[Federal Register Volume 69, Number 106 (Wednesday, June 2, 2004)]
[Notices]
[Pages 31110-31116]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-12311]


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ENVIRONMENTAL PROTECTION AGENCY

[OPP-2004-0185; FRL-7361-1]


Thiamethoxam; Notice of Filing a Pesticide Petition to Establish 
a Tolerance for a Certain Pesticide Chemical in or on Food

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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SUMMARY: This notice announces the initial filing of a pesticide 
petition proposing the establishment of regulations for residues of a 
certain pesticide chemical in or on various food commodities.

DATES: Comments, identified by docket ID number OPP-2004-0185, must be 
received on or before July 2, 2004.

ADDRESSES: Comments may be submitted electronically, by mail, or 
through hand delivery/courier. Follow the detailed instructions as 
provided in Unit I. of the SUPPLEMENTARY INFORMATION.

FOR FURTHER INFORMATION CONTACT: Dani Daniel, Registration Division 
(7505C), Office of Pesticide Programs, Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 305-5409; e-mail address:[email protected].

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be potentially affected by this action if you are an 
agricultural producer, food manufacturer, or pesticide manufacturer. 
Potentially affected entities may include, but are not limited to:
     Crop production (NAICS 111)
     Animal production (NAICS 112)
     Food Manufacturing (NAICS 311)
     Pesticide manufacturing (NAICS 32532)
    This listing is not intended to be exhaustive, but rather provides 
a guide for readers regarding entities likely to be affected by this 
action. Other types of entities not listed in this unit could also be 
affected. The North American Industrial Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether this action might apply to certain entities. If you have any 
questions regarding the applicability of this action to a particular 
entity, consult the person listed under FOR FURTHER INFORMATION 
CONTACT.

B. How Can I Get Copies of this Document and Other Related Information?

    1. Docket. EPA has established an official public docket for this 
action under docket identification (ID) number OPP-2004-0185. The 
official public docket consists of the documents specifically 
referenced in this action, any public comments received, and other 
information related to this action. Although a part of the official 
docket, the public docket does not include Confidential Business 
Information (CBI) or other information whose disclosure is restricted 
by statute. The official public docket is the collection of materials 
that is available for public viewing at the Public Information and 
Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall 2, 
1921 Jefferson Davis Hwy., Arlington, VA. This docket facility is open 
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal 
holidays. The docket telephone number is (703) 305-5805.
    2. Electronic access. You may access this Federal Register document 
electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr/.
    An electronic version of the public docket is available through 
EPA's electronic public docket and comment system, EPA Dockets. You may 
use EPA Dockets at http://www.epa.gov/edocket/ to submit or view public 
comments, access the index listing of the contents of the official 
public docket, and to access those documents in the public docket that 
are available electronically. Although not all docket materials may be 
available electronically, you may still access any of the publicly 
available docket materials through the docket facility identified in 
Unit I.B.1. Once in the system, select ``search,'' then key in the 
appropriate docket ID number.
    Certain types of information will not be placed in the EPA Dockets. 
Information claimed as CBI and other information whose disclosure is 
restricted by statute, which is not included in the official public 
docket, will not be available for public viewing in EPA's electronic 
public docket. EPA's policy is that copyrighted material will not be 
placed in EPA's electronic public docket but will be available only in 
printed, paper form in the official public docket. To the extent 
feasible, publicly available docket materials will be made available in 
EPA's electronic public docket. When a document is selected from the 
index list in EPA Dockets, the system will identify whether the 
document is available for viewing in EPA's electronic public docket. 
Although not all docket materials may be available electronically, you 
may still access any of the publicly available docket materials through 
the docket facility identified in Unit I.B. EPA intends to work towards 
providing electronic access to all of the publicly available docket 
materials through EPA's electronic public docket.
    For public commenters, it is important to note that EPA's policy is 
that public comments, whether

[[Page 31111]]

submitted electronically or in paper, will be made available for public 
viewing in EPA's electronic public docket as EPA receives them and 
without change, unless the comment contains copyrighted material, CBI, 
or other information whose disclosure is restricted by statute. When 
EPA identifies a comment containing copyrighted material, EPA will 
provide a reference to that material in the version of the comment that 
is placed in EPA's electronic public docket. The entire printed 
comment, including the copyrighted material, will be available in the 
public docket.
    Public comments submitted on computer disks that are mailed or 
delivered to the docket will be transferred to EPA's electronic public 
docket. Public comments that are mailed or delivered to the docket will 
be scanned and placed in EPA's electronic public docket. Where 
practical, physical objects will be photographed, and the photograph 
will be placed in EPA's electronic public docket along with a brief 
description written by the docket staff.

