[Federal Register: January 29, 2003 (Volume 68, Number 19)]
[Notices]
[Page 4470-4475]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29ja03-62]
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ENVIRONMENTAL PROTECTION AGENCY
[OPP-2002-0318; FRL-7281-3]
S-metolachlor; 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-2002-0318, must be
received on or before February 28, 2003.
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: Joanne I. Miller, Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-
0001; telephone number: 703-305-6224; e-mail address:
miller.joanne@epa.gov.
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] (NAICS 111), e.g., Crop Production
[sbull] (NAICS 112), e.g., Animal Production
[sbull] (NAICS 311), e.g., Food Manufacturing
[sbull] (NAICS 32532), e.g., Pesticide Manufacturing
[sbull] (NAICS 32561),e.g., Antimicrobial Pesticide
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 NAICS codes have been provided to assist you and others
in determining whether this action might apply to certain entities. To
determine whether you or your business may be affected by this action,
you should carefully examine the applicability provisions in this
Notice of Filing a Pesticide Petition to Establish a Tolerance for a
Certain Pesticide Chemical in or on Food 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-2002-0138. 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.,
[[Page 4471]]
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 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-2002-0318. 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 opp-docket@epa.gov,
Attention: Docket ID Number OPP-2002-0318. 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-2002-0318.
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-2002-0318. 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
[[Page 4472]]
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: January 16, 2003.
Debra Edwards,
Acting Director, Registration Division, Office of Pesticide Programs.
Summaries of Petitions
The petitioner summaries of the pesticide petitions are printed
below as required by FFDCA section 408(d)(3). The summaries of the
petitions was prepared by the petitioners and represent the views of
the petitioners. 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.
6E4638, 8E5011, 6F6751, and 7F4897
EPA has received pesticide petitions (PP 6E4638, 8E5011, 6F6751,
and 7F4897) from the Interregional Research Project No. 4 (IR-4), and
Syngenta Crop Protection, New Jersey Agricultural Experiment Station,
P.O. Box 231, Rutgers University, New Brunswick, NJ 08903 and 410 Swing
Road, Greensboro, NC 27419, proposing pursuant to section 408(d) of the
FFDCA, 21 U.S.C. 346a(d), to amend 40 CFR part 180 to establish
tolerances for residues of S-metolachlor on grasses grown for seed
(6E4638), spinach (8E5011), sugar beets and sunflowers (7F4897), and
tomato (6F6751). Grasses grown for seed and tomato petitions have been
the subject of previous Federal Register notices on March 4, 1998, and
April 14, 1997, these petitions have been amended to request the
establishment of tolerances for S-metolachlor, by establishing a
tolerance for residues of S-metolachlor [acetamide, 2-chloro-N-(2-
ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)-, (S)] (CAS Number
873921-9) and its metabolites, determined as the derivatives, 2-[(2-
ethyl-6-methylphenyl)amino]-1-propanol and 4-(2-ethyl-6-methylphenyl)-
2-hydroxy-5-methyl-3-morpholinone, each expressed as the parent
compound in or on the raw agricultural commodity (RAC) grass forage,
grass hay, spinach, sugar beet, sugar beet dried pulp, sugar beet
molasses, sugar beet tops, sunflower, sunflower meal, and tomato at 12,
0.2, 0.5, 0.5, 1.0, 3.0, 15.0, 0.5, 1.0, and 0.1 (respectively) parts
per million (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 qualitative nature of S-metolachlor
residues in plants is adequately understood based upon available EPA
approved corn, potato, and soybean metabolism studies. The metabolism
of S-metolachlor involves conjugation with glutathione, breakage of
this bond to form the mercaptan, conjugation of the mercaptan with
glucuronic acid, hydrolysis of the methyl ether, and conjugation of the
resultant alcohol with a neutral sugar. EPA has determined that
residues of concern in plants include parent and metabolites,
determined as the derivatives CGA-37913 and CGA-49751.
2. Analytical method. The Pesticide Analytical Manual (PAM) Vol.
II, Pesticide Regulation (Sec. 180.368) lists a gas chromatography
nitrogen phosphorous detector (GC/NPD) method (Method 1) for
determining residues in or on plants and a gas chromatography mass
spectrometry detector (GC/MSD) method for determining residues in
livestock commodities. These methods determine residues of S-
metolachlor and its metabolites as either CGA-37913 or CGA-49751
following acid hydrolysis. The limit of quantitation (LOQ) for the
method is 0.03 ppm for CGA-37913 and 0.05 ppm for CGA-49751.
