[Federal Register Volume 68, Number 234 (Friday, December 5, 2003)]
[Notices]
[Pages 68044-68049]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-30164]


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ENVIRONMENTAL PROTECTION AGENCY

[OPP-2003-0276; FRL-7334-6]


Pyridalyl; 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-2003-0276, must 
be received on or before January 5, 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: Susan Stanton, Registration Division 
(7505C), Office of Pesticide Programs, Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 305-5218; 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:
    [sbull] Crop production (NAICS 111)
    [sbull] Animal production (NAICS 112)
    [sbull] Food manufacturing (NAICS 311)
    [sbull] Pesticide manufacturing (NAICS 32532)

[[Page 68045]]

    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 ID number OPP-2003-0276. 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.1. 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 submitted electronically or on 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-2003-0276. 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-2003-0276. 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

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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-2003-0276.
    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-2003-0276. 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 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 the elements 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: November 20, 2003.
Susan Lewis,
Acting Director, Registration Division, Office of Pesticide Programs.

Summary of Petition

    The petitioner's 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 Valent U.S.A. Corporation 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 chemical residues or an 
explanation of why no such method is needed.

Valent U.S.A. Corporation

PP 2F6459, and PP 2E6592

    EPA has received pesticide petitions (PP 2F6459, and PP 2E6592) 
from Valent U.S.A. Corporation, 1600 Riviera Ave., Suite 200, Walnut 
Creek, CA 94596-8025, and IR-4, 681 U.S. 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 the 
insecticide chemical pyridalyl, pyridine,2-[3-[2,6-dichloro-4-[(3,3-
dichloro-2-propenyl)oxy]phenoxy]propoxy]-5-(trifluoromethyl), in or on 
the raw agricultural commodities: Cottonseed at 0.4 parts per million 
(ppm); vegetable, fruiting, group 8, at 1.1 ppm; vegetable, leafy, 
except Brassica, group 4, at 20.0 ppm; Brassica, head and stem, 
subgroup 5A, at 5.0 ppm; Brassica, leafy greens, subgroup 5B, at 30.0 
ppm; turnip greens at 30 ppm; meat at 0.04 ppm; meat by-products at 
0.05 ppm; animal fat at 1.0 ppm; and whole milk at 0.1 ppm and to 
establish tolerances for residues of the insecticide chemical 
pyridalyl, pyridine,2-[3-[2,6-dichloro-4-[(3,3-dichloro-2-
propenyl)oxy]phenoxy]propoxy]-5-(trifluoromethyl) plus the metabolite 
S-1812-DP, 3,5-dichloro-4-[3-(5-trifluoromethyl-2-pyridyloxy)]propoxy 
phenol, in or on the raw agricultural commodity cotton gin by-products 
at 23.0 ppm. EPA has determined that the petitions contain 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 support granting of the 
petitions. Additional data may be needed before EPA rules on the 
petition.

A. Residue Chemistry

    1. Plant metabolism. The metabolism of pyridalyl in plants is well 
understood, having been investigated in cabbage, tomato, and cotton. 
The major residue in all crops is pyridalyl. A minor metabolic pathway 
in plants involves cleavage of the dichloropropenyl group to the 
phenol, S-1812-DP, which can be conjugated. Other minor metabolic 
pathways in cotton are oxidation of the dichloropropenyl group to the 
acid, S-1812-PhCH2COOH, and hydrolysis to give the pyridone, HTFP, 
which can be further hydroxylated to 3-hydroxy-5-
trifluoromethylpyridone (HPDO).
    2. Analytical method. Based on the metabolism of pyridalyl in plant 
and animals and the toxicology of the parent and metabolite, 
quantification of the parent pyridalyl and the metabolite S-1812-DP are 
sufficient to determine toxic residues. Practical analytical

[[Page 68047]]

