glufosinate-ammonium (Rely, Finale) Pesticide Petition Filing 7/02
ENVIRONMENTAL PROTECTION AGENCY
Notice of Filing a Pesticide Petition to Establish a Tolerance
for a Certain Pesticide Chemical in or on Food
AGENCY: Environmental Protection Agency (EPA).
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-2002-0123, must be
received on or before August 23, 2002.
ADDRESSES: Comments may be submitted by mail, electronically, or in
person. Please follow the detailed instructions for each method as
provided in Unit I.C. of the SUPPLEMENTARY INFORMATION. To ensure
proper receipt by EPA, it is imperative that you identify docket ID
number OPP-2002-0123 in the subject line on the first page of your
FOR FURTHER INFORMATION CONTACT: By mail: Joanne I. Miller,
Registration Support Branch, Registration Division (7505C), Office of
Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania
Ave., NW., Washington, DC 20460; telephone number: (703) 305-6224 e-
mail address: firstname.lastname@example.org.
I. General Information
A. Does this Action Apply to Me?
You may be affected by this action if you are an agricultural
producer, food manufacturer or pesticide manufacturer. Potentially
affected categories and entities may include, but are not limited to:
Categories NAICS codes potentially
Industry 111 Crop production
112 Animal production
311 Food manufacturing
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 the table could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether or not this action might apply to certain entities. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed under FOR FURTHER INFORMATION
B. How Can I Get Additional Information, Including Copies of this
Document and Other Related Documents?
1. Electronically. You may obtain electronic copies of this
document, and certain other related documents that might be available
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To access this document, on the Home Page select ``Laws and
Regulations'' and then look up the entry for this document under the
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2. In person. The Agency has established an official record for
this action under docket ID number OPP-2002-0123. The official record
consists of the documents specifically referenced in this action, any
public comments received during an applicable comment period, and other
information related to this action, including any information claimed
as confidential business information (CBI). This official record
includes the documents that are physically located in the docket, as
well as the documents that are referenced in those documents. The
public version of the official record does not include any information
claimed as CBI. The public version of the official record, which
includes printed, paper versions of any electronic comments submitted
during an applicable comment period, is available for inspection in the
Public Information and Records Integrity Branch (PIRIB), Rm. 119,
Crystal Mall 2, 1921 Jefferson Davis Highway, Arlington, VA,
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal
holidays. The PIRIB telephone number is (703) 305-5805.
C. How and to Whom Do I Submit Comments?
You may submit comments through the mail, in person, or
electronically. To ensure proper receipt by EPA, it is imperative that
you identify docket ID number OPP-2002-0123 in the subject line on the
first page of your response.
1. By mail. Submit your comments to: Public Information and Records
Integrity Branch (PIRIB), Information Resources and Services Division
(7502C), Office of Pesticide Programs (OPP), Environmental Protection
Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
2. In person or by courier. Deliver your comments to: Public
Information and Records Integrity Branch (PIRIB), Information Resources
and Services Division (7502C), Office of Pesticide Programs (OPP),
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921
Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
3. Electronically. You may submit your comments electronically by
e-mail to: email@example.com, or you can submit a computer disk as
described above. Do not submit any information electronically that you
consider to be CBI. Avoid the use of special characters and any form of
encryption. Electronic submissions will be accepted in Wordperfect 6.1/
8.0 or ASCII file format. All comments in electronic form must be
identified by docket control number OPP-2002-0123. Electronic comments
may also be filed online at many Federal Depository Libraries.
D. How Should I Handle CBI That I Want to Submit to the Agency?
Do not submit any information electronically that you consider to
be CBI. You may claim information that you submit to EPA in response to
this document as CBI by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
ith 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 version of the
official record. Information not marked confidential will be included
in the public version of the official record without prior notice. If
you have any questions about CBI or the procedures for claiming CBI,
please consult the person identified under FOR FURTHER INFORMATION
E. What Should I Consider as I Prepare My Comments for EPA?
You may find the following suggestions helpful for preparing your
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
7. To ensure proper receipt by EPA, be sure to identify the docket
control 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
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 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
Dated: July 11, 2002.
Director, Registration Division, Office of Pesticide Programs.
