[Federal Register Volume 62, Number 228 (Wednesday, November 26, 1997)]
[Rules and Regulations]
[Pages 62954-62961]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-30946]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300576; FRL-5754-9]
RIN 2070-AB78
Tefluthrin; Pesticide Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation establishes tolerances for combined residues
of tefluthrin and its metabolite in or on corn, grain, field and pop;
corn, forage and fodder, field, pop and sweet; and corn, fresh
(including sweet K and corn with husk removed (CWHR)) at 0.06 parts per
million (ppm). It also removes time limitations for tolerances for
residues of tefluthrin on the same commodities that expire on November
15, 1997. Zeneca Ag Products requested these tolerances under the
Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by the Food
Quality Protection Act of 1996 (Pub. L. 104-170).
DATES: This regulation is effective November 26, 1997. Objections and
requests for hearings must be received by EPA on or before January 26,
1998.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [OPP-300576], 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-300576], 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. 1132, 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: [email protected]. Copies of objections and
hearing requests must be submitted as an ASCII file avoiding the use of
special characters and any form of encryption. Copies of objections and
hearing requests will also be accepted on disks in WordPerfect 5.1 file
format or ASCII file format. All copies of objections and hearing
requests in electronic form must be identified by the docket control
number [OPP-300576]. 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: Beth Edwards, Registration
Division 7505C, Office of Pesticide Programs, Environmental Protection
Agency, 401 M St., SW., Washington, DC 20460. Office location,
telephone number, and e-mail address: Crystal Mall #2, 1921 Jefferson
Davis Hwy., Arlington, VA, (703) 305-5400, e-mail:
[email protected].
SUPPLEMENTARY INFORMATION: On February 1, 1989 (54 FR 5080), EPA
established time limited tolerances under Section 408 of the Federal
Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346 a(d) and 348 for
residues of tefluthrin on corn, grain, field, and pop; corn, forage and
fodder, field and pop. As additional crop tolerances were established,
they were also made time-limited. These tolerances expire on November
15, 1997. Zeneca Ag Products, on September 15, 1997, requested that the
time limitation for tolerances established for residues of the
insecticide tefluthrin in the corn commodities mentioned above be
removed based on environmental effects data that they had submitted as
a condition of the registration. Zeneca Ag Products also submitted a
summary of its petition as required under the FFDCA as amended by the
Food Quality Protection Act (FQPA) of 1996 (Pub. L. 104-170).
In the Federal Register of September 25, 1997 (62 FR 50337) (FRL-
5748-2), EPA issued a notice pursuant to section 408 of the Federal
Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(e) announcing the
filing of a pesticide petitions (PP 7F3521 and 4F4406) for tolerances
by Zeneca Ag Products, P.O. Box 15458, Wilmington, DE, 19850-5458. This
notice included a summary of the petition prepared by Zeneca Ag
Products, the registrant. There were no comments received in response
to the notice of filing.
The petitions requested that 40 CFR 180.440 be amended by removing
the time-limitation for tolerances for combined residues of the
insecticide and pyrethroid tefluthrin and its metabolite (Z)-3-(2-
chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylic
acid, in or on corn, grain, field and pop; corn, forage and fodder,
field, pop and sweet; and corn, fresh (including sweet K and corn with
husk removed (CWHR)) at 0.06 part per million (ppm).
The basis for the time-limited tolerances that expire November 15,
1997, was given in the Federal Register of October 20, 1993 (58 FR
54094). These time-limited tolerances were predicated on the expiration
of pesticide product registrations that were made conditional due to
lack of certain ecological and environmental effects data. The
rationale for using time-limited tolerances was to encourage pesticide
manufacturers to comply with the conditions of registration in a timely
manner. There is no regulatory requirement to make tolerances time-
limited due to the conditional status of a product registration under
the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), as
amended. It is current EPA policy to no longer establish time
limitations on tolerance(s) with expiration dates if none of the
conditions of registration have any bearing on human dietary risk. The
current petition action meets that condition and thus the expiration
dates associated with specific crop tolerances are being deleted.
I. Risk Assessment and Statutory Findings
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
[[Page 62955]]
children to the pesticide chemical residue in establishing a tolerance
and to ``ensure that there is a reasonable certainty that no harm will
result to infants and children from aggregate exposure to the pesticide
chemical residue....''
EPA performs a number of analyses to determine the risks from
aggregate exposure to pesticide residues. First, EPA determines the
toxicity of pesticides based primarily on toxicological studies using
laboratory animals. These studies address many adverse health effects,
including (but not limited to) reproductive effects, developmental
toxicity, toxicity to the nervous system, and carcinogenicity. Second,
EPA examines exposure to the pesticide through the diet (e.g., food and
drinking water) and through exposures that occur as a result of
pesticide use in residential settings.
A. Toxicity
1. Threshold and non-threshold effects. For many animal studies, a
dose response relationship can be determined, which provides a dose
that causes adverse effects (threshold effects) and doses causing no
observed effects (the ``no-observed effect level'' or ``NOEL'').