3. Magnitude of residues-Grasses grown for seed. This petition is
supported by six field residue tests conducted on grasses grown for
seed. Quantitative measurements of the metolachlor hydrolysates, CGA-
37913 and CGA-49751, were made for all samples and reported as parent
equivalents. In all residue tests, the active ingredient (a.i.) was
applied post-emergence at a maximum of 2.0 lbs. a.i./acre at the early
regrowth stage prior to weed emergence. The maximum residue in forage
was 27 ppm (60-day PHI). Residues in forage declined with increasing
PHI. Maximum residues in straw, screenings, and seed were 0.11 ppm,
0.04 ppm, and < 0.08 ppm, respectively.
i. Spinach. Magnitude of residue data on the spinach were collected
from 12 field trials. In 1994, four field trials were conducted to
collect magnitude of residue data in or on spinach. The treated plots
each received one post-seeding, pre-emergence, broadcast
[[Page 4473]]
application of a.i., targeting a rate of 1.0 lb a.i./acre. The spinach
was harvested 45 to 56 days after the application. No residues of CGA-
49751 were detected above the LOQ, 0.05 ppm, in spinach samples from
two of the three remaining sites. CGA-49751 was detected at 0.1 ppm in
one treated sample from Arkansas. Residues of CGA-37913 were detected
above the LOQ in samples from all three field sites. The CGA-37913
residues ranged from < 0.10 ppm to 0.33 ppm. The resulting maximum
total combined residues of CGA-49751 + CGA-37913 in samples treated at
the 1.0 lb a.i./acre rate is < 0.38 ppm.
In 1995, eight field trials were conducted in Maryland, Michigan,
New Jersey, Texas, and California. Each of the eight trials consisted
of at least an untreated control and one treated plot, where the
treated plot received one post-seeding, pre-emergence, broadcast
application of a.i., targeting a rate of 1.0 lb a.i./acre. The
California and Texas trials also included a second treated plot, which
received post-seeding, pre-emergence, broadcast application of a.i.,
targeting a rate of 2.0 lbs a.i./acre. The spinach was harvested 34 to
69 days after the application. The residues found in 1995 spinach
samples, treated targeting the 1.0 lb a.i./acre rate, ranged from less
than the LOQ, 0.05 ppm, to 0.85 ppm of CGA-49751, and ranged from less
than the LOQ, 0.03 ppm, to 0.107 ppm for CGA-37913 for a maximum
combined residue of 0.174 ppm. In the spinach samples treated targeting
the 2.0 lbs a.i./acre rate, CGA-49751 residues ranged from < 0.05 ppm
to 0.188 ppm and CGA-37913 residues ranged from 0.032 ppm to 0.075 ppm.
The maximum combined residues for a.i. at the 2.0 lbs a.i./acre
application rate is 0.263. The maximum residues found in or on spinach
treated with the proposed labeled rate of 1.0 lbs a.i./acre, was < 0.38
ppm for the combined residues of CGA-37913 and CGA-49741. Residues in
spinach treated at the 2.0 lbs a.i./acre application rate did not
exceed this combined residues, with a maximum combined residue of 0.263
ppm. IR-4 is conducting additional research to support the 2.0 lbs
a.i./acre application rate.
ii. Sugarbeets. Eleven sugar beet trials were conducted using six
different treatment scenarios. The maximum 1X use rate was 4.0 lbs.
a.i./acre applied preplant surface or preplant incorporated (1.33 lbs.
a.i./acre) plus a post foliar spray (2.66 lbs. a.i./acre). 3X and 5X
treatments were also conducted. Maximum residues at the 1X rate were 14
ppm in sugar beet tops and 0.32 ppm in sugar beet roots. In the
processing study, it was determined that tolerances would be required
in dried pulp and molasses, but not in refined sugar.
iii. Sunflower. A total of 15 residue trials were conducted in
major sunflower growing areas of the United States. Applications were
made at 1X and 2X the maximum labeled rate of 3.0 lbs. a.i./acre.