C. How and To Whom Do I Submit Comments?

    You may submit comments electronically, by mail, or through hand 
delivery/courier. To ensure proper receipt by EPA, identify the 
appropriate docket ID number in the subject line on the first page of 
your comment. Please ensure that your comments are submitted within the 
specified comment period. Comments received after the close of the 
comment period will be marked ``late.'' EPA is not required to consider 
these late comments. If you wish to submit CBI or information that is 
otherwise protected by statute, please follow the instructions in Unit 
I.D. Do not use EPA Dockets or e-mail to submit CBI or information 
protected by statute.
    1. Electronically. If you submit an electronic comment as 
prescribed in this unit, EPA recommends that you include your name, 
mailing address, and an e-mail address or other contact information in 
the body of your comment. Also include this contact information on the 
outside of any disk or CD ROM you submit, and in any cover letter 
accompanying the disk or CD ROM. This ensures that you can be 
identified as the submitter of the comment and allows EPA to contact 
you in case EPA cannot read your comment due to technical difficulties 
or needs further information on the substance of your comment. EPA's 
policy is that EPA will not edit your comment, and any identifying or 
contact information provided in the body of a comment will be included 
as part of the comment that is placed in the official public docket, 
and made available in EPA's electronic public docket. If EPA cannot 
read your comment due to technical difficulties and cannot contact you 
for clarification, EPA may not be able to consider your comment.
    i. EPA Dockets. Your use of EPA's electronic public docket to 
submit comments to EPA electronically is EPA's preferred method for 
receiving comments. Go directly to EPA Dockets at http://www.epa.gov/edocket/, and follow the online instructions for submitting comments. 
Once in the system, select ``search,'' and then key in docket ID number 
OPP-2004-0185. The system is an``anonymous access'' system, which means 
EPA will not know your identity, e-mail address, or other contact 
information unless you provide it in the body of your comment.
    ii. E-mail. Comments may be sent by e-mail to [email protected], 
Attention: Docket ID Number OPP-2004-0185. In contrast to EPA's 
electronic public docket, EPA's e-mail system is not an ``anonymous 
access'' system. If you send an e-mail comment directly to the docket 
without going through EPA's electronic public docket, EPA's e-mail 
system automatically captures your e-mail address. E-mail addresses 
that are automatically captured by EPA's e-mail system are included as 
part of the comment that is placed in the official public docket, and 
made available in EPA's electronic public docket.
    iii. Disk or CD ROM. You may submit comments on a disk or CD ROM 
that you mail to the mailing address identified in Unit I.C.2. These 
electronic submissions will be accepted in WordPerfect or ASCII file 
format. Avoid the use of special characters and any form of encryption.
    2. By mail. Send your comments to: Public Information and Records 
Integrity Branch (PIRIB) (7502C), Office of Pesticide Programs (OPP), 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460-0001, Attention: Docket ID Number OPP-2004-0185.
    3. By hand delivery or courier. Deliver your comments to: Public 
Information and Records Integrity Branch (PIRIB), Office of Pesticide 
Programs (OPP), Environmental Protection Agency, Rm. 119, Crystal Mall 
2, 1921 Jefferson Davis Hwy., Arlington, VA, Attention: Docket 
ID Number OPP-2004-0185. Such deliveries are only accepted during the 
docket's normal hours of operation as identified in Unit I.B.1.

D. How Should I Submit CBI to the Agency?

    Do not submit information that you consider to be CBI 
electronically through EPA's electronic public docket or by e-mail. You 
may claim information that you submit to EPA as CBI by marking any part 
or all of that information as CBI (if you submit CBI on disk or CD ROM, 
mark the outside of the disk or CD ROM as CBI and then identify 
electronically within the disk or CD ROM the specific information that 
is CBI). Information so marked will not be disclosed except in 
accordance with procedures set forth in 40 CFR part 2.
    In addition to one complete version of the comment that includes 
any information claimed as CBI, a copy of the comment that does not 
contain the information claimed as CBI must be submitted for inclusion 
in the public docket and EPA's electronic public docket. If you submit 
the copy that does not contain CBI on disk or CD ROM, mark the outside 
of the disk or CD ROM clearly that it does not contain CBI. Information 
not marked as CBI will be included in the public docket and EPA's 
electronic public docket without prior notice. If you have any 
questions about CBI or the procedures for claiming CBI, please consult 
the person listed under FOR FURTHER INFORMATION CONTACT.

E. What Should I Consider as I Prepare My Comments for EPA?

    You may find the following suggestions helpful for preparing your 
comments:
    1. Explain your views as clearly as possible.
    2. Describe any assumptions that you used.
    3. Provide copies of any technical information and/or data you used 
that support your views.
    4. If you estimate potential burden or costs, explain how you 
arrived at the estimate that you provide.
    5. Provide specific examples to illustrate your concerns.
    6. Make sure to submit your comments by the deadline in this 
notice.
    7. To ensure proper receipt by EPA, be sure to identify the docket 
ID number assigned to this action in the subject line on the first page 
of your response. You may also provide the name, date, and Federal 
Register citation.

II. What Action is the Agency Taking?

    EPA has received a pesticide petition as follows proposing the 
establishment and/or amendment of regulations for residues of a certain 
pesticide chemical in or on various food commodities

[[Page 31112]]

under section 408 of the Federal Food, Drug, and Cosmetic Act (FFDCA), 
21 U.S.C. 346a. EPA has determined that this petition contains data or 
information regarding theelements set forth in FFDCA section 408(d)(2); 
however, EPA has not fully evaluated the sufficiency of the submitted 
data at this time or whether the data support granting of the petition. 
Additional data may be needed before EPA rules on the petition.

