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Lambda-cyhalothrin (Zeneca). July 9, 1997. Time-Limited Pesticide Tolerance for Rice. Final Rule. Federal Register.
http://frwebgate4.access.gpo.gov/cgi-bin/waisgate.cgi?WAISdocID=13051730204+0+0+0&WAISaction=retrieve
[Federal Register: July 9, 1997 (Volume 62, Number 131)]
[Rules and Regulations]
[Page 36665-36671]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09jy97-10]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300509; FRL-5728-8]
RIN 2070-AB78
Lambda-cyhalothrin; Time-Limited Pesticide Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation establishes a time-limited tolerance for the
combined residues of lambda-cyhalothrin and its epimer in or on rice.
The names for lambda-cyhalothrin and its epimer are as follows: Lambda-
cyhalothrin, a 1:1 mixture of (S)-alpha-cyano-3-phenoxybenzyl-(Z)-
(1R,3R)-3-(2-chloro-3,3,3-trifluoroprop-1-enyl) -2,2-
dimethylcyclopropanecarboxylate and (R)-alpha-cyano-3-phenoxybenzyl-
(Z)-(1S,3S) -3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-
dimethylcyclopropanecarboxylate and Epimer of lambda-cyhalothrin, a 1:1
mixture of (S)-alpha-cyano-3-phenoxybenzyl-(Z)-(1S,3S)-3-(2-chloro-
3,3,3- trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylate and
(R)-alpha-cyano-3-phenoxybenzyl-(Z)-(1R,3R)-3-(2-chloro-3,3,3-
trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylate. The Zeneca
Ag Products requested this tolerance under the Federal Food, Drug and
Cosmetic Act (FFDCA), as amended by the Food Quality Protection Act of
1966 (Pub. L. 104-170). The tolerance will expire on November 15, 1997.
DATES: This regulation is effective July 9, 1997. Objections and
requests for hearings must be received by EPA on or before September 8,
1997.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [OPP-300509], 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 withthe Hearing Clerk identified by the docket
control number, [OPP-300509], must also be submitted to: Public
Information and Records Integrity Branch, Information Resources and
Services Division (7506C), 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: opp-docket@epamail.epa.gov. Copies of objections and
hearing requests must be submitted as an ASCII file avoiding the use of
special characters and any form of encryption. Copies of objections and
hearing requests will also be accepted on disks in WordPerfect 5.1 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-300509]. 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: George T. LaRocca, Product
Manager (PM) 13, Registration Division (7505C), Office of Pesticide
Programs, Environmental Protection Agency, 401 M St., SW., Washington,
DC 20460. Office location, telephone number, and e-mail address:
Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA, (703) 308-
6100, e-mail: larocca.george@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: In the Federal Register of February 19, 1997
(62 FR 7454; FRL-5585-5), 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 petition (PP 6F4769) for tolerance
by Zeneca Ag Products, 1800 Concord Pike, P.O. 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 petition requested that 40 CFR 180.438 be amended by
establishing a tolerance for combined residues of the insecticide
lambda-cyhalothrin and its epimer (CAS NO. 91465-08-6; EPA Chemical NO.
128867), in or on rice grain at 1.0 parts per million (ppm), rice straw
at 1.75 ppm, rice hulls at 5.0 ppm. Subsequent to this filing EPA
recommended that the tolerance on rice straw be rounded off to 1.8 ppm.
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
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).
[[Page 36666]]
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 groundwater
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 ``worstcase'' 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 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 lambda-
cyhalothrin and its epimer, and to make a determination on aggregate
exposure, consistent with section 408(b)(2), for a time-limited
tolerance for combined residues of lambda-cyhalothrin and its epimer on
rice grain at 1.0 ppm, rice straw at 1.8 ppm, and rice hulls at 5.0
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
[[Page 36667]]
concerning the variability of the sensitivities of major identifiable
subgroups of consumers, including infants and children. The nature of
the toxic effects caused by lambda-cyhalothrin are discussed below.
