[Federal Register Volume 64, Number 199 (Friday, October 15, 1999)]
[Notices]
[Pages 55914-55921]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-26971]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-891; FRL-6099-6]
Notice of Filing Pesticide Petitions To Establish a Tolerance for
Certain Pesticide Chemicals in or on Food
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
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SUMMARY: This notice announces the initial filing of pesticide
petitions proposing the establishment of regulations for residues of
certain pesticide chemicals in or on various food commodities.
DATES: Comments, identified by docket control number PF-891, must be
received on or before November 15, 1999.
ADDRESSES: Comments may be submitted by mail, electronically, or in
person. Please follow the detailed instructions for each method as
provided in Unit I.C. of the ``SUPPLEMENTARY INFORMATION'' section. To
ensure proper receipt by EPA, it is imperative that you identify docket
control number PF-891 in the subject line on the first page of your
response.
FOR FURTHER INFORMATION CONTACT: The product manager listed in the
table below:
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Office location/telephone
Product Manager number/e-mail address Address Petition number(s)
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Ann Sibold......................... Rm. 212, CM #2, 703-305- 1921 Jefferson Davis PP 6H5743
6502, e-mail: Hwy, Arlington, VA
[email protected]
.
William Sproat..................... Rm. 6044, CM #2, 703-308- Do. PP 9F6043
8587, e-mail:
[email protected]
.gov.
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SUPPLEMENTARY INFORMATION:
I. General Information
A. Does This Action Apply to Me?
You may be affected by this action if you are an agricultural
producer, food manufacturer or pesticide manufacturer. Potentially
affected categories and entities may include, but are not limited to:
------------------------------------------------------------------------
Examples of
Categories NAICS potentially
affected entities
------------------------------------------------------------------------
Industry 111 Crop production
112 Animal production
311 Food manufacturing
32532 Pesticide
manufacturing
------------------------------------------------------------------------
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in the table could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether or not this action might apply to certain entities. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed in the ``FOR FURTHER INFORMATION
CONTACT'' section.
B. How Can I Get Additional Information, Including Copies of This
Document and Other Related Documents?
1. Electronically. You may obtain electronic copies of this
document, and certain other related documents that might be available
electronically, from the EPA Internet Home Page at http://www.epa.gov/.
To access this document, on the Home Page select ``Laws and
Regulations'' and then look up the entry for this document under the
``Federal Register--Environmental Documents.'' You can also go directly
to the Federal Register listings at http://www.epa.gov/fedrgstr/.
2. In person. The Agency has established an official record for
this action under docket control number PF-891. The official record
consists of the documents specifically referenced in this action, any
public comments received during an applicable comment period, and other
information related to this action, including any information claimed
as confidential business information (CBI). This official record
includes the documents that are physically located in the docket, as
well as the documents that are referenced in those documents. The
public version of the official record does not include any information
claimed as CBI. The public version of the official record, which
includes printed, paper versions of any electronic comments submitted
during an applicable comment period, is available for inspection in the
Public Information and Records Integrity Branch (PIRIB), Rm. 119,
Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA, from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
C. How and to Whom Do I Submit Comments?
You may submit comments through the mail, in person, or
electronically. To ensure proper receipt by EPA, it is imperative that
you identify docket control number PF-891 in the subject line on the
first page of your response.
1. By mail. Submit your comments to: Public Information and Records
Integrity Branch (PIRIB), Information Resources and Services Division
(7502C), Office of Pesticide Programs, Environmental Protection Agency,
401 M St., SW., Washington, DC 20460.
2. In person or by courier. Deliver your comments to: Public
Information and Records Integrity Branch (PIRIB), Information Resources
and Services Division (7502C), Office of Pesticide Programs (OPP),
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921
Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
3. Electronically. You may submit your comments electronically by
E-mail to: ``[email protected] ,'' or you can submit a computer disk
as described above. Do not submit any information electronically that
you consider to be CBI. Avoid the use of special characters
[[Page 55915]]
and any form of encryption. Electronic submissions will be accepted in
Wordperfect 5.1/6.1 or ASCII file format. All comments in electronic
form must be identified by docket control number PF-891. Electronic
comments may also be filed online at many Federal Depository Libraries.
D. How Should I Handle CBI That I Want To Submit to the Agency?
Do not submit any information electronically that you consider to
be CBI. You may claim information that you submit to EPA in response to
this document as CBI by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
with procedures set forth in 40 CFR part 2. In addition to one complete
version of the comment that includes any information claimed as CBI, a
copy of the comment that does not contain the information claimed as
CBI must be submitted for inclusion in the public version of the
official record. Information not marked confidential will be included
in the public version of the official record without prior notice. If
you have any questions about CBI or the procedures for claiming CBI,
please consult the person identified in the ``FOR FURTHER INFORMATION
CONTACT'' section.
E. What Should I Consider as I Prepare My Comments for EPA?
You may find the following suggestions helpful for preparing your
comments:
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide copies of any technical information and/or data you
used that support your views.
4. If you estimate potential burden or costs, explain how you
arrived at the estimate that you provide.
5. Provide specific examples to illustrate your concerns.
6. Make sure to submit your comments by the deadline in this
notice.
7. To ensure proper receipt by EPA, be sure to identify the docket
control number assigned to this action in the subject line on the first
page of your response. You may also provide the name, date, and Federal
Register citation.
II. What Action Is the Agency Taking?
EPA has received pesticide petitions as follows proposing the
establishment and/or amendment of regulations for residues of certain
pesticide chemicals in or on various food commodities under section 408
of the Federal Food, Drug, and Comestic Act (FFDCA), 21 U.S.C. 346a.
EPA has determined that these petitions contain data or information
regarding the elements set forth in section 408(d)(2); however, EPA has
not fully evaluated the sufficiency of the submitted data at this time
or whether the data supports granting of the petition. Additional data
may be needed before EPA rules on the petition.
List of Subjects
Environmental protection, Agricultural commodities, Feed additives,
Food additives, Pesticides and pests, Reporting and recordkeeping
requirements.