Processing was also conducted with seeds processed into meal, hulls,
crude oil, refined oil and soapstock. Based on these studies,
tolerances are proposed in sunflower seed at 0.5 ppm and in sunflower
meal at 1.0 ppm.
iv. Tomato. Thirteen field trials were conducted in major tomato
production areas across the United States. Both tomato and its
processed fractions were analyzed for residues of parent, measured as
CGA-37913 and CGA-49751. One application at 3.0 lbs. a.i./acre (1X) was
made post-foliar to tomato transplants. Exaggerated rate applications
(2X, 3X and 5X) were also made. Two of the 13 trials were used for
processing into tomato commodity products. No residues LOQ of 0.08 ppm)
were found at the 1X rate in the RAC tomatoes. In processed commodities
at the 1X rate of 3.0 lbs a.i./acre, residues of parent were found
below the method LOQ in tomato puree (0.4 ppm) and above the method LOQ
in dry pomace and tomato paste (0.16 and 0.13 ppm, respectively).
Because residues in tomato puree and paste (commodities listed in Table
1 of OPPTS 860.1000 as processed commodities of tomatoes) are less than
2X the LOQ of 0.08 ppm, tolerances are not required according to OPPTS
860.1520 (f)(3).
B. Toxicological Profile
1. Acute toxicity. The database for acute toxicity for S-
metolachlor is complete. S-metolachlor is moderately acutely toxic
(Toxicity Category III) by the oral and dermal route and relatively
non-toxic (Toxicity category IV) by the inhalation route. It causes
slight eye irritation (Toxicity Category III) and is non-irritating
dermally (Toxicity Category IV); the a.i. was found to be positive in a
dermal sensitization test but this effect is mitigated in end-use
product formulations.
2. Genotoxicty. The database for S-metolachlor has been deemed to
be adequate by EPA. Gene mutation studies (Guideline 870.5100),
micronucleus (Guideline 870.5395), and unscheduled DNA synthesis
(Guideline 870.5550) studies have recently been reviewed and approved
by EPA. There is no evidence of a mutagenic or cytogentic effect in
vivo or in vitro with S-metolachlor.
3. Reproductive and developmental toxicity. The database for
developmental and reproductive toxicity for S-metolachlor are
considered complete according to EPA reviews. The prenatal
developmental studies in the rat and rabbit with S-metolachlor revealed
no evidence of a qualitative or quantitative susceptibility in fetal
animals. No significant developmental toxicity was observed in most
studies even at the highest does tested (HDT). In a 2-generation
reproduction study, there was no evidence of parental or reproductive
toxicity at the HDT (80 millograms/kilogram/day (mg/kg/day)). The
results indicate that S-metolachlor is not embryotoxic or teratogenic
in either species at maternally toxic doses.
4. Subchronic toxicity. In a 90-day dietary study in rats with S-
metolachlor, no effects were observed in male or females at 208 and 236
mg/kg/day, respectively. In another 90-day dietary study in rats,
decreased body weight, reduced food consumption and food efficiency in
both sexes and increased kidney weight in males at 150 mg/kg/day; the
no observe adversed effect level (NOAEL) was 15 mg/kg/day. A 90-day dog
study with S-metolachlor in dogs has been accepted by EPA; no effects
were observed in males and females at 62 mg/kg/day and 74 mg/kg/day,
respectively, the HDT.
5. Chronic toxicity. The database that supports S-metolachlor is
considered adequate by EPA. A combined chronic toxicity/ carcinogenic
study in the rat satisfies the requirements for both the chronic
toxicity and carcinogenicity studies. No significant chronic toxicity
was found in either rats or dogs. In the rat, a decrease in body weight
was observed at the HDT. In the chronic dog study that supports S-
metolachlor, the only adverse effect was decreased body weight gain in
females at 33 mg/kg/day; the NOAEL was 10 mg/kg/day.
6. Animal metabolism. The database for S-metolachlor is considered
to be complete. In animals, S-metolachlor is extensively absorbed,
rapidly metabolized and almost totally eliminated in the excreta of
rats, goats, and poultry. Metabolism in animals proceeds through common
Phase 1 intermediates and glutathione conjugation.
7. Metabolite toxicology. The metabolism of S-metolachlor has been
well characterized in standard FIFRA metabolism studies. The
metabolites found are considered to be toxicologically similar to
parent. S-metolachlor does not readily undergo dealkylation to form an
aniline or quinone imine as has been reported for other members of the
chloroacetanilide class of chemicals. Therefore, as EPA has agreed, it
is not appropriate to include S-metolachlor with the group of
[[Page 4474]]
chloroacetanilides that readily undergo dealkylation, producing a
common toxic metabolite (quinone imine).