1. Acute toxicity. Acute toxicity studies with the technical
gradeof the active ingredient lambda-cyahothrin: oral LD<INF>50</INF>
in the rat of 79 mg/kg (males) and 56 mg/kg (females), dermal
LD<INF>50</INF> in the rat of 632 mg/kg (males) and 696 mg/kg females,
primary eye irritation study showed mild irritation and primary dermal
irritation study showed no irritation.
2. Genotoxicity. The following genotoxicity tests were all
negative: a gene mutation assay (Ames), a mouse micronucleus assay, an
in-vitro cytogenetics assay, and a gene mutation study in mouse
lymphoma cells.
3. A three-generation reproduction study in rats fed diets
containing 0, 10, 30, and 100 ppm with no developmental toxicity
observed at 100 ppm, the highest dose tested. The maternal NOEL and
LOEL (lowest observed effect level) for the study are established at 30
(1.5 mg/kg/day) and 100 ppm (5 mg/kg/day), respectively, based upon
decreased parental body weight gain. The reproductive NOEL and LOEL are
established at 30 (1.5 mg/kg/day) and 100 ppm (5 mg/kg/day),
respectively, based on decreased pup weight gain during weaning.
4. A developmental toxicity study in rats given gavage doses of 0,
5, 10, and 15 mg/kg/day with no developmental toxicity observed under
the conditions of the study. The developmental NOEL is greater than 15
mg/kg/day, the highest dose tested. The maternal NOEL and LOEL are
established at 10 and 15 mg/kg/day, respectively, based on reduced body
weight gain.
5. A developmental toxicity study in rabbits given gavage doses of
0, 3, 10, and 30 mg/kg/day with no developmental toxicity observed
under the conditions of the study. The maternal NOEL and LOEL are
established at 10 and 30 mg/kg/day, respectively based on decreased
body weight gain. The developmental NOEL is greater than 30 mg/kg/day,
the highest dose tested.
6. A 90-day feeding study in rats fed doses of 0, 10, 50 and 250
ppm with a NOEL of 50 ppm and a LOEL of 250 ppm based on body weight
gain reduction.
7. A 21-day study in rabbits exposed dermally to doses of 0, 10,
100, and 1,000 mg/kg/day, 6 hours/day, 5 days/week with a systemic NOEL
>1,000 mg/kg/kg. There were no clinical signs of systemic toxicity at
any dose level tested.
8. A 12-month feeding study in dogs fed dose (by capsule) levels of
0, 0.1, 0.5, 3.5 mg/kg/day with a NOEL of 0.1 mg/kg/day. The LOEL for
this study is established at 0.5 mg/kg/day based upon clinical signs of
neurotoxicity.
9. A 24-month chronic feeding/carcinogenicity study with rats fed
diets containing 0, 10, 50, and 250 ppm. The NOEL was established at 50
ppm and LOEL at 250 ppm based on reduced body weight gain. There were
no carcinogenic effects observed under the conditions of the study.
10. A carcinogenicity study in mice fed dose levels of 0, 20, 100,
or 500 ppm (0, 3, 15, or 75 mg/kg/day) in the diet for 2 years. A
systemic NOEL was established at 100 ppm and systemic LOEL at 500 ppm
based on decreased body weight gain in males throughout the study at
500 ppm. The EPA has classified lambda-cyhalothrin as a Group D
carcinogen (not classifiable due to an equivocal finding in this
study). No treatment-related carcinogenic effects were observed under
the conditions of the study.
11. Animal metabolism. Metabolism studies in rats demonstrated that
distribution patterns and excretion rates in multiple oral dose studies
are similar to single-dose studies. Accumulation of unchanged compound
in fat upon chronic administration with slow elimination. Otherwise,
lambda-cyhalothrin was rapidly metabolized and excreted. The metabolism
of lambda-cyhalothrin in livestock has been studied in the goat,
chicken, and cow. Unchanged lambda-cyhalothrin is the major residue
component of toxicological concern in meat and milk.