The petitioner summary of the pesticide petition is printed below
as required by section 408(d)(3) of the FFDCA. The summary of the
petition was prepared by the petitioner and represents the view of the
petitioner. EPA is publishing the petition summary verbatim without
editing it in any way. 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.
Summary of Petition
EPA has received a pesticide petition from Aventis CropScience USA,
P.O. Box 12014, 2 T.W. Alexander Drive, Research Triangle Park, NC
27709 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
180.473(c) by establishing a tolerance for residues of the herbicide
glufosinate-ammonium (butanoic acid, 2-amino-4-
(hydroxymethylphosphinyl-, monoammonium salt) and its metabolites, 3-
methylphosphinicopropionic acid, and 2-acetamido-4-methylphosphinico-
butanoic acid expressed as 2-amino-4-(hydroxymethylphosphinyl)butanoic
acid equivalents in or on the raw agricultural commodity (RAC) derived
from transgenic rice tolerant to glufosinate-ammonium: Grain at 1.0
parts per million (ppm), straw at 1.6 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. A metabolism study was conducted on transgenic
rice using 14C-glufosinate-ammonium. Two treatment regimes
were examined to simulate commercial application practices. The results
from both treatments were similar. The principal residue in the grain
at harvest was 3-methylphosphinicopropionic acid (Hoe 061517;
approximately 70% of the total radioactive residues (TRR). Other
relevant residues in the grain included N-acetyl-L-glufosinate (2-
acetamido-4-methylphosphinicobutanoic acid; Hoe 099730) at about 11% of
the TRR and parent at 5-6% of the TRR. In the straw, 3-
methylphosphinicopropionic acid was the predominate component
comprising approximately 60% of the TRR. Lesser amounts of the parent
(about 17% of the TRR) and N-acetylglufosinate (10-13% of TRR) were
found in the straw fraction. These results are consistent
with previous metabolism studies conducted using glufosinate-ammonium
on other transgenic crops. As a result of all the metabolism studies
conducted, the nature of residues found in transgenic plants as a
result of a treatment of glufosinate-ammonium is well understood.
2. Analytical method. The enforcement analytical method utilizes
gas chromatography for detecting and measuring levels of glufosinate-
ammonium and metabolites with a general limit of quantification of 0.05
ppm. This method allows detection of residues at or above the proposed
3. Magnitude of residues. Field residue trials were conducted
across the major regions of rice production in the U.S. The treatment
regime was selected to represent the use pattern that is the most
likely to result in the highest residues. Glufosinate-ammonium derived
residues did not exceed 0.74 ppm in rice grain, and 1.48 ppm in rice
straw when sampled at 70 days or more after the last treatment. No
concentration of the residues occurred when rice whole grain was
processed into polished grain and bran, whereas a concentration factor
of approximately 2.3 was found for rice hulls.
B. Toxicological Profile
1. Acute toxicity. Glufosinate-ammonium has been classified as
toxicity category III for acute oral, dermal, and inhalation toxicity;
and for eye irritation. Glufosinate-ammonium is not a dermal irritant
(toxicity category IV) nor is it a dermal sensitizer. The oral
LD50 is 2 g/kg in male rats, and 1.62 g/kg in female rats.