List of Subjects

    Environmental protection, Agricultural commodities, Feed additives, 
Food additives,Pesticides and pests, Reporting and recordkeeping 
requirements.

    Dated: May 24, 2004.
Lois Rossi,
Director, Registration Division, Office of Pesticide Programs.

Summary of Petition

    The petitioner summary of the pesticide petition is printed below 
as required by FFDCA section 408(d)(3). The summary of the petition was 
prepared by the petitioner and represents the view of the petitioner. 
The petition summary announces the availability of a description of the 
analytical methods available to EPA for the detection and measurement 
of the pesticide chemicalresidues or an explanation of why no such 
method is needed.

Syngenta Crop Protection Inc. and Interregional Research Project 
4

PP 2E6363, 3E6781, 3E6800, 3E6806, 3E6805, 3E6807, 4E6819, 9F5051 and 
0F6142

    EPA has received pesticide petitions (PP 2E6363, 3E6781, 3E6800, 
3E6806, 3E6805, 3E6807, 4E6819, 9F5051 and 0F6142) from Syngenta Crop 
Protection Inc., P.O. Box 18300, Greensboro, NC 27419-8300 and 
Interregional Research Project 4 (IR-4), 681 US Highway 
1 South, North Brunswick, NJ 08902-3390, proposing, pursuant 
to section 408(d) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 
21 U.S.C. 346a(d), to amend 40 CFR part 180 by establishing tolerances 
for residues of thiamethoxam [3-[(2-chloro-5-
thiazolyl)methyl]tetrahydro-5-methyl-N-nitro-4H-1,3,5-oxadiazin-4-
imine] (CAS Reg. No. 153719-23-4) and its metabolite [N-(2-chloro-
thiazol-5-ylmethyl)-N'-methyl-N''-nitro-guanidine) in or on the raw 
agricultural commodities peppermint and spearmint, tops at 4.0 parts 
per million (ppm); legume vegetables (succulent or dried) at 0.02 ppm; 
root vegetables (except sugar beet) crop subgroup (1b) at 0.10 ppm and 
for radish tops at 0.80 ppm; strawberry at 0.30 ppm; cranberry at 0.01 
ppm; bushberry crop subgroup (13B) and juneberry, lingonberry and salal 
at 0.25 ppm; rapeseed, seed; Indian rapeseed; Indian mustard, seed; 
field mustard, seed; black mustard, seed; flax, seed; safflower, seed; 
crambe, seed; and borage, seed at 0.02 ppm; grapes at 0.15 ppm; grape 
juice at 0.20 ppm and raisins at 0.30 ppm; a tolerance increase for 
tuberous and corm crop subgroup (1C) from 0.02 ppm to 0.25 ppm; leafy 
vegetables (except brassica vegetables) at 2.0 ppm; leafy brassica 
greens crop subgroup 5B at 2.0 ppm; and head and stem brassica crop 
subgroup 5A at 1.0 ppm. EPA has determined that the petition contains 
data or information regarding the elements set forth in section 
408(d)(2) of the FFDCA; however, EPA has not fully evaluated the 
sufficiency of the submitted data at this time or whether the data 
supports granting of the petition. Additional data may be needed before 
EPA rules on the petition.

A. Residue Chemistry

    1. Plant metabolism. The primary metabolic pathways of thiamethoxam 
in plants (corn, rice, pears, and cucumbers) were similar to those 
described for animals, with certain extensions of the pathway in 
plants. Parent compound and CGA-322704 were the major residues in all 
crops. The metabolism of thiamethoxam in plants and animals is 
understood for the purposes of the proposed tolerances. Parent 
thiamethoxam and the metabolite, CGA-322704, are the residues of 
concern for tolerance setting purposes.
    2. Analytical method. Syngenta Crop Protection Inc. has submitted 
practical analytical methodology for detecting and measuring levels of 
thiamethoxam in or on raw agricultural commodities. The method is based 
on crop specific cleanup procedures and determination by liquid 
chromatography with either ultraviolet (UV) or mass spectrometry (MS) 
detection. The limit of detection (LOD) for each analyte of this method 
is 1.25 ng injected for samples analyzed by UV and 0.25 ng injected for 
samples analyzed by MS, and the limit of quantitation (LOQ) is 0.005 
ppm for milk and juices and 0.01 ppm for all other substrates.
    3. Magnitude of residues. IR-4 has submitted complete residue data 
for thiamethoxam on peppermint and spearmint tops; legume vegetables; 
root and tuber vegetables (except sugar beet); strawberry; cranberry; 
bushberry subgroup plus juneberry, lingonberry and salal; and oil seed 
crops.
    Syngenta has submitted complete residue data for the proposed 
tolerances on leafy vegetables, head and stem brassica vegetables, 
leafy brassica vegetables, grape commodities and the proposed increase 
in tolerance for the tuberous and corm vegetable subgroup.