B. Toxicological Endpoints
1. Acute toxicity. No endpoint was selected by EPA to assess acute
dietary risk. EPA determined that this risk assessment was not required
since there was no acute dietary end point of concern.
2. Short - and intermediate - term toxicity. As part of the hazard
assessment process, EPA reviews the available toxicological database to
determine the endpoints of concern for non-dietary exposure. For short-
and intermediate-term inhalation margin of exposure (MOE) calculations,
EPA used a NOEL of 0.3 <greek-m>g/l (0.05 mg/kg/day) from the 21-day
inhalation toxicity study in rats. The LEL of 3.3 <greek-m>g/l was
based on decreased body weight gains and clinical signs of toxicity
including paw flicking, tail erections and tiptoe gait. EPA did not
select an end point for short and intermediate term dermal exposure
since in the 21-day dermal toxicity study, the NOEL was >1,000 mg/kg/
day (limit dose).
3. Toxicity endpoint for dietary exposure--Chronic toxicity. EPA
has established the reference dose (RfD) for lambda-cyhalothrin at
0.001 milligrams/kilogram/day (mg/kg/day). This RfD is based on on a 1-
year oral study in dogs with a NOEL of 0.1 mg/kg/day and an uncertainty
factor (UF) of 100. The LEL of 0.5 mg/kg/day was based on clinical
signs of neurotoxicity (convulsions, ataxia, muscle tremors) and a
slight increase in liquid feces.
4. Carcinogenicity. Based on the available carcinogenicity studies
in two rodent species, lambda-cyhalothrin has been classified as a
Group ``D'' chemical, ``not classifiable as to human carcinogenicity.''
Although lambda-cyhalothrin was not shown to be carcinogenic in either
the mouse or rat, the EPA Hazard Evaluation Division (HED) RfD/PEER
review committee based the ``D'' classification on: (1) lambda-
cyhalothrin was not tested at adequate dose levels for carcinogenicity
testing in the mouse, and (2) the equivocal nature of the findings with
regard to the incidence of mammary adenocarcinomas. No additional
cancer studies are being required at this time.
C. Exposures and Risks
1. From food and feed uses. The primary source of human exposure to
lambda-cyhalothrin will be from ingestion of both raw and processed
food commodities treated with lambda-cyhalothrin. Time-limited
tolerances have been established in 40 CFR 180.438, 40 CFR 185.3765 and
40 CFR 186.3765 for combined residues of lambda-cyhalothrin and its
epimer in or on a variety of food commodities. Risk assessments were
conducted by EPA to assess dietary exposures and risks from lambda-
cyhalothrin as follows:
i. Acute exposure and risk. An acute risk assessment was not
conducted because the Agency has not identified an acute dietary
endpoint of concern for lambda-cyhalothrin.
ii. Chronic exposure and risk. For purposes of assessing the
potential chronic dietary and risk exposure estimates (DRES) for
lambda-cyhalothrin on rice, EPA estimated chronic dietary exposure
based on anticipated residues and percent crop treated (7% for rice)
for several, but not all, commodities. The existing lambda-cyhalothrin
tolerances plus the proposed rice use resulted in an Anticipated
Residue Contribution (ARC) that is equivalent to the following
percentages of the RfD:
[[Page 36668]]
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Percent of the RfD
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U.S. Population........................... 22%
Nursing Infants (<1 year old)............. 25%
Non-Nursing Infants (<1 year old)......... 70%
Children (1-6 years old).................. 50%
Children (7-12 years old)................. 33%
Hispanics................................. 24%
Non-hispanic Others....................... 27%
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The subgroups listed above are: (1) the U.S. population (48
states); (2) those for infants and children; and, (3) the other
subgroups for which the percentage of the RfD occupied is greater than
that occupied by the subgroup U.S population (48 states). As indicated
above the proposed lambda-cyhalothrin tolerances result in an ARC that
is up to 70% of the RfD for the most sensitive subpopulation (non-
nursing infants (<1 year old)). The general population is 22 percent of
the RfD.