Once a study has been evaluated and the observed effects have been
determined to be threshold effects, EPA generally divides the NOEL from
the study with the lowest NOEL by an uncertainty factor (usually 100 or
more) to determine the Reference Dose (RfD). The RfD is a level at or
below which daily aggregate exposure over a lifetime will not pose
appreciable risks to human health. An uncertainty factor (sometimes
called a ``safety factor'') of 100 is commonly used since it is assumed
that people may be up to 10 times more sensitive to pesticides than the
test animals, and that one person or subgroup of the population (such
as infants and children) could be up to 10 times more sensitive to a
pesticide than another. In addition, EPA assesses the potential risks
to infants and children based on the weight of the evidence of the
toxicology studies and determines whether an additional uncertainty
factor is warranted. Thus, an aggregate daily exposure to a pesticide
residue at or below the RfD (expressed as 100% or less of the RfD) is
generally considered acceptable by EPA. EPA generally uses the RfD to
evaluate the chronic risks posed by pesticide exposure. For shorter
term risks, EPA calculates a margin of exposure (MOE) by dividing the
estimated human exposure into the NOEL from the appropriate animal
study. Commonly, EPA finds MOEs lower than 100 to be unacceptable. This
100-fold MOE is based on the same rationale as the 100-fold uncertainty
factor.
Lifetime feeding studies in two species of laboratory animals are
conducted to screen pesticides for cancer effects. When evidence of
increased cancer is noted in these studies, the Agency conducts a
weight of the evidence review of all relevant toxicological data
including short-term and mutagenicity studies and structure activity
relationship. Once a pesticide has been classified as a potential human
carcinogen, different types of risk assessments (e.g., linear low dose
extrapolations or MOE calculation based on the appropriate NOEL) will
be carried out based on the nature of the carcinogenic response and the
Agency's knowledge of its mode of action.
2. Differences in toxic effect due to exposure duration. The
toxicological effects of a pesticide can vary with different exposure
durations. EPA considers the entire toxicity data base, and based on
the effects seen for different durations and routes of exposure,
determines which risk assessments should be done to assure that the
public is adequately protected from any pesticide exposure scenario.
Both short and long durations of exposure are always considered.
Typically, risk assessments include ``acute,'' ``short-term,''
``intermediate term,'' and ``chronic'' risks. These assessments are
defined by the Agency as follows.
Acute risk, by the Agency's definition, results from 1-day
consumption of food and water, and reflects toxicity which could be
expressed following a single oral exposure to the pesticide residues.
High end exposure to food and water residues are typically assumed.
Short-term risk results from exposure to the pesticide for a period
of 1-7 days, and therefore overlaps with the acute risk assessment.
Historically, this risk assessment was intended to address primarily
dermal and inhalation exposure which could result, for example, from
residential pesticide applications. However, since enaction of FQPA,
this assessment has been expanded to include both dietary and non-
dietary sources of exposure, and will typically consider exposure from
food, water, and residential uses when reliable data are available. In
this assessment, risks from average food and water exposure, and high-
end residential exposure, are aggregated. High-end exposures from all 3
sources are not typically added because of the very low probability of
this occurring in most cases, and because the other conservative
assumptions built into the assessment assure adequate protection of
public health. However, for cases in which high-end exposure can
reasonably be expected from multiple sources (e.g. frequent and
widespread homeowner use in a specific geographical area), multiple
high-end risks will be aggregated and presented as part of the
comprehensive risk assessment/characterization. Since the toxicological
endpoint considered in this assessment reflects exposure over a period
of at least 7 days, an additional degree of conservatism is built into
the assessment; i.e., the risk assessment nominally covers 1-7 days
exposure, and the toxicological endpoint/NOEL is selected to be
adequate for at least 7 days of exposure. (Toxicity results at lower
levels when the dosing duration is increased.)
Intermediate-term risk results from exposure for 7 days to several
months. This assessment is handled in a manner similar to the short-
term risk assessment.
Chronic risk assessment describes risk which could result from
several months to a lifetime of exposure. For this assessment, risks
are aggregated considering average exposure from all sources for
representative population subgroups including infants and children.
B. Aggregate Exposure
In examining aggregate exposure, FFDCA section 408 requires that
EPA take into account available and reliable information concerning
exposure from the pesticide residue in the food in question, residues
in other foods for which there are tolerances, residues in ground water
or surface water that is consumed as drinking water, and other non-
occupational exposures through pesticide use in gardens, lawns, or
buildings (residential and other indoor uses). Dietary exposure to
residues of a pesticide in a food commodity are estimated by
multiplying the average daily consumption of the food forms of that
commodity by the tolerance level or the anticipated pesticide residue
level. The Theoretical Maximum Residue Contribution (TMRC) is an
estimate of the level of residues consumed daily if each food item
contained pesticide residues equal to the tolerance. In evaluating food
exposures, EPA takes into account varying consumption patterns of major
identifiable subgroups of consumers, including infants and children.