B. Toxicological Profile

    1. Acute toxicity. The acute oral LD50 for thiamethoxam 
in the rat is 1,563 milligrams per kilogram of bodyweight(mg/kg bw). 
The acute dermal LD50 of thiamethoxam is >2,000 mg/kg bw. 
Thiamethoxam is non-toxic at atmospheric concentrations of 3.72 
milligrams per liter (mg/l). Thiamethoxam is minimally irritating to 
the eye, non-irritating to skin and is not a dermal sensitizer.
    In an acute neurotoxicity screening study in rats (OPPTS 870.6200), 
the no observed adverse effect level (NOAEL) was 100 milligrams per 
kilograms per day (mg/kg/day) with a NOAEL of 500 mg/kg/day based on 
drooped palpebral closure, decrease in rectal temperature and locomotor 
activity and increase in forelimb grip strength (males only). At higher 
dose levels, mortality, abnormal body tone, ptosis, impaired 
respiration, tremors, longer latency to first step in the open field, 
crouched over posture, gait impairment, hypo-arousal, decreased number 
of rears, uncoordinated landing during the righting reflex test, slight 
lacrimation (females only) and higher mean average input stimulus value 
in the auditory startle response test (males only).
    2. Genotoxicty. In gene mutation studies with S. typhimurium and E. 
coli (OPPTS 870.5100 and 870.5265, there was no evidence of gene 
mutation when tested up to 5,000 [mu]g/plate and there was no evidence 
of cytotoxicity.
    In a gene mutation study with chinese hamster V79 cells at HGPRT 
focus (OPPTS 870.5300) there was no evidence of gene mutation when 
tested up to the solubility limit.
    In a CHO cell cytogenetics study (OPPTS 870.5375) there was no 
evidence of chromosomal aberrations when tested up to cytotoxic or 
solubility limit concentrations.
    An in vivo mouse bone marrow micronucleus study (OPPTS 870.5395) 
was negative when tested up to levels of toxicity in whole animals; 
however, no evidence of target cell cytotoxicity. A UDS assay (OPPTS 
870.5550) was negative when tested up to precipitating concentrations.
    3.Reproductive and developmental toxicity. A prenatal developmental 
study in the rat (OPPTS 870.3700) resulted in Maternal and 
Developmental NOAELs of 30 mg/kg/day and 200 mg/

[[Page 31113]]

