[Federal Register Volume 65, Number 129 (Wednesday, July 5, 2000)]
[Notices]
[Pages 41455-41460]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-16765]


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ENVIRONMENTAL PROTECTION AGENCY

[PF-948; FRL-6590-6]


Notice of Filing of 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 
certain pesticide chemicals in or on various food commodities.

DATES: Comments, identified by docket control number PF-948, must be 
received on or before August 4, 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-948 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) 308-3194; e-mail address: 
<a href="/cdn-cgi/l/email-protection#ef8d9d809b878a9d9cc19c878e858eaf8a9f8ec1888099"><span class="__cf_email__" data-cfemail="5230203d263a3720217c213a333833123722337c353d24">[email protected]</span></a>.

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'' 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-948. 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-948 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.

[[Page 41456]]

    3. Electronically. You may submit your comments electronically by 
e-mail to: ``<a href="/cdn-cgi/l/email-protection#eb849b9bc68f8488808e9fab8e9b8ac58c849d"><span class="__cf_email__" data-cfemail="89e6f9f9a4ede6eae2ecfdc9ecf9e8a7eee6ff">[email protected]</span></a>,'' 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-948. 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 
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 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 Comestic Act (FFDCA), 21 U.S.C. 346a. 
EPA has determined that these 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.

    Dated: June 26, 2000.
James Jones,
Director, Registration Division, Office of Pesticide Programs.

Summaries 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 petitioner and represents the view 
of the petitioner. The petition summaries announce 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)

9E6041, 0E6101, 0E6102, 0E6104, 0E6106, and 0E6156

    EPA has received pesticide petitions 9E6041, 0E6101, 0E6102, 
0E6104, 0E6106, and 0E6156 from the Interregional Research Project No. 
4, 681 U.S. Highway #1 South, North Brunswick, NJ 08902-3390 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 
tolerances for residues of the insecticide imidacloprid, 1-(6-chloro-3-
pyridinyl)methyl-N-nitro-2-imidazolidinimine in or on the following raw 
agricultural commodities:
    1. PP 9E6041 proposes the establishment of a tolerance for cilantro 
at 3.5 parts per million (ppm).
    2. PP 0E6101 proposes the establishment of a tolerance for edible 
podded bean at 1.0 ppm.
    3. PP 0E6102 proposes the establishment of a tolerance for hops at 
4.0 ppm.
    4. PP 0E6104 proposes the establishment of a tolerance for 
succulent shelled bean at 1.0 ppm.
    5. PP 0E6106 proposes the establishment of a tolerance for sweet 
corn at 0.05 ppm, sweet corn forage at 0.1 ppm, and sweet corn stover 
at 0.2 ppm.
    6. PP 0E6156 proposes the establishment of a tolerance for turnip 
tops (leaves) at 3.5 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 petitions prepared by 
Zeneca Ag Products, Wilmington, DE 19850-5458.

A. Residue Chemistry

    1. Plant metabolism. The nature of the imidacloprid residue in 
plants and livestock 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 chromatography 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 
frozen.
    3. Magnitude of residues-- i. Turnip tops. IR-4 has received 
requests from the California, Oregon, Texas, Mississippi, Oklahoma, 
Florida, Ohio, and Tennessee agricultural experiment stations for the 
registration of imidacloprid on turnip tops (leaves). No

[[Page 41457]]

data are presented in support of this petition; rather, IR-4 requests 
that the registrant's Brassica vegetable data be used to support this 
request for turnip tops. Turnips are very closely related to the 
Brassica vegetables. This request does not include a tolerance for 
turnip roots.
    ii. Succulent shelled beans. Seven field trials were conducted in 
order to provide information on the magnitude of imidacloprid residues 
on lima beans following planting application plus three foliar 
applications of imidacloprid. Trials were conducted in Maryland, South 
Carolina, Georgia, Ohio, California and Washington. Residue levels 
ranged from <0.05 ppm to 0.67 ppm. A tolerance of 1.0 ppm is being 
proposed by IR-4.
    iii. Edible podded beans. Six field trials were conducted in order 
to provide information on the magnitude of imidacloprid residues on 
snap beans following the planting application plus 3 foliar 
applications of imidacloprid. Trials were conducted in South Carolina, 
Florida, Wisconsin, Ohio, New York, and Washington. Residue levels 
ranged from <0.05 ppm to 0.89 ppm. A tolerance of 1.0 ppm is being 
proposed by IR-4.
    iv. Sweet corn. IR-4 received a request from New York for 
registration of imidacloprid seed treatment on sweet corn. Imidacloprid 
is currently registered for use on field corn. Tolerances for kernel + 
cob with husk removed (K + CWHR), sweet corn forage and sweet corn 
stover were requested based on field corn data and validation of method 
on K + CWHR samples.
    v. Cilantro. The nature of imidacloprid residues is adequately 
understood and an analytical method is available for enforcement 
purposes. IR-4 requests that EPA grant an imidacloprid tolerance for 
cilantro based on the similarity of cilantro to other leafy non-
Brassica vegetables (especially fresh parsley) for which imidacloprid 
is already registered. Based on the available information, and the 
currently registered use patterns for leafy non-Brassica vegetables on 
the Admire<Register> and Provado<Register> labels, the establishment of 
a tolerance for cilantro (fresh leaves and stems) would protect the 
public health, and would not expose man or the environment to 
unreasonable adverse effects.
    vi. Hops. Based on available data, the proposed use, foliar 
treatment of pirimicarb insecticide at the rate of 1 lb (0.5 lb active) 
per acre up to a maximum of 1 lb active ingredient/acre (ai/acre) per 
year, minimum 7-day pre-harvest interval, should be supported. Based on 
the available information, the establishment of the tolerance proposed 
in the petition would protect the public health, and would not expose 
man or the environment to unreasonable adverse effects, while providing 
growers with a safe and effective insectide.

B. Toxicological Profile

    1. Acute toxicity. The acute oral lethal dose (LD)<INF>50</INF> 
values for imidacloprid-technical ranged from 424 milligrams/kilograms 
(mg/kg) in the male rat and >450 mg/kg in the female rat. The acute 
dermal LD<INF>50</INF> was >5,000 mg/kg in the rat. The 4-hour rat 
inhalation lethal concentration (LC)<INF>50</INF> was >5.33 milligram/
Liter (mg/L). Imidacloprid was not irritating to rabbit skin or eyes. 
Imidacloprid did not cause skin sensitization in guinea pigs. In an 
acute neurotoxicity study, the lowest observed adverse effect level 
(LOAEL) = 42 mg/kg body weight (bwt)/day.
    2. Genotoxicity. Mutagenicity studies have demonstrated that 
imidacloprid is non-mutagenic both in vivo and in vitro.
    3. Reproductive and developmental toxicity. In a developmental 
toxicity study with Sprague-Dawley rats, groups of pregnant animals 
(25/group) received oral administration of imidacloprid (94.2%) at 0, 
10, 30, or 100 mg/kg bwt/day during gestation days 6 through 16. 
Maternal toxicity was manifested as decreased body weight gain at all 
dose levels and reduced food consumption at 100 mg/kg bwt/day. No 
treatment-related effects were seen in any of the reproductive 
parameters (i.e., Cesarean section evaluation). At 100 mg/kg bwt/day, 
developmental toxicity manifested as wavy ribs (fetus =7/149 in treated 
vs. 2/158 in controls and litters, 4/25 vs. 1/25). For maternal 
toxicity, the LOAEL was 10 mg/kg bwt/day lowest dose tested (LDT) based 
on decreased body weight gain; a no observed adverse effect level 
(NOAEL) was not established. For developmental toxicity, the NOAEL was 
30 mg/kg bwt/day, and the LOAEL was 100 mg/kg bwt/day based on 
increased wavy ribs.
    In a developmental toxicity study with Chinchilla rabbits, groups 
of 16 pregnant does were given oral doses of imidacloprid (94.2%) at 0, 
8, 24, or 72 mg/kg bwt/day during gestation days 6 through 18. For 
maternal toxicity, the NOAEL was 24 mg/kg bwt/day and the LOAEL was 72 
mg/kg bwt/day based on mortality, decreased body weight gain, increased 
resorptions, and increased abortions. For developmental toxicity, the 
NOAEL was 24 mg/kg bwt/day and the LOAEL was 72 mg/kg bwt/day based on 
decreased fetal body weight, increased resorptions, and increased 
skeletal abnormalities.
    In a 2-generation reproductive toxicity study, imidacloprid (95.3%) 
was administered to Wistar/Han rats at dietary levels of 0, 100, 250, 
or 700 ppm (0, 7.3, 18.3, or 52.0 mg/kg bwt/day for males and 0, 8.0, 
20.5, or 57.4 mg/kg bwt/day for females). For parental/systemic/
reproductive toxicity, the NOAEL was 250 ppm (18.3 mg/kg bwt/day) and 
the LOAEL was 750 ppm (52 mg/kg bwt/day), based on decreases in body 
weight in both sexes in both generations. Based on these factors, the 
parental/systemic/reproductive NOAEL and LOAEL are 250 and 700 ppm, 
respectively, based upon the body weight decrements observed in both 
sexes in both generations.
    4. Subchronic toxicity. In a dermal toxicity study, groups of 5 
male and 5 female New Zealand white rabbits received repeated dermal 
applications of imidacloprid (95%) at 1,000 mg/kg bwt/day (limit dose), 
6-hours/day, 5-days/week for 3-weeks. No dermal or systemic toxicity 
was seen. For systemic and dermal toxicity, the NOAEL was >1,000 mg/kg 
bwt/day; a LOAEL was not established.
    In an oral toxicity study, groups of Fischer 344 rats (12/sex/dose) 
were fed diets containing imidacloprid (98.8%) at 0, 150, 1,000, or 
3,000 ppm (0, 9.3, 63.3, or 196 mg/kg bwt/day in males and 0, 10.5, 
69.3, or 213 mg/kg bwt/day in females, respectively) for 90-days. No 
treatment-related effects were seen at 150 ppm. Treatment-related 
effects included decreases in body weight gain during the first 4 weeks 
of the study at 1,000 ppm (22% in males and 18% in females) and 3,000 
ppm (50% in males and 25% in females) with an associated decrease in 
forelimb grip strength especially in males. The NOAEL was 150 ppm (9.3 
and 10.5 mg/kg bwt/day in males and females, respectively) and the 
LOAEL was 1,000 ppm (63.3 and 69.3 mg/kg bwt/day in males and females, 
respectively).
    In a rat inhalation study (28-day study in which rats were exposed 
6 hours/day, 5 days/week for 4 weeks), the NOAEL for imidacloprid was 
5.5 mg/m<SUP>3</SUP>.
    5. Chronic toxicity. In a chronic toxicity study, groups of Beagle 
dogs (4/sex/dose) were fed diets containing imidacloprid (94.9%) at 0, 
200, or 1,250/2,500 ppm (0, 6.1, 15, or 41/72 mg/kg bwt/day, 
respectively) for 52 weeks. The 1,250 ppm dose was increased to 2,500 
ppm from week 17 onwards. The threshold NOAEL was 1,250 ppm (41 mg/kg 
bwt/day). The LOAEL was 2,500 ppm (72 mg/kg bwt/day) based on increased 
cytochrome-P-450 levels in both sexes and was considered to be a 
threshold dose. Due

[[Page 41458]]

to the lack of toxicity at 1,250 ppm, a LOAEL was not established in 
this study; following the dose increase to the 2,500 ppm level, 
toxicity was observed, thus making 1,250 ppm the threshold NOAEL and 
2,500 ppm the threshold LOAEL.
    6. Animal metabolism. The metabolism of NTN 33893 (imidacloprid) in 
rats was reported in seven studies. Data showed 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 of the parent compound rendering NTN 35884. A 
comparison between [methylene-<SUP>-14</SUP>C]-imidacloprid and 
[imidazolidine-4,5<SUP>-14</SUP>C]-imidacloprid showed that while the 
rate of excretion was similar, the renal portion was higher with the 
imidazolidine-labeled compound. In addition, accumulation in tissues 
was generally higher with the imidazolidine-labeled compound. Also, a 
comparison between imidacloprid and one of its metabolites, WAK 3839, 
showed that the total elimination was the same for both compounds. The 
proposed metabolic pathways for these two compounds were different. WAK 
3839 was formed following pretreatment (repeated dosing) of 
imidacloprid.
    7. 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. Assessments were conducted to evaluate 
potential risks due to chronic and acute dietary exposure of the U.S. 
population and selected population subgroups to residues of 
imidacloprid. These analyses cover all registered crops including 
rotational crops; uses pending with the EPA on citrus, leafy petiole 
crop group, corn, and sweet corn; active and proposed Section 18 uses 
on blueberries, cranberries, table beets, strawberries, turnips; new 
proposed IR-4 uses on succulent beans, blueberries, turnips and 
cilantro; and an import tolerance petition on bananas.
    Novigen Sciences, Inc.'s dietary exposure evaluation model 
(DEEM<SUP>TM</SUP>), which is licensed to Bayer, was used to estimate 
the chronic and acute dietary exposure. Version 6.76 was used for the 
chronic analysis and version 6.79 for the acute analysis. This software 
uses the food consumption data from the 1994-1996 U.S. Department of 
Argiculture (USDA) continuing surveys of food intake by individuals 
CSFII 1994-1996.
    The endpoint for acute dietary risk assessments is based on 
neurotoxicity characterized by decreases in motor or locomotor activity 
in female rats at 42 mg/kg bwt/day (LOAEL) from an acute neurotoxicity 
study. Based on an uncertainty factor (UF) of 10X for interspecies and 
10X for intraspecies the acute reference dose (RfD) = 0.42 mg/kg bwt/
day. EPA has determined that an additional UF for FQPA (reduced to 3X) 
applies to all population subgroups for acute risk. Application of the 
additional 3X safety factor results in an acute population adjusted 
dose (aPAD) 0.14 mg/kg bwt/day or a margin of exposure (MOE) of 300.
    For chronic dietary analyses, EPA has established the RfD for 
imidacloprid at 0.057 mg/kg/day based on a NOAEL of 5.7 mg/kg bwt/day 
from a rat chronic toxicity carcinogenicity study and UFs of 10X for 
interspecies and 10X for intraspecies. EPA has determined that an UF 
for FQPA (reduced to 3X) applies to all population subgroups for 
chronic risk. Application of the additional 3X safety factor results in 
a chronic population adjusted dose (cPAD) of 0.019 mg/kg bwt/day.
    Results from the acute and chronic dietary exposure analyses 
described below demonstrate a reasonable certainty that no harm to the 
overall U.S. population or any population subgroup will result from the 
use of imidacloprid on currently registered and pending uses.
    i. Food. Acute and chronic (tier 3) risk assessments were made 
using the results of field trials conducted at maximum label 
application rates and the shortest post harvest interval (PHI). For 
some of the vegetable crops, these residue data were collected at 1.5X 
or greater than the maximum label rate of 0.5 lb ai/acre per season. In 
addition, no adjustments were made to account for dissipation of 
residues during storage, transportation from the field to the consumer, 
washing or peeling. Therefore, the actual dietary exposure will be less 
than that presented here.
    For the chronic analysis, mean field trial residues were 
calculated. For the acute Monte Carlo analysis, the entire distribution 
of residue field trial data was used for the ``non-blended'' and 
``partially-blended'' foods as determined by EPA. For the foods 
considered as ``blended'' by EPA, mean field trial residue data were 
used. As allowed in EPA's draft guidance for submission of 
probabilistic human health exposure assessments one half limit of 
detection/limit of quantitation (LOD/LOQ) values were used for all non-
detected values (values below the sensitivity of the method).
    ii. Acute. Bayer's acute Monte Carlo dietary exposure assessment 
estimated percent of the aPAD and corresponding margins of exposure 
(MOE) for the overall U.S. population (all seasons) and various 
subpopulations. In this analysis, the exposure for the total U.S. 
population was equal to 6.82% of the aPAD at the 99.9th percentile. The 
most highly exposed population subgroup, children (1-6 yrs), had an 
exposure equal to 13.44% of the aPAD at the 99.9th percentile. 
Therefore, the acute dietary exposure estimates are below EPA's level 
of concern for the overall U.S. population as well as the various 
subpopulations.
    iii. Chronic. Bayer's chronic dietary exposure estimated the 
percent of the cPAD for the overall U.S. population (all seasons) and 
various subpopulations. In this analysis, the exposure for the total 
U.S. population was equal to 1.4% of the cPAD. The most highly exposed 
population subgroup, children (1-6 yrs), had an exposure equal to 2.7% 
of the cPAD. Therefore, the chronic exposure estimates are below EPA's 
level of concern for the overall U.S. population as well as the various 
subpopulations.
    iv. Drinking water. EPA has determined that imidacloprid is 
persistent and could potentially leach into ground water. However, 
there is no established maximum concentration level (MCL) or health 
advisory levels established for imidacloprid in drinking water. EPA's 
``pesticides in ground water data base'' has no entry for imidacloprid. 
In addition, Bayer is not

[[Page 41459]]

aware of imidacloprid being detected in any wells, ponds, lakes, 
streams, etc. from its use in the U.S. In studies conducted in 1995, 
imidacloprid was not detected in 17 wells on potato farms in Quebec, 
Canada. 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 application are young 
children. Margins of safety 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<SUP>2</SUP> and for 5-year-old 
children from 5.1 - 33.5 g/cm<SUP>2</SUP>. This compares with the 
average imidacloprid transferable residue level of 0.080 g/
cm<SUP>2</SUP> present immediately after the sprays have dried. 
According to Bayer, 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's (OREB) and Bayer. Data indicate that the 
margins of safety for the worst case exposures for adults and infants 
occupying a treated building who are exposed continuously (24 hours/
day) are 8.0 x 10<SUP>7</SUP> and 2.4 x 10<SUP>8</SUP>, respectively. 
According to Bayer, exposure can be considered negligible.
    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<SUP>3</SUP>, it is apparent that exposure to 
imidacloprid from smoking (direct and/or indirect exposure) would not 
be significant.
    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 
dermal route.

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. Based on the exposure assessments described 
above and on the completeness and reliability of the toxicity data, it 
can be concluded that the exposure estimates from all label and pending 
uses of imidacloprid are 6.82% of the aPAD and 1.4% of the cPAD for 
dietary exposures. EPA generally has no concerns for exposures below 
100% of the PAD. Thus, Bayers concludes that there is a reasonable 
certainty that no harm will result from aggregate exposure to 
imidacloprid residues.
    2. Infants and children. In the Federal Register (63 FR 49837, 
September 18, 1998) (FRL-6027-1). EPA has assessed the potential for 
additional sensitivity of infants and children to residues of 
imidacloprid. EPA has considered data from developmental toxicity 
studies in the rat and rabbit and a 2-generation reproduction study in 
the rat. These studies are discussed under section A (toxicology 
profile) above. The developmental toxicity data demonstrated no 
increased sensitivity of rats or rabbits to in utero exposure to 
imidacloprid. In addition, the multi-generation reproductive toxicity 
study did not identify any increased sensitivity of rats to in utero or 
postnatal exposure. Parental NOAELs were lower or equivalent to 
developmental or offspring NOAELs. The developmental toxicity studies 
are designed to evaluate adverse effects on the developing organism 
resulting from maternal pesticide exposure during gestation. 
Reproduction studies provide information relating to effects from 
exposure to the pesticide on the reproductive capability of mating 
animals and data on systemic toxicity.
    FFDCA section 408 provides that EPA shall apply an additional 
tenfold margin of safety for infants and children in the case of 
threshold effects to account for prenatal and postnatal toxicity and 
the completeness of the data base unless, EPA determines that a 
different margin of safety will be safe for infants and children. 
Margins of safety are incorporated into EPA risk assessments either 
directly through use of a MOE analysis or through using uncertainty 
(safety) factors in calculating a dose level that poses no appreciable 
risk to humans. EPA believes that reliable data support using the 
standard uncertainty factor (usually 100 for combined interspecies and 
intraspecies variability) and not the additional tenfold MOE/
uncertainty factor when EPA has a complete data base under existing 
guidelines and when the severity of the effect in infants or children 
or the potency or unusual toxic properties of a compound do not raise 
concerns regarding the adequacy of the standard MOE/safety factor.
    Although developmental toxicity studies showed no increased 
sensitivity in fetuses as compared to maternal animals following in 
utero exposures in rats and rabbits, no increased sensitivity in pups 
as compared to adults was seen in the 2-generation reproduction 
toxicity study in rats, and the toxicology data base is complete as to 
core requirements, the EPA has determined that the additional safety 
factor for the protection of infants and children will be retained but 
reduced to 3X based on the following weight-of-the-evidence 
considerations relating to potential sensitivity and completeness of 
the data:
    i. There is concern for structure activity relationship. 
Imidacloprid, a chloronicotinyl compound, is an analog to nicotine and 
studies in the published literature suggests that nicotine, when 
administered causes developmental toxicity, including functional 
deficits, in animals and/or humans that are exposed in utero.
    ii. There is evidence that imidacloprid administration causes 
neurotoxicity following a single oral dose in the acute study and 
alterations in brain weight in rats in the 2-year carcinogenicity 
study.
    iii. The concern for structure activity relationship along with the 
evidence of neurotoxicity dictates the need of a developmental 
neurotoxicity study for assessment of potential alterations on 
functional development.
    Because a developmental neurotoxicity study potentially relates to 
both acute and chronic effects in both the mother and the fetus, EPA 
has applied the additional UF for FQPA for all population subgroups, 
and in both acute and chronic risk assessments.
    Based on the exposure assessments described above and on the

[[Page 41460]]

completeness and reliability of the toxicity data, it can be concluded 
that the dietary exposure estimates from all label and pending uses of 
imidacloprid are 13.44% of the aPAD at the 99.9th percentile and 2.7% 
of the cPAD for the most highly exposed population subgroup, children 
(1-6 yrs). Thus, Bayer concludes that there is a reasonable certainty 
that no harm will result from aggregate exposure to imidacloprid 
residues.

F. International Tolerances

    No CODEX maximum residue levels have been established for residues 
of imidacloprid on any crops at this time.
[FR Doc. 00-16765 Filed 7-3-00; 8:45 am]
BILLING CODE 6560-50-F


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