triasulfuron (Amber) Pesticide Petition Filing 5/98
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ENVIRONMENTAL PROTECTION AGENCY
Monsanto Company; Pesticide Tolerance Petitions Filing
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 the docket control number PF-806, must
be received on or before June 29, 1998.
ADDRESSES: By mail submit written comments to: Information and Records
Integrity Branch, Public Information and Services Divison (7502C),
Office of Pesticides Programs, Environmental Protection Agency, 401 M
St., SW., Washington, DC 20460. In person bring comments to: Rm. 119,
CM #2, 1921 Jefferson Davis Highway, Arlington, VA.
Comments and data may also be submitted electronically by following
the instructions under ``SUPPLEMENTARY INFORMATION.'' No confidential
business information should be submitted through e-mail.
Information submitted as a comment concerning this document may be
claimed confidential by marking any part or all of that information as
``Confidential Business Information'' (CBI). CBI should not be
submitted through e-mail. Information marked as CBI will not be
disclosed except in accordance with procedures set forth in 40 CFR part
2. A copy of the comment that does not contain CBI must be submitted
for inclusion in the public record. Information not marked confidential
may be disclosed publicly by EPA without prior notice. All written
comments will be available for public inspection in Rm. 1132 at the
address given above, from 8:30 a.m. to 4 p.m., Monday through Friday,
excluding legal holidays.
FOR FURTHER INFORMATION CONTACT: James A. Tompkins, Registration
Support Branch, Registration Division (7505C), Office of Pesticide
Programs, Environmental Protection Agency, 401 M St., SW, Washington,
DC 20460. Office location, telephone number, and e-mail address: Rm.
239, Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA
22202, (703) 305-5697; e-mail: email@example.com.
SUPPLEMENTARY INFORMATION: EPA has received a pesticide petition as
follows proposing the establishment and/or amendment of regulations for
residues of certain pesticide chemical in or on various food
commodities under section 408 of the Federal Food, Drug, and Comestic
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 supports
granting of the petition. Additional data may be needed before EPA
rules on the petition.
The official record for this notice of filing, as well as the
public version, has been established for this notice of filing under
docket control number [PF-806] (including comments and data submitted
electronically as described below). A public version of this record,
including printed, paper versions of electronic comments, which does
not include any information claimed as CBI, is available for inspection
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal
holidays. The official record is located at the address in
``ADDRESSES'' at the beginning of this document.
Electronic comments can be sent directly to EPA at:
Electronic comments must be submitted as an ASCII file avoiding the
use of special characters and any form of encryption. Comment and data
will also be accepted on disks in Wordperfect 5.1 file format or ASCII
file format. All comments and data in electronic form must be
identified by the docket number (insert docket number) and appropriate
petition number. Electronic comments on this proposed rule may be filed
online at many Federal Depository Libraries.
List of Subjects
Environmental protection, Agricultural commodities, Food additives,
Feed additives, Pesticides and pests, Reporting and recordkeeping
Dated: May 14, 1998.
Director, Registration Division, Office of Pesticide Programs.
Summaries of Petitions
Petitioner summaries of the pesticide petitions are printed below
as required by section 408(d)(3) of the FFDCA. The summaries of the
petitions were prepared by the petitioners and represent the views of
the petitioners. EPA is publishing the petition summaries verbatim
without editing them 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.
2. Norvartis Crop Protection Inc.
EPA has received a pesticide petition (PP 3F4225) from Norvartis
Crop Protection INC., P.O. Box 18300, Greensboro, NC 27419, proposing
pursuant to section 408(d) of the Federal Food, Drug and Cosmetic Act,
21 U.S.C. 346a(d), to amend 40 CFR part 180 extending time limited
tolerances for residues of Triasulfuron in or on the raw agricultural
commodity grass, forage at 7.0 ppm, grass, hay at 2.0 ppm and kidney of
cattle, goats, hogs, horses, and sheep at 0.5 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 nature of the residue in plants is
understood. The metabolism of triasulfuron in wheat proceeds by
hydroxylation of the phenyl ring and hydrolytic cleavage of the urea
bridge. The residue of regulatory concern is parent triasulfuron.
Because the metabolism work in wheat can be translated to grasses,
parent compound is the residue of regulatory concern for grasses.
2. Analytical method. Triasulfuron in grass was analyzed by
Analytical Method AG-500B which the validated tolerance enforcement
method. According to Method AG-500B, triasulfuron is extracted with a
mixture of methanol and phosphoric acid. The extract is diluted with
water. Triasulfuron residues are partitioned into dichloromethane and
cleaned up on a BondElut CN solid phase extraction column. Residues are
determined by column-switching HPLC utilizing a Lichrosorb CN column
followed by a Zorbax ODS column, with UV detection at 232 nm.