kg/day, respectively. The maternal lowest observed adverse effect level 
(LOAEL) is 200 mg/kg/day based on decreased body weight, body weight 
gain and food consumption. The developmental LOAEL was 750 mg/kg/day 
based on decreased fetal body weight and an increased incidence of 
skeletal anomalies.
    A prenatal developmental study in the rabbit (OPPTS 870.3700) 
resulted in maternal and developmental NOAELs of 50 mg/kg/day. The 
maternal and developmental LOAEL is 150 mg/kg/day. The maternal LOAEL 
is based on maternal deaths, hemorrhagic discharge, decreased body 
weight and food intake during the dosing period. The developmental 
LOAEL is based on decreased fetal body weights, increased incidence of 
post-implantation loss and a slight increase in the incidence of a few 
skeletal anomolies/variations.
    In a reproduction and fertility effects study in rats (OPPTS 
870.3800) the Parental/systemic NOAEL is 1.84 (males), 202.06 (females) 
mg/kg/day; the reproductive NOAEL is 0.61 (males) , 202.06 (females) 
mg/kg/day and the offspring NOAEL is 61.25 (males), 79.20 (females) mg/
kg/day. The parental/systemic LOAEL is 61.25 (males), not determined 
(females) mg/kg/day based on increased incidence of hyaline change in 
renal tubules in F0 and F1 males. The 
reproductive LOAEL is 1.84 (males), not determined (females ) mg/kg/day 
based on increased incidence and severity of tubular atrophy observed 
in testes of the F1 generation males. The offspring LOAEL is 
158.32 (males), 202.06 (females) mg/kg/day based on reduced body weight 
gain during the lactation period in all litters.
    4. Subchronic toxicity. A 90 day oral toxicity study in rats (OPPTS 
870.3100) resulted in a NOAEL of 1.74 (males, 92.5 (females) mg/kg/day. 
The LOAEL is 17.64 (male), 182.1 (female) mg/kg/day based on increased 
incidence of hyaline change of renal tubules epithelium (males), fatty 
change in adrenal gland of females, liver changes in females, all at 
the LOAEL.
    A 90 day oral toxicity study in mice (OPPTS 870.3100) resulted in a 
NOAEL of 1.41 (males), 19.2 (females) mg/kg/day. The LOAEL was 14.3 
(male), 231 (female) mg/kg/day based on increased incidence of 
hepatocellular hypertrophy. At higher dose levels: decrease in body 
weight and body weight gain, necrosis of individual hepatocytes, 
pigmentation of Kupffer cells, and lymphocytic infiltration of the 
liver in both sexes; slight hematologic effects and decreased absolute 
and relative kidney weights in males; and ovarian atrophy, decreased 
ovary and spleen weights and increased liver weights in females.
    In a 90 day oral toxicity study in dogs (OPPTS 870.3150), the NOAEL 
is 8.23 (males), 9.27 (females) mg/kg/day. The LOAEL is 32.0 (male), 
33.9 (female) mg/kg/day based on slightly prolonged prothrombin times 
and decreased plasma albumin and A/G ration (both sexes); decreased 
calcium levels and ovary weights and delayed maturation in the ovaries 
(female); decreased cholesterol and phospholipid levels, testis 
weights, spermatogenesis, and spermatic giant cells in testes (male).
    In a 28 day dermal study in rats (OPPTS 870.3200) the NOAEL was 250 
(male), 60 (female) mg/kg/day. The LOAEL was 1,000 (male), 250 (female) 
mg/kg/day based on increased plasma glucose, triglyceride levels, and 
alkaline phosphatase activity and inflammatory cell infiltration in the 
liver and necrosis if single hepatocytes in females and hyaline change 
in renal tubules and a very slight reduction in body weight in males. 
At higher dose levels in females, chronic tubular lesions in the 
kidneys and inflammatory cell infiltration in the adrenal cortex were 
observed.
    In a subchronic neurotoxicity screening study in rats (OPPTS 
870.6200) the NOAEL was 95.4 (male), 216.4 (female) mg/kg/day, both at 
highest dose tested. The LOAEL was not determined. No treatment related 
observations at any dose level. LOAEL was not achieved. May not have 
been tested at sufficiently high dose levels; however, a new study is 
not required because the weight of the evidence from other toxicity 
studies indicates no evidence of concern.
    5.Chronic toxicity. In a chronic toxicity study in dogs (OPPTS 
870.4100) the NOAEL was 4.05 (male), 4.49 (female) mg/kg/day. The LOAEL 
was 21.0 (male), 24.6 (female) mg/kg/day based on increase of 
creatinine in both sexes, transient decrease in food consumption in 
females, and occasional increase in urea levels, decrease in ALT, and 
atrophy of seminiferous tubules in males.
    In a mouse carcinogenicity study (OPPTS 870.4200) the NOAEL was 
2.63 (male), 3.68 (female) mg/kg/day. The LOAEL was 63.8 (male), 87.6 
(female) mg/kg/day based on hepatocyte hypertrophy, single cell 
necrosis, inflammatory cell infiltration, pigment deposition, foci of 
cellular alteration, hyperplasia of Kupffer cells and increased mitotic 
activity, also an increase in the incidence of hepatocellular adenoma 
(both sexes). At higher doses, there was an increase in the incidence 
of hepatocelluar adenocarcinoma (both sexes) and the number of animals 
with multiple tumors, evidence of carcinogenicity.
    In a combined chronic caricinogenicity study in rats (OPPTS 
870.4300) the NOAEL was 21.0 (male), 50.3 (female) mg/kg/day. The LOAEL 
was 63.0 (male), 255 (female) mg/kg/day based on increased incidence of 
lymphocytic infiltration of the renal pelvis and chronic nephropathy in 
males and decreased body weight gain, slight increase in the severity 
of hemosiderosis of the spleen, foci of cellular alteration in liver 
and chronic tubular lesions in kidney in females. No evidence of 
carcinogenicity.
    In a hepatic cell proliferation study in mice, the NOAEL was 16 
(male), 20 (female) mg/kg/day. The LOAEL was 72 (male), 87 (female) mg/
kg/day based on proliferative activity of hepatocytes. At higher dose 
levels, increases in absolute and relative liver weights, speckled 
liver, heptocellular glycogenesis/fatty change, heptocellular necrosis, 
apoptosis and pigmentation were observed.
    In a 28 day feeding study to assess replicative DNA synthesis in 
the male rat, the NOAEL was 711 mg/kg/day. The LOAEL was not 
established. Immunohistochemical staining of liver sections from 
control and high dose animals for proliferating cell nuclear antigen 
gave no indication for a treatment related increase in the fraction of 
DNA syntesizing hepatocytes in S-phase. CGA293343 did not stimulate 
hepatocyte cell proliferation in male rats.
    In a special study to assess liver biochemistry in the mouse, the 
NOAEL was 17 (male), 92 (female) mg/kg/day. The LOAEL was 74 (male), 92 
(female) mg/kg/day based on marginal to slight increases in absolute 
and relative liver weights, a slight increase in the microsomal protein 
content of the livers, moderate increases in the cytochrome P450 
content, slight to moderate increases in the activity of several 
microsomal enzymes, slight to moderate induction of cytosolic 
glutathionw S-transfersase activity. Treatment did not affect 
peroxisomal fatty acid B-oxidation.
    6. Animal metabolism. The metabolism of thiamethoxam in rats and 
livestock animals is adequately understood. The residues of concern 
have been determined to be parent thiamethoxam and its metabolite (N-
(2-chloro-thiazol-5-ylmethyl)-N'methyl- N''-nitro-guanidine.
    7. Metabolite toxicology. For most risk assessment purposes, 
residues of the metabolite corrected for molecular weight are 
considered to be toxicologically equivalent to parent

[[Page 31114]]

thiamethoxam. However, EPA has determined that the metabolite should 
not be included in cancer risk assessment.

C. Aggregate Exposure

    1. Dietary exposure. Permanent tolerances have been established (40 
CFR 180.565) for the combined residues of the insecticide thiamethoxam, 
3-[(2-chloro-5-thiazolyl)methyl]tetrahydro-5-methyl-N-nitro-4H-1,3,5-
oxadiazin-4-imine and it's metabolite (N-(2-chloro-thiazol-5-ylmethyl)-
N'-methyl-N''-nitro-guanidine), in or on a variety of RACs at levels 
ranging from 0.02 ppm to 1.5 ppm (including barley, canola, coffee 
(imported), corn, cotton, cucurbit vegetables, fruiting vegetables, 
pecans, pome fruits, sorghum, stone fruits, succulent beans, 
sunflowers, wheat, tuberous and corm vegetables and livestock 
commodities).
    Pending tolerances include: brassica (head and stem), brassica 
(leafy), bushberry subgroup (plus lingonberry, juneberry and salal), 
cranberry, grapes (fruit, raisins and juice), leafy vegetables, legume 
vegetable group, mint (peppermint and spearmint tops), oil seed crops 
(mustards, rapes, crambe, flax, safflower and borage), root vegetable 
(except sugar beets) subgroup and strawberry and a proposed tolerance 
increase for tuberous and corm vegetables.
    Tier I acute, tier II chronic and tier III cancer dietary exposure 
evaluations were made using the Dietary Exposure Evaluation Model 
(DEEM[reg]), version 7.76 from Exponent. All processing factors were 
taken from the EPA assessment of August 28, 2000 (DP Barcode D268606, 
PC Code 060109). Tolerance values have been established (40 CFR 
180.565(a)) for the combined residues of both thiamethoxam (CGA-293343) 
and its metabolite (CGA-322704) in or on a variety of raw agricultural 
commodities including meat, milk and eggs. These assessment results 
include all registered uses and proposed uses on mint, leafy 
vegetables, leafy Brassica vegetables, Brassica head and stem 
vegetables, grapes, cranberries, strawberries, oilseed crops, legume 
vegetables (crop subgroup 6), bushberries (crop subgroup 13B), root 
vegetables (except sugarbeets, crop subgroup 1B) and soybeans.
    For the tier I acute assessment, the proposed tolerance residues 
for these commodities (mint, 4.0 ppm; oilseed crops, 0.02 ppm; leafy 
vegetables, 2.0 ppm; leafy brassica vegetables, 2.0 ppm; brassica head 
and stem vegetables, 1.0 ppm; strawberries, 0.30 ppm; grapes, 0.15 ppm; 
grape juice, 0.20 ppm; grape raisins, 0.30 ppm; cranberries, 0.01 ppm; 
bushberries, 0.25 ppm; root vegetables subgroup 1A and 1B (except sugar 
beets), 0.10 ppm, root vegetables subgroup 1C, 0.25 ppm; legume 
vegetables, 0.02 ppm and soybeans, 0.02 ppm) were used along with the 
published tolerances for all other commodities. One-hundred percent of 
crop treated was assumed for all commodities in the acute assessment.
    In the tier II chronic assessment, the residue of concern was the 
sum of CGA-293343 and CGA-322704. Addition of the proposed crops 
mentioned above to the animal diets did not increase the previously 
calculated dietary burdens for any livestock commodities. Therefore, 
the residue values for secondary animal commodities were taken from the 
EPA assessment of August 28, 2000 which uses average field trial 
residue data with one-half limit of quantitation (LOQ) substitutions 
for all non-detectable residues. For the remaining registered and the 
proposed commodities listed above, the following residue data was used 
in the DEEM[reg]: cucurbit, leafy and Brassica vegetables and tomatoes 
- average field trial residues from soil-only (Platinum) application 
residue studies; stone fruits, mint, succulent beans, sunflower seed, 
and coffee - average field trial residue data with one-half LOQ 
substitutions for non-detectable residues; all other commodities - the 
proposed tolerances listed in the acute section above.
    For the cancer assessment, the residue values used for all animal 
commodities were the same as those used in the chronic assessment. For 
all of the remaining commodities, the residue of concern was only CGA-
293343 since CGA-322704 was found to be ``not carcinogenic to humans'' 
(EPA Memorandum, 12/24/03, DP Barcode 278328). Residue values were 
taken from field trial data where thiamethoxam was applied at the 
maximum labeled use rate and resulting crops were harvested at the 
minimum labeled PHI. For a number of crops, average residue values from 
field trials with soil-only (Platinum) applications of thiamethoxam 
were calculated to reflect currently proposed use directions. These 
crops included: leafy vegetables (crop group 4), Brassica vegetables 
(crop group 5), cucurbit vegetables (crop group 9) and fruiting 
vegetables (except peppers). Non-detectable residue values for these 
crops were substituted with a value of one-half LOQ. For the remaining 
crops, the average field trial residue values with one-half LOQ 
substitutions for non-detectable residues were used in the assessment 
if available and proposed tolerance residues were used if the field 
trial data was not available.
    All consumption data for these assessments was taken from the 
USDA's Continuing Survey of Food Intake by individuals (CSFII) with the 
1994-96 consumption database and the Supplemental CSFII children's 
survey (1998) consumption database. For the chronic and cancer 
assessments, the percent of crop treated values for all proposed crops 
were estimated by Syngenta Crop Protection according to current pest 
pressures and competitor's products. All other percent of crop treated 
values were estimated from the 2000-2003 Doane's Agricultural Marketing 
Service Database.
    i. Food. For the purposes of assessing the potential dietary 
exposure under the proposed tolerances, Syngenta Crop Protection has 
estimated aggregate exposure from all crops for which tolerances are 
established or proposed. The Tier I acute assessment utilized tolerance 
values and 100% of crop treated values. The Tier II chronic and Tier 
III cancer assessments utilized the residue and percent of crop treated 
values described above.
    a. Acute exposure. An acute reference dose of 0.10 mg/kg-bw/day for 
all population subgroups was based on a NOAEL of 100 mg/kg-bw/day from 
an acute neurotoxicity study in rats and an uncertainty factor of 100X 
(100X for combined interspecies and intraspecies variability). An 
additional FQPA safety factor of 10X was applied to all population 
subgroups due to the absence of a developmental neurotoxicity study. 
For the purpose of aggregate risk assessment, the exposure value was 
expressed in terms of margin of exposure (MOE). The MOE was calculated 
by dividing the NOAEL by the exposure for each population subgroup. In 
addition, exposure was expressed as a percent of the acute reference 
dose (%aRfD). Acute exposure to the most exposed sub-population 
(children 1 - 2 years old) resulted in a MOE of 6,873 (14.6 % of the 
acute RfD (aRfD) of 0.10 mg/kg-bw/day) at the 95th percentile of 
exposure. Since the benchmark MOE for this assessment was 1,000 and 
since EPA generally has no concern for exposures below 100% of the 
aRfD, Syngenta believes that there is a reasonable certainty that no 
harm will result from acute dietary (food) exposure to residues arising 
from the current and proposed uses for thiamethoxam.
    b. Chronic exposure. The chronic reference dose (RfD) for 
thiamethoxam is 0.0006 mg/kg-bw/day for all population subgroups and is 
based on a NOAEL of 0.6 mg/kg-bw/day from a two