2. Genotoxicty. Based on results of a complete genotoxicity
database, there is no evidence of mutagenic activity in a battery of
studies, including: Salmonella spp., E. coli, in vitro mammalian cell
gene mutation assays, mammalian cell chromosome aberration assays, in
vivo mouse bone marrow micronucleus assays, and unscheduled DNA
3. Reproductive and developmental toxicity. In a developmental
toxicity study, groups of 20 pregnant female Wistar rats were
administered glufosinate-ammonium by gavage at doses of 0, 0.5, 2.24
10, 50 and 250 mg/kg/day from days 7 to 16 of pregnancy. The no
observed adversed effect level (NOAEL) for maternal toxicity is 10 mg/
kg/day; the lowest observed adverse effect level (LOAEL) is 50 mg/kg/
day based on vaginal bleeding and hyperactivity in dams. In the fetus,
the NOAEL is 50 milligrams/kilogram/day (mg/kg/day), based on dilated
renal pelvis observations at the LOAEL of 250 mg/kg/day. In a
developmental toxicity study, groups of 15 pregnant female Himalayan
rabbits were administered glufosinate-ammonium by gavage at doses of 0,
2.0, 6.3, or 20.0 mg/kg/day from days 7 to 19 of pregnancy. In maternal
animals, decreases in food consumption and body weight gain were
observed at the 20 mg/kg/day dose level. The NOAEL for maternal
toxicity was 6.3 mg/kg/day and that for developmental toxicity was 20
In a multi-generation reproduction study, glufosinate-ammonium was
administered to groups of 30 male and 30 female Wistar/Han rats in the
diet at concentrations of 0, 40, 120, or 360 ppm. The LOAEL for
systemic toxicity is 120 ppm based on increased kidney weights in both
sexes and generations. The systemic toxicity NOAEL is 40 ppm. The LOAEL
for reproductive/developmental toxicity is 360 ppm based on decreased
numbers of viable pups in all generations. The NOAEL is 120 ppm.
4. Subchronic toxicity. In a sub-chronic oral toxicity study,
glufosinate-ammonium was administered to 10 NMRI mice/sex/dose in the
diet at levels of 0, 80, 320 or 1,280 ppm equivalent to 0, 12, 48 or
192 mg/kg/day for 13 weeks. Significant (< 0.05) increases were
observed in serum aspartate aminotransferase and in alkaline
phosphatase in high-dose (192 mg/kg/day) males. Also observed were
increases in absolute and relative liver weights in mid-(48 mg/kg/day)
and high-dose males. The NOAEL is 12 mg/kg/day, the LOAEL is 48 mg/kg/
day based on the changes in clinical biochemistry and liver weights.
5. Chronic toxicity. In a combined chronic toxicity/oncogenicity
study, glufosinate-ammonium was administered to 50 Wistar rats/sex/dose
in the diet for 130 weeks at dose levels of 0, 40, 140, or 500 ppm
(mean compound intake in males was 0, 1.9, 6.8, and 24.4 mg/kg/day and
for females was 0, 2.4, 8.2 and 28.7 mg/kg/day, respectively). A dose-
related increase in mortality was noted in females at 140 and 500 ppm,
whereas in males increased absolute and relative kidney weights were
noted at 140 ppm, and 500 ppm. The NOAEL was considered to be 40 ppm.
No treatment-related oncogenic response was noted.
In an oncogenicity study, glufosinate-ammonium was administered to
50 NMRI mice/sex/dose in the diet at dose levels of 0, 80, 160 (males
only), or 320 (females only) ppm for 104 weeks. The NOAEL for systemic
toxicity is 80 ppm (10.82/16.19 mg/kg/day in males/females (M/F)), and
the LOAEL is 160/320 ppm (22.60/ 63.96 mg/kg/day in M/F), based on
increased mortality in males, increased glucose levels in M/F, and
changes in glutathione levels in males. No increase in tumor incidence
was found in any treatment group. In a chronic feeding study, technical
glufosinate-ammonium was fed to M/F beagle dogs for 12 months in the
diet at levels of 2.0, 5.0, or 8.5 mg/kg/day. The NOAEL is 5.0 mg/kg/
day based on clinical signs of toxicity, reduced weight gain and
mortality 8.5 mg/kg/day. In a rat oncogenicity study, glufosinate-
ammonium was administered to Wistar rats (60/sex/group) for up to 24
months at 0, 1,000, 5,000, or 10,000 ppm (equivalent to 0, 45.4, 228.9,
or 466.3 mg/kg/day in males, and 0, 57.1, 281.5, or 579.3 mg/kg/day in
females). The LOAEL for chronic toxicity is 5,000 ppm (equivalent to
228.9 mg/kg/day for male rats, and 281.5 mg/kg/day for females), based
on increased incidences of retinal atrophy. The chronic NOAEL is 1,000
ppm. Under the conditions of this study, there was no evidence of
arcinogenic potential. Dosing was considered adequate based on the
increased incidence of retinal atrophy.
6. Animal metabolism. Studies conducted in rats using
14C- glufosinate-ammonium have shown that th compound is
poorly absorbed (5-10%) after oral administration and is rapidly
eliminated primarily as the parent compound. The highest residue levels
were found in liver and kidney tissues.