The TMRC is a ``worst case'' estimate since it is based on the
assumptions that food contains pesticide residues at the tolerance
level and that 100% of the crop is treated by
[[Page 62956]]
pesticides that have established tolerances. If the TMRC exceeds the
RfD or poses a lifetime cancer risk that is greater than approximately
one in a million, EPA attempts to derive a more accurate exposure
estimate for the pesticide by evaluating additional types of
information (anticipated residue data and/or percent of crop treated
data) which show, generally, that pesticide residues in most foods when
they are eaten are well below established tolerances.
II. Aggregate Risk Assessment and Determination of Safety
Consistent with section 408(b)(2)(D), EPA has reviewed the
available scientific data and other relevant information in support of
this action, EPA has sufficient data to assess the hazards of
tefluthrin and to make a determination on aggregate exposure,
consistent with section 408(b)(2), for combined residues of tefluthrin
and its metabolite on corn, grain, field and pop; corn, forage and
fodder, field, pop and sweet; and corn, fresh (including sweet K and
corn with husk removed (CWHR)) at 0.06 ppm. EPA's assessment of the
dietary exposures and risks associated with establishing the tolerance
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 tefluthrin are
discussed below.
1. Acute toxicity studies with the technical grade of the active
ingredient tefluthrin: oral LD50 in the rat is 21.8
milligrams/kilogram (mg/kg) for males and 34.6 mg/kg for females -
Toxicity Category I; dermal LD50 in the rat is 316 mg/kg in
males and 177 mg/kg in females - Toxicity Category I; acute inhalation
LC50 in the rat is 0.037 mg/l and 0.049 mg/l in male and
female rats, respectively - Toxicity Category I; the primary eye
irritation study in the rabbit was an invalid study; primary dermal
irritation study in the rabbit showed slight irritation - Toxicity
Category IV; dermal sensitization study in the guinea pig showed no
skin sensitization; and the acute delayed neurotoxicity study did not
show acute delayed neurotoxicity.
2. In an oral toxicity study, rats were dosed at 0, 25, 100, or 400
ppm (1.25, 5, or 20 milligrans/kilogram/day) (mg/kg/day) for 21 days.
The LOEL for females for this 21-day oral toxicity study is 400 ppm
(equivalent to approximately 20 mg/kg/day) based on decreased body
weight gain, decreased platelet counts, and increased WBC and
lymphocytes in the high-dose females. The NOEL for females is 100 ppm
(equivalent to approximately 5 mg/kg/day). The NOEL in males was not
observed.
3. In a subchronic oral toxicity study, rats were dosed at 0, 50,
150, or 350 ppm (2.5, 7.5, or 17.5 mg/kg/day) for 90 days. The LOEL for
this 90-day feeding study is 150 ppm (equivalent to approximately 7.5
mg/kg/day) based on changes in hemoglobin, cholesterol, and liver
weight in the mid-dose animals. The NOEL is 50 ppm (equivalent to
approximately 2.5 mg/kg/day).
4. In a subchronic oral toxicity study, dogs were dosed at 0, 0.1,
0.5, or 1.5 mg/kg/day for 90 days. The LOEL for this 90-day oral
toxicity study is 1.5 mg/kg/day based on thyroid changes, and increased
levels of plasma triglycerides and aspartate transaminase observed at
the high-dose. The NOEL is 0.5 mg/kg/day.
5. In an oral toxicity study, mice were dosed at 0, 25, 75, 200, or
400 ppm (0, 3.75, 11.3, 30.0, or 60.0 mg/kg/day) for 28 days. The LOEL
is 400 ppm (equivalent to approximately 60 mg/kg/day) based on
decreased body weight gains in both sexes and final body weights in
females. The NOEL is 200 ppm (equivalent to approximately 30 mg/kg/
day).
6. In a dermal toxicity study, rats were dosed at 0, 0.1, 1.0, or
50 mg/kg. The LOEL for skin effects for this 21-day dermal toxicity
study is 50.0 mg/kg based on acanthosis, necrosis epidermis, and
inflammatory cell infiltrate dermis observed in the high-dose animals.
The NOEL for skin effects is 1.0 mg/kg). The NOEL for neurological
effects (the observed postural effects) may be between 0.025 and 0.1
mg/kg.
7. In a chronic/oncogenicity study, mice were dosed at 0, 25, 100,
or 400 ppm (actual dose levels were equivalent to 3.4, 13.5, or 54.4
mg/kg/day) for 104 weeks. The chronic LOEL is 13.5 mg/kg based on
hemangiomatous changes of the uterus and liver necrosis observed in the
mid- and high-dose females. The chronic NOEL is 3.4 mg/kg. Under the
conditions of this study, there was no evidence of carcinogenic
potential.
8. In a chronic toxicity study, dogs were dosed at dose levels of
0, 0.1, 0.5, and 2 mg/kg/day for 12 months. The LOEL for this chronic
study is 2.0 mg/kg/day based on the increased incidence of ataxia in
both sexes at the high-dose. The NOEL is 0.5 mg/kg/day.