Dated: October 7, 1999.
James Jones,
Director, Registration Division, Office of Pesticide Programs.
Summaries of Petitions
The petitioner summaries of the pesticide petitions are printed
below as required by section 408(d)(3) of the FFDCA. The summaries of
the petitions were prepared by the petitioners and represent the views
of the petitioners. EPA is publishing the petition summaries verbatim
without editing them in any way. The petition summary announces the
availability of a description of the analytical methods available to
EPA for the detection and measurement of the pesticide chemical
residues or an explanation of why no such method is needed.
1. AgrEvo Environmental Health
PP 6H5743
EPA has received a pesticide petition (PP 6H5743) from AgrEvo
Environmental Health, 95 Chestnut Ridge Road, Montvale, NJ 07645
proposing, pursuant to section 408(d) of the Federal Food, Drug, and
Cosmetic Act, 21 U.S.C. 346a(d), to amend 40 CFR part 180 by
establishing a tolerance for residues of esbiothrin and S-bioallethrin
in or on food/feed items as a result of applications in food/feed
handling establishments at 1.0 parts per million (ppm). EPA has
determined that the petition contains data or information regarding the
elements set forth in section 408(d)(2) of the FFDCA; however, EPA has
not fully evaluated the sufficiency of the submitted data at this time
or whether the data supports granting of the petition. Additional data
may be needed before EPA rules on the petition.
A. Residue Chemistry
1. Plant metabolism. The nature of the residues of esbiothrin and
S-bioallethrin in plants relevant to the establishment of a food/feed
additive tolerance is adequately understood. Metabolism data have been
generated on tomatoes, wheat and lettuce as well as samples of these
stored commodities. All degradates found from the metabolism samples
had structures consistent with photoproducts of allethrin. Only very
minor amounts of cleavage products were found, indicating that
metabolic or abiotic cleavage was not occurring to any great extent. In
view of the known rapid photodegradation of allethrin and related
compounds, it is most likely that these products arose from photolysis,
rather than metabolism. No metabolites of toxicological concern were
identified. Therefore, the only residue of concern is allethrin.
2. Analytical method. Analytical methods for determining residues
of allethrin in a variety of food commodities have been developed and
submitted to the Agency. These methods use gas chromatography (GC) with
quantitation by an electron capture detector (ECD) for determination of
total allethrin residues. These methods have been validated and are
appropriate for the determination of allethrin residues in a variety of
food commodities after application in food/feed handling
establishments.
3. Magnitude of residues. The magnitude of the residue study
demonstrated that residues of esbiothrin and S-bioallethrin are not
expected to exceed the proposed tolerance level of 1.0 ppm as a result
of the use of these compounds in food/feed handling establishments.
B. Toxicological Profile
1. Acute toxicity--i. S-bioallethrin. The acute rat oral
LD50 of S-bioallethrin was 574 milligrams/kilograms (mg/kg)
(males) and 413 mg/kg (females) when administered in PEG 200 and 607
mg/kg (males) and 497 mg/kg (females) when administered in corn oil.
The acute rabbit dermal LD50 was greater than 2,000 mg/kg.
The acute rat inhalation LC50 was 1.26 milligrams per liter
(mg/L). S-bioallethrin was found to be slightly irritating to rabbit
eyes, non-irritating to rabbit skin, and did not elicit a sensitizing
response in guinea pigs.
ii. Esbiothrin. The acute oral LD50 of esbiothrin in
rats was 432.3 mg/kg (males) and 378 mg/kg (females). The acute dermal
LD50 in rabbits was greater than 2,000 mg/kg. The acute
inhalation LC50 in rats was 2.59 mg/L. Esbiothrin
[[Page 55916]]
was found to be non-irritating to rabbit eyes, slightly irritating to
rabbit skin, and did not elicit a sensitizing response in guinea pigs.
2. Genotoxicity. No indication of genotoxicity was noted in a
battery of in vivo and in vitro studies conducted with either S-
bioallethrin or esbiothrin.
3. Reproductive and developmental toxicity--i. S-bioallethrin. In a
rat developmental toxicity study, animals were administered S-
bioallethrin at 0, 5, 20, and 80 mg/kg/day during gestation days 6-15.
Maternal mortality, tremors, piloerection and body weight (bwt) changes
were observed. No evidence of developmental toxicity was observed. The
maternal no observed adverse effect levels (NOAEL) was 20 mg/kg/day.
The developmental NOAEL was 80 mg/kg/day.
In a rabbit developmental toxicity study, animals were administered
S-bioallethrin at 0, 5, 50, or 200 mg/kg/day during gestation days 6-
19. Tremors and reduced bwts and food consumption were reported. The
maternal NOAEL was 50 mg/kg/day. Some evidence of slight developmental
delay and an associated increased incidence of extra ribs and vertebrae
were noted at the 200 mg/kg/day level. However these findings were only
observed at the maternally toxic dose. The developmental NOAEL was 50
mg/kg/day.
ii. Esbiothrin. In a developmental toxicity study, rats were
administered 0, 5, 25, and 125 mg/kg/day esbiothrin during gestation
days 6-15. The maternal NOAEL was 25 mg/kg/day based on mortality and
excess salivation, urine staining of the abdominal fur, tremors, body
jerks and hypersensitivity to sound. There were no indications of
developmental toxicity. The developmental NOAEL was 125 mg/kg/day.
In a rabbit developmental toxicity study, animals were administered
esbiothrin at 0, 30, 100, and 300 mg/kg/day during gestation days 6-18.
The maternal NOAEL was 100 mg/kg/day based on deaths, tremors,
decreased motor activity, and ataxia. There were no indications of
developmental toxicity. The developmental NOAEL was 300 mg/kg/day.
In a 2-generation reproduction study, esbiothrin was administered
to rats at dietary concentrations of 0, 70, 200, 600, and 1,800 ppm.