Section 408(b)(2)(F) allows the Agency too 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.
Percent of crop treated estimates are derived from federal and
market survey data. EPA considers these data reliable. Typically a
range of estimates are supplied and the upper end of this range is used
for the exposure assessment. By using this upper end estimate of
percent crop treated, EPA is reasonably certain that exposure is not
underestimated 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
EPA to be reasonably certain that no regional population is exposed to
residue levels higher than those estimated by EPA. EPA has made these
findings when appropriate with respect to the proposed tolerance of
lambda-cyhalothrin on rice. EPA has not provided for periodic
reevaluation of the data on percent crop treated for lambda-cyhalothrin
because this tolerance has a time-limitation.
2. From drinking water. Because the Agency lacks sufficient water-
related exposure data to complete a comprehensive drinking water risk
assessment for many pesticides, EPA has commenced and nearly completed
a process to identify a reasonable yet conservative bounding figure for
the potential contribution of water-related exposure to the aggregate
risk posed by a pesticide. In developing the bounding figure, EPA
estimated residue levels in water for a number of specific pesticides
using various data sources. The Agency then applied the estimated
residue levels, in conjunction with appropriate toxicological endpoints
(RfD's or acute dietary NOEL's) and assumptions about body weight and
consumption, to calculate, for each pesticide, the increment of
aggregate risk contributed by consumption of contaminated water. While
EPA has not yet pinpointed the appropriate bounding figure for exposure
from contaminated water, the ranges the Agency is continuing to examine
are all below the level that would cause lambda-cyhalothrin to exceed
the RfD if the tolerance being considered in this document were
granted. The Agency has therefore concluded that the potential
exposures associated with lambda-cyhalothrin in water, even at the
higher levels the Agency is considering as a conservative upper bound,
would not prevent the Agency from determining that there is a
reasonable certainty of no harm if the tolerance is granted.
3. From non-dietary exposure. Lambda-cyhalothrin is currently
registered for use on the following residential non-food sites: general
indoor/outdoor pest control (crack/crevice/spot), termiticide,
ornamental plants and lawns around homes, parks, recreation areas and
athletic fields, and golf course turf. Application of this pesticide in
and around these sites is mainly limited to commercial applicators.
EPA lacks sufficient residential-related exposure data to complete
a comprehensive residential risk assessment for many pesticides,
including lambda-cyhalothrin. However, due to the following facts: (1)
that lambda-cyhalothrin has a low vapor pressure (2 x 10-
<SUP>10</SUP> torr); (2) there are no acute toxicity endpoints
identified; (3) no short- or intermediate-term dermal toxicity endpoint
was identified; (4) high worker inhalation MOEs (which ranged from
1,000 to 6,800); and (5) the percentage of the RfD that is occupied by
the pending and registered uses of this chemical is below 100; EPA has
concluded that non-dietary, non-occupational uses of lambda-cyhalothrin
would not pose a risk that exceeds EPA's level of concern.
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).
[[Page 36669]]
Although lambda-cyhalothrin is structurally similar to other
members of the synthetic pyrethroid class of insecticides, EPA does not
have, at this time, available data to determine whether lambda-
cyhalothrin 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, lambda-cyhalothrin does not
appear to have a toxic metabolite produced by other substances. For the
purposes of this tolerance action, therefore, EPA has not assumed that
lambda-cyhalothrin has a common mechanism of toxicity with other
substances.
C. Aggregate Risks and Determination of Safety for U.S. Population
1. Acute risks. As indicated above, a risk assessment was not
conducted because EPA has not identified an acute toxicity dietary
endpoint for lambda-cyhalothrin.