9. In a chronic/oncogenicity study, rats were dosed for 24 months
at 0, 25, 100, or 400 ppm (actual dose levels were equivalent to 1.1,
4.6, or 18.2 mg/kg/day). The chronic LOEL is 4.6 mg/kg/day based on
decreased body weights, and neurotoxicity and clinical chemistry
changes in the mid- and high-dose animals. The chronic NOEL is 1.1 mg/
kg/day. Under the conditions of this study, there was no evidence of
carcinogenic potential.
10. In a developmental toxicity study, rats were dosed at 0, 1, 3,
or 5 mg/kg/day from days 7 through 16 of gestation. The maternal LOEL
is 3 mg/kg/day, based on treatment-related decrease body weight gains
during dosing. The maternal NOEL is 1 mg/kg/day. Developmental toxicity
was demonstrated at 5 mg/kg/day as an increase in the fetal incidence
of bilaterally unossified calcanea (92.9% vs. 87.5% in controls,
p<0.05; litter incidence was not shown) and a slight increase in the
pes score (3.05 vs. 2.96 in controls) indicating slight inhibition of
ossification at these sites. There were no treatment-related effects on
the number, growth, and survival of the young in utero. In addition,
the inter-group differences in the mean numbers of corpora lutea,
implantations, pre- and post- implantation deaths, live fetuses,
proportion of male fetuses, and fetal weights were not remarkable. The
developmental LOEL is 5 mg/kg/day, based on inhibited ossification. The
developmental NOEL is 3 mg/kg/day.
11. In a developmental toxicity study, rabbits were dosed at 0, 3,
6, or 12 mg/kg/day from days 7 through 19 of gestation. The maternal
LOEL is 3 mg/kg/day, based on treatment-related clinical signs of
toxicity (tremors). The maternal NOEL is <3 mg/kg/day. There was no
developmental toxicity demonstrated at any dose level. There were no
treatment-related effects on in utero survival and growth or on litter
size and sex ratio of the fetuses. The skeletal variant data showed
significant (p<0.01 or 0.05) increases in incidence of extra thoracic
ribs and 27 pre-sacral vertebrae among fetuses in the dosed groups;
however, when the litter was used as the unit for comparison, the
incidences of these respective variants were comparable between all
groups. The incidences of these variants were not biologically
significant. The NOEL for developmental toxicity is 12 mg/kg/day. The
developmental LOEL was not observed.
12. In a multi-generation reproduction study, rats were dosed at 0,
15, 50, or 250 ppm (0, 0.75, 2.5, or 12.5 mg/kg/day). The LOEL for
parental toxicity is 12.5 mg/kg/day, based on lowered body
[[Page 62957]]
weight gains, and the NOEL is 2.5 mg/kg/day. The LOEL for neurotoxic
effects is 2.5 mg/kg/day, based on abnormal, splayed, or high-stepping
gait. The NOEL for neurotoxic effects is 0.75 mg/kg/day. Reproductive
toxicity was demonstrated at the high-dose as lowered pup body weight
gain throughout the study in all generations and in both sexes.
Additionally, total litter weight was decreased on day 29 in all of the
high-dose groups. The LOEL for reproductive toxicity is 12.5 mg/kg/day,
based on lowered pup body weight gains. The reproductive NOEL is 2.5
mg/kg/day.
13. Mutagenicity. There is no mutagenicity concern. The submitted
studies satisfy the pre-1991 mutagenicity test battery and the new
mutagenicity testing requirements. There are seven acceptable studies:
one dominant lethal study in mice; reverse mutation assay (Salmonella
typhimurium); one forward mutation assay in mammalian cells; one mouse
lymphoma assay, one in vivo chromosomal aberration assay, in vitro
chromosome aberration study; one UDS assay in primary rat hepatocytes.
All these studies were negative.
14. Metabolism. In both rats and dogs, when given either 1 or 10
mg/kg, most of the radioactivity was found in the feces unchanged and
most urinary metabolites were conjugated. Approximately 30% of the
administered dose was absorbed and excreted in the urine in both
species. Single doses in both rats and dogs were excreted within 48
hours, 50-65% in feces and 20-30% in the urine. In rats, a biliary
fistula experiment suggested that the radioactivity measured in the
feces may be partially due to biliary excretion. Studies also suggest
that oxidation precedes the ester body cleavage. In rats, the halflife
in the liver is 4.8 days, in the fat is 13.3 days and in the blood is
10.6 days. In a study with rat fat, half of the radioactive residues
could be attributed to the parent and the remaining residues consisted
of a mixture of fatty acid esters of hydroxylated parent metabolites.
15. Neurotoxicity. No acceptable mammalian neurotoxicity studies
are available. In a supplementary study, 10 animals/sex/group were
given either vehicle, 2,5-hexanedione or 5 mg/kg or 15 mg/kg
tefluthrin. The positive control, 2,5-hexanedione, elicited the
appropriate neurotoxicological response. No consistent effects on motor
or sensory nerve electrophysiology or function or clinical signs of
neurotoxicity were evident in animals treated with either 5 or 15 mg/kg
tefluthrin. A slight but significant increase in pull-up time was
observed on day 12 in males which was accompanied by a significant
decrease in both SNCV and the amplitude of the SNAP. Both quickly
returned to values similar to control values, and did not decrease
again.