3. Magnitude of residues. A total of 16 field trials have been
conducted in 16 States. Seven sites tested bromegrass or fescue, 5 used
bluegrass, and 4 used bermudagrass. A total of 69.6% of U.S.
pastureland was represented by these trials. Two post broadcast spray
applications were made 60-days apart at a rate of 12 grams active
ingredient/A/application. Time-limited tolerances were previously
established at 7 ppm in grass, forage and 2 ppm in grass, hay pending
the submission of additional residue trials. These additional field
trials which are included in the numbers above did not show residues
exceeding the current tolerances in either grass, forage (0-day PHI) or
grass, hay (30-days PHI). The feeding of either substrate to beef or
dairy cattle will not result in existing tolerances in animal
commodities being exceeded.
B. Toxicological Profile
1. Acute toxicity. Triasulfuron has a low order of acute toxicity.
The rat oral LD<INF>50</INF> is > 5,000 milligrams/kilogram (mg/kg),
the acute rabbit dermal LD<INF>50</INF> is > 2,000 mg/kg and the rat
inhalation LC<INF>50</INF> is > 5.2 mg/L. Triasulfuron is slightly
irritating to the eye but not irritating to skin. It is not a skin
sensitizer in guinea pigs. The commercial formulation of triasulfuron
(75WP) has a similar acute toxicity profile. Both the technical
material and the 75WP formulation require a Category III CAUTION Signal
Word on the label.
2. Genotoxicty. Assays for genotoxicity were comprised of tests
evaluating the potential of triasulfuron to induce point mutations
(Salmonella typhimurium, Saccharomyces cerevisiae and mouse lymphoma
L5178Y/TK/+/- cells), chromosome aberrations (micronucleus test in
Chinese hamsters) and the ability to induce either unscheduled DNA
synthesis in rat hepatocytes and human fibroblasts. The results
indicate that triasulfuron is not mutagenic or clastogenic and does not
induce unscheduled DNA synthesis.
3. Reproductive and developmental toxicity. The developmental and
teratogenic potential of triasulfuron was investigated in rats and
rabbits. The results indicate that triasulfuron was maternally toxic in
the rat at doses of > 300 mg/kg/day. Developmental toxicity in the form
of delayed skeletal maturation was observed only at the highest dose
tested (HDT) of 900 mg/kg/day. The corresponding maternal and
developmental NOELs were established at doses of 100 and 300 mg/kg/day,
respectively in the rat. In the rabbit, maternal toxicity was observed
at the HDT of 240 mg/kg/day; no evidence of developmental toxicity was
present at 240 mg/kg/day. The maternal developmental NOELs were 120 and
240 mg/kg/day, respectively. No evidence of teratogenicity was observed
at the HDT in either the rat or rabbit.
There was no effect of triasulfuron on reproductive performance in a 2
generation rat reproduction study conducted at doses of 1, 50 and 250
mg/kg/day. Maternal and fetal toxicity as indicated by decreased body
weight gain was noted at the HDT of 250 mg/kg/day. The maternal and
developmental NOEL was 50 mg/kg/day.
4. Subchronic toxicity. The subchronic toxicity of triasulfuron was
evaluated in the rat and dog at high doses. Triasulfuron was poorly
tolerated in the rat at doses of > 516 mg/kg/day as indicated by
increased mortality, decreased body weight gain and kidney damage due
to the presence of triasulfuron-containing calculi present in the
urogenital tract. The NOEL in the rat was 10 mg/kg/day. Triasulfuron
was not well tolerated by the dog at doses of 10,000 ppm (250 mg/kg/
day) as indicated by body weight reduction, anemia, and effects on the
spleen, liver and kidney. The NOEL was 1,000 ppm (33 mg/kg/day).
5. Chronic toxicity. The chronic toxicity of triasulfuron was
investigated in long term studies in the rat, mouse and dog. Target
organs included the liver, kidney and blood. NOELs were established at
dose levels of 32.1, 1.2, and 129 mg/kg/day, respectively. The mouse is
the most sensitive species with a NOEL = 1.2 mg/kg/day. The
carcinogenicity studies on triasulfuron showed no evidence of an
oncogenic response in either mouse or rat. The chemical is classified
in category E.
6. Animal metabolism. The metabolism of triasulfuron has been well
characterized in standard FIFRA rat, goat and poultry metabolism
studies. Parent triasulfuron accounts for the majority of the excreted
dose in these species. Cleavage of the sulfonylurea bridge occurs at a
low rate but it is more prevalent in goats and hens than in rats.
Hydroxylation of the phenyl ring, which constitutes the major metabolic
pathway elucidated in wheat, also was found in the rat. None of the
metabolites identified in these studies are considered to be
toxicologically different than parent.
7. Metabolite toxicology. The metabolism of triasulfuron has been
well characterized in rat, goat and poultry metabolism studies. None of
the metabolites identified in these studies are considered to be
toxicologically different than parent.
8. Endocrine disruption. Triasulfuron does not belong to a class of
chemicals known or suspected of having adverse effects on the endocrine
system. There was no effect of triasulfuron on reproductive performance
in a 2-generation rat reproduction study conducted at doses of 1, 50
and 250 mg/kg/day. Although residues of triasulfuron have been found in
raw agricultural commodities, there is no evidence that triasulfuron
bioaccumulates in the environment.
C. Aggregate Exposure
1. Food. Novartis has estimated the aggregate exposure to
triasulfuron based on the established and time-limited tolerances for
triasulfuron (40 CFR 180.459). The theoretical maximum residue
contribution to diet is obtained by multiplying the tolerance level
residue for all these raw agricultural commodities by the consumption
data which estimates the amount of these products consumed by various
population subgroups. Because some of these raw agricultural
commodities (e.g. wheat and barley forage and fodder, grass forage and
hay) are fed to animals, the transfer of residues to animal commodities
has been calculated based on a conservatively constructed cattle diet.
In addition, Novartis has conservatively assumed that 100% of the raw
agricultural commodities contain residues of triasulfuron at tolerance
2. Drinking water. Another potential source of exposure of the
general population to residues of pesticides are residues in drinking
water. The potential for triasulfuron to enter surface or groundwater
sources of drinking water is limited because of the low use rate. The
Maximum Contaminant Level Guideline (MCLG) calculated for triasulfuron
according to EPA's procedures is 84 ppb, a value that is substantially
greater than levels that are likely to be found in the environment
under proposed conditions of use.
3. Non-dietary exposure. Novartis has evaluated the estimated non-
occupational exposure to triasulfuron and concludes that the potential
for non-occupational exposure to the general population is unlikely
since triasulfuron is not planned to be used in or around the home,
including home lawns.
D. Cumulative Effects
Novartis also has considered the potential for cumulative effects
of triasulfuron and other chemicals belonging to this class that may
have a common mechanism of toxicity. Novartis concluded that
consideration of a common mechanism of toxicity is not appropriate at
this time since there is no data to establish whether a common
E. Safety Determination
1. U.S. population. Using the conservative exposure assumptions
described above, based on the completeness and reliability of the
toxicity data, Novartis has concluded that aggregate exposure to
triasulfuron will utilize a maximum of 4.63% of the RfD for the U.S.
population based on chronic toxicity endpoints. 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. Therefore,
Novartis concludes that there is a reasonable certainty that no harm
will result from aggregate exposure to triasulfuron or residues of
triasulfuron that may appear in raw agricultural commodities.
2. Infants and children. In assessing the potential for additional
sensitivity of infants and children to residues of triasulfuron,
Novartis has considered data from developmental toxicity studies in the
rat and rabbit and a 2-generation reproduction study in the rat on
triasulfuron. The developmental toxicity studies are designed to
evaluate adverse effects on the developing organism resulting from
chemical exposure during prenatal development to one or both parents.
Reproduction studies provide information relating to effects from
exposure to a chemical on the reproductive capability of mating animals
and data on systemic toxicity.
Developmental toxicity in the form of delayed skeletal maturation
was observed in the rat only at the HDT of 900 mg/kg/day. The
corresponding maternal and developmental NOELs were established at
doses of 100 and 300 mg/kg/day, respectively in the rat. In the rabbit,
maternal toxicity was observed at the HDT of 240 mg/kg/day; no evidence
of developmental toxicity was present at 240 mg/kg/day.
There was no effect of triasulfuron on reproductive performance in
a 2 generation rat reproduction study conducted at doses of 1, 50 and
250 mg/kg/day. Maternal and fetal toxicity as indicated by decreased
body weight gain was noted at the HDT 250 mg/kg/day. The maternal and
developmental NOELs were 50 mg/kg/day.
Section 408 of the FFDCA provides that EPA may apply an additional
safety factor for infants and children in the case of threshold effects
to account for pre- and post-natal toxicity and the completeness of the
database. Based on the current toxicological data requirements, the
database relative to pre- and post-natal effects for children is
complete. Further, for triasulfuron,
the NOEL of 1.2 mg/kg/day from the mouse oncogenicity study, which was
used to calculate the RfD of 0.01 mg/kg/day, was approximately 50 times
lower than the developmental NOEL level from the rat multigeneration
reproduction study. There is no evidence to suggest that developing
organisms are more sensitive to the effects of triasulfuron than are
Using the conservative exposure assumptions described above and the
chronic toxicity NOEL of 1.2 mg/kg/day (RfD of 0.01 mg/kg/day),
Novartis has determined that the % of the RfD that will be utilized by
aggregate exposure to residues of triasulfuron is 3.98% for nursing
infants less than 1-year old, 15.43% for non-nursing infants, 10.91%
for children 1 to 6-years old and 7.34% for children 7 to 12-years old.
Therefore, based on the completeness and reliability of the toxicity
data and the conservative exposure assessment, Novartis concludes that
there is a reasonable certainty that no harm will result to infants and
children from aggregate exposure to triasulfuron residues.
F. International Tolerances
There are no Codex Alimentarius Commission (CODEX) maximum residue
levels (MRL's) established for residues of triasulfuron in or on raw
[FR Doc. 98-14160 Filed 5-28-98; 8:45 am]
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