![[logo] US EPA](http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
Imidacloprid; Pesticide Tolerances for Emergency Exemptions
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: January 20, 1999 (Volume 64, Number 12)]
[Rules and Regulations]
[Page 3037-3044]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr20ja99-12]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300771; FRL 6051-6]
RIN 2070-AB78
Imidacloprid; Pesticide Tolerances for Emergency Exemptions
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
-----------------------------------------------------------------------
SUMMARY: This regulation establishes time-limited tolerances for
residues of imidacloprid in or on Legume Vegetables (Crop Group 6, 40
CFR 180.41(c)(6)) and Strawberries. This action is in response to EPA's
granting of emergency exemptions under section 18 of the Federal
Insecticide, Fungicide, and Rodenticide Act authorizing use of the
pesticide on legumes and strawberries. This regulation establishes
maximum permissible levels for residues of imidacloprid in these food
commodities pursuant to section 408(l)(6) of the Federal Food, Drug,
and Cosmetic Act, as amended by the Food Quality Protection Act of
1996. The tolerances will expire and are revoked on June 30, 2000.
DATES: This regulation is effective January 20, 1999. Objections and
requests for hearings must be received by EPA on or before March 22,
1999.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [OPP-300771], 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),
P.O. 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-300771], 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, CM #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: opp-docket@epamail.epa.gov. 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-
300771]. 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.
FOR FURTHER INFORMATION CONTACT: By mail: Andrea Beard, 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) 308-9356; e-mail:
beard.andrea@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: EPA, on its own initiative, pursuant to
section 408(e) and (l)(6) of the Federal Food, Drug, and Cosmetic Act
(FFDCA), 21 U.S.C. 346a(e) and (l)(6), is establishing a tolerance for
residues of the insecticide imidacloprid (1-[(6-chloro-3-
pyridinyl)methyl]-N-nitro-2-imidazolidinimine), in or on legume
vegetables and strawberries, at 1.0 and 0.1 part per million (ppm),
respectively. These tolerances will expire and are revoked on 6/30/00.
EPA will publish a document in the Federal Register to remove the
revoked tolerances from the Code of Federal Regulations.
I. Background and Statutory Authority
The Food Quality Protection Act of 1996 (FQPA) (Pub. L. 104-170)
was signed into law August 3, 1996. FQPA amends both the Federal Food,
Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 301 et seq., and the Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRA), 7 U.S.C. 136 et
seq. The FQPA amendments went into effect immediately. Among other
things, FQPA amends FFDCA to bring all EPA pesticide tolerance-setting
activities under a new section 408 with a new safety standard and new
procedures. These activities are described below and discussed in
greater detail in the final rule establishing the time-limited
tolerance associated with the emergency exemption for use of
propiconazole on sorghum (61 FR 58135, November 13, 1996) (FRL-5572-9).
New 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.''
Section 18 of FIFRA authorizes EPA to exempt any Federal or State
agency from any provision of FIFRA, if EPA determines that ``emergency
conditions exist which require such exemption.'' This provision was not
amended by FQPA. EPA has established regulations governing such
emergency exemptions in 40 CFR part 166.
Section 408(l)(6) of the FFDCA requires EPA to establish a time-
limited tolerance or exemption from the requirement for a tolerance for
pesticide chemical residues in food that will result from the use of a
pesticide under an emergency exemption granted by EPA under section 18
of FIFRA. Such tolerances can be established without providing notice
or period for public comment.
Because decisions on section 18-related tolerances must proceed
before EPA reaches closure on several policy issues relating to
interpretation and implementation of the FQPA, EPA does not intend for
its actions on such tolerance to set binding precedents for the
application of section 408 and the new safety standard to other
tolerances and exemptions.
[[Page 3038]]
II. Emergency Exemption for Imidacloprid on Legume Vegetables and
Strawberries and FFDCA Tolerances
The State of Florida requested a specific exemption for use of
imidacloprid on legume vegetables to control the silverleaf whitefly.
The state of California also requested a specific exemption for use of
imidacloprid on strawberries to control the silverleaf whitefly. Both
Florida and California stated that an emergency situation is present
due to this recently introduced pest, its devastating effects on many
fruit and vegetable crops, and its resistance to registered
alternatives. The Applicants state that this pest can have devastating
effects on growers' production and revenue. EPA has authorized under
FIFRA section 18 the use of imidacloprid on Legume Vegetables and
Strawberries for control of silverleaf whitefly in Florida and
California, respectively. After having reviewed the submissions, EPA
concurs that emergency conditions exist for these states.
As part of its assessment of these emergency exemptions, EPA
assessed the potential risks presented by residues of imidacloprid in
or on legume vegetables and strawberries. In doing so, EPA considered
the new safety standard in FFDCA section 408(b)(2), and EPA decided
that the necessary tolerance under FFDCA section 408(l)(6) would be
consistent with the new safety standard and with FIFRA section 18.
Consistent with the need to move quickly on the emergency exemptions in
order to address urgent non-routine situations and to ensure that the
resulting food is safe and lawful, EPA is issuing these tolerances
without notice and opportunity for public comment under section 408(e),
as provided in section 408(l)(6). Although these tolerances will expire
and are revoked on 6/30/00, under FFDCA section 408(l)(5), residues of
the pesticide not in excess of the amounts specified in the tolerances
remaining in or on legume vegetables and strawberries after that date
will not be unlawful, provided the pesticide is applied in a manner
that was lawful under FIFRA, and the residues do not exceed a level
that was authorized by these tolerances at the time of that
application. EPA will take action to revoke these tolerances earlier if
any experience with, scientific data on, or other relevant information
on this pesticide indicate that the residues are not safe.
Because these tolerances are being approved under emergency
conditions EPA has not made any decisions about whether imidacloprid
meets EPA's registration requirements for use on legume vegetables and
strawberries or whether permanent tolerances for these uses would be
appropriate. Under these circumstances, EPA does not believe that these
tolerances serve as a basis for registration of imidacloprid by a State
for special local needs under FIFRA section 24(c). Nor do these
tolerances serve as the basis for any State other than Florida or
California to use this pesticide on the respective crops under section
18 of FIFRA without following all provisions of section 18 as
identified in 40 CFR part 166. For additional information regarding the
emergency exemptions for imidacloprid, contact the Agency's
Registration Division at the address provided above.
III. Aggregate Risk Assessment and Determination of Safety
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).
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 time-limited tolerances for
residues of imidacloprid and its metabolites containing the 6-
chloropyridinyl moiety, all expressed as parent, on legume vegetables
and strawberries at 1.0 and 0.1 ppm, respectively. 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. Based on the available acute toxicity data, OPP
has determined that the lowest observed effect level (LOEL) of 42
milligrams per kilogram body weight per day (mg/kg/bwt/day) from the
neurotoxicity study in rats should be used to assess risk from acute
toxicity. There was no observed adverse effect level (NOAEL) in the
study. Decreased motor activity in female rats was observed at the
LOEL. Using the uncertainty factors (UFs) of 10X for inter- and 10X for
intra-species variations, the acute Reference Dose (RfD) is 0.42 mg/kg/
day. This risk assessment is required for all population subgroups.
2. Short - and intermediate - term toxicity. OPP has determined
that available data do not demonstrate that imidacloprid has dermal or
inhalation toxicity potential. Therefore, short-term or intermediate-
term dermal and inhalation risk assessments, for occupational and
residential exposure scenarios, are not required. However, a short-term
aggregate risk assessment (oral exposure) is required for hand-to-mouth
residential exposure, and the acute toxicological endpoint, as
described above, is used for this risk assessment. Incorporating the 3X
uncertainty factor, as described below, an MOE of 300 or greater would
be acceptable.
3. Chronic toxicity. EPA had established the RfD for imidacloprid
at 0.057 mg/kg/day. This RfD is based on a standard uncertainty factor
(UF) of 100, and the NOAEL of 5.7 mg/kg/day from a combined chronic
toxicity/carcinogenicity study in rats, which demonstrated increased
number of thyroid lesions in male rats and decreased body weight gains
in female rats. For chronic dietary risk assessment, the Agency
determined that the FQPA uncertainty factor could be reduced to 3X and
should be applied to all population subgroups. This determination is
based on the weight-of-the-evidence considerations relating to
potential sensitivity and completeness of the data, specifically, in
regard to developmental neurotoxicity. This determination is further
explained below under section III(D)(v) of this document. Because a
developmental neurotoxicity study potentially relates to both acute and
chronic effects in both the mother and the fetus, the 3X UF for FQPA is
being applied for all population subgroups, and both acute and chronic
risk. Therefore, for the purposes of this risk assessment, dietary
exposure must not be above 33.3% of the RfD, to make the finding of
reasonable certainty of no harm.
4. Carcinogenicity. Using its Guidelines for Carcinogen Risk
Assessment published September 24, 1986 (51 FR 33992), EPA has
classified imidacloprid as a ``Group E'' chemical (no evidence of
carcinogenicity for
[[Page 3039]]
humans) based on the results of carcinogenicity studies in two species.
The doses tested are adequate for identifying a cancer risk, and thus,
a cancer risk assessment is not required.
B. Exposures and Risks
1. From food and feed uses. Tolerances have been established (40
CFR 180.472) for the residues of imidacloprid (1-[(6-chloro-3-
pyridinyl)methyl]-N-nitro-2-imidazolidinimine) and its metabolites, in
or on a variety of raw agricultural commodities, ranging from 0.02 ppm
in/on eggs to 15 ppm in/on raisin waste. Existing meat/milk/poultry
tolerances are adequate to cover any secondary residues which may occur
as a result of feeding legume products; secondary residues are not
expected to occur from strawberries, as they are not a significant
livestock feed item. 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. An acute dietary risk assessment for
imidacloprid is required for all population subgroups. The acute
dietary risk assessment used the Theoretical Maximum Residue
Contribution (TMRC, tolerance level residues and 100% crop treated);
the tolerances used for legumes and strawberries were 1.0 and 0.1 ppm,
respectively. The Novigen Dietary Exposure Evaluation Model (DEEM)
analysis was used and this analysis evaluates individual food
consumption as reported by respondents in the USDA Continuing Surveys
of Food Intake by Individuals conducted in 1989 through 1992. The model
accumulates exposure to the chemical for each commodity and expresses
risk as a function of dietary exposure. Resulting exposure values at
the 99th percentile and percentage of the acute RfD are shown below.
Values for the 99th percentile are considered to be conservative as OPP
policy dictates exposure estimates from as low as the 95th percentile
may be utilized for risk estimates from acute DEEM runs. Thus, these
results are viewed as conservative estimates, and refinement using
anticipated residue values and percent crop treated information, in
conjunction with a Monte Carlo analysis, would result in lower
estimates of acute dietary exposure and risk. The subgroups listed in
the table below are the U.S. population, and those for infants and
children. There are no other subgroups (adult) for which the percentage
of the Acute RfD occupied is greater than that occupied by the subgroup
U.S. Population (48 states).
------------------------------------------------------------------------
Exposure @
99th
Population Subgroup Percentile Percent
(mg/kg bwt/ Acute RfD
day)
------------------------------------------------------------------------
U.S. Population (48 states)................... 0.051 12%
Infants (< 1 yr).............................. 0.067 16%
Nursing Infants (<1 yr)....................... 0.096 23%
Non-nursing Infants (<1 yr)................... 0.059 14%
Children (1-6 yrs)............................ 0.086 20%
Children (7 - 12 yrs)......................... 0.058 14%
------------------------------------------------------------------------
ii. Chronic exposure and risk. The endpoint selected for chronic
risk assessment is decreased body weight gains in females and increased
thyroid lesions observed in males at 7.6 mg/kg/day in a combined
chronic toxicity/carcinogenicity study in rats. The NOAEL was 5.7 mg/
kg/day. In conducting this chronic dietary (food) risk assessment, EPA
used: (1) tolerance level residues for legumes, strawberries, and all
other commodities with pending, published, permanent or time-limited
imidacloprid tolerances; and, (2) percent crop-treated (%CT)
information on some of these crops. Thus, this risk assessment should
be viewed as partially refined. Further refinement using anticipated
residue values and additional %CT information would result in a lower
estimate of chronic dietary exposure. As discussed above, the FQPA UF
of 3X must also be utilized, resulting in an acceptable dietary
exposure level not to exceed 33.3% of the chronic RfD for all
population subgroups. The Novigen DEEM system was used for this chronic
dietary exposure analysis.
The subgroups listed below are: (1) the U.S. Population (48
states); (2) those for infants and children; and, (3) the other
subgroups (adult) for which the percentage of the RfD occupied is
greater than that occupied by the subgroup U.S. Population (48 states).
The results are summarized below.
------------------------------------------------------------------------
Exposure
Population Subgroup (mg/kg bwt/ %Chronic
day) RfD
------------------------------------------------------------------------
U.S. Population (48 states)................... 0.0037 6.6%
All Infants (< 1 yr).......................... 0.0053 9.3%
Nursing Infants (<1 yr)....................... 0.0017 3.0%
Non-nursing Infants (<1 yr)................... 0.0068 12%
Children (1-6 yrs)............................ 0.0086 1.5%
Children (7-12 yrs)........................... 0.0054 9.5%
U.S. Population (Autumn & Winter)............. 0.0038 6.7%
Non-Hispanic Black............................ 0.0038 6.7%
Females (13+ / Nursing)....................... 0.0038 6.7%
Non-Hispanic Others........................... 0.0041 7.2%
------------------------------------------------------------------------
2. From drinking water. There is no established Maximum Contaminant
Level or Health Advisory Levels for imidacloprid in drinking water. To
date, there are no validated modeling approaches for reliably
predicting pesticide levels in drinking water. The Agency uses models
designed for use for ecological assessment, which are not ideal tools
for use in drinking water risk assessment, as they could overestimate
actual drinking water concentrations. Thus, these models are considered
a coarse screening tool for sorting out pesticides for which it is
highly unlikely that drinking water concentrations would ever exceed
human health levels of concern. For surface water, the Agency 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 which are used to produce estimates of pesticide
concentrations in a farm pond. For ground water the Agency used 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.
In the absence of monitoring data for pesticides, drinking water
levels of comparison (DWLOCs) are calculated
[[Page 3040]]
and used as a point of comparison against the model estimates of a
pesticide's concentration in water. DWLOCs are theoretical upper limits
on a pesticide's concentration in drinking water in light of total
aggregate exposure to a pesticide in food, drinking water, and
residential uses. A DWLOC will vary depending on the toxic endpoint,
with drinking water consumption, and body weights. Different
populations will have different DWLOCs. DWLOCs are used in the risk
assessment process as a surrogate measure of potential exposure
associated with pesticide exposure through drinking water. DWLOC values
are not regulatory standards for drinking water. Since DWLOCs address
total aggregate exposure to imidacloprid they are further discussed in
the aggregate risk sections below.
i. Acute exposure. EPA used estimated concentrations of
imidacloprid in surface and ground water for acute exposure analysis of
4.1 and 1.1 milligram/Liter (<greek-m>g/L) parts per billion (ppb),
respectively. These estimated concentrations of imidacloprid in surface
and ground water were based upon an application rate of 0.5 lbs active
ingredient/ Acre/year (ai/A/year). For purposes of risk assessment, the
estimated maximum concentration of 4.1 ppb was used. The calculated
acute DWLOCs ranged from 440 ppb for Nursing Infants <1 yr. old, to
3,100 ppb for the U.S. population - Males.
ii. Short-term exposure. For purposes of risk assessment, the
estimated maximum chronic exposure of imidacloprid from surface and
ground waters of 1.1 <greek-m>g/L is used for comparison to the back-
calculated human health DWLOCs for the short-term endpoint. The DWLOC
for short-term exposure for the population subgroup of concern,
Children 1 - 6 yrs. old was calculated to be 600 ppb.
iii. Chronic exposure. EPA used estimated concentrations of
imidacloprid in surface and ground water for chronic exposure analysis
of 0.1 and 1.1 <greek-m>g/L (ppb), respectively. These estimated
concentrations of imidacloprid in surface and ground water are based
upon an application rate of 0.5 lbs ai/A/year. The calculated chronic
DWLOCs ranged from 100 ppb for Children 1 - 6 yrs. old, to 540 ppb for
the U.S. population - Males.
iv. Conclusions concerning residues in drinking water. The
estimated concentrations of imidacloprid in surface and ground water
are considerably less than the Agency's DWLOCs for imidacloprid in
drinking water as a contribution to acute, short-term, and chronic
aggregate exposure. Therefore, taking into account the present uses,
including those under emergency exemptions, EPA concludes with
reasonable certainty that residues of imidacloprid in drinking water
would not result in an unacceptable estimate of acute, short-term, or
chronic aggregate human health risk at this time.
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, bathrooms,
household or domestic dwellings (indoor/outdoor), cats/dogs, and wood
protection treatment to buildings. Available data do not demonstrate
that imidacloprid has either dermal or inhalation toxicity potential,
therefore, occupational/residential risk assessments are not required.
Since 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, oral exposure due to the
registered residential uses may result, in particular for Children (1-6
years old). Post-application exposure scenarios for children include:
incidental non-dietary ingestion of residues on lawn from hand-to-mouth
transfer; ingestion of pesticide-treated turfgrass; incidental
ingestion of soil from treated gardens; and incidental ingestion of
pesticide residues on pets from hand-to-mouth transfer. These exposures
are considered to be short-term oral exposures, and thus a residential
short-term risk assessment via the oral route is required.
Incidental ingestion of pesticide residues on pets from hand-to
mouth transfer may occur during the same period as the exposures from
the turf and home garden uses. However, children's exposures from pet
and turf uses are not expected to both occur at the high-end level.
Therefore, these exposures were considered in separate estimates of
risk. For Children (1 - 6 years), the residential exposure from the
home garden and turf uses was estimated to be 0.072 mg/kg bwt/day and
the residential exposure from the pet use was estimated to be 0.058 mg/
kg bwt/day.
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.'' An explanation of the current Agency
approach to assessment of pesticides with a common mechanism of
toxicity may be found in the Final Rule in Bifenthrin Pesticide
Tolerances (Federal Register, November 26, 1997, 62 FR 62961-62970).
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. Imidacloprid is the sole member to date
of the new chloronicotinyl class of pesticides.
C. Aggregate Risks and Determination of Safety for U.S. Population
1. Acute risk. Acute dietary risk was estimated using the
conservative TMRC assumptions, as explained above. There was no
refinement using anticipated residue values and percent crop-treated
information in conjunction with Monte Carlo analysis which would result
in much lower estimates of acute dietary exposure. For the most highly
exposed subgroup, (Nursing Infants <1 Year) dietary esposure was
estimated to utilize 23% of the acute RfD. Since an additional 3-fold
uncertainty factor is used, in accordance with FQPA requirements, for
imidacloprid an acceptable acute dietary exposure (food plus water) is
33.3% or less of the acute RfD.
For the purposes of this risk assessment, the estimated maximum
concentration for imidacloprid in surface and ground waters of 4.1
<greek-m>g/L is used for comparison to the human health DWLOCs for the
acute endpoint. Despite the potential for exposure to imidacloprid in
drinking water, after calculating DWLOCs and comparing them to these
conservative model estimates of concentrations of imidacloprid for
surface and ground water, EPA does not expect the aggregate exposure to
exceed 33.3% of the acute RfD. Under current guidelines, non-dietary
uses of imidacloprid do not constitute an acute exposure scenario.
Therefore, EPA concludes that there is a reasonable certainty that no
harm will
[[Page 3041]]
result to infants, children, or adults from acute aggregate (food and
water) exposure to imidacloprid residues.
Dermal and inhalation exposure endpoints were not selected due to
the demonstrated absence of toxicity; thus, there is no residential
component for assessing chronic aggregate exposure and risk.
The refined assumptions described above were used, and thus this
risk assessment should be viewed as partially refined. Further
refinement using anticipated residue values and additional %CT
information would result in a lower estimate of chronic dietary
exposure. EPA has estimated that the chronic exposure to imidacloprid
from food for the most highly exposed adult population subgroup (Non-
Hispanic Other Than Black or White) will utilize 7.2% of the Chronic
RfD, and for the most highly exposed population subgroup that includes
children (Children, 1-6 years old), dietary exposure will utilize 15%
of the Chronic RfD, as shown previously. For imidacloprid, it was
determined that an acceptable chronic dietary exposure (food plus
water) of 33.3% or less of the Chronic RfD is needed to protect the
safety of all population subgroups (due to the FQPA 3-fold uncertainty
factor).
For purposes of chronic risk assessment, the estimated maximum
concentration for imidacloprid in surface and ground waters (which is
1.1 <greek-m>g/L) is used for comparison to the human health drinking
water levels of comparison (DWLOCs) for the chronic (non-cancer)
endpoint. Despite the potential for exposure to imidacloprid in
drinking water, after calculating DWLOCs and comparing them to these
conservative model estimates of concentrations of imidacloprid for
surface and ground water, EPA does not expect the aggregate exposure to
exceed 33.3% of the chronic RfD. Therefore, EPA concludes that there is
a reasonable certainty that no harm will result to infants, children,
or adults from chronic aggregate (food and water) exposure to
imidacloprid residues.
2. Short- and intermediate-term risk. Short- and intermediate-term
aggregate exposure takes into account chronic dietary food and water
(considered to be a background exposure level) plus indoor and outdoor
residential exposure. Dermal and inhalation short- and intermediate
term risk assessments are not required for imidacloprid as dermal and
inhalation exposure endpoints were not identified due to the
demonstrated absence of toxicity. Short- and intermediate-term oral
exposure are not expected for adult population subgroups. Thus, this
risk assessment is not required.
Since imidacloprid is registered for use on turf, home gardens and
pets. EPA has identified potential short-term oral exposures to
children for these uses. These exposures were considered in separate
estimates of risk. These risk estimates are discussed below in the
section on aggregate risks and determination of safety for infants and
children.
3. 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.
4. Determination of safety. Based on these risk assessments, EPA
concludes that there is reasonable certainty that no harm will result
from aggregate exposure to imidacloprid residues.
D. 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. 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 database 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 MOE
and 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.
ii. Developmental toxicity studies. In the rat developmental study,
the maternal (systemic) NOAEL was 30 mg/kg/day, based on decreased
weight gain at the LOEL of 100 mg/kg/day. The developmental (fetal)
NOAEL was 30 mg/kg/day based on increased wavy ribs at the LOEL of 100
mg/kg/day. In the rabbit developmental study, the maternal (systemic)
NOAEL was 24 mg/kg/day, based on decreased body weight, increased
resorptions and abortions, and death at the LOEL of 72 mg/kg/day. The
developmental (fetal) NOAEL was 24 mg/kg/day, based on decreased body
weight and increased skeletal anomalies at the LOEL of 72 mg/kg/day.
iii. Reproductive toxicity study. 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/day for males and 0, 8.0, 20.5, or 57.4 mg/kg/day for
females). For parental/systemic/reproductive toxicity, the NOAEL was
250 ppm (18.3 mg/kg/day) and the LOEL was 750 ppm (52 mg/kg/day), based
on decreases in body weight in both sexes in both generations.
iv. Pre- and post-natal sensitivity. 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 data did not identify any increased
sensitivity of rats to in utero or postnatal exposure. Parental NOAELs
were lower or equivalent to developmental or offspring NOAELs. The
developmental toxicity studies are designed to evaluate adverse effects
on the developing organism resulting from maternal pesticide exposure
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.
v. Conclusion. 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
[[Page 3042]]
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 for 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, the UF
for FQPA is being applied for all population subgroups, and for both
acute and chronic risk. Therefore, for the purposes of this risk
assessment, dietary exposure must not be above 33.3% of the RfD, to
make the finding of reasonable certainty of no harm.
2. Acute risk. More detail on the acute risk assessments are given
above. EPA used the conservative exposure assumptions described above,
and estimated acute exposure to imidacloprid from food will utilize 23%
of the acute RfD for the most highly exposed population subgroup that
includes children (Non-nursing Infants <1 yr. old). All other
population subgroups have acute risk estimates below this level. It was
determined that an acceptable acute dietary exposure (food plus water)
for imidacloprid is 33.3% or less of the acute RfD, and the estimated
exposures for all population subgroups at the 99th percentile are less
than this level. Despite potential for exposure to imidacloprid via
drinking water, EPA does not expect the aggregate exposure to exceed
33.3% of the acute RfD. Under current EPA guidelines, the registered
non-dietary uses of imidacloprid do not constitute an acute exposure
scenario. Therefore, EPA concludes that there is reasonable certainty
that no harm will result to infants and children from acute aggregate
exposure to imidacloprid residues.
3. Chronic risk. Using the conservative exposure assumptions
described above, EPA has concluded that aggregate exposure to
imidacloprid from food will utilize 15% of the RfD for the most highly
exposed population subgroup, Children (1-6 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.
However, as discussed previously, a 3X UF in accordance with FQPA is
also required. Thus, for the purposes of this risk assessment, dietary
exposure must not be above 33.3% of the RfD, to make the finding of
reasonable certainty of no harm. Despite the potential for exposure to
imidacloprid in drinking water and from non-dietary, non-occupational
exposure, EPA does not expect the aggregate exposure to exceed 33.3% of
the RfD. EPA concludes that there is a reasonable certainty that no
harm will result to infants and children from aggregate exposure to
imidacloprid residues.
4. Short- or intermediate-term risk. Dermal and inhalation short-
and intermediate term risk assessments are not required for
imidacloprid as dermal and inhalation exposure endpoints were not
identified due to the demonstrated absence of toxicity. Short- and
intermediate-term oral exposures are not expected for adult population
subgroups. Thus, this risk assessment is not required.
Since imidacloprid is registered for use on turf, home gardens and
pets. EPA has identified potential short-term oral exposures to
children for these uses. These exposures could occur through the
following routes: incidental ingestion of residues on lawns from hand-
to-mouth transfer; ingestion of pesticide-treated turfgrass; incidental
ingestion of soil from treated gardens; and, incidental ingestion of
pesticide residues on pets from hand-to-mouth transfer. These exposures
are considered to be short-term oral exposures. Incidental ingestion of
pesticide residues on pets from hand-to-mouth transfer may occur during
the same period as the exposures from the turf and home garden uses.
However, it is extremely unlikely that children's exposures from pet
and turf/garden uses would both occur at the high-end level. Therefore,
these exposures are considered in two separate estimates of risk.
A short-term oral endpoint was not identified for imidacloprid.
According to current Agency 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) plus residential exposure. The short-term risk
estimates for the population subgroup (Children, 1-6 yrs. old) is
summarized below. This subgroup was chosen because it has the highest
chronic food exposure and because toddlers have the highest exposure
from the residential uses.
The table below aggregates the dietary exposure (food only) and
residential exposures from the two different routes (hand-to-mouth from
turf and home garden use; and hand-to-mouth from pet use) for the
population subgroup Children 1-6 yrs. old.
Imidacloprid: Short-Term Aggregate Exposure and Risk for Children (1-6
Yrs. Old)
------------------------------------------------------------------------
Chronic Food Residential Total Margin of
Exposure Exposure (mg/ Exposure (mg/ Exposure (mg/ Exposure
Scenario kg bwt/day) kg bwt/day) kg bwt/day) (MOE)
------------------------------------------------------------------------
Turf & Garden
Use......... 0.0086 0.072 0.081 520
Pet Use...... 0.0086 0.058 0.067 630
------------------------------------------------------------------------
As the table indicates, the total MOEs are 520 and 630, for turf/
garden and pet uses, respectively, both of which are higher than 300,
the determined acceptable MOE for imidacloprid. Additionally, 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 (Children, 1 - 6 Yrs. Old) from
home garden, turf, and pet uses of imidacloprid does not exceed EPA's
level of concern.
[[Page 3043]]
IV. Other Considerations
A. Metabolism In Plants and Animals
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 .
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 Pesticide
Analytical Manual II (PAM II). In the interim, these methods are
available from Calvin Furlow, EPA, OPP, IRSD, PIRIB.
C. Magnitude of Residues
Residues of imidacloprid and its metabolites containing the 6-
chloropyridinyl moiety, all expressed as parent, are not expected to
exceed 0.1 ppm in/on strawberries, and 1.0 ppm in/on legume vegetables.
D. International Residue Limits
There are no Codex, Canadian, or Mexican maximum residue limits
(MRLs) for imidacloprid on legumes or strawberries. International
compatibility is thus not an issue.
E. Rotational Crop Restrictions
EPA previously concluded that field crop rotational studies with
three crop groups (small grains, root crops, and leafy vegetables)
supported a 12-month plant-back restriction. However, EPA recently
recommended in favor of granting tolerances for inadvertent residues of
imidacloprid in/on the following crop groups: cereal grains, forage,
fodder, and straw of cereal grains, legume vegetables and the foliage
of legume vegetables; and on sweet corn, soybeans, and safflower. EPA
recommended a 30-day plant back interval be observed fore these crops.
Therefore, the following rotation restriction is adequate for this
section 18 use: Any crops may be planted back 12 months following
imidacloprid applications, except for the following: crops having
imidacloprid tolerances, sweet corn, soybeans, and safflower; and the
commodities of the crop groups Cereal grains and Legume vegetables.
These aforementioned crops may be rotated 30-days after the last
imidacloprid treatment; except for crops with imidacloprid tolerances,
which may be rotated at any time.
V. Conclusion
Therefore, the time-limited tolerances are established for residues
of imidacloprid in/on legume vegetables at 1.0 ppm, and strawberry at
0.1 ppm.
VI. 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 March 22, 1999, 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(i). If a hearing is requested, 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 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.
VII. Public Record and Electronic Submissions
EPA has established a record for this rulemaking under docket
control number [OPP-300771] (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 Room 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 Highway, Arlington, VA.
Electronic comments may be sent directly to EPA at:
opp-docket@epamail.epa.gov.
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.
VIII. Regulatory Assessment Requirements
A. Certain Acts and Executive Orders
This final rule establishes time-limited tolerances 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).
[[Page 3044]]
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 prior consultation as
specified by Executive Order 12875, entitled Enhancing the
Intergovernmental Partnership (58 FR 58093, October 28, 1993), or
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 these tolerances and exemptions that are
established under FFDCA section 408 (l)(6), such as the tolerances 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 the
Intergovernmental Partnership (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 to 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 officials and other representatives of Indian tribal
governments ``to provide meaningful and timely input in the development
of regulatory policies on matters that 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.
IX. 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: December 23, 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.
2. In Sec. 180.472, by alphabetically adding the following
commodities to the table in paragraph (b) to read as follows:
Sec. 180.472 Imidacloprid; tolerances for residues.
* * * * *
(b) * * *
------------------------------------------------------------------------
Expiration/
Commodity Parts per million Revocation Date
------------------------------------------------------------------------
* * * * *
Legume Vegetables............... 0.1 6/30/00
Strawberry...................... 1.0 6/30/00
* * * * *
------------------------------------------------------------------------
* * * * *
[FR Doc. 99-1253 Filed 1-19-99; 8:45 am]
BILLING CODE 6560-50-F