Imidacloprid - Pesticide Petition Filing 1/00
[Federal Register: February 11, 2000 (Volume 65, Number 29)]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
ENVIRONMENTAL PROTECTION AGENCY
Notice of Filing a Pesticide Petition to Establish a Tolerance
for Certain Pesticide Chemicals in or on Food
AGENCY: Environmental Protection Agency (EPA).
SUMMARY: This notice announces the initial filing of a pesticide
petition proposing the establishment of regulations for residues of
certain pesticide chemicals in or on various food commodities.
DATES: Comments, identified by docket control number PF-915, must be
received on or before March 13, 2000.
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-915 in the subject line on the first page of your
FOR FURTHER INFORMATION CONTACT: By mail: Peg Perreault, Registration
Support Branch, Registration Division (7505C), Office of Pesticide
Programs, Environmental Protection Agency, Ariel Rios Bldg., 1200
Pennsylvania Ave., NW., Washington, DC 20460; telephone number: (703)
305-5417; e-mail address: email@example.com.
I. General Information
A. Does this Action Apply to Me?
You may be affected by this action if you are an agricultural
producer, food manufacturer or pesticide manufacturer. Potentially
affected categories and entities may include, but are not limited to:
Categories NAICS codes potentially
Industry 111 Crop production
112 Animal production
311 Food manufacturing
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in the table could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether or not this action might apply to certain entities. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed under "FOR FURTHER INFORMATION
B. How Can I Get Additional Information, Including Copies of this
Document and Other Related Documents?
1. Electronically. You may obtain electronic copies of this
document, and certain other related documents that
might be available 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/
2. In person. The Agency has established an official record for
this action under docket control number PF-915. 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 Mall2, 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-915 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, Ariel Rios Bldg., 1200 Pennsylvania Ave., NW., Washington, DC
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 Mall2, 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: "firstname.lastname@example.org," 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-915. 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
E. What Should I Consider as I Prepare My Comments for EPA?
You may find the following suggestions helpful for preparing your
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide copies of any technical information and/or data you used
that support your views.
4. If you estimate potential burden or costs, explain how you
arrived at the estimate that you provide.
5. Provide specific examples to illustrate your concerns.
6. Make sure to submit your comments by the deadline in this
7. To ensure proper receipt by EPA, be sure to identify the docket
control number assigned to this action in the subject line on the first
page of your response. You may also provide the name, date, and Federal
II. What Action is the Agency Taking?
EPA has received a pesticide petition as follows proposing the
establishment and/or amendment of regulations for residues of a certain
pesticide chemical in or on various food commodities under section 408
of the Federal Food, Drug, and 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.
List of Subjects
Environmental protection, Agricultural commodities, Feed additives,
Food additives, Pesticides and pests, Reporting and recordkeeping
Dated: January 27, 2000.
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.
EPA has received a pesticide petition (PP 8F4940) from BAYER
Corporation, 8400 Hawthorn Road, P.O. Box 4913, Kansas City, MO 64120-
0013 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
by establishing a tolerance for residues of imidacloprid in or on the
raw agricultural commodities (RAC): citrus fruit, citrus pulp, dried
and the leafy petiole subgroup (4-B) at 0.7, 5.0, and 6.0 parts per
million (ppm), respectively. 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 imidacloprid residue in
plants is adequately understood. The residues of concern are combined
residues of imidacloprid and it metabolites containing the 6-
chloropyridinyl moiety, all calculated as imidacloprid.
2. Analytical method. The analytical method is a common moiety
method for imidacloprid and its metabolites containing the 6-
chloropyridinyl moiety using a permanganate oxidation, silyl
derivatization, and capillary gas chromatography mass spectrometry (GC/
MS) selective ion monitoring. This method has successfully passed a
petition method validation in EPA labs. There is a confirmatory method
specifically for imidacloprid and several metabolites utilizing GC/MS
and high performance liquid chromotography using ultra-violet detection
(HPLC-UV) which has been validated by EPA as well. Imidacloprid and its
metabolites are stable for at least 24 months in the commodities when
3. Magnitude of residues--i. Citrus. Forty-three residue crop field
trials (23 foliar applications and 20 soil applications) were conducted
to evaluate the quantity of imidacloprid expected in citrus from Admire
2, Flowable and Provado 1.6 applications. These trials were conducted
in EPA Regions III, VI, and X. Imidacloprid residues in citrus whole
fruit (oranges, grapefruit, and lemons) were quantitated by GC using a
MS detector. The limit of quantitation (LOQ) was 0.05 ppm. The highest
average field trial (HAFT) was 0.61 ppm in oranges. A processing study
at 5 times the maximum recommended label use rate was conducted to
evaluate the quantity of imidacloprid and metabolite residue in orange
processed commodities following treatment of orange trees with Admire
2F. Harvested whole oranges were processed into dried pulp, oil,
molasses, and juice using procedures which simulated commercial orange
processing practices. Imidacloprid and metabolite residues in orange
whole fruit and orange processed commodities were quantitated by GC
using a MS detector. Total residue of imidacloprid and metabolites in
orange whole fruit was 0.19 ppm. EPA's Table 1 - RAC and processed
commodities and feedstuffs derived from crops lists dried pulp, oil,
and juice as processed commodities. The processing study showed a total
residue for imidacloprid and metabolites of 1.42 ppm (7.5x
concentration) in dried pulp and no concentration of total residue of
imidacloprid and metabolites in both orange juice and oil (0.05 ppm).
ii. Leaf petioles subgroup vegetables. Twelve residue crop field
trials on celery were conducted to evaluate the quantity of
imidacloprid expected in members of the leaf petiole vegetable subgroup
from Admire 2 Flowable applications. These trials, which compared plant
drench, soil sidedress and in-furrow at transplant applications, were
conducted in EPA Regions III, V, VI, X, and XI. Imidacloprid residues
in untrimmed celery stalks were quantitated by using a GC/MC. The LOQ
was 0.05 ppm. Total residue values ranged from 0.13 to 5.62 ppm.
B. Toxicological Profile
1. Acute toxicity. The acute oral LD50 values for
imidacloprid technical ranged from 424 - 475 milligrams/kilograms/body
weight (mg/kg/bwt) in the rat. The acute dermal LD50 was
greater than 5,000 mg/kg in rats. The 4-hour rat inhalation
LC50 was 69 mg/m**3 air (aerosol). Imidacloprid was
not irritating to rabbit skin or eyes. Imidacloprid did not cause skin
sensitization in guinea pigs.
2. Genotoxicity. Extensive mutagenicity studies conducted to
investigate point and gene mutations, DNA damage and chromosomal
aberration, both using in vitro and in vivo test systems show
imidacloprid to be non-genotoxic.
3. Reproductive and developmental toxicity. A 2-generation rat
reproduction study gave a no-observed adverse effect level (NOAEL) of
100 ppm (8 mg/kg/bwt). Rat and rabbit developmental toxicity studies
were negative at doses up to 30 mg/kg/bwt and 24 mg/kg/bwt,
4. Subchronic toxicity. Ninety-day feeding studies were conducted
in rats and dogs. The NOAELs for these tests were 14 mg/kg bwt/day (150
ppm) and 5 mg/kg bwt/day (200 ppm) for the rat and dog studies,
5. Chronic toxicity. A 2-year rat feeding/carcinogenicity study was
negative for carcinogenic effects under the conditions of the study and
had a NOAEL of 100 ppm (5.7 mg/kg/bwt in male and 7.6 mg/kg/bwt female)
for noncarcinogenic effects that included decreased bwt gain in females
at 300 ppm and increased thyroid lesions in males at 300 ppm and
females at 900 ppm. A 1-year dog feeding study indicated a NOAEL of
1,250 ppm (41 mg/kg/bwt). A 2-year mouse carcinogenicity study that was
negative for carcinogenic effects under conditions of the study and had
a NOAEL of 1,000 ppm (208 mg/kg/day). Imidacloprid has been classified
under "Group E" (no evidence of carcinogenicity) by EPA's OPP/HED's
Reference Dose (RfD) Committee. There is no cancer risk associated with
exposure to this chemical. The RfD based on the 2-year rat feeding/
carcinogenic study with a NOAEL of 5.7 mg/kg/bwt and 100-fold
uncertainty factor, is calculated to be 0.057 mg/kg/bwt.
6. Animal metabolism. The metabolism of imidacloprid in rats was
reported in seven studies. Data in these studies show that imidacloprid
was rapidly absorbed and eliminated in the excreta (90% of the dose
within 24 hours), demonstrating no biologically significant differences
between sexes, dose levels, or route of administration. Elimination was
mainly renal (70-80% of the dose) and fecal (17-25%). The major part of
the fecal activity originated in the bile. Total body accumulation
after 48 hours consisted of 0.5% of the radioactivity with the liver,
kidney, lung, skin and plasma being the major sites of accumulation.
Therefore, bioaccumulation of imidacloprid is low in rats. Maximum
plasma concentration was reached between 1.1 and 2.5 hours. Two major
routes of biotransformation were proposed for imidacloprid. The first
route included an oxidative cleavage of the parent compound rendering
6-chloronicotinic acid and its glycine conjugate. Dechlorination of
this metabolite formed the 6-hydroxynicotinic acid and its mercapturic
acid derivative. The second route included the hydroxylation followed
by elimination of water from the parent compound.
7. Metabolite toxicology. Several metabolites of imidacloprid have
been investigated for acute toxicity and genotoxicity. No evidence for
genotoxicity was found, and acute toxicity values for all metabolites
studied ranged from slightly more toxic to significantly less toxic
than parent imidacloprid.
8. Endocrine disruption. The toxicology data base for imidacloprid
is current and complete. Studies in this data base include evaluation
of the potential effects on reproduction and development, and an
evaluation of the pathology of the endocrine organs following short-
term or long-term exposure. These studies revealed no primary endocrine
effects due to imidacloprid.
C. Aggregate Exposure
1. Dietary exposure--i. Food. For purposes of assessing the
potential acute and chronic dietary exposure, Bayer has estimated
exposure based on the theoretical maximum residue contribution (TMRC).
The TMRC is obtained by using a model which multiplies the tolerance
level residue for each commodity by consumption data. The consumption
data, based on the NFCS 1989-92 data base, estimates the amount of each
commodity and products derived from the commodities that are eaten by
the U.S. population and various population subgroups.
a. Acute. For acute dietary exposure the model calculates a margin
of exposure (MOE) by dividing the estimated human exposure into the
NOAEL from the appropriate animal study. Commonly, EPA finds MOEs lower
than 100 to be unacceptable. EPA has determined that a NOAEL of 24 mg/
kg/day from a developmental toxicity study in rabbits should be used to
assess acute toxicity.
The MOE for imidacloprid derived from previously established
tolerances, pending tolerances, plus the proposed use on citrus and the
leaf petiole subgroup would be 366 for the U.S. population (48
contiguous States), 323 for non-nursing infants, 101 for children (ages
1-6 years), 420 for children (ages 7-12 years), 622 for males 13+
years, and 554 for females 13+ years at the 99.9 percentile. These MOEs
do not exceed EPA's level of concern for acute dietary exposure.
b. Chronic. For purposes of assessing the potential chronic dietary
exposure, the model uses the RfD which EPA has determined to be 0.057
mg/kg/day. This is based on the 2-year rat feeding/carcinogenic study
with a NOAEL of 5.7 mg/kg/bwt and 100-fold uncertainty factor. In
conducting this exposure assessment, very conservative assumptions
(100% of all commodities contain imidacloprid residues and those
residues are at the level of the tolerance) result in a large
overestimate of human exposure.
Using these conservative assumptions, the TMRC for imidacloprid
derived from previously established tolerances, pending tolerances,
plus the proposed use on citrus and leaf petiole subgroup would be
0.008149 mg/kg bwt/day (14.3% of the RfD) for the U.S. population (48
contiguous States) and 0.018367 mg/kg bwt/day (32.2% of the RfD) for
the most highly exposed population subgroup, children (1-6 years old).
Therefore, chronic dietary exposure from the existing and proposed uses
will not exceed the RfD for any subpopulation, including infants and
ii. Drinking water. EPA has determined that imidacloprid is
persistent and could potentially leach into groundwater. However, there
is no established maximum contamination level (MCL) or health advisory
levels established for imidacloprid in drinking water. EPA's
"Pesticides in Groundwater Database" has no entry for imidacloprid.
In addition, Bayer is not aware of imidacloprid being detected in any
ponds, lakes, streams, etc. from its use in the United States.
Groundwater monitoring studies conducted in California, Michigan, and
Long Island over the past 2 years have found maximum concentrations to
be only 0.0001, 0.0002, and 0.0019 milligrams/liter (mg/L),
respectively. Therefore, contributions to the dietary burden from
residues of imidacloprid in water would be inconsequential.
2. Non-dietary exposure--i. Residential turf. Bayer has conducted
an exposure study to address the potential exposures of adults and
children from contact with imidacloprid treated turf. The population
considered to have the greatest potential exposure from contact with
pesticide treated turf soon after pesticides are applied are young
children. Margins of safety (MOS) of 7,587 - 41,546 for 10-year old
children and 6,859 - 45,249 for 5-year old children were estimated by
comparing dermal exposure doses to the imidacloprid NOAEL of 1,000 mg/
kg/day established in a 15-day dermal toxicity study in rabbits. The
estimated safe residue levels of imidacloprid on treated turf for 10-
year old children ranged from 5.6 - 38.2 g/cm**2 and for 5-
year old children from 5.1 - 33.5 g/cm**2. This compares with
the average imidacloprid transferable residue level of 0.080 g/
cm**2 present immediately after the sprays have dried. These
data indicate that children can safely contact imidacloprid-treated
turf as soon after application as the spray has dried.
ii. Termiticide. Imidacloprid is registered as a termiticide. Due
to the nature of the treatment for termites, exposure would be limited
to that from inhalation and was evaluated by EPA's Occupational and
Residential Exposure Branch (OREB) and Bayer. Data indicate that the
MOS for the worst case exposures for adults and infants occupying a
treated building who are exposed continuously (24 hours/day) are 8.0 x
107 and 2.4 x 108, respectively; exposure can thus be considered
iii. Tobacco smoke. Studies have been conducted to determine
residues in tobacco and the resulting smoke following treatment.
Residues of imidacloprid in cured tobacco following treatment were a
maximum of 31 ppm (7 ppm in fresh leaves). When this tobacco was burned
in a pyrolysis study, only 2% of the initial residue was recovered in
the resulting smoke (main stream plus side stream). This would result
in an inhalation exposure to imidacloprid from smoking of approximately
0.0005 mg per cigarette. Using the measured subacute rat inhalation
NOAEL of 5.5 mg/m**3, it is apparent that exposure to
imidacloprid from smoking (direct and/or indirect exposure) would not
iv. Pet treatment. Human exposure from the use of imidacloprid to
treat dogs and cats for fleas has been addressed by EPA's OREB who have
concluded that due to the fact that imidacloprid is not an inhalation
or dermal toxicant and that while dermal absorption data are not
available, imidacloprid is not considered to present a hazard via the
D. Cumulative Effects
No other chemicals having the same mechanism of toxicity are
currently registered, therefore, there is no risk from cumulative
effects from other substances with a common mechanism of toxicity.
E. Safety Determination
1. U.S. population. Using the conservative exposure assumptions
described under aggregate exposure and based on the completeness and
reliability of the toxicity data, it can be concluded that total
aggregate exposure to imidacloprid from all current uses including
those currently proposed will utilize little more than 14.3% of the RfD
for the U.S. population from food, water, and non-occupational sources.
EPA generally has no concern for exposures below 100% of the RfD,
because the RfD represents the level at or below which daily aggregate
exposure over a lifetime will not pose appreciable risks to human
health. In addition, the MOEs for all population groups does not exceed
EPA's level of concern for acute dietary exposure. Thus, it can be
concluded that there is a reasonable certainty that no harm will result
from aggregate exposure to imidacloprid residues.
2. Infants and children. In assessing the potential for additional
sensitivity of infants and children to residues of imidacloprid, the
data from developmental studies in both rat and rabbit and a 2-
generation reproduction study in the rat have been considered. The
developmental toxicity studies evaluate potential adverse effects on
developing animal resulting from pesticide exposure of the mother
during prenatal development. The reproduction study evaluates effects
from exposure to the pesticide on the reproductive capability of mating
animals through two generations, as well as any observed systemic
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 effects and the completeness of the
toxicity data base. Based on current toxicological data requirements,
the toxicology database for imidacloprid relative to prenatal and
postnatal effects is complete. Further for imidacloprid, the NOAEL of
5.7 mg/kg/bwt from the 2-year old rat feeding/ carcinogenic study,
which was used to calculate the RfD (discussed above), is already lower
than the NOAELs from the developmental studies in rats and rabbits by a
factor of 4.2 to 17.5 times. Since a 100-fold uncertainty factor is
already used to calculate the RfD, it is surmised that an additional
uncertainty factor is not warranted and that the RfD at 0.057 mg/kg
bwt/day is appropriate for assessing aggregate risk to infants and
Using the conservative exposure assumptions described above under
aggregate exposure, Bayer has determined from a chronic dietary
analysis that the percent of the RfD utilized by aggregate exposure to
residues of imidacloprid ranges from 9.3% for nursing infants up to
32.2% for children (1-6 years old). EPA generally has no concern for
exposure below 100% of the RfD. In addition, the MOEs for all infant
and children population groups do not exceed EPA's level of concern for
acute dietary exposure. Therefore, based on the completeness and
reliability of the toxicity data and the conservative exposure
assessment, there is a reasonable certainty that no harm will result to
infants and children from aggregate exposure to the residues of
imidacloprid, including all anticipated dietary exposure and all other
F. International Tolerances
No CODEX maximum residue levels have been established for residues
of Imidacloprid on any crops at this time.
[FR Doc. 00-3220 Filed 2-10-00; 8:45 am]
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