methods for detecting and measuring levels of pyridalyl and its 
metabolite S-1812-DP have been developed and validated in all 
appropriate agricultural commodities and respective processing 
fractions. These analytical methods are suitable for monitoring of food 
with residues at the levels proposed for the tolerances. Methods have 
also, been developed and validated for determining pyridalyl and S-
1812-DP in animal matrices. The limit of quantitation (LOQ) of 
pyridalyl in the crop methods are 0.02 ppm in cottonseed, 0.1 ppm in 
cotton gin trash, and 0.02 ppm in vegetables. The LOQs of pyridalyl in 
the animal methods are 0.01 ppm in milk, 0.02 ppm in tissues, liver and 
kidney, and 0.10 ppm in fat.
    3. Magnitude of residues. Magnitude of residues were conducted in 
fruiting vegetables tomato and peppers (bell and non-bell), leafy 
vegetables (head and leaf lettuce, celery, and spinach), head and stem 
brassica vegetables (broccoli and cabbage), mustard greens, and cotton. 
Trials were conducted in all of the major use area for each of the 
crops as specified in the OPPTS Harmonized Guidelines OPPTS 860.1500 
with applications at the maximum use rate for each crop. As a result of 
the field trials, the following tolerances for the residues of 
pyridalyl are proposed for each of the crop groups, crops or matrices: 
Cottonseed at 0.4 ppm; turnip greens at 30 ppm; vegetables, leafy, 
except Brassica, group 4 at 20.0 ppm; brassica, head and stem, subgroup 
5A at 5.0 ppm; Brassica, leafy greens, subgroup 5B at 30 ppm; and 
vegetables, fruiting, group 8 at 1.1 ppm. Tolerances for the residues 
of pyridalyl plus the metabolite S-1812-DP are proposed for cotton gin 
by-products at 23.0 ppm. Processing studies were conducted with tomato 
and cottonseed. No tolerances are proposed for cottonseed and tomato 
processing commodities since no concentration factor was observed. 
Tolerances for residues of pyridalyl are also proposed for milk at 0.1 
ppm; meat at 0.04 ppm; animal fat at 1.0 ppm; and meat by-products at 
0.05 ppm.

B. Toxicological Profile

    A full battery of toxicology testing including studies of acute, 
subchronic, chronic, oncogenicity, developmental, reproductive and 
genotoxicity effects is available for pyridalyl. The acute toxicity of 
pyridalyl is low by all routes. Subchronic and chronic studies exhibit 
no observed adverse effect level (NOAEL) values from a low of 3.4 
milligrams/kilogram/day (mg/kg/day) (male rat combined toxicity/
oncogenicity study) to 1,000 mg/kg/day (28-day dermal toxicity study). 
Pyridalyl is not oncogenic and the weight-of-evidence indicates it is 
not genotoxic. There are no developmental concerns or reproductive 
effects.
    The lowest acute NOAEL of 50 mg/kg/day is derived from both the 
maternal and reproductive toxicity endpoint of the rabbit developmental 
toxicity study.
    The lowest chronic NOAEL of 40 ppm (2.8 mg/kg/day in males) is 
taken from the premating growth period in the 2-generation reproduction 
study.
    1. Acute toxicity. The acute toxicity of pyridalyl technical is low 
by all routes. Pyridalyl was not toxic when administered in limit tests 
orally, dermally and via inhalation to rats. It is not a skin irritant 
and is only a mild eye irritant. Pyridalyl was positive in skin 
sensitization tests. Pyridalyl and its formulated products will be 
placed into Toxicity Category III.
    2. Genotoxicty. The genotoxic potential of pyridalyl was studied in 
vitro in bacteria (ames test), in mammalian cells hypoxanthine-guanine 
phosphoribosyl transferase (HGPRT) and mouse lymphoma L5178Y TK+/-), in 
the chromosome aberration assay, and in vivo in the unscheduled DNA 
synthesis (UDS) test and the mouse micronucleus test. The test systems 
assayed did not show any evidence of pyridalyl genotoxicity except the 
in vitro mammalian cytogenetics (chromosome aberration) assay. The 
weight of the evidence indicates that pyridalyl does not raise 
significant genotoxicity concerns.
    3. Reproductive and developmental toxicity. Developmental effects 
of pyridalyl were studied in rats and rabbits and multigenerational 
effects on reproduction were studied in rats.
    i. Rat developmental. In a developmental toxicity study conducted 
with rats, the maternal NOAEL was 10 mg/kg/day based on the non-acute 
effects of reduced body weight gain and food consumption. There were no 
developmental effects, and the developmental NOAEL is 250 mg/kg/day, 
the highest dose tested (HDT).
    ii. Rabbit developmental. In a rabbit developmental toxicity study, 
the acute effects of maternal toxicity and decreased fetal weight was 
observed at 150 mg/kg/day. The maternal and developmental NOAEL is 50 
mg/kg/day.
    iii. Reproduction. In a rat reproduction study, there were no 
adverse effects of pyridalyl on reproductive parameters in the absence 
of parental toxicity. The reproductive, parental and offspring toxicity 
NOAEL is 40 ppm.
    4. Subchronic toxicity. Subchronic toxicity studies have been 
conducted with pyridalyl in the rat, mouse, and dog.
    i. Rats. Pyridalyl technical was tested in rats in a 3-month 
feeding study. Effects included decreased body weight gain, altered 
blood biochemistry, increased relative liver weight and 
histopathological changes in the liver, ovary, adrenal and lung. The 
NOAEL is 100 ppm (5.56 mg/kg/day in males and 6.45 mg/kg/day in 
females).
    ii. Mice. A 13-week feeding study in mice was conducted. Effects 
included decreased body weight gain, hematological and blood 
biochemical effects,increased liver weight, decreased kidney and ovary 
weights and histopathological changes in liver, kidney, ovary and 
adrenal. The NOAEL is 70 ppm in males (8.169 mg/kg/day) and 700 ppm in 
females (86.78 mg/kg/day).
    iii. Dogs. A 13-week oral (capsule) toxicity study was conducted in 
dogs. Effects included decreased body weight gain, clinical signs 
indicative of respiratory distress, hematological and blood 
biochemistry effects, increased liver, lung and kidney weights and 
histopathological alterations of the lung, kidney, adrenal and liver. 
The NOAEL was 10 mg/kg/day.
    iv. Dermal rat. A 28-day dermal toxicity study in rats with 
pyridalyl did not produce any signs of dermal or systemic toxicity at 
1,000 mg/kg/day, the highest dose tested (HDT).
    5. Chronic toxicity. Pyridalyl has been tested in chronic studies 
with dogs, rats and mice.
    i. Rats. In a 104-week combined chronic/oncogenicity study in rats, 
effects included decreased body weight gain, increased frequency of 
rearing (high dose females only), hematological alterations and 
histopathological alterations of the spleen. No oncogenicity was found. 
The NOAEL for this study is 100 ppm (3.4 mg/kg/day in males and 4.1 mg/
kg/day in females).
    ii. Mice. Pyridalyl was administered in the diet to mice for 78-
weeks. Effects included decreased body weight gain and food 
consumption/efficiency, and increased liver and kidney weights. The 
NOAEL of the study was 50 ppm (5.04 mg/kg/day in males and 4.78 mg/kg/
day in females)
    iii. Dogs. Pyridalyl was administered for 12-months by capsule to 
dogs. There were alterations in blood biochemistry (alkaline 
phosphatase and alanine aminotransaminase) and increased liver weights. 
The NOAEL of the study was 20 mg/kg/day.
    iv. Carcinogenicity. Pyridalyl did not produce carcinogenicity in 
chronic studies with rats or mice. Valent anticipates that the 
oncogenicity