Neurotoxicity studies will be required under a special Data Call-In
letter pursuant to section 3(c)(2)(B) of FIFRA. Although these data are
lacking, EPA has sufficient toxicity data to support these tolerances
and these additional studies are not expected to significantly change
the risk assessment.
B. Toxicological Endpoints
1. Acute toxicity. For acute dietary risk assessment, EPA
recommends use of a NOEL of 0.5 mg/kg/day based on increased incidence
of tremors and ataxia in both sexes of dogs at 2.0 mg/kg/day (LOEL) on
day 1 of the study from the 1 year oral chronic toxicity study in dogs.
2. Short - and intermediate - term toxicity. For short- and
intermediate term MOE's, EPA recommends use of a NOEL of 0.5 mg/kg/day
based on increased incidence of tremors and ataxia in both sexes of
dogs at 2.0 mg/kg/day (LOEL) from the one year oral toxicity study in
dogs and use of a dermal absorption rate of 25%. A dermal absorption
rate of 25% was recommended based on the weight-of-the-evidence
available for structurally related pyrethroids.
3. Chronic toxicity. EPA has established the RfD for tefluthrin at
0.005 milligrams/kilogram/day (mg/kg/day). This RfD is based on
increased incidence of tremors and ataxia in both sexes of dogs in a
chronic toxicity study and an uncertainty factor of 100 to account for
both interspecies extrapolation and intraspecies variability.
4. Carcinogenicity. No evidence of carcinogenicity was demonstrated
in studies conducted with mice or rats.
C. Exposures and Risks
1. From food and feed uses.Tolerances have been established (40 CFR
180.440) for the combined residues of tefluthrin and its metabolite, in
or on corn. Risk assessments were conducted by EPA to assess dietary
exposures and risks from tefluthrin 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. Percent of crop treated data and
tolerance values were used in conjunction with Monte Carlo. The acute
dietary MOE at the 99.9th percentile for the most highly exposed
population subgroup (non-nursing infants <1 year old) is 691. The MOE
at the 99.9th percentile for the general U.S. population is 1,469. EPA
concludes that there is a reasonable certainty of no harm for MOEs of
100 or greater. Therefore, the acute dietary risk assessment for
tefluthrin indicates a reasonable certainty of no harm.
ii. Chronic exposure and risk. The chronic dietary exposure
assessment used tolerance values and percent crop treated information.
The RfD used for the chronic dietary analysis is 0.005 mg/kg/day. The
risk assessment resulted in use of less than one percent (0.1%) of the
RfD for the U.S. population. The percent of the RfD used for the most
highly exposed population subgroup (children ages one to six) is 0.3%.
EPA notes that the acute dietary risk assessments used Monte Carlo
modeling (in accordance with Tier 3 of EPA June 1996 ``Acute Dietary
Exposure Assessment'' guidance document) incorporating tolerance levels
and percent of crop treated refinements. The chronic dietary risk
assessments used tolerance levels and percent crop treated information.
Section 408(b)(2)(E) authorizes EPA to consider available data and
information on the anticipated residue levels of pesticide residues in
food and the actual levels of pesticide chemicals that have been
measured in food. If EPA relies on such information, EPA must require
that data be provided five years after the tolerance is established,
modified or left in effect, demonstrating that the levels in food are
not above the levels anticipated. Following the initial data
submission, EPA is authorized to require similar data on a timeframe it
deems appropriate. Section 408(b)(2)(F) allows the Agency to use data
on the actual percent of crop treated when establishing a tolerance
only where the Agency can make the following findings: (1) that the
data used are reliable and provide a valid basis for showing the
percentage of food derived from a crop that is likely to contain
residues; (2) that the exposure estimate does not underestimate the
exposure for any significant subpopulation and; (3) where data on
regional pesticide use and food consumption are available, that the
exposure estimate does not understate exposure for any regional
population. In addition, the Agency must provide for periodic
evaluation of any estimates used.
The percent of crop treated estimates for tefluthrin were derived
from federal and market survey data. EPA considers these data reliable.
A range of estimates
[[Page 62958]]
are supplied by this data and the upper end of this range was used for
the exposure assessment. By using this upper end estimate of percent
crop treated, the Agency is reasonably certain that exposure is not
underestimate for any significant subpopulation. Further, regional
consumption information is taken into account through EPA's computer-
based model for evaluating the exposure of significant subpopulations
including several regional groups. Review of this regional data allows
the Agency to be reasonably certain that no regional population is
exposed to residue levels higher than those estimated by the Agency. To
meet the requirement for data on anticipated residues, EPA will issue a
Data Call-In (DCI) notice pursuant to FFDCA section 408(f) requiring
submission of data on anticipated residues in conjunction with approval
of the registration under the FIFRA.
2. From drinking water. Tefluthrin is immobile in soil and,
therefore, will not leach into ground water. Additionally, due to the
insolubility and lipophilic nature of tefluthrin, any residues in
surface water will rapidly and tightly bind to soil particles and
remain with sediment, therefore not contributing to potential dietary
exposure from drinking water.