8. Endocrine disruption. S-Metolachlor does not belong to a class
of chemicals known or suspected of having adverse effects on the
endocrine system. There is no evidence that S-metolachlor has any
effect on endocrine function in developmental or reproduction studies.
Furthermore, histological investigation of endocrine organs in the
chronic dog, rat and mouse studies did not indicate that the endocrine
system is targeted by S-metolachlor, even at maximally tolerated doses
administered for a lifetime. There is no evidence that S-metolachlor
bioaccumulates in the environment.
C. Aggregate Exposure
1. Dietary exposure. A Tier III/IV chronic dietary exposure
analysis was conducted on S-metolachlor using field trial and market
basket (MB) residues. Field trial residues were adjusted for PCT
whereas MB residues were not, since this information is inherent in the
data. The PCT was assumed to be 100% for all commodities for which no
PCT information was available. The chronic assessment was conducted for
S-metolachlor using the Dietary Exposure Evaluation Model
(DEEMTM), version 7.76) by exponent and food consumption
information from Department of Agriculture (USDA's) 1994-96 Continuing
Survey of Food Intake by Individuals (CSFII) and the Supplemental CSFII
children's survey (1998). For this chronic assessment, the field trial
values were averaged and entered into the DEEMTM software.
Syngenta Market Basket Survey (SMBS) S-metolachlor data were
available for the following commodities: Milk, potatoes, and tomatoes.
The SMBS was conducted from September 1999 through September 2000.
Following the Agency tier ranking system, these chronic dietary
assessments are considered as Tier III (utilizing field trial data) and
Tier IV (utilizing SMBS and PDP data) assessments.
The chronic reference dose (RfD) for S-metolachlor is 0.10 mg/kg
body weight/day and is based on a 1-year dog study with a NOAEL of 9.7
mg/kg body weight/day and a safety factor of 100X. No additional FQPA
safety factor is required, nor was applied in this assessment. S-
metolachlor is not considered acutely toxic and therefore, acute
dietary exposure was not determined. For the purpose of aggregate
assessment, the exposure values were expressed in terms of margin of
exposure (MOE) which was calculated by dividing the NOAEL by the
exposure for each population subgroup. The benchmark MOE for this
assessment is 100.
i. Food. The risk from chronic dietary exposure to S-metolachlor is
considered to be very low. Based on worst-case assumptions, the chronic
exposure assessment did not result in any MOE less than 55,428 for even
the most impacted population subgroup (children 1-6 years). Syngenta
believes that the MOE for chronic exposure would be well above 100 for
any population group. A MOE of 100 or more is considered satisfactory.
The percent of the chronic RfD ranged from 0.05% for seniors to 0.2%
for children 1-6 and Non-nursing infants, theoretically the most
exposure population subgroups.
ii. Drinking water. Other potential sources of exposure of the
general population to residues of S-metolachlor are residues in
drinking water and exposure from non-occupational sources. The
degradation of S-metolachlor is microbially mediated with an aerobic
soil metabolism primary half-life of less than 30 days and subsequently
soil binding predominates. S-metolachlor Koc's vary from 110-369. S-
metolachlor is stable to hydrolysis and while aqueous and soil
photolysis occur, they are not expected to be prominent pathways in the
environment.
The predominant crop for S-metolachlor is corn and accordingly an
Index Reservoir PRZM/EXAMS was run using EPA's standard corn scenario.
The model simulated two applications to the same plot: Pre-emergence
(2.67 kg a.i./hectare (ha) post-emergence (1.50 kg a.i./ha). The mean
annual average EEC was 11.77 part per billion (ppb). It should be noted
that extensive monitoring data suggests that this estimated
environmental concentration (EEC) is a conservative estimate. For the
vast majority of locations sampled, the peak measured concentration
does not approach 12 ppb, and the annual average would be expected to
be much lower.
The Chronic drinking water levels of concern (DWLOC) was calculated
based on a chronic reference dose (cRfD) of 0.097 mg/kg/day. Non-
nursing infants are the most sensitive subpopulation and their DWLOC is
estimated to be 544 ppb which corresponds to a %cRfD value of 2.2% with
an MOE value of 4,621. Thus, the DWLOC is considerably higher than the
EEC of 11.77 ppb and the MOE is well above the benchmark value of 100.
