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Triflusulfuron methyl (IR-4). August 8, 2001. Pesticide Tolerance Petition. Federal Register.


http://www.epa.gov/fedrgstr/EPA-PEST/2001/August/Day-08/p19756.htm


[Federal Register: August 8, 2001 (Volume 66, Number 153)]
[Notices]
[Page 41593-41597]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08au01-81]

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ENVIRONMENTAL PROTECTION AGENCY
[PF-1036; FRL-6795-4]
 
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 control number PF-1036, must be 
received on or before September 7, 2001.

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 
control number PF-1036 in the subject line on the first page of your 
response.

FOR FURTHER INFORMATION CONTACT: By mail: Shaja R. Brothers, 
Registration Division (7505C), Office of Pesticide Programs, 
Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460; telephone number: (703) 803-3194; e-mail address: 
brothers.shaja@epa.gov.

SUPPLEMENTARY INFORMATION:

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:

------------------------------------------------------------------------
                                                          Examples of
           Categories                 NAICS codes         potentially
                                                       affected entities
------------------------------------------------------------------------
Industry                          111                 Crop production
                                  112                 Animal production
                                  311                 Food manufacturing
                                  32532               Pesticide
                                                       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 
CONTACT.

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 
electronically, from the EPA Internet Home Page at http://www.epa.gov/. 
To access this document, on the Home Page select ``Laws and 
Regulations'' ``Regulation and Proposed Rules,'' and then look up the 
entry for this document under the ``Federal Register--Environmental 
Documents.'' You can also go directly to the Federal Register listings 
at http://www.epa.gov/fedrgstr/.
    2. In person. The Agency has established an official record for 
this action under docket control number PF-1036. 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 control number PF-1036 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: opp-docket@epa.gov, 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 PF-1036. 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 
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 version of the 
official record.

[[Page 41594]]

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 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 
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 
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 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: July 27, 2001.
Peter Caulkins,
Acting Director, Registration Division, Office of Pesticide Programs.

Summary of Petition

    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.

Interregional Research Project #4 (IR-4)

PP (0E6214)

    EPA has received a pesticide petition [0E6214]
from the 
Interregional Research Project #4 (IR-4), 681 US Highway #1 South, 
North Brunswick, NJ 08902 proposing, pursuant to section 408(d) of the 
FFDCA, 21 U.S.C. 346a(d), to amend 40 CFR part 180.492 by establishing 
a tolerance for residues of triflusulfuron methyl in or on the raw 
agricultural commodity chicory (root) at 0.05 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 support granting of the petition. 
Additional data may be needed before EPA rules on the petition. This 
notice includes a summary of the petition prepared by Dupont, E.I. du 
Pont Nemours and Company, Agricultural Products, Wilmington, DE 19898.

A. Residue Chemistry

    1. Plant metabolism. The metabolism and chemical nature of residues 
of triflusulfuron-methyl in plants is adequately understood.
    2. Analytical method. High performance liquid chromatograph (HPLC) 
is the analytical method acceptable for determining residues of 
triflusulfuron-methyl in plants, and is available for enforcement 
purposes.
    3. Magnitude of residues. The magnitude of residue data for 
triflusulfuron methyl in/on chicory is adequately understood. Residue 
field trials conducted in Washington and California have shown that the 
maximum residues in the raw agricultural commodity chicory and the 
processed commodities dry pulp and inulin were below the limit of 
detection (0.016 ppm). A tolerance for residues of triflusulfuron-
methyl in chicory root at 0.05 ppm is consistent with the tolerances 
proposed by Du Pont for sugar beet roots and tops at 0.05 ppm.

B. Toxicological Profile

    1. Acute toxicity. Based on EPA criteria, technical triflusulfuron 
methyl is in acute toxicity Category IV for oral and inhalation routes 
of exposure, and for dermal irritation. Triflusulfuron methyl is in 
acute toxicity Category III for dermal toxicity and for eye irritation. 
Acute oral toxicity in rats LD50 5,000 mg/kg; acute dermal 
toxicity in rabbits LD50 2,000 mg/kg; and acute inhalation 
toxicity in rats LC50 5.1 mg/L. Primary eye irritation in 
rabbits, non-irritant primary dermal irritation in rabbits, non-
irritant dermal sensitization in guinea pigs, and non-sensitizer acute 
neurotoxicity no observed adverse effect level (NOAEL)= 2,000 mg/kg/day 
highest dose tested (HDT).
    2. Genotoxicity. Mutagenicity data for technical triflusulfuron 
methyl include a reverse mutation assay (Ames Test) which was negative 
at concentrations up to 1,000 mg/plate, the HDT; a Salmonella 
typhimurium plate incorporation assay which was negative at 
concentrations up to 3,000 mg/plate, HDT; and a Chinese 
hamster ovary/hypoxanthine-guanine (CHO/HPRT) assay which was negative 
at concentrations up to 2,000 mg/kg/day, HDT. A chromosomal aberration/
human lymphocyte assay was positive in the presence of metabolic 
activation at concentrations greater than or equal to 1,500 
mg/mL. A second chromosomal aberration/human lymphocyte assay was 
positive in the presence of metabolic activation at concentrations of 
2,000 mg/mL. Results in the absence of metabolic activation 
were inconclusive for both chromosomal aberration studies. The mouse 
bone marrow micronucleus test was negative at doses up to 5,000 mg/kg, 
HDT. In three Salmonella typhimurium plate incorporation assays, 
metabolites of triflusulfuron methyl were negative up to 5,000 
mg/plate, HDT.
    3. Reproductive and developmental toxicity. In a 2-generation rat 
reproduction study, rats were fed dosages of 0, 0.588, 5.81, 44.0 and 
89.5 mg/kg/day (males) and 0, 0.764, 7.75, 58.0, and 115 mg/kg/days 
(females) with a reproductive toxicity NOAEL equal to or greater than 
89.5 and 115 mg/kg/day for males and females, respectively, based on 
the absence of reproductive

[[Page 41595]]

effects in rats at the HDT. The NOAEL for systemic toxicity was 5.81 
and 7.75 mg/kg/day for males and females, respectively based on 
decreased body weight/body weight gain (bwt/bwt gain) and food 
efficiency in males and females, and decreased weights of offspring 
from the F0 generation on days 14 and 21 post-partum at 44.0 
and 58.0 mg/kg/day in males and females, respectively. Technical 
triflusulfuron methyl was evaluated for developmental toxicity 
potential in rats and rabbits. Rats were fed dosages of 0, 30, 120, 
350, and 1,000 mg/kg/day with a developmental NOAEL equal to or greater 
than 1,000 mg/kg/day (HDT) and a maternal toxicity NOAEL of 120 mg/kg/
day with a lowest observed adverse effect level (LOAEL) of 350 mg/kg/
day based on reduced body weight gain in the 350 and 1,000 mg/kg/day 
animals, reduced food consumption in the 1,000 mg/kg/day animals and 
lower food efficiency in the 350 and 1,000 mg/kg/day. Rabbits were fed 
dosages of 0, 15, 90, 270, and 800 mg/kg/day with a NOAEL for 
developmental toxicity of 90 mg/kg/day with a LOAEL of 270 mg/kg/day 
based on the increase in abortions and a decrease in mean fetal body 
weight (bwt). The NOAEL for maternal toxicity is 90 mg/kg/day with a 
LOAEL of 270 mg/kg/day based on the maternal death and abortions, and 
increase in clinical signs noted in the mid-high and high dose groups, 
decreased food efficiency and increased post mortem finding describing 
gastrointestinal effects.
    4. Subchronic toxicity. The subchronic toxicity of technical 
triflusulfuron methyl was evaluated in rabbits, rats, and dogs. In a 
21-day dermal toxicity study with rabbits fed dosages of 50, 300, or 
1,000 mg/kg/day, the systemic toxicity NOAEL was equal to or greater 
than 1,000 mg/kg/day for males and females. The dermal toxicity NOAEL 
was equal to or greater than 1,000 mg/kg/day for males and females.
    Two 90-day studies were conducted in the rat. In one study, rats 
were fed dosages of 6.2, 127, 646, or 965 mg/kg/day (males) or 7.54, 
150, 774, or 1,070 mg/kg/day (females). Triflusulfuron methyl exhibited 
subchronic toxicity at dietary concentrations of 2,000 ppm (127 and 150 
mg/kg/day for males and females) or greater in the form of decreased 
body weights, decreased body weight gains, decreased food efficiency, 
increased mean relative liver weights, and regenerative anemia. The 
NOAEL was 6.2 mg/kg/day (males) and 7.54 mg/kg/day (females).
    In another study, rats were fed dosages of 6.56, 133, 658, or 1,036 
mg/kg/day (males) or 7.71, 153, 783, or 1,124 mg/kg/day (females). 
Triflusulfuron methyl showed subchronic toxicity at dietary 
concentrations of 2,000 ppm (133 and 153 mg/kg/day for males and 
females) or greater in the form of decreased body weight, decreased 
body weight gain, decreased food efficiency, and increased mean liver 
weights. The NOAEL was 6.56 mg/kg/day (males) and 7.71 mg/kg/day 
(females).
    A subchronic neurotoxicity study with rats fed dosages of 0, 6.1, 
46.1, 92.7, or 186.2 mg/kg/day (males) or 7.1, 51.6, 104.1, or 205.2 
mg/kg/day (females), resulted in a NOAEL of 92.7 (males) and 7.1 mg/kg/ 
day (females). This was based on decreased body weight/body weight gain 
at the LOAEL of 186.2 mg/kg/day (males) and 51.6 mg/kg/day (females).
    In another 90-day subchronic study, dogs were fed dosages of 3.87, 
146.1, or 267.6 mg/kg/day (males) or 3.72, 159.9, or 250.7 mg/kg/day 
(females). Triflusulfuron methyl was found to be hepatotoxic at 4,000 
ppm (146.1 mg/kg/day males and 159.9 mg/kg/day females), and greater 
elevated hepatic enzyme levels and postmortem evidence, including 
elevation in liver weights and microscopic evidence of bile stasis. 
Other microscopic findings considered to be treatment related were 
testicular atrophy and decreased testicular weights and 
hypercellularity of the sternal and femoral bone marrow, with a 
corresponding increase in reticulocyte and leukocyte counts seen in the 
high-dose males and females. Based on the microscopic findings in the 
liver and testes of the 4,000 ppm and greater treated animals, the 
NOAEL was 3.87 mg/kg/day (males) and 3.72 mg/kg/day (females).
    5. Chronic toxicity. The chronic toxicity of technical 
triflusulfuron methyl was evaluated in dogs, mice, and rats. In a 1-
year oral toxicity study with dogs fed dosages of 1.0, 26.9, 111.6 mg/ 
kg/day (males) and 1.2, 27.7, and 95.5 mg/kg/day (females), the NOAEL 
for males was 26.9 mg/kg/day; this was based on increases in alkaline 
phosphatase, liver weight, and incidence of minimal centrilobular 
hypertrophy at the LOAEL of 111.6. For females, the NOAEL was 27.7 mg/ 
kg/day; this was based on increased liver weight and increased 
incidence of minimal centrilobular hepatocellular hypertrophy at the 
LOAEL of 95.5 mg/kg/day.
    In an 18-month carcinogenicity study, mice were fed dosages of 
1.37, 20.9, 349, and 1,024 mg/kg/day (males) and 1.86, 27.7, 488, and 
1,360 mg/kg/day (females). Male mice had statistically significant 
positive trends for hepatocellular adenomas and for combined adenoma/
carcinoma (driven entirely by adenomas) at 349 and 1,024 mg/kg/day. 
These increases were not significant in pair-wise comparisons with 
control groups and were determined not to be carcinogenic effects by 
the Carcinogenicity Peer Review Committee (CPRC). The NOAEL was based 
on body and organ weight effects and was 20.9 mg/kg/day (males) and 
27.7 mg/kg/day (females). In the combined chronic toxicity/
carcinogenicity study, rats were fed dosages of 0, 0.406, 4.06, 30.6, 
and 64.5 mg/kg/day (males) and 0, 0.546, 5.47, 41.5, and 87.7 mg/kg/day 
(females). Male rats have a significant increasing trend and 
significant differences in pair-wise comparisons of the 30.6 and 64.5 
mg/kg/day dose groups with controls for interstitial cell adenomas. 
This effect was determined to be a carcinogenic effect by the CPRC. No 
carcinogenic effects were noted in females up to and including 87.7 mg/
kg/day HDT. The LOAEL for chronic toxicity is 30.6 mg/kg/day (males) 
and 41.5 (females) based on decreased body weight and body weight gain, 
alternations in the hematology parameters (males predominately) and an 
increased incidence of interstitial cell hyperplasia in males. The 
NOAEL for chronic toxicity is 4.06 mg/kg/day (males) and 5.47 mg/kg/day 
(females). This value is adjusted to the lowest concentration level of 
the chemical at this dosage (60%), resulting in NOAELs of 2.44 mg/kg/
day (males) and 3.28 mg/kg/day (females).
    6. Animal metabolism. For triflusulfuron methyl, in both the rat 
and the goat, a majority of the administrated dose was excreted in 
feces and urine. The biotransformation pathway for triflusulfuron 
methyl in the rat and the goat was similar. The major pathway was 
demethylation of the dimethylamino substituent on the triazine ring. 
The intermediate hydroxylated metabolite was also present. The 
secondary biotransformation pathway was clevage of the sulfonylurea 
bridge to form methyl saccharin, N-desmethyl triazine amine and N,N-
bis-desmethyl triazine amine. In the lactating goat, triflusulfuron 
methyl was not excreted to any appreciable level in the milk. Levels of 
the ester carbonyl-derived residues were generally below the limit of 
reliable measurement ( 0.0006 mg equivalent triflusulfuron 
methyl/mL) and triazine-derived residues reached a daily level of about 
0.001 ppm. Therefore, the metabolic pathways in rats and lactating 
goats were very

[[Page 41596]]

similar. There were no significant plant metabolites of triflusulfuron 
methyl that were not found in the rat or goat metabolism studies. In 
the unlikely event that triflusulfuron methyl were to enter the 
livestock diet, triflusulfuron methyl and its metabolites would be 
rapidly excreted and would not accumulate in meat, meat by-products, or 
milk.
    7. Metabolite toxicology. The approximate lethal dose (ALD) of the 
degradation product, N,N-bis-desmethyl triazine amine, in male rats was 
450 mg/kg/day. Rats were fed dose rates of 200, 300, 450, 670, 1,000, 
and 2,300 mg/kg of triflusulfuron methyl. Deaths occurred up to test 
day 7 in rats dosed at 450 mg/kg body weight and above. Clinical signs 
of toxicity were observed in lethally and nonlethally dosed rats. In an 
in vitro gene mutation study, N,N,-bis-desmethyl triazine amine was not 
mutagenic in Salmonella typhimurium up to a dose of 5,000 mg/
plate. For the degradation product, triazine amine, the ALD in male 
rats was 670 mg/kg/day. The test substance dose was 200, 300, 450, 670, 
1,000, or 2,300 mg/kg. Deaths occurred up to test day 4 in rats dosed 
at 670 mg/kg and above. Clinical signs of toxicity were observed in 
lethally and nonlethally dosed animals. In an in vitro gene mutation 
study, triazine amine was not mutagenic in Salmonella typhimurium up to 
a dose of 5,000 mg/plate.
    8. Endocrine disruption. No special studies investigating potential 
estrogenic or other endocrine effects of methyl have been conducted. 
However, the standard battery of required toxicology studies have been 
completed. These include an evaluation of the potential effects on 
reproduction and development, and an evaluation of the pathology of the 
endocrine organs following repeated or long-term exposure to doses that 
far exceed likely human exposures. Based on these studies there is no 
evidence to suggest that triflusulfuron methyl has an adverse effect on 
the endocrine system.

C. Aggregate Exposure

    1. Dietary exposure--i. Food. The acute dietary exposure was 
estimated for triflusulfuron methyl using the Dietary Exposure 
Evaluation Model (DEEM) (version 6.73) for a number of subpopulation 
groups. An acute Tier I dietary analysis was based upon the residues 
for sugar beet (root) at 0.05 ppm and sugar beet (top) at 0.05 ppm. The 
acute reference dose (aRfD) is 0.9 mg/kg bwt/day (based upon a NOAEL of 
90 mg/kg bwt/day and a 100-fold safety factor). For triflusulfuron 
methyl, the predicated exposure for the U.S. population was 0.00460 mg/
kg bwt/day (0.05 % of the aRfD) at the 95th percentile. The 
subpopulation with the highest predicted exposure was the non-nursing 
infants subgroup with an exposure of 0.00166 mg/kg bwt/day (0.19% of 
the aRfD) at the 95th percentile. Because the predicted exposures, 
expressed as percentages of the aRfD, are well below 100%, there is 
reasonable certainty that no acute effects would result from dietary 
exposure to triflusulfuron methyl.
    The chronic dietary exposure was estimated for triflusulfuron 
methyl using the DEEM (version 6.74) for a number of subpopulation 
groups. A chronic Tier I dietary analysis was based upon residues for 
sugar beet (root) at 0.05 ppm and sugar beet (top) at 0.05 ppm. The 
chronic Reference dose (RfD) is 0.024 mg/kg bwt/day (based upon a NOAEL 
of 2.44 mg/kg bwt/day and a safety factor of 100). The estimated 
exposure for the U.S. population was 0.000146 mg/kg bwt/day (0.6% of 
the RfD). For the subpopulation with the highest level of exposure 
(non-nursing infants), the exposure was 0.000433 mg/kg bwt/day (1.8% of 
the chronic reference dose (cRfD)). Because the predicted exposures, 
expressed as percentages of the cRfD, are well below 100%, there is 
reasonable certainty that no chronic effects would result from dietary 
exposure to triflusulfuron methyl. Even though very conservative 
assumptions were made in predicting acute and chronic exposures to 
triflusulfuron methyl, the predicted exposures expressed as percentages 
of the cRfD and aRfD values were found to be well within the acceptable 
range.
    ii. Drinking water. Based on the available environmental studies 
conducted with triflusulfruon methyl, DuPont concludes that there is no 
anticipated exposure to residues of triflusulfuron methyl in drinking 
water. In addition, there is no established maximum concentration level 
(MCL) for residues of triflusulfuron methyl in drinking water.
    2. Non-dietary exposure. Triflusulfuron methyl is not registered 
for any use that could result in non-occupational or non-dietary 
exposure to the general population.

D. Cumulative Effects

    Triflusulfuron methyl belongs to the sulfonylurea class of crop 
protection chemicals. Other structurally similar compounds in this 
class are registered herbicides. However, the herbicidal activity of 
sulfonylureas is due to the inhibition of acetolacate synthase (ALS), 
an enzyme found only in plants. This enzyme is part of the biosynthesis 
pathway leading to the formation of branched chain amino acids. Animals 
lack ALS and this biosynthetic pathway. This lack of ALS contributes to 
the relatively low toxicity of sulfonylurea herbicides in animals. 
There is no reliable information that would indicate or suggest that 
triflusulfuron methyl has any toxic effects on mammals that would be 
cumulative with those of any other chemical.

E. Safety Determination

    1. U.S. population. Based on the completeness and reliability of 
the toxicology data base and using the conservative assumptions 
presented earlier, EPA has established a cRfD of 0.024 mg/kg/day. This 
was based on the NOAEL for the 2-year chronic rat study (2.44 mg/kg/
day) and a 100-fold safety factor. It has been concluded that the 
aggregate exposure was 0.6% of the cRfD. Generally, exposures below 
100% of the cRfD are of no concern because it represents the level at 
or below which daily aggregate exposure over a lifetime will not pose 
appreciable risk to human health. Thus, there is reasonable certainty 
that no harm will result from aggregate exposures to triflusulfuron 
methyl residues.
    2. Infants and children. In assessing the potential for additional 
sensitivity of infants and children to residues of triflusulfuron 
methyl, data from the previously discussed developmental and multi-
generation reproductive toxicity studies were considered. Developmental 
studies are designed to evaluate adverse effects on the developing 
organism resulting from pesticide exposure during prenatal development. 
Reproduction studies provide information relating to reproductive and 
other effects on adults and offspring from the prenatal and postnatal 
exposures to the pesticide. The studies with triflusulfuron methyl 
demonstrated no evidence of developmental toxicity at exposures below 
those causing maternal toxicity. This indicates that developing animals 
are not more sensitive to the effects of triflusulfuron methyl 
administration than adults.
    FFDCA section 408 provides that EPA may apply an additional 
uncertainty factor for infants and children in the case of threshold 
effects to account for prenatal and postnatal toxicity and the 
completeness of the data base. Based on current toxicological data 
requirements, the data base for triflusulfuron methyl relative to 
prenatal and postnatal effects for children is complete. In addition, 
the NOAEL of 2.44 mg/kg/day in the chronic rat study (and upon which 
the cRfD is based) is much lower than the

[[Page 41597]]

NOAELs defined in the reproduction and developmental toxicology 
studies. The sub-population with the highest level of exposure was non-
nursing infants, where exposure was  1.8% of the cRfD. Based on these 
conservative analyses, there is reasonable certainty that no harm will 
result to infants and children from aggregate exposures to 
triflusulfuron methyl.

F. International Tolerances

    There are no Codex Maximum Residue Levels established for 
triflusulfuron methyl.
[FR Doc. 01-19756 Filed 8-7-01; 8:45 am]
BILLIBG CODE 6560-50-S