A screening evaluation of leaching potential of a typical synthetic
pyrethroid was conducted using EPA's Pesticide Root Zone Model (PRZM).
Based on this screening assessment, potential concentrations of a
pyrethroid in ground water at depths of 1 to 2 meters are essentially
zero (<0.001 ppb). Surface water concentrations for pyrethroids were
estimated using PRZM1 and Exposure Analysis Modeling Systems (EXAMS)
using standard EPA cotton runoff and Mississippi pond scenarios. The
maximum concentration predicted in the simulation pond was 0.052 ppb.
Concentrations in actual drinking water would be much lower than the
levels predicted in the hypothetical, small, stagnant farm pond model
since drinking water derived from surface water would normally be
treated before consumption. Based on these analyses, the contribution
of water to the dietary risk estimate is negligible. Therefore, EPA
concludes that together these data indicate that residues are not
expected to occur in drinking water.
i. Acute exposure and risk. The acute drinking water exposure and
risk estimates are 0.000040 mg/kg/day (MOE of 12,362) and 0.000078 mg/
kg/day (MOE of 6,439) for the overall U.S. population and non-nursing
infants <1 year old, respectively.
ii. Chronic exposure and risk. The chronic drinking water exposure
and risk estimates are 0.000000 mg/kg/day (0.0% of RfD utilized) and
0.000002 mg/kg/day (0.0% of RfD utilized) for the overall U.S.
population and non-nursing infants <1 year old, respectively.
3. From non-occupational non-dietary exposure. Tefluthrin is
currently not registered for use on residential non-food sites;
therefore, no non-occupational non-dietary exposure is expected.
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.'' The Agency believes that ``available
information'' in this context might include not only toxicity,
chemistry, and exposure data, but also scientific policies and
methodologies for understanding common mechanisms of toxicity and
conducting cumulative risk assessments. For most pesticides, although
the Agency has some information in its files that may turn out to be
helpful in eventually determining whether a pesticide shares a common
mechanism of toxicity with any other substances, EPA does not at this
time have the methodologies to resolve the complex scientific issues
concerning common mechanism of toxicity in a meaningful way. EPA has
begun a pilot process to study this issue further through the
examination of particular classes of pesticides. The Agency hopes that
the results of this pilot process will increase the Agency's scientific
understanding of this question such that EPA will be able to develop
and apply scientific principles for better determining which chemicals
have a common mechanism of toxicity and evaluating the cumulative
effects of such chemicals. The Agency anticipates, however, that even
as its understanding of the science of common mechanisms increases,
decisions on specific classes of chemicals will be heavily dependent on
chemical specific data, much of which may not be presently available.
Although at present the Agency does not know how to apply the
information in its files concerning common mechanism issues to most
risk assessments, there are pesticides as to which the common mechanism
issues can be resolved. These pesticides include pesticides that are
toxicologically dissimilar to existing chemical substances (in which
case the Agency can conclude that it is unlikely that a pesticide
shares a common mechanism of activity with other substances) and
pesticides that produce a common toxic metabolite (in which case common
mechanism of activity will be assumed).
EPA does not have, at this time, available data to determine
whether tefluthrin 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,
tefluthrin 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 tefluthrin has a common mechanism of toxicity
with other substances.
D. Aggregate Risks and Determination of Safety for U.S. Population
1. Acute risk. The acute aggregate risk assessment takes into
account exposure from food and water. The acute aggregate MOE
calculated at the 99.9th percentile for the overall U.S. population is
1,316. The Agency has no cause for concern if total acute exposure
calculated for the 99.9th percentile yields an MOE of 100 or larger.
Therefore, the Agency concludes that there is reasonable certainty that
no harm will result from acute aggregate exposure to tefluthrin
residues in food and drinking water.
2. Chronic risk. Using the Anticipated Residue Concentration (ARC)
exposure assumptions described above, EPA has concluded that aggregate
exposure to tefluthrin from food and water will utilize 0.1% of the RfD
for the U.S. population. The major identifiable subgroup with the
highest aggregate exposure is children age 1-6 years (discussed below).
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. EPA concludes that there is a reasonable certainty that
no harm will result from aggregate exposure to tefluthrin residues.
3. 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. Based on tefluthrin not being registered for
residential non-food sites, EPA concludes that the aggregate short- and
intermediate-term risks do not
[[Page 62959]]
exceed levels of concern (MOE less than 100), and that there is
reasonable certainty that no harm will result from aggregate exposure
to tefluthrin residues.
E. Aggregate Cancer Risk for U.S. Population
No evidence of carcinogenicity was demonstrated in studies
conducted mice or rats.
F. 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 tefluthrin, EPA considered data from
developmental toxicity studies in the rat and rabbit and a two-
generation reproduction study in the rat. The developmental toxicity
studies are designed to evaluate adverse effects on the developing
organism resulting from pesticide exposure during prenatal development
to one or both parents. Reproduction studies provide information
relating to effects from exposure to the pesticide on the reproductive
capability of mating animals and data on systemic toxicity.