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generation rat reproduction study. An uncertainty factor of 100X (for 
combined interspecies and intraspecies variability) and an additional 
FQPA safety factor of 10X was applied due to evidence of increased 
susceptibility to young rats following pre-/postnatal exposure. 
Exposure was expressed as MOE and percent of the reference dose (%RfD). 
Chronic exposure to the most exposed sub-population (children 1-2 years 
old) resulted in a MOE of 5,607 (17.8% of the chronic RfD of 0.0006 mg/
kg-bw/day). Since the benchmark MOE for this assessment was 1,000 and 
since EPA generally has no concern for exposures below 100% of the RfD, 
Syngenta believes that there is a reasonable certainty that no harm 
will result from chronic dietary (food) exposure to residues arising 
from the current and proposed uses for thiamethoxam.
    c. Lifetime exposure. The Q* value for thiamethoxam is 0.0377 (mg/
kg/day)-1 and is based on benign and malignant heptocellular 
tumors in mice in an 18-month carcinogenicity study. Lifetime exposure 
to the U.S. population of 0.000023 mg/kg-bw/day resulted in a Lifetime 
Risk of 8.63 x 10-7 which represents 86.3% of the EPA's 
Lifetime Risk limit of 1.0 x 10-6.
    ii. Drinking water. The EPA used the Pesticide Root Zone/Exposure 
Analysis Modeling System (PRZM/EXAMS) to estimate pesticide 
concentrations in surface water and SCI-GROW, which predicts pesticide 
concentrations in ground water. None of these models include 
consideration of the impact processing (mixing, dilution, or treatment) 
of raw water for distribution as drinking water would likely have on 
the removal of pesticides from the source water. The primary use of 
these models by the Agency at this stage is to provide a coarse screen 
for sorting out pesticides for which it is highly unlikely that 
drinking water concentrations would ever exceed human health levels of 
concern. Based on the SCI-GROW and PRZM/EXAMS models, the EPA 
calculated that estimated environmental concentrations of thiamethoxam 
at the highest use rate (0.125 lb active ingredients/Acre) are 1.9 
parts per billion (ppb) for acute and chronic exposure to ground water 
and 7.1 ppb and 0.43 ppb for acute and chronic exposure, respectively, 
to surface water. The EPA model-estimated estimated environenmental 
concentrations (EECs) are used below for comparison to Drinking Water 
Levels of Comparison (DWLOC) for hte acute, chronic and cancer 
assessments.
    a. Acute drinking water risk. Acute DWLOC were calculated based on 
an acute Populated Adjusted Dose (aPAD) of 0.1 mg/kg/day. For the acute 
assessment, the children (1-2 years old) subpopulation generated the 
lowest acute DWLOC of 854 ppb. The EPA has determined that the surface 
water acute EEC is 7.1 ppb and the ground water EEC is 1.9 ppb. Since 
the surface water value is greater than the ground water value, the 
surface water value will be used for comparison purposes and will 
protect for any concerns for ground water concentrations. Since the 
acute DWLOC of 854 ppb is considerably higher than the acute EEC of 7.1 
ppb, the EPA should not have a concern for acute risk to either surface 
or ground water.
    b. Chronic drinking water risk. Chronic DWLOC were calculated based 
on a chronic Populated Adjusted Dose (cPAD) of 0.0006 mg/kg/day. For 
the chronic assessment, the children (1-2 years old) subpopulation 
generated the lowest chronic DWLOC of approximately 4.9 ppb. The EPA 
has determined that the surface water chronic EEC is 0.43 ppb and the 
ground water EEC is 1.9 ppb. Since the ground water value is greater 
than the surface water value, the ground water value will be used for 
comparison purposes and will protect for any concerns for surface water 
concentrations. Since the chronic DWLOC of 4.9 ppb is higher than the 
chronic EEC of 1.9 ppb, the EPA should not have a concern for chronic 
risk to either surface or ground water.
    c. Lifetime cancer drinking water risk. Based on currently 
registered and proposed uses for thiamethoxam, Syngenta has determined 
a DWLOC for Lifetime Exposure of 2.0 ppb. At the currently registered 
maximum use rate of 0.125 lbs. active ingredient per acre per growing 
season, the EPA has used the SCI-GROW model to predict a ground water 
EEC of 1.9 ppb and used PRZM/EXAMS to predict a long-term average 
surface water EEC of 0.13 ppb. Since neither the ground water EEC nor 
the long-term average surface water EEC exceeds the cancer DWLOC for 
the general population, the cancer drinking water risk is below the 
EPA's level of concern.
    The EPA SCI-GROW model is a conservative screening level tool 
specifically designed to estimate pesticide concentrations in shallow 
ground water based on only three parameteres: use rate, laboratory 
determined aerobic soil degradation half life, and soil organic matter 
adsorption partition coefficient (Koc). The model is not 
able to separately predict acute and long-term average concentrations. 
A number of factors lead the EPA to believe that the actual lifetime 
exposure through drinking water will be less than the Lifetime DWLOC. 
These reasons are as follows:
    (a) Thiamethoxam is a systemic pesticide. The EPA's Tier I ground 
water model assumes that all of the product that is applied to the crop 
is available for runoff. Syngenta has submitted data to show that a 
percentage (15-25%) of the product is absorbed by the plant, resulting 
in that much less product available to leach into ground water. 
Although data submitted is on only two crops (beans and cucumbers), it 
is likely that the total amount of thiamethoxam available for ground 
water leaching is less than the amount the EPA uses as a model input.
    (b) Although the Agency model is based on aerobic soil half lives, 
the EPA's Lifetime Risk assessment is for lifetime exposure. Data 
indicate the anaerobic aquatic half-life for thiamethoxam is shorter 
than the aerobic soil half-life and longer than the aerobic aquatic 
half-life. Although the EPA is unable to predict, with a high degree of 
certainty, what happens to thiamethoxam in ground water over time, this 
does provide some support for the expectation that concentrations in 
ground water will decline between annual applications.
    (c) Shallow ground water modeling is not the perfect model for 
representing all drinking water from ground water sources. It is likely 
to be an overestimate of most drinking water concentrations, which tend 
to originate from deeper sources. The EPA's experience is that the 
model is reasonably accurate for shallow drinking water, but the Agency 
believes that it is less accurate for estimating concentrations in 
drinking water from deeper sources.
    (d) The Agency has established conditions of registration for the 
previous uses that include two prospective ground water studies and a 
retrospective monitoring study, so that the reasonable certainty of no 
harm finding will be sustained.
    (e) The dietary food risk is based on residue data derived from the 
average of field trials, which were performed at a higher application 
rate than what was accepted by the EPA. It is not unusual in the 
Agency's experience for field trial data to be an order of magnitude 
above actual monitoring. Since thiamethoxam has only recently been 
registered, actual monitoring data is not yet available. It is likely 
that the actual risk contribution from food will be much lower than 
current data indicate, which would result in a larger lifetime DWLOC. 
EPA should expect that this refined lifetime DWLOC would be larger than 
the EECs for the proposed uses.

