[Federal Register Volume 67, Number 157 (Wednesday, August 14, 2002)]
[Notices]
[Pages 52990-52996]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-20230]


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ENVIRONMENTAL PROTECTION AGENCY

[OPP-2002-0175; FRL-7191-7]


Notice of Filing Pesticide Petitions to Establish Tolerances 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 pesticide 
petitions 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-2002-0175, must be 
received on or before September 13, 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-2002-0175 in the subject line on the first page of your 
response.

FOR FURTHER INFORMATION CONTACT: By mail: Hoyt Jamerson, Registration 
Support Branch, Registration Division (7505C), Office of Pesticide 
Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460; telephone number: (703) 308-9368; e-mail address: 
[email protected].

SUPPLEMENTARY INFORMATION:

[[Page 52991]]

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'' 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 ID number OPP-2002-0175. 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-2002-0175 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 protected], 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 ID number OPP-2002-0175. 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. 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 
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 pesticide petitions 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 the petitions contain 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 petitions. Additional data 
may be needed before EPA rules on the petitions.

List of Subjects

    Environmental protection, Agricultural commodities, Feed additives, 
Food additives, Pesticides and pests, Reporting and recordkeeping 
requirements.


[[Page 52992]]


    Dated: July 31, 2002.
Peter Caulkins,
Acting Director, Registration Division, Office of Pesticide Programs.

Summary of Petitions

    The 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 summaries verbatim without 
editing them in any way. The summaries 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 Number 4 (IR-4)

Dow Agro Sciences LLC

PP 1E6227, 1E6241, 1E6283, 1E6291, 1E6320, 1E6329, 1E6333, 1E6334, 
1E6335, 1E6399, and 1E6340

    EPA has received pesticide petitions (PP) (1E6227, 1E6241, 1E6283, 
1E6291, 1E6320, 1E6329, 1E6333, 1E6334, 1E6335, 1E6399 and 1E6340) from 
the Interregional Research Project Number 4 (IR-4), P.O. Box 231, 
Rutgers University, New Brunswick, NJ 08903 and PP 4F4379 from Dow Agro 
Sciences LLC, Indianapolis, IN 46268, 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 to establish tolerances for 
clopyralid in or on the raw agricultural commodities as follows:
    1. PP 1E6227 proposes a tolerance for flax seed at 3.0 part per 
million (ppm).
    2. PP 1E6241 proposes a tolerance for strawberry at 1.0 ppm.
    3. PP 1E6283 proposes a tolerance for hop, dried cones at 5.0 ppm.
    4. PP 1E6291 proposes tolerances for rapeseed seed, rapeseed 
forage, canola seed, mustard seed, and crambe seed at 3 ppm, and canola 
meat at 6.0 ppm.
    5. PP 1E6320 proposes a tolerance for spinach at 5.0 ppm.
    6. PP 1E6329 proposes a tolerance for the stone fruit group at 0.5 
ppm.
    7. PP 1E6333 proposes tolerances for garden beet tops at 3.0 ppm 
and garden beet roots at 4.0 ppm.
    8. PP 1E6334 proposes a tolerance for mustard greens at 5.0 ppm.
    9. PP 1E6335 proposes tolerances for turnip roots at 1.0 ppm and 
turnip greens at 4.0 ppm.
    10. PP 1E6340 proposes a tolerance for cranberry at 4 ppm.
    11. PP 4F4379 proposes tolerances for sweet corn, kernel plus cob 
with husks removed at 1.0 ppm, sweet corn forage at 7.0 ppm, sweet corn 
stover at 10.0 ppm, pop corn grain at 1.0 ppm, pop corn stover at 10.0 
ppm, liver of cattle, goat, horse, and sheep at 3.0 ppm, meat 
byproducts, except liver, of cattle, goat, horse and sheep at 36.0 ppm, 
and milk at 0.2 ppm.
    12. PP 1E3999 proposes a tolerance for the Brassica, head and stem, 
subgroup at 2.0 ppm.
    EPA has determined that the petitions contain 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 
petitions. Additional data may be needed before EPA rules on the 
petitions. This notice includes a summary of the petition prepared by 
Dow Agro Sciences LLC, Indianapolis, IN 46268.

A. Residue Chemistry

    1. Plant metabolism. The metabolism in plants is adequately 
understood. No metabolites of significance were detected in plant 
metabolism studies.
    2. Analytical method. There is a practical analytical method for 
detecting and measuring levels of clopyralid in or on food with a limit 
of quantitation (LOQ) of 0.05 ppm that allows monitoring of food with 
residues at or above the levels set in these tolerances. EPA has 
provided information on this method to FDA. The method is available to 
anyone who is interested in pesticide residue enforcement.
    3. Magnitude of residues. For flax, magnitude of residue data on 
flax in Canada were used. The maximum residue limits for clopyralid in 
Canada are 0.2 ppm for flax. Trial sites conducted in Canada include 
Manitoba and Alberta which borders North Dakota and Minnesota. 
Clopyralid was applied at 150 to 300 g ai/ha (0.13 to 0.27 lb ai/acre). 
The maximum combined residue was 0.22 ppm.
    For mustard greens, magnitude of residue data were collected from 
field trials conducted in New Jersey, California, South Carolina, 
Texas, Florida, Michigan, and Tennessee. Each of eight field trial 
sites consisted of one untreated control plot and one treated plot. The 
treated plots received one application of the test substance at a rate 
of approximately 0.187 lb ai/acre. Marketable greens (mustard plants) 
were collected approximately 30 days following the application. In 
treated greens (mustard) samples, clopyralid residues ranged from 0.48 
to 4.4 ppm.
    For turnip roots and tops, magnitude of residue data were collected 
from field trials conducted in Tennessee, North Carolina, Texas, 
Georgia, Wisconsin, and California. Each of the six field trial sites 
consisted of one untreated control plot and one treated plot. The 
treated plots received one application of the test substance at a rate 
of approximately 0.187 lb ai/acre. At the North Carolina trial, a 
banded application was made to simulate regional practices; broadcast 
applications were made at the five remaining trials. Marketable turnip 
tops and roots were collected approximately 15 days and 30 days 
following the application, respectively. In treated tops samples, 
clopyralid residues ranged from 0.64 to 3.2 ppm. Clopyralid residues in 
treated roots samples ranged from 0.059 to 0.56 ppm.
    For garden beet, magnitude of residue data were collected from 
field trials conducted in Florida, Michigan, New York, Texas, 
Wisconsin, and Washington. Each of the seven field trial sites 
consisted of one untreated control plot and one treated plot. The 
treated plots received one application of the test substance at a rate 
of approximately 0.187 lb ai/acre. Marketable beet (garden) roots and 
tops were collected approximately 30 days following the application, 
respectively. In treated tops samples, clopyralid residues ranged from 
0.36 to 2.8 ppm. Clopyralid residues in treated roots samples ranged 
from 0.71 to 3.0 ppm.
    For stone fruit, cherry field trials were conducted in Michigan, 
Washington, and New Jersey. Cherry plots were treated once by a 
broadcast application directed to the orchard floor with clopyralid at 
approximately 0.5 lb ai/acre. Samples were taken 21 to 31 days after 
the last treatment. All cherries were pitted prior to freezing. Peach 
trials were conducted in New Jersey, Michigan, North Carolina, and 
California. One application of clopyralid at approximately 0.5 lb ai/
acre was made to a band on each side of the trees in the treated plots. 
The fruit in the New Jersey trials matured quickly and were harvested 
after 20 to 21 days. In North Carolina, the peaches were harvested 
after 20 days because insect and disease pressure threatened to ruin 
the crop. All peaches were pitted prior to freezing. Plum trials were 
conducted in New Jersey, Washington, and California. One application of 
clopyralid at approximately 0.5 lb ai/acre was made to a bank on each 
side of the trees in the treated plots. The fruit in one California 
trial matured quickly and was harvested after 21 days. The other 
California trial included collection of both fresh and dried plums. All 
plums were pitted prior to freezing or drying.

[[Page 52993]]

    No detectable residues of clopyralid were found in any of the 
untreated peach samples. The treated samples from California and one of 
the treated samples from North Carolina also had no detectable 
residues. The residues in the other samples were no higher than 0.35 
ppm. No detectable residues of clopyralid were found in any of the 
untreated or treated cherries in this study. No detectable residues of 
clopyralid were found in any of the untreated plums or dried plums. No 
detectable residues of clopyralid were found in the treated plum 
samples from California. The treated plum samples from New Jersey and 
Washington had residues in the range 0.05 to 0.41 ppm. The dried plum 
samples had residues in the range 0.16 to 0.19 ppm.
    For hops, magnitude of residue data were collected from field 
trials conducted in Oregon and Washington. Each field trial site 
consisted of one untreated control plot and one treated plot. The 
treated plots received two applications of the test substance at a rate 
of 0.38 lb ai/acre + 5%. All applications were made post-emergence, 
directed, 21 to 22 days apart. Dried hop cone samples were collected 27 
to 32 days following the final application. Residue concentrations from 
treated samples ranged from a high 4.14 ppm to a low 0.3 ppm. All 
residues found in treated samples fell between the highest and lowest 
concentrations tested in method validation, 0.1 ppm and 0.5 ppm. None 
of the untreated samples were found to contain clopyralid above the 
instrumental detection limit of 0.08 ppm.
    For cranberry, field trials were conducted in Maine, New Jersey, 
Oregon, Washington, and Wisconsin. Clopyralid was broadcast onto 
fruiting cranberry vines at approximately 0.25 lb ai/acre to the 
treated plots, twice, at an interval of 13 to 16 days. Treated and 
untreated cranberries were harvested 44 to 51 days after the second 
application and stored frozen. No detectable residues of clopyralid 
were found on untreated cranberries from any of the field trials. 
Residues on treated samples were in the range 0.88 to 3.1 ppm.
    For spinach, field trials were conducted in Texas, New York, 
California, Tennessee, South Carolina, and Georgia. Clopyralid was 
applied once at a rate of 0.092 to 0.290 lb ai/acre 20 to 22 days 
before harvest. Spinach was harvested and stored frozen. Residues on 
treated samples were in the range 0.056 to 3.8 ppm.
    For strawberry, field trials were conducted in Oregon, California, 
North Carolina, New Jersey, and Michigan. Clopyralid applied foliar 
post-emergence in the late summer or early fall at a use rate of 
approximately 0.25 lb ai/acre, followed by a second application of 
approximately 0.125 lb ai/acre at 28 to 31 days before harvest resulted 
in residues of clopyralid ranging from 0.10 to 0.505 ppm. When applied 
at 0.50 lb ai/acre followed by a second application of approximately 
0.25 lb ai/acre at 28 to 31 days before harvest resulted in residues of 
clopyralid ranging from 0.295 to 1.61 ppm.
    For sweet corn, field trials were conducted in California, Georgia, 
Illinois, Michigan, Minnesota, North Carolina, New York, Ohio and 
Pennsylvania. Clopyralid was applied once as a post-emergent broadcast 
spray with water as a carrier at the rate of 0.66 to 0.70 percent 
treated (pt)/acre (0.25 to 0.26 lb ai/acre). The application was made 
when the corn was 12 to 18 inches in height and prior to tasseling. The 
ears were removed before the remaining plant (forage) was chopped. 
Residues were detected at the following ppm ranges: Grain, 0.087-0.12; 
forage, 0.34-2.0; ears (K + CWHR) 0.029-0.23; cannery waste, no 
residues were detected above the limit of quantitation (LOQ) of the 
method.
    For popcorn, field trials were conducted in Indiana, Iowa, Nebraska 
and Ohio. Clopyralid was applied once as a post-emergent broadcast 
spray with water as the carrier at the rate of 0.67 pt/acre (0.25 lb 
ai/acre). The application was made when the popcorn was 22 to 24 inches 
in height. Green forage was collected when kernels were in the milk 
stage (i.e., at a pre-harvest interval of 45 to 55 days). Kernels and 
fodder were collected at normal harvest (i.e., at pre-harvest intervals 
of 78 to 129 days). Residues were detected at the following ppm ranges: 
Grain, 0.03-0.91; fodder, no detectable residues above the LOQ of the 
method - 0.60; forage, 0.14-1.2.
    In the magnitude of residue field studies for canola, crambe, and 
mustard seed, the first study had three field trials, one each in 
Georgia, South Dakota, and Washington. Each field trial site consisted 
of one untreated control plot and one treated plot. The treated plots 
received one broadcast application of the test substance 70 to 74 days 
before harvest. The test substance was applied to the treated plot at a 
rate of 0.211 lb ai/acre to 0.256 lb ai/acre. Residues of clopyralid 
detected in the field treated samples ranged from 0.42 to 1.32 ppm. The 
second field study had three field trials, one each in Georgia, South 
Dakota, and Washington. Again, each field trial site consisted of one 
untreated control plot and one treated plot. The treated plots received 
one broadcast application of the test substance 48 to 49 days before 
harvest. The test substance was applied to the treated plot at a rate 
of 0.231 lb ai/acre to 0.255 lb ai/acre. Two additional samples from 
the Washington trial (one treated and one untreated) were sent for 
processing into oil and meal. Residues of clopyralid detected in the 
field treated samples of canola seed ranged from >0.05 to 1.86 ppm. 
There were no detectable residues of clopyralid in either the canola 
oil or canola meal samples.

B. Toxicological Profile

    1. Acute toxicity. Clopyralid has low acute toxicity. The rat oral 
LD50 is 5,000 milligrams/kilogram (mg/kg) or greater for 
males and females. The rabbit dermal LD50 is greater than 
2,000 mg/kg and the rat inhalation LC50 is greater than 1.0 
mg/L air (the highest attainable concentration). In addition, 
clopyralid is not a skin sensitizer in guinea pigs and is not a dermal 
irritant. Technical clopyralid is an ocular irritant, but ocular 
exposure to the technical material would not normally be expected to 
occur to infants or children or the general public. End use 
formulations of clopyralid have similar low acute toxicity profiles and 
most have low ocular toxicity as well.
    2. Genotoxicty. Clopyralid is not genotoxic. The following studies 
have been conducted and all were negative for genotoxic responses: Ames 
bacterial mutagenicity assay (with and without exogenous metabolic 
activation); host-mediated assay in vivo cytogenetic test, rat; in vivo 
cytogenetic test, mouse; in vivo dominant lethal test, rat; in vitro 
unscheduled DNA synthesis assay in primary rat hepatocyte cultures; in 
vitro mammalian cell gene mutations assay in Chinese hamster ovary cell 
cultures (with and without exogenous metabolic activation).
    3. Reproductive and developmental toxicity. Developmental toxicity 
was studied using rats and rabbits. The developmental study in rats 
resulted in a developmental no observed adverse effect level (NOAEL) of 
>250 mg/kg/day (a maternally toxic dose) and a maternal toxicity NOAEL 
of 75 mg/kg/day. A 1974 study in rabbits revealed no evidence of 
developmental or maternal toxicity at 250 mg/kg/day; thus, the 
developmental and maternal NOEL was >250 mg/kg/day. A more recent study 
in rabbits (1990) resulted in developmental and maternal NOAELs of 110 
mg/kg/day based on maternal toxicity at 250 mg/kg/day. Based on all of 
the data for clopyralid, there is no evidence of developmental toxicity 
at dose levels that do not result in maternal toxicity.

[[Page 52994]]

In a 2-generation reproduction study in rats, pups from the high dose 
group which were fed diets containing clopyralid had a slight reduction 
in body weight during lactation and an increase in liver weights in F1a 
and F1b weanlings. The NOAEL for parental systemic toxicity was 500 mg/
kg/day. There was no effect on reproductive parameters at >1,500 mg/kg/
day nor was there an adverse effect on the morphology, growth or 
viability of the offspring; thus, the reproductive NOAEL is >1,500 mg/
kg/day.
    4. Subchronic toxicity. The following studies have been conducted 
using clopyralid. In a rat 90-day feeding study, Fischer 344 rats were 
fed diets containing clopyralid at doses of 5, 15, 50, or 150 mg/kg/day 
with no adverse effects attributed to treatment. In a second study, 
Fischer 344 rats were fed diets containing clopyralid at doses of 300, 
1,500, and 2,500 mg/kg/day. Effects at the highest doses were decreased 
food consumption accompanied by decreased body weights and weight gains 
in both males and females. Slightly increased mean relative liver and 
kidney weights were noted in males of all doses and in females at the 
top two doses. Because there were no other effects, the kidney and 
liver weight effects were judged as being adaptive rather than directly 
toxic. The NOAEL was 1,500 mg/kg/day for males and females. The NOAEL 
was 300 mg/kg/day for females. In a mouse 90-day feeding study, B6C3F1 
mice were fed diets containing clopyralid at doses of 200, 750, 2,000, 
or 5,000 mg/kg/day. A slight decrease in body weight occurred at the 
top dose in both sexes. The liver was identified as the target organ 
based on slight increases in liver weights and minimal microscopic 
alterations at the higher dose levels. The liver changes were 
considered to be reversible and adaptive. The NOAEL for males was 2,000 
mg/kg/day and for females was 750 mg/kg/day. In a 180-day feeding 
study, beagle dogs were fed diets containing clopyralid at doses of 15, 
50, or 150 mg/kg/day; there were no adverse effects. In a second 
dietary study, dogs also were fed diets containing clopyralid at doses 
of 15, 50, or 150 mg/kg/day; the only effect was an increase in the 
mean relative liver weight in females at the 150 mg/kg/day. In a 21-day 
dermal study, clopyralid was applied by repeated dermal application to 
New Zealand White rabbits at dose levels up to 1,000 mg/kg/day. 
Treatment produced no systemic effects.
    5. Chronic toxicity. In a chronic toxicity and oncogenicity study, 
Sprague-Dawley rats were fed diets containing clopyralid at doses of 5, 
15, 50 or 150 mg/kg/day. The only effect was a trend toward a decreased 
body weight of female rats receiving the 150 mg/kg/day dose and the 
NOAEL was 50 mg/kg/day. In a second study, clopyralid was fed to 
Fischer 344 rats in the diet at doses of 15, 150, or 1,500 mg/kg/day. 
The effects were confined almost entirely to the 1,500 mg/kg/day dose 
groups and included slightly decreased food consumption and body 
weights, slightly increased liver and kidney weights and macroscopic 
and microscopic changes in the stomach. No tumorigenic response was 
present. The NOAEL for this study was 150 mg/kg/day. B6C3F1 mice were 
maintained for 2 years on diets formulated to provide targeted dose 
levels of 10, 500, or 2,000 mg/kg/day. The only evidence of toxicity 
was body weight depression in males dosed at 2,000 mg/kg/day. There was 
no evidence of tumorigenic response at any dose level. Based on the 
chronic toxicity data, EPA has established the reference dose (RfD) for 
clopyralid at 0.5 mg/kg/day. The RfD for clopyralid based on a 2-year 
chronic oncogenicity study in rats with a NOAEL of 50 mg/kg/day and an 
uncertainty (or safety) factor of 100.
    6. Carcinogenicity. Using Guidelines for Carcinogen Risk Assessment 
published September 24, 1986 (51 FR 33992), clopyralid would be 
classified as Group E for carcinogenicity (no evidence of 
carcinogenicity) based on the results of the carcinogenicity studies. 
There was no evidence of carcinogenicity in 2-year feeding studies in 
mice and rats at the dosage levels tested. The doses tested are 
adequate for identifying a cancer risk. Thus, a cancer risk assessment 
would not be appropriate.
    7. Animal metabolism. Disposition and metabolism of clopyralid were 
tested in male and female rats at a dose of 5 mg/kg (oral). The 
majority of a radioactive dose was excreted in 24 hours of all dose 
groups. Fecal elimination was minor. Detectable levels of residual 
radioactivity were observed in the carcass and stomach at 72 hours 
post-dose. High performance liquid chromotography (HPLC) and thin layer 
chromotography (TLC) analysis of urine and fecal extracts showed no 
apparent metabolism of clopyralid.
    8. Metabolite toxicology. There are no clopyralid metabolites of 
toxicological significance.
    9. Endocrine disruption. There is no evidence to suggest that 
clopyralid has an effect on the endocrine system.

C. Aggregate Exposure

    1. Dietary exposure. Acute dietary risk assessment is performed for 
a food-use pesticide if a toxicological study has indicated the 
possibility of an acute effect of concern occurring as a result of a 1-
day or single exposure. EPA has previously used a NOAEL of 75 mg/kg/day 
from a rat developmental toxicity study to assess risk from acute 
dietary exposure, which is also the value used for assessment of acute 
dietary risk in this analysis. An acute RfD of 0.75 mg/kg/day was 
calculated, based on a NOAEL of 75 mg/kg/day and an uncertainty factor 
of 100 (10 for interspecies extrapolation and 10 for intraspecies 
variation). The maternal NOAEL was 75 mg/kg/day based on decreased 
weight gain during gestation days 6-9. The developmental NOEL was >250 
mg/kg/day, indicating no additional sensitivity for developing young 
relative to adults. The acute RfD of 0.75 mg/kg/day was used to assess 
acute dietary risk for the general population, including infants and 
children.
    Chronic dietary exposure to clopyralid is possible due to the 
potential presence of clopyralid residue in certain foods and drinking 
water. Chronic dietary risk was evaluated using a chronic RfD of 0.5 
mg/kg/day, which is based on a NOAEL of 50 mg/kg/day from a chronic rat 
study along with an uncertainty factor of 100.
    Since there was no evidence of carcinogenicity in the toxicology 
studies, a cancer risk assessment is not applicable.
    i. Food. The dietary exposure assessment was based on all 
commodities with tolerances for clopyralid established at 40 CFR 
180.431 together with the following proposed tolerances: Sweet corn: 
3.0 ppm; popcorn: 3.0 ppm; canola: 3.0 ppm; flax seed: 0.3 ppm; hops: 
5.0 ppm; strawberries: 1.0 ppm; mustard seed: 3 ppm; mustard greens: 5 
ppm; stone fruits (crop group 12): 0.5 ppm; spinach: 5 ppm; garden-beet 
tops: 3 ppm; garden-beet roots: 4 ppm; turnip tops: 4 ppm; turnip 
roots: 1 ppm; and cranberry: 4 ppm. Crambe seed tolerance at 3 ppm is 
also requested, although it was not included within the residue file, 
since it is not considered by the Dietary Exposure Evaluation Model 
(DEEM) version 7.76 due to low cultivated area and low consumption 
patterns. The DEEM 7.76, which is produced by Novigen Sciences, Inc. 
and licensed to Dow AgroSciences, was used to estimate dietary 
exposure. This software used the food consumption data for the 1994-96 
USDA Continuing Surveys of Food Intake by Individuals (CSFII 1994-96).
    a. Acute. A Tier 1 acute dietary risk assessment was conducted with 
the conservative assumptions of 100% crop

[[Page 52995]]

treated and tolerance level residues for 108 crop commodities. Acute 
dietary risk was assessed using an acute RfD of 0.75 mg/kg/day. Even 
with conservative assumptions used in this analysis, acute dietary 
exposure was estimated to occupy only 3.97% of the acute RfD for the 
overall U.S. population, at the 95th percentile. Acute 
dietary exposure for children 1-6 years old, the population subgroup 
estimated to have the highest exposure, occupies only 6.91% of the 
acute RfD, at the 95th percentile. Adverse effects are not 
expected for exposures occupying 100% or less of the RfD. Therefore, 
acute exposure and risk from food is well within acceptable levels.
    b. Chronic. A Tier 1 chronic dietary exposure and risk was 
estimated with the conservative assumptions of 100% crop treated and 
tolerance level residues for all crops. The estimate of potential 
chronic exposure and risk is very conservative and estimated risk would 
be substantially reduced with further refinement to the exposure 
estimate. Even with the conservative assumptions used in this analysis, 
chronic exposure is estimated to occupy only 2.3% of the RfD for the 
general U.S. population. Chronic dietary exposure for children 1-6 
years old, the population subgroup estimated to have the highest 
exposure, occupies only 5.4% the chronic RfD. Therefore, chronic 
exposure and risk from food is well within acceptable levels.
    ii. Drinking water. There is no established Maximum Contaminant 
Level (MCL) or Health Advisory Level (HAL) for residues of clopyralid 
in drinking water. High-end potential drinking water concentrations of 
clopyralid were estimated for ground water and surface water using the 
Screening Concentration in Ground Water (SCI-GROW) and Generic Expected 
Environmental Concentration (GENEEC) models respectively. Both GENEEC 
and SCI-GROW are Tier I screening level models that provide very 
conservative Estimated Environmental Concentrations (EECs) of pesticide 
residue in surface water and ground water, respectively. The EECs of a 
pesticide in surface water and ground water can be compared to a 
Drinking Water Level of Comparison (DWLOC) as a surrogate estimate of 
exposure and risk. The DWLOC is the concentration of a pesticide in 
drinking water that would be acceptable as an upper limit in light of 
total aggregate exposure to that pesticide in food and from residential 
uses.
    The EEC of clopyralid in ground water according to SCI-GROW is 2 
mg/L. Based on GENEEC, the estimated peak and 56-day concentration of 
clopyralid in surface water is 27 mg/L. EPA has previously indicated 
that the 56-day value from GENEEC should be divided by 3 for comparison 
to short-term and chronic DWLOC values. Therefore, a surface water 
concentration of 9 mg/L was used for comparison to short-term and 
chronic DWLOCs.
    a. Acute. EPA has indicated that peak concentrations of a pesticide 
in surface water should be used in an acute assessment for comparison 
with DWLOC values. The peak surface water concentration of clopyralid 
was estimated to be 27 parts per billion (ppb) while the potential 
concentration in ground water was estimated to be 2 ppb. The DWLOC for 
acute exposure was based on an acute RfD of 0.75 mg/kg/day and was 
calculated to be 13,664 ppb and 8,853 ppb for the overall U.S. 
population and children 1-6 years old, respectively. Therefore, the 
acute DWLOC is substantially greater than estimated high-end 
concentrations of clopyralid in surface water or ground water, 
indicating that potential acute exposure and risk from drinking water 
is well within acceptable levels.
    b. Chronic. As indicated previously, EECs in ground water and 
surface water for chronic exposures were estimated at 2 ppb and 9 ppb, 
respectively. The chronic DWLOC was calculated based on a chronic RfD 
of 0.5 mg/kg/day and accounted for potential chronic exposure to 
clopyralid through residues in food. The chronic DWLOC for the general 
U.S. population and children 1-6 years old was calculated to be 17,100 
ppb and 4,740 ppb, respectively. Therefore, the chronic DWLOCs are 
substantially greater than estimated residue concentrations in surface 
water or ground water, indicating that chronic exposure and risk from 
drinking water is well with acceptable levels.
    2. Non-dietary exposure. Clopyralid is registered for residential 
use on turf. Therefore, there is potential for both residential 
applicator exposure and post-application reentry exposure. EPA 
previously determined that there was no dermal toxicity endpoint since 
no systemic toxicity was observed at the highest dose tested (HDT) in a 
rabbit dermal toxicity study. Therefore, a dermal risk assessment is 
not required for residential exposure. EPA previously selected a 
maternal NOAEL of 75 mg/kg/day from a rat developmental toxicity study 
for assessing risk from short-term residential exposure through oral 
and inhalation routes, which is also the value used in this assessment. 
Inhalation exposure for residential applicators as well as post-
application reentry exposure for children through incidental non-
dietary ingestion of clopyralid residues were estimated using default 
values given in EPA's SOPs for Residential Exposure Assessments. 
Clopyralid residues have been found to dissipate rapidly from 
turfgrass, having a half-life of approximately 1-day. Considering the 
rapid dissipation of residues from turf along with the labeled use 
pattern, residential exposure may occur over a short-term interval, but 
would not be expected over an intermediate-term interval. Therefore, a 
short-term residential risk assessment was conducted, but an 
intermediate-term assessment was not required.
    EPA has previously indicated that it is appropriate to aggregate 
chronic food and water exposure with short-term residential exposures 
for clopyralid. In addition to its use in assessment of risk from 
short-term residential exposure, the short-term NOAEL of 75 mg/kg/day 
was also used for assessing risk from dietary and drinking water 
exposure during a short-term interval. A Tier 1 estimate of aggregated 
exposure for adults from food and from inhalation for residential 
applicators resulted in a Margin of Exposure (MOE) of 6,800. 
Additionally, a short-term DWLOC for adults was calculated to be 25,800 
ppb. Aggregated exposure for children 1-6 years old from food and from 
incidental non-dietary ingestion of clopyralid residues from treated 
turf resulted in an MOE of 2,300. Additionally, a short-term DWLOC for 
children 1-6 years old was calculated to be 7,100 ppb. EPA has 
indicated that the EECs for chronic exposure through ground water and 
surface water may also be used for assessing short-term exposure and 
risk. Therefore, the short-term ground water and surface water EECs are 
2 ppb and 9 ppb, respectively. The minimum acceptable MOE was based on 
an uncertainty factor of 100. Since the short-term MOE for adults and 
children is well above 100 and DWLOCs are well above EECs for drinking 
water, aggregated short-term exposures are not expected to exceed a 
level of concern.

D. Cumulative Effects

    The potential for cumulative effects of clopyralid and other 
substances that have a common mechanism of toxicity was considered. The 
mammalian toxicity of clopyralid is well defined. However, no reliable 
information exists to indicate that toxic effects produced by 
clopyralid would be cumulative with those of any other chemical 
compound. Additionally, clopyralid does not appear to produce a toxic 
metabolite produced by other substances. Therefore, consideration of a 
common

[[Page 52996]]

mechanism of toxicity with other compounds is not appropriate at this 
time. Thus, potential exposures to clopyralid were considered only in 
an aggregate exposure assessment.

E. Safety Determination

    1. U.S. population. Using the conservative exposure assumptions 
previously described, acute dietary exposure to residues of clopyralid 
from current and proposed uses was estimated to occupy only 3.97% of 
the RfD for the general U.S. population. EPA generally has no concern 
for exposures below 100% of the RfD since the RfD represents the level 
at or below which exposure will not pose appreciable risks to human 
health. Additionally, the acute DWLOC was calculated to be over 1,500 
fold greater than potential clopyralid residue in drinking water as 
predicted by conservative screening-level models. A conservative Tier 1 
assessment indicated that chronic dietary exposure would occupy only 
2.3% of the chronic RfD for the general U.S. population. Additionally, 
the chronic DWLOC was calculated to be over 1,900 fold greater than 
surface water or ground water EECs developed by screening-level models. 
A Tier 1 estimate of short-term dietary and residential exposure 
resulted in an MOE of 6,800, which is well above the minimum acceptable 
MOE of 100. Further, the short-term DWLOC is over 2,800 fold greater 
than the short-term EEC for surface water and ground water. Thus, based 
on the completeness and reliability of the toxicity data and the 
conservative exposure assessment, Dow AgroSciences concludes that there 
is a reasonable certainty that no harm will result to the general U.S. 
population from aggregate acute, short-term or chronic exposure to 
clopyralid residues from current and proposed uses.
    2. Infants and children. In assessing the potential for additional 
sensitivity of infants and children to residues of clopyralid, data are 
considered from developmental toxicity studies in the rat and rabbit, 
and from multiple generation reproduction studies in rats. The 
developmental toxicity studies are designed to evaluate adverse effects 
on the developing organism resulting from maternal pesticide exposure 
during gestation. Reproductive studies provide information relating to 
prenatal and postnatal effects from exposure to the pesticide, on the 
reproductive capability of mating animals, and data on systemic 
toxicity.
    Based on the results of developmental toxicity and 
multigenerational reproduction studies, there are no indications of 
prenatal or postnatal toxicity concerns for infants and children from 
exposure to clopyralid. 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 for clopyralid relative to prenatal and 
postnatal effects for children is complete. There were no indications 
of neurotoxicity and developmental toxicity was not observed in the 
absence of maternal toxicity. It is concluded that there is no 
indication of increased sensitivity of infants and children relative to 
adults and that an additional FQPA safety factor is not required.
    Using conservative exposure assumptions previously described, acute 
dietary exposure to residues of clopyralid from current and proposed 
uses was estimated to occupy only 6.91% of the RfD for children 1-6 
years old, the population subgroup estimated to be most highly exposed. 
EPA generally has no concern for exposures below 100% of the RfD since 
the RfD represents the level at or below which exposure will not pose 
appreciable risks to human health. Additionally, the acute DWLOC was 
calculated to be over 900 fold greater than potential clopyralid 
residue in drinking water as predicted by conservative screening-level 
models. A conservative Tier 1 assessment indicated that chronic dietary 
exposure for children 1-6 years old would occupy only 5.4% of the 
chronic RfD. Additionally, the chronic DWLOC was calculated to be over 
500 fold greater than surface water or ground water EECs developed by 
screening-level models. A Tier 1 estimate of short-term dietary and 
residential exposure for children 1-6 years old resulted in an MOE of 
2,300, which is well above the minimum acceptable MOE of 100. Further, 
the short-term DWLOC is over 700 fold greater than the short-term EEC 
for surface water and ground water. Thus, based on the completeness and 
reliability of the toxicity data and the conservative exposure 
assessment, Dow AgroSciences concludes that there is a reasonable 
certainty that no harm will result to infants and children from 
aggregate acute, short-term or chronic exposure to clopyralid residues 
from current and proposed uses.

F. International Tolerances

    There are no Codex or Mexican maximum residue limits. Canada has 
set a maximum residue limit of 2.0 ppm for barley, oats, and wheat, and 
7.0 ppm for the milled fractions of barley, oats, and wheat (excluding 
flour).
[FR Doc. 02-20230 Filed 8-13-02; 8:45 am]
BILLING CODE 6560-50-S