The metabolic profile and the quantitative distribution of
metabolites were very similar in both goat and hen. The vast majority
of the dose was excreted, primarily as parent compound. The very
limited residues found in edible tissues, milk, and eggs were comprised
principally of glufosinate and 3-methylphosphinico-propionic acid (Hoe
061517), with lesser amounts of N-acetyl-L-glufosinate (Hoe 099730) and
2-methylohosphinico-acetic acid (Hoe 064619).
7. Metabolite toxicology. Additional testing has been conducted
with the major metabolites, 3-methylphosphinico-propionic acid, and N-
acetyl-L-glufosinate. Based on sub-chronic and developmental toxicity
study results, a profile of similar or less toxicity was observed for
the metabolites as compared to the parent compound, glufosinate-
8. Endocrine disruption. No special studies have been conducted to
investigate the potential of glufosinate-ammonium to induce estrogenic
or other endocrine effects. However, no evidence of estrogenic or other
endocrine effects have been noted in
any of the toxicology studies that have been conducted with this
product and there is no reason to suspect that any such effects would
C. Aggregate Exposure
1. Dietary exposure. Tolerances have been established (40 CFR
180.473) for the combined residues of glufosinate-ammonium and
metabolites in or on a variety of RACs. No appropriate toxicological
endpoint attributable to a single exposure was identified in the
available toxicity studies. EPA has, therefore, not established an
acute RfD for the general population including infants and children. An
acute RfD of 0.063 mg/kg/day was established, however, for the females
13+ subgroup. Therefore, an acute dietary analysis was conducted for
this sub-population; whereas, chronic dietary analysis was conducted
for the usual populations.
i. Food. An acute dietary analysis was conducted using the
DEEMTM software and the 1994-1996 CSFII consumption
database. The analysis assumed tolerance level residues for all
commodities and 100% of crop treated for all registered or pending
uses. This Tier One analysis resulted in an exposure of 0.007124 mg/kg
bw/day (95th percentile) for the female 13+ sub-population
(the only population of concern) representing 34% utilization of the
Chronic dietary analysis was conducted to estimate exposure to
potential glufosinate-ammonium residues in or on registered and
proposed commodities. The DEEMTM software and the 1994-1996
USDA food consumption data were used. Tolerance level residues were
assumed for all commodities. Percent crop treated values generated by
EPA/BEAD were incorporated as follows: Tree nuts, 1%; apples, 1%; field
corn, 2.6%; grapes, 1%;, and soybeans, 1%. Aventis CropScience
estimates that an upper bound value for cotton at market maturity is
20% and that for potatoes is 10%. All other crops are included at 100%
of crop treated. Chronic dietary exposure estimates from residues of
glufosinate-ammonium for the U.S. population represented approximately
25% of the chronic RfD; whereas that for children 1-6, the sub-
population with the highest exposure, represented approximately 61% of
the chronic RfD. The approach used is very conservative, yet still
indicates that dietary exposures for all segments of the population are
well within the chronic RfDs. This analysis was based on highly
conservative assumptions. The Agency has no concerns with RfD
utilization up to 100%.
ii. Drinking water. EPA's Standard Operating Procedure (SOP) for
Drinking Water Exposure and Risk Assessments was used to perform the
drinking water assessment. The models Screening concentrating in ground
water (SCI-GROW) and Pesticide Root Zone Model-Exposure Modeling System
(PRZM-EXAMS) were used to estimate the concentration of glufosinate-
ammonium that might occur in water. The acute drinking water level of
comparison (DWLOC) for females 13+ is 417 ppb. In comparison, the acute
drinking water estimated concentrations (DWEC) calculated by Generic
expected environmental concentration (GENEEC) is 127 ppb.
The chronic DWLOC calculated for adults is 185 ppb and that for
children/toddlers is 41 parts per billion (ppb). The chronic DWEC
calculated using a worst case scenario is 31 ppb (GENEEC). The drinking
water levels of comparison are based on highly conservative dietary
(food) exposures and are expected to be much higher in real world
situations reducing further the percent utilization of the DWLOC.