[[Page 68048]]

classification of pyridalyl will be ``E'' (no evidence of 
carcinogenicity for humans).
    6. Animal metabolism. Rats metabolize and rapidly eliminate 
14C S-1812. Most of the administered dose was eliminated 
within 48 hours mainly in the feces. There were no apparent sex-related 
differences in either the rate of elimination of 14C S-1812 
or in the metabolite distribution. There was no apparent enzymatic 
induction as the metabolic pattern was unchanged by multiple (14-day) 
administrations of 14C S-1812 at 5 mg/kg/day.
    7. Metabolite toxicology. Two metabolites of pyridalyl, 2-hydroxy-
5-trifluoromethylpyridine (HTFP) and HPDO that occur in extremely low 
levels in plants and animals, were also tested for genetic toxicity. 
Each metabolite was tested in an in vitro bacterial (Ames test) and 
mammalian HGPRT assay mutagenesis assay as well as in an in vitro 
chromosome aberration test. Both metabolites were positive in the 
bacterial assay, but were negative in the mammalian mutagenesis assay. 
One metabolite, HPDO, was positive in the chromosome aberration test. 
The biological significance of this finding is uncertain given that 
only low levels of these compounds are detectible in plants or animals 
and that pyridalyl does not appear to be carcinogenic at high and 
chronic doses.
    8. Endocrine disruption. Data from the rat reproduction and 
subchronic studies indicated that pyridalyl may effect lipid metabolism 
and, consequently, hormone levels. These in vivo results suggested that 
S-1812 may have a modulating activity on steroid biosynthesis at doses 
generally exceeding MTD.
    To further understand these finding, two additional, non-guideline, 
mechanistic studies were conducted. A detailed analysis of the effect 
of S-1812 on serum steroid hormone levels was performed in rats exposed 
for 4 weeks to dose levels equivalent to those used in the rat 
reproduction study. And an in vitro study was conducted in rat primary 
Leydig cell and ovary cell cultures to investigate the effects of S-
1812 on the production of hormones and on the activity of enzymes that 
catalyze sex steroid hormone biosynthesis. These studies support the 
conclusion that S-1812 is not an endocrine disruptor in in vivo 
mammalian systems. Although, very weak inhibition of a single steroid 
biosynthesis pathway was observed in the in vitro study, effects 
possibly related to this conversion in mammalian systems were observed 
only at dose levels that greatly exceeded the maximum tolerated dose.

C. Aggregate Exposure

    1. Dietary exposure. Acute and chronic dietary analyses were 
conducted to estimate exposure to potential pyridalyl residues in or on 
the following crops and crop groups: Cottonseed, turnip greens, 
vegetables, leafy, except Brassica, group 4, Brassica, group 5 and 
vegetables, fruiting, group 8. using the Cumulative and Aggregate Risk 
Evaluation System (CARES) Version 1.3. Exposure estimates to water were 
made based upon modeling First Index Screening Tool Reservoir (FIRST 
model).
    i. Food--a. Acute. The acute dietary exposure estimate of pyridalyl 
residues in food at the 99.9th percentile was calculated to 
be 43% of the acute Reference Dose (aRfD) with a margin of exposure of 
235. The population subgroup with the highest exposure was non-nursing 
infants. The aRfD was defined as the NOAEL from a developmental 
toxicity study in rabbits and includes an uncertainty factor of 100 
(NOAEL = 50 mg/kg body weight (bwt)/day, aRfD = 0.5 mg/kg/day).
    b. Chronic. The chronic dietary exposure estimate of pyridalyl 
residues in food at the 100th percentile was calculated to 
be 1.4% of the chronic Reference Dose (cRfD) with a margin of exposure 
of 732. The population subgroup with the highest exposure was children 
1-2 years old. The cRfD was defined as the NOAEL from the 2-generation 
reproduction study in rats including an uncertainty factor of 100 
(NOAEL = 2.8 mg/kg bwt/day, cRfD = 0.028 mg/kg/day).
    These values are based on proposed tolerance level residues 
adjusted for percentages of the crop treated. No adjustments were made 
for common washing, cooking or preparation practices and as such are 
very conservative values.
    ii. Drinking water. Since pyridalyl is applied outdoors to growing 
agricultural crops, the potential exists for the parent or its 
metabolites to reach groundwater or surface water that may be used for 
drinking water. Screening Concentration in Groundwater (SCIGROW) 
simulation predicted zero S-1812 concentration in ground water 
indicating that S-1812 will not leach. This result is expected due the 
very high Koc value of pyridalyl. For the surface water FIRST (version 
1.0) simulation produced peak day concentration (acute) of 0.15 parts 
per billion (ppb). The peak FIRST concentration was used for both the 
acute and chronic exposure assessment. Based on these modeled drinking 
water concentrations, the worst-case acute/chronic dietary exposure 
from drinking water is estimated to be negligible (0.02% of the aRfD, 
and 0.003% of the cRfD for children).
    2. Non-dietary exposure. Pyridalyl is proposed only for 
agricultural uses and no homeowner or turf uses. Thus, no non-dietary 
risk assessment is necessary.

D. Cumulative Effects

    Section 408(b)(2)(D)(v) requires that the Agency must consider 
``available information'' concerning the cumulative effects of a 
particular pesticide's residues and ``other substances that have a 
common mechanism of toxicity.'' Available information in this context 
include not only toxicity, chemistry, and exposure data, but also 
scientific policies and methodologies for understanding common 
mechanism of toxicity and conducting cumulative risk assessments. For 
most pesticides, although, the Agency has some information in its files 
that may turn out to be helpful in eventually determining whether a 
pesticide shares a common mechanism of toxicity with any other 
substances, EPA does not at this time have methodologies to resolve the 
complex scientific issues concerning common mechanism of toxicity in a 
meaningful way for most registered pesticides.

E. Safety Determination

    1. U.S. population. Using the conservative assumption described 
above, based on the completeness and reliability of the toxicity data, 
it is concluded that aggregate exposure to the proposed uses of 
pyridalyl will utilize at most 43% of the acute RfD and 2% of the 
chronic RfD for the U.S. population and is likely to be much less, as 
more realistic data and models are developed. The Agency has no cause 
for concern if total acute residue contribution is less than 100% of 
the aRfD, because the RfD represents the level at or below which daily 
aggregate exposure over a lifetime will not pose appreciable risk to 
human health. Therefore, there is a reasonable certainty that no harm 
will occur to the U.S. population from aggregate exposure to residues 
of pyridalyl under the proposed use patterns.
    2. Infants and children. The toxicological data base for evaluating 
prenatal and postnatal toxicity for pyridalyl is complete with respect 
to current data requirements. There are no special prenatal and 
postnatal toxicity concerns for infants and children, based on the 
results of the rat and rabbit developmental toxicity studies or the 2-
generation reproductive toxicity study in rats. Using the conservative

[[Page 68049]]

assumption described above, based on the completeness and reliability 
of the toxicity data, it is concluded that, aggregate exposure to the 
proposed uses of pyridalyl will utilize at most 43% of the aRfD for 
non-nursing infants (the most highly exposed subgroup) and 2% of the 
cRfD for children 1-2 (the most highly exposed subgroup). The drinking 
water contribution to dietary exposure is insignificant. Therefore, 
there is a reasonable certainty that no harm will occur to infants and 
children from aggregate exposure to residues of pyridalyl.

F. International Tolerances

    There are currently no international tolerances for pyridalyl.
[FR Doc. 03-30164 Filed 12-4-03; 8:45 am]
BILLING CODE 6560-50-S