2. Chronic risk. Using the exposure assumptions and risks described
above, and taking into account the completeness and reliability of the
toxicity data, EPA has concluded that dietary exposure to lambda-
cyhalothrin will utilize 22% of the RfD for the U.S. population. EPA
generally has no concern for exposures below 100% of the RfD because
the RfD represents the level at or below which daily aggregate dietary
exposure over a lifetime will not pose appreciable risks to human
health. Despite the potential for exposure to lambda-cyhalothrin in
drinking water and via residential uses, EPA does not expect the
aggregate exposure to exceed 100% of the RfD. EPA concludes that there
is a reasonable certainty that no harm will result from aggregate
exposure to lambda-cyhalothrin residues.
D. Aggregate Cancer Risk for U.S. Population
Lambda-cyhalothrin has been classified by EPA as a Group ``D''
chemical, ``not classifiable as to human carcinogenicity''. Therefore,
this risk assessment was not conducted.
E. Aggregate Risks and Determination of Safety for Infants and Children
In assessing the potential for additional sensitivity of infants
and children to residues of lambda-cyhalothrin, EPA considered data
from developmental toxicity studies in rats and rabbits and a 3-
generation reproductive toxicity study in rats. The developmental
toxicity studies are designed to evaluate adverse effects on the
developing organism resulting from maternal pesticide exposure during
prenatal development. Reproduction studies provide information relating
to pre- and post-natal effects from exposure to the pesticide,
information on the reproductive capability of mating animals, and data
on systemic toxicity.
FFDCA section 408 provides that EPA shall apply an additional
tenfold margin of safety for infants and children in the case of
threshold effects to account for pre-and post-natal toxicity and the
completeness of the database unless EPA determines that a different
margin of safety will be safe for infants and children. Margins of
safety are incorporated into EPA risk assessments either directly
through use of a margin of exposure analysis or through using
uncertainty (safety) factors in calculating a dose level that poses no
appreciable risk to humans. In either case, EPA generally defines the
level of appreciable risk as exposure that is greater than 1/100 of the
no observed effect level (NOEL) in the animal study appropriate to the
particular risk assessment. This 100-fold uncertainty (safety) factor
is designed to account for inter-species extrapolation and intra-
species variability. EPA believes that reliable data support using the
standard 100-fold 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 factor.
1. Developmental toxicity studies. a. From the developmental
toxicity study in rats, the maternal (systemic) NOEL was 10 mg/kg/day.
The maternal LEL of 15 mg/kg/day was based on decreased body weight
gain and decreased food consumption. The developmental (fetal) NOEL was
>15 mg/kg/day at the highest dose tested (HDT).
b. From the developmental toxicity study in rabbits, the maternal
(systemic) NOEL was 10 mg/kg/day. The maternal LEL of 30 mg/kg/day was
based on decreased body weight gain. The developmental (fetal) NOEL was
<gr-thn-eq>30 mg/kg/day (HDT).
2. Reproductive toxicity studies. From the 3-generation
reproductive toxicity study in rats, both the parental (systemic) and
reproductive (pup) NOEL's were 1.5 mg/kg/day. Both the parental
(systemic) and reproductive (pup) LEL's were 5 mg/kg/day. They were
based on a significant decrease in parental body weight (systemic) or a
significant decrease in pup body weight.
3. Pre- and post-natal sensitivity.The toxicology data base for
lambda-cyhalothrin is complete with respect to current toxicological
data requirements. There are no pre- or post-natal toxicity concerns
for infants and children, based on the results of the rat and rabbit
developmental toxicity studies and the 3-generation reproductive
toxicity study in rats.
Based on the above, EPA concludes that reliable data support the
use of the standard 100-fold margin of uncertainty factor and that an
additional uncertainty factor is not warranted at this time.
4. Acute risk. This risk assessment was not conducted because
EPAhas not identified an acute toxicity dietary endpