[Federal Register Volume 63, Number 181 (Friday, September 18, 1998)]
[Rules and Regulations]
[Pages 49837-49852]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-25085]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300717; FRL-6027-1]
RIN 2070-AB78


Imidacloprid; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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

SUMMARY: This regulation establishes tolerances for the combined 
residues of imidacloprid and its metabolites containing the 6-
chloropyridinyl moiety in or on sugar beets (tops, roots, molasses), 
barley (grain, straw, hay), wheat (grain, forage, straw, hay), as 
requested by Gustafson, Incorporated (PP 5F4584 and PP 4F4337); and 
cereal grains crop group (grain, forage, straw, hay, stover), sweet 
corn, safflower (seed, meal), legume vegetables crop group (seed, 
foliage), soybean meal, as requested by Bayer Corporation (PP 6F4765). 
Gustafson, Incorporated, and Bayer Corporation requested these 
tolerances under the Federal Food, Drug and Cosmetic Act (FFDCA), as 
amended by the Food Quality Protection Act of 1996.

DATES: This regulation is effective September 18, 1998. Objections and 
requests for hearings must be received by EPA on or before November 17, 
1998.
ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, OPP-300717, must be submitted to: Hearing Clerk 
(1900), Environmental Protection Agency, Rm. M3708, 401 M St., SW., 
Washington, DC 20460. Fees accompanying objections and hearing requests 
shall be labeled ``Tolerance Petition Fees'' and forwarded to: EPA 
Headquarters Accounting Operations Branch, OPP (Tolerance Fees), PO Box 
360277M, Pittsburgh, PA 15251. A copy of any objections and hearing 
requests filed with the Hearing Clerk identified by the docket control 
number, OPP-300717, must also be submitted to: Public Information and 
Records Integrity Branch, Information Resources and Services Division 
(7502C), Office of Pesticide Programs, Environmental Protection Agency, 
401 M St., SW., Washington, DC 20460. In person, bring a copy of 
objections and hearing requests to Rm. 119, Crystal Mall #2, 1921 
Jefferson Davis Hwy., Arlington, VA.
    A copy of objections and hearing requests filed with the Hearing 
Clerk may also be submitted electronically by sending electronic mail 
(e-mail) to: [email protected]. Copies of objections and 
hearing requests must be submitted as an ASCII file avoiding the use of 
special characters and any form of encryption. Copies of objections and 
hearing requests will also be accepted on disks in WordPerfect 5.1/6.1 
or ASCII file format. All copies of objections and hearing requests in 
electronic form must be identified by the docket control number OPP-
300717. No Confidential Business Information (CBI) should be submitted 
through e-mail. Electronic copies of objections and hearing requests on 
this rule may be filed online at many Federal Depository Libraries.


[[Page 49838]]


FOR FURTHER INFORMATION CONTACT: By mail: Peg Perreault, Registration 
Division 7505C, Office of Pesticide Programs, Environmental Protection 
Agency, 401 M St., SW., Washington, DC 20460. Office location, 
telephone number, and e-mail address: Crystal Mall #2, 1921 Jefferson 
Davis Hwy., Arlington, VA, 703-305-5417, e-mail: 
Perreault.P[email protected].

SUPPLEMENTARY INFORMATION: In the Federal Registers of June 25, 1997 
(62 FR 34261) (FRL-5719-6) and February 26, 1997 (62 FR 8731) (FRL-
5589-2), EPA issued notices pursuant to section 408 of the Federal 
Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(e) announcing the 
filing of pesticide petitions (PP 5F4584, PP 4F4337, Gustafson; and PP 
6F4765, Bayer) for tolerances by Gustafson, Incorporated, PO Box 
660065, Dallas, Texas 75255-0065; and Bayer Corporation, 8400 Hawthorn 
Road, PO Box 4913, Kansas City, MO 64120-0013. These notices included 
summaries of the petitions prepared by Gustafson, Incorporated, and 
Bayer Corporation, the registrants. There were no comments received in 
response to the notices of filing. The petitions requested that 40 CFR 
180.472(a) and (d) be amended by establishing tolerances for combined 
residues of the insecticide imidacloprid (1-[(6-chloro-3-pyridinyl) 
methyl]-N-nitro-2-imidazolidinimine) and its metabolites containing the 
6-chloropyridinyl moiety, all expressed as (1-[(6-chloro-3-pyridinyl) 
methyl]-N-nitro-2-imidazolidinimine), in or on sugar beets (tops) at 
0.5, roots at 0.05, molasses at 0.3 parts per million (ppm), barley 
(grain) at 0.05, straw at 0.5, hay at 0.5 ppm, wheat (grain) at 0.05, 
forage at 7.0, straw at 0.5, hay at 0.5 ppm 40 CFR 180.472(a); and 
cereal grains crop group - grain at 0.05, forage at 2.0, straw at 3.0, 
hay at 6.0, stover at 0.3 ppm, sweet corn (kernel plus cob with husk 
removed) at 0.05, safflower - seed at 0.05, meal at 0.5, legume 
vegetable crop group - seed at 0.3, foliage at 2.5, soybean meal at 0.5 
ppm (inadvertent or indirect residues, 40 CFR 180.472(d)).

I. Risk Assessment and Statutory Findings

    Section 408(b)(2)(A)(i) of the FFDCA allows EPA to establish a 
tolerance (the legal limit for a pesticide chemical residue in or on a 
food) only if EPA determines that the tolerance is ``safe.'' Section 
408(b)(2)(A)(ii) defines ``safe'' to mean that ``there is a reasonable 
certainty that no harm will result from aggregate exposure to the 
pesticide chemical residue, including all anticipated dietary exposures 
and all other exposures for which there is reliable information.'' This 
includes exposure through drinking water and in residential settings, 
but does not include occupational exposure. Section 408(b)(2)(C) 
requires EPA to give special consideration to exposure of infants and 
children to the pesticide chemical residue in establishing a tolerance 
and to ``ensure that there is a reasonable certainty that no harm will 
result to infants and children from aggregate exposure to the pesticide 
chemical residue. . . .''
    EPA performs a number of analyses to determine the risks from 
aggregate exposure to pesticide residues. For further discussion of the 
regulatory requirements of section 408 and a complete description of 
the risk assessment process, see the Final Rule on Bifenthrin Pesticide 
Tolerances (62 FR 62961, November 26, 1997) (FRL-5754-7).

II. Aggregate Risk Assessment and Determination of Safety

    Consistent with section 408(b)(2)(D), EPA has reviewed the 
available scientific data and other relevant information in support of 
this action. EPA has sufficient data to assess the hazards of 
imidacloprid and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for tolerances for the combined 
residues of imidacloprid and its metabolites containing the 6-
chloropyridinyl moiety in or on sugar beets (tops) at 0.5, roots at 
0.05, molasses at 0.3 parts per million (ppm), barley (grain) at 0.05, 
straw at 0.5, hay at 0.5 ppm, wheat grain at 0.05, forage at 7.0, straw 
at 0.5, hay at 0.5 ppm (40 CFR 180.472(a); and cereal grains crop group 
- grain at 0.05, forage at 2.0, straw at 3.0, hay at 6.0, stover at 0.3 
ppm, sweet corn (kernel plus cob with husk removed) at 0.05, safflower 
- seed at 0.05, meal at 0.5, legume vegetable crop group - seed at 0.3, 
foliage at 2.5, soybean meal at 0.5 ppm (40 CFR.180.472(d)). EPA's 
assessment of the dietary exposures and risks associated with 
establishing the tolerances follows.

A. Toxicological Profile

    EPA has evaluated the available toxicity data and considered its 
validity, completeness, and reliability as well as the relationship of 
the results of the studies to human risk. EPA has also considered 
available information concerning the variability of the sensitivities 
of major identifiable subgroups of consumers, including infants and 
children. The nature of the toxic effects caused by imidacloprid are 
discussed below.
    1. Acute toxicity. The following table contains a summary of the 
acute toxicity data for technical imidacloprid.

                                                                                                                
----------------------------------------------------------------------------------------------------------------
        Guideline Number               Study Type          MRIDs Nos.            Results       Toxicity Category
----------------------------------------------------------------------------------------------------------------
81-1                              Acute Oral           42055331            LD50 = 424 mg/kg                   II
                                                                            (M)                                 
                                                                           > 450 mg/kg (F)                      
----------------------------------------------------------------------------------------------------------------
81-2                              Acute Dermal         42055332            LD50 >5,000 mg/kg                  IV
----------------------------------------------------------------------------------------------------------------
81-3                              Acute Inhalation     42256317            LC50 > 5.33 mg/L                   IV
----------------------------------------------------------------------------------------------------------------
81-4                              Primary Eye          42055334            Non-irritant                       IV
                                   Irritation                                                                   
----------------------------------------------------------------------------------------------------------------
81-5                              Primary Skin         42055335            Non-irritant                       IV
                                   Irritation                                                                   
----------------------------------------------------------------------------------------------------------------
81-6                              Dermal               42055336            Non-sensitizer                     NA
                                   Sensitization                                                                
----------------------------------------------------------------------------------------------------------------
81-8                              Acute Neurotoxicity  41317301            NOAEL = Not                        NA
                                                       43285801             established                         
                                                                           LOEL = 42 mg/kg                      
                                                                            bwt/day                             
----------------------------------------------------------------------------------------------------------------

    The following table contains a summary of the acute toxicity of the 
end-use product (40.7% formulation) for imidacloprid (Gaucho 480F, EPA 
Reg. No. 7501-155).

[[Page 49839]]



                                                                                                                
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        Guideline Number               Study Type          MRIDs Nos.            Results       Toxicity Category
----------------------------------------------------------------------------------------------------------------
81-1                              Acute Oral/Rat       42857703            LD50 = 4687 mg/kg                 III
                                                                            (M)                                 
                                                                           4067 mg/kg (F)                       
----------------------------------------------------------------------------------------------------------------
81-2                              Acute Dermal/Rat     42857703            LD50 >5,050 mg/kg                  IV
----------------------------------------------------------------------------------------------------------------
81-3                              Acute Inhalation/    42256326            LC50 = 2.11 mg/L                   IV
                                   Rat                                      (M&F)                               
----------------------------------------------------------------------------------------------------------------
81-4                              Primary Eye          42857705            Irritation score:                  IV
                                   Irritation/Rabbit                       0.7 (1 hr.); 0.1                     
                                                                            (24 hr.)                            
                                                                           0.0 (48 hr.); 0.0                    
                                                                            (72 hr.)                            
----------------------------------------------------------------------------------------------------------------
81-5                              Primary Dermal       42256328            PIS: 0.0 (non-                     IV
                                   Irritation/Rabbit                        irritating)                         
----------------------------------------------------------------------------------------------------------------
81-6                              Dermal               42857707            Not a sensitizer                   NA
                                   Sensitization/                                                               
                                   Guinea Pig                                                                   
----------------------------------------------------------------------------------------------------------------

    2. 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 milligrams/kilograms (mg/
kg) body weight/day (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 no observable adverse effect level (NOAEL) was 
>1,000 mg/kg bwt/day; a lowest observable effect level (LOEL) was not 
established (MRID No. 42256329).
    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 LOEL 
was 1,000 ppm (63.3 and 69.3 mg/kg bwt/day in males and females, 
respectively) (MRID No. 43286401).
    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/m3 (MRID No. 422730-01).
    3. 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 LOEL 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 to the lack of toxicity at 1,250 ppm, a LOEL 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 LOEL (MRID No. 42273002).
    4. Carcinogenicity. In a combined chronic toxicity/carcinogenicity 
study, groups of Bor WISW rats (50/sex/dose) received imidacloprid 
(95.3%) at 0, 100, 300 or 900 ppm (0, 5.7, 16.9 or 51.3 mg/kg bwt/day 
in males and 0, 7.6, 24.9, or 73 mg/kg bwt/day in females, 
respectively) for 104 weeks. In another study, rats of the same strain 
(50/sex) received imidacloprid at 0 or 1,800 ppm (0, 102.6, and 143.7 
mg/kg bwt/day in males and females, respectively) for 104 weeks. For 
chronic toxicity, the NOAEL was 100 ppm (5.7 mg/kg bwt/day) and the 
LOEL was 300 ppm (16.9 mg/kg bwt/day) based on decreased body weight 
gains in females and increased thyroid lesions in males. There was no 
evidence of carcinogenicity in either sex (MRID No. 42256331 and 
42256332).
    In carcinogenicity study groups of B6C3F1 mice (50/sex/dose) were 
fed diets containing imidacloprid (95%) at 0, 100, 330 or 1,000 ppm (0, 
20, 66, or 208 mg/kg bwt/day in males and 0, 30, 104 or 274 mg/kg bwt/
day in females, respectively) for 2 years. In a supplementary study 
conducted to evaluate the adequacy of the high dose tested in the main 
study, the same strain of mice (50/sex) received 0 or 2,000 ppm (414 
and 424 mg/kg bwt/day in males and females, respectively) for the same 
time period. For chronic toxicity, the NOAEL was 1,000 ppm (208 mg/kg 
bwt/day). The LOEL was 2,000 ppm (414 mg/kg bwt/day) based on decreased 
body weight gain, food consumption, and water consumption. There was no 
evidence of carcinogenicity in either sex (MRID No. 42256335 and 
42256336).
    5. 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 LOEL was 10 mg/kg bwt/day 
(LDT) based on decreased body weight gain; a NOAEL was not established. 
For developmental toxicity, the NOAEL was 30 mg/kg bwt/day and the LOEL 
was 100 mg/kg bwt/day based on increased wavy ribs (MRID No. 42256338).
    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 LOEL 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 LOEL was 72 mg/kg bwt/day based on 
decreased fetal body weight, increased resorptions, and increased 
skeletal abnormalities (MRID No. 42256339).

[[Page 49840]]

    6. Reproductive toxicity. 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) 
(MRID No. 42256340, Doc. No. 010537). For parental/systemic/
reproductive toxicity, the NOAEL was 250 ppm (18.3 mg/kg bwt/day) and 
the LOEL 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 
EPA/OPP/HED Hazard Identification Assessment Review Committee (HIARC) 
recommended that the Data Evaluation Record should be revised to 
indicate the parental/systemic/reproductive NOAEL and LOEL to be 250 
and 700 ppm, respectively, based upon the body weight decrements 
observed in both sexes in both generations.
    7. Mutagenicity. As shown below, mutagenicity studies have 
demonstrated that imidacloprid is non-mutagenic both in vivo and in 
vitro.

                                                                        
------------------------------------------------------------------------
              Assay                   MRIDs Nos.            Results     
------------------------------------------------------------------------
Ames-Salmonella                   42256363            Negative up to    
                                                       5,500 g/
                                                       plate            
------------------------------------------------------------------------
Recombination assay - yeast       42256353            Negative for      
                                                       crossing-over in 
                                                       yeast up to      
                                                       10,000 g         
------------------------------------------------------------------------
Chromosomal aberration - in vivo  42256344            Negative for      
                                                       chromosome       
                                                       breakage up to   
                                                       2,000 g/
                                                       mL               
------------------------------------------------------------------------
Chromosomal aberration - in       42256345            Positive at 500   
 vitro                                                 g/mL -S9
                                                       and 1,300 g/mL +S9, both 
                                                       toxic doses      
------------------------------------------------------------------------
Sister Chromatid assay - in vivo  42256346            Negative up to    
                                                       2,000 g/
                                                       mL               
------------------------------------------------------------------------
Cytogenetics -CHO cells - in      42256342            Negative for      
 vitro                                                 inducing forward 
                                                       mutation in CHO  
                                                       (mammalian) cells
                                                       treated up to    
                                                       1,222 g/
                                                       mL               
------------------------------------------------------------------------
Micronucleus - mouse              42256366            Negative up to    
                                                       (toxic) 50 mg/kg 
                                                       (ip)             
------------------------------------------------------------------------
DNA repair test                   42256353            Negative for      
                                                       crossing-over in 
                                                       yeast up to      
                                                       10,000 g         
------------------------------------------------------------------------
HGPRT assay - CHO                 42256365            Negative up to    
                                                       2,000 g/
                                                       mL               
------------------------------------------------------------------------

    8. Dermal absorption. No dermal absorption studies are available. 
However, this is not a concern since occupational and residential risk 
assessments are not required for dermal exposure due to the lack of 
dermal or systemic toxicity (following single or repeated dermal 
application of imidacloprid to laboratory animals).
    9. Neurotoxicity. In an acute neurotoxicity study, groups of 
Sprague-Dawley rats (18/sex/dose) were given a single oral 
administration of imidacloprid (97.6%) in 0.5% methyl cellulose with 
0.4% Tween 80 in deionized water at 0, 42, 151, or 307 mg/kg. 
Parameters evaluated included: clinical pathology (6/sex/dose); 
Functional Observation Battery (FOB) measurements (12/sex/dose); and 
neuropathology (6/sex/dose). FOB measurements were made approximately 
90 minutes post dosing, and on days 7 and 14. Motor activity 
measurements were made at approximately 2.5 hours post dosing.
    At 307 mg/kg bwt/day, 4/18 males and 10/18 females died and both 
sexes of rats at this dose exhibited decreased numbers of rears, grip 
strength (forelimb and hindlimb) and response to stimuli (auditory, 
touch, or tail pinch) as well as increased gait abnormalities, righting 
reflex impairments and body temperatures. These symptoms regressed by 
day 5. At 151 mg/kg bwt/day, cage side FOB assessments revealed tremors 
in one male and one female and red nasal staining in one male. On the 
day of dosing, a dose-related decrease in total session motor activity 
was observed in males at 151 mg/kg bwt/day (25% decrease) and 307 mg/kg 
bwt/day (73%) and in females at all dose levels with the decreases (25, 
48, and 81%, respectively at 42, 151, and 307 mg/kg bwt/day) reaching 
statistical significance (p <0.05) at 151 and 307 mg/kg bwt/day dose 
levels. Decreases in motor activity were seen at all time intervals. 
Total session locomotor activity was also decreased to about the same 
percentage difference but statistical significance was not reported. On 
days 7 and 14, decreases (not statistically significant) were still 
observed in motor and locomotor activity in surviving high-dose males. 
The LOEL was 42 mg/kg based on the decrease in motor and locomotor 
activities observed in females; a NOAEL was not established (MRID No. 
41317031 and 43285801).
    10. Other-toxicological considerations. EPA is requiring a 
developmental neurotoxicity study (Guideline No. 83-6) for 
imidacloprid. The following information was considered in the weight-
of-evidence evaluation:
    i. Imidacloprid is a neurotoxic chemical. Evidence of functional 
neurotoxicity was seen in the acute neurotoxicity study where a single 
oral dose caused a dose-related decrease in motor activity in all dosed 
females, including a 25% decrease at the lowest dose tested (42 mg/kg 
bwt/day).
    ii. Imidacloprid is a nicotine analog and is expected to act as a 
nicotinic agonist.
    iii. With this class of chemical, there is no readily available 
biomarker (e.g., cholinesterase inhibition) for assessment of subtle 
neurotoxic effects.
    iv. In the 1993 2-year chronic study in rats, significant 
alterations of brain weight were noted in males and females at 900 ppm 
(51.3 and 73 mg/kg bwt/day in males and females, respectively).
    v. There has been no assessment of the delayed neurotoxicity study 
in the hen.
    vi. A review of the literature suggests that nicotine causes 
developmental toxicity, including functional deficits, in animals and/
or humans exposed in utero.
    11. Metabolism. The metabolism of NTN 33893 (imidacloprid) in rats 
was reported in seven studies (85-1), and found to be Core Minimum. 
They are:
    i. Methylene-[14C] Imidacloprid: Metabolism Part of the 
General

[[Page 49841]]

Metabolism Study in the Rat (MRID No. 42256354).
    ii. [14C]-NTN 33893: Biokinetic Part of the General 
Metabolism Study in the Rat (MRID No. 42256356).
    iii. [Imidazolidine-4,5-14C] Imidacloprid: Investigation 
of the Biokinetic Behavior and Metabolism in the Rat (MRID No. 
42256357).
    iv. Imidacloprid - WAK 3839: Comparison of the Biokinetic Behavior 
and Metabolism in the Rat Following Single Oral Dosage and 
Investigation of the Metabolism after Chronic Feeding of Imidacloprid 
to Rats and Mice (MRID No. 42256373).
    v. A Liquid Chromatographic Method for the Determination of NTN 
33893 in Aqueous Dose Mixtures (MRID No. 42256359).
    vi. A Liquid Chromatographic Method for the Determination of NTN 
33893 in Inhalation Chamber Atmospheres (MRID No. 42256358).
    vii. [14C]-NTN 33893: Investigations on the Distribution 
of Total Radioactivity in the Rat by Whole-Body Autoradiography (MRID 
No. 42256355).
    These data 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 of the parent compound rendering NTN 35884. A 
comparison between [methylene-14C]-imidacloprid and 
[imidazolidine-4,5-14C]-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.
    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.

B. Toxicological Endpoints

    1. Acute toxicity. The endpoint selected for acute dietary risk 
assessment is based on neurotoxicity characterized by decreases in 
motor or locomotor activity in female rats at 42 mg/kg bwt/day (LOEL) 
in an acute neurotoxicity study (MRID No. 41370301 and 43285801). A 
NOAEL was not established in this study.
    Although developmental toxicity studies showed no increases in 
sensitivity in fetuses as compared to maternal animals following in 
utero exposures in rats and rabbits, and no increased sensitivity in 
pups as compared to adults and offspring in the two generation 
reproductive toxicity study in rats, and the toxicology data base is 
complete with respect to core requirements, the Agency determined that 
an acceptable acute dietary exposure (food plus water) of 33.3% or less 
of the acute reference dose (RfD) for all population subgroups is 
required based on the following weight-of-the-evidence considerations:
    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.
    Conventionally, when a LOEL from the critical study is used for 
risk assessment, an additional UF will be applied. For acute risk 
assessment with imidacloprid, however, the Agency determined that the 
3x factor used for FQPA (as discussed under section II.E. of this 
unit), is adequate to cover the use of the LOEL as well because of the 
low confidence in the endpoint based on the minimal nature of the 
effect (decreased motor activity only in females), the fact that this 
effect was seen in adult rats, and because the same effect was not seen 
in the subchronic toxicity study following repeated doses.
    2. Short - and intermediate-term toxicity. No dermal or systemic 
toxicity was seen in a 21-day dermal toxicity study in rabbits 
following repeated dermal applications of imidacloprid at 1,000 mg/kg 
bwt/day (limit-dose) for 3 weeks. In addition, an inhalation endpoint 
has not been established for imidacloprid. In a 28-day rat inhalation 
study in which rats were exposed 6 hours/day, 5 days/week, the NOAEL 
was 5.5 mg/m3. Imidacloprid also has a relatively low vapor 
pressure (6.9 x 10-9 torr). Since available data show no 
potential for dermal or inhalation toxicity from short- and 
intermediate-term exposure to imidacloprid, a risk assessment is not 
required.
    3. Chronic toxicity. EPA has established the RfD for imidacloprid 
at 0.057 mg/kg/day. This RfD is based on the results of a combined 
chronic toxicity/ carcinogenicity study, in which groups of Bor WISW 
rats (50/sex/dose) received imidacloprid (95.3%) at 0, 100, 300, or 900 
ppm (0, 5.7, 16.9 or 51.3 mg/kg bwt/day in males and 0, 7.6, 24.9, or 
73 mg/kg bwt/day in females, respectively) for 104 weeks. For chronic 
toxicity, the NOAEL was 100 ppm (5.7 mg/kg bwt/day in males and 7.6 mg/
kg bwt/day in females) and the LOEL was 300 ppm (16.9 mg/kg bwt/day in 
males and 24.9 mg/kg bwt/day in females) based on decreased body weight 
gains in females and increased thyroid lesions in males. Organ weight 
changes were observed in both sexes of rats at a dose of 900 ppm. There 
was no evidence of carcinogenicity in either sex. Dose/endpoint for 
establishing the RfD: NOAEL = 5.7 mg/kg bwt/day based on decreased body 
weight gains in females and increased number of thyroid lesions in 
males at 16.9 mg/kg bwt/day (LOEL). This is the endpoint selected for 
chronic dietary risk assessment.
Uncertainty Factor (UF): 10x for inter-species variation plus 10x for 
intra-species variation
Chronic RfD: The RfD is calculated as follows: Chronic RfD = NOAEL 
 UF = 5.7 mg/kg bwt/day  100 = 0.057 mg/kg bwt/
day
    The Agency determined that the additional uncertainty factor (UF) 
for FQPA (reduced to 3x as discussed under Units II.B.1. and II.E. of 
this preamble) applies to all population subgroups and also applies to 
both acute and chronic risk. Application of the additional 3x safety 
factor for enhanced susceptibility of infants and children to the 
Chronic RfD results in an acceptable chronic dietary exposure (food 
plus water) of 33.3% or less of the Chronic RfD for all population 
subgroups.
    4. Carcinogenicity. Imidacloprid has been classified as a Group E 
chemical,

[[Page 49842]]

no evidence of carcinogenicity in humans. A cancer risk assesment is 
not required.

C. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40 
CFR 180.472) for the combined residues of imidacloprid and its 
metabolites containing the 6-chloropyridinyl moiety in or on a variety 
of raw agricultural commodities and meat at 0.3 ppm, milk 0.1 ppm, 
poultry 0.05 ppm, and egg 0.02 ppm. Risk assessments were conducted by 
EPA to assess dietary exposures and risks from imidacloprid as follows:
    i. Acute exposure and risk. Acute dietary risk assessments are 
performed for a food-use pesticide if a toxicological study has 
indicated the possibility of an effect of concern occurring as a result 
of a one day or single exposure. As previously stated, the endpoint 
selected for assessment of acute dietary risk is 42 mg/kg bwt/day 
(LOEL). The UFs are 10x for inter-, 10x for intra-species variations 
and 3x for FQPA. Application of the 3X safety factor for enhanced 
susceptibility of infants and children to the acute RfD results in an 
acceptable acute dietary exposure (food plus water) of 33.3% or less of 
the acute RfD for all population subgroups. An acute dietary risk 
assessment is required for all population subgroups.
    This acute dietary (food) risk assessment used the Theoretical 
Maximum Residue Contribution (TMRC) which assumes tolerance level 
residues and 100% crop-treated. The DRES System was used for this acute 
dietary exposure analysis. The analysis evaluates individual food 
consumption as reported by respondents in the USDA 1977-78 Nationwide 
Food Consumption Survey (NFCS) and accumulates exposure to the chemical 
for each commodity. Resulting exposure values and percent of the acute 
RfD utilized are shown below.

                                                                        
------------------------------------------------------------------------
      Acute Dietary (Food Only) Exposure and Risk for Imidacloprid      
-------------------------------------------------------------------------
                                    Exposure @ 99th                     
       Population Subgroup         Percentile (mg/kg   Percent Acute RfD
                                       bwt/day)                         
------------------------------------------------------------------------
U.S. Population (48 states)       0.050               12%               
------------------------------------------------------------------------
Infants (< 1 yr)                  0.10                24%               
------------------------------------------------------------------------
Children (1-6 yrs)                0.10                24%               
------------------------------------------------------------------------
Females (13+ yrs)                 0.040               9.5%              
------------------------------------------------------------------------
Males (13+ yrs)                   0.050               12%               
------------------------------------------------------------------------

    Values for the 99th percentile are considered to be conservative as 
EPA policy dictates exposure estimates from as low as the 95th 
percentile may be utilized for risk estimates from acute DRES runs not 
using Monte Carlo Analysis. Thus, these results should be viewed as a 
very conservative risk estimate; refinement using anticipated residue 
values and percent crop-treated information in conjunction with Monte 
Carlo analysis would result in a lower estimate of acute dietary 
exposure.
    ii. Chronic exposure and risk. The chronic dietary exposure 
analysis from food sources was conducted using the reference dose 
(Chronic RfD) of 0.057 mg/kg bwt/day. The FQPA Safety Factor for 
enhanced sensitivity of infants and children was reduced to 3x. The 
FQPA factor was applied in the risk assessment for all population 
subgroups. Application of the 3x safety factor for enhanced 
susceptibility of infants and children to the Chronic RfD results in an 
acceptable chronic dietary exposure (food plus water) of 33.3% or less 
of the Chronic RfD for all population subgroups.
    A tolerance is established for residues of imidacloprid and its 
metabolites containing the 6-chloropyridinyl moiety, all expressed as 
parent, in or on canola seed at 0.05 ppm. Canola seed per se is not a 
human food item. Canola seed is processed into canola oil which is 
consumed by humans. Because canola is not listed as a commodity in 
DRES, EPA has estimated the dietary exposure from imidacloprid treated 
canola seed in the following manner:
Consumption (g/kg/day) x Residue (mg/kg) = Exposure (mg/kg bwt/day)
    The consumption value for canola was taken as the U.S. production 
volume (877 million lbs or 3.98 x 1011 g) divided by the 
U.S. population in the 1977-1978 USDA Food Consumption Survey (240 
million) to get grams of canola consumed per year. Further division was 
done to estimate consumption per day for an average person (body weight 
58.9 kg) to get consumption per person per day. Tolerance level 
residues and 100% crop treated were assumed. The estimated exposure 
resulting from the established imidacloprid tolerance on canola (0.05 
ppm) is 3.86 x 10-6 mg/kg bwt/day. This exposure represents 
<1.0% of the RfD. EPA concludes the dietary exposure from the 
imidacloprid tolerance on canola is not significant.
    This approach to estimating the exposure due to consumption of 
imidacloprid treated canola results in a conservative exposure 
assessment. EPA notes that the consumption of corn oil by the general 
US population in the 1977-1978 USDA Food Consumption Survey was only 
0.022 g/kg bwt/day. The consumption estimate for canola is 
approximately 3.5 times this value.
    In conducting this chronic dietary (food) risk assessment, EPA 
used: (1) tolerance level residues for the proposed tolerances of these 
petitions and all other commodities with published, pending, permanent 
or time-limited, imidacloprid tolerances; and (2) percent crop-treated 
information on some of these crops. Thus, this risk assessment should 
be viewed as partially refined. Further refinement using anticipated 
residue values and additional percent crop treated information would 
result in a lower estimate of chronic dietary exposure. The DRES System 
was used for this chronic dietary exposure analysis. The analysis 
evaluates individual food consumption as reported by respondents in the 
USDA 1977-1978 Nationwide Food Consumption Survey (NFCS) and 
accumulates exposure to the chemical for each commodity.
    The RACs (Raw Agricultural Commodities) and tolerances, used in the 
dietary risk assessment, were derived from 40 CFR 180.472 and EPA's 
Tolerance Index System.
    The following table summarizes the estimated dietary exposures for 
the U.S. population, those population subgroups that include infants 
and children, and

[[Page 49843]]

all population subgroups with risk estimates above that of the U.S. 
Population.

                                                                        
------------------------------------------------------------------------
     Chronic Dietary Exposure (Food Only) and Risk for Imidacloprid     
-------------------------------------------------------------------------
                                    Exposure (mg/kg     Percent Chronic 
            Subgroup                   bwt/day)               RfD       
------------------------------------------------------------------------
U.S. Population (48 States)       0.0039              6.8%              
------------------------------------------------------------------------
Nursing Infants (< 1 year old)    0.0032              5.6%              
------------------------------------------------------------------------
Non-nursing Infants (<1 year      0.011               19%               
 old)                                                                   
------------------------------------------------------------------------
Children (1 to 6 years old)       0.0081              14%               
------------------------------------------------------------------------
Children (7 to 12 years old)      0.0057              10%               
------------------------------------------------------------------------
U.S. Population - Fall Season     0.0040              7.0%              
------------------------------------------------------------------------
U.S. Population Winter Season     0.0040              7.0%              
------------------------------------------------------------------------
Northeast Region                  0.0040              7.0%              
------------------------------------------------------------------------
Western Region                    0.0041              7.2%              
------------------------------------------------------------------------
Hispanics                         0.0043              7.5%              
------------------------------------------------------------------------
Non-Hispanic Others               0.0042              7.4%              
------------------------------------------------------------------------

    Section 408(b)(2)(F) states that the Agency may use data on the 
actual percent of food treated for assessing chronic dietary risk only 
if the Agency can make the following findings: (1) that the data used 
are reliable and provide a valid basis to show what percentage of the 
food derived from such crop is likely to contain such pesticide 
residue; (2) that the exposure estimate does not underestimate exposure 
for any significant subpopulation group; and (3) if data are available 
on pesticide use and food consumption in a particular area, the 
exposure estimate does not understate exposure for the population in 
such area. In addition, the Agency must provide for periodic evaluation 
of any estimates used. To provide for the periodic evaluation of the 
estimate of percent crop treated as required by the section 
408(b)(2)(F), EPA may require registrants to submit data on percent 
crop treated.
    The Agency used percent crop treated (PCT) information as follows. 
A routine chronic dietary exposure analysis for imidacloprid was based 
on likely maximum percent of crop treated as follows: 6% grapefruits, 
3% oranges, 13% other citrus, 19% apples, 2% pears, 11% grapes, 30% 
eggplants/peppers, 32% head lettuce, 21% cole crops, 15% melons, 10% 
tomatoes, 6% cotton.
    The Agency believes that the three conditions listed above have 
been met. With respect to finding (1), EPA finds that the PCT 
information described above for imidacloprid is reliable and has a 
valid basis, The Agency has utilized the latest statistical data from 
RFF (Resources For The Future), DOANE, and USDA, the best available 
sources for such information. Concerning findings (2) and (3), regional 
consumption information and consumption information for significant 
subpopulations is taken into account through EPA's computer-based model 
for evaluating the exposure of significant subpopulations including 
several regional groups. Use of this consumption information in EPA's 
risk assessment process ensures that EPA's exposure estimate does not 
understate exposure for any significant subpopulation group and allows 
the Agency to be reasonably certain that no regional population is 
exposed to residue levels higher than those estimated by the Agency. 
Other than data available through national food consumption surveys, 
EPA does not have available information on the consumption of food 
bearing imidacloprid in a particular area.
    2. From drinking water. There are no Maximum Contaminant Levels 
(MCL) or Health Advisory (HA) levels established for residues of 
imidacloprid in drinking water. This information was furnished by the 
EPA Safe Drinking Water Hotline (1-800-426-4791) on June 16, 1998.
    Information in EPA's Pesticide Environmental Fate One Line Summary 
data base (last update May 6, 1997) suggests that imidacloprid is 
persistent and mobile.
    EPA's ``Pesticides in Ground Water Database'' (EPA 734-12-92-001, 
9/92) has no entry for imidacloprid.
    i. Acute exposure and risk--a. Acute exposure. Estimated maximum 
concentrations of imidacloprid in surface and ground water are 50.9 and 
0.605 ppb, respectively.
    EPA used PRZM1 (Pesticide Root Zone Model - simulates the transport 
of a pesticide off the agricultural field) and EXAMS (Exposure Analysis 
Modeling System - simulates fate and transport of a pesticide in 
surface water) models to estimate concentrations of imidacloprid 
residues in surface water. It should be noted that PRZM1/EXAMS models 
were designed for use in ecological risk assessment. They are not ideal 
tools for use in drinking water risk assessment. PRZM1/EXAMS could 
overestimate actual drinking water concentrations. Thus, these models 
should be considered a screening tool.
    EPA used the SCI-GROW (Screening Concentration In Ground Water) 
model to estimate the concentration of imidacloprid residues in ground 
water. SCI-GROW is a prototype model for estimating ``worst case'' 
ground water concentrations of pesticides. SCI-GROW is biased in that 
studies where the pesticide is not detected in ground water are not 
included in the data set. Thus, it is not expected that SCI-GROW 
estimates would be exceeded.
    b. Acute risk. EPA has calculated drinking water levels of concern 
(DWLOC's) for acute exposure to imidacloprid in surface and ground

[[Page 49844]]

water for various population subgroups. The DWLOC's for acute exposure 
to imidacloprid are summarized below.

                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           Drinking Water Levels of Concern for Acute Exposure to Imidacloprid                                          
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                     Dietary Exposure1 (mg/    Max. Exposure from                                Daily Water                            
        Population Subgroup                kg bwt/day)        Water (mg/kg bwt/day)     Bodyweight (kg)      Consumption (Liters)   DWLOC (g/L)
--------------------------------------------------------------------------------------------------------------------------------------------------------
U.S. Population (48 States)          0.050                   0.090                   70                     2                      3,200                
--------------------------------------------------------------------------------------------------------------------------------------------------------
Females (13+ years)                  0.040                   0.10                    60                     2                      3,000                
--------------------------------------------------------------------------------------------------------------------------------------------------------
Children (1 - 6 years)               0.010                   0.13                    10                     1                      1,300                
--------------------------------------------------------------------------------------------------------------------------------------------------------
199th percentile                                                                                                                                        

    To calculate the DWLOC relative to an acute toxicity endpoint, the 
acute dietary food exposure (from DRES) was subtracted from one-third 
the Acute RfD to obtain the acceptable acute exposure to imidacloprid 
in drinking water. The value of one-third the Acute RfD was utilized to 
account for the FQPA Safety Factor of 3x. DWLOCs were then calculated 
using default body weights and drinking water consumption figures.
    ii. Short-term exposure and risk--a. Short-term exposure. Estimated 
maximum concentrations of imidacloprid in surface and ground water are 
50.9 and 0.605 g/mL, respectively. EPA utilized PRZM1 and 
EXAMS to generate these estimates. Descriptions of these models are 
above.
    b. Short-term risk. EPA has calculated a drinking water level of 
concern (DWLOC) for short-term exposure to imidacloprid in surface and 
ground water for the population subgroup children, 1 to 6 years old. 
This DWLOC is for short-term exposure to imidacloprid from home garden 
and turf uses. A DWLOC for short-term exposure from imidacloprid pet 
uses was not determined as the exposure level from the home garden and 
turf uses is higher than that of the pet uses. Thus, the DWLOC for the 
imidacloprid pet uses will be higher than that of the home garden and 
turf uses. The DWLOC for short-term exposure to imidacloprid is 
summarized below.

                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                        Drinking Water Levels of Concern for Short-Term Exposure to Imidacloprid                                        
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                     Total Exposure1 (mg/kg    Max. Exposure from                                Daily Water                            
        Population Subgroup                 bwt/day)          Water (mg/kg bwt/day)     Bodyweight (kg)      Consumption (Liters)   DWLOC (g/L)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Children (1 - 6 years)               0.080                   0.060                   10                     1                      600                  
--------------------------------------------------------------------------------------------------------------------------------------------------------
1Total Exposure = sum of exposures from chronic food plus home turf and garden uses.                                                                    

    The DWLOC for short-term exposure to imidacloprid was calculated 
relative to the acute RfD which was utilized for estimating risk for 
short-term oral exposure to imidacloprid. To calculate the DWLOC for 
short-term exposure relative to an acute toxicity endpoint, the sum of 
chronic dietary food exposure (from DRES) plus the oral exposure from 
imidacloprid home garden and turf uses was subtracted from one-third 
the Acute RfD to obtain the acceptable short-term exposure to 
imidacloprid in drinking water. The value of one-third the Acute RfD 
was utilized to account for the FQPA Safety Factor of 3x. DWLOCs were 
then calculated using default body weights and drinking water 
consumption figures.
    iii. Chronic exposure and risk--a. Chronic exposure. The estimated 
average concentration of imidacloprid in surface water (for chronic 
exposure) is 19.1 g/mL. An estimated average concentration of 
imidacloprid in ground water was not provided. EPA used PRZM1 and EXAMS 
models to estimate chronic environmental concentrations of imidacloprid 
residues in surface water.
    b. Chronic risk. EPA has calculated DWLOCs for chronic (non-cancer) 
exposure to imidacloprid in surface and ground water for various 
population subgroups. The DWLOC's for chronic exposure to imidacloprid 
are summarized below.

                                                                                                                                                        
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                          Drinking Water Levels of Concern for Chronic Exposure to Imidacloprid                                         
---------------------------------------------------------------------------------------------------------------------------------------------------------
                                      Dietary Exposure (mg/    Max. Exposure from                                Daily Water                            
        Population Subgroup                kg bwt/day)        Water (mg/kg bwt/day)     Bodyweight (kg)      Consumption (Liters)   DWLOC (g/L)
--------------------------------------------------------------------------------------------------------------------------------------------------------
U.S. Population (48 States)          0.0039                  0.015                   70                     2                      530                  
--------------------------------------------------------------------------------------------------------------------------------------------------------
Females (13+ yrs., pregnant)         0.0036                  0.015                   60                     2                      460                  
--------------------------------------------------------------------------------------------------------------------------------------------------------

[[Page 49845]]

                                                                                                                                                        
Non-nursing Infants                  0.011                   0.0080                  10                     1                      80                   
--------------------------------------------------------------------------------------------------------------------------------------------------------

    To calculate the DWLOC for chronic (non-cancer) exposure relative 
to a chronic toxicity endpoint, the chronic dietary food exposure (from 
DRES) was subtracted from one-third the chronic RfD to obtain the 
acceptable chronic (non-cancer) exposure to imidacloprid in drinking 
water. The value of one-third of the RfD was utilized to account for 
the FQPA Safety Factor of 3x. DWLOCs were then calculated using default 
body weights and drinking water consumption figures.
    A DWLOC for chronic (cancer) exposure was not calculated as 
imidacloprid has been classified as a Group E chemical (no evidence of 
carcinogenicity).
    3. From non-dietary exposure. Imidacloprid is currently registered 
for use on the following residential non-food sites: ornamentals (e.g., 
flowering and foliage plants, ground covers, turf, lawns, et al.), 
tobacco, golf courses, walkways, recreational areas, household or 
domestic dwellings (indoor/outdoor), and cats/dogs. Available data do 
not demonstrate that imidacloprid has either dermal or inhalation 
toxicity potential, therefore, non-dietary dermal and inhalation 
exposure assessments are not required. Since available data show no 
toxicity from short-term exposure via the dermal or inhalation route, 
the Agency feels there is no contribution to toxicity from these routes 
of exposure, and no increase in aggregate risk is anticipated from this 
exposure. However, there is the potential for residential exposure via 
incidental non-dietary ingestion from treated lawns and gardens and 
incidental non-dietary ingestion by toddlers of pesticide residues on 
pets from hand-to-mouth transfer. Therefore, an increase in aggregate 
risk is anticipated from residential exposure via incidental non-
dietary ingestion and residential exposure and risk assessments are 
required for the use of imidacloprid in/on lawns and gardens and on 
pets.
    The product Premise, a termiticide, is also registered for 
residential use. It may be applied only by Pest Control Operators 
(PCOs) and only to inaccessible areas of homes or other buildings; 
therefore, oral exposure to children is not expected. There is 
potential for inhalation exposure; however, an inhalation endpoint has 
not been established and imidacloprid has a low vapor pressure (6.9 x 
10-9 torr). Since oral exposure to children is not expected 
and the Agency feels there is no contribution to toxicity from the 
inhalation route of exposure, no increase in aggregate risk is 
anticipated and a residential exposure assessment based upon the 
imidacloprid termiticide use is not required.
    i. Exposure and risk from incidental non-dietary ingestion from 
treated lawns and gardens. A summary of post-application exposure 
estimates and risk assessments are summarized in the table below. The 
post-application exposure scenarios for toddlers examined include:
     Incidental non-dietary ingestion of residues on lawns from 
hand-to-mouth transfer.
     Ingestion of pesticide-treated turfgrass.
     Incidental ingestion of soil from treated gardens.
    The calculations and assumptions utilized to determine these 
exposures are as per the Draft Standard Operating Procedures for 
Residential Exposure Assessments (December 18, 1997).

                                                                                                                                                                                                
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Post Application Exposure Estimates and Risk Assessments                                                                    
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                          DFRtb (g/   GRtc (g/   SRtd (g/   ADDe (mg/kg bwt/                                         
            Scenario                   Receptor          ARa (lb ai/A)           cm2)                cm2)                 g)                 day)          NOAEL (mg/kg/day)         MOEf       
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Hand-to-mouth for treated lawns   Toddler             0.4                 0.9                 --                  --                  0.07                42                  640               
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Turf-grass                        Toddler             0.4                 --                  0.9                 --                  0.0015              42                  28,000            
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Incidental Soil Ingestion         Toddler             0.4                 --                  --                  3                   0.000020            42                  2,100,000         
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
aAR,Application Rate                                                                                                                                                                            
bDFRt, Dislodgeable foliar residue (g/cm2)                                                                                                                                             
cGRt, Grass residue (g/cm2)                                                                                                                                                            
dSRt, Soil residue (g/g)                                                                                                                                                               
eADD, Average daily dose (mg/kg bwt/day) .                                                                                                                                                      
fMOE = NOAEL/ ADD (No NOAEL established, LOEL of 42 mg/kg bwt/day used)                                                                                                                         

    ii. Exposure and risk to toddlers from incidental non-dietary 
ingestion of pesticide residues on pets from hand-to-mouth transfer. 
Advantage 110 Flea Adulticide (EPA Reg. No. 011556-121) is a 5.0 mL 
vial that is applied to two locations on the dog (2.5 mL per 1 in 2). 
The method for assessing hand-to-mouth transfer in the Draft Standard 
Operating Procedures for Residential Exposure Assessments (December 18, 
1997) is intended for a complete body dip of the treated animal. 
Therefore, a modified approach was applied to estimate oral exposures. 
Assumptions and calculations used are as follows:
Assumptions:
     On the day of application it may be assumed that 20% 
(0.20) of the application rate is retained on the pets as dislodgeable 
residue. This value is

[[Page 49846]]

based on the professional judgement and experience of the EPA staff 
from the review of company-submitted data and is believed to be an 
upper-percentile assumption.
     It is assumed that 1% (0.01) of the available residues are 
transferred to the individuals who have contact with the treated 
animals. This is considered to be a conservative assumption in light of 
the very low percentage of the pet's total skin surface being treated. 
It should be noted that 10% (0.10) is recommended for complete pet dips 
in the Draft Standard Operating Procedures for Residential Exposure 
Assessments (December 18, 1997). This is the only deviation from the 
standard operating procedures.
     It was assumed that 100% of the residue on the hands of 
toddlers is ingested. This is considered to be a conservative 
assumption.
     Post application activities assessed on the same day that 
the pesticide is applied since it is assumed that toddlers could 
handle/touch pets immediately after application. This is considered a 
short-term oral exposure.
     Toddlers (age 3 years), used to represent the 1 to 6 year 
old age group, are assumed to weigh 15 kg.
     5.0 mL of product was used per application (EPA Reg. No. 
011556-121). Product contains 9.1% ai. Density of formulation is not 
given on label. Density of water was assumed for converting volume in 
mL to lb active ingredient (ai).
     This product represents high-end exposure among similar 
products containing imidacloprid given that it involves the highest 
volume of the active ingredient.
Calculations:
    The average daily dose (ADD = 0.058 mg/kg bwt/day) was calculated 
by multiplying the following: application rate (AR = 436 mg ai/day) x 
fraction of ai available on pet (F = 0.2) x fraction of residue 
transferred to the skin (T = 0.01), and dividing by bwt (15 kg).
    A margin of exposure (MOE) of 720 was calculated by dividing the 
NOAEL (42 mg/kg bwt/day) by the ADD (0.058 mg/kg). (NOAEL was not 
established, therefore acute dietary LOEL of 42 mg/kg bwt/day was 
used).
    The estimated MOE is 720 which is greater than the minimum required 
MOE of 300. Therefore, exposure via incidental non-dietary ingestion of 
imidacloprid residues on pets from hand-to-mouth transfer would not 
exceed EPA's level of concern. However, it should be noted that the 20% 
used for the fraction of active ingredient available on pet (F) and the 
1% used for the fraction of residue transferred to the skin (T) are 
estimates made by EPA given a lack of available data. The actual values 
may differ. It is recommended that the registrant submit a study to 
quantify dislodgeable residues on toddler's hands from pets treated 
with these types of products.
    4. Cumulative exposure to substances with common mechanism of 
toxicity. Section 408(b)(2)(D)(v) requires that, when considering 
whether to establish, modify, or revoke a tolerance, the Agency 
consider ``available information'' concerning the cumulative effects of 
a particular pesticide's residues and ``other substances that have a 
common mechanism of toxicity.''
    EPA does not have, at this time, available data to determine 
whether imidacloprid has a common mechanism of toxicity with other 
substances or how to include this pesticide in a cumulative risk 
assessment. Unlike other pesticides for which EPA has followed a 
cumulative risk approach based on a common mechanism of toxicity, 
imidacloprid does not appear to produce a toxic metabolite produced by 
other substances. For the purposes of this tolerance action, therefore, 
EPA has not assumed that imidacloprid has a common mechanism of 
toxicity with other substances. For information regarding EPA's efforts 
to determine which chemicals have a common mechanism of toxicity and to 
evaluate the cumulative effects of such chemicals, see the Final Rule 
for Bifenthrin Pesticide Tolerances (62 FR 62961, November 26, 1997).

D. Aggregate Risks and Determination of Safety for U.S. Population

    1. Acute risk--i. Food. The acute dietary (food) risk assessment 
used the TMRC. Resulting exposure values and percent of the acute RfD 
utilized are shown below.

                                                                        
------------------------------------------------------------------------
      Acute Dietary (Food Only) Exposure and Risk for Imidacloprid      
-------------------------------------------------------------------------
                                    Exposure @ 99th                     
       Population Subgroup         Percentile (mg/kg   Percent Acute RfD
                                       bwt/day)                         
------------------------------------------------------------------------
U.S. Population (48 states)       0.050               12%               
------------------------------------------------------------------------
Infants (< 1 yr)                  0.10                24%               
------------------------------------------------------------------------
Children (1-6 yrs)                0.10                24%               
------------------------------------------------------------------------
Females (13+ yrs)                 0.040               9.5%              
------------------------------------------------------------------------
Males (13+ yrs)                   0.050               12%               
------------------------------------------------------------------------

    For imidacloprid, it was determined that an acceptable acute 
dietary exposure (food plus water) of 33.3% or less of the acute RfD 
for all population subgroups is needed to protect the safety of all 
population subgroups. The estimated exposures for all population 
subgroups at the 99th percentile utilize less than 33.3% of the acute 
RfD.
    ii. Water. The estimated maximum concentrations of imidacloprid in 
surface and ground water (50.9 and 0.605 g/mL, respectively) 
are less than EPA's levels of concern for imidacloprid in drinking 
water (1,300, 3,000 and 3,200 g/mL) as a contribution to acute 
exposure. Therefore, taking into account the present uses and uses 
proposed in this action, EPA concludes with reasonable certainty that 
residues of imidacloprid in drinking water (when considered along with 
other sources of acute exposure for which EPA has reliable data) would 
not result in unacceptable levels of acute aggregate human health risk 
estimates at this time.
    EPA bases this determination on a comparison of estimated maximum 
concentrations of imidacloprid in surface water to back-calculated 
``levels of concern'' for imidacloprid in drinking water. These levels 
of concern in drinking water were determined after EPA has considered 
all other non-occupational/non-residential human exposures for which it 
has reliable data, including all current uses, and uses considered in 
this action. The estimates of imidacloprid in surface water are

[[Page 49847]]

derived from water quality models that use conservative assumptions 
(health-protective) regarding the pesticide transport from the point of 
application to surface and ground water. Because EPA considers the 
aggregate risk resulting from multiple exposure pathways associated 
with a pesticide's uses, levels of concern in drinking water may vary 
as those uses change. If new uses are added in the future, EPA will 
reassess the potential impacts of imidacloprid in drinking water as a 
part of the acute aggregate risk assessment process.
    Despite the potential for imidacloprid exposure from drinking 
water, EPA concludes that there is a reasonable certainty that no harm 
will result to infants, children, or adults from acute aggregate 
exposure to imidacloprid residues.
    2. Short- and intermediate-term risk. Short- and intermediate-term 
aggregate exposure takes into account chronic dietary food and water 
exposure (considered to be a background exposure level) plus indoor and 
outdoor residential exposure. Since dermal and inhalation exposure 
endpoints (short-term) were not identified due to the demonstrated 
absence of toxicity, no increase in aggregate risk is anticipated from 
dermal and inhalation exposure. Therefore, dermal and inhalation short-
term risk assessments are not required for imidacloprid.
    In addition to its food uses, imidacloprid is registered for use on 
turf, home gardens and pets. EPA has identified potential short-term 
oral exposures to toddlers for these uses. These exposures include the 
following scenarios:
     Incidental non-dietary ingestion of residues on lawns from 
hand-to-mouth transfer.
     Ingestion of pesticide-treated turfgrass.
     Incidental ingestion of soil from treated gardens.
     Incidental ingestion of pesticide residues on pets from 
hand-to-mouth transfer.
    According to current EPA policy, these exposures are considered to 
be short-term oral exposures. EPA does not expect incidental ingestion 
of pesticide residues on pets from hand-to-mouth transfer to occur 
during the same period as the exposures from the turf and home garden 
uses. Thus, we will consider these exposures in separate estimates of 
risk. The tables below summarize the short-term aggregate exposures for 
imidacloprid from turf and garden uses and from the pet use.
    A short-term oral endpoint was not identified for imidacloprid. 
According to current EPA policy, if an oral endpoint is needed for 
short-term risk assessment (for incorporation of food, water, or oral 
hand-to-mouth type exposures into an aggregate risk assessment), the 
acute oral endpoint (acute RfD = 0.42 mg/kg bwt/day) will be used to 
incorporate the oral component into aggregate risk. Short-term 
aggregate exposure is defined by EPA to be average food and water 
exposure (chronic exposure) plus residential exposure. The short-term 
risk estimates for the population subgroup Children, 1 to 6 years old, 
is summarized below. This population subgroup was chosen because it has 
the highest chronic food exposure and because toddlers have the highest 
exposure from the residential uses.

                                                                                                                
----------------------------------------------------------------------------------------------------------------
             Short-Term Aggregate Exposure and Risk (Includes Turf and Garden Uses of Imidacloprid)             
-----------------------------------------------------------------------------------------------------------------
                                     Chronic Food         Residential                                           
       Population Subgroup          Exposure (mg/kg    Exposure1 (mg/kg     Total Exposure2   Percent Acute RfD3
                                       bwt/day)            bwt/day)         (mg/kg bwt/day)                     
----------------------------------------------------------------------------------------------------------------
Children (1 to 6 years old)       0.0081              0.072               0.080               19%               
----------------------------------------------------------------------------------------------------------------
1Residential Exposure = Total of imidacloprid exposure from incidental ingestion of residues on lawns from hand-
  to-mouth transfer plus ingestion of pesticide-treated grass plus ingestion of soil from treated gardens.      
2Total Exposure = Chronic Food Exposure plus Residential Exposure.                                              
3Percent Acute RfD = Acute RfD (0.42 mg/kg bwt/day)/Total Exposure (mg/kg bwt/day) x 100%.                      


                                                                                                                
----------------------------------------------------------------------------------------------------------------
                  Short-Term Aggregate Exposure and Risk (Includes the Pet Use of Imidacloprid)                 
-----------------------------------------------------------------------------------------------------------------
                                     Chronic Food         Residential                                           
       Population Subgroup          Exposure (mg/kg    Exposure1 (mg/kg     Total Exposure2   Percent Acute RfD3
                                       bwt/day)            bwt/day)         (mg/kg bwt/day)                     
----------------------------------------------------------------------------------------------------------------
Children (1 to 6 years old)       0.0081              0.058               0.066               16%               
----------------------------------------------------------------------------------------------------------------
1Residential Exposure = Total of imidacloprid exposure from incidental ingestion of residues on pets from hand- 
  to-mouth transfer.                                                                                            
2Total Exposure = Chronic Food Exposure plus Residential Exposure.                                              
3Percent Acute RfD = Acute RfD (0.42 mg/kg bwt/day)/Total Exposure (mg/kg bwt/day) x 100%.                      

    The estimated maximum concentrations of imidacloprid in surface and 
ground water (50.9 and 0.605 g/mL, respectively) are less than 
EPA's level of concern for imidacloprid in drinking water (600 g/mL) as 
a contribution to short-term exposure from imidacloprid home garden, 
turf and pet uses. Therefore, taking into account the present uses and 
uses proposed in this action, EPA concludes with reasonable certainty 
that residues of imidacloprid in drinking water (when considered along 
with other sources of short-term exposure for which EPA has reliable 
data) would not result in unacceptable levels of short-term aggregate 
human health risk estimates at this time.
    EPA bases this determination on a comparison of estimated maximum 
concentrations of imidacloprid in surface water to the back-calculated 
``level of concern'' for imidacloprid in drinking water. The level of 
concern in drinking water was determined after EPA has considered all 
other non-occupational human exposures for which it has reliable data, 
including all current uses and uses considered in this action. The 
estimates of imidacloprid in surface and ground water are derived from 
water quality models that use conservative assumptions (health-
protective) regarding the pesticide transport from the point of 
application to surface and ground water. Because EPA considers the 
aggregate risk resulting from multiple exposure pathways associated 
with a pesticide's uses, levels of concern in drinking water may vary 
as those uses change. If new

[[Page 49848]]

uses are added in the future, EPA will reassess the potential impacts 
of imidacloprid in drinking water as a part of the a short-term 
aggregate risk assessment process.
    As noted above, potential short-term exposure from drinking water 
is at a level well below EPA's level of concern. EPA concludes the 
short-term aggregate risk to the highest exposed population subgroup 
from home garden, turf, and pet uses of imidacloprid does not exceed 
our level of concern.
    3. Chronic risk. The chronic dietary (food only) risk assessment 
utilized the following exposure assumptions: (i) tolerance level 
residues for the proposed tolerances of these petitions and all other 
commodities with published or pending, permanent or time-limited, 
imidacloprid tolerances; and (ii) percent crop-treated information on 
some of these crops. Using the exposure assumptions described above, 
EPA has concluded that aggregate exposure to imidacloprid from food 
will utilize 6.8% of the Chronic RfD for the U.S. population. The major 
identifiable subgroup with the highest aggregate exposure is infants 
(discussed below in section E). EPA generally has no concern for 
exposures below 100% of the RfD because the RfD represents the level at 
or below which daily aggregate dietary exposure over a lifetime will 
not pose appreciable risks to human health. Despite the potential for 
exposure to imidacloprid in drinking water, EPA does not expect the 
aggregate exposure to exceed 100% of the RfD.
    4. Aggregate cancer risk for U.S. population. Imidacloprid has been 
classified as a Group E chemical, no evidence of carcinogenicity for 
humans. Therefore, a cancer risk assessment is not required.
    5. Determination of safety. Based on these risk assessments, EPA 
concludes that there is a reasonable certainty that no harm will result 
to the U.S. population from aggregate exposure to imidacloprid 
residues.

E. Aggregate Risks and Determination of Safety for Infants and Children

    1. Safety factor for infants and children--i. In general. In 
assessing the potential for additional sensitivity of infants and 
children to residues of imidacloprid, EPA 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. of this unit. 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 
post-natal 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 pre-and post-natal 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 inter- and intra-species 
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 Agency 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:
    a. 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.
    b. 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.
    c. 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.
    ii. Conclusion. The toxicology data base for imidacloprid is 
complete with respect to core requirements; however, a developmental 
neurotoxicity study (Guideline No. 83-6) is required. Exposure data is 
estimated based on data that reasonably accounts for potential 
exposures; however, a study to quantify dislodgeable residues on 
toddler's hands from pets treated with imidacloprid is required.
    2. Acute risk. Aggregate acute risks for the entire U.S. population 
and for population subgroups, including infants and children, are 
discussed in section D.1. of this unit.
    3. Short- and intermediate-term risk. Aggregate short- and 
intermediate-term risks for the entire U.S. population and for 
population subgroups, including infants and children are discussed in 
section D.2. of this unit.
    4. Chronic risk. Using the exposure assumptions described above, 
EPA has concluded that aggregate exposure to imidacloprid from food 
will utilize 5.6% of the RfD for nursing infants, 19% of the RfD for 
non-nursing infants, 14% of the RfD for children 1 to 6 years old, and 
10% of the RfD for children 7 to 12 years old. EPA generally has no 
concern for exposures below 100% of the RfD because the RfD represents 
the level at or below which daily aggregate dietary exposure over a 
lifetime will not pose appreciable risks to human health. Despite the 
potential for exposure to imidacloprid in drinking water, EPA does not 
expect the aggregate exposure to exceed 100% of the RfD.
    5. Determination of safety. Based on these risk assessments, EPA 
concludes that there is a reasonable certainty that no harm will result 
to infants and children from aggregate exposure to imidacloprid 
residues.

III. Other Considerations

A. Metabolism in Plants and Animals

    1. Nature of the residue in plants and livestock. Data concerning 
the metabolism of imidacloprid in apples, potatoes, tomatoes, eggplant,

[[Page 49849]]

cottonseed, field corn, ruminants and poultry have previously been 
submitted. The nature of imidacloprid residues in plants and animals is 
adequately understood. The residue of concern is imidacloprid and its 
metabolites containing the 6-chloropyridinyl moiety, all expressed as 
parent, as specified in 40 CFR 180.472 (September 14, 1994, PP 4F4337 
and September 23, 1997, PP 6F4765).
    2. Confined accumulation in rotational crops. Data concerning the 
metabolism of imidacloprid in rotational crops was previously 
submitted. The nature of the residue in rotational crops is adequately 
understood and is nearly identical to that identified in the primary 
crops. The residue of concern in rotational crops is imidacloprid and 
its metabolites containing the 6-chloropyridinyl moiety, all expressed 
as parent (September 23, 1997, PP 6F4765).

B. Analytical Enforcement Methodology

    Adequate enforcement methods are available for determination of the 
regulated imidacloprid residue in plant (Bayer GC/MS Method 00200 and 
Bayer HPLC-UV Confirmatory Method 00357) and animal (Bayer GC/MS Method 
00191) commodities. These methods have successfully completed EPA 
Tolerance Method Validation, and are awaiting publication in PAM II 
(November 8, 1994 and April 13, 1995, PP 5F4415, June 17, 1996, PP 
5F4480). In the interim, these methods are available from: Calvin 
Furlow, PRRIB, IRSD (7502C), Office of Pesticide Programs, 
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460. 
Office location and telephone number: Rm. 101FF, Crystal Mall #2, 1921 
Jefferson Davis Hwy., Arlington, VA, (703-305-5229).
    Bayer Corporation has previously submitted adequate multiresidue 
method (MRM) recovery data for imidacloprid and its olefin, hydroxy, 
guanidine, and 6-chloronicotininc acid metabolites through FDA's 
Protocols A through E. Imidacloprid and its metabolites were not 
recoverable by these methods. These data have been forwarded to FDA and 
we expect them to be published in PAM, Vol. I, Appendix I in a future 
update. Additional MRM recovery data are not required (June 18, 1993, 
PP 3F4169).

C. Magnitude of Residues

    1. Crop field trials. The results of the previously submitted 
wheat, barley, and sugar beet field trials support the proposed 
tolerances for combined residues of imidacloprid and its regulable 
metabolites as follows (March 6, 1998, PP 4F4337):

                                                                        
------------------------------------------------------------------------
                                                    Proposed Tolerance  
             Crop                  Commodity              (ppm)         
------------------------------------------------------------------------
Beets, Sugar                   tops                                  0.5
                               roots                                0.05
                               molasses                              0.3
------------------------------------------------------------------------
Barley                         grain                                0.05
                               straw                                 0.5
                               hay                                   0.5
------------------------------------------------------------------------
Wheat                          grain                                0.05
                               forage                                7.0
                               straw                                 0.5
                               hay                                   0.5
------------------------------------------------------------------------

Residue data for aspirated grain fractions were not required for this 
seed treatment use (September 14, 1994, PP 4F4337).
    2. Field accumulation in rotational crops. The results of the 
previously submitted rotational crop field trials support the proposed 
tolerances for inadvertent or indirect combined residues of 
imidacloprid and its regulable metabolites as follows (September 23, 
1997, PP 6F4765):

                                                                        
------------------------------------------------------------------------
      Crop Group or Crop           Commodity      Tolerance Level (ppm) 
------------------------------------------------------------------------
Cereal Grains (Crop Group)     grain                                0.05
------------------------------------------------------------------------
Forage, Fodder and Straw of    forage                                2.0
 Cereal Grains Crop Group      straw                                 3.0
                               hay                                   6.0
                               stover                                0.3
------------------------------------------------------------------------
Sweet Corn                     K+CWHR                               0.05
------------------------------------------------------------------------
Safflower                      seed                                 0.05
                               meal                                  0.5
------------------------------------------------------------------------
Legume Vegetables (Crop        seed                                  0.3
 Group)                                                                 
------------------------------------------------------------------------
Foliage of Legume Vegetables   foliage                               2.5
 (Crop Group)                                                           
------------------------------------------------------------------------
Soybean                        meal                                  0.5
------------------------------------------------------------------------
K+CWHR = Kernel plus cob with husk removed.                             


[[Page 49850]]

    3. Magnitude of the residue in processed food/feed--i. Wheat. The 
results of a previously submitted wheat processing study showed that 
residues of imidacloprid and its metabolites are not expected to 
concentrate into the processed products of wheat. The study utilized a 
5x exaggerated application rate (September 14, 1994 and May 16, 1995, 
PP 4F4337).
    ii. Sugar beets. The results of a previously submitted sugar beet 
processing study (2.7x exaggerated application rate) showed that 
residues of imidacloprid and its metabolites are not expected to 
concentrate into dehydrated pulp. However, the results did show 
residues are expected to concentrate into sugar beet molasses. A 
tolerance of 0.3 ppm is adequate for residues of imidacloprid and its 
metabolites in sugar beet molasses (September 14, 1994 and May 16, 
1995, PP 4F4337).
    iii. Barley. Processing data for barley were not required for this 
seed treatment use (September 14, 1994, PP 4F4337).
    iv. Field corn. The results of a previously submitted field corn 
processing study showed that residues of imidacloprid and its 
metabolites are not expected to concentrate into the processed products 
of field corn. The study utilized exaggerated application rates of 2.5x 
and 4x (February 19, 1998, PP 6F4765).
    v. Safflower. A safflower processing study has not been submitted. 
The petitioner has indicated that they intend to conduct a safflower 
processing study. This deficiency is not resolved. A safflower 
processing study for imidacloprid is required. EPA recommends in favor 
of the proposed tolerances for imidacloprid and its metabolites in/on 
safflower seed and meal provided the requirement for a safflower 
processing study is made a condition of the registration of 
imidacloprid on safflower. The proposed tolerances are based upon a 
maximum residue level of <0.05 ppm (estimated to be approximately 0.03 
ppm) for total imidacloprid residues in safflower seed and a 
theoretical maximum concentration factor of 9.1x for safflower meal 
(September 23, 1997 and February 19, 1998, PP 6F4765).
    vi. Soybeans. A soybean processing study has not been submitted. 
The petitioner has proposed establishing a permanent tolerance for the 
combined residues of imidacloprid and its metabolites containing the 6-
chloropyridinyl moiety in soybean meal at 0.5 ppm in lieu of providing 
a soybean processing study. This request is based upon a maximum 
residue level of 0.2 ppm for total imidacloprid residues in soybean 
seed and a theoretical maximum concentration factor of 2.2x for soybean 
meal. EPA has considered this issue and has concluded that the 
requirement for a soybean processing study should be made a condition 
of the registration of imidacloprid on soybeans. Thus, a soybean 
processing study is required. The proposed tolerances for imidacloprid 
and its metabolites for soybean seed and meal are adequate pending 
submission of the soybean processing study (February 19, 1998, PP 
6F4765).
    4. Magnitude of secondary residues in meat, milk, poultry eggs--i. 
Ruminants. A ruminant feeding study was previously submitted. EPA has 
estimated the maximum imidacloprid dietary burden from proposed and 
established imidacloprid tolerances. The total dietary burden from our 
worst case diet for dairy cattle is approximately 20 ppm. The total 
dietary burden from our worst case diet for beef cattle is 
approximately 12 ppm. Tolerances are established for the combined 
residues of imidacloprid and its metabolites containing the 6-
chloropyridinyl moiety, expressed as imidacloprid, in ruminant fat, 
meat, and meat byproducts at 0.3 ppm and in milk at 0.1 ppm. EPA 
concludes the established tolerances for imidacloprid and its 
metabolites in ruminant commodities will not be exceeded as a result of 
additional dietary burden from the tolerances proposed in these 
petitions (September 21, 1993, PP 3F4169 and March 6, 1998, PP 4F4337).
    ii. Poultry. A poultry feeding study was previously submitted. EPA 
has estimated the maximum imidacloprid dietary burden for poultry from 
proposed and established imidacloprid tolerances. The total dietary 
burden from our worst case diet for poultry is approximately 2.2 ppm. 
Tolerances are established for the combined residues of imidacloprid 
and its metabolites containing the 6-chloropyridinyl moiety, expressed 
as imidacloprid, in poultry fat, meat and meat byproducts at 0.05 ppm 
and in eggs at 0.02 ppm. EPA concludes the established tolerances for 
imidacloprid and its metabolites in poultry commodities will not be 
exceeded as a result of additional dietary burden from the tolerances 
proposed in these petitions (September 21, 1993, PP 3F4169 and March 6, 
1997, PP 4F4337).

D. International Residue Limits

    There are no established CODEX, Canadian, or Mexican residue limits 
for imidacloprid in/on the crop groups cereal grains, legume vegetables 
and the foliage of legume vegetables; and the crops sweet corn, 
safflower, wheat, barley and sugar beets. Thus, harmonization of the 
proposed tolerances with CODEX, Canada, and Mexico is not an issue for 
these petitions.

IV. Conclusion

    Therefore, the tolerances are established for the combined residues 
of imidacloprid (1-[(6-chloro-3-pyridinyl) methyl]-N-nitro-2-
imidazolidinimine) and its metabolites containing the 6-chloropyridinyl 
moiety, all expressed as (1-[(6-chloro-3-pyridinyl) methyl]-N-nitro-2-
imidazolidinimine) in or on sugar beets -tops at 0.5, roots at 0.05, 
molasses at 0.3 parts per million (ppm), barley - grain at 0.05, straw 
at 0.5, hay at 0.5 ppm, wheat - grain at 0.05, forage at 7.0, straw at 
0.5, hay at 0.5 ppm (40 CFR 180.472(a)); and cereal grains crop group - 
grain at 0.05, forage at 2.0, straw at 3.0, hay at 6.0, stover at 0.3 
ppm, sweet corn (K+CWHR) at 0.05, safflower - seed at 0.05, meal at 
0.5, legume vegetable crop group seed at 0.3, foliage at 2.5, soybean 
meal at 0.5 ppm (inadvertent or indirect residues, 40 CFR 180.472(d)).

V. Objections and Hearing Requests

    The new FFDCA section 408(g) provides essentially the same process 
for persons to ``object'' to a tolerance regulation issued by EPA under 
new section 408(e) and (l)(6) as was provided in the old section 408 
and in section 409. However, the period for filing objections is 60 
days, rather than 30 days. EPA currently has procedural regulations 
which govern the submission of objections and hearing requests. These 
regulations will require some modification to reflect the new law. 
However, until those modifications can be made, EPA will continue to 
use those procedural regulations with appropriate adjustments to 
reflect the new law.
    Any person may, by November 17, 1998, file written objections to 
any aspect of this regulation and may also request a hearing on those 
objections. Objections and hearing requests must be filed with the 
Hearing Clerk, at the address given above (40 CFR 178.20). A copy of 
the objections and/or hearing requests filed with the Hearing Clerk 
should be submitted to the OPP docket for this rulemaking. The 
objections submitted must specify the provisions of the regulation 
deemed objectionable and the grounds for the objections (40 CFR 
178.25). Each objection must be accompanied by the fee prescribed by 40 
CFR 180.33. If a hearing is requested,

[[Page 49851]]

the objections must include a statement of the factual issues on which 
a hearing is requested, the requestor's contentions on such issues, and 
a summary of any evidence relied upon by the requestor (40 CFR 178.27). 
A request for a hearing will be granted if the Administrator determines 
that the material submitted shows the following: There is genuine and 
substantial issue of fact; there is a reasonable possibility that 
available evidence identified by the requestor would, if established, 
resolve one or more of such issues in favor of the requestor, taking 
into account uncontested claims or facts to the contrary; and 
resolution of the factual issues in the manner sought by the requestor 
would be adequate to justify the action requested (40 CFR 178.32). 
Information submitted in connection with an objection or hearing 
request may be claimed confidential by marking any part or all of that 
information as Confidential Business Information (CBI). Information so 
marked will not be disclosed except in accordance with procedures set 
forth in 40 CFR part 2. A copy of the information that does not contain 
CBI must be submitted for inclusion in the public record. Information 
not marked confidential may be disclosed publicly by EPA without prior 
notice.

VI. Public Record and Electronic Submissions

    EPA has established a record for this rulemaking under docket 
control number OPP-300717 (including any comments and data submitted 
electronically). A public version of this record, including printed, 
paper versions of electronic comments, which does not include any 
information claimed as CBI, is available for inspection from 8:30 a.m. 
to 4 p.m., Monday through Friday, excluding legal holidays. The public 
record is located in Rm. 119 of the Public Information and Records 
Integrity Branch, Information Resources and Services Division (7502C), 
Office of Pesticide Programs, Environmental Protection Agency, Crystal 
Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
    Electronic comments may be sent directly to EPA at:
    [email protected].


    Electronic comments must be submitted as an ASCII file avoiding the 
use of special characters and any form of encryption.
    The official record for this rulemaking, as well as the public 
version, as described above will be kept in paper form. Accordingly, 
EPA will transfer any copies of objections and hearing requests 
received electronically into printed, paper form as they are received 
and will place the paper copies in the official rulemaking record which 
will also include all comments submitted directly in writing. The 
official rulemaking record is the paper record maintained at the 
Virginia address in ``ADDRESSES'' at the beginning of this document.

VII. Regulatory Assessment Requirements

A. Certain Acts and Executive Orders

    This final rule establishes tolerances for imidacloprid under FFDCA 
section 408(d) in response to a petition submitted to the Agency. The 
Office of Management and Budget (OMB) has exempted these types of 
actions from review under Executive Order 12866, entitled ``Regulatory 
Planning and Review'' (58 FR 51735, October 4, 1993). This final rule 
does not contain any information collections subject to OMB approval 
under the Paperwork Reduction Act (PRA), 44 U.S.C. 3501 et seq., or 
impose any enforceable duty or contain any unfunded mandate as 
described under Title II of the Unfunded Mandates Reform Act of 1995 
(UMRA) (Pub. L. 104-4). Nor does it require any special considerations 
as required by Executive Order 12898, entitled ``Federal Actions to 
Address Environmental Justice in Minority Populations and Low-Income 
Populations (59 FR 7629, February 16, 1994), or require OMB review in 
accordance with Executive Order 13045, entitled Protection of Children 
from Environmental Health Risks and Safety Risks (62 FR 19885, April 
23, 1997). In addition, since tolerances and exemptions that are 
established on the basis of a petition under FFDCA section 408(d), such 
as the tolerances for imidacloprid in this final rule, do not require 
the issuance of a proposed rule, the requirements of the Regulatory 
Flexibility Act (RFA) (5 U.S.C. 601 et seq.) do not apply. 
Nevertheless, the Agency has previously assessed whether establishing 
tolerances, exemptions from tolerances, raising tolerance levels, or 
expanding exemptions might adversely impact small entities and 
concluded, as a generic matter, that there is no adverse economic 
impact. The factual basis for the Agency's generic certification for 
tolerance actions published on May 4, 1981 (46 FR 24950) and was 
provided to the Chief Counsel for Advocacy of the Small Business 
Administration.

B. Executive Order 12875

    Under Executive Order 12875, entitled ``Enhancing Intergovernmental 
Partnerships'' (58 FR 58093, October 28, 1993), EPA may not issue a 
regulation that is not required by statute and that creates a mandate 
upon a State, local or Tribal government, unless the Federal government 
provides the funds necessary to pay the direct compliance costs 
incurred by those governments. If the mandate is unfunded, EPA must 
provide to OMB a description of the extent of EPA's prior consultation 
with representatives of affected State, local and Tribal governments, 
the nature of their concerns, copies of any written communications from 
the governments, and a statement supporting the need to issue the 
regulation. In addition, Executive Order 12875 requires EPA to develop 
an effective process permitting elected officials and other 
representatives of State, local and Tribal governments ``to provide 
meaningful and timely input in the development of regulatory proposals 
containing significant unfunded mandates.''
    Today's rule does not create an unfunded Federal mandate on State, 
local or Tribal governments. The rule does not impose any enforceable 
duties on these entities. Accordingly, the requirements of section 1(a) 
of Executive Order 12875 do not apply to this rule.

C. Executive Order 13084

    Under Executive Order 13084, entitled ``Consultation and 
Coordination with Indian Tribal Governments'' (63 FR 27655, May 19, 
1998), EPA may not issue a regulation that is not required by statute, 
that significantly or uniquely affects the communities of Indian tribal 
governments, and that imposes substantial direct compliance costs on 
those communities, unless the Federal government provides the funds 
necessary to pay the direct compliance costs incurred by the Tribal 
governments. If the mandate is unfunded, EPA must provide OMB, in a 
separately identified section of the preamble to the rule, a 
description of the extent of EPA's prior consultation with 
representatives of affected Tribal governments, a summary of the nature 
of their concerns, and a statement supporting the need to issue the 
regulation. In addition, Executive Order 13084 requires EPA to develop 
an effective process permitting elected and other representatives of 
Indian tribal governments ``to provide meaningful and timely input in 
the development of regulatory policies on matters that

[[Page 49852]]

significantly or uniquely affect their communities.''
    Today's rule does not significantly or uniquely affect the 
communities of Indian tribal governments. This action does not involve 
or impose any requirements that affect Indian Tribes. Accordingly, the 
requirements of section 3(b) of Executive Order 13084 do not apply to 
this rule.

VIII. Submission to Congress and the Comptroller General

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. This rule is not a 
``major rule'' as defined by 5 U.S.C. 804(2).

List of Subjects in 40 CFR Part 180

    Environmental protection, Administrative practice and procedure, 
Agricultural commodities, Pesticides and pests, Reporting and 
recordkeeping requirements.
    Dated: September 9, 1998.
James Jones,
Director, Registration Division, Office of Pesticide Programs.
    Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

    1. The authority citation for part 180 continues to read as 
follows:

    Authority: 21 U.S.C. 346a and 371.

Sec. 180.472 [Amended]

    2. Section 180.472 is amended by adding the commoditiy wheat (hay) 
to the table in paragraph (a) and revising the following entries to 
paragraphs (a) and (d) to read as follows:
    (a)  *  *  *  

                                                                        
------------------------------------------------------------------------
                                                             Expiration/
                   Commodity                     Parts per    Revocation
                                                  million        date   
------------------------------------------------------------------------
                                                                        
                      *      *      *      *      *                     
Barley (grain)................................         0.05         None
Barley (hay)..................................          0.5         None
Barley (straw)................................          0.5         None
                                                                        
                      *      *      *      *      *                     
Beets, sugar (tops)...........................          0.5         None
Beets, sugar (roots)..........................         0.05         None
Beets, sugar, molasses........................          0.3         None
                                                                        
                      *      *      *      *      *                     
Wheat (forage)................................          7.0         None
Wheat (grain).................................         0.05         None
Wheat (hay)...................................          0.5         None
Wheat (straw).................................          0.5         None
------------------------------------------------------------------------

    *    *    *    *    *
    (d)  *  *  *

                                                                        
------------------------------------------------------------------------
                                                             Expiration/
                   Commodity                     Parts per    Revocation
                                                  million        date   
------------------------------------------------------------------------
Cereal grains crop group (grain)..............         0.05         None
Foliage of legume vegetables crop group                                 
 (foliage)....................................          2.5         None
Forage, fodder, and straw of cereal grains                              
 crop group (forage)..........................          2.0         None
Forage, fodder, and straw of cereal grains                              
 crop group (hay).............................          6.0         None
Forage, fodder, and straw of cereal grains                              
 crop group (stover)..........................          0.3         None
Forage, fodder, and straw of cereal grains                              
 crop group (straw)...........................          3.0         None
Legume vegetables crop group (seed)...........          0.3         None
Safflower (meal)..............................          0.5         None
Safflower (seed)..............................         0.05         None
Soybean (meal)................................          0.5         None
Sweet corn (kernel plus cob with husk removed)         0.05         None
                                                                        
                      *      *      *      *      *                     
------------------------------------------------------------------------


FR Doc. 98-25085 Filed 9-17-98; 8:45 am
BILLING CODE 6560-50-F