2. Non-dietary exposure. S-metolachlor is labeled for use on warm-
season turf and landscape ornamentals. Although it is primarily used on
sod farms and commercial landscape ornamentals, it can be used by
licensed pest control operators or lawn care operators on residential
turf. Since S-metolachlor can only be applied to warm-season turf
varieties (bermudagrass, Zoysiagrass, St. Augustinegrass, and
Centipedegrass), its use on turf is limited to the southern states.
Non-dietary residential exposure may occur to homeowners or
children as a result of exposure during re-entry activities. Using
surrogate dislodgeable foliar residue data, and conservative standard
EPA exposure scenarios, exposure through the dermal route was
calculated. Based on the use pattern, which restricts to number of
application to one per year, only short-term risks need to be
considered. The relevant toxicological endpoint for short-term dermal
risks is the NOAEL of 100 mg/kg/day from a 21-day dermal toxicity study
in rabbits. No acute oral hazard has been identified following an acute
exposure to S-metolachlor and, therefore, no nondietary assessment is
needed.
The short-term dermal post-application risks for adults and
children are acceptable, ranging from 520 to 870. These risk estimates
exceed the EPA's level of concern for S-metolachlor (all MOEs are
greater than 100).
3. Aggregate exposure (drinking water and dietary exposure). Using
the total MOE equation for the determination of aggregate chronic
exposure (food and drinking water only) resulted in an aggregate
MOET of 4,630 for the most sensitive subpopulation, non-
nursing infants. For this particular subpopulation, there are no non-
dietary exposure contributions to the MOET aggregate value.
D. Cumulative Effects
EPA has examined the common mechanism potential for S-metolachlor
and has concluded that S-metolachlor should not be included with some
pesticides that comprise the class of chloroacetanilides included in a
``Common Mechanism Group''. Therefore, a cumulative assessment is not
necessary for S-metolachlor.
E. Safety Determination
1. U.S. population. Based on the aggregate assessment described
above and the completeness and reliability of the toxicity data, it is
concluded that aggregate exposure to S-metolachlor (including the
proposed uses) in food will utilize less than 0.1% of the cRfD for the
U.S. population. EPA generally has no concern for exposures below
[[Page 4475]]
100% of the RfD because the RfD represents the level at or below which
daily aggregate dietary exposure over a lifetime will not pose
appreciable risks to human health. Despite the potential for exposure
to S-metolachlor in drinking water and from non-dietary, non-
occupational exposures, the assessment presented above demonstrates
that the high levels of safety exist for current and proposed uses of
S-metolachlor; it is not expected that aggregate exposure from all
sources will exceed 100% of the RfD. Therefore, one can conclude there
is a reasonable certainty that no harm will result from aggregate
exposure to S-metolachlor.
2. Infants and children. FFDCA section 408 provides that EPA may
apply an additional safety factor for infants and children in the case
of threshold effects to account for prenatal and postnatal toxicity and
the completeness of the database. Based on the current toxicological
data requirements, the database relative to prenatal and postnatal
effects for children is complete. A full consideration of the available
reproductive toxicity data supporting S-metolachlor demonstrates no
increased sensitivity to infants and children. Therefore, it is
concluded that an additional uncertainty factor is not warranted to
protect the health of infants and children and that the cRfD at 0.1 mg/
kg/day is appropriate for assessing aggregate risk to infants and
children from use of S-metolachlor.
Based on the aggregate assessment described above, the percent of
the cRfD that will be utilized by aggregate exposure to residues of S-
metolachlor is less than 0.2% for non-nursing infants and children 1 to
6 years old, and 0.1% for children 7 to 12 years old. EPA generally has
no concern for exposures below 100% of the RfD because the RfD
represents the level at or below which daily aggregate dietary exposure
over a lifetime will not pose appreciable risks to human health.
Despite the potential for exposure to S-metolachlor in drinking water
and from non-dietary, non-occuptional exposure, the assessment
described above demonstrates that it is not expected that aggregate
exposure from all sources provides for a large margin of safety and
will exceed 100% of the RfD. Therefore, based on the completeness and
reliability of the toxicity data and the exposure assessment, it is
concluded there is a reasonable certainty that no harm will result to
infants and children from aggregate exposure to S-metolachlor residues.
F. International Tolerances
There are no Codex Alimentarius Commission maximum residue levels
(MRL's) established for residues of S-metolachlor in or on raw
agricultural commodities.
[FR Doc. 03-2019 Filed 1-28-03; 8:45 am]
BILLING CODE 6560-50-S