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    Based on the previous points, the EPA should not expect that the 
general population would be exposed to levels exceeding the lifetime 
DWLOC
    2. Non-dietary exposure. Thiamethoxam is not currently registered 
for use on any sites that would result in residential exposure.

D. Cumulative Effects

    The potential for cumulative effects of thiamethoxam and other 
substances that have a common mechanism of toxicity has also been 
considered. Thiamethoxam belongs to a new pesticide chemical class 
known as the neonicotinoids. There is no reliable information to 
indicate that toxic effects produced by thiamethoxam would be 
cumulative with those of any other chemical including another 
pesticide. Therefore, Syngenta believes it is appropriate to consider 
only the potential risks of thiamethoxam in an aggregate risk 
assessment.

E. Safety Determination

    1. U.S. population. Syngenta concludes, as described above, that 
there is reasonable certainty that no harm to the U.S. population will 
result from aggregate acute or chronic dietary exposure to thiamethoxam 
residues including the proposed commodities.
    2. Infants and children. Syngenta concludes, as described above, 
that there is reasonable certainty that no harm to infants and children 
will result from aggregate acute or chronic dietary exposure to 
thiamethoxam residues including the proposed commodities.

F. International Tolerances

    There are no Codex MRLs established for residues of thiamethoxam.

[FR Doc. 04-12311 Filed 6-1-04; 8:45 a.m.]
BILLING CODE 6560-50-S