FFDCA section 408 provides that EPA shall apply an additional
tenfold margin of safety for infants and children in the case of
threshold effects to account for pre-and post-natal toxicity and the
completeness of the data base unless EPA determines that a different
margin of safety will be safe for infants and children. Margins of
safety are incorporated into EPA risk assessments either directly
through use of a MOE analysis or through using uncertainty (safety)
factors in calculating a dose level that poses no appreciable risk to
humans. EPA believes that reliable data support using the standard 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 prenatal developmental
toxicity studies in rats and rabbits, the developmental NOEL was
greater than the maternal NOEL, indicating a lack of sensitivity to in
utero exposure. In rats, the maternal NOEL (1 mg/kg/day), based on body
weight decreases at the LOEL of 3 mg/kg/day, which was based on
ossification reductions in the extremities at 5 mg/kg/day. In the
rabbit study, maternal pyrethroid toxicity was observed at all dose
levels (maternal NOEL <3 mg/kg/day), but no developmental toxicity was
observed (developmental NOEL >12 mg/kg/day).
iii. Reproductive toxicity study. In the two-generation
reproduction study in rats, offspring toxicity (reduced mean pup weight
gain) was observed only at the highest dose level tested (250 ppm; 12.5
mg/kg/day), while evidence of neurotoxicity in parental animals was
observed at the systemic LOEL of 50 ppm (2.5 mg/kg/day). The offspring
toxicity NOEL was 50 ppm (2.5 mg/kg/day) and the parental systemic NOEL
was 15 ppm (0.75 mg/kg/day).
iv. Pre- and post-natal sensitivity. The data demonstrated no
indication of increased sensitivity of rats or to in utero and/or
postnatal exposure with tefluthrin.
v. Conclusion. The data base related to pre- and post-natal
sensitivity is complete. Based on the above, EPA concludes that
reliable data support use of the standard 100-fold uncertainty factor,
and that an additional uncertainty factor is not needed to protect the
safety of infants and children.
2. Acute risk. The acute aggregate MOE calculated at the 99.9th
percentile for non-nursing infants <1 year old is 623. EPA concluded
that aggregate dietary acute risk (food plus water) would not exceed
levels of concern. Therefore, the Agency has no acute aggregate concern
due to exposure to tefluthrin through food and drinking water.
3. Chronic risk. Using the conservative exposure assumptions
described above, EPA has concluded that aggregate exposure to
tefluthrin from food and water will utilize 0.3% of the RfD for
children age 1-6 years. 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.
4. Short- or intermediate-term risk. Based on tefluthrin not being
registered for residential non-food sites, EPA concludes that the
aggregate short- and intermediate-term risks do not exceed levels of
concern, and that there is reasonable certainty that no harm will
result.
EPA concludes that there is a reasonable certainty that no harm
will result to infants and children from aggregate exposure to
tefluthrin residues.
5. Special Docket. The complete acute and chronic exposure analyses
(including dietary, non-dietary, drinking water, and residential
exposure, and analysis of exposure to infants and children) used for
risk assessment purposes can be found in the Special Docket for the
FQPA under the title ``Risk Assessment for Extension of Tolerances for
Synthetic Pyrethroids.'' Further explanation regarding EPA's decision
regarding the additional safety factor can also be found in the Special
Docket.
G. Endocrine Disrupter Effects
EPA is required to develop a screening program to determine whether
certain substances (including all pesticides and inerts) ``may have an
effect in humans that is similar to an effect produced by a naturally
occurring estrogen, or such other endocrine effect...'' The Agency is
currently working with interested stakeholders, including other
government agencies, public interest groups, industry and research
scientists in developing a screening and testing program and a priority
setting scheme to implement this program. Congress has allowed 3 years
from the passage of FQPA (August 3, 1999) to implement this program. At
that time, EPA may require further testing of this active ingredient
and end use products for endocrine disrupter effects.
III. Other Considerations
A. Metabolism In Plants and Animals
Plant metabolism studies indicate that tefluthrin per se is not
translocated to plants but is degraded in soil to two principal
metabolites that are capable of being taken up by plants. The
metabolites are the products of the cleavage of the ester to the free
acid (Z)-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-
dimethylcyclopropane carboxylic acid (Metabolite Ia) and to 2,3,5,6-
tetrafluoro-4-hydroxymethylbenzoic acid (Metabolite VI). The Agency
concluded that Metabolite VI need not be regulated.
In animals, dosing with radioactive tefluthrin at level equivalent
to 11 ppm in feed resulted in identifiable residues of tefluthrin and
its metabolites in tissues but at levels below those capable of
detection by proposed enforcement methods.
B. Analytical Enforcement Methodology
Validated enforcement analytical methods are available for
tefluthrin parent (Method PPRAM No. 85/1, The Determination of Residues
of Tefluthrin in Crops and Soil-A Gas-Liquid Chromatographic Method)
and for Metabolite Ia (Method GRAM-028 A Gas Chromatography Method for
the
[[Page 62960]]
Determination of Residues of the Tefluthrin Metabolite PP890 in Crops
of High and Low Moisture Content). The limits of quantitation of these
methods are 0.01 ppm for tefluthrin and 0.05 ppm for Metabolite Ia.