2. Non-dietary exposure. Glufosinate-ammonium is currently
registered for use on the following non-food sites: areas around
ornamentals, shade trees, Christmas trees, shrubs, walks, driveways,
flower beds, farmstead buildings, in shelter belts, and along fences.
It is also registered for use as a post-emergent herbicide on
farmsteads, areas associated with airports, commercial plants, storage
and lumber yards, highways, educational facilities, fence lines, ditch
banks, dry ditches, schools, parking lots, tank farms, pumping
stations, parks, utility rights-of -way, roadsides, railroads, and
other public areas and similar industrial and non-food crop areas. It
is also registered for lawn renovation uses.
The EPA has determined that there are no acute or chronic non-
dietary exposure scenarios. Further, the Agency has determined that it
is not appropriate to aggregate short-term and intermediate-term non-
dietary exposure with dietary exposures in risk assessments because the
end-points are different.
D. Cumulative Effects
Section 408(b)(2)(D)(v) requires that, when considering whether to
establish, modify, or revoke a tolerance, the Agency consider
``available information'' concerning the cumulative effects of a
particular pesticide's residues and ``other substances that have a
common mechanism of toxicity.'' EPA has indicated that, at this time,
the Agency does not have available data to determine whether
glufosinate-ammonium has a common mechanism of toxicity with other
substances or how to include this pesticide in a cumulative risk
assessment. Unlike other pesticides for which EPA has followed a
cumulative risk approach based on a common mechanism of toxicity,
glufosinate-ammonium does not appear to produce a toxic metabolite
produced by other substances. For the purposes of this tolerance
petition, therefore, it has not been assumed that glufosinate-ammonium
has a common mechanism of toxicity with other substances.
E. Safety Determination
1. U.S. population. Using the conservative assumptions described
above and based on the completeness and reliability of the toxicity
data, it is concluded that chronic dietary exposure to the registered
and proposed uses of glufosinate-ammonium will utilize at most 25% of
the chronic RfD for the U.S. population. The actual exposure is likely
to be significantly less than predicted by this analysis as data and
models that are more realistic are developed. Exposures below 100% of
the reference dose (RfD) are generally assumed to be of no concern
because the RfD represents the level at or below which daily aggregate
exposure over a lifetime will not pose appreciable risk to human
The acute population of concern, female 13+ utilizes 34% of the
acute RfD. This is a Tier One highly conservative assessment and actual
exposure is likely to be far less. Drinking water levels of comparison
based on dietary exposures are greater than highly conservative
estimated levels, and would be expected to be well below the 100% level
of the RfD, if they occur at all.
EPA has concluded that it is not appropriate to aggregate non-
dietary exposures with dietary exposures in a risk assessment because
the toxicity end-points are different.
Therefore, there is a reasonable certainty that no harm will occur
to the U.S. population from aggregate exposure (food, drinking water
and nonresidential) to residues of glufosinate-ammonium and
2. Infants and children. The toxicological database is sufficient
for evaluating prenatal and postnatal toxicity for glufosinate-
ammonium. There are no prenatal or postnatal susceptibility concerns
for infants and children, based on the results of the rat and rabbit
developmental toxicity studies and the 2-generation reproduction study.
Based on clinical signs of neurological toxicity in short
and intermediate dermal toxicity studies with rats, EPA has determined
that an added FQPA safety factor of 3x is appropriate of assessing the
risk of glufosinate-ammonium derived residues in crop commodities.
Using the conservative assumptions described in the exposure
section above, the percent of the chronic RfD that will be used for
exposure to residues of glufosinate-ammonium in food for children 1-6
(the most highly exposed sub-group) is 61%. Infants utilize 37% of the
chronic RfD. As in the adult situation, drinking water levels of
comparison are higher than the worst case DWECs and are expected to use
well below 100% of the RfD, if they occur at all.
Therefore, there is a reasonable certainty that no harm will occur
to infants and children from aggregate exposure to residues of
F. International Tolerances
Maximum residue limits (Codex MRLs) for glufosinate-ammonium and
metabolites in or on rice commodities have not been established by the
Codex Alimentarius Commission.
[FR Doc. 02-18586 Filed 7-23-02; 8:45 am]