Decreased body weights (bwts) and mortality were observed in F1
parental animals. Slight decreases in pup viability and pup weights
were observed only in the F1 generation and were confined to four
litters in the high dose group. The reproductive NOAEL was 600 ppm or
50.4 mg/kg/day.
4. Subchronic toxicity--i. S-bioallethrin. A 28-day dermal toxicity
study was conducted with S-bioallethrin applied to the backs of rats at
0, 10, 100, or 1,000 mg/kg/day for 6 hours/exposure 5 days/week for a
total of 28 exposures. There were no treatment-related effects
observed. The NOAEL was 1,000 mg/kg/day.
A 28-day rat inhalation study was conducted with S-bioallethrin at
analytical concentrations of 0 (air only), 0.0051, 0.025, and 0.073 mg/
L. Animals were exposed for 6 hours/day, 5 days/week for a total of 4
weeks. Intermittent limb tremors, walking on ``tip toes,'' hunched
posture, aggressive behavior and vocalizing when handled were observed
at 0.025 and 0.073 mg/L. The NOAEL was 0.0051 mg/L.
In a 90-day feeding study, rats were administered S-bioallethrin at
dietary concentrations of 0, 250, 500, 2,000, and 8,000 ppm. Reduced
bwt gain, food and water consumption, and increased absolute and
relative liver and thyroid weights were observed at 2,000 ppm and
higher. Various microscopic findings were reported for liver, kidneys
and the thyroid. The NOAEL was 250 ppm or 18.5 mg/kg/day.
In a 90-day feeding study, beagle dogs were administered S-
bioallethrin at dietary concentrations of 0, 400, 1,000, and 2,250 ppm.
Decreased bwt gains, muscle tremors, wasted body condition, and
intermittent incidences of decreased activity, hunched posture,
diarrhea, and increased absolute and relative liver weights were
observed. Histopathologic examination of the liver revealed
centrilobular hepatocyte enlargement. The NOAEL was 1,000 ppm (38.54
mg/kg/day).
ii. Esbiothrin. In a 21-day dermal toxicity study, rabbits were
exposed to 0, 40, 200 and 1,000 mg/kg esbiothrin for 6 hours/day for 5
days/week for 3 weeks. There were no treatment-related systemic
effects. Dermal effects were noted at all dose levels. The NOAEL for
systemic toxicity was 1,000 mg/kg/day highest dose tested (HDT).
5. Chronic toxicity. In a 2-year toxicity/oncogenicity study, rats
were administered 0, 100, 500, 1,500, or 4,500 ppm esbiothrin in the
diet. Decreased bwt gain, increased liver enzymes and cholesterol
levels, increased liver weights, hepatocellular hypertrophy and hepatic
cell degeneration and necrosis were observed. There was no evidence of
oncogenicity. The NOAEL was 500 ppm (27 mg/kg/day).
A 2-year toxicity/oncogenicity study was conducted with esbiothrin
in mice at dietary concentrations of 0, 50, 250, or 1,250 ppm
esbiothrin. Increased absolute and relative liver weights were
observed. There was no evidence of oncogenicity. The NOAEL was 1,250
ppm (214.3 mg/kg/day).
In a 1-year feeding study, beagle dogs were administered dietary
concentrations of 0, 80, 400, and 2,000 ppm esbiothrin. There were no
toxicologically significant effects observed. The NOAEL for this study
was 2,000 ppm (69.9 mg/kg/day).
6. Animal metabolism. It appears that absorption of the allethrins
is dependent upon the vehicle and route of administration. However,
once absorbed, the allethrins are readily excreted. The dermal
absorption determined from a rat dermal absorption study was
approximately 25% when administered in an aromatic hydrocarbon vehicle.
7. Endocrine disruption. No special studies have been conducted to
investigate the potential of esbiothrin or S-bioallethrin to induce
estrogenic or other endocrine effects. However, the standard battery of
required toxicity studies has been completed. The studies include an
evaluation of the potential effects on reproduction and development and
an evaluation of the pathology of the endocrine organs following
repeated or long-term exposure. These studies are generally considered
to be sufficient to detect any endocrine effects, yet no such effects
were detected. Thus, the potential for esbiothrin or S-bioallethrin to
produce any significant endocrine effects is considered to be minimal.
C. Aggregate Exposure
Esbiothrin and S-bioallethrin are broad-spectrum insecticides used
to control various pests in domestic indoor and outdoor areas
(including use on pets), commercial and industrial food use areas and
on ornamental plants. Thus, aggregate non-occupational exposure would
include exposures resulting from non-food uses in addition to
consumption of potential residues in food and water.
Both mixtures possess similar qualitative toxicologic profiles, but
the overall weight of evidence indicates that the d-trans of d isomer
is the most toxicologically significant isomer in these mixtures.
Consequently, after converting into S-bioallethrin equivalents from
esbiothrin data, or vice versa, based on the relative proportions of d-
trans of d, the toxicity data for these mixtures can be used
interchangeably.
1. Dietary exposure--Food. Since there are no agricultural uses
with these active ingredients, an acute dietary exposure was not
evaluated. According to EPA guidelines, food handling establishment
uses should only be
[[Page 55917]]
evaluated for chronic dietary exposure. Potential chronic dietary
exposures from food commodities under the proposed food and feed
additive tolerance for esbiothrin and S-bioallethrin were estimated
using the Exposure 1 software system (TAS, Inc.) and the 1977-78 USDA
consumption data. Dietary risk assessment was conducted in a tiered
approach whereby three scenarios were evaluated. The first scenario
assumed 100% of all food and feed handling establishments (FHE) are
treated with S-bioallethrin or esbiothrin and that all residues from
these treatments are at the proposed tolerance level (1 ppm). The
second scenario assumes that 100% of the FHE are treated and all
residues are at the proposed tolerance level except where actual
residue data are available. The third scenario assumes that, more
realistically, only 25% of the FHE are treated and all residues are at
the proposed tolerance level except for where actual residue data
exist.
2. Drinking water. Exposure via drinking water is expected to be
negligible since esbiothrin and S-bioallethrin are neither persistent
in the environment nor likely to leach. As is characteristic of
pyrethroids, the allethrins bind strongly to soil and will not be
leached out by water. Further, this pyrethroid is rapidly degraded
under environmental conditions (in soil, water and in the presence of
sunlight). The half-life of esbiothrin and S-bioallethrin is
approximately 7-15 minutes in sunlight and no more than 2 hours in
total darkness. Due to these properties, no residues in drinking water
are expected to be present.
3. Non-dietary exposure. As noted above, esbiothrin and S-
bioallethrin are broad-spectrum insecticides developed for use in non-
agricultural applications including indoor foggers, insect mats and
coils, household commercial and institutional insect killers; food and
feed handling applications, commercial non- food/feed sites, pet
applications and greenhouse/ornamental applications. To evaluate non-
dietary exposure, the ``flea infestation control,'' scenario was chosen
to represent a plausible but worst-case non-dietary (indoor and
outdoor) non-occupational exposure. This scenario provides a situation
where S-bioallethrin and/or esbiothrin is commonly used and one in
which both can be used concurrently for a multitude of uses, e.g. spot
treatment of infested indoor surfaces such as carpets and rugs,
treatment of pets and treatment of animal housing. This hypothetical
situation provides a very conservative, upper bound estimate of
potential non-dietary exposures. Consequently, if health risks are
acceptable under these conditions, the potential risks associated with
other more likely scenarios would also be acceptable.
Aggregate short-term risk was calculated by combining the risk
calculated for the ``flea infestation'' scenario (non-dietary risk)
with the chronic dietary risk analyses. As indicated previously, S-
bioallethrin and esbiothrin possess similar qualitative toxicity
profiles. Due to their isomeric mixtures, the product toxicity data for
either product can be converted to the other after the appropriate
conversions have been made based on relative proportions of the d-trans
of d isomer content. For risk assessment purposes, S-bioallethrin will
be used to assess the risk of S-bioallethrin and esbiothrin since it
contains a greater proportion of the more toxicologically significant
isomer, d-trans of d. As a result of using the data in this manner, a
conservative, worst-case evaluation can be made.
D. Cumulative Effects
At the present time, there are insufficient data available to allow
AgrEvo to properly evaluate the potential for cumulative effects from
the various pyrethroids now being used, or from any other chemicals
that may have similar mechanisms of toxicity. Furthermore, because of
the need to utilize data from multiple registrants, such an analysis
cannot be conducted by a single registrant. AgrEvo is currently
participating in a joint industry effort to evaluate the potential
aggregate risks from exposure to all pyrethroids but the results from
this evaluation are not yet available.
As an interim measure, AgrEvo has evaluated the potential
cumulative risks associated with exposure to three products in the
allethrin series: bioallethrin, esbiothrin, and S-bioallethrin. These
products contain varying proportions of d-trans chrysanthemate ester of
d- and l-allethrolone (d-trans d and d-trans l). The uses for these
products are very similar except that no food uses are being proposed
for bioallethrin. The use rates for the three products differ based on
relative efficacy which appears to be related to the percentage of the
most active isomer (d-trans d). The risk assessments conducted in
support of this petition were based on the worst-case assumption that
all residues were from S-bioallethrin, the product with the highest
percentage of the most active isomer. Therefore, the potential
cumulative risks associated with a combination of all three of these
products would actually be lower than those presented here.
E. Safety Determination
1. U.S. population. The combined toxicity and residue data base for
esbiothrin and S-bioallethrin is considered to be valid, reliable and
essentially complete. No evidence of oncogenicity has been observed. In
accordance with EPA's ``Toxicology Endpoint Selection Process''
Guidance Document, the toxicology endpoint from the S-bioallethrin
acute neurotoxicity study, 30 mg/kg, was used to evaluate acute non-
dietary risk. According to current EPA policy, residues from Food
Handling Establishment uses are only evaluated for potential chronic
dietary risk. AgrEvo is proposing a RfD of 0.226 mg/kg bwt/day to
evaluate chronic dietary risk for S-bioallethrin and esbiothrin. This
RfD is based on the NOAEL from the esbiothrin rat chronic toxicity/
oncogenicity study with a 100-fold safety factor to account for
interspecies extrapolation and intraspecies variation. The S-
bioallethrin NOAEL served as a worst-case scenario because it contains
the largest amount of d-trans of d isomer by weight.
The potential chronic dietary exposure for the overall U.S.
population under the three scenarios as described in section D utilize
the following portions of the RfD: 10.73% for scenario 1 (100% FHE
treated and all residues at the proposed tolerance level); 5.28% for
the second scenario (100% FHE treated and all residues at proposed
tolerance level except where actual data exist) and 1.32% of the third
scenario (treatment of only 25% of FHE and residues at proposed
tolerance except where actual data exist). There is generally no
concern for chronic exposures below 100% of the RfD since it represents
the level at or below which no appreciable risks to human health is
posed.
Using an upper bound estimate of potential non-dietary exposure
from a worst-case scenario (flea treatment) results in a margin of
exposure (MOE) of approximately 610,000 for adults with S-bioallethrin
and approximately 510,000 for esbiothrin.
Utilizing the scenario of chronic dietary exposure with an upper
bound estimate of potential non-dietary exposure from a worst-case
scenario (flea treatment), the resulting MOE for aggregate exposure to
S-bioallethrin is 9,800 for the adult population and 8,100 for
esbiothrin for the same population group.
There is generally no concern for MOEs greater than 100 or
utilization of less than 100% RfD. Therefore, there is
[[Page 55918]]
reasonable certainty that no harm will result to the U.S. population in
general from aggregate exposure to S-bioallethrin or esbiothrin.
2. Infants and children. Data from developmental toxicity studies
in rats and rabbits and multi-generation reproduction studies in rats
are generally used to assess the potential for increased sensitivity of
infants and children. The developmental toxicity studies are designed
to evaluate adverse effects on the developing organism resulting from
pesticide exposure during prenatal development. Reproduction studies
provide information relating to reproductive and other effects on
adults and offspring from prenatal and postnatal exposure to the
pesticide. None of the studies conducted with S-bioallethrin or
esbiothrin indicated evidence of developmental or reproductive effects
resulting from exposure to either material at non-maternally toxic
doses.
FFDCA section 408 provides that EPA may apply an additional safety
factor for infants and children in the case of threshold effects to
account for prenatal and postnatal toxicity and the completeness of the
data base. Based on the current toxicological data requirements, the
data base relative to prenatal and postnatal effects in children is
complete. No indication of increased susceptibility to younger animals
was noted in the developmental or reproduction studies at non-
maternally toxic doses or in the majority of studies with other
pyrethroids. Therefore, use of the S-bioallethrin acute neurotoxicity
NOAEL of 30 mg/kg for short-term risk, and the proposed RfD of 0.226
mg/kg/day for assessing chronic aggregate risk to infants and children
is appropriate and an additional uncertainty factor is not warranted.
Using the dietary exposure assumptions described above in section
D, the first scenario utilizes 41.98% of RfD for non-nursing infants (<
1-year) and 26.14% of RfD for children 1-6 years. The second scenario
utilizes 11.96% of the RfD for non-nursing infants < 1-year and 11.54%
of RfD for children 1-6 years. The third scenario utilizes 2.96% of RfD
for non-nursing infants < 1-year and 2.88% of the RfD for children 1-6
years. There is generally no concern for chronic exposures below 100%
of the RfD since it represents the level at or below which no
appreciable risks to human health is posed.
Using an upper bound estimate of potential non-dietary exposures
for a worst case scenario (flea infestation) results in a MOE of 2,300
for infants less than 1-year old for S-bioallethrin and 1,900 for
esbiothrin. A MOE of 2,400 for children 1-6 years was noted for S-
bioallethrin and a MOE of 2,000 for esbiothrin.
Utilizing the scenario of chronic dietary exposure with an upper
bound estimate of potential non-dietary exposure from a worst case
scenario (flea infestation), it can be seen that for aggregate exposure
to S-bioallethrin and esbiothrin, the MOE for infants less than 1-year
is 1,500 for S-bioallethrin and 1,200 for esbiothrin. For children 1-6
years, the MOE's are 1,600 for S- bioallethrin and 1,300 for
esbiothrin.
As noted for the U.S. population, these compounds have a very short
half-life in light and in darkness. These products are metabolized
rapidly from the body and based on general practices, are applied not
more than once per month. Based on these properties and use patterns,
real-life exposures would be acute in nature and at much lower levels
than used in this assessment.
There is generally no concern for MOE's greater than 100, or less
than 100% utilization of RfD. Therefore, there is reasonable certainty
that no harm will result to the most sensitive population subgroup,
described as non-nursing infants less than 1-year and children 1-6
years, from aggregate exposure to esbiothrin and S-bioallethrin.
F. International Tolerances
Esbiothrin and S-bioallethrin are broad spectrum insecticides used
throughout the world to control pests of ornamental plants, household,
commercial and industrial areas (indoor and outdoor). There are
currently no maximum residue limits (MRLs) for esbiothrin or S-
bioallethrin.
2. ZENECA Ag Products
PP 9F6043
EPA has received a pesticide petition [9F6043] from ZENECA Ag
Products, 1800 Concord Pike, Wilmington, DE 19850 proposing, pursuant
to section 408(d) of the FFDCA, 21 U.S.C. 346a(d), to amend 40 CFR part
180 by establishing a tolerance for combined residues of pirimicarb 2-
(dimethylamino)-5,6-dimethyl-4-pyrimidinyl dimethylcarbamate (9Cl) and
its two carbamate metabolites: desmethyl pirimicarb and
desmethylformamido pirimicarb, expressed as desmethyl pirimicarb in or
on the raw agricultural commodities (RAC): potatoes and pre-blossom
apples at 0.01 ppm, head lettuce at 0.3 ppm, leaf lettuce at 2.0 ppm,
and endive (curly and escarole) at 2.0 ppm. EPA has determined that the
petition contains data or information regarding the elements set forth
in section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated
the sufficiency of the submitted data at this time or whether the data
supports granting of the petition. Additional data may be needed before
EPA rules on the petition.
A. Residue Chemistry
1. Plant metabolism. Studies of the nature of residues in three
diverse crops, potatoes, apples, and lettuce, have demonstrated that
pirimicarb undergoes very extensive metabolism, with the residues of
concern in primary crops being both pirimicarb and its carbamate
metabolites. Zeneca proposes that combined residues of pirimicarb, 2-
(dimethylamino)-5,6-dimethyl-4-pyrimidinyl dimethylcarbamate (9Cl), and
its two carbamate metabolites (desmethyl pirimicarb and
desmethylformamido pirimicarb) expressed as desmethyl pirimicarb are to
be included in the tolerance.
2. Analytical method. The analytical enforcement method uses Gas
Chromatography (GC) equipped with a thermionic nitrogen specific
detector. Crop samples are macerated with methanol and then filtered.
After filtration, the methanol is evaporated and the samples
resuspended and partitioned with hexane and hydrochloric acid. The
samples are left overnight to allow conversion of the desmethylforamido
pirimicarb metabolite to the desmethyl pirimicarb metabolite. The
hexane layer is discarded and the acidic aqueous layer is further
partitioned with ethyl acetate. Sodium hydroxide is added to the
aqueous layer and pirimicarb and its carbamate metabolites are
extracted with dichloromethane. This method has been validated by an
independent laboratory, with a LOD of 0.01 ppm.
3. Magnitude of residues. Residue trials were conducted on
potatoes, pre-blossom apples, and lettuce in the major crop growing
areas of the United States. Sixteen residue trials were done on
potatoes at the maximum label rate. At time of harvest, there were no
detectable residues of either pirimicarb or its carbamate metabolites
at the LOD of 0.01 ppm. A processing study on potatoes at 5x the
maximum label rate also demonstrated that there are no detectable
residues of pirimicarb or its carbamate metabolites at the LOD of 0.01
ppm on potatoes, potato peel, or any of the processed fractions (flakes
and chips).
Sixteen residue trials were conducted on apples at the pre-blossom
stage, using one application at the maximum label rate. At time of
harvest, there were
[[Page 55919]]
no detectable residues of pirimicarb or its carbamate metabolites at
the LOD of 0.01 ppm. An apple processing study at 5x the maximum label
rate also demonstrated that there were no detectable residues of
pirimicarb or its carbamate metabolites at the LOD of 0.01 ppm on
apples, or any of the processed fractions (pomace, juice).
Six residue trials were completed on head lettuce at the maximum
label rate. Mature lettuce leaves were analyzed for pirimicarb and its
carbamate metabolites. Maximum residues of 0.24 ppm were detected for
the combined residues of pirimicarb and its carbamate metabolites.
Six residue trials were completed on leaf lettuce at the maximum
label rate. Mature lettuce leaves were analyzed for pirimicarb and its
carbamate metabolites. Maximum residues of 1.73 ppm were detected for
the combined residues of pirimicarb and its carbamate metabolites.
ZENECA requests that the Agency also use these leaf lettuce residue
trials as surrogate data for the commodity endive (curly and escarole).
B. Toxicological Profile
1. Acute toxicity. In common with other carbamate insecticides,
pirimicarb induces toxic signs characteristic of cholinesterase
inhibition. These effects are rapidly reversed on the cessation of
treatment and recovery is usually full and complete.
Formulated pirimicarb (PIRIMOR DF) is classed as Category II
toxicity based on the highest hazard for either the technical or
formulated product.
Pirimicarb Toxicity Summary
------------------------------------------------------------------------
Toxicity test Results Toxicity category
------------------------------------------------------------------------
Acute oral rat.................. LD50 152 mg/kg II
(m),142 mg/kg (f)
Acute dermal rat................ LD50 >1,000 mg/kg III
(f)
Acute inhalation rat............ 0.95 mg/L (m); III
0.86 mg/L (f)
Eye irritation rabbit........... Non-irritant IV
Skin irritation rabbit.......... Slight irritant IV
Skin sensitization.............. Moderate May cause allergic
reaction
------------------------------------------------------------------------
Formulated Material (PIRIMOR DF) Toxicity Summary
------------------------------------------------------------------------
Toxicity test Results Toxicity category
------------------------------------------------------------------------
Acute oral rat.................. LD50 87 mg/kg II
Acute dermal rat................ LD50 > 2,000 mg/kg III
Acute inhalation rat............ 1.7 mg/L (f) III
Eye irritation rabbit........... Moderate irritant II
Skin irritation rabbit.......... Slight irritant IV
Skin sensitization.............. Not a sensitizer - -
------------------------------------------------------------------------
2. Genotoxicity. Pirimicarb has been evaluated for genotoxicity and
mutagenicity. Pirimicarb does not induce gene mutation in either
prokaryotic or non-mammalian eukaryotic cells.
3. Reproductive and developmental toxicity. Pirimicarb was not
teratogenic to rats when tested in a study using oral gavage dose
levels of 0, 10, 25, and 75 mg/kg/day. Fetotoxicity in the presence of
maternal toxicity was observed at 75 mg/kg/day, but there were no
effects on mother or fetus at a dose level of 25 mg/kg/day. The overall
NOAELs for fetotoxicity was therefore, 25 mg/kg/day in the rat.
Pirimicarb was not teratogenic in the rabbit when tested in a study
using oral gavage dose levels of 0, 2, 10, or 60 mg/kg/day. Maternal
toxicity was observed at 60 mg/kg/day, but there were no effects on the
fetus at any dose level. There was no evidence of fetotoxicity or
teratogenicity in the rabbit at doses up to and including a maternally
toxic dose of 60 mg/kg/day.
Neither study showed effects on the fetus in the absence of effects
on the mother, and thus there was no evidence of enhanced fetal
susceptibility to pirimicarb.
Pirimicarb showed no evidence of reproductive toxicity to rats in a
2-generation reproductive toxicity study using dose levels of 0, 50,
200, or 750 ppm. There were no effects on reproductive parameters at
750 ppm (88 mg/kg/day), the highest dose tested (HDT).
4. Subchronic toxicity--i. Ninety-day rat feeding. In an number of
repeat dose studies, male and female rats were fed diets containing 0,
175, 250, or 750 ppm of pirimicarb for a period of 56-90 days. There
were no adverse clinical, hematological, or pathological effects. The
only effect was a reduction in body weight gain, which was clearly
evident at 750 ppm in 2 studies, and one study showed slight effects at
250 ppm. The NOAEL for subchronic toxicity in the rat was concluded to
be 175 ppm (17.5 mg/kg/day).
a. Ninety-day dog feeding. Groups of four male and four female
beagle dogs were dosed with pirimicarb by capsule at 0, 0.4 or 1.8 mg/
kg/day as an oral dose for a period of at least 90 days; a further
group received pirimicarb at 4 mg/kg/day for 180 days. There were no
adverse clinical or pathological effects, but the animals receiving 4
mg/kg/day showed evidence of increased erythropoetic activity on the
bone marrow. The NOAEL in this study was 1.8 mg/kg/day.
b. Twenty-one-day dermal study. Pirimicarb was assessed for its
sub-acute dermal toxicity. Groups of five male and five female rats
were given 15, 6-hour dermal applications of 40, 200, or 1,000 mg/kg
pirimicarb as a paste in deionized water over a period of 21 days.
There was no signs of skin irritation and no indications of systemic
toxicity. A small reduction in brain cholinesterase was found at 1,000
mg/kg. The NOAEL was 200 mg/kg.
5. Neurotoxicity-i. Acute neurotoxicity. In an acute neurotoxicity
study, pirimicarb was administered as a single dose at levels of 0, 10,
40, or 110 mg/kg body weight. The animals were observed up to 14 days.
A neurotoxicity screening battery of tests including a functional
observational battery and quantitative measurement of motor activity
was evaluated 1-week prior to the study, and on days 1, 8, and 15.
Administration of 110 mg/kg resulted in early mortalities and adverse
clinical signs. Brain neurotoxic esterase activity was not affected by
treatment. Changes at the 40 mg/kg dose were transient and not
accompanied by biologically significant reductions in brain or
erythrocyte cholinesterase activity. It is concluded that pirimicarb
shows reversible clinical signs of neurotoxicity following
administration of a single oral dose of 110 mg/kg. The NOAEL for
clinical signs of transient acute neurotoxicity is 40 mg/kg/day. The
NOAEL for this study is 10 mg/kg/day.
ii. Subchronic neurotoxicity. A subchronic rat neurotoxicity study
was performed. Pirimicarb was fed to rats at levels of 0, 75, 250, and
1,000 ppm for 90 days. A neurotoxicity screening battery of tests,
including functional observational battery and quantitative assessment
of motor activity was evaluated in week -1, 5, 9, and 14.
Histopathological assessment and neurotoxic esterase activity in the
brain was performed after 90 days. Reduced growth and food consumption/
utilization were observed at 250 and
[[Page 55920]]
1,000 ppm. There were no treatment-related effects on the functional
observational battery, motor activity, cholinesterase and neurotoxic
esterase activities and neuropathology. The NOAEL for subchronic
neurotoxicity was 1,000 ppm (approximately 81 mg/kg/day).
6. Chronic toxicity. In two chronic dog studies, dogs were dosed at
levels up to 25 mg/kg/day for either 1 or 2 years. Pirimicarb produced
hemolytic anemia or related hematological changes in a very small
proportion of dogs. This effect was shown to require prolonged
administration of pirimicarb and was reversible on cessation of
exposure to pirimicarb. It was not observed in toxicity studies in the
rat and mouse. A clear NOAEL of 3.5 mg/kg/day was established based on
hematological changes in all of the available studies.
In a 2-year rat combined chronic toxicity and oncogenicity study,
pirimicarb was fed for up to 2 years at 0, 75, 250, and 750 ppm. The
maximum tolerated dose was 750 ppm, with no carcinogenic response over
2 years. A NOAEL was established at 3.7 mg/kg/day.
In an 80-week mouse carcinogenicity study, the mice were given
pirimicarb at 0, 6.7, 26.6, and 93.5 mg/kg/day (0, 50 ppm, 200 ppm, and
700 ppm). It was concluded that there was an increase of incidence of
benign lung tumors in female at the top dose of 700 ppm, only. These
tumors are benign and demonstrate a clear threshold for induction,
leading to the conclusion that pirimicarb is not carcinogenic in the
mouse. This conclusion is further supported by evidence that pirimicarb
is non-genotoxic. A NOAEL of 26.6 mg/kg/day was established.
7. Animal metabolism. Radiolabeled studies in the rat and dog have
demonstrated that following oral administration, pirimicarb is well
absorbed, extensively metabolized, and the metabolites are rapidly
eliminated. Metabolism following a single oral dose is quantitatively
similar in rats and dogs and there is no evidence of bioaccumulation.
8. Metabolite toxicology. Pirimicarb and the carbamate metabolites
are associated with acute effects in cholinesterase inhibition.
9. Endocrine disruption. Pirimicarb shows no evidence of hormonal
effects, therefore there is no evidence of endocrine disruption. There
are no toxicity endpoints involving reproductive organs in either male
or female animals in any of these studies.
C. Aggregate Exposure
1. Dietary exposure. Pirimicarb is registered for non-food use on
seed alfalfa. The current request is to register pirimicarb on endive
(curly and escarole). An acute RfD of 0.1 mg/kg/day is proposed, based
on clinical signs of systemic toxicity seen at 40 mg/kg/day in the rat
acute neurotoxicity study and application of a standard 100-fold
uncertainty factor to the NOAEL of 10 mg/kg. There is no indication of
sensitivity to children and infants, and therefore, no requirement for
additional FQPA safety factor. The chronic RfD is 0.035 mg/kg/day,
based on hematological effects noted in the chronic dog studies at 4
mg/kg/day and application of a standard 100-fold uncertainty factor to
the NOAEL of 3.5 mg/kg/day.
i. Food--a. Acute risk. An acute dietary (food) risk assessment
(Dietary Exposure Evaluation Model, Novigen Sciences Inc., 1997; USDA
Continuing Survey of Food Intake by Individuals (CSFII) 1994-96) was
conducted using tolerance level residues for raw agricultural
commodities (RACs) and average field residues with percent crop treated
for blended commodities (apple juice and dried potatoes). Resulting
exposure values and percent of the acute RfD utilized are shown below:
Acute Dietary (Food only) exposure and risk for pirimicarb
------------------------------------------------------------------------
Exposure @ 99.9th
Population subgroup Percentile (mg/kg/ Percent Acute RfD
day)
------------------------------------------------------------------------
U.S. population (48 States)..... 0.005044 5.04%
Non-nursing infants (<1 year)... 0.000252 0.25%
Children (1-6 years)............ 0.003217 3.22%
Females (13-50)................. 0.005924 5.92%
------------------------------------------------------------------------
For pirimicarb, an acceptable acute dietary exposure (food plus
water) of 100% or less of the acute RfD for all population subgroups is
needed to protect the safety of all population subgroups. The estimated
exposure for all population subgroups at the 99.9th percentile utilized
less than 100% of the acute RfD, and does not exceed EPA's level of
concern.
b. Chronic risk. Chronic dietary risk assessments (Dietary Exposure
Evaluation Model, Novigen Sciences Inc., 1997; USDA Continuing Survey
of Food Intake by Individuals (CSFII) 1994-96) were conducted for
pirimicarb using two approaches: (1) using tolerance level residues and
assuming 100% crop treated, and (2) using anticipated residue
concentration levels adjusted for percent crop treated and limit of
detection residues. The Theoretical Maximum Residue Contribution (TMRC)
and Anticipated Residue Contribution (ARC) from these two scenarios
represents 0.3% and 0.1%, respectively, of the RfD for the U.S.
population as a whole. The subgroup with the greatest chronic exposure
is children ages one to six for which the TMRC and ARC estimates
represented 0.4% and 0.1%, respectively of the RfD. The chronic dietary
risks from these uses do not exceed EPA's level of concern.
ii. Drinking water. Other potential sources of exposure of the
general population are residues in drinking water. Laboratory data on
pirimicarb indicate that its potential soil mobility ranges between low
and very high, depending on a number of factors including pH. However
field dissipation data on both the parent and its metabolites indicate
that under agricultural conditions, degradation is so rapid (half-lives
< 21 days) that significant leaching does not occur. In a 1995-96 field
dissipation study conducted using 14C labeled material, the
half-life of pirimicarb was found to average 3.1 days, and no
radioactive residue (pirimicarb and/or metabolites) of greater than
0.01 ppm was found below 6 inches in depth. This study conducted in
1995-96 confirms previous laboratory and field dissipation studies.
Pirimicarb is rapidly dissipated under field conditions by both
photolysis and microbial metabolism leading to significantly less
persistence than demonstrated under conditions of laboratory soil
degradation studies. This rapid dissipation under field conditions is
independent of soil pH. Pirimicarb, therefore, does not leach and is
unlikely to enter surface water under the conditions of the recommended
label use patterns.
Drinking water levels of comparison (DWLOC) were calculated for
pirimicarb for adults and children for both acute and chronic
exposures, in accordance with EPA's Standard Operating Procedure (SOP)
for Drinking Water Exposure and Risk Assessments (November 20, 1997).
Drinking water exposure from surface and ground water for pirimicarb
was estimated using Tier II model EPA's pesticide root zone model
(PRZM)/EXAMS and Tier I model SCI-GROW, respectively. The exposure
estimates and DWLOCs are summarized below:
[[Page 55921]]
Drinking Water Levels of Comparison and Acute Exposure Estimates for Pirimicarb
----------------------------------------------------------------------------------------------------------------
Population subgroup SCI-GROW (ug/L)\1\ PRZM/EXAMS (ug/L)\2\ Acute DWLOC (ug/L)
----------------------------------------------------------------------------------------------------------------
Adult - U.S. population.............. 0.25 4.66 3323
Children............................. 0.25 4.66 968
----------------------------------------------------------------------------------------------------------------
\1\ SCI-GROW estimate based on highest water estimate from all crop uses.
\2\ PRZM/EXAMS based on instantaneous concentration for total carbamate residues (parent + metabolites)
Drinking Water Levels of Comparison and Chronic Exposure Estimates for Pirimicarb
----------------------------------------------------------------------------------------------------------------
Population subgroup SCI-GROW (ug/L)\1\ PRZM/EXAMS (ug/L)\2\ Chronic DWLOC (ug/L)
----------------------------------------------------------------------------------------------------------------
Adult - U.S. population.............. 0.25 0.88 1224
Children............................. 0.25 0.88 350
----------------------------------------------------------------------------------------------------------------
\1\ SCI-GROW estimate based on highest water estimate from all crop uses.
\2\ PRZM/EXAMS based on annualized average value for total carbamate residues (parent + metabolites).
Based on the estimated dietary and water exposures for pirimicarb,
Zeneca has concluded that there is a reasonable certainty of no harm to
infants, children and adults resulting from potential acute or chronic
aggregate exposure to pirimicarb.
2. Non-dietary exposure. Pirimicarb is not registered for either
indoor or outdoor residential uses. There are no non-occupational
exposures to pirimicarb. Non-food uses for alfalfa grown for seed and
small seeded vegetable seeds are occupational exposures. These
exposures are represented in inhalation, oral and dermal estimates
contained in the acute toxicology summaries, as well as the dermal
penetration studies.
D. Cumulative Effects
Pirimicarb, as a carbamate insecticide, exerts its insecticidal
effect through inhibition of acetyl-cholinesterase. At this time,
methodologies and mechanistic data are not available to resolve this
complex issue of cumulative effects concerning common mechanisms of
toxicity. At this time, there are no available data to determine
whether pirimicarb has a common mechanism of toxicity with other
substances, or how to include this pesticide in a cumulative risk
assessment.
E. Safety Determination
1. U.S. population. Based on the available toxicity data, a chronic
RfD is set for pirimicarb at 0.035 mg/kg/day. This RfD is based on
chronic dog studies with a NOAEL of 3.5 mg/kg/day and an uncertainty
factor of 100. The acute RfD is 0.01 mg/kg/day, based on clinical signs
of toxicity at 40 mg/kg/day in the rat acute neurotoxicity study. No
additional uncertainty factors are necessary.
2. Infants and children. Developmental toxicity and reproductive
toxicity studies have not shown fetal effects other than mild
fetotoxicity in the rat (reduced fetus/litter weight and indications of
delayed development) at doses which were also toxic to the mother.
There was no evidence in these studies of any extra susceptibility of
the fetus. Neither has there been any indication of any particular
susceptibility of juvenile animals. Based on the data base, there is no
reason to consider human infants and children to be inherently more at
risk of toxicity from pirimicarb than adults.
FFDCA section 408 provides that EPA may apply an additional safety
factor for infants and children in the case of threshold effects to
account for prenatal and postnatal toxicity and the completeness of the
data base. Based on the current toxicological data requirements, the
data base relative to prenatal and postnatal effects for children is
complete. No additional FQPA safety factor is required for pirimicarb.
F. International Tolerances
The CODEX maximum residue levels for pirimicarb and its carbamate
metabolites (desmethyl and desmethyl formamido pirimicarb) are:
potatoes 0.05 ppm, lettuce 1.0 ppm, and apples (pome fruit) 1.0 ppm.
[FR Doc. 99-26971 Filed 10-14-99; 8:45 am]
BILLING CODE 6560-50-F