C. Magnitude of Residues
1. Plant commodities-- Field trial studies. No residues were
detected in field trials conducted at maximum label rates and minimum
PHIs. Tolerances were established at the limit of quantitation of the
analytical method (0.06 ppm). The 0.06 ppm tolerances were used to
estimate chronic and acute dietary exposure to potential residues of
tefluthrin.
2. Animal commodities. Studies conducted indicate that no residues
are detected in animal tissues, milk, and eggs and therefore secondary
residues would not be a concern. For that reason, no tolerances have
been established on meat, milk, and eggs. Secondary residues were
therefore not considered in these analyses.
D. International Residue Limits
There are no Codex Maximum Residue Levels established for
tefluthrin. No Canadian MRLs have been established for residues of
tefluthrin on corn commodities. Mexico has established a tolerance for
residues of tefluthrin on corn grain (0.06 ppm) which is in harmony
with the U.S. tolerance.
IV. Conclusion
Therefore, the tolerance is established for combined residues of
tefluthrin and its metabolite in corn, grain, field and pop; corn,
forage and fodder, field, pop and sweet; and corn, fresh (including
sweet K and corn with husk removed (CWHR)) at 0.06 ppm.
V. Objections and Hearing Requests
The new FFDCA section 408(g) provides essentially the same process
for persons to ``object'' to a tolerance regulation issued by EPA under
new section 408(e) and (l)(6) as was provided in the old section 408
and in section 409. However, the period for filing objections is 60
days, rather than 30 days. EPA currently has procedural regulations
which govern the submission of objections and hearing requests. These
regulations will require some modification to reflect the new law.
However, until those modifications can be made, EPA will continue to
use those procedural regulations with appropriate adjustments to
reflect the new law.
Any person may, by January 26, 1998 file written objections to any
aspect of this regulation and may also request a hearing on those
objections. Objections and hearing requests must be filed with the
Hearing Clerk, at the address given above (40 CFR 178.20). A copy of
the objections and/or hearing requests filed with the Hearing Clerk
should be submitted to the OPP docket for this rulemaking. The
objections submitted must specify the provisions of the regulation
deemed objectionable and the grounds for the objections (40 CFR
178.25). Each objection must be accompanied by the fee prescribed by 40
CFR 180.33(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.
VI. Public Docket
EPA has established a record for this rulemaking under docket
control number [OPP-300576] (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 1132 of the Public Information and Records
Integrity Branch, Information Resources and Services Division (7502C),
Office of Pesticide Programs, Environmental Protection Agency, Crystal
Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
Electronic comments may be sent directly to EPA at:
[email protected].
Electronic comments must be submitted as an ASCII file avoiding the
use of special characters and any form of encryption.
The official record for this rulemaking, as well as the public
version, as described above will be kept in paper form. Accordingly,
EPA will transfer any copies of objections and hearing requests
received electronically into printed, paper form as they are received
and will place the paper copies in the official rulemaking record which
will also include all comments submitted directly in writing. The
official rulemaking record is the paper record maintained at the
Virginia address in ADDRESSES at the beginning of this document.
VII. Regulatory Assessment Requirements
This final rule establishes 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). 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 on the basis of a petition under FFDCA section 408(d), 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,
[[Page 62961]]
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.
VIII. Submission to Congress and the General Accounting Office
Under 5 U.S.C. 801(a)(1)(A), as added by the Small Business
Regulatory Enforcement Fairness Act of 1996, the Agency has submitted 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 General Accounting Office prior to publication of this rule in
today's Federal Register. This 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: November 14, 1997.
James Jones,
Acting 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. Section 180.440 is revised to read as follows:
Sec. 180.440 Tefluthrin; tolerances for residues.
(a) General. Tolerances are established for the combined residues
of the insecticide tefluthrin (2,3,5,6 tetrafluroro-4-
methylphenyl)methyl-(1 alpha, 3 alpha)-(Z)-()-3(2-chloro-
3,3,3-trifluoro-1-propenyl)-2,2-diemthylcyclopropanecarboxylate) and
its metabolite (Z)-3-(2-chloro-3,3,3-trifluroro-1-propenyl)-2,2-
dimethylcyclopropanecarboxylic acid in or on the following commodities:
------------------------------------------------------------------------
Parts per
Commodity million
------------------------------------------------------------------------
Corn, field, fodder and forage, pop and sweet.............. 0.06
Corn, fresh (including sweet K and corn with husk removed
(CWHR).................................................... 0.06
Corn, field, grain and pop................................. 0.06
------------------------------------------------------------------------
(b) Section 18 emergency exemptions. [Reserved]
(c) Tolerances with regional registrations. [Reserved]
(d) Indirect or inadvertent residues. [Reserved]
[FR Doc. 97-30946 Filed 11-25-97; 8:45 am]
BILLING CODE 6560-50-F