0.005 mg/kg/day	Chronic Dog Study (lambda-cyhalothrin)

LOAEL = 3.5 mg/kg/day, based on clinical signs of neurotoxicity (ataxia)
observed from Day 2, 3-7 hours post-dosing.

Chronic Dietary

(All Populations)	NOAEL = 0.1 mg/kg/day	UFA = 10x

UFH = 10x

FQPA SF = 1x

	Chronic RfD = 0.001 mg/kg/day

cPAD = 0.001 mg/kg/day	Chronic Dog Study (lambda-cyhalothrin)

LOAEL = 0.5 mg/kg/day, based on clinical signs of neurotoxicity
(abnormal gait) in two dogs.

Incidental Oral Short- and Intermediate-Term (1-30 days, 1-6 months)
NOAEL = 0.1 mg/kg/day	UFA = 10x

UFH = 10x

FQPA SF = 1x

	Residential LOC for MOE < 100	Chronic Dog Study (lambda-cyhalothrin)

LOAEL = 0.5 mg/kg/day, based on clinical signs of neurotoxicity
(abnormal gait) in two dogs.

Dermal Short-Term

(All Durations)	NOAEL = 10 mg/kg/day	UFA = 10x

UFH = 10x

FQPA SF = 1x

	Residential LOC for MOE < 100	21-Day Dermal Study in Rats
(lambda-cyhalothrin)

LOAEL = 50 mg/kg/day, based on clinical signs of neurotoxicity (observed
from Day 2), and decreased body weight and body weight gain.

Inhalation Short-Term (All Durations)	NOAEL = 0.08 mg/kg/day	UFA = 10x

UFH = 10x

FQPA SF = 1x

	Residential LOC for MOE < 100	21-Day Inhalation Study in Rats
(lambda-cyhalothrin) LOAEL = 0.90 mg/kg/day, based on clinical signs of
neurotoxicity, decreased body weight gains, increased incidence of
punctate foci in the cornea, slight reductions in cholesterol in
females, and slight changes in selected urinalysis parameters.

Cancer (Oral, Dermal, Inhalation)	Classification: “not likely to be
carcinogenic to humans,” based on the absence of significant tumor
increases in two adequate rodent carcinogenicity studies.

Point of Departure (POD) = A data point or an estimated point that is
derived from observed dose-response data, and used to mark the beginning
of extrapolation to determine risk associated with lower environmentally
relevant human exposures.  NOAEL = No Observed Adverse Effect Level.
LOAEL = Lowest Observed Adverse Effect Level.  UF = Uncertainty Factor.
UFA = extrapolation from animal to human (inter-species).  UFH =
potential variation in sensitivity among members of the human population
(intra-species).  FQPA SF = FQPA Safety Factor.  PAD = Population
Adjusted Dose (a = acute, c = chronic).  RfD = Reference Dose.  MOE =
Margin Of Exposure.  LOC = Level Of Concern.

Table 3.5.10b	Summary of Toxicological Doses and Endpoints for
Lambda-cyhalothrin to be Used in Occupational Human Health Risk
Assessments.

Exposure/

Scenario	Point of Departure	Uncertainty Factors	Level of Concern for
Risk Assessment	Study and Toxicological Effects

Dermal Short-Term (All Durations)	NOAEL = 10 mg/kg/day	UFA = 10x

UFH = 10x

FQPA SF = 1x

	Occupational LOC for MOE < 100	21-Day Dermal Study in Rats
(lambda-cyhalothrin)

LOAEL = 50 mg/kg/day, based on clinical signs of neurotoxicity (observed
from Day 2), and decreased body weight and body weight gain.

Inhalation Short-Term (All Durations)	NOAEL = 0.08 mg/kg/day	UFA = 10x

UFH = 10x

FQPA SF = 1x

	Occupational LOC for MOE < 100	21-Day Inhalation Study in Rats
(lambda-cyhalothrin)

LOAEL = 0.90 mg/kg/day, based on clinical signs of neurotoxicity,
decreased body weight gains, increased incidence of punctate foci in the
cornea, slight reductions in cholesterol in females, and slight changes
in selected urinalysis parameters.

Cancer (Oral, Dermal, inhalation)	Classification:  “not likely to be
carcinogenic to humans,” based on the absence of significant tumor
increases in two adequate rodent carcinogenicity studies.

Point of Departure (POD) = A data point or an estimated point that is
derived from observed dose-response data, and used to mark the beginning
of extrapolation to determine risk associated with lower environmentally
relevant human exposures.  NOAEL = No Observed Adverse Effect Level.
LOAEL = Lowest Observed Adverse Effect Level.  UF = Uncertainty Factor.
UFA = extrapolation from animal to human (inter-species).  UFH =
potential variation in sensitivity among members of the human population
(intra-species).  FQPA SF = FQPA Safety Factor.  MOE = Margin Of
Exposure.  LOC = Level Of Concern.

3.6	Endocrine Disruption  TC \l2 "3.6	Endocrine disruption

	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 Screening 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).

	In the available toxicity studies on cyhalothrin and
lambda-cyhalothrin, there was no estrogen, androgen, and/or thyroid
mediated toxicity.

  TC \l2 "3.6	Endocrine disruption 4.0	Public Health and Pesticide
Epidemiology Data

	No public health/epidemiology data were used in developing this risk
assessment.

  TC \l2 "4.4	Other Pesticide Epidemiology Published Literature 5.0
Dietary Exposure/Risk Characterization  TC \l1 "5.0	Dietary
Exposure/Risk Characterization

5.1	Pesticide Metabolism and Environmental Degradation  TC \l2 "5.1
Pesticide Metabolism and Environmental Degradation

5.1.1	Metabolism in Primary Crops  TC \l3 "5.1.1	Metabolism in Primary
Crops

	The nature of the residue in plants is adequately understood, based on
adequate cotton, cabbage, soybean, and wheat metabolism studies.
Lambda-cyhalothrin is metabolized by cleavage of the ester linkage to
form cyclopropanecarboxylic acids and the corresponding phenoxybenzoic
acids or alcohols.  In most cases the parent compound is the principal
constituent of the residue.  However, in the cabbage metabolism study
the cis- and trans- cyclopropanecarboxylic acids were the major
constituents.  HED has concluded that the plant metabolites need not
appear in the tolerance expression at this time owing to lack of
toxicological concern, and low concentrations found from residue studies
(Memo; Pamela Hurley; 1/3/1992).  The residues to be regulated are
lambda-cyhalothrin and its epimer R157836.

5.1.2	Metabolism in Rotational Crops  TC \l3 "5.1.2	Metabolism in
Rotational Crops

	An adequate confined rotational crop study is available indicating that
significant residues (greater than 0.01 ppm) will not be present in
crops rotated 30 days after application of lambda-cyhalothrin (EFED
review; 4/6/1988).  No additional rotational crop data are required, and
no plant-back restrictions are required on the labels, based on the
non-systemic nature of lambda-cyhalothrin, and its half-life of 10-14
days (NV920006; D185478; George Herndon; 10/8/1992).

5.1.3	Metabolism in Livestock  TC \l3 "5.1.3	Metabolism in Livestock

	Studies of lambda-cyhalothrin metabolism in ruminants and poultry have
been reviewed.  Lambda-cyhalothrin is the major component of the residue
in animals, except in kidney and liver, where, in addition to the plant
metabolites,
3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2-hydroxymethyl-2-methylcyclopro
pane-carboxylic acid (OH-CPA) and 4-hydroxy-3-phenoxybenzoic acid
(4'-OH-3PBAcid) may be present in significant quantities.  A residue
transfer study, in which cows were fed dietary levels of 8, 25, or 80
ppm lambda-cyhalothrin, demonstrated that, at < 8 ppm, OH-CPA levels in
tissue would not exceed 0.01 ppm (PPs#2F4109, 2F4114, 7F3560, and
1F3992; M. Flood; 8/31/1992).  As with plants, HED has determined that
the residues to be regulated are lambda-cyhalothrin and its epimer
R157836.  The animal metabolites do not need to appear in the tolerance
expression.

5.1.4	Analytical Methodology  TC \l3 "5.1.4	Analytical Methodology

	Adequate GC/ECD methods are available for enforcing tolerances for
lambda-cyhalothrin residues in plant and animal commodities.  ICI Method
81 (PRAM 81) is available for determining residues of lambda-cyhalothrin
and its epimer in plant matrices, while ICI Method 86 (PRAM 86) is
available for determining residues of lambda-cyhalothrin and its epimer
in animal matrices.  Both methods have been validated by EPA as adequate
enforcement methods.

	For Method PRAM81, residues of lambda-cyhalothrin and R157836 are
extracted with   SEQ CHAPTER \h \r 1 acetone/hexane (1:1, v/v), and
cleaned using liquid-liquid chromatography to remove lipids, followed by
Florisil column chromatography.  Residues are then determined by GC/ECD;
the method LOQ is 0.01 ppm for both analytes.

	For Method PRAM86, residues are extracted from milk or animal tissues
with 50% acetone/hexane.  The aqueous fraction is removed, after which
the residues are then dried over sodium sulfate, and cleaned up using a
Florisil column.  Residues are determined by GC/ECD; the method LOQ is
0.01 ppm for both analytes.

	In the field trials submitted with the current petitions, residues of
lambda-cyhalothrin and R157836 were determined using GC/ECD methods,
which are more recent modifications of the current tolerance enforcement
method for plant commodities.  For the analysis of potatoes and cucurbit
vegetables, residues were extracted with acetone/hexane (1:1, v/v) and
sodium sulfate, filtered, and partitioned with aqueous sodium chloride.
Residues in the resulting hexane fraction were then cleaned up using
Florisil columns, and analyzed by GC/ECD using external standards.  The
validated LOQ is 0.01 ppm for each analyte, for a combined LOQ of 0.02
ppm.

	For the analysis of grass commodities, residues were extracted with
acetone/hexane (1:1, v/v), filtered, and cleaned up using a silica gel
solid-phase extraction (SPE) cartridge.  Residues were then analyzed by
GC/ECD using external standards.  For each grass matrix, the validated
LOQ is 0.003 ppm for lambda-cyhalothrin, and 0.007 ppm for R157836, for
a combined LOQ of 0.01 ppm.

	Each of these GC/ECD methods was adequately validated in conjunction
with the analysis of field trial samples using fortified control
samples.  Recoveries of lambda-cyhalothrin averaged 89-96% (with
standard deviations of 10-13%) from cucurbit vegetables, 85-93% (s.d.
14-17%) from grass commodities, and 90% (s.d. 10%) from potatoes.
Recoveries of R157836 averaged 87-99% (s.d. 8-15%) from cucurbit
vegetables, 80-95% (s.d. 11-18%) from grass commodities, and 91% (s.d.
11%) from potatoes.  Apparent residues were less than the LOQ in most
controls samples, and where apparent residues were above the LOQ in
control samples, the residues were substantially less than the residues
in the associated treated samples.

5.1.5	Environmental Degradation

	The environmental fate database for lambda-cyhalothrin is substantially
complete, but it contains various supplemental studies.
Lambda-cyhalothrin is expected to have little mobility in soil surfaces
and, therefore, leaching into groundwater is not expected to be an
important environmental fate process (average KOC = 354,100; n = 10).
Volatilization from moist or dry surfaces is not expected to be an
important transport process.  Lambda-cyhalothrin has a relatively low
vapor pressure and Henry’s Law constant (1.5 x 10-9 mm Hg and 2.4 x
10-7 Atm-cm3/mole, respectively).  With a pKa > 9, lambda-cyhalothrin is
expected to be neutral in natural environments, but will be affected in
alkaline environments.

	Lambda-cyhalothrin is moderately persistent in the environment, and
degrades slowly through a combination of biotic and abiotic mechanisms.
Lambda-cyhalothrin is stable in acidic and neutral water, but hydrolyzes
under alkaline conditions (half-life of 13 days at pH 9).
Lambda-cyhalothrin is more stable to light than the first or second
generation pyrethroids like allethrin and resmethrin, but still
undergoes some photolysis in water, with half-lives of about a month or
more in distilled water (half-life 25 days).  On soil, the half-life is
fairly stable (with little degradation on the order of ~13% in 35 days).
 It appears that the alpha cyano group stabilizes the molecule, and it
does not undergo photolysis readily.  Under both aerobic and anaerobic
soil metabolism conditions, lambda-cyhalothrin biodegrades at moderate
rates, with half-lives ranging from 12 to 72 days, but in aquatic
metabolism conditions, it biodegrades more slowly, with half-lives on
the order of about 113-142 days.  Terrestrial field dissipation studies
indicate that a combination of these mechanisms of dissipation take
place.  Half-lives of 12-64 days were observed in the field.

	Indications are that, for synthetic pyrethroids with similar structure
to that of lambda-cyhalothrin, dissipation from plant foliage occurs
with half-lives on the order of 5-6 days, but it may be higher for the
total residues.  A low rate of volatilization was observed from leaves,
with 88% of the compound applied remaining on the leaves after 24 hours
(European Commission Review Report for the Active Substance
Lambda-Cyhalothrin; 7572/VI/97-final; 1/25/2001).  The chemical does not
translocate in the plant tissue.  Lambda-cyhalothrin is expected to be
immobile in soil environments.  Due to its low mobility, it is highly
unlikely to reach ground waters.  However, despite the protective
imposed buffer zone and buffer strip, it could reach adjacent surface
waters via spray drift or runoff events (via erosion).  Once there, the
chemical will partition with the sediment, and will linger for long
periods of time (months).  The sediment serves as a repository of the
chemical after numerous applications, in dynamic equilibrium with the
pore water and the surface water.

	Lambda-cyhalothrin is moderately bioaccumulative (448X in the whole
body), but it depurates slowly (only 10-15% depuration after 21 days).
It appears that situations may occur where this chemical may persist in
fish tissue for extended periods of time.

	The (±) cis- or
trans-3-(2-trifluoromethyl-2-chloro-ethenyl)-2,2-dimethylcyclopropane
carboxylic acid and 3-phenoxybenzaldehyde are the result of the
hydrolysis of the ester linkage of the pyrethroid structure.  However,
in general, the major degradates appear to be (±)cis- or
trans-3-(2-trifluoromethyl-2-chloro-ethenyl)-2,2-dimethylcyclopropane
carboxylic acid and 3-phenoxy-benzoic acid (3-PBA, or 3-PBacid, the
oxidation product of 3-phenoxybenzaldehyde).  It appears that
3-phenoxybenzaldehyde oxidizes quickly to 3-PBA.  The findings in the
field corroborate the laboratory predictions.

	Ring-hydroxylated lambda-cyhalothrin, degradate XV (see Table B.1 in
Appendix B), formed in aerobic soil microbial degradation (12% of the
applied compound at 63 days post-treatment), was included in the
drinking water assessment due to its potential toxicological concerns in
humans.  This degradate appears to degrade readily to carbon dioxide
(average t1/2 = 8.9 days; n = 3), and it appears to partition with the
sediment.  It has low mobility based on the estimated KOC value of
770,900 mL/gOC from structure activity relationship (SAR) modeling.  The
potential for groundwater contamination by this degradate is low.
However, it is likely to reach surface water via runoff (through
erosion) after a rainfall event.

5.1.6	Comparative Metabolic Profile

	Metabolism studies have been conducted with cyhalothrin in both the rat
and the dog, and with lambda-cyhalothrin in the rat.  In the rat,
approximately 55% of the oral dose is absorbed.  It is extensively
metabolized when absorbed.  The urinary/fecal excretion ratio is 2.5:1.0
after subcutaneous administration.  Over 50% of the dose remained in the
carcass 7 days after a subcutaneous dose.  Metabolism results in
cleavage of the ester to cyclopropylcarboxylic acid and a phenoxybenzyl
derivative.  The distribution patterns and excretion rates in the
multiple oral dose studies are similar to the single oral dose studies.
There is accumulation of unchanged compound in the fat upon chronic
administration.  Otherwise, cyhalothrin is rapidly metabolized and
excreted.  Cyclopropyl carboxylic acid, 3-phenoxybenzoic acid,
glucuronide conjugated 3-4'-hydroxyphenoxy benzoic acid, and a sulfate
conjugate were identified in the urine.

	Cyhalothrin is taken up slowly in fat, and released slowly.  It is
rapidly released by blood, kidneys, and liver.  The rates of metabolism
of both enantiomer pairs are likely identical (cyhalothrin and
lambda-cyhalothrin).  The absorption, distribution, metabolism, and
excretion patterns of lambda-cyhalothrin and cyhalothrin following a
single dose of 1 mg/kg in the male rat appear to be identical.

	In the dog, oral absorption of the C14 benzyl label was 80%, and
absorption of the C14 cyclopropyl label was 48%.  The metabolite
patterns for each half of the molecule were different, indicating
extensive cleavage of the ester bond.  Seven metabolites in the urine
were identified for the benzyl label, and 12 metabolites were identified
for the isopropyl label.  In the feces, a large proportion of the
radioactivity was due to unchanged compound.  Excretion in the urine and
feces was rapid (nearly all in 48 hours).

	Metabolism in plants and livestock (ruminants and poultry) also
involves cleavage of the ester, resulting in formation of
cyclopropylcarboxylic acid (CPA) and phenoxybenzyl derivatives.  In
kidney and liver, the metabolites OH-CPA and 4-hydroxy-3-phenoxybenzoic
acid may be present in significant quantities.

	Oral and dermal metabolism and pharmacokinetics studies were conducted
in humans.  Mild paresthesia of varying degrees was observed following
dermal dosing.  The minimal oral absorption was estimated to be from
50.35 to 56.71%.  The minimal dermal absorption was estimated to be from
0.115 to 0.122%.  The estimated dermal absorption value of 1% was
determined by rounding these values up to the nearest whole number.  No
metabolites were found near the limit of detection in plasma from the
oral dose study.  Blood was not analyzed from the dermal study.

5.1.7	Drinking Water Residue Profile TC \l3 "5.1.9	Drinking Water
Residue Profile

Table 5.1.7	Summary of Estimated Drinking Water Concentrations (EDWCs)
for Lambda-			Cyhalothrin.

Drinking Water Source[Model Used 1]	Use/Application Method[Rate Modeled]
Lambda-cyhalothrin EDWCs (ppb)	Degradate of Concern, XV EDWCs (ppb)
Total EDWCs (ppb)

Groundwater [SCI-GROW 2]

Acute and Chronic	Orchards/Ground and Aerial [0.5 lb/A]	0.00300	0.000360
0.00336

Surface Water [FIRST 3] Acute	Orchards/Ground [0.5 lb/A]	5.00	0.350	5.35

	Orchards/Aerial [0.5 lb/A]	5.00	0.298	5.30

Surface Water [FIRST] Chronic	Orchards/Ground [0.5 lb/A]	0.122	0.00758
0.130

	Orchards/Aerial [0.5 lb/A]	0.117	0.00645	0.123

1. The estimated concentrations provided in this assessment are
conservative estimates of concentrations in drinking 	water.  If dietary
risks require refinement, higher-tiered crop-specific and
location-specific models and 	modeling scenarios can be utilized.

2. The SCI-GROW (Screening Concentration In GROund Water) concentration
(ppb) represents the groundwater 	concentration that might be expected
in shallow unconfined aquifers under sandy soils. Output is used for
both acute and chronic endpoints.

3. The FIRST (FQPA Index Reservoir Screening Tool) concentrations (ppb)
represent untreated surface water 	concentrations.  The peak day
concentration 	(over 30 years) is used for acute endpoints, and the
annual 	average concentration (over 30 years) is used for chronic
endpoints.

	The drinking water residues used in the dietary risk assessment were
provided by EFED in a memorandum (D324222, D330149; Jose Melendez;
10/26/2006), and incorporated directly into the dietary assessment.
Water residues were incorporated into DEEM-FCID via the food categories
“water, direct, all sources” and “water, indirect, all sources.”

	The analysis is a Tier I level drinking water analysis conducted using
the FIRST model; refinements may be available should they be needed.
The acute level in surface drinking water was 5.35 ppb of
lambda-cyhalothrin and degradate XV; the chronic level in drinking water
was 0.130 ppb of lambda-cyhalothrin and degradate XV.  It was assumed
that the maximum application rate was used on orchards via ground
applications, with the minimum interval between applications (assumed to
be seven days).  The groundwater concentration of lambda-cyhalothrin and
degradate XV, suitable for acute and chronic purposes is 0.00336 ppb.
The results are based on applications of lambda-cyhalothrin at the
maximum use rate to orchards.

	Comparison of results for aerial or ground applications yielded a
higher chronic concentration of lambda-cyhalothrin from the 4 ground
applications, as opposed to the 5 aerial applications.  It also yielded
higher acute and chronic results from the ground applications for the
transformation product XV.  The high use rate of the ground application
is more important than the high level of drift of the aerial
applications.  In both cases, the peak concentration was limited by the
solubility of the chemical (s = 5 ppb).

	There are weaknesses in the data base, owing to the fact that some of
the studies are supplemental, and part of the data set for XV was
modeled through SAR; however, this is considered a conservative
(screening-level) drinking water analysis.

	SCI-GROW (Screening Concentration in Ground Water) provides the
following warning: estimated concentrations of chemicals with KOC values
greater than 9995 ml/g are beyond the scope of the regression data used
in SCI-GROW development.  If there are concerns for such chemicals, a
higher-tier groundwater exposure assessment should be considered,
regardless of the concentration returned by SCI-GROW.  The KOC input
value for lambda-cyhalothrin was 301,500 ml/g, and for its degradate,
XV, it was 770,900 ml/g.  Given that the KOC of both lambda-cyhalothrin
and the degradate, XV, are far outside the range of the KOC values used
to develop SCI-GROW, there may be high uncertainty regarding the
estimated ground water concentrations for drinking water consumption.

	There is a problem with the material balance in this assessment.  By
nature, the approach taken to estimate the parent plus degradate will
yield higher concentrations than the actual concentrations should there
be a real material balance.  This occurs because the degradate is
modeled “in addition” to the parent.  Nevertheless, EFED considers
the approach suitable for a Tier I screening-level assessment, using
Tier 1 aquatic models. Should additional refinements be required, EFED
may explore a different approach.

5.1.8	Food Residue Profile  TC \l3 "5.1.10	Food Residue Profile

	Residue chemistry issues relevant to the proposed new uses requested in
the current petitions were reviewed in the Summary of Analytical
Chemistry and Residue Data memorandum for lambda-cyhalothrin (D313315;
William T. Drew; 12/27/2006).

	In the field trials submitted with the current petitions, the maximum
frozen storage durations were 2.9-3.6 months for muskmelons, cucumbers,
and squash, 3 months for potatoes, and 8.5 months for grass forage, hay,
straw, and seed screenings.  The available storage stability data
support the storage conditions and durations for samples from the
current field trials and processing studies.

	Adequate cattle and poultry feeding studies, and a cattle dermal
application study are available to support the existing and proposed
uses.  Based on the existing and recommended tolerances for plant
commodities, the calculated TDB for lambda-cyhalothrin residues is 10.6
ppm for beef cattle, 10.4 ppm for dairy cattle, 0.9 ppm for swine, and
1.0 ppm for poultry.  Using these TDBs and the available livestock
residue data, the maximum expected lambda-cyhalothrin residues in cattle
commodities are 0.35 ppm in whole milk (reflecting 8.8 ppm in milk fat),
2.5 ppm in fat, 0.11 ppm in muscle, 0.06 ppm in liver, and 0.15 ppm in
kidney. The maximum expected residues in hog commodities would be 0.16
ppm in fat, 0.006 ppm in meat, and 0.011 ppm in meat-byproducts.  The
maximum expected residues in poultry commodities would be 0.003 ppm in
eggs, 0.022 ppm in fat, 0.002 ppm in meat, and 0.003 ppm in
meat-byproducts.  These residue levels indicate that the current
tolerances in poultry commodities, as well as in the fat, meat, and meat
by-products of cattle, goats, horses, and sheep, are all adequate.
However, the tolerance should be increased in milk fat (from 5 ppm to 10
ppm).  The data also indicate that the current tolerances in hog
commodities could be lowered to 0.2 ppm in fat, 0.01 ppm in meat, and
0.02 ppm in meat-byproducts.

	Adequate confined rotational crop data are available indicating that
rotational crop restrictions and tolerances are not required for the
current or proposed uses.

	The available field trial data on potatoes, cucumbers, muskmelons,
summer squash, and grasses are adequate, and support the proposed use
patterns for lambda-cyhalothrin (CS) on tuberous and corm vegetables,
cucurbit vegetables, and grasses.  The number and geographic
distribution of the field trials are adequate, and the appropriate
samples were collected at the proposed PHIs.  Following four broadcast
foliar applications of lambda-cyhalothrin (CS) to potatoes (during tuber
development) at the 1x rate, combined residues of lambda-cyhalothrin and
R157836 were less than the LOQ (<0.02 ppm) in all potato samples
harvested at the proposed 7-day PHI.  Following six broadcast foliar
applications of lambda-cyhalothrin (CS) to representative cucurbit
vegetables (during fruit development) at the 1x rate, combined residues
at the proposed 1-day PHI were <0.02-<0.03 ppm in muskmelons and
cucumbers, and <0.02-<0.04 ppm in summer squash.  Following single
broadcast applications of lambda-cyhalothrin (CS) to grasses at the 1x
rate, combined residues were 0.13-8.04 ppm in forage harvested at 0-3
days after treatment (DAT), and <0.01-6.01 ppm in hay harvested at 5-11
DAT.  Following a single application at the 1x rate to grasses grown for
seed, combined residues were 0.35-7.80 ppm in straw, and 0.80-3.23 ppm
in seed screenings harvested at maturity, 7-19 DAT.

	In addition to the new field trial data, adequate field trial data are
available on rice, wheat, almonds, and pecans from previously reviewed
petitions.  The data on rice will be translated to support an identical
use on wild rice; the data on almonds and pecans will be translated to
support an identical use on pistachios; and the data on wheat will be
translated to support identical uses on barley, buckwheat, oats, and
rye.

	Adequate processing studies are available for potato and wheat grain;
processing data are not required for cucurbit vegetables, grass, nor
wild rice.  Based on residues in potatoes (less than the LOQ) treated at
a 5x rate, residues are unlikely to be detectable in processed
commodities from potatoes treated at 1x; therefore, separate tolerances
are not required for potato processed fractions.  However, based on the
available wheat grain processing data, in which residues concentrated by
3x in bran, separate tolerances are required for both barley and rye
bran, each at 0.2 ppm.

International Residue Limits TC \l3 "5.1.11	International Residue Limits

	The Codex Alimentarius Commission, Mexico, and Canada have all
established maximum residue limits (MRLs) for residues of
lambda-cyhalothrin in/on a variety of raw agricultural commodities.
These regulatory bodies express residues in terms of only cyhalothrin
(Codex) or of lambda-cyhalothrin (Canada, Mexico); none of these
tolerances include the epimer R157836 found in the U.S. tolerance
expression.  EPA includes the epimer due to it being considered as toxic
as the active ingredient and its presence at quantifiable levels in many
crops.    For the crop uses currently under consideration, only potatoes
have existing international tolerances.  Although the recommended 0.02
ppm U.S. tolerance agrees numerically with the Codex and Mexican MRLs,
strictly speaking they are not in harmony due to the different residue
definitions.

Dietary Exposure and Risk TC \l2 "5.2  Dietary Exposure and Risk

Acute and chronic dietary (food + drinking water) exposure analyses were
conducted using the Dietary Exposure Evaluation Model (DEEM-FCID™,
Version 2.03) which uses food consumption data from USDA’s CSFII from
1994-1996 and 1998.  The dietary exposure analyses were explicated in
the Acute and Chronic Dietary (Food and Drinking Water) Exposure and
Risk Assessment memorandum for lambda-cyhalothrin (D324223; Anant
Parmar; 3/12/07).

DEEM-FCID™ default factors or, where available, factors from
processing studies) and %CT estimates provided by BEAD.  The estimated
maximum %CT (where available) for each commodity was used in the acute
dietary risk assessment; where no further information was available, and
for new uses, 100%CT was assumed.  Acute anticipated residues were
derived from PDP monitoring data, field trial studies, and a market
basket survey for beef-fat.

	The Estimated Drinking Water Concentrations (EDWCs) for
lambda-cyhalothrin were derived from calculations based on a maximum
application rate of 0.5 lb ai/A per season to orchards (ground
application) to obtain surface water concentrations. The acute drinking
water concentration in surface water of 5.35 ppb was based on the FIRST
estimated peak concentration.

	The acute dietary exposure estimates for food and drinking water are
below HED’s LOC, 100% of the aPAD, at the 99.9th percentile of
exposure, for the general US population and all population subgroups.
Lambda-cyhalothrin acute dietary exposure at the 99.9th percentile for
food and drinking water is 46% of the aPAD for the general US
population, and 61% of the aPAD for all infants (<1 year old), the most
highly-exposed population subgroup.

Table 5.2.1	Lambda-Cyhalothrin Acute Dietary (Food + Drinking Water)
Exposure Analysis.

Population Subgroup*	aPAD (mg/kg/day)	95th Percentile	99th Percentile
99.9th Percentile

Exposure Estimate (mg/kg/day)	% aPAD	Exposure Estimate (mg/kg/day)	%
aPAD	Exposure Estimate (mg/kg/day)	% aPAD

General US Population	0.005	0.000662	13%	0.001134	23%	0.002275	46%

All Infants

<1 year old	0.005	0.001308	26%	0.001855	37%	0.003031	61%

Children

1-2 years old	0.005	0.001166	23%	0.001732	35%	0.002714	54%

Children

3-5 years old	0.005	0.000908	18%	0.001403	28%	0.002534	51%

Children

6-12 years old	0.005	0.000619	12%	0.000933	19%	0.001602	32%

Youth

13-19 years old	0.005	0.000431	9%	0.000792	16%	0.002009	40%

Adults

20-49 years old	0.005	0.000614	12%	0.001136	23%	0.002636	53%

Adults

50+ years old	0.005	0.000434	9%	0.000793	16%	0.001455	29%

Females

13-49 years old 	0.005	0.000453	9%	0.000831	17%	0.001567	31%

* Values for the population with the highest risk are in bold type.

5.2.2	Chronic Dietary Exposure/Risk  TC \l3 "5.2.2  Chronic Dietary
Exposure/Risk

DEEM-FCID™ default factors or, where available, factors from
processing studies) and %CT estimates provided by BEAD.  The estimated
weighted average %CT (where available) for each commodity was used in
the chronic dietary risk assessment; where no further information was
available, and for new uses, 100%CT was assumed.  Chronic anticipated
residues were derived from PDP monitoring data, field trial studies, and
a market basket survey for beef-fat.

	The chronic drinking water concentration in surface water of 0.130 ppb
was based on the FIRST estimated mean concentration resulting from a
maximum application rate of 0.5 lb ai/A per season to orchards (ground
application).

	The chronic dietary exposure estimates for food and drinking water are
below HED’s LOC, 100% of the cPAD, for the general US population and
all population subgroups.  Lambda-cyhalothrin chronic dietary exposure
for food and drinking water is 17% of the cPAD for the general US
population, and 50% of the cPAD for children (1-2 yrs old), the most
highly-exposed population subgroup.

Table 5.2.2	Lambda-Cyhalothrin Chronic Dietary (Food + Drinking Water)
Exposure Analysis.

Population Subgroup*	cPAD (mg/kg/day)	Exposure Estimate (mg/kg/day)	%
cPAD*

General U.S. Population	0.001	0.000173	17%

All Infants <1 year old	0.001	0.000222	22%

Children 1-2 years old	0.001	0.000503	50%

Children 3-5 years old	0.001	0.000367	37%

Children 6-12 years old	0.001	0.000222	22%

Youth 13-19 years old	0.001	0.00013	13%

Adults 20-49 years old	0.001	0.000153	15%

Adults 50+ years old	0.001	0.000125	13%

Females 13-49 years old	0.001	0.000121	12%

* Values for the population with the highest risk are in bold type.

5.2.3	Cancer Dietary Risk  TC \l3 "5.2.3  Cancer Dietary Risk

Lambda-cyhalothrin is classified as “not likely to be carcinogenic to
humans.”  As such, while acute and chronic dietary analyses are
required, there is no cancer risk associated with the existing or
proposed uses.

5.3	Anticipated Residue and Percent Crop Treated (%CT) Information TC
\l2 "5.3 Anticipated Residue and Percent Crop Treated (%CT) Information

	The registrant supported new uses on barley, oats, rye, wild rice,
buckwheat, cucurbit vegetables (crop group 9), grass forage and hay
(crop group 17), and tuberous and corm vegetables (crop group 1C).  New
field trials were carried out on potatoes, cantaloupes, cucumbers,
summer squash, and a variety of grasses.  A market basket survey was
provided by Syngenta for beef fat.  Adequate PDP monitoring data are
available for the following commodities: apples, broccoli, cauliflower,
lettuce, onions, peaches, pears, sweet bell peppers, soybeans, wheat,
sweet corn, sweet peas, and butter.  Tolerance level values were used
for the following commodities: okra, eggplant, poultry, tree nuts group
(crop group 14) except almonds and pecans, and tuberous and corm
vegetables subgroup (crop group 1C) except potatoes.

	The screening-level estimates of agricultural uses for
lambda-cyhalothrin were provided by BEAD in the form of a
screening-level usage assessment (SLUA), based on data years 1999-2004
(SLUA; A. Halvorson; 9/17/2006).  The estimated maximum %CT for each
commodity was used in the acute dietary risk assessment, and the
estimated weighted average %CT for each commodity was used in the
chronic dietary risk assessment.  Where no further information was
available, and for new uses, 100%CT was assumed.

6.0	Residential (Non-Occupational) Exposure/Risk 	Characterization

	Lambda-cyhalothrin uses currently include ornamental gardens, lawns,
landscapes, turf, golf courses, and general insect control (spot
treatments, and crack and crevice treatments) in, around, and on
buildings, structures, and immediate surroundings.  A review of current
labels indicates that all products, except for one aerosol can product,
are limited to use only by certified applicators.  As such, this
assessment addresses the single residential handler scenario for aerosol
can users, and post-application scenarios associated with any use in a
residential environment.  It should be noted that the residential
exposure/risk assessment is based on existing uses for
lambda-cyhalothrin because all potential residential exposures must be
considered in the calculation of aggregate risks.

	A non-occupational (residential) exposure assessment for
lambda-cyhalothrin was completed in 1997 (D238737; Pamela Hurley et al;
11/14/1997).  In the 1997 pyrethroid assessment, owing to the wide
variety of residential uses, it was agreed that flea control
(simultaneous use on pets, lawns, and indoor surfaces) would serve as a
screening-level scenario for all residential uses because it was
anticipated to represent the highest potential for residential exposure.
 However, at that time, lambda-cyhalothrin uses did not include indoor
surfaces or pets, so only exposure estimates pertaining to the lawn uses
were used as appropriate in the 1997 assessment for lambda-cyhalothrin.

	The 1997 lambda-cyhalothrin assessment served as the basis for the
current risk calculations, which were taken from the most recent
(D284860; Kit Farwell; 8/15/2002) lambda-cyhalothrin human health risk
assessment, and detailed in the associated occupational and residential
exposure (ORE) assessment (D280103; Margarita Collantes; 8/14/2002).
The only modifications have been adjusting the values from the 1997
assessment for appropriate absorption factors.  This represents a
definitive screening-level approach because since that time the Agency
has engaged in a series of revisions to its Standard Operating
Procedures (SOPs) for Residential Exposure Assessments (the latest on
2/22/2001).  Incorporating the revisions to the SOPs would only refine
the exposure estimates (in all cases MOEs would be higher).

6.1   Handler tc \l3 "4.5.1   Handler

	For the residential assessment, existing uses on turf, in gardens, on
golf courses, and for structural pest control were considered, but a
quantitative calculation was only completed for post-application
exposure on treated turf.  The Agency used a conservative
screening-level approach to address the risks associated with the use of
the aerosol can product of lambda-cyhalothrin that can be purchased and
used by homeowners.

	In this case, a screening-level quantitative calculation was only
completed for post-application exposure on treated turf because this
scenario is expected to have the highest associated exposures of all
residential exposures (see Section 6.2, below, for more details on the
post-application assessment).  In other words, this is a lower tier
approach, and HED believes that the selected post-application assessment
on lawns for children is protective for all residential exposures (even
the aerosol can handler scenario) because the dose levels for children
playing on treated lawns are thought to exceed those expected for all
other scenarios (lawn exposures for children represents the worst case
scenario).  This approach is based on the following conservative
considerations:

(1) HED assumed that children contacted lawns immediately after
application of lawn product and thus there was no dissipation of
residues from the treated lawn,

	(2) HED estimated dermal exposure based on a high duration of exposure
on the lawn and an intensity of activity that results in a high degree
of contact with the treated lawn,

		(3) HED assumed that the pesticide was applied at the maximum
application rate,

	(4) post-application oral exposure for children on lawns was also
calculated, which resulted in MOEs that are not of concern (aggregate
MOE = 500); this approach is thought to provide conservative estimates
of exposure and it is not a route of consideration for adult handlers.

As noted in Section 6.2 of this document, all residential
(non-occupational) MOEs calculated using this screening-level approach
were well above the target MOE of 100.

6.2   Post-Application tc \l3 "4.5.2   Postapplication

	The Agency uses the term “post-application” to describe exposure of
individuals that occurs as a result of being in an environment that has
been previously treated with a pesticide.  Lambda-cyhalothrin can be
used in many areas that could be frequented by the general population,
including residential areas such as lawns.  As a result, individuals can
be exposed by entering these areas if the areas have been previously
treated.

	The post-application assessment for treatment on lawns is based on a
screening-level approach, in which children’s and adults’ exposures
to treated turf were selected as representing the highest anticipated
exposure scenarios.  In this case, the Agency believes that exposures
associated with contact to treated turf represent the high-end exposure
scenario.  Adults and children of varying ages can potentially be
exposed to dermal and inhalation routes of exposure when they contact
previously treated turf.  Children may also be exposed by incidental
non-dietary ingestion of turf.  Each of these elements was considered in
the calculation of post-application exposure to lambda-cyhalothrin on
turf.  The residential MOEs were aggregated together because, regardless
of the exposure route (dermal, inhalation, or oral), lambda-cyhalothrin
has similar adverse effects (neurotoxicity).

	All residential (non-occupational) MOEs calculated using this
screening-level approach were well above the Agency target MOE of 100
for the inhalation, dermal, and oral routes (ranging from 700 to
15,000), and therefore do not exceed HED’s level of concern.
Furthermore, when total MOEs were calculated (all routes added
together), MOEs still were not of concern (MOEs for children were 460 to
500, and the MOE for adults was 3000).

	A quantitative post-application risk assessment for termiticide use was
not performed for this use.  Since the lambda-cyhalothrin used as a
termiticide (in the form of Impasse® Barrier) is placed under the
foundation (poured concrete) of houses, the potential for dermal
exposure is negligible.  The potential for post-application inhalation
exposure is also expected to be extremely minimal due to the vapor
pressure for lambda-cyhalothrin being very low (1.5 x 10-9 mm Hg).  HED
does not anticipate any significant air concentrations of
lambda-cyhalothrin accumulating.

Table 6.2	Lambda-Cyhalothrin Residential Risk Calculations tc \l3 "
     Table 6.   Residential Risk .

Population Subgroup	Inhalation	Dermal	Oral	Total

MOE 4

	Exposure (mg/kg/day)	MOE 1	Exposure (mg/kg/day)	MOE 2	Exposure
(mg/kg/day)	MOE 3

	Adults	5.46E-06	15,000	2.6E-03	3800	NA 5	NA	3,000

Children [1-6 years]	1.35E-05	5,900	4.96E-03	2000	1.34E-04	750	500

Infants [<1 year]	1.68E-05	4,800	5.12E-03	2000	1.43E-04	700	460

1. Inhalation MOE = inhalation NOAEL (0.08 mg/kg/day) ( inhalation
exposure (mg/kg/day).

2. Dermal MOE = dermal NOAEL (10 mg/kg/day) ( dermal exposure
(mg/kg/day).

3. Oral MOE = oral NOAEL (0.1 mg/kg/day) ( oral exposure (mg/kg/day).

4. Total MOE = 1/[(1/dermal MOE) + (1/inhalation MOE) + (1/oral MOE)].

5. NA = Not Applicable.

6.3   Spray Drift tc \l3 "4.5.3   Spraydrift

	Spray drift is a potential source of exposure for residents living in
close proximity to spraying operations.  This situation is particularly
the case with aerial application.  However, to a lesser extent, spray
drift resulting from the ground application of lambda-cyhalothrin could
also be a potential source of exposure.  The Agency has been working
with the Spray Drift Task Force (a membership of US pesticide
registrants), EPA Regional Offices, State Lead Agencies for pesticide
regulation, and other parties to develop the best spray drift management
practices.  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, 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, and risks associated with pesticide application.

7.0	Aggregate Risk Assessments and Risk Characterization

 TC \l2 "7.1	Acute Aggregate Risk 	Aggregate risk includes exposure from
non-occupational sources, including exposure from drinking water, food,
and residential pathways.  Residential exposure routes include dermal,
inhalation, and incidental oral exposure (hand-to-mouth-type inadvertent
exposure).

7.1	Acute Aggregate Risk

	For acute aggregate risk assessments, contributions to risk include
food and water exposures.  Residential exposure is not assessed for this
time period.  Therefore, the acute aggregate exposure and risk estimates
are equivalent to the acute dietary exposure and risk estimates
discussed in Section 5.2.1, and do not exceed HED’s LOC.

7.2	Short- and Intermediate-Term Aggregate Risk tc \l2 "5.2  Short- and
Intermediate-Term Aggregate Risk

	Aggregate risk for short- and intermediate-term durations of exposure
includes food, drinking water, and residential exposure pathways.  	In
estimating short- and intermediate-term aggregate risk, HED combines the
chronic dietary (food and drinking water) exposure estimate, and the
total non-dietary (residential) exposure estimate for adults and
children.  The chronic dietary exposure estimate reflects average
dietary exposure, and serves as an estimate of dietary exposure that
co-occurs with potential short- and intermediate-term non-dietary
exposure to adults and children.  The residential exposure pathway
includes dermal, inhalation, and incidental oral (hand-to-mouth-type
inadvertent exposure) routes of exposure.  This aggregate risk
assessment incorporates lawn post-application exposure (the scenario
with the highest potential for exposure), and is a day-0 screening-level
assessment.  The resulting aggregate MOEs were greater than the Agency
target MOE of 100 (ranging from 140 to 490), and there were thus no
concerns for aggregate exposure.

  SEQ CHAPTER \h \r 1 TABLE 7.2	Lambda-Cyhalothrin Short- and
Intermediate-Term Aggregate Risk Calculations.

Population Subgroup	Dietary Exposure Estimate 1

(mg/kg/day)	Dietary

MOE 2	Inhalation MOE	Dermal MOE	Oral MOE	Aggregate MOE 3

(Dietary and

Residential)

Adults	0.000173	580	15,000	3800	NA 4	490

Children [1-2 years]	0.000503	200	5,900	2000	750	140

Infants [<1 year]	0.000222	450	4,800	2000	700	230

1. Dietary exposure = [food exposure + drinking water exposure].

2. Dietary MOE = dietary NOAEL (0.1 mg/kg/day) ( dietary exposure
(mg/kg/day).

3. Aggregate MOE = 1/[(1/dermal MOE) + (1/inhalation MOE) + (1/oral MOE)
+ (1/dietary MOE)].

4. NA = Not Applicable.

7.3	Long-Term Aggregate Risk  tc "7.4	Long-Term Aggregate Risk " \l 2

	The dietary exposure (food and drinking water) pathway is the only
source of exposure to lambda-cyhalothrin that is expected to be of long
term (180 to 365 days).  Therefore, the long-term aggregate exposure and
risk estimates are equivalent to the chronic dietary exposure and risk
estimates discussed in Section 5.2.2, and do not exceed HED’s LOC.

7.4	Cancer Aggregate Risk

Lambda-cyhalothrin is classified as “not likely to be carcinogenic to
humans.”  Therefore, there is no aggregate cancer risk associated with
the existing or proposed uses.

8.0	Cumulative Risk Characterization/Assessment

	Lambda-cyhalothrin is a member of the pyrethroid class of pesticides.
Although all pyrethroids alter nerve function by modifying the normal
biochemistry and physiology of nerve membrane sodium channels, EPA is
not currently following a cumulative risk approach (based on a common
mechanism of toxicity) for the pyrethroids. Although all pyrethroids
interact with sodium channels, there are multiple types of sodium
channels, and it is currently unknown whether the pyrethroids have
similar effects on all channels.  Nor is there a clear understanding of
effects on key downstream neuronal function (nerve excitability), nor do
we understand how these key events interact to produce their compound
specific patterns of neurotoxicity.  There is ongoing research by the
EPA’s Office of Research and Development (and pyrethroid registrants)
to evaluate the differential biochemical and physiological actions of
pyrethroids in mammals.  When available, the Agency will consider this
research, and make a determination of common mechanism as a basis for
assessing cumulative risk.  Information regarding EPA’s procedures for
cumulating effects from substances found to have a common mechanism can
be found on EPA’s website at   HYPERLINK
"http://www.epa.gov/pesticides/cumulative/"
http://www.epa.gov/pesticides/cumulative/ .

9.0	Occupational Exposure/Risk Pathway  TC \l1 "9.0	Occupational
Exposure/Risk Pathway

	The occupational and residential exposure analyses were explicated in
the Nondietary Exposure/Risk Assessment memorandum for
lambda-cyhalothrin (D334896; Mark I. Dow; 12/26/2006).

9.1	Short- and Intermediate-Term Handler Risk  TC \l2 "9.1
Short-/Intermediate-/Long-Term/Cancer (if needed) Handler Risk

	These products will be applied using groundboom, aerial, or chemigation
equipment.  Based on the use pattern, several major occupational
exposure scenarios were identified for lambda-cyhalothrin:

(1) mixing/loading liquid formulations for aerial application,

(2) mixing/loading liquid formulations for chemigation application,

(3) mixing/loading liquid formulation for groundboom application,

(4) applying spray with aerial equipment,

(5) applying spray with groundboom equipment, and

(6) flagging for aerial spray applications.

The duration of exposure is expected to be short-duration exposure (1-30
days), and intermediate-term duration exposure (1-6 months) for all
scenarios. Long-term exposures (6 months of continuous exposure) are not
expected to occur.

	Inhalation and dermal exposures of occupational handlers were
calculated using data from the Pesticide Handlers Exposure Database
(PHED) Version 1.1, as presented in the  PHED Surrogate Exposure Guide
(August 1998).  Defaults established by the HED’s Science Advisory
Council for Exposure (ExpoSAC) were used for acres treated per day and
body weight.  For pesticide handlers, it is HED’s standard practice to
present estimates of dermal exposure for “baseline”, which 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” plus the use of protective gloves, or
other PPE as might be necessary.  The product labels in this case direct
applicators and other handlers to wear PPE consisting of long-sleeved
shirt, long pants, shoes plus socks, chemical resistant gloves (such as
barrier laminate or viton), and protective eyewear.  Aerial applicators
(pilots) are not required to wear protective gloves or protective
eyewear.

	There are three basic risk mitigation approaches considered appropriate
for controlling occupational exposures.  These include administrative
controls, the use of PPE, and the use of engineering controls.
Occupational handler exposure assessments were completed by HED using
baseline attire, PPE, and engineering controls.  (Note: administrative
controls available generally involve altering application rates for
handler exposure scenarios.  These are typically not utilized for
completing handler exposure assessments.)  The baseline clothing level
scenario for occupational exposure scenarios is generally an individual
wearing long pants, a long-sleeved shirt, no chemical resistant gloves,
and no respirator.  The first level of mitigation generally applied is
PPE.  As reflected in the calculations included herein, PPE may involve
the use of an additional layer of clothing, chemical-resistant gloves,
and a respirator.  The next level of mitigation considered in the risk
assessment process is the use of appropriate engineering controls which,
by design, attempt to eliminate the possibility of human exposure.
Examples of commonly-used engineering controls include enclosed tractor
cabs and cockpits, closed mixing/loading/transfer systems, and
water-soluble packets.

	Since the inhalation and dermal endpoints are based on similar adverse
effects (neurotoxicity and decreased body weight gains), dermal and
inhalation exposures are combined.  See Table 9.1 (below) for a summary
of estimated exposures and risks to occupational pesticide handlers.  An
MOE of 100 or more is adequate to protect occupational pesticide
handlers from exposures to lambda-cyhalothrin.   Provided mixer/loaders
wear personal protective equipment (PPE) as directed by the labels, all
MOEs are greater than 100 (ranging from 110 to 1700), except for
mixer/loaders supporting aerial applications to wild rice at a rate of
0.04 lb ai/A, and 1200 A/day.  Their exposure can be mitigated by
reducing the amount of ai handled per day, or by the use of a dust-mist
respirator (as indicated below in Table 9.1).  Baseline MOEs for
applicators and flaggers range from 820 to 4900.

Table 9.1	Short- and Intermediate-Term Exposure and Risk Assessment For
Lambda-Cyhalothrin Handlers.

Exposure Scenario (Scenario #)	Crop	Dermal Unit Exposure

(mg/lb ai)	Inhalation Unit Exposure

(µg/lb ai)	App. Rate (lb ai/A)	Amount Treated5 (Acres)	Dermal Daily
Dose6 (mg/kg/day)	Inhalation Daily Dose 6 (mg/kg/day)	Dermal MOEs 7

(UF= 100)	Inhalation MOEs 8

(UF = 100)	Total MOE 9

(UF = 100

Baseline 1  (unless indicated)	PPE-G 2	Baseline 3  (unless indicated)
80% R 4

	Baseline 1  (unless indicated)

	PPE-  G 2	Baseline 3  (unless indicated)

	80% R 4	Baseline 1   (unless indicated)	PPE-G 2	Baseline 1 (unless
indicated)	80% R 4	Baseline Dermal + Baseline Inh. (unless indicated)
PPE-G, SL Dermal + Baseline Inh.	PPE-G, SL Dermal + 80% R 4 Inh.

Mixer/Loader Exposure

Mixing/ Loading Liquid Concentrate for Aerial Application (Scenario 1)
Wild rice	2.9	0.023	1.2	0.24	0.04	1,200	2	0.016	0.00082	0.00016	5	630	97
490	4.8	84	280

	Barley, buckwheat, oats, rye	2.9	0.023	1.2	0.24	0.03	1,200	1.5	0.012
0.00062	0.00012	6.7	850	130	NA	6.4	110	NA 10

	Cucurbit vegetables, tuberous and corm vegetables	2.9	0.023	1.2	0.24
0.03	350	0.44	0.0035	0.00018	0.000036	23	2,900	440	NA	22	390	NA

Mixing/ Loading Liquid Concentrate for Chemigation Application (Scenario
2)	Barley, buckwheat, oats, rye, cucurbit vegetables, tuberous and corm
vegetables	2.9	0.023	1.2	0.24	0.03	350	0.44	0.0035	0.00018	0.000036	23
2,900	440	NA	22	390	NA

Mixing/ Loading Liquid Concentrate for Groundboom Application (Scenario
3)	Wild rice	2.9	0.023	1.2	0.24	0.03	200	0.33	0.0026	0.00014	0.000027	30
3,800	580	NA	29	510	NA

	Barley, buckwheat, oats, rye	2.9	0.023	1.2	0.24	0.03	200	0.25	0.002
0.0001	0.000021	40	5,100	780	NA	38	670	NA

Mixing/ Loading Liquid Concentrate for Groundboom Application (Scenario
3)	Cucurbit vegetables, tuberous and corm vegetables	2.9	0.023	1.2	0.24
0.03	80	0.099	0.00079	0.000041	8.2E-06	100	NA	1,900	NA	96	1,700	NA

Applicator Exposure

Applying Sprays via Aerial Equipment

(Scenario 4)	Wild rice	0.005

(eng. control 11)	No Data	0.068

(eng. control)	No Data	0.04	1,200	0.0034 (eng. control)	No Data	0.000047
(eng. control)	No Data	2,900

(eng. control)	No Data	1,700

(eng. control)	No Data	1,100

(eng. control)	NA	NA

	Barley, buckwheat, oats, rye	0.005

(eng. control)	No Data	0.068

(eng. control)	No Data	0.03	1,200	0.0026 (eng. control)	No Data	0.000035
(eng. control)	No Data	3,900

(eng. control)	No Data	2,300

(eng. control)	No Data	1,400

(eng. control)	NA	NA

	Cucurbit vegetables, tuberous and corm vegetables	0.005

(eng. control)	No Data	0.068

(eng. control)	No Data	0.03	350	0.00075 (eng. control)	No Data	0.00001
(eng. control)	No Data	13,000 (eng. control)	No Data	7,800

(eng. control)	No Data	4,900

(eng. control)	NA	NA

Applying Sprays via Groundboom Equipment (Scenario 5)	Wild rice	0.014
0.014	0.74	0.148	0.04	200	0.0016	0.0016	0.000085	0.000017	6,300	NA	950
NA	820	NA	NA

	Barley, buckwheat, oats, rye	0.014	0.014	0.74	0.148	0.03	200	0.0012
0.0012	0.000063	0.000013	8,300	NA	1,300	NA	1,100	NA	NA

	Cucurbit vegetables, tuberous and corm vegetables	0.014	0.014	0.74
0.148	0.03	80	0.00048	0.00048	0.000025	5.1E-06	21,000	NA	3,200	NA	2,700
NA	NA

Flagger Exposure

Flagging for Aerial Spray Applications (Scenario 6)	Wild rice	0.011	No
data	0.35	0.07	0.04	350	0.0022	No data	0.00007	0.000014	4,500	No data
1,100	NA	910	NA	NA

	Barley, buckwheat, oats, rye, cucurbit vegetables, tuberous and corm
vegetables	0.011	No data	0.35	0.07	0.03	350	0.0017	No data	0.000053
0.000011	6,100	No data	1,500	NA	1200	NA	NA

1. Baseline dermal = long-sleeve shirt, long pants, shoes, socks, and no
gloves or respirator (open mixing/loading or open cab or enclosed
cockpit).

2. PPE-G dermal = baseline dermal plus chemical-resistant gloves (open
mixing/loading).