PMEP Home Page --> Pesticide Active Ingredient Information --> Herbicides, Growth Regulators and Desiccant --> sesone to vernolate (Vernam) --> triasulfuron (Amber) --> triasulfuron (Amber) Pesticide Petition Filing 5/98

triasulfuron (Amber) Pesticide Petition Filing 5/98


[Notices]               
[Page 29401-29409]
>From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr29my98-49]

-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

[PF-806; FRL-5791-2]

 
Monsanto Company; Pesticide Tolerance Petitions Filing

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

-----------------------------------------------------------------------

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: tompkins.james@epamail.epa.gov.
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:
    opp-docket@epamail.epa.gov


    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 
requirements.

    Dated: May 14, 1998.

James Jones,

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.

PP 3F4225

    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.

[[Page 29406]]

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 
levels.
    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 
mechanism exists.

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,

[[Page 29407]]

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 
adults.
    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 
agricultural commodities.

[FR Doc. 98-14160 Filed 5-28-98; 8:45 am]
BILLING CODE 6560-50-F