UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

     OFFICE OF	

PREVENTION, PESTICIDES

AND TOXIC SUBSTANCES

Date: 13 August 2009

MEMORANDUM

SUBJECT:	Clothianidin: Human Health Risk Assessment for Proposed Uses on
Berries (Group 13-07H), Brassica Vegetables (Group 5), Cotton, Cucurbit
Vegetables (Group 9), Fig, Fruiting Vegetables (Group 8), Leafy Green
Vegetables (Group 4A), Peach, Pomegranate, Soybean, Tree Nuts (Group
14), and Tuberous and Corm Vegetables (Group 1C).

PC Code:  044309	DP Barcodes:  D355373, D362354

MRID Nos.:  See Below	Registration Nos.:  59639-150, 59639-151,
59639-152

Petition Nos.:  8F7395, 8E7460, 9F7530	Regulatory Action:  Section 3

Assessment Type:  Single Chemical Aggregate	Registration Case No.:  None

TXR No.:  None	CAS No.:  210880-92-5

40 CFR 180.586	Decision Nos.:  397135, 405608



FROM:	Michael A. Doherty, Ph.D., Chemist

		Alan Levy, Ph.D., Toxicologist

		Shih-Chi Wang, Ph.D., Biologist

		Risk Assessment Branch II

		Health Effects Division (7509P)

THROUGH:	Dennis McNeilly, Chemist

		Suku Oonnithan, Biologist

		Linnea Hansen, Ph.D., Toxicologist

		Richard A. Loranger, Ph.D., Senior Scientist

		Christina Swartz, Branch Chief

Risk Assessment Branch II

Health Effects Division (7509P)

TO:		Kable Davis/Venus Eagle (Team 01)

		Insecticide/Rodenticide Branch	

		Registration Division (7505P)

		Barbara Madden

		Risk Integration, Minor Use & Emergency Response Branch

		Registration Division (7505P)

MRID No.	Study Type

47471601	860.1500 Almond

47471602	860.1500 Peppers

47471603	860.1500 Cabbage

47471604	860.1500 Cantaloupe

47471605	860.1500 Cauliflower

47471606	860.1500 Celery

47471607	860.1500/1520 Cotton

47471608	860.1500 Cucumber

47471609	860.1500 Head Lettuce

47471610	860.1500 Leaf Lettuce

47471611	860.1500 Mustard Greens

47471612	860.1500 Pecans

47471613	860.1500/1520 Soybean

47471614	860.1500 Spinach

47471615	860.1500 Summer Squash

47471616	860.1500/1520 Tomato

47578101	860.1500 Peach

47578102	860.1500 Peach

47578103	860.1500 Cranberry

47666901	860.1500 Fig

47666902	860.1500 Pomegranate

46339001	870.5300

46339002	870.5300

46339003	870.5395

46339004	Non-guideline (Unscheduled DNA Synthesis)

47506501	Non-guideline (Rat Developmental Immunotoxicity)



Table of Contents

  TOC \f  1.0	Executive Summary	  PAGEREF _Toc236111513 \h  5 

2.0	Ingredient Profile	  PAGEREF _Toc236111514 \h  7 

2.1	Summary of Registered/Proposed Uses	  PAGEREF _Toc236111515 \h  7 

2.2	Structure and Nomenclature	  PAGEREF _Toc236111516 \h  10 

2.3	Physical and Chemical Properties	  PAGEREF _Toc236111517 \h  11 

3.0	Hazard Characterization/Assessment	  PAGEREF _Toc236111518 \h  11 

3.1	Hazard and Dose-Response Characterization	  PAGEREF _Toc236111519 \h
 11 

3.1.1	Database Summary	  PAGEREF _Toc236111520 \h  11 

3.1.1.1	Studies available and considered (animal, human, general
literature)	  PAGEREF _Toc236111521 \h  11 

3.1.1.2	Mode of action, metabolism, toxicokinetic data	  PAGEREF
_Toc236111522 \h  11 

3.1.1.3	Sufficiency of studies/data	  PAGEREF _Toc236111523 \h  12 

3.1.2	Toxicological Effects	  PAGEREF _Toc236111524 \h  12 

3.1.3	Dose-response	  PAGEREF _Toc236111525 \h  15 

3.1.4	FQPA	  PAGEREF _Toc236111526 \h  15 

3.2	Absorption, Distribution, Metabolism, Excretion (ADME)	  PAGEREF
_Toc236111527 \h  15 

3.3	FQPA Considerations	  PAGEREF _Toc236111528 \h  16 

3.3.1	Adequacy of the Toxicity Database	  PAGEREF _Toc236111529 \h  16 

3.3.2	Evidence of Neurotoxicity	  PAGEREF _Toc236111530 \h  16 

3.3.3	Developmental Toxicity Studies	  PAGEREF _Toc236111531 \h  16 

3.3.4	Reproductive Toxicity Study	  PAGEREF _Toc236111532 \h  17 

3.3.5	Additional Information from Literature Sources	  PAGEREF
_Toc236111533 \h  17 

3.3.6	Pre-and/or Postnatal Toxicity	  PAGEREF _Toc236111534 \h  17 

3.3.6.1	Determination of Susceptibility	  PAGEREF _Toc236111535 \h  17 

3.3.6.2	Degree of Concern Analysis and Residual Uncertainties for Pre-
and/or Postnatal Susceptibility	  PAGEREF _Toc236111536 \h  17 

3.3.7	Recommendation for a Developmental Neurotoxicity Study	  PAGEREF
_Toc236111537 \h  18 

3.3.8	Rationale for the UFDB	  PAGEREF _Toc236111538 \h  18 

3.4	Safety Factor for Infants and Children	  PAGEREF _Toc236111539 \h 
18 

3.5	Hazard Identification and Toxicity Endpoint Selection	  PAGEREF
_Toc236111540 \h  19 

3.5.1	Acute Reference Dose (aRfD) - Females age 13-49	  PAGEREF
_Toc236111541 \h  19 

3.5.2	Acute Reference Dose (aRfD) - General Population	  PAGEREF
_Toc236111542 \h  19 

3.5.3	Chronic Reference Dose (cRfD)	  PAGEREF _Toc236111543 \h  20 

3.5.4	Incidental Oral Exposure (Short- and Intermediate-Term)	  PAGEREF
_Toc236111544 \h  20 

3.5.5	Dermal Absorption	  PAGEREF _Toc236111545 \h  21 

3.5.6	Dermal Exposure (Short-, Intermediate- and Long-Term)	  PAGEREF
_Toc236111546 \h  21 

3.5.7	Inhalation Exposure (Short-, Intermediate- and Long-Term)	 
PAGEREF _Toc236111547 \h  22 

3.5.8	Level of Concern for Margin of Exposure	  PAGEREF _Toc236111548 \h
 22 

3.5.9	Recommendation for Aggregate Exposure Risk Assessments	  PAGEREF
_Toc236111549 \h  22 

3.5.10	Classification of Carcinogenic Potential	  PAGEREF _Toc236111550
\h  22 

3.5.11	Summary of Toxicological Doses and Endpoints for Use in Human
Risk Assessments	  PAGEREF _Toc236111551 \h  23 

3.6	Endocrine disruption	  PAGEREF _Toc236111552 \h  24 

4.0	Public Health and Pesticide Epidemiology Data	  PAGEREF
_Toc236111553 \h  25 

5.0	Dietary Exposure/Risk Characterization	  PAGEREF _Toc236111554 \h 
25 

5.1	Pesticide Metabolism and Environmental Degradation	  PAGEREF
_Toc236111555 \h  25 

5.1.1	Metabolism in Primary Crops	  PAGEREF _Toc236111556 \h  25 

5.1.2	Metabolism in Rotational Crops	  PAGEREF _Toc236111557 \h  26 

5.1.3	Metabolism in Livestock	  PAGEREF _Toc236111558 \h  26 

5.1.3	Metabolism in Livestock	  PAGEREF _Toc236111559 \h  26 

5.1.4	Environmental Degradation	  PAGEREF _Toc236111560 \h  26 

5.1.5	Comparative Metabolic Profile	  PAGEREF _Toc236111561 \h  26 

5.1.6	Toxicity Profile of Major Metabolites and Degradates	  PAGEREF
_Toc236111562 \h  27 

5.1.7	Pesticide Metabolites and Degradates of Concern	  PAGEREF
_Toc236111563 \h  27 

5.1.8	Analytical Methodology	  PAGEREF _Toc236111564 \h  28 

5.1.9	Drinking Water Residue Profile	  PAGEREF _Toc236111565 \h  28 

5.1.10	Food Residue Profile	  PAGEREF _Toc236111566 \h  29 

5.1.11	International Residue Limits	  PAGEREF _Toc236111567 \h  31 

5.2	Dietary Exposure and Risk	  PAGEREF _Toc236111568 \h  33 

6.0	Residential (Non-Occupational) Exposure/Risk Characterization	 
PAGEREF _Toc236111569 \h  34 

7.0	Aggregate Risk Assessments and Risk Characterization	  PAGEREF
_Toc236111570 \h  35 

7.1	Acute Aggregate Risk	  PAGEREF _Toc236111571 \h  35 

7.2	Short- and Intermediate-Term Aggregate Risk	  PAGEREF _Toc236111572
\h  35 

7.3	Long-Term Aggregate Risk	  PAGEREF _Toc236111573 \h  35 

7.4	Cancer Risk	  PAGEREF _Toc236111574 \h  35 

8.0	Cumulative Risk Characterization/Assessment	  PAGEREF _Toc236111575
\h  35 

9.0	Occupational Exposure/Risk Pathway	  PAGEREF _Toc236111576 \h  36 

9.1	Short- and Intermediate-Term Handler Risk	  PAGEREF _Toc236111577 \h
 36 

9.2	Short- and Intermediate-Term Post-Application Risk	  PAGEREF
_Toc236111578 \h  40 

10.0	Data Needs and Label Recommendations	  PAGEREF _Toc236111579 \h  41


10.1	Toxicology	  PAGEREF _Toc236111580 \h  41 

10.2	Residue Chemistry	  PAGEREF _Toc236111581 \h  41 

10.3	Occupational and Residential Exposure	  PAGEREF _Toc236111582 \h 
42 

References:	  PAGEREF _Toc236111583 \h  44 

Appendix A:	Toxicology Assessment	  PAGEREF _Toc236111584 \h  45 

A1.	Toxicology Data Requirements	  PAGEREF _Toc236111585 \h  45 

A2.	Toxicity Profiles	  PAGEREF _Toc236111586 \h  46 

A3.	Toxicology Executive Summaries	  PAGEREF _Toc236111587 \h  55 

 1.0	Executive Summary  TC \l1 "1.0	Executive Summary 

Clothianidin,
(E)-N-[(2-Chloro-5-thiazolyl)methyl]-N’-methyl-N”-nitroguanidine, is
a broad spectrum, systemic neonicotinoid insecticide (Group 4A
insecticide) and is identical to the major metabolite (CGA-322704) of
the active ingredient thiamethoxam.  Permanent tolerances are
established for residues of clothianidin in/on various plant and
livestock commodities [40 CFR §180.586].  Valent has submitted
petitions (PP#s 8F7395 and 9F7530) proposing new uses for clothianidin
formulated as a 50% water-dispersible granule (WDG; Arena® 50 WDG, EPA
Reg. No. 59639-152) and a 2.13 lb/gal flowable concentrate (FlC; V-1070
2.13 SC, EPA Reg. No 59639-150) for the control of various insects on
the following crops/crop groups:  Brassica leafy vegetables, cotton,
cucurbit vegetables, figs, fruiting vegetables, leafy vegetables,
pomegranates, soybeans and tree nuts.  In addition, Interregional
Research Project No. 4 (IR-4) has submitted a separate petition
(PP#8E7460) proposing new uses for Valent’s 50% WDG and 2.13 lb/gal
FlC formulations on peaches and members of the low-growing berry (except
strawberry) Subgroup 13-07H.  HED has sufficient information to complete
a human health risk assessment for these requested uses.

The toxicological database for clothianidin is complete.  The available
data indicate that there are no consistent specific target organs in
mammals.  The majority of studies show decreases in body weights and
body weight gains.  More severe developmental (missing lobe of the lung
in the rabbit) and neurological effects in rats and mice are
attributable to exposure to clothianidin; these effects serve as the
basis for acute risk assessments.  Effects on body weight gain, delayed
sexual maturation, decreased thymus weights, and an increase in
stillbirths are the basis for assessing short-, intermediate-, and/or
long-term (chronic) exposures.  Based on the completeness of the
database, the observed effects, and the endpoints used for risk
assessment, the FQPA Safety Factor has been reduced to 1X, leaving the
100X safety factor to account for within-species (10X) and
across-species (10X) variability.  Clothianidin has been classified as
not likely to be carcinogenic to humans.

The submitted residue chemistry data are relatively complete;
nevertheless, more data are needed in order to recommend for the full
suite of requested uses.  In spite of the lack of certain data, HED is
recommending for the establishment of permanent tolerances for all of
the requested crops; however, label revisions are needed prior to
registration and HED is requesting residue data comparing soil and
foliar applications as a condition of registration.  Bridging studies
examining the effects of adjuvants and different formulations are also
being requested.  Suitable analytical methods are available to enforce
tolerances for residues of clothianidin.  

No chemical-specific data for assessing human exposures during pesticide
handling or post-application activities were submitted to the Agency in
support of the requested registrations of clothianidin.  HED used
surrogate data from the Pesticide Handler’s Exposure Database (PHED),
in combination with HED-standard assumptions to assess exposures for
crop protection uses.  

The available data are adequate for assessment of exposure to
clothianidin, and HED has evaluated dietary, non-dietary (i.e.,
residential/recreational), and occupational risks associated with the
registered and requested uses of thiamethoxam.  For the dietary pathway,
thiamethoxam has been included as a source of exposure to clothianidin. 
All of the dietary, non-dietary, and occupational exposure estimates are
based on conservative, health-protective assumptions.  The exposure
estimates, especially when combined to take into account aggregate
(dietary + non-dietary) exposure, may over-estimate actual exposures
that are likely to occur.  Despite this, all risk estimates for
clothianidin, including aggregate risk estimates, for all population
groups are below HED’s level of concern.  There are no human health
risk issues that preclude establishing tolerances and granting the
requested registrations for clothianidin for which sufficient data have
been submitted (see below).

Summary of Requested Uses Supported by Available Data for Clothianidin

Requested Use	Supported by Available Data

	Application	Formulation	Tank Mix

Adjuvant

	Foliar	Soil	WDG	FlC

	Berries (Group 13-07H)	Yes	No	Yes	No	No

Brassica Vegetables (Group 5)	Yes	No	Yes	No	No

Cotton	Yes	No	Yes	No	No

Cucurbit Vegetables (Group 9)	Yes	No	Yes	No	No

Fruiting Vegetables (Group 8)	Yes	No	Yes	No	No

Leafy Green Vegetables (Group 4A)	Yes	No	Yes	No	No

Peach	Yes	No	Yes	No	No

Soybean	Yes	No	Yes	No	Yes

Tree Nuts (Group 14)	Yes	No	Yes	No	Yes (except almond)

Tuberous and Corm Vegetables (Group 1C)	Yes	No	Yes	No	No

Fig	Yes	No	No	Yes	Yes

Pomegranate	Yes	No	No	Yes	Yes

Soybean	Seed Treatment	Yes	Yes	Not Applicable

Potato Seed Pieces	Seed Treatment	Yes	Yes	Not Applicable



Human Studies.  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, which comprise the Pesticide Handlers
Exposure Database (PHED) & Agricultural Re-Entry Task Force (ARTF), have
been determined to require a review of their ethical conduct, and have
received that review. The studies in PHED and ARTF were considered
appropriate (or ethically conducted) for use in risk assessments.

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

As a part of every pesticide risk assessment, OPP considers a large
variety of consumer subgroups according to well-established procedures. 
In line with OPP policy, HED estimates risks to population subgroups
from pesticide exposures that are based on patterns of that subgroup’s
food and water consumption, and activities in and around the home that
involve pesticide use in a residential setting.  Extensive data on food
consumption patterns are compiled by the USDA under the Continuing
Survey of Food Intake by Individuals (CSFII) and are used in pesticide
risk assessments for all registered food uses of a pesticide.  These
data are analyzed and categorized by subgroups based on age, season of
the year, ethnic group, and region of the country.  Additionally, OPP is
able to assess dietary exposure to smaller, specialized subgroups and
exposure assessments are performed when conditions or circumstances
warrant.  Whenever appropriate, non-dietary exposures based on home use
of pesticide products and associated risks for adult applicators and for
toddlers, youths, and adults entering or playing on treated areas
postapplication 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.

Provided the label revisions and revised Section F detailed in Section
10.2 are submitted, HED recommends for the requested soybean and potato
seed treatments, for foliar uses as detailed in the preceding table, and
for the tolerances detailed in Table 10.

2.0	Ingredient Profile  TC \l1 "2.0	Ingredient Profile 

Clothianidin is a broad spectrum, systemic insecticide belonging to both
the chloronicotinyl (neonicotinoid) and nitroguanidine classes of
chemicals.  It is also a major metabolite of thiamethoxam.  Clothianidin
acts by binding with the nicotinic acetylcholine receptor sites in
insects (Group 4A insecticide), interfering with neural transmission of
stimuli and eventually inhibiting reproduction of the insect. 
Clothianidin Technical Insecticide was first registered in the U.S.
during 2003 by Takeda, with Bayer CropScience (Bayer) acting as their
Agent.  Bayer currently has six end-use products containing clothianidin
that are registered only for seed treatment uses on corn, canola,
cotton, rapeseed, and sorghum.  Clothianidin end-use products with
direct foliar and/or soil uses on grapes, pome fruits, potatoes and
tobacco were originally registered to Arvesta (now known as Arysta). 
However, these products/uses have been transferred to Valent, which is
now the Agent for Sumitomo Chemical Co. which owns the current
registration for Technical Clothianidin.  The chemical structure and
nomenclature of clothianidin and its metabolite, TMG, are listed in
Table 2.2, and the physicochemical properties of technical grade
clothianidin are listed in Table 2.3.

2.1	Summary of Registered/Proposed Uses  TC \l2 "2.1	Summary of
Registered/Proposed Uses 

Permanent tolerances are established for residues of clothianidin in/on
a variety of plant commodities at levels ranging from 0.01 ppm in/on a
number of crops to 1.0 ppm in/on pome fruits [40 CFR §180.586(a)]. 
Tolerances for clothianidin have also been established in milk at 0.01
ppm.  Time-limited tolerances have been established at 0.02 ppm in/on
sugar beet roots and tops [40 CFR §180.586(b)]; these tolerances are
set to expire on 12/31/09.  In addition, tolerances for indirect or
inadvertent residues have been established for clothianidin at 0.02 ppm
in/on non-grass animal feeds, the forage, fodder and straw of cereal
grains, grass forage, fodder and hay, and soybean forage and hay [40 CFR
§180.586(d)].

Valent has submitted petitions (PP#s 8F7395 and 9F7530) proposing new
uses for its 50% WDG and 2.13 lb/gal FlC formulations on Brassica leafy
vegetables, cotton, cucurbit vegetables, figs, fruiting vegetables,
leafy vegetables, pomegranates, soybeans and tree nuts.  Valent is also
proposing to amend the use directions for its 5 lb/gal FlC formulation
to include a seed treatment use on potato seed pieces and soybean seeds.
 In addition, IR-4 has submitted a separate petition (PP#8E7460)
proposing new uses for Valent’s 50% WDG and 2.13 lb/gal FlC
formulations on peaches and members of the low-growing berries subgroup,
except strawberry (Subgroup 13-07H).  IR-4 is also proposing that the
current use directions for potatoes on the labels for the 50% WDG and
2.13 lb/gal FlC be amended to cover all tuberous and corm vegetables
(Subgroup 1C).  The use patterns associated with the requested uses are
summarized in Table 2.1.

Table 2.1.	Summary of Proposed Directions for Use of Clothianidin.

Applic. Timing, Type, and Equip.1	Formulation

[EPA Reg. No.]	Applic. Rate 

(lb ai/A)	Max. No. Applic. per Season	Max. Seasonal Applic. Rate

(lb ai/A)	PHI

(days)	Use Directions and Limitations 2

Brassica Vegetables, Leafy Vegetables, Cucurbit Vegetables, and Fruiting
Vegetables

Soil application at planting or post-planting 3; ground equipment	50%
WDG [59639-152] 2.13 lb/gal FlC

[59639-150]	0.2	1	0.2	7	The minimum RTI for foliar applications is 10
days.

A minimum application volume is not specified.

Broadcast foliar applications as pest populations begin to build; ground
equipment 

0.05-0.067	NS	0.2	7

	Cotton

Broadcast foliar applications as pest populations reach threshold
levels; ground equipment 	50% WDG [59639-152] 2.13 lbs/gal FlC

[59639-150]	0.05-0.067	NS	0.2	21	The minimum RTI is 7 days.

A minimum application volume is not specified.

Low Growing Berries, except Strawberry (Subgroup 13-07H)

Single post-bloom soil application as pest populations reach threshold
levels; ground equipment	50% WDG [59639-152] 2.13 lbs/gal FlC

[59639-150]	0.2	1	0.2	21	The minimum RTI is 7 days for foliar
applications.

A minimum application volume is not specified.

Post-bloom broadcast foliar applications as pest populations reach
threshold levels; ground equipment

0.066	NS

21

	Fig

Post-bloom broadcast foliar applications as pest populations reach
threshold levels; ground equipment 	50% WDG [59639-152] 2.13 lbs/gal FlC

[59639-150]	0.06-0.09	2	0.2	7	The minimum RTI is 14 days.

Apply in a minimum of 100 gal/A.

Do not allow livestock to graze on cover crops from treated orchards.

Pomegranate

Post-bloom broadcast foliar applications as pest populations reach
threshold levels; ground equipment 	50% WDG [59639-152] 2.13 lbs/gal FlC

[59639-150]	0.06-0.09	2	0.2	7	The minimum RTI is 14 days.

Apply in a minimum of 100 gal/A.

Do not allow livestock to graze on cover crops from treated orchards.

Peach

Post-bloom broadcast foliar applications as pest populations reach
threshold levels; ground equipment 	50% WDG [59639-152] 2.13 lbs/gal FlC

[59639-150]	0.05-0.1	NS	0.2	7	The minimum RTI is 10 days.

A minimum application volume is not specified.

Do not allow livestock to graze on cover crops from treated orchards.

Potato/ Tuber and Corm Vegetables, Subgroup 1C 4

Seed-piece treatment; spray	5 lb/gal FlC

[59639-151]

2.13 lb/gal FlC

[59639-150]	0.01 lb ai/ 100 lb seed pieces

(0.2 lb ai/A) 5	1	0.2	NA	Do not use treated seed pieces for food, feed,
or fodder.  

Do not apply any subsequent application of clothianidin following seed
piece treatment.

In-furrow soil application at planting, or side-dress or broadcast soil
application at ground-crack during hilling; ground equipment	50% WDG
[59639-152] 2.13 lbs/gal FlC

[59639-150]	0.12-0.19	1	0.2	NA	The minimum RTI for foliar applications
is 7 days.

A minimum application volume is not specified.



Broadcast foliar applications as pest populations reach threshold
levels; ground equipment 

0.03-0.05	3	0.2	14

	Soybean

Seed Treatment, commercial seed treatment equipment	5 lb/gal FlC

[59639-151]	0.05 lb ai/

100 lb seed

(0.05 lb ai/A) 6	1	0.05	NA	Do not use treated seed for feed, food or oil
processing.

Broadcast foliar applications as pest populations reach threshold
levels; ground equipment 	50% WDG [59639-152] 2.13 lb/gal FlC

[59639-150]	0.05-0.067	NS	0.2	21	The minimum RTI for foliar applications
is 7 days.

A minimum application volume is not specified.

Do not apply foliar applications following a seed treatment with
clothianidin

Tree Nuts

Broadcast foliar or chemigation applications at post bloom; ground
equipment 	50% WDG [59639-152] 2.13 lb/gal FlC

[59639-150]	0.05-0.10	NS	0.2	21	The minimum RTI is 10 days.

A minimum application volume is not specified.

Do not allow livestock to graze on cover crops from treated orchards.

1	Do not apply by air.  Applications are allowed through the following
types of irrigations systems:  micro (spaghetti tubes), drip, and
overhead sprinklers (center pivot, solid set, hand move or moving wheel
systems).  Do not apply through any irrigation system connected to the
public water system.  Applications may include use of a spray adjuvant. 

2	A 12-hour restricted entry interval is specified.  Do not apply to
vegetable, fruit or tree nut crops during pre-bloom, bloom or when bees
are actively foraging.   For all crops, do not apply a foliar
application of clothianidin following a soil application; and do not
apply more than 0.2 lb ai/A of clothianidin per season.

3	Soil applications can be made as either a narrow band centered on the
plant row, an in-furrow spray at planting on or below the seed, a
side-dress application to both sides of the row, a post-seeding drench
or transplant water drench, or by chemigation into the root zone through
drip, trickle, or micro-sprinkler systems.

4	The uses of the 50% WDG and 2.13 lb/gal FlC formulations on potatoes
were previously approved under PP#4F6869 (DP# D303164, W. Drew, 2/1/06).

5	The use rate per acre for the potato seed piece treatment is based on
a planting rate of 2,000 lb of seed pieces/acre.

6	The worst-case use rate per acre for the soybean seed treatment
assumes a high planting density (200,000 plants/A) and use of larger
seeds (2,000 seed/lb), which would require 100 lb of seed/A.  A more
typical planting density of 160,000 seed/A using average sized seed
(3,000 seed/lb) would result in a use rate of 0.026 lb ai/A.

NA = Not applicable.

NS = not specified.

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

The chemical structure and nomenclature of clothianidin and its TMG
metabolite are summarized in Table 2.2.  Physical/chemical properties
for clothianidin are summarized in Table 2.3.  Based on the available
data, clothianidin has a very low vapor pressure and exposure to this
chemical in the vapor phase is not expected.  The octanol/water
partitioning coefficient is also quite low, indicating that clothianidin
is unlikely to accumulate in fatty tissues.

Table 2.2.	Clothianidin Nomenclature.

Parent Compound	

Common name	Clothianidin

Company experimental name	TI-435, V-10066

IUPAC name
(E)-1-(2-Chloro-1,3-thiazol-5-ylmethyl)-3-methyl-2-nitroguanidine

CAS name
(E)-N-[(2-Chloro-5-thiazolyl)methyl]-N’-methyl-N”-nitroguanidine

CAS registry number	210880-92-5 (formerly 205510-53-8)

Molecular wt.	249.68

End-use product (EP)	50% WDG (Arena® 50 WDG; EPA Reg. No. 59639-152)

2.13 lb/gal FlC (V-10170 2.13 SC; EPA Reg. No. 59639-150)

5 lb/gal FlC (V-10170 5 FS; EPA Reg. No. 59639-151)

Metabolite	

Common name	Thiazolylmethylguanidine

Company experimental name	TMG

IUPAC name	N-(2-chlorothiazol-5-yl)-N´-methylguanidine

CAS Name	N-(2-chlorothiazol-5-yl)-N´-methylguanidine

CAS registry number	635283-91-9

Molecular wt.	204.68



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

Table 2.3.	Physicochemical Properties of Clothianidin.

Parameter	Value	Reference

Melting point (ºC)	176.8	D335355, W. Drew, 10/16/07

pH at 23ºC	6.24 (1% solution/suspension)

	Density (g/cm3)	1.61 (PAI)*, 1.59 (TGAI)

	Water solubility (g/L at 20ºC)	0.327

	Solvent solubility (g/L at 25ºC)	Acetone	15.2	Dichloromethane	1.32

Ethyl acetate	2.03	Heptane 	<0.00104

Methanol	6.26	Octanol	0.938

Xylene	0.0128

	Vapor pressure (Pa at 20ºC)	1.3 x 10 -10

	Dissociation constant, pKa at 20ºC	11.09

	Octanol/water partition coefficient, Log(KOW) at 25ºC	0.7

	UV/visible absorption spectrum (Maximum, nm)	265.5 (acidic or neutral)

246.0 (basic)

	*PAI = Purified Active Ingredient; TGAI = technical grade active
ingredient.

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

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

3.1.1	Database Summary  TC \l3 "3.1.1	Database Summary 

The toxicological database for clothianidin is complete.  The scientific
quality is relatively high and the toxicity profile of clothianidin can
be characterized for most effects, including potential carcinogenic,
mutagenic, developmental and reproductive, neurotoxic and immunotoxic
effects.  Since the last risk assessment for clothianidin, the Agency
has received and reviewed a developmental immunotoxicity study and four
mutagenicity studies (see Appendix A3).

3.1.1.1	Studies available and considered (animal, human, general
literature)  TC \l4 "3.1.1.1	Studies available and considered (animal,
human, general literature) 

The following studies were submitted: acute and subchronic
neurotoxicity; subchronic in rats, mice and dogs; subchronic dermal,
chronic/carcinogenicity in rats; carcinogenicity in mice; chronic in
dogs; developmental in rats and rabbits; developmental neurotoxicity;
reproduction; mutagenicity battery; metabolism (rats and mice); dermal
penetration (monkeys) and immunotoxicity as well as developmental
immunotoxicity.

3.1.1.2	Mode of action, metabolism, toxicokinetic data  TC \l4 "3.1.1.2
Mode of action, metabolism, toxicokinetic data 

Clothianidin is a major metabolite of the active ingredient thiamethoxam
and is a systemic insecticide that belongs to the nitroguanidine
sub-class of neonicotinoid compounds, which have agonistic activity on
nicotinergic acetylcholine receptors (nAChR).  It enters through the
roots and cotyledons of newly germinating seedlings and protects below-
and above-ground plant parts from insect damage.  

In rats, clothianidin was readily absorbed and excreted within 96 hours
following a single or repeated low doses, but at a high dose, absorption
became biphasic and was saturated.  The studies suggest that a multiple
exposure regimen did not affect the absorption/excretion processes. 
There was rapid absorption and distribution of administered
radioactivity to all organs and tissues followed by rapid excretion
primarily via the urine (>89% of dose) and to a lesser extent, the
feces, with reduction to background levels in most tissues and organs
within 24 hours.  There was a somewhat greater rate of absorption and
elimination in females.  Excretory patterns did not exhibit
gender-related variability but reflected the delayed absorption in the
high-dose group.  The metabolites identified (primarily oxidative
demethylation products and cleavage products of the nitrogen-carbon bond
between the nitroimino and thiazolyl moieties) were consistent with
Phase I processes of oxidation, reduction and hydrolysis.

 

In mice, clothianidin was readily absorbed and excreted within 168 hours
following a single low dose.  Urine was the major route of excretion. 
Neither clothianidin nor its metabolites appeared to exhibit potential
for bioaccumulation.  Excretory patterns did not exhibit gender-related
variability.  The major metabolites in both urine and feces were the
parent compound (clothianidin) and TZNG
[N-(2-chlorothiazol-5-ylmethyl)-N’-nitroguanidine], which resulted
from N-demethylation of clothianidin.

3.1.1.3	Sufficiency of studies/data  TC \l4 "3.1.1.3	Sufficiency of
studies/data 

Data are sufficient for FQPA evaluation, toxicity endpoint selection and
dose-response evaluation.  

3.1.2	Toxicological Effects  TC \l3 "3.1.2	Toxicological Effects 

Clothianidin and its metabolites have relatively low (Category III or
IV) acute toxicity via oral, inhalation and dermal routes of exposure in
the rat and there is no evidence of dermal sensitization or eye
irritation with the exception of the clothianidin-triazan intermediate,
which is a dermal sensitizer.  The other exceptions were for technical
clothianidin and the TMG metabolite via the oral route in the rat both
of which were toxicity Category II.

Clothianidin induces some effects that are similar to other
neonicotinoid insecticides, particularly on the liver, hematopoietic
system and kidneys.

Acute neurotoxicity studies were conducted in rats and mice following
exposure by gavage.  Comparing these two studies, mice appear to be more
sensitive than rats.  In the acute neurotoxicity rat study, FOB effects,
including decreased arousal as well as decreased motor and locomotor
activity, were seen at the LOAEL on Day 0 in males.  Effects at dose
levels above the LOAEL in the rat study included tremors, slightly
uncoordinated gait, effects on pupil response and righting reflex, and
decreases in both temperature and ataxia.  In the acute neurotoxicity
study in mice, effects were also observed on Day 0 in males (no female
mice were tested), but they occurred at lower doses than those that
produced neurotoxic effects in rats.  Effects seen at the LOAEL in this
mouse study included transient signs of decreased spontaneous motor
activity, tremors and deep respirations.  At higher dose levels, the
following were observed: decreases in reactivity, grooming and muscle
tone; prone position; staggering gait; mydriasis; and hypothermia.

In rats only, a subchronic neurotoxicity study was conducted following
dietary exposure.  In contrast to the acute neurotoxicity study
described previously, no indications of neurotoxicity were noted in the
subchronic study.  Slightly decreased food consumption, body weights and
body weight gains were the only observed effects.

In subchronic oral studies in rats and dogs, decreases in body weight
and body weight gain were observed.  In addition, dogs also displayed
decreased white blood cells, albumin and total protein, as well as some
anemia, and they appeared to be more sensitive than rats.  Male dogs
were more sensitive than females.  No effects were observed up to the
limit dose in the 28-day dermal study in rats.

Chronic feeding studies were conducted in the dog, rat and mouse. 
Anemia was observed in the dog.  In the rat, decreased body weight and
food consumption, interstitial gland hyperplasia in the ovary, increased
lymphohistiocytic infiltrate and altered hepatocellular eosinophilic
foci of the liver were observed in females; decreased body weight and
food consumption, slightly increased incidences of pelvic
mineralization, and transitional cell hyperplasia in the kidney, mottled
livers, and altered hepatocellular eosinophilic foci in the liver were
observed in male rats.  In the mouse, decreases in body weight and body
weight gain in females and increases in vocalization in both sexes were
the only observed effects.  Anemia, only in females, was observed at the
highest dose tested in dogs.

A comparison of the subchronic and chronic feeding studies in rats
showed that a wider spectrum of effects was observed in the chronic
study, even though the NOAELs and LOAELs in these two studies were
similar.  Thus, it appears that there may be more toxicity in rats when
exposure is over a longer period of time.  In contrast, administration
to the dog for a longer period of time does not appear to result in any
additional effects or effects at lower doses.

There was an increase in quantitative susceptibility in the
developmental neurotoxicity study.  Effects in the offspring were
observed at a lower dose than the dose which caused toxicity in the
maternal animals.  However, this increased susceptibility does not
require an additional 10X uncertainty factor because endpoints selected
for assessment of risks to infants and children are at doses below the
offspring NOAEL observed in this study and thus are protective of these
effects.  Maternal effects included decreased body weights, body weight
gains and food consumption.  Effects seen in the offspring included
decreased body weights, body weight gains, motor activity and acoustic
startle response in females.

No increased quantitative or qualitative susceptibility was observed in
the developmental rat or rabbit studies.  In the rat, no developmental
toxicity was observed at the highest dose tested, although this dose
induced decreases in body weight gain and food consumption in the dams. 
In the rabbit, premature deliveries, decreased gravid uterine weights,
an increase in litter incidence of a missing lobe of the lung and a
decrease in the litter average for ossified sternal centra per fetus
were noted at a dose level at which maternal death, a decrease in food
consumption and clinical signs (scant feces and orange urine) were
observed.  The developmental effects in this study are not considered to
be quantitatively more severe than the maternal effects because they
occurred at the same dose and they are not considered to be
qualitatively more severe because death occurred in the dams.

Increased quantitative susceptibility was observed in the two-generation
reproduction study since the offspring NOAEL was lower than the parental
NOAEL.  The LOAEL for offspring toxicity is based on decreased body
weight gains, delayed sexual maturation (males), decreased absolute
thymus weights in F1 pups of both sexes, and an increase in stillbirths
in both generations.  The parental systemic LOAEL is based on decreased
absolute body weights and body weight gains with decreased absolute and
relative thymus weights in both sexes.

In the rat chronic carcinogenicity study, an apparent increase in
thyroid c-cell tumors was observed in females.  A statistical analysis
revealed that the increase in these tumors did not appear to be
significant, especially when carcinomas and adenomas were combined.  An
increased incidence of hepatocellular carcinomas at the low and high
doses were just outside historical control incidences for the same
testing laboratory (only 2 studies) but were within the historical
control range for the animal supplier.  In addition, there was no
dose-response.  Also, there was no continuum (i.e., no preneoplastic
lesions and no adenomas).  There was no evidence of an increase of
tumors in mice.  Therefore, clothianidin is classified as not likely to
be carcinogenic to humans.

 

In the mutagenicity studies, none of the intermediates or metabolites
appeared to have genotoxic potential under the conditions of the
studies, but the studies for the technical material gave mixed results. 
Some of the batches of test material were positive and some were
negative.  HED had requested that the composition of the test materials
used in the mutagenicity studies be investigated to determine whether or
not the differences in composition may have affected the results from
the studies.  To address the request, additional mutagenicity studies
were performed and it was determined that there was no concern because
clothianidin was neither clastogenic nor aneugenic in the mouse bone
marrow micronucleus assay up to a toxic oral dose (100 mg/kg); also,
there was no induction of unscheduled DNA synthesis (UDS) in the livers
of Wistar male mice when administered at the limit dose of 2000 mg/kg.

In some of the toxicity studies, there was evidence of possible effects
on the immune system.  Decreased absolute and relative thymus and spleen
weights were observed in multiple studies.  In addition, juvenile rats
in the two-generation reproduction study appeared to be more susceptible
to these effects.  The thymus is involved in the production of T cells,
whose function is to recognize and respond to foreign antigens.  The
spleen serves an important function in clearing the blood of infectious
organisms.  A guideline immunotoxicity study showed no evidence of
clothianidin-mediated immunotoxicity in adult rats, in the form of a
T-cell dependent anti-Sheep Red Blood Cell (SRBC) forming cell response,
at doses lower than those resulting in generalized signs of toxicity
(e.g., decreases in body weight).  However, since effect in the
offspring occurred at lower doses in the two-generation study, HED
concluded that the lack of effects on immunotoxicity in adults did not
alleviate concerns for immunotoxicity in the offspring.  A developmental
immunotoxicity study was required and demonstrated no susceptibility
with respect to immunotoxicity.

In a dermal absorption study in monkeys, absorption was calculated as
0.24% (±0.11%).  This value was determined by adding the radioactivity
recovered from urinary excretion, fecal excretion and from
cage/pan/chair wash debris.  Adjustment of the direct absorption
determination was not necessary because recovery from the dermal dose
was >90%.  A value of 1% dermal absorption has been recommended as
appropriate for use in risk assessment.  This estimation takes into
account any variability that would have likely occurred with testing
several dose levels.  The mouse single dose and rat single and multiple
dose metabolism studies indicated that oral absorption was in the range
of 90% or greater.  Therefore, any extrapolation from the oral to the
dermal route using the dermal absorption factor is not likely to
underestimate anticipated adverse effects.

3.1.3	Dose-response  TC \l3 "3.1.3	Dose-response 

The database on clothianidin indicates no consistent specific target
organs at the doses tested.

Decreases in body weights and body weight gains were consistently
observed among species and at different dosing durations.  Clinical
signs of neurotoxicity were exhibited in both rats and mice in the
single dose (gavage) studies; however, no indications of neurotoxicity
were observed in the subchronic (dietary) rat study.  In a developmental
neurotoxicity study in rats, decreased body weights, body weight gains,
motor activity and acoustic startle response amplitude (females) were
seen in offspring at doses lower than those resulting in maternal
toxicity.  Although the NOAELs were similar for the subchronic and
chronic feeding studies in the rat, a greater spectrum of effects was
observed in the chronic study.  Dogs dosed for 3 months or 1 year
exhibited clinical signs of anemia.   The only observed effects in mice
following chronic dietary administration were increases in vocalization
and decreases in body weight and body weight gains.  There was no
evidence of increased quantitative or qualitative susceptibility of rat
or rabbit fetuses in developmental studies; however, increased
quantitative susceptibility of rat pups was seen in both the
reproduction and developmental neurotoxicity studies.  The degree of
concern for both of these studies is low because the observed effects
are well characterized and there are clear NOAELs.  

3.1.4	FQPA  TC \l3 "3.1.4	FQPA 

See Sections 3.3 and 3.4.

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

In rats, clothianidin was readily absorbed and excreted within 96 hours.
 Females showed a greater rate of absorption.  Metabolites were
primarily oxidative demethylation and cleavage products.

In mice, absorption and excretion were complete within 168 hours with
urine as the major excretory route.  No bioaccumulation was apparent. 
Parent and TZNG metabolite were noted in urine and feces.  

A dermal absorption study in the monkey indicated that absorption was
0.24%.

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 

The database for evaluating in utero or postnatal susceptibility is
adequate for evaluation of the FQPA safety factor.  The following
acceptable studies are available:

	Developmental toxicity studies in rats and rabbits

	Two-generation reproduction study in rats

	Developmental neurotoxicity study in rats

	Developmental immunotoxicity study in rats

3.3.2	Evidence of Neurotoxicity  TC \l3 "3.3.2	Evidence of Neurotoxicity


Clothianidin was tested in the following three rat neurotoxicity
studies: acute, 90-day and developmental.  In addition, a
neurotoxicity/pharmacology single dose study was performed in mice. 

In the acute neurotoxicity study, decreased arousal, motor activity and
locomotor activity were observed; however, in the subchronic study, the
LOAEL was based on decreased body weights, body weight gains and food
consumption with no evidence of neurotoxicity.

In the developmental neurotoxicity study, the maternal effects included
decreased body weights, body weight gains and food consumption; whereas,
in the offspring, decreased body weights, body weight gains, motor
activity and acoustic startle response in females were observed at a
lower dose than the dose required to induce effects in the dams.

In the single dose mouse study, transient signs of decreased spontaneous
motor activity, tremors and deep respirations were observed.

No signs of neurotoxicity were observed in the remainder of the toxicity
studies.

3.3.3	Developmental Toxicity Studies  TC \l3 "3.3.3	Developmental
Toxicity Studies 

In the gavage developmental studies, there is no evidence of increased
quantitative or qualitative susceptibility of rat or rabbit fetuses to
in utero exposure to clothianidin.  The developmental NOAELs are either
higher than or equal to the maternal NOAELs.  The toxicological effects
in fetuses are not considered to be more severe than those in the dams
or does.

In the rat developmental neurotoxicity study, there was evidence of
increased quantitative susceptibility, because offspring effects were
observed at lower doses than doses at which maternal effects were
observed; however, the effects were not considered to be more severe. 
The maternal NOAEL was 43 mg/kg/day with the LOAEL being 142 mg/kg/day
based on decreased body weight, body weight gain and food consumption. 
For offspring, the NOAEL was 13 mg/kg/day and the LOAEL was 43 mg/kg/day
based on decreases in body weights, body weight gains, motor activity
and acoustic startle response in females.  Nonetheless, HED considers
the degree of concern for the developmental neurotoxicity study to be
low and there are no residual uncertainties for pre- and/or postnatal
toxicity because the observed effects are well characterized and there
are clear NOAELs/LOAELs.

3.3.4	Reproductive Toxicity Study  TC \l3 "3.3.4	Reproductive Toxicity
Study 

Increased quantitative susceptibility was observed in the two-generation
reproduction study, in which offspring toxicity (decreased body weight
gains, delayed sexual maturation in males, decreased absolute thymus
weights in F1 pups of both sexes and an increase in stillbirths in both
generations) was seen at a dose lower than that which caused parental
toxicity consisting of decreased body weight gains as well as decreased
thymus weights (absolute and relative).

3.3.5	Additional Information from Literature Sources  TC \l3 "3.3.5
Additional Information from Literature Sources 

None.

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

3.3.6.1	Determination of Susceptibility  TC \l4 "3.3.6.1	Determination
of Susceptibility 

While no increased quantitative or qualitative susceptibility was
observed in either of the developmental rat or rabbit studies, increased
quantitative susceptibility was observed in both the developmental
neurotoxicity and rat reproduction studies.  In the developmental
neurotoxicity study, offspring toxicity (decreased body weight gains,
motor activity and acoustic startle response) was seen at a lower dose
than the dose what caused maternal toxicity.  However, HED determined
that the degree of concern for the developmental neurotoxicity study is
low and there are no residual uncertainties for pre- and/or postnatal
toxicity because the observed effects are well characterized and there
are clear NOAELs/LOAELs.

In the two-generation reproduction study, offspring toxicity (decreased
body weight gains, delayed sexual maturation in males, decreased
absolute thymus weights in F1 pups of both sexes and an increase in
stillbirths in both generations) was seen at a dose lower than that
which caused parental toxicity.

Immunotoxicity and developmental immunotoxicity studies were performed
and neither showed any changes in the immune system parameters examined.

3.3.6.2	Degree of Concern Analysis and Residual Uncertainties for Pre-
and/or Postnatal Susceptibility  TC \l4 "3.3.6.2	Degree of Concern
Analysis and Residual Uncertainties for Pre- and/or Postnatal
Susceptibility  

There is low concern for an increase in quantitative or qualitative
susceptibility in rats or rabbits in the developmental studies.  In the
rat study, no developmental effects were noted in the highest dose
tested; whereas, there was a decrease in maternal body weights and body
weight gains as well as food consumption.  In the rabbit developmental
study, maternal death occurred as the same dose as the fetal findings. 
In the rat developmental neurotoxicity study, although there were
neurotoxic signs in the offspring (decreased motor activity and acoustic
startle response in females) at a dose lower than the maternal effects,
the degree of these findings was considered to be minor and there would
be little or no concern because the doses selected for risk assessment
are protective of the effects observed in the developmental
neurotoxicity study.

In the two-generation reproduction study, the offspring NOAEL (based on
LOAEL findings of delayed sexual maturation in F1 males and an increase
in stillbirth in both generations) was at a dose lower than the parental
NOAEL (based on decreased body weights, body weight gains and thymus
weights).  There was an increased quantitative susceptibility in this
study, but the degree of concern is low because the study NOAEL and
LOAEL have been selected for risk assessment purposes for relevant
exposure routes and durations.  In addition, the potential immunotoxic
effects observed in the study have been further characterized with the
submission of a developmental immunotoxicity study, which showed no
evidence of susceptibility.

3.3.7	Recommendation for a Developmental Neurotoxicity Study  TC \l3
"3.3.7	Recommendation for a Developmental Neurotoxicity Study 

A developmental neurotoxicity study was submitted and reviewed by the
Agency (see Section 3.3.2).

3.3.8	Rationale for the UFDB (when a DNT is recommended)  TC \l3 "3.3.8
Rationale for the UFDB 

No database uncertainty factor is required (see Section 3.3.2)

3.4	FQPA Safety Factor for Infants and Children  TC \l2 "3.4	Safety
Factor for Infants and Children 

It is recommended that the 10X FQPA safety factor for the protection of
infants and children be reduced to 1X.  There is no increased
qualitative or quantitative susceptibility in the rat or rabbit
developmental toxicity studies.  In the rat developmental neurotoxicity
study, there was evidence of quantitative susceptibility, but the NOAEL
and LOAEL were well characterized and the doses and endpoints selected
for risk assessment are protective of the observed susceptibility.

In the two-generation reproduction study, there was increased
quantitative susceptibility as the offspring NOAEL was below the
parental NOAEL.  There was a clear difference between the NOAEL and the
LOAEL.  The observed susceptibility in the reproduction study and the
potential immunotoxicity observed in the study was the basis for the
retention of a 10X database uncertainty factor (UFDB) for the lack of
the developmental immunotoxicity study in previous risk assessments. 
However, the submitted developmental immunotoxicity study demonstrated
no treatment-related effects.

With the submission of an acceptable immunotoxicity study, HED has
concluded the 10X FQPA safety factor can be removed (reduced to 1X). 
The toxicity database is complete; despite evidence of quantitative
susceptibility in several studies, the degree of concern for the
susceptibility is low because:

Doses and endpoints selected for risk assessment are protective of the
observed effects.

The dietary food exposure assessment is not likely to underestimate
exposure/risk.

The dietary drinking water assessment utilizes water concentration
values generated by models and associated modeling parameters that are
designed to provide conservative, health protective, high-end estimates
of concentrations in water that are not likely to be exceeded.

The residential exposure assessment was conducted using standard,
health-protective assumptions.  

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) - Females age 13-49  TC \l3 "3.5.1
Acute Reference Dose (aRfD) - Females age 13-49 

Study Selected: Developmental Toxicity Study – rabbit (OPPTS 870.3700)

MRID No.: 45422713, 45422712

Dose and Endpoint for Establishing aRfD:  Developmental NOAEL = 25
mg/kg/day based on an increased litter incidence of a missing lobe of
the lung observed at the LOAEL of 75 mg/kg/day.

Uncertainty Factor(s): An UF of 100 was applied to account for
inter-species extrapolation (10X) and intra-species variation (10X).

Comments on Study/Endpint/Uncertainty Factors:

The acute dietary endpoint for females in the 13 to 49 year age group is
based on an increased litter incidence of a missing lobe of the lung. 
This developmental effect is presumed to occur following a single oral
dose and is considered an appropriate endpoint for this population
subgroup (i.e., women who could potentially be pregnant).  Other effects
observed at 75 mg/kg/day were premature deliveries, decreased gravid
uterine weights and decreased litter average for ossified sternal centra
per fetus; however, these are not considered to be single-dose effects.

	Acute RfD = 25 mg/kg/day (NOAEL) = 0.25 mg/kg/day

				100 (UF)

3.5.2	Acute Reference Dose (aRfD) - General Population  TC \l3 "3.5.2
Acute Reference Dose (aRfD) - General Population 

Study Selected:  Special neurotoxicity/pharmacology study in mice	
(Non-guideline)

MRID No.:  45422823

Dose and Endpoint for Establishing aRfD:  NOAEL = 25 mg/kg/day based on
transient signs of decreased spontaneous motor activity, tremors and
deep respirations observed at the LOAEL of 50 mg/kg/day.

Uncertainty Factor(s): An UF of 100 was applied to account for
inter-species extrapolation (10X) and intra-species variation (10X).

Comments on Study/Endpoint/Uncertainty Factors:  The acute dietary
endpoint for the general population is based on transient signs of
decreased spontaneous motor activity, tremors and deep respirations in
the mouse following a single oral dose.  This endpoint is considered
appropriate for the general population (including infants and children)
because the effects were observed following a single dose and the route
of administration (oral) is appropriate for dietary considerations.

	Acute RfD =    25 mg/kg/day (NOAEL)   = 0.25 mg/kg/day

			              100 (UF)

3.5.3	Chronic Reference Dose (cRfD)  TC \l3 "3.5.3	Chronic Reference
Dose (cRfD) 

Study Selected:  2-Generation Reproduction Toxicity Studies—rat 
(OPPTS 870.3800)

MRID No.:  45422714; 45422715 and 45422716

Dose and Endpoint for Establishing cRfD: NOAEL = 9.8 mg/kg/day based on
decreased body weight gains and delayed sexual maturation, decreased
absolute thymus weights in F1 pups and an increase in stillbirths in
both generations observed at the LOAEL of 31.2 mg/kg/day. 

Uncertainty Factor(s):  An UF of 100 was applied to account for
inter-species extrapolation (10X) and intra-species variation (10X).  

Comments on Study/Endpoint/Uncertainty Factors:  

The chronic dietary endpoint is based on offspring effects in the
two-generation reproduction study: decreased body weight gains and
delayed sexual maturation, decreased absolute thymus weights in F1 pups
and an increase in stillbirths in both generations.  This endpoint is
considered applicable for chronic dietary exposure because the route of
administration (oral) is appropriate for dietary considerations.  The
study and endpoint were selected because they are protective of effects
observed in all the other available studies that could be selected for
chronic dietary exposure assessment.

	Chronic RfD =    9.8 mg/kg/day (NOAEL)   = 0.098 mg/kg/day

			              100 (UF)

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

Study Selected:  2-Generation Reproduction Study - rat	(OPPTS 870.3800) 

MRID No.:  45422714, 45422715 and 45422716

Dose and Endpoint for  Risk Assessment:  NOAEL = 9.8 mg/kg/day based on
decreased body weight gains and delayed sexual maturation and decreased
absolute thymus weights in F1 pups in both generations at the LOAEL of
31.2 mg/kg/day.

Uncertainty Factor(s): An UF of 100 was applied to account for
inter-species extrapolation (10X) and intra-species variation (10X).

 Comments on Study/Endpoint: 

This endpoint is based on an oral study, which is the route of interest
for an incidental oral risk estimate.  The study and endpoint were
selected because they are protective of effects observed in all the
other available studies.  The endpoint is appropriate for all durations,
as the effect may be a result of either short- and/or longer-term
exposure.  In addition, it is appropriate for incidental oral exposure
because it is based on offspring effects from the reproduction study.

3.5.5	Dermal Absorption  TC \l3 "3.5.5	Dermal Absorption 

Dermal Absorption Factor:  1%.  

In a dermal penetration study (MRID 45868001), TI-435 [Clothianidin] as
the FS 600 formulation (10% a.i.) [nitroimino-14C] TI- 435), was
administered to five male Rhesus monkeys.  Test material was applied to
a shaved area (4 cmX 6 cm) of the skin on the back of each animal.  The
total dose was contained in 100 ml of test substance and was applied at
a dose of 6.13 ug/cm2.  Animals were exposed for 8 hours, and then the
application sites were washed.  Subjects were monitored for 120 hours. 
Urine and feces were collected for the exposure and the subsequent
monitoring periods.

3.5.6	Dermal Exposure (Short-, Intermediate- and Long-Term)  TC \l3
"3.5.6	Dermal Exposure (Short-, Intermediate- and Long-Term) 

Study Selected:  2-Generation Reproduction Toxicity Studies - rat (OPPTS
870.3800)

MRID No.:  45422714, 45422715 and 45422716

Dose and Endpoint for Risk Assessment: The NOAEL = 9.8 mg/kg/day based
on decreased body weight gains and delayed sexual maturation, decreased
absolute thymus weights in F1 pups and an increase in stillbirths in
both generations observed at the LOAEL of 31.2 mg/kg/day  

Comments on Study/Endpoint:  This endpoint is based on an oral study. 
No dermal studies are available.  Therefore, an oral study is selected
to estimate risk using a route-to-route extrapolation.  The study and
endpoint were selected because it is protective of effects observed in
all the available studies.  The endpoint is appropriate for all
durations as the effect may be a result of either short- and/or
longer-term exposure.  Because an oral study was selected, the dermal
absorption factor of 1% should be used for dermal risk assessment.

3.5.7	Inhalation Exposure (Short-, Intermediate- and Long-Term)  TC \l3
"3.5.7	Inhalation Exposure (Short-, Intermediate- and Long-Term) 

Study Selected:  2-Generation Reproduction Toxicity Study - rat (OPPTS
870.3800)

MRID No.:  45422714, 45422715 and 45422716

Dose and Endpoint for Risk Assessment:  The NOAEL = 9.82 mg/kg/day based
on 

Decreased body weight gains and delayed sexual maturation, decreased
absolute thymus weights in F1 pups and an increase in stillbirths in
both generations observed at the LOAEL of 31.2 mg/kg/day.

Uncertainty Factor(s): An UF of 100 was applied to account for
inter-species extrapolation (10X) and intra-species variation (10X).

Comments about the Study/Endpoint:  This endpoint is based on an oral
study.  No inhalation studies are available.  Therefore, an oral study
is selected to estimate risk using a route-to-route extrapolation.  The
study and endpoint were selected because they are protective of effects
observed in all the available studies.  The endpoint is appropriate for
all durations as the effect may be a result of either short- and/or
longer-term exposure.  Absorption via inhalation is assumed to be
equivalent to absorption via the oral route, i.e., 100% dermal
absorption is assumed in risk assessment.

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

Table 3.5.8.   Summary of Levels of Concern for 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	N/A

Inhalation	100	100	N/A

Incidental Oral	100	100	N/A



3.5.9	Recommendation for Aggregate Exposure Risk Assessments  TC \l3
"3.5.9	Recommendation for Aggregate Exposure Risk Assessments 

According to FQPA (1996), when there are potential residual exposures to
a pesticide, an aggregate risk assessment must consider exposures from 3
major routes: oral, dermal, and inhalation. 

For all durations, oral, dermal, and inhalation exposures may be
aggregated because of the selection of a common endpoint for these
routes of exposure.

3.5.10	Classification of Carcinogenic Potential  TC \l3 "3.5.10
Classification of Carcinogenic Potential 

In accordance with the EPA’s Final Guidelines for Carcinogen Risk
Assessment (March, 2005), the clothianidin is classified as “Not
Likely to be Carcinogenic to Humans.” 

A statistical analysis showed that the increase in thyroid c-cell tumors
in female rats was not significant, especially when carcinomas and
adenomas were combined.  The increased incidence of hepatocellular
carcinomas in male rats at the low and high doses are just outside
historical control incidences for the same testing laboratory (only 2
studies) but are within the historical control range for the animal
supplier.  In addition, there was no dose-response and there is no
continuum (i.e. no preneoplastic lesions and no adenomas).  Based on
these factors, it was determined that there was no evidence of
carcinogenicity in rats.  There was no evidence of carcinogenicity in
mice.

3.5.11	Summary of Toxicological Doses and Endpoints for Use in Human
Risk Assessments  TC \l3 "3.5.11	Summary of Toxicological Doses and
Endpoints for Use in Human Risk Assessments 

Table 3.5.1a.  Summary of Toxicological Doses and Endpoints for
Clothianidin for Use in Dietary and Non-Occupational Human Health Risk
Assessments.

Exposure/

Scenario	Point of Departure	Uncertainty/

FQPA Safety Factors	Level of Concern for Risk Assessment	Study and
Toxicological Effects

Acute Dietary

Females age 

13-49 	NOAEL =  

25 mg/kg/day	UFA = 10X

UFH = 10X

SFFQPA =1

 	aRfD=0.25 mg/kg/day

aPAD=0.25 mg/kg/day	Rabbit developmental  study 

LOAEL = 75 mg/kg/day based on increased litter incidence of a missing
lobe of the lung

Acute Dietary

General population	NOAEL = 

25 mg/kg/day	UFA = 10X

UFH = 10X

SFFQPA  = 1	aRfD = 0.25

mg/kg/day

aPAD 0.25

mg/kg/day	Special neurotoxicity/pharmacol

study in mice 

LOAEL = 50 mg/kg/day based on transient signs of decreased spontaneous
motor activity, tremors and deep respirations

Chronic Dietary

All populations including infants and children	NOAEL= 

9.8 mg/kg/day  	UFA = 10X

UFH = 10X

SFFQPA =1	cRfD=0.098 mg/kg/day

cPAD=0.098 mg/kg/day	2-Generation reproduction study 

LOAEL = 31.2 mg/kg/day based on decreased body weight gains and delayed
sexual maturation, decreased absolute thymus weights in F1 pups and
increased stillbirths in both generations

Incidental Oral (short and intermediate term)	NOAEL= 

9.8 mg/kg/day	UFA= 10X

UFH= 10X

SFFQPA=1	MOE= 100 (residential and occupational)	2-Generation
reproduction study 

LOAEL= 31.2  mg/kg/day based on decreased body weight gains and delayed
sexual maturation, decreased absolute thymus weights in F1 pups 

Dermal (all durations) 	Oral study NOAEL= 

9.8 mg/kg/day

(dermal absorption = 1%)	UFA= 10X

UFH= 10X

SFFQPA=1	MOE= 100 (residential and occupational)	2-Generation
reproduction study 

LOAEL = 31.2 mg/kg/day based on  decreased body weight gains and delayed
sexual maturation, decreased absolute thymus weights in F1 pups and
increased stillbirths in both generations

Inhalation (all durations)

	Oral study NOAEL= 

9.8 mg/kg/day

(inhalation absorption = 100% of oral absorption)	UFA= 10X

UFH= 10X

SFFQPA=1	MOE= 100 (residential and occupational)	2-Generation
reproduction study

LOAEL = 31.2 mg/kg/day based on decreased body weight gains and delayed
sexual maturation, decreased absolute thymus weights in F1 pups and
increased stillbirths in both generations



Cancer (oral, dermal, inhalation)	“Not Likely to be Carcinogenic to
Humans” 

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 (interspecies).  UFH =
potential variation in sensitivity among members of the human population
(intraspecies).  UFL = use of a LOAEL to extrapolate a NOAEL.  UFS = use
of a short-term study for long-term risk assessment.  UFDB = to account
for the absence of key date (i.e., lack of a critical study).  FQPA SF =
FQPA Safety Factor.  PAD = population adjusted dose (a = acute, c =
chronic).  RfD = reference dose.  MOE = margin of exposure.  LOC = level
of concern.  N/A = not applicable.

Table 3.5.1a.  Summary of Toxicological Doses and Endpoints for
Clothianidin for Use in Occupational Human Health Risk Assessments.

Exposure/

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

Dermal (all durations) (Adults)	Oral study NOAEL= 

9.8 mg/kg/day

(dermal absorption = 1%)	UFA= 10X

UFH= 10X

SFFQPA=1	MOE= 100 (residential and occupational)	2-Generation
reproduction study 

LOAEL = 31.2 mg/kg/day based on  decreased body weight gains and delayed
sexual maturation, decreased absolute thymus weights in F1 pups and
increased stillbirths in both generations

Inhalation (all durations)

	Oral study NOAEL= 

9.8 mg/kg/day

(inhalation absorption = 100% of oral absorption)	UFA= 10X

UFH= 10X

SFFQPA=1	MOE= 100 (residential and occupational)	2-Generation
reproduction study

LOAEL = 31.2 mg/kg/day based on decreased body weight gains and delayed
sexual maturation, decreased absolute thymus weights in F1 pups and
increased stillbirths in both generations



Cancer (oral, dermal, inhalation)	“Not Likely to be Carcinogenic to
Humans” 

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 (interspecies).  UFH =
potential variation in sensitivity among members of the human population
(intraspecies).  UFL = use of a LOAEL to extrapolate a NOAEL.  UFS = use
of a short-term study for long-term risk assessment.  UFDB = to account
for the absence of key date (i.e., lack of a critical study).  FQPA SF =
FQPA Safety Factor.  PAD = population adjusted dose (a = acute, c =
chronic).  RfD = reference dose.  MOE = margin of exposure.  LOC = level
of concern.  N/A = not applicable.

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 the recommendations of its Endocrine Disruptor Screening and
Testing Advisory Committee (EDSTAC), EPA determined that there was
scientific basis for including, as part of the program, the androgen and
thyroid hormone systems, in addition to the estrogen hormone system. 
EPA also adopted EDSTAC’s recommendation that the Program include
evaluations of potential effects in wildlife.  For pesticide chemicals,
EPA will use FIFRA and, to the extent that effects in wildlife may help
determine whether a substance may have an effect in humans, FFDCA
authority to require the wildlife evaluations.  As the science develops
and resources allow, screening of additional hormone systems may be
added to the Endocrine Disruptor Screening Program (EDSP).

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

Although there are possible endocrine effects associated with
clothianidin, there are no specific studies being requested at this time
because the effects have been characterized in an acceptable
2-generation reproduction study with a clear NOAEL and LOAEL as well as
in developmental studies, and the chronic reference dose (cRfD) selected
for clothianidin risk assessments is considered protective of the
observed possible endocrine effects.  To the extent that new or revised
tests are developed in connection with the EDSP that can provide more
information on endocrine effects, EPA will consider whether further
testing of clothianidin is appropriate.

4.0	Public Health and Pesticide Epidemiology Data  TC \l1 "4.0	Public
Health and Pesticide Epidemiology Data 

No public health or epidemiological data were used for this risk
assessment.

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 

The metabolism of clothainidin in primary crops, rotational crops,
livestock, and rats was evaluated by the Metabolism Assessment Review
Committee (MARC) in 2003.  The clothianidin risk assessment team concurs
with the findings of the MARC regarding the residues of concern for risk
assessment and tolerance enforcement (Table 5.1.7).

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

Adequate plant metabolism studies are available reflecting the
application of [14C]-clothianidin as a seed treatment to corn and sugar
beets, as foliar applications to apples, and as soil and foliar
applications to tomatoes.  The metabolic profiles in the tested primary
crops were similar, in that the highest level residue was the parent,
clothianidin, with the exception of mature sugar beet tops.  The
metabolic profile from the study with apple is indicative of the
metabolic profile in other plants and is believed to proceed as follows:
 (i) hydrolysis of clothianidin to form TZMU; (ii) N-demethylation of
clothianidin to form TZNG; (iii) hydroxylation of clothianidin to form
THMN and subsequent glucosylation to form THMN-Glc; (iv) N-demethylation
of TZMU to form TZU; (v) denitrification of clothianidin to form TMG;
(vi) loss of the thiazolyl-methyl moiety (C-N bond cleavage) from
clothianidin to form MNG and reduction of MNG (vii) denitrification of
MNG to form MG; and (viii) N-demethylation of MNG to form NTG.  See
D260059 (L. Croteau and Y. Donovan, 25 April 2003) for the chemical
structures of the various clothianidin metabolites.

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

Adequate confined and limited field rotational crop studies are
available.  The metabolism of clothianidin in primary and rotational
crops is similar.  Clothianidin, TZNG, and MNG are the ROCs in
rotational crops for risk assessment.  Clothianidin is the ROC for the
tolerance expression.

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

The nature of clothianidin residues in livestock is adequately
understood based on acceptable goat and hen metabolism studies. 
Metabolism in livestock involves numerous demethylation and
denitrification reactions.    TC \l3 "5.1.3	Metabolism in Livestock The
ROCs for risk assessment are parent and the metabolites TZU, TZG, TZNG,
ATMG-pyruvate (ruminants), and ATG-acetate (poultry).  For tolerance
enforcement, clothianidin is the only ROC.

5.1.4	Environmental Degradation TC \l3 "5.1.4	Environmental Degradation 

The fate and disposition of clothianidin in the environment suggest that
it is persistent and mobile, stable to hydrolysis, and has potential to
leach to ground water, as well as runoff to surface waters.  The high
persistence of clothianidin (aerobic soil metabolism and terrestrial
field dissipation half-lives ranging from half a year to several years)
may cause accumulation of the chemical in soils following repeated uses.

5.1.5	Comparative Metabolic Profile TC \l3 "5.1.5	Comparative Metabolic
Profile 

The metabolism of clothianidin is complex, with a few major (> 10% of
the total radioactive residues) and numerous minor metabolites.  The
list of terminal residues is fairly consistent across plants, goats,
hens, and rats, although the designation of major vs. minor metabolites
varies depending on the test species.  

Table 5.1.5.  Overview of clothianidin metabolic profile in plant and
animal matrices.

Residue	Rat	Hen	Goat	Corn	Sugar Beet	Rotational Crops	Apple	Tomato

Clothianidin	(	(	(	(	(	(	(	(

ACT**	(







	ATG-Ac

(*







ATG-Pyr

(







ATMG-Pyr

	(*





	ATMT

(







CTCA**	(

	(





MG	(

(	(	(	(	(

	MNG	(	(	(	(	(	(*	(	(

MTCA**	(







	NTG	(	(	(	(	(	(	(

	THMN	(





(

	THMN-Glc





	(

	TMG	(	(	(	(	(* (tops)	(	(

	TMHG

	(





	TMT

(







TZG	(	(*	(*





	TZMU	(

(	(	(	(	(

	TZNG	(	(*	(*	(	(	(*	(	(

TZU	(	(*	(*	(	(	(	(

	UREA	(	(	(





	* 	major metabolites

**	ACT, MTCA, CTCA did not show up in hen and goat because only the
nitroimino label was used.  There are also no acute studies with these
metabolites.

5.1.6	Toxicity Profile of Major Metabolites and Degradates TC \l3 "5.1.6
Toxicity Profile of Major Metabolites and Degradates 

Acute toxicity and genotoxicity data are available for ATG-acetate,
ATMG-pyruvate, TMG, TZMU, TZNG, and MNG. The toxicity of ATG-acetate and
ATMG-pyruvate appears to be similar to that of clothianidin.  Acute
toxicity tests using LD50 levels indicate that TMG, TZMU, and TZNG may
be somewhat more toxic than clothianidin.  Structurally, these three
metabolites are nearly identical to clothianidin, differing only in the
loss of a nitro and/or methyl group.  The points of departure used for
risk assessment are well below the LD50 levels observed in the acute
toxicology studies.  Given that and the structural similarity between
these metabolites and clothianidin, HED is assuming that these compounds
are toxicologically equivalent to clothianidin with respect to the
endpoints being used for risk assessment.

5.1.7	Pesticide Metabolites and Degradates of Concern TC \l3 "5.1.7
Pesticide Metabolites and Degradates of Concern 

Table 5.1.7.  Summary of Metabolites and Degradates to be included in
the Risk Assessment and Tolerance Expression.

Matrix	Residues included in Risk Assessment	Residues included in
Tolerance Expression

Plants

	Primary Crop	Leafy and Root/Tuber Vegetables:  Parent + TMG

Other crops: Parent	Parent

	Rotational Crop	Parent, TZNG, MNG	Parent

Livestock

	Ruminant	Parent, TZU, TZG, TZNG, ATMG-Pyr	Parent

	Poultry	Parent, TZU, TZG, TZNG, ATG-Ac	Parent

Drinking Water	Parent	Not Applicable



Based on the available metabolism studies, HED concluded that the nature
of the residue has been adequately delineated, and that parent only is
the residue of concern (ROC) to be used for the tolerance expression for
primary crops.  HED had previously determined that future new uses on
root crops and/or leafy vegetables will require analysis for residues of
TMG along with parent in field trial samples and that TMG should be
included as a ROC for risk assessment if significant levels of TMG were
observed.  In the current submission, residues of TMG were shown to
occur in leafy vegetables at levels approximately 10-fold below those of
clothianidin.

5.1.8	Analytical Methodology  TC \l3 "5.1.8	Analytical Methodology 

Adequate LC/MS/MS methods are available for both collecting residue
chemistry data and enforcing tolerances for clothianidin residues in
plant (Bayer Methods 00552 and 109240-1) and animal (Bayer Method 00624)
commodities.  The validated limit of quantitation (LOQ) for clothianidin
in plant commodities is 0.010 ppm, except for wheat straw (0.020 ppm),
and the validated LOQs are 0.010 ppm in milk and 0.020 ppm in animal
tissues.  All three of these methods have been reviewed by BEAD’s
Analytical Chemistry Laboratory (ACL), approved for tolerance
enforcement, and forwarded to FDA for inclusion in PAM Volume II.  More
recently, another LC/MS/MS method (Morse Method #Meth-164) was proposed
for enforcing tolerances and collecting data on residues of clothianidin
and TMG in grape and potato commodities.  This method is similar to
Method 00552 and involves extraction of residues with
acetonitrile/water, cleanup using solid phase extraction (SPE)
cartridges, and the separate analysis of clothianidin and TMG by
LC/MS/MS.  The validated LOQ for each analyte is 0.02 ppm in all grape
and potato matrices, except for potato chips and raisins (with LOQs of
0.04 ppm).  The method was adequately validated in conjunction with the
field trials and processing studies and has undergone a successful
independent laboratory validation (ILV) trial.

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

The Environmental Fate and Effects Division (EFED) provided Tier I
Estimated Drinking Water Concentrations (EDWCs) for clothianidin in
surface water and in ground water for use in human health risk
assessments (J. Meléndez, D360266, 4 August 2009).  The simulation
model FIRST was used to calculate the surface water EDWCs, and the
SCI-GROW model was used to calculate the groundwater EDWC.  No
clothianidin monitoring data were available.  Although clothianidin is a
major metabolite of thiamethoxam in plants and in animals, it was not
found in thiamethoxam environmental fate studies.  Therefore, exposure
to clothianidin in drinking water due to thiamethoxam uses is not
expected.  For the simulation models, the application rate of 0.4 lbs
a.i./A for turfgrass was used.  This rate is the highest of all the
proposed and existing uses.  The EDWCs for clothianidin in surface
waters are 7.29 ppb for acute risk scenarios and 1.35 ppb for chronic
risk.  Clothianidin EDWCs in groundwater are not expected to exceed 5.88
ppb.  Typically, HED uses the higher of the surface or groundwater
estimates for each duration when assessing dietary risk (e.g., 7.29 ppb
from surface water for acute exposures and 5.88 ppb from groundwater for
chronic exposures).

Table 5.1.9	Summary of Estimated Surface Water and Groundwater
Concentrations for Clothianidin.

Scenario	Surface Water Conc., ppb a	Groundwater Conc., ppb b

Acute	7.29	5.88

Chronic (non-cancer)	1.35	5.88

a From the Tier I FIRST model.  Input parameters are based on use of
clothianidin on turf grass.

b From the SCI-GROW model assuming a maximum seasonal use rate of 0.4 lb
ai/A, a Koc of 84, and a half-life of 744 days.



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

Valent has submitted field trial data on celery, lettuce (head and
leaf), spinach, cauliflower, cabbage, mustard greens, tomatoes, peppers,
cucumbers, cantaloupes, squash, pecans, almonds, figs, pomegranates,
cotton and soybeans supporting the proposed uses of clothianidin (50%
WDG and 2.13 lb/gal FlC) on leafy vegetables, Brassica vegetables,
fruiting vegetables, cucurbit vegetables, tree nuts, figs, pomegranates,
cotton and soybeans.  In addition, IR-4 has submitted field trial data
on cranberries and peach supporting the proposed uses of clothianidin
(50% WDG and 2.13 lb/gal FlC) on the low-growing berries, except
strawberry, Subgroup (13-07H) and peaches.

The field trial data submitted by Valent supporting repeated foliar
applications of the 50% WDG or 2.13 lb/gal FlC formulations of
clothianidin are adequate, although the maximum single application rate
used in the field trials was higher (1.5X) than the proposed rate, with
the exceptions of the tree nut, fig and pomegranate field trials.  For
both the 50% WDG and 2.13 lb/gal FlC formulations, the maximum proposed
single foliar application rate is 0.05-0.067 lb ai/A for all crops
except tree nuts (0.1 lb ai/A), figs (0.09 lb ai/A) and pomegranates
(0.09 lb ai/A), and the maximum seasonal application rate is 0.2 lb ai/A
for all proposed crops.  However, in each trial, the WDG or FLC
formulation was applied twice at a rate of 0.1 lb ai/A (1.5X proposed
single rate for most crops) for a total of 0.2 lb ai/A (1X proposed
seasonal rate).  With the exceptions of the field trial data on tree
nuts, figs and pomegranates, the residue data from Valent’s current
field trials are likely to slightly over estimate clothianidin residues.

For the proposed foliar applications, an adequate number of tests were
conducted using the 50% WDG or 2.13 lb/gal FlC formulation on the
required representative crops in the appropriate geographic regions at
~1X the proposed maximum seasonal rate, and the appropriate commodities
were collected from each test around the proposed PHIs.  Samples from
all the field trials were analyzed using adequate LC/MS/MS methods, and
the available storage stability data support the sample storage
durations and conditions.  As the proposed use directions are identical
for the 50% WDG and 2.13 lb/gal formulations, and the PHIs for the
foliar applications are >7 days, the residue data for the WDG or FlC
formulations will also support the use of either the FlC or WDG
formulations (per pending OECD residue chemistry guidelines) on
low-growing berries, tree nuts, cotton, and soybean.  For foliar
applications, HED will generally allow for translation of residue data
between water-diluted formulations (other than ECs, Mcap, and
oil-dispersion formulations) when the proposed PHI is >7 days and
residues are shown to decline at longer post-treatment intervals (per
draft, pending OECD guidelines).  Therefore, HED has no objections to
the translation of formulation-specific residue data for the proposed
uses on tuberous and corm vegetables, cotton, berries, soybeans, and
tree nuts.  However, for the other crops HED is requesting that bridging
trials be completed and submitted in order to evaluate the residue
levels resulting from these two formulations for uses with a 7-day PHI. 
Adequate residue data were provided for TMG in/on leafy and Brassica
vegetables commodities as required. 

In addition to the formulation issue, several other deficiencies were
noted in Valent’s field trial data.  First, with the exceptions of the
fig and pomegranate field trials, none of the other field trials
included the use of any adjuvants in the spray mix, although the
proposed labels allow for the use of spray adjuvants.  The foliar
applications were applied at a slightly exaggerated single rate (1.5X). 
HED has evidence that adjuvants can have a significant impact on residue
levels, potentially increasing them by 4- to 5-fold relative to residues
resulting from the same use without adjuvants.  Therefore, the 1.5X
application rate is not sufficient to address the impact of adjuvants on
residue levels.  HED requests that bridging trials be conducted to show
the impact of adjuvants on residue levels (three trials per
representative crop) and that in the mean time, the proposed label be
revised to disallow the use of spray adjuvants with clothianidin foliar
treatments, with the exception of applications to figs, pomegranates,
and tree nuts except almonds (due to residues in/on almond hulls).

Second, no residue data were submitted on soybean forage and hay
following the proposed foliar applications.  The label should be revised
to prohibit the feeding of soybean forage and hay to livestock.

at ≥21 days following a single soil application at 0.2 lb ai/A are
likely to be less than or equal to the residues resulting from repeated
foliar applications totaling 0.2 lb ai/A, insufficient data are
available to make this determination.  Based on the submitted soil
application data, HED also assumes that the desired PHI for soil
applications is 21 days, as in the studies, rather than the currently
specified 7-day PHI.

Data are insufficient to support the soil application use patterns
requested. In order to support this use pattern, HED recommends bridging
studies be conducted to examine the effects of application mode (soil
vs. foliar) on residue levels.  Given the number of variables involved
with the requested uses (adjuvant use, formulation effects, and soil vs.
foliar application), HED further recommends that the design of these
trials be discussed with HED prior to their initiation. 

Although no field trial data were submitted by Valent supporting the use
of the 5 lb/gal FlC formulation as a seed (soybean) or seed-piece
treatment (potatoes), no new residue data are required as the existing
residue data on soybeans and potatoes will support the proposed uses. 
For potatoes, adequate field trial data are available supporting an
identical use for the 2.13 lb/gal FlC formulation (DP# 303164, W. Drew,
2/1/06); these data will support the same use for the 5 lb/gal FlC
formulation.

For soybeans, the submitted field trial data reflecting foliar
applications at up to 0.2 lb ai/A/season will cover the proposed seed
treatment use, as the proposed use rate from the seed treatment would
result in a worst-case field rate of 0.05 lb ai/A.  Given the longer
harvest interval and lower use rate for the seed treatment, and the fact
that residues in/on soybean seeds were detectable in only one soybean
seed sample (0.016 ppm) at 21 days following the foliar applications,
HED concludes that the proposed seed treatment is unlikely to result in
residues greater than those resulting from the foliar use.

Although additional field trial data are being requested from Valent,
the available data support tolerances of clothianidin at 3.0 ppm on
leafy vegetables, 1.9 ppm on Brassica vegetables, 0.2 ppm on fruiting
vegetables, undelinted cottonseed, and pomegranates, 0.06 ppm on
cucurbit vegetables, 0.05 ppm on figs, 0.01 ppm on tree nuts and
pistachios, 1.5 ppm on almond hulls, 4.5 ppm on cotton gin byproducts,
and 0.02 ppm on soybean seed.  (Note: although TMG residue data will be
used for risk assessment, the tolerance for primary crop uses will
continue to include only the parent compound for enforcement purposes)

The submitted residue data for TMG in/on leafy and Brassica vegetables
and cotton gin byproducts are adequate, and the ratio of clothianidin
residues to TMG residues was relatively consistent for a given crop,
generally showing that residues of clothianidin are 10X higher than TMG
residues.

The field trial data submitted by IR-4 supporting the use of
clothianidin (WDG) on peaches and low-growing berries (except
strawberry) are also adequate, although the peach field trials used an
exaggerated single application rate (2X).  An adequate number of tests
were conducted on peaches and cranberries using the WDG formulation in
the appropriate geographic regions at ~1X the proposed maximum seasonal
rate.  The appropriate commodities were collected from each test at the
proposed PHIs.  Samples from all the field trials were analyzed using an
adequate LC/MS/MS method, and the analyses are supported by the
available storage stability data.  Although no field trial data were
submitted supporting the use of the FlC formulation on berries, the
available residue data for the WDG formulation will be translated to
support the FlC formulation as the proposed PHI for the foliar
applications is 21 days for these crops.  However, bridging data are
required for use of the FlC product on peaches.

The available peach and cranberry field trial data support the proposed
tolerances of 0.70 ppm for peaches and 0.01 ppm for low-growing berries,
except strawberry (Subgroup 13-07H).  However, for purposes of
international harmonization, HED is recommending a tolerance level of
0.80 ppm for residues of clothianidin in/on peaches.

5.1.11	International Residue Limits TC \l3 "5.1.11	International Residue
Limits 

Except for potatoes and peach/stone fruit there are currently no
established or proposed Codex, Canadian, or Mexican maximum residue
limits (MRLs) for clothianidin on the requested crops/crop groups.  For
potato and peach/stone fruit commodities, HED’s recommended tolerances
are in accord with established/recommended Canadian MRLs.  Therefore,
harmonization with international MRLs is not an issue with this
petition.  An International Residue Limit Status Sheet follows.

INTERNATIONAL RESIDUE LIMIT STATUS

Chemical Name:
(E)-N-[(2-Chloro-5-thiazolyl)methyl]-N’-methyl-N”-nitroguanidine
Common Name: Clothianidin	X Proposed tolerances

 Reevaluated tolerance

 Other	Date: 2/16/09

Codex Status (Maximum Residue Limits)	U. S. Tolerances

X No Codex proposal step 6 or above

 No Codex proposal step 6 or above for the crops requested 	Petition
Numbers: 8F7395, 8E7460,  and 9F7530

DP Numbers: 355896, 360842, and 362499

Other Identifier: PC Code 044309

Residue definition (step 8/CXL):  NA	Reviewer/Branch: M. Doherty/RAB II

	Residue definition: Clothianidin

Crop (s)	MRL (mg/kg)	Crop(s) 	Recommended Tolerance (ppm)



Vegetable, leafy, except brassica, Group 4	3.0



Vegetable, brassica, leafy, Group 5	1.9



Vegetable, fruiting, Group 8	0.2



Vegetable, cucurbits, Group 9	0.06



Fig	0.05



Nut, tree nuts, Group 14	0.01



Pistachio	0.01



Pomegranate	0.20



Almond, hulls	1.5



Cotton, undelinted seed	0.20



Cotton, gin byproducts	4.5



Soybean, seed	0.02



Peach	0.70



Berry, low-growing, except strawberry, Subgroup 13-07H	0.01





	Limits for Canada	Limits for Mexico

( No Limits

X No Limits for the crops requested	X  No Limits

(   No Limits for the crops requested

Residue definition: Clothianidin	Residue definition:  NA

Crop(s)	MRL (mg/kg)	Crop(s)	MRL (mg/kg)

  SEQ CHAPTER \h \r 1 Field corn grain	0.01



Popcorn grain	0.01



Rapeseed (canola)	0.01



Sweet corn kernel plus cob with husk removed	0.01



Milk	0.01







	Notes/Special Instructions:  Potato commodities were recently given
MRLs by Canada, as follows:  Tubers (0.3 ppm), chips (0.6 ppm), and
granules/flakes (1.5 ppm).  PMRA (Canada) is currently reviewing a
petition to establish tolerances on stone fruit, which includes peaches.
 HED’s recommended tolerance of 0.7 ppm is harmonized with PMRA’s
recommended MRL for stone fruit.



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

Acute and chronic aggregate dietary (food and drinking water) exposure
and risk assessments were conducted (M. Doherty, D364363, 11 August
2009) using the Dietary Exposure Evaluation Model DEEM-FCID™, Version
2.03 which uses food consumption data from the U.S. Department of
Agriculture’s Continuing Surveys of Food Intakes by Individuals
(CSFII) from 1994-1996 and 1998.  The analyses were performed to support
Section 3 registration requests for clothianidin and thiamethoxam.

Both the acute and chronic assessments are based on tolerance-level
residues, assume 100% crop treated, and include estimates for residues
of clothianidin in drinking water.  Clothianidin is a major metabolite
of thiamethoxam, and these analyses include thiamethoxam as a source of
clothianidin exposure.  These assessments address requests for new uses
of clothianidin as foliar treatments on berries (Subgroup 13-07H),
Brassica vegetables (Group 5), cotton, cucurbit vegetables (Group 9),
figs, fruiting vegetables (Group 8), leafy vegetables (Group 4),
peaches, pomegranates, soybeans, tuberous and corm vegetables (Subgroup
1C), tree nuts (Group 14); as seed treatments on root and tuber
vegetables (Group 1), bulb vegetables (Group 3), leafy greens (Subgroup
4A), Brassica leafy vegetables (Subgroup 5B), fruiting vegetables (Group
8), cucurbit vegetables (Group 9), and cereal grains (except rice; Group
15); and new uses of thiamethoxam on rice, sugar beets, and tropical
fruits. 

   

Based on highly conservative, health-protective assumptions, the
aggregate dietary risk estimates are below HED’s level of concern
(100% of the population-adjusted dose, PAD) for all durations and
population subgroups.  For the acute assessment, the maximum estimated
risk is for 23% of the acute PAD (aPAD).  Similarly, the maximum
estimated risk for the chronic assessment is for children 1-2 years of
age at 19% of the chronic PAD (cPAD).  Clothianidin is not a human
carcinogen; therefore, cancer risk is not an issue for this chemical. 
Dietary exposure and risk estimates are summarized in Table 5.2, below.

Table 5.2.  Summary of Dietary Exposure and Risk Estimates for
Clothianidin.

Population Subgroup	Acute (95th Pecentile of Exposure)	Chronic

	Exposure, mg/day	Risk, % aPAD	Exposure, mg/day	Risk, % cPAD

U.S. Population (total)	0.015348	6	0.004582	5

All infants (< 1 year)	0.048192	19	0.012680	13

Children 1-2 yrs	0.057589	23	0.018429	19

Children 3-5 yrs	0.039621	16	0.012188	12

Children 6-12 yrs	0.018222	7	0.005801	6

Youth 13-19 yrs	0.011109	4	0.003194	3

Adults 20-49 yrs	0.010491	4	0.003229	3

Adults 50+ yrs	0.010650	4	0.003438	4

Females 13-49 yrs	0.010991	4	0.003325	3

The population subgroup(s) with the highest exposure/risk estimates are
shown in bold.

6.0	Residential (Non-Occupational) Exposure/Risk Characterization  TC
\l1 "6.0	Residential (Non-Occupational) Exposure/Risk Characterization 

The non-occupational/residential exposure/risk assessment is based on
the HED’s previous assessment (M. Dow, D296176, 24 February 2004). 
The results of this assessment are summarized as follow:

There is a registered use for clothianidin on turf and, therefore,
residential and recreational post-application exposures are possible.

Although residential handler exposure is not expected from the currently
registered or proposed uses of clothianidin, owing to the absence of
products registered or proposed for homeowner use, the exposure
estimates in Table 6 (below) do include adult exposure from commercial
application to turfgrass via granular push-type spreader.  Therefore,
this represents an overestimate of total exposure.

The MOEs for the residential post-application exposures/risks range from
1,300 to 490,000 (Table 6.0).  MOE values greater than 100 are
considered adequate to protect adults and children from residential
non-dietary post-application exposures to clothianidin.  The estimated
MOE’s are based upon conservative assumptions and are >1000;
therefore, the estimated risks from residential non-dietary
post-application exposures do not exceed HED’s level of concern.

Table 6.0.  Summary of Residential Post-Application Exposure and Risk
Estimates.

Activity	Exposure (Dose)

mg a.i./kg bw/day	MOE

Adult dermal application	0.000026	370000

Adult dermal post-application turf contact	0.00108	9100

Adult golfer post-application turf contact	0.000075	130000

Adult combined	0.001181	8300

Toddler oral hand to mouth from contacting treated turf	0.0059	1700

Toddler incidental oral ingestion of treated soil	0.00002	490000

Toddler dermal post-application turf contact	0.00155	6300

Toddler combined	0.00747	1300



Spray drift is always a potential source of exposure to residents nearby
spraying operations.  This is particularly the case with aerial
application but, to a lesser extent, could also be a potential source of
exposure from the ground application method employed for clothianidin. 
The Agency has been working with the Spray Drift Task Force, EPA
Regional Offices and State Lead Agencies for pesticide regulation and
other parties to develop the best spray drift management practices.  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 data base submitted by the Spray
Drift Task Force, a membership of U.S. pesticide registrants, and is
developing a policy on how to appropriately apply the data and the
AgDRIFT computer model to its risk assessments for pesticides applied by
air, orchard airblast and ground hydraulic methods.  After the policy is
in place, the Agency may impose further refinements in spray drift
management practices to reduce off-target drift and risks associated
with aerial as well as other application types where appropriate.

7.0	Aggregate Risk Assessments and Risk Characterization  TC \l1 "7.0
Aggregate Risk Assessments and Risk Characterization 

7.1	Acute Aggregate Risk TC \l2 "7.1	Acute Aggregate Risk 

Other than dietary exposure, there are no other sources of exposure that
constitute an acute exposure scenario; therefore, acute aggregate
exposure and risk estimates are equivalent to the acute dietary exposure
and risk estimates summarized in Table 5.2 and are below HED’s level
of concern.

7.2	Short- and Intermediate-Term Aggregate Risk TC \l2 "7.2	Short- and
Intermediate-Term Aggregate Risk 

All of the short- and intermediate-term aggregate MOEs are greater than
100 (Table 7.2) and, therefore, represent risks that are below HED’s
level of concern.

Table 7.2.  Summary of the Short- and Intermediate-Term Aggregate
Exposure and Risk Estimates for Clothianidin.

Population Subgroup	Total Residential Exposure, mg/kg/day	Chronic
Dietary Exposure, mg/kg/day	Aggregate Exposure1, mg/kg/day	MOE2

U.S. Population (total)	0.001181	0.004582	0.005763	1700

All infants (< 1 year)	0.00747	0.012680	0.020150	480

Children 1-2 yrs	0.00747	0.018429	0.025899	380

Children 3-5 yrs	0.00747	0.012188	0.019658	500

Children 6-12 yrs	0.001181	0.005801	0.006982	1400

Youth 13-19 yrs	0.001181	0.003194	0.004375	2200

Adults 20-49 yrs	0.001181	0.003229	0.004410	2200

Adults 50+ yrs	0.001181	0.003438	0.004619	2100

Females 13-49 yrs	0.001181	0.003325	0.004506	2200

The population subgroup with the highest estimated exposure/risk is
bolded.

1 Aggregate Exposure = Residential Exposure + Chronic Dietary Exposure

2 Aggregate MOE = NOAEL (9.8 mg/kg/day) ÷ Aggregate Exposure
(mg/kg/day)

7.3	Long-Term Aggregate Risk TC \l2 "7.3	Long-Term Aggregate Risk 

Other than dietary exposure, there are no other sources of exposure that
constitute a long-term exposure scenario; therefore, long-term aggregate
exposure and risk estimates are equivalent to the chronic dietary
exposure and risk estimates summarized in Table 5.2 and are below
HED’s level of concern.

7.4	Cancer Risk TC \l2 "7.4	Cancer Risk 

Clothianidin has been classified as “not likely to be carcinogenic to
humans.”  Therefore, cancer risk is not a concern for this chemical.

8.0	Cumulative Risk Characterization/Assessment  TC \l1 "8.0	Cumulative
Risk Characterization/Assessment 

Clothianidin is a member of the neonicotinoid class of pesticides and is
a major metabolite of another neonicotinoid, thiamethoxam.  Structural
similarities or common effects do not constitute a common mechanism of
toxicity.  Evidence is needed to establish that the chemicals operate by
the same, or essentially the same, sequence of major biochemical events
(EPA, 2002).  Although clothianidin and thiamethoxam bind selectively to
insect nicotinic acetylcholine receptors (nAChR), the specific binding
site(s)/receptor(s) for clothianidin, thiamethoxam and the other
neonicotinoids are unknown at this time.  Additionally, the commonality
of the binding activity itself is uncertain, as preliminary evidence
suggests that clothianidin operates by direct competitive inhibition,
while thiamethoxam is a non-competitive inhibitor.  Furthermore, even if
future research shows that neonicotinoids share a common binding
activity to a specific site on insect nAChRs, there is not necessarily a
relationship between this pesticidal action and a mechanism of toxicity
in mammals.  Structural variations between the insect and mammalian
nAChRs produce quantitative differences in the binding affinity of the
neonicotinoids towards these receptors which, in turn, confers the
notably greater selective toxicity of this class towards insects,
including aphids and leafhoppers, compared to mammals.  While the
insecticidal action of the neonicotinoids is neurotoxic, the most
sensitive regulatory endpoint for clothianidin is based on unrelated
effects in mammals, including changes in body and thymus weights, delays
in sexual maturation, and still births.  Additionally, the most
sensitive toxicological effect in mammals differs across the
neonicotinoids (such as testicular tubular atrophy with thiamethoxam,
and mineralized particles in thyroid colloid with imidacloprid).  Thus,
there is currently no evidence to indicate that neonicotinoids share
common mechanisms of toxicity, and EPA is not following a cumulative
risk approach based on a common mechanism of toxicity for the
neonicotinoids.  For information regarding EPA’s efforts to determine
which chemicals have a common mechanism of toxicity, and to evaluate the
cumulative effects of such chemicals, see the policy statements
concerning common mechanism determinations, and procedures for
cumulating effects from substances found to have a common mechanism,
released by OPP on EPA’s website at   HYPERLINK
"http://www.epa.gov/pesticides/cumulative/" 
http://www.epa.gov/pesticides/cumulative/ .

Note that because clothianidin is a major metabolite of thiamethoxam,
EPA has combined exposure to clothianidin resulting both from
thiamethoxam use, and from use of clothianidin as an active ingredient,
and has compared this aggregate exposure estimate to relevant endpoints
for clothianidin.  Labeling for formulations containing either of these
compounds specifies that other neonicotinoid insecticides are not to be
applied during the growing season (i.e., a crop treated with
clothianidin will not be treated with thiamethoxam).  Given that, in
combination with the assumption of 100% crop treated for both the acute
and chronic dietary assessments, obviates the need to do a combined
assessment for crops with approved uses of both clothianidin and
thiamethoxam.

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

Based on the proposed use patterns, handler and post-application
exposures to clothianidin may occur.  In terms of duration, exposures
are expected to be of short- or intermediate-term duration; long-term (>
6 months) exposures are not expected to occur.

9.1	Short- and Intermediate-Term Handler Risk  TC \l2 "9.1	Short- and
Intermediate-Term Handler Risk 

Handler exposures may occur during foliar and seed-treatment uses. 
Exposure and risk estimates for handlers are based on SOPs developed by
HED’s Exposure Science Advisory Council and on data in the Pesticide
Handler’s Exposure Database (PHED).  Handler exposure and risk
estimates are summarized in Table 9.1.1 and 9.1.2, below, for the foliar
and seed treatment uses, respectively.  For a complete description of
the handler exposure analysis, see D363340 (S. Wang, 17 June 2009).

There are 12 handler scenarios that are expected to result in the
highest exposure for the proposed foliar and seed-treatment uses:

Mixing/Loading Dry Flowable for Ground-boom Applications (Scenario 1)

Mixing/Loading Dry Flowable for Airblast Applications (Scenario 2)

Mixing/Loading Dry Flowable for Chemigation (Scenario 3)

Mixing/Loading Liquid for Ground-boom Applications (Scenario 4)

Mixing/Loading Liquid for Airblast Applications (Scenario 5)

Mixing/Loading Liquid for Chemigation (Scenario 6)

Applying Sprays with Ground-boom Equipment (Scenario 7)

Applying Sprays with Airblast Equipment (Scenario 8)

Loading (Open)/Applying Liquid for Seed Treatment (Scenario 9) 

Sewing Seeds after Seed Treatment (Scenario 10)

Bagging Seeds after Seed Treatment (Scenario 11)

Multiple Activities Worker for Seed Treatment (Scenario 12)

All of the resulting occupational handler MOEs are greater than 100,
indicating that risks associated with the above exposure scenarios are
below HED’s level of concern.

Table 9.1.  Occupational Handler Risk Estimates for the Requested Foliar
Uses of Clothianidin.

Exposure Scenario (Scenario #)	Personal Protective Equip.a	Dermal Unit
Exposureb (mg/lb ai)	Inhalation Unit Exposurec   (ug/lb ai)	Crop
Application Rate

(lb ai/A)	Amount Treatedd

(A/day)	Daily

Dermal

Dosee (mg/kg/day)	Daily

Inhalation

Dosef (mg/kg/day)	Combined

Daily Doseg (mg/kg/day)	MOEh  

Mixer/Loader

Dry Flowables for 

ground-boom (1)	Baseline	0.066	0.77	Vegetables, Cott/Soybn, Cranberry i
0.06             	80         200         80	4.53 E-5 0.000113     4.53
E-5	5.28 E-5  0.000132    5.28 E-5      	9.81 E-5  0.000245    9.81 E-5
100,000  40,000  100,000

Dry Flowables for 

airblast (2)	

Baseline	0.066	0.77	Tree nuts, Figs/Pomgnt Peach i	0.1	40	3.77 E-5
0.000044	0.000082	120,000

Dry Flowables for 

chemigation (3)	Baseline	0.066	0.77	Vegetables, Cranberry	0.2	350
0.00066	0.00077	0.00143	6,900

Liquid for 

ground-boom (4)	Baseline	2.9	1.2	Vegetables, Cott/Soybn, Cranberry i
0.06             	80         200         80	0.001989   0.004971   
0.001989     	8.23 E-5  0.000206    8.23 E-5  	0.0021      0.0052   
0.0021	4,700         1,900         4,700         

Liquid for 

airblast (5)	Baseline	2.9	1.2	Tree nuts, Figs/Pomgnt Peach i	0.1	40
0.001657	6.86 E-5	0.0017	5,700

Liquid for 

chemigation (6)	Baseline	2.9	1.2	Vegetables, Cranberry	0.2	350	0.029
0.0012	0.030	320

Applicator



Sprays with 

ground-boom  (7)	Baseline	0.014	0.74	Vegetables, Cott/Soybn, Cranberry i
0.06	80         200         80	9.6 E-6   0.000024      9.6 E-6	5.07 E-5 
0.000127     5.07 E-5	0.000060  0.00015     0.000060	160,000  65,000  
160,000



Sprays with 

airblast (8)	Baseline	0.36	4.5	Tree nuts, Figs/Pomgnt Peach i	0.1	40
0.000206	0.000257	0.00046	21,000

a	Baseline consists of long-sleeve shirt, long pants, shoes, and socks
and no respirator.  PPE consists of long-sleeve shirt, long pants,
shoes, socks, chemical-resistant gloves, and no respirator.

b	Baseline Dermal Unit Exposure represents long pants, long sleeved
shirt, no gloves, open mixing/loading, and open cab tractors, as
appropriate.  

c	Baseline Inhalation Exposure represents no respiratory protection,
open mixing/loading, and open cab tractors, as appropriate.  

d	Daily acres treated values are from EPA estimates of acreage that
could be treated or volume handled in a single day for each exposure
scenario of concern, based on the application method and
formulation/packaging type.

e	Daily dermal dose (mg/kg/d) =  [unit dermal exposure (mg/lb ai) *
dermal absorption (0.01) * application rate (lb ai/acre) * daily acres
treated /  body weight (70 kg).

f	Daily inhalation dose (mg/kg/d) = (unit exposure (µg/lb ai) *
(1mg/1000 µg) conversion * application rate (lb ai/acre) * daily acres
treated / body weight (70 kg).

g	Combined daily dose = daily dermal dose + daily inhalation dose.

h	MOE = NOAEL (9.8 mg/kg/d) / combined daily dose.  UF = 100.

i                Vegetables=brassica veg+cucurbit veg+fruiting veg+leafy
veg; Cott=cotton; Soybn=soybean; Pomgnt=pomegranate. 



Table 9.2.  Occupational Handler Risk Estimates for the Requested
Soybean Seed-Treatment Use of Clothianidin.



Exposure Scenario (Scenario #)	

Personal Protective Equipment	

Dermal Unit Exposure (mg/lb ai)	

Inhalation Unit Exposure   (mg/lb ai)	

Seed Species	

Application Rate

(lb ai  per lb seed)	

Amount Treateda

(lb seed trt per day)	

Daily

Dermal

Dose b (mg/kg/day)	

Daily

Inhalation

Dosec (mg/kg/day)	

Combined Daily Dosed  (mg/kg/day)	

MOEe  



Loader/Applicator



Loading/Applying

Liquids for 

Seed Treatment (9)	

Single Layer, Gloves	0.023	0.00034	Soybean  	0.0005	718,000	0.0012
0.0017	0.0029	3,400



Sewer



Sewing Seeds after Seed treatment (10)	

Single Layer, 

No Gloves	0.0062	0.00023	Soybean  	0.0005	718,000	0.00032	0.0012	0.0015
6,500



Bagger



Bagging Seeds after Seed treatment (11)	

Single Layer, 

No Gloves	0.0091	0.00016	Soybean  	0.0005	718,000	0.00047	0.00082	0.0013
7,600



Multiple Activities Worker



Multiple Activities for Seed treatment (12)	

Single Layer, Gloves	0.042	0.0016	Soybean  	0.0005	718,000	0.0022	0.0082
0.0104	950

a	Daily amounts treated values are based on the information provided by
the Registrant through Registration Division. 

b	Daily dermal dose (mg/kg/d) =  [unit dermal exposure (mg/lb ai) *
dermal absorption (0.01) * application rate (lb ai/lb seed) * daily
amounts treated /  body weight (70 kg).

c	Daily inhalation dose (mg/kg/d) = (unit exposure (mg/lb ai) *
application. rate (lb ai/lb seed) * daily amounts treated / body weight
(70 kg).

d	Combined daily dose (mg/kg/d) =  Daily dermal dose (mg/kg/d) + Daily
inhalation dose (mg/kg/d).

e	MOE = NOAEL (9.8  mg/kg/d) / combined daily dose.  UF = 100.



9.2	Short- and Intermediate-Term Post-Application Risk  TC \l2 "9.2
Short- and Intermediate-Term Post-Application Risk 

Post-application exposures may occur during farming activities in
treated fields as well as from the handling of treated seeds (secondary
seed handling).  As with the handler occupational exposure and risk
estimates, the post-application risk estimates are detailed in the
assessment by S. Wang (D 363340, 17 June 2009).  All post-application
MOEs are greater than 100 and reflect risk estimates that are below
HED’s level of concern.  The post-application MOEs are summarized in
Tables 9.2.1 and 9.2.2.

Table 9.2.1.  Post-Application Risk Estimates Associated with the
Requested Foliar Uses of Clothianidin at Zero Days after Treatment.

Crop	Application Rate 

(lb ai/A)	Work Activity	Transfer Coefficientsa (cm2/hr)	DFRc

(µg/cm2)	Daily Dosed (mg/kg/day)	 MOE e 

Cotton,

Soybean	0.06	irrigation, scouting, thinning, weeding immature plants	100
0.135	0.000015	640,000



irrigation, scouting, weeding mature plants	1500	0.135	0.00023	42,000

Cranberry	0.06	irrigation, scouting, weeding, pruning, thinning	400
0.135	0.000062	160,000



harvesting, hand pruning, pinching, training	1500	0.135	0.00023	42,000

Brassica Veg. Cucurbit Veg. Leafy  Veg.	0.06	irrigation, scouting,
thinning, weeding immature plants	500	0.135	0.000077	130,000



irrigation, and scouting mature plants	1500	0.135	0.00023	42,000



hand harvesting,  pruning, and thinning mature plants	2500	0.135	0.00038
25,000

Fruiting Veg.	0.06	irrigation, scouting, thinning, weeding immature
plants	500	0.135	0.000077	130,000



irrigation, and scouting mature plants	700	0.135	0.00011	91,000



hand harvesting, pruning, staking, tying	1000	0.135	0.00015	64,000

Figs,         Peach	0.1	propping	100	0.224	0.000026	380,000



irrigation, scouting, weeding 	1000	0.224	0.00026	38,000



Harvesting, pruning, training, tying	1500	0.224	0.00038	25,000

Pomegranate	0.1	propping	100	0.224	0.000026	380,000



irrigation, scouting, hand weeding, harvesting, pruning, training 	1500
0.224	0.00038	25,000



Thinning, tying	3000	0.224	0.00077	13,000

Tree Nuts 	0.1	irrigation, scouting, thinning, weeding	500	0.224	0.00013
76,000



harvesting/poling, pruning, thinning	2500	0.224	0.00064	15,000

a	Transfer coefficient from Science Advisory Council for Exposure:
Policy Memo #003 "Agricultural Transfer Coefficients," 05/07/98.

b	Day after treatment represents approximately 12 hours following
application  when sprays have dried.

c	DFR = Application Rate (lb ai/acre)X Fraction of active ingredient
that remains on the foliage when sprays have dried X 4.54E8 µg/lbX
24.7E-9 acre/cm2.

d	Daily dose = DFR (µg/cm2)X TC (cm2/hr)X conversion factor (1 mg/1,000
µg)X exposure time (8 hrs/day)X dermal absorption (0.01) / body weight
(70 kg).

e	MOE = NOAEL (9.8 mg/kg/day) / daily dose (mg/kg/day).

Table 9.2.2.  Risk Estimate for Secondary Seed Handlers of Treated
Soybean Seed.

Mitigation Level	Dermal Unit Exposure (mg/lb ai)	Inhalation Unit
Exposure   (mg/lb ai)	Application Rate

(lb ai  per lb seed)	Amount Planteda

(lb seed pnted/day)	Daily

Dermal

Dose b (mg/kg/day)	Daily

Inhalation

Dosec (mg/kg/day)	Combined Daily Dosed (mg/kg/day) 	MOEe  

Single Layer, Gloves	0.25	0.0034	0.0005	12,000	0.00021	0.00029	0.0005
20,000

a	Daily amounts planted values are based on the information provided by
the Registrant through Registration Division. 

b	Daily dermal dose (mg/kg/d) =  [unit dermal exposure (mg/lb ai) *
dermal absorption (0.01) * application rate (lb ai/lb seed) * daily
amounts treated /  body weight (70 kg).

c	Daily inhalation dose (mg/kg/d) = (unit exposure (mg/lb ai) *
application. rate (lb ai/lb seed) * daily amounts treated / body weight
(70 kg).

d	Combined daily dose (mg/kg/d) =  Daily dermal dose (mg/kg/d) + Daily
inhalation dose (mg/kg/d).

e	MOE = NOAEL (9.8 mg/kg/d) / combined daily dose.  UF = 100.			

10.0	Data Needs and Label Recommendations  TC \l1 "10.0	Data Needs and
Label Recommendations 

10.1	Toxicology  TC \l2 "10.1	Toxicology 

None.

10.2	Residue Chemistry  TC \l2 "10.2	Residue Chemistry 

	•	Label directions for Valent’s 50% WDG and 2.13 lb/gal FlC
formulations should be amended to include rotational crop restrictions.

 

	•	Label directions for Valent’s 50% WDG and 2.13 lb/gal FlC
formulations should be revised to remove the soil application for
vegetable crops.

	•	Label directions for both the seed treatment and foliar application
uses on soybeans should be amended to prohibit the grazing or feeding
for soybean forage and hay to livestock.

	•	Label directions for all crops except fig, pomegranate, soybeans
and tree nuts (excluding almonds) should be revised to prohibit the use
of adjuvants.  If the petitioner wants to allow the use of adjuvants,
side-by-side trials should be conducted.  HED recommends that the
petitioner consult with the Agency prior to conducting any such trials.

	•	To support the use of clothianidin (WDG or FlC) as a soil
application on vegetable crops, bridging studies are required on
selected vegetable crops to compare residues resulting from soil vs.
foliar applications.  Additional field trials are required on leaf
lettuce, mustard greens, peppers, and cucumbers (3 tests for each crop).
 In each test, clothianidin (WDG or FlC) should be applied separately to
side-by-side plots as either a single soil application at 0.2 lb ai/A,
or as three foliar applications at 0.067 lb ai/A/application at a RTI of
7 days, for a total of 0.2 lb ai/A/season.  Samples of each commodity
should be harvested at 21 DAT for the soil application and at 7 DAT for
the foliar applications.  The foliar applications should also include
the use of spray adjuvants in each test.  If residues resulting from the
soil application are greater than those coming from the foliar use, a
full set of trials reflecting residues from soil applications will be
required.

	•	The available field trial data reflect the use of the WDG
formulation on leafy vegetables, Brassica vegetables, fruiting
vegetables, cucurbit vegetables, peaches, low-growing berries (except
strawberry), tree nuts, cotton, and soybeans; and of the FlC formulation
on figs and pomegranates.  Of these, translation between formulations
for the foliar uses on cotton, berries, legume vegetables, and tree nuts
is appropriate since the PHI for these uses is greater than one week. 
For the other uses, side-by-side trials should be conducted to
demonstrate equivalency of formulations, with respect to residue levels,
if registrations for both formulations are desired.  Due to these
formulation issues and the adjuvant issues noted above, HED recommends
that the petitioner consult with the Agency prior to initiating any
side-by-side residue trials.

	•	A revised Section F should be submitted amending the proposed
tolerances to reflect the recommendations made by HED in Table 10. 
Additionally, the tolerance expression should be revised to read as
follows:

		Tolerances are established for residues of the insecticide
clothianidin, including its metabolites and degradates, in or on the
commodities in the table below as a result of the application of
clothianidin.  Compliance with the tolerance levels specified below is
to be determined by measuring only clothianidin
[(E)-N-[(2-Chloro-5-thiazolyl)methyl]-N’-methyl-N”-nitroguanidine]
in or on the commodity.

Although additional field trial data are being requested, sufficient
data are available to support permanent tolerances on the requested
commodities.  HED recommends establishing permanent tolerances for
residues of clothianidin as detailed in Table 10.  Note that HED is
currently evaluating other petitions for clothianidin requesting
registration of seed-treatment uses.  

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

None.

Table 10. 	Tolerance Summary for Clothianidin

Commodity	Proposed/Existing

Tolerance (ppm)	Recommended Tolerance (ppm)	Comments; 

Correct Commodity Definition

Leafy vegetables, Crop Group 4	3.5	3.0	Adequate data from the foliar
application use are available on lettuce (head and leaf), celery and
spinach.

Vegetable, leafy, except brassica, Group 4

Brassica (Cole) vegetables, Crop Group 5	3.0	1.9	Adequate data from the
foliar application use are available on cabbage, cauliflower and mustard
greens.

Vegetable, brassica, leafy, Group 4

Fruiting vegetables, Crop Group 8	0.25	0.20	Adequate data from the
foliar application use are available on tomatoes and peppers (Bell and
non-Bell).

Vegetable, fruiting, Group 8

Cucurbits vegetables, Crop Group 9	0.05	0.06	Adequate data from the
foliar application use are available on cucumbers, cantaloupes and
summer squash.

Vegetable, cucurbits, Group 9

Crop Sub-Group 13-07H	0.01	0.01	Adequate data are available on
cranberries.

Berry, low-growing, except strawberry, Subgroup 13-07H

Tree nuts, Crop Group 14	0.01	0.01	Adequate data are available on
almonds and pecans.  Nut, tree, Group 14.

A separate tolerance is also required for Pistachio.

Pistachio	None	0.01

	Almond, hulls	1.5	1.5	Adequate data are available on almonds.

Fig	0.05	0.05	Adequate data are available on figs.

Pomegranate	0.20	0.20	Adequate data are available on pomegranates.

Peach	0.70	0.80	Adequate data are available on peaches.  0.8 ppm is
being recommended for harmonization purposes.

Cotton, seed	0.25	0.20	Adequate data are available on cotton.

Cotton, undelinted seed

Cotton, gin byproducts

Cotton, gin byproducts	4.5	4.5

	Cotton, meal	0.25	None	Adequate cotton seed processing data are
available.  As residues were reduced in meal, hulls and oil, separate
tolerances are not required.

Cotton, hulls	0.25	None

	Cotton, refined oil	0.01	None

	Soybean, seed	0.03	0.02	Adequate data are available

Soybean, hulls	0.35	None	Adequate soybean processing data are available
indicating that quantifiable residues are unlikely to occur in soybean
processed fractions

Soybean, meal	0.07	None

	Soybean, oil	0.01	None

	Tomato, paste	0.08	None	Adequate processing data are available on
tomato indicating that separate tolerances are not required for tomato
puree and paste.

Tomato, puree	0.07	None

	Vegetable, tuberous and corm, Subgroup 1C	0.05	0.3	Adequate residue
data are available on potatoes to support a subgroup tolerance on
tuberous and corm vegetables.

Once the subgroup tolerance is established the separate tolerance on
potatoes can be deleted.  The recommended tolerances are harmonized with
current and/or pending MRLs in Canada, and are based on seed piece
treatments.  That use produces the highest residue.

Potato	0.05	delete

	Potato, chips	None	0.6

	Potato, granules/flakes	None	1.5

	

References:  TC \l1 "References: 

D260059.	Clothianidin- Briefing Memorandum for Meeting of Metabolism
Assessment Review Committee.  Y. Donovan, et al.  25 April 2003

D296176.	Clothianidin - Exposure/Risk Assessment for the Proposed New
Uses of Clothianidin on Turfgrass, Landscape Ornamentals and Tobacco. 
M. Dow.  24 February 2004.

D303164.	Clothianidin. Tolerance Petition Requesting Food Use of the
Insecticide Clothianidin on Grapes, Potatoes, Sorghum, and Cotton
(Section 3 Registration). Summary of Analytical Chemistry and Residue
Data.  W. Drew.  1 February 2006.

D335355.	Clothianidin. Tolerance Petition Requesting the Establishment
of Permanent Tolerances (Associated with Section 3 Registration) for
Food/Feed Use of the Insecticide as a Seed Treatment on Sugar Beets.
Resolution of Rotational Crop Data Deficiency. Summary of Analytical
Chemistry and Residue Data.  W. Drew.  16 October 2007.

D355896.	Clothianidin; Petitions for Tolerances and Uses on Berries
Subgroup 13-07H, Brassica Vegetables, Cotton, Cucurbit Vegetables, Figs,
Fruiting Vegetables, Leafy Vegetables, Peaches, Pomegranates, Soybeans,
Tuberous and Corm Vegetables, and Tree Nuts.  Summary of Analytical
Chemistry and Residue Data.  M. Doherty.  30 July 2009

D363340.	Clothianidin: Occupational and Residential Exposure/Risk
Assessment of Clothianidin for Section 3 Registration of New Uses on
Vegetables, Cotton, Soybean, Tree Nuts, Figs, Pomegranate, Cranberry and
Peach.  S. Wang.  17 June 2009.

D364363.	Clothianidin Acute and Chronic Aggregate Dietary (Food and
Drinking Water) Exposure and Risk Assessments.  M. Doherty.  11 August
2009.



Appendix A:	Toxicology Assessment  TC \l1 "Appendix A:	Toxicology
Assessment 

A1.	Toxicology Data Requirements TC \l2 "A1.	Toxicology Data
Requirements 

The requirements (40 CFR 158.340) for food uses for clothianidin are in
Table 1. Use of the new guideline numbers does not imply that the new
(1998) guideline protocols were used.

Test 

	Technical

	Required	Satisfied

870.1100    Acute Oral Toxicity	

870.1200    Acute Dermal Toxicity	

870.1300    Acute Inhalation Toxicity	

870.2400    Primary Eye Irritation	

870.2500    Primary Dermal Irritation	

870.2600    Dermal Sensitization		yes

yes

yes

yes

yes

yes	yes

yes

yes

yes

yes

yes

870.3100    Oral Subchronic (rodent)	

870.3150    Oral Subchronic (nonrodent)	

870.3200    21-Day Dermal	

870.3250    90-Day Dermal	

870.3465    90-Day Inhalation		yes

yes

yes

no

no	yes

yes

yes

-

-

870.3700a  Developmental Toxicity (rodent)	

870.3700b  Developmental Toxicity (nonrodent)	

870.3800    Reproduction		yes

yes

yes	yes

yes

yes

870.4100a  Chronic Toxicity (rodent)	

870.4100b  Chronic Toxicity (nonrodent)	

870.4200a  Oncogenicity (rat)	

870.4200b  Oncogenicity (mouse)	

870.4300    Chronic/Oncogenicity		yes

yes

yes

yes

yes	yes

yes

yes

yes

yes

870.5100    Mutagenicity—Gene Mutation - bacterial	

870.5300    Mutagenicity—Gene Mutation - mammalian	

870.5xxx    Mutagenicity—Structural Chromosomal Aberrations	

870.5xxx    Mutagenicity—Other Genotoxic Effects		yes

yes

yes

yes	yes

yes

yes

yes

870.6100a  Acute Delayed Neurotox. (hen)	

870.6100b  90-Day Neurotoxicity (hen)	

870.6200a  Acute Neurotox. Screening Battery (rat)	

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

870.6300    Develop. Neuro		no

no

yes

yes

yes	-

-

yes

yes

yes

870.7485    General Metabolism	

870.7600    Dermal Penetration	

870.7800   
Immunotoxicity..........................................................
....	yes

yes

yes	yes

yes

yes

Special Studies

Developmental Immunotoxicity		

yes	

yes

A2.	Toxicity Profiles TC \l2 "A2.	Toxicity Profiles 

Table A.2.1	Acute Toxicity Profile - Clothianidin Technical,
Intermediates, and Metabolites

  SEQ CHAPTER \h \r 1 Test Material	Guideline No.	Study Type	MRID(s)
Results	Toxicity Category

  SEQ CHAPTER \h \r 1 Technical	870.1100	Acute oral - rat	45422621	LD50
> 5000 mg/kg	IV

BN0230M  Metabolite	870.1100	Acute oral - rat	45422628	LD50 > 2000 mg/kg
(♂+♀)	III

BN0335E2 Metabolite	870.1100	Acute oral - rat	45422623	LD50 > 2000 mg/kg
(♂+♀)	III

MAI 

Metabolite	870.1100	Acute oral - rat	45422629	LD50 = 758 mg/kg (♀)

Males not more susceptible	III

Clothianidin-CCMT-

Adduct Intermediate	870.1100	Acute oral - rat	45422630	LD50 > 2000 mg/kg
(♂+♀)	III

Clothianidin-Hexahydropyrimidine Intermediate	870.1100	Acute oral - rat
45422631	LD50 > 2000 mg/kg (♂+♀)	III

Clothianidin-Triazan Intermediate	870.1100	Acute oral - rat	45422632
LD50 > 2000 mg/kg (♂+♀)	III

TMG Metabolite	870.1100	Acute oral - rat	45422625	LD50 < 550 mg/kg (♂)

LD50 = 567 mg/kg (♀)	II

TZMU Metabolite	870.1100	Acute oral - rat	45422624	LD50 = 1424 mg/kg
(♂)

LD50 = 1282 mg/kg (♀)	III

TZNG Metabolite	870.1100	Acute oral - rat	45422626	LD50 > 1450 mg/kg
(♂)

LD50 = 1481mg/kg (♀)	III

Technical	870.1100	Acute oral - mouse	45422622	LD50 = 389 mg/kg (♂; 

95% C.I. = 380-475)

LD50 = 465 mg/kg (♀;

95% C.I. =   SEQ CHAPTER \h \r 1 384-561)

LD50 = 425 mg/kg (♂+♀;

95% C.I. =   SEQ CHAPTER \h \r 1 380-475)	II

Technical	870.1200	Acute dermal - rat	45422634	LD50 > 2000 mg/kg	III

Technical	870.1300	Acute inhalation	45422636	LC50 >   SEQ CHAPTER \h \r
1 5.538 mg/L (♂+♀)	IV

Technical	870.2400	Acute eye irritation	45422701	  SEQ CHAPTER \h \r 1
Slightly irritating to the eye	IV

Clothianidin-CCMT- Adduct Intermediate	870.2400	Acute eye irritation
45422814	  SEQ CHAPTER \h \r 1 Not irritating to the eye	IV

Clothianidin-Triazan Intermediate	870.2400	Acute eye irritation	45422819
  SEQ CHAPTER \h \r 1 Not irritating to the eye	IV

Technical	870.2500	Acute dermal irritation	45422703	  SEQ CHAPTER \h \r
1 Not irritating to the skin	IV

Clothianidin-CCMT- Adduct Intermediate	870.2500	Acute dermal irritation
45422813	  SEQ CHAPTER \h \r 1 Not irritating to the skin	IV

Clothianidin-Triazan Intermediate	870.2500	Acute dermal irritation
45422820	  SEQ CHAPTER \h \r 1 Not irritating to the skin	IV

Technical	870.2600	Skin sensitization	45422705	  SEQ CHAPTER \h \r 1 Is
not a sensitizer under conditions of study	N/A

Clothianidin-CCMT- Adduct Intermediate	870.2600	Skin sensitization
45422815	  SEQ CHAPTER \h \r 1 Is not a sensitizer under conditions of
study	N/A

Clothianidin-Triazan Intermediate	870.2600	Skin sensitization	45422821	 
SEQ CHAPTER \h \r 1 Is a sensitizer under conditions of study	N/A



Table A.2.2.	  Subchronic, Chronic and Other Toxicity Profile  for
Clothianidin

Guide line	Study Title	MRID	Results

870.3100	90-Day Oral Toxicity - rat (diet)	45422809

(2000)

45422708

(4-week)

Acceptable/

guideline

ppm=0, 150, 500  & 3000

mg/kg/day (M/F)=0/0, 9.0/10.9, 27.9/34.0, 202.0/254.2	NOAEL =   SEQ
CHAPTER \h \r 1 27.9/34.0 mg/kg/day   SEQ CHAPTER \h \r 1 (M/F)    

LOAEL =   SEQ CHAPTER \h \r 1 202.0/254.2 mg/kg/day (M/F) 

based on   SEQ CHAPTER \h \r 1 decreased BW and BW gain.

870.3150	13-Week Oral Toxicity- dog (diet)	45422810

2000

45422808

2000

4-week

45422811

1998

palatability

Acceptable/

guideline

ppm=0, 325, 650, 1500 & 2250

mg/kg/day

(M/F)=0/0, 9.2/9.6, 19.3/21.2, 40.9/42.1, 58.2/61.8  	NOAEL = 19.3/42.1
mg/kg/day (M/F) 

LOAEL = 40.9/61.8 mg/kg/day (M/F) based on thinness, decreased body
weight, body weight gain and anemia (1 M); and on decreased white blood
cells, albumin, and total protein (F).

870.3200	28-Day Dermal Toxicity - rat	45422707 (2000)

Acceptable/

guideline

mg/kg/day= 0, 100, 300 & 1000	NOAEL = 1000 mg/kg/day (HDT)

LOAEL = Not established

870.3700a	Developmental Toxicity- rat (gavage)	45422711 (1998)

45422710 (1998)

range-finding

Acceptable/

guideline

mg/kg/day=0, 10, 40 & 125	Maternal NOAEL = 10 mg/kg/day

Maternal LOAEL = 40 mg/kg/day based on decreased body weight gain and
food consumption.

Developmental NOAEL = 125 mg/kg/day (HDT)

Developmental LOAEL = Not established

870.3700b	Developmental Toxicity- rabbit (gavage)	45422713 (1998)

45422712 (1998)

range-finding

Acceptable/

guideline

mg/kg/day=0, 10, 25, 75 & 100	Maternal NOAEL = 25 mg/kg/day

Maternal LOAEL = 75 mg/kg/day based on increased incidences of clinical
signs (scant feces and orange urine), mortalities, decreased food
consumption, early delivery, abortion, and decreased body weight gain.

Developmental NOAEL = 25 mg/kg/day

Developmental LOAEL = 75 mg/kg/day based on premature deliveries,
decreased gravid uterine weights, an increased litter incidence of a
missing lobe of the lung, and decreased litter average for ossified
sternal centra per fetus.

870.3800	Reproduction (2- Generation)- rat (diet)	45422715 (2000)

45422714 (2000)

pilot

45422716

(2001)

supplemental

45422825 (1999)

rat feed

45422826

(1999)

rat feed

Acceptable/

guideline

ppm=0, 150, 500 & 2500

mg/kg/day

(M/F)=0/0, 9.8/10.7, 31.2/34.3,163.4/188.8	Parental/Systemic NOAEL =
31.2/36.8 mg/kg/day (M/F)

Parental/Systemic LOAEL = 163.4/188.8 mg/kg/day (M/F) based on decreased
body weight, body weight gain, and absolute and relative thymus weights.

Reproductive NOAEL = 31.2/188.8 mg/kg/day (M/F)

Reproductive LOAEL = 163.4/not established mg/kg/day (M/F) based on
decreased sperm motility and increased number of sperm with detached
heads in both generations.

Offspring NOAEL = 9.8/11.5 mg/kg/day (M/F)

Offspring LOAEL = 31.2/36.8 mg/kg/day (M/F) based on decreased body
weight gains and delayed sexual maturation (M), decreased absolute
thymus weights in F1 pups of both sexes, and an increase in stillbirths
in both generations.

870.4100	Chronic (1 year) - dog (diet)	45422717 (2000)

45422718

Acceptable/

guideline

ppm=0, 325, 650, 1500 & 2000

mg/kg/day (M/F)=0/0,  4.8/8.5, 16.6/15.0, 36.3/40.1, 46.4/52.9	NOAEL =
46.4/40.1 mg/kg/day (M/F)

LOAEL = not established/52.9 mg/kg/day (M/F) based on clinical evidence
of anemia in females.

Note:  dose-related decreases in ALT activity observed in mid- and
high-dose males and females.

870.4200	Carcinogenicity, 18-Month - mouse (diet)	45422721 (2000)

45422709

(1997)

4-week

45422722

(2001)

supplementary

Acceptable/

guideline

ppm=0,100, 350 or 1250

mg/kg/day

(M/F)=0/0, 13.5/17.0, 47.2/65.1, 171.4/215.9

In addition: 50/sex - 700 ppm (wk 1-4), 2000 (5-10), 2500 (11-34),
2000/1800 (M/F) 35-79 [254,1/322,3] 	NOAEL = 171.4/65.1 mg/kg/day (M/F)

LOAEL = 254.1/215.9 mg/kg/day (M/F) based on decreased body weight and
body weight gain; decreased food consumption and food efficiency in
males at the LOAEL. 

No evidence of carcinogenicity.

870.4300	Chronic/ Carcinogenicity, 2-Year-rat (diet) 	45422719 (2000)

45422720

(2001)

supplementary

Acceptable/

guideline

ppm (M/F)=0,  150, 500, 1500 & 3000

mg/kg/day

(M/F)=0/0, 8.1/9.7, 27.4/32.5, 82.0/97.8, 156.5/193.4	NOAEL = 82.0/32.5
mg/kg/day (M/F)

LOAEL = 156.5/97.8 mg/kg/day (M/F) based on decreased body weight and
food consumption and altered hepatocellular eosinophilic focus of the
liver in both sexes; ovary interstitial gland hyperplasia and increased
lymphohistiocytic infiltrate in females; and slightly increased
incidences of pelvic mineralization and transitional cell hyperplasia in
the kidney, mottled livers of males.

No evidence of carcinogenicity.

870.5100

	Gene Mutation bacterial reverse mutation assay

Parent	45422731 (2000)

Acceptable/

guideline	Small, but significant increase in frequency of histidine
revertants in TA 1535 strain treated at 1500 and 5000 µg/plate +/- S9;
still present but weaker in its absence.  The positive response was only
reproducible at 5000 µg/plate +/-S9.  Clothianidin considered mutagenic
under conditions of this test.

870.5100	Gene Mutation bacterial reverse mutation assay

Parent	45422732

(1990)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium and E. coli)
under conditions of this assay.

870.5100	Gene Mutation bacterial reverse mutation assay

Parent	45422733

(1999)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5100	Gene Mutation bacterial reverse mutation assay

Parent	45422734

(1999)

Acceptable/

non-guideline

(only TA 1535 assayed)	Only TA 1535 tested. No mutagenic activity in
bacteria (S. typhimurium) under condtions of this assay. 

870.5100	Gene Mutation bacterial reverse mutation assay

BN0335E2 metabolite	45422724

(2000)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5100	Gene Mutation bacterial reverse mutation assay

TZMU metabolite	45422725

(1999)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5100	Gene Mutation bacterial reverse mutation assay

methyl guanidine intermediate	45422726

(1999)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5100	Gene Mutation bacterial reverse mutation assay

TZNG metabolite	45422727

(1999)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5100	Gene Mutation bacterial reverse mutation assay

TMG metabolite	45422728

(1999)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5100	Gene Mutation bacterial reverse mutation assay

BN0230M metabolite	45422729

(2000)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5100	Gene Mutation bacterial reverse mutation assay

MAI metabolite	45422730

(1999)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5100	Gene Mutation bacterial

reverse mutation assay

N=Methylnitroguanidin intermediate	45422812

(2001)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5100	Gene Mutation bacterial reverse mutation assay

TI 435-Triazan intermediate	45422822

(2000)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5100	Gene Mutation bacterial reverse mutation assay

TI 435-CCMT-Adduct	45422816

(2000)

Acceptable/

guideline	No mutagenic activity in bacteria (S. typhimurium) under
conditions of this assay.

870.5300	Gene Mutation - in vitro mammalian cell gene mutation test
(L5178Y TK +/- mouse lymphoma cells)	45422737 (2000)

Acceptable/

guideline	Increases in mutant frequency with and without S9 at dose
levels that were cytotoxic.  The observed response was primarily due to
small colony formation, indicating clastogenic activity.

870.5300	Gene Mutation - in vitro mammalian cell gene mutation test
(V79-HPRT Assay)	45422738

(1999)

Acceptable/

guideline	No increase in mutant frequency under the conditions of the
study.

870.5300	Gene Mutation – in vitro mammalian cell gene mutation test
(V79 - HPRT Assay)	46339001

(2003)

Acceptable/

guideline	There was no evidence of induced mutant colonies over
background.

870.5375	Cytogenetics - in vitro mammalian chromosome aberration test
(CHL Cells)

Parent	45422736

(2000)

Acceptable/

guideline	Significant increases in frequency of cells with structural
aberrations.  Predominant types were chromatid breaks and exchanges. 
There was, however, no clear indication of a dose-related response in
either the presence or absence of S9 activation.

870.5375	Cytogenetics – in vitro mammalian chromosome aberration test
(CHL Cells)

Parent	46339002

(2003)

Acceptable/

guideline	Clothianidin was clastogenic in the absence of S9 activation
but only at precipitating concentrations.  Some doubt regarding the
relevance of this finding since clastogenicity was abolished when
exogenous metabolic activation was incorporated into the test system and
was confined to precipitating concentrations.

870.5395	Cytogenitics - mammalian erythrocyte micronucleus test

Parent	45422740

(2000)

Acceptable/

guideline	Clothianidin is considered to be neither clastogenic nor
aneugenic under these test conditions.

870.5395	Cytogenetics - mammalian erythrocyte micronucleus test

Parent	46339003

(2003)

Acceptable/

guideline	No significant increase in the frequency of MPCEs in bone
marrow after any harvest in the test groups up to an overtly toxic dose
for this test system.

870.5550	Other Effects - DNA Repair Test in B. subtilis 

Parent	45722735

(1990)

Unacceptable/

non-guideline (only single plates used)	No potential for DNA damage
under these conditions.

870.5500	Other Effects - (UDS) in Mammalian Cells in Culture

Parent	45422739

(1999)

Acceptable/

non-guideline

(only males used)	No evidence (or a dose related positive response) that
UDS was induced.

870.6200a

	Acute Neurotoxicity Screening Battery-rat (gavage)	45422801

 (2000)

45422802

(2000)

to establish NOEL

Acceptable/

guideline

mg/kg=0,100, 200 & 400

NOEL=0, 20, 40 & 60	NOAEL = 60 mg/kg

LOAEL = 100 mg/kg based on FOB findings (decreased arousal, motor
activity, and locomotor activity).

870.6200b

	Subchronic Neurotoxicity Study-rat (diet)	45422803 (2000)

45422825

(1999)

supplementary

Acceptable/

guideline

ppm (M/F)=0, 150, 1000 & 3000

mg/kg/day

(M/F)=0/0,9.2/10.6, 60.0/71.0, 177.0/200.1	NOAEL = 60.0/71.0 mg/kg/day
(M/F)

LOAEL = 177.0/200.1 mg/kg/day (M/F) based on slightly decreased food
consumption, body weights, and body weight gains.

No evidence of neurotoxicity.

870.6300

	Developmental Neurotoxicity Study-rat

(diet)	445422804

(2000)

Acceptable/

non-guideline

(upgradable with FOB information)

ppm=0, 150, 500 & 1750

mg/kg/day

gestation=0, 12.9, 42.9, 142

lactation=0, 27.3, 90.0, 299.0	Maternal NOAEL = 42.9 mg/kg/day

Maternal LOAEL = 142 mg/kg/day based on decreased body weights, body
weight gains, and food consumption.

Offspring NOAEL = 12.9 mg/kg/day

Offspring LOAEL = 42.9 mg/kg/day based on decreased body weights, body
weight gains, motor activity, and acoustic startle response in females.

870.7485	Metabolism Study- rat

	45422805 (2000)

45422806

 (2000)

Acceptable/

guideline

single dose=2.5 or 250mg/kg;

14-day repeated dose =25 mg/kg/day	Overall recovery: 95-100%. Readily
absorbed and excreted within 96 hours following a single 2.5 mg/kg bw or
repeated oral dose of 25 mg/kg bw, but at a dose of 250 mg/kg,
absorption became biphasic and was saturated.  Following single or
multiple oral low doses (2.5 and 25mg/kg bw, respectively) of
clothianidin, urinary excretion accounted for 89.2-94.6% of the
administered radioactivity suggesting that a multiple exposure regimen
did not affect the absorption/excretion processes.  Urinary excretion
unaffected following single 250 mg/kg dose.  Excretion via the feces
accounted for the remainder of the administered radioactivity in all
treatment groups (3.8-8.6%). Rapid absorption and distribution of
administered radioactivity to all organs and tissues followed by rapid
excretion with reduction to background levels in most tissues and organs
within 24 hours. Somewhat greater rate of absorption and elimination in
females.  Excretory patterns did not exhibit gender-related variability
but reflected the delayed absorption in the high-dose group.  Neither
clothianidin nor metabolites appear to undergo significant
sequestration. 

 The metabolites identified (primarily oxidative demethylation products
and cleavage products of the nitrogen-carbon bond between the nitroimino
and thiazolyl moieties) were consistent with Phase I processes. 
Extraction efficiencies appeared to be excellent and most components in
all of the matrices examined (urine, feces, and tissues) were adequately
quantified and characterized.  The available data, based upon studies
using both the nitroimino- and the thiazolyl-2-labeled clothianidin,
affirmed the metabolism pathway proposed by the investigators.

870.7485	Metabolism Study – mice

	45422807

(2000)

Acceptable/

non-guideline

single gavage dose of 5 mg/kg	Of the administered radioactivity,
98.7-99.2% was recovered. Readily absorbed and excreted within 168 hours
following a single oral dose of 5 mg/kg body weight.  Urine was the
major route of excretion, accounting for 92.4-93.7% of the administered
radioactivity. Feces accounted for 5.0-6.8% of the administered
radioactivity.  Within 24 hours, 89.0-91.7 % of the administered
radioactivity was excreted in the urine and 4.9-6.2% was excreted in the
feces.  Residual radioactivity in any given tissue at 168 hours
post-dose was considerably less than 1% of the administered dose. 
Therefore, neither clothianidin nor its metabolites appeared to exhibit
potential for bioaccumulation. Excretory patterns did not exhibit
gender-related variability.

(2-chlorothiazol-5-ylmethyl)-N-nitroguanidine] which resulted from
N-demethylation of clothianidin.  Extraction efficiencies were excellent
and most components in the urine and feces were adequately quantified
and characterized.  Based on the data from the oral administration of
[nitroimino-14C]-clothianidin the metabolism pathway proposed by the
investigators was supported.

870.7600	Dermal Penetration – 

monkey	45868001 (2003)

Acceptable/

non-guideline

6.13 µg/cm2

8 hour exposure

	Dermal absorption as the sum of urinary and fecal excretion and
Cage/Pan/Chair Wash, Debris was 0.24 (+ 0.11) as percent of dose.
Adjustment of the direct absorption determination was not necessary
because recovery from the dermal dose was >90%.  

A value of 1% dermal absorption was considered appropriate for use in
risk assessment.  This estimation takes into account any variability
that would have likely occurred with testing several dose levels.

870.7800	Immunotoxicity–rat (adult) (diet)	46536502

(2004)

Acceptable/

guideline

ppm=0, 150, 500 & 3000

mg/kg/day

(M/F)=0/0, 13.8/14.0, 45.8/46.2, 252.8/253	Immunotoxicity NOAEL = 253
mg/kg/day (M&F)

Immunotoxicity LOAEL = not established

At the highest dose tested, 253 mg/kg/day, a decrease in body weights,
body weight gains and food consumption were noted in adult males and
females.

Non-guideline	Developmental Immunotoxicity study - rat

(diet)	47526501 (2008)

Acceptable/

non-guideline

ppm=0, 150, 500 & 2000

mg/kg/day

gestation=0, 10, 35, 121

lactation=0, 22, 68, 250

after weaning:

Assay 1=0/0, 28/26, 98/93,404/404

Assay 2=0/0, 28/27, 89/93, 338/398	No immunotoxicological adverse
effects at any of the doses tested.

Non-guideline	Other Genotoxicity – Unscheduled DNA synthesis in
primary rat hepatocytes	46339004

(2003)

Acceptable/

non-guideline	No evidence of DNA damage and repair in this test system,
as determined by radioactive tracer procedures (nuclear silver grain
counts).

Non-guideline	Special Study:

Neurotoxicity and pharmacology - mouse	445422823

(2000)

Acceptable/

non-guideline

mg/kg=0, 12.5, 25, 50, 100, 200, 400 (single gavage dose)	NOAEL = 25
mg/kg/day (M/F)

LOAEL = 50 mg/kg (M/F) based on transient signs of decreased spontaneous
motor activity, tremors and deep respirations.



A3.	Toxicology Executive Summaries TC \l2 "A3.	Toxicology Executive
Summaries 

STUDY TYPE: 	Developmental Immunotoxicity Study in Rats (diet) -
Non-guideline

PC CODE:  044309	DP BARCODE:  D356839

TXR #:  0054981	SUBMISSION:  S835361

TEST MATERIAL (PURITY):  Clothianidin (95.2% a.i.)

N′-methyl-N″-nitroguanidine

CITATION:	Hoberman, A.M. (2008).  Oral (diet) developmental
immunotoxicity study of TI 435 (clothianidin) in Crl: CD(SD) rats. 
Charles River Laboratories, Preclinical Services, Horsham, PA. 
Laboratory Study no.:  5819-008, August 6, 2008.  MRID 47526501. 
Unpublished.

SPONSOR:	Sumitomo Chemical Company, Ltd., 27-1, Shinkawa 2-chome,
Chuo-ku, Tokyo, Japan

EXECUTIVE SUMMARY:  In a non-guideline developmental immunotoxicity
study (MRID 47526501), 25 presumed pregnant Sprague-Dawley rats/dose
group were dosed with Clothianidin (95.2% a.i.; batch no. 30037120) in
acetone as dietary admixtures at doses of 0, 150, 500, or 2000 ppm. 
These doses corresponded, respectively, to doses of 0, 10, 35, or 121
mg/kg/day for gestation day (GD) 6-20 and 0, 22, 68, or 250 mg/kg/day
for lactation day (LD) 0-13. After weaning (PND 22 to 36), F1-generation
rats were offered the dietary formulations at the same concentrations as
their parents and the corresponded doses were 0, 28/26, 98/93, or
404/404 mg/kg/day for males/females in Assay 1 and 0, 28/27, 89/93, or
338/398 mg/kg/day for males/females in Assay 2, respectively. Prior to
PND 21, the F1-generation were potentially exposed through the maternal
milk and inadvertently to the dam’s dose formulation after
approximately PND 13.  Following weaning, one pup/sex/litter was
selected to continue on study when possible.  Two to three
weanlings/sex/dose were evaluated for the following parameters: 
mortality, body weight, body weight gain, food consumption, and gross
pathology (sacrificed at approximately 7 weeks).  The remaining
weanlings were assigned to immunoassays.

Weanlings assigned to Assay 1 (antibody-forming-cell assay) were
sensitized by intravenous injection of 0.5 ml of sheep erythrocytes
(SRBCs) 4 days before sacrifice. Rats were sacrificed at 41±5 days of
age and the thymus and spleen were excised and weighed. The primary IgM
anti-SRBC antibody-forming-cell responses were determined.  Weanlings
assigned to Assay 2 (delayed-type hypersensitivity, DTH) were sensitized
by subcutaneous injection of 0.2 ml Candida albicans formalin fixed
cells in their right flank 8 days before being challenged with 100 µl
injection of Candida albicans chitosan antigen into the foot pad. 
Swelling of the footpads, due to DTH response, was measured with a
micrometer prior to challenge and 24 and 48 hours after the challenge. A
challenge-only control group was used to correct for trauma associated
with the challenge injection. Cycloposphamide (CPS) served as a positive
control.  CPS was administered at a dose of 50 mg/kg (10 mg/mL) in
phosphate buffered saline by daily intraperitoneal injection on the last
4 days of exposure for Assay 1 and on the last 4 days before challenge
for Assay 2.

For maternal toxicity, no treatment-related effects were observed on
mortality or gross pathology in the dams. At 2000 ppm in the dams, an
increased incidence of ptosis was observed in 6 animals for a total of
16 observations compared to 0 animals in the other groups. At 2000 ppm,
the body weights were generally decreased during GD 9-20 by 3-6% and
during LD 0-21 by 3-11%.  Body weights gains were decreased during GD
6-9 by 71% and during GD 18-20 by 25%.  These effects contributed to a
decreased body weight gain of 21% for the overall (GD 6-20) treatment
interval and a decreased body weight gain in the overall (GD 0-20)
gestational period of 14%.  During the lactation period a weight loss
was noted during LD 0-3 (-8.0 g) compared to controls (4.6 g), and body
weight gain remained decreased for LD 3-6 by 58%.  Food consumption was
decreased during the overall treatment, gestational, and lactation
periods.  

The maternal LOAEL is 2000 ppm, based on increased incidence of ptosis,
and decreased body weights and body weight gain, and food consumption. 
The maternal NOAEL is 500 ppm.

ion (↓7-29%), and bodyweight gain from PND 22 until termination was
decreased (p≤0.01) by 24-25% in males and 15-17% in females. Food
consumption was decreased for PND 22-29, 29-36, and 22-36 by 19-34%.

The offspring LOAEL is 2000 ppm, based on a decreased body weights, body
weight gains, and food consumption.  The offspring NOAEL is 500 ppm.

For immune function evaluation, there were statistically significant
decreases in thymus and spleen weight in the F1 weanlings at 2000 ppm
for males and females. These decreases might be related to significant
decreases of body weights at the high dose and was considered secondary
effect to general systemic toxicity and not direct immunological
toxicity.

(p≤0.05) in spleen specific activity (AFC/106 spleen cells, ↑143%)
and total spleen activity (AFC/Spleen, ↑99%) at 2000 ppm.  However,
individual animal data showed that the majority of animals in this group
showed similar response compared with other treated and control groups
except 3 females in the 2000 ppm that had higher specific activity and
total spleen activity than the median response of this group that
resulted in the statistically significant increased activities of this
group compared to the controls. The variability of immune response was
commonly observed in the outbred SD rats. Therefore, the statistical
significance may not be biologically significant considering with
distribution pattern of the responses. The positive control induced the
expected response that produced significant decreases in total spleen
cell number, specific activity and total spleen activity compared with
the control.

For cell-mediated immunity, delayed-type hypersensitivity (DTH) assay
did not show treatment-related effect at any treated dose at both 24 and
48 hours in this assay for males and females. The positive control
showed the expected response of significantly suppressive responses at
24 hour and 48 hour post-challenge.  

	

Under conditions of this study, there were no immunologically adverse
effects on humoral or cell-mediated immunity in male and female rats
that exposed to clothianidin during the prenatal, postnatal and
post-weaning period.

This study is classified acceptable/non-guideline and provides
information for use in evaluating the potential for immunotoxic effect
in offspring rats after exposure to clothianidin during the prenatal,
postnatal and post-weaning period.

STUDY TYPE:  Other Genotoxicity: Unscheduled DNA Synthesis in Primary
Rat Hepatocytes from Treated Rats [No Guideline]

DPBARCODE: DP309210

PC CODE: 044309  

TEST MATERIAL (PURITY): TI-435 (96.4% a.i/ Batch No.LOT30037120)

SYNONYMS: Clothianidin  

CITATION:	Honarvar, N. (2003).  In vivo/in vitro unscheduled DNA
synthesis in rat hepatocytes with TI-435. RCC – Cytotest Cell Research
GmbH, Rossdorf, Germany. Laboratory Project ID: 802504, December 9,
2003.   MRID 46339004. Unpublished.

SPONSOR:	Sumitomo Chemical Takeda Agro Co Ltd., Tokyo, Japan

EXECUTIVE SUMMARY:  In an in vitro/in vivo unscheduled DNA synthesis
assay (MRID 46339004), groups of Wistar male rats (4/group) were
administered TI-435 (96.4% a.i/ Batch No.LOT30037120) in 0.5% Cremophor
at doses of 0, 1000 or 2000 mg/kg.  Hepatocytes were isolated from 3
animals in each treatment, vehicle or positive
[N,N’dimethylhydrazine-dihydroxhloride (DMH) and 2-acetylaminofluorene
(2-AAF)] control groups at 2 and 16 hours.  Recovered cells were allowed
to attach to coverslips, placed in tridiated thymidine, and prepared for
autoradiographs.  Unscheduled DNA synthesis (UDS) was determined by
comparing radioactive labeling in hepatocyte nuclei from animals treated
with TI-435 to cells recovered from the vehicle control group.  

Signs of toxicity similar to those seen in the preliminary study,
performed in male and female rats with 2000 mg/kg of the test material,
were observed in the main assay for both treatment groups up to
sacrifice.  Females were not tested in the main assay because there was
no evidence of a toxicological difference among the sexes in the
preliminary study.  There was also no evidence of a cytotoxic effect on
the harvested hepatocytes.  Results for the 2- and 16-hour harvests
indicated that the test material did not adversely affect DNA since
animals did not manifest any increases in either the gross nuclear grain
counts, (gross nuclear grain counts minus cytoplasmic grain counts) at
any dose or sacrifice time.  By contrast, positive control groups showed
significant marked increases in the NNGC compared to the vehicle control
group. Therefore, TI-435 has shown no evidence of DNA damage and repair
in this test system, as determined by radioactive tracer procedures
(nuclear silver grain counts).

This study is classified as acceptable.  As yet, there is no FIFRA Test
Guideline for this type of in vivo study. 

STUDY TYPE: 	In Vivo Mammalian Cytogenetics - Erythrocyte Micronucleus
Assay in Mice; OPPTS 870.5395 [(84-2]; OECD 474.

PC CODE: 044309	DP BARCODE: DP309210 

TEST MATERIAL (PURITY): TI-435 (96.4% a.i/ Batch No.LOT30037120)

SYNONYMS: Clothianidin  

CITATION:	Honarvar, N. (2003).  TI-435 Micronucleus Assay in Bone Marrow
Cells of the Mouse. RCC – Cytotest Cell Research GmbH, Rossdorf,
Germany. Laboratory Project ID: 802503, December 9, 2003.   MRID
46339003. Unpublished.

SPONSOR:	Sumitomo Chemical Takeda Agro Co Ltd., Tokyo, Japan

EXECUTIVE SUMMARY - In a bone marrow micronucleus assay (MRID 46339003),
adult male and female NMRI mice (5/dose/sex in vehicle, positive or dose
group of the test material) were treated once via oral gavage with 0,
50, 100 or 200 mg/kg of TI-435 (96.4% a.i./ Batch No.LOT30037120)
prepared in 0.5% Cremophor.  Bone marrow cells were harvested at 24
hours for all treatment groups and an additional group administered the
high dose was sacrificed at 48 hours following dosing.  Cells were
examined for the frequency of micronucleated polychromatic erythrocytes
(MPCEs) from the count of 2000 PCEs/animal.  

Deaths at 1000 mg/kg and clinical signs of toxicity (reduced spontaneous
activity, abdominal position, eye closure, and ruffled fur) at ≥100
mg/kg in males and females were noted in the preliminary test evaluating
a dose range of 100 to 1000 mg/kg in either sex.  Accordingly, 200 mg/kg
was selected as the maximum tolerated dose (MTD) for the cytogenetic
assay.  In general, similar signs (i.e., reduced spontaneous activity,
abdominal position, eye closure, and ruffled fur) were noted at 200
mg/kg in males and females for the first 6 hours of treatment and
diminished, thereafter.  There was, however, no evidence of a cytotoxic
effect on the bone marrow at any dose. The positive control induced the
appropriate response.  There was no significant increase in the
frequency of MPCEs in bone marrow after any harvest in the test groups
up to an overtly toxic dose for this test system.

This study is classified as acceptable/guideline and satisfies the
guideline requirement for Test Guideline OPPTS 870.5395; OECD 474 for in
vivo cytogenetic mutagenicity data.

STUDY TYPE:	In Vitro Mammalian Cells in Culture Gene Mutation assay in
V79 Chinese hamster cells; OPPTS 870.5300 [§84-2]; OECD 476.

PC CODE:  044309									                     DP BARCODE:  D309210

TEST MATERIAL (PURITY TI-435 (96.4% a.i./Batch No. Lot 300037120)

SYNONYMS:  Chlothianidin

CITATION: 	Poth, A.P. (2003). Gene Mutation Assay in Chinese Hamster V79
Cells In Vitro (V79/HPRT) with TI-435.  RCC-Cytotest Cell Research GmbH,
Rossdorf, Germany, Study No. 802501.  December 9, 2003. MRID 46339001.
Unpublished.

SPONSOR:	Sumitomo Chemical Takeda Agro Co. Ltd. Tokyo, Japan

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萏֠萑褐葞֠葠褐摧潚Õഀe S9-mix was obtained from
Phenobarbital/β-Naphthoflavone induced male Wistar rat liver.

TI-435 was tested up to the solubility limit (≥1250 µg/mL –S9 and
2500 µg/mL +S9).  Cytotoxicity as indicated by a strong decrease in
relative cloning efficiency (CE) was observed at 1250 µg/mL (-S9) in
Experiment 1 and ≥ 500 µg/mL in Experiment 2, with an mean relative
CE of ≤ 10%.  Little or no cytotoxicity was observed in the presence
of S9 mix (relative CE ≥ 90%).   A slightly greater than 3-fold
increase in MF was observed in Exp. 1 at 2500 µg/mL (-S9, trial 1) and
at 1250 µg/mL (-S9, trial 2) and in Exp. 2 at 1000 µg/mL (-S9, trial
2). However; these increases were neither reproducible, nor
concentration-related and occurred at concentrations that exhibited
severe cytotoxicity (relative CE <13%).  The MFs per 106 surviving cells
for the solvent controls for the two trials (Exp.1) with S9 were 7.7 and
4.0, respectively.  No increase in MF was observed at any concentration
in the presence of S9. The number of mutant colonies per 106 colonies
for solvent and positive controls with and without metabolic activation
fell within their respective historical control ranges for the testing
laboratory.

The positive controls did induce the appropriate responses.  There was
no evidence of induced mutant colonies over background.

This study is classified as Acceptable/Guideline and satisfies the
guideline requirement for Test Guideline OPPTS 870.5300, OECD 476 for in
vitro mutagenicity (mammalian forward gene mutation) data.

STUDY TYPE:	In vitro Mammalian Cytogenetics Assay.

PC CODE:  044309	DP BARCODE:  DP309210

	

TEST MATERIAL (PURITY): TI-435 (96.4% a.i/ Batch No.LOT30037120)

SYNONYMS: Clothianidin  

CITATION:	Schultz, M. (2003).  In vitro chromosome aberration test in
Chinese hamster V79 Cells with TI-435.  RCC – Cytotest Cell Research
GmbH, Rossdorf, Germany. Laboratory Project ID: 802502, December 9,
2003.   MRID 46339002. Unpublished.

SPONSOR:	Sumitomo Chemical Takeda Agro Co Ltd., Tokyo, Japan

EXECUTIVE SUMMARY:

In a mammalian cell cytogenetics assay (chromosome aberration) (MRID
46339002), Chinese hamster V79 cultures were exposed to TI-435 (96.4%
a.i/ Batch No.LOT30037120)

prepared in dimethyl sulfoxide (DMSO) at concentrations of 0, 750, 1000,
1500 and 2000 (g/mL without metabolic activation for 4 hours and
harvested at 18 hours.  In the presence of S9 activation, cells were
treated with of 0,500, 750 or 1000 (g/mL for 4 hours and harvested at 18
 hours. The S9 fraction was derived from the livers of male Wistar Han
rats induced with phenobarbitone/(-naphthoflavone and scored for
structural chromosome aberrations.  Ethyl methane sulfonate (EMS) and
cyclophosphamide (CP) served as positive controls in the absence and
presence of S9, respectively.

TI-435 was tested up to precipitating concentrations (≥ 1500 µg/mL
–S9; ≥ 750µg/mL +S9) but was not appreciably cytotoxic (generally
≥ 50% reduction in the mitotic index). Significant (p<0.001) and
biologically relevant increases were seen at 1500 and 2000 µg/mL – S9
(8.0 and 24 % aberrant cells, respectively (minus gaps).  The most
prominent types of aberrations were chromatid breaks, fragments and
exchanges. The response was abolished in the presence of S9 activation. 
No appreciable increase in numerical aberrations was seen at any
nonactivated or S9-activted treatment group.   Both positive controls
(EMS at 200 µg/mL – S9 and 0.7 µg/mL + S9) induced significant
(p<0.001) increases in the percentage of cells with aberrations.  The
solvent and positive control values induced the expected responses.  It
was concluded, therefore, that TI-435 was clastogenic in the absence of
S9 activation but only at precipitating concentrations.   There is,
however, some doubt regarding the relevance of this finding since
clastogenicity was abolished when exogenous metabolic activation was
incorporated into the test system and was confined to precipitating
concentrations. 

This study is classified as Acceptable/Guideline and satisfies the
guideline requirement for In vitro mammalian cytogenetics (chromosome
aberrations) OPPTS 870.5375; OECD 473.

 TZMU = N-(2-Chlorothiazol-5-ylmethyl)-N’-methylurea

TZNG = N-(2-Chloro-5-thiazolylmethyl)-N’-nitroguanidine

THMN = Thiazolyl hydroxy methyl nitroguanidine

TZU = N-(2-Chlorothiazol-5-ylmethyl) urea

TMG = N-(2-Chloro-5-thiazolylmethyl)-N’-methylguanidine

MNG = N-Methyl-N’-nitroguanidine

MG = Methyl guanidine

NTG = Nitroguanidine

ATMG-Pyruvate =
N’-[(2-chlorothiazol-5-ylmethylamino)(methylamino)methylene]-2-oxoprop
ano hydrazide

ATG-Acetate = N’-[amino(2-chlorothiazol-5-ylmethylamino)methylene]
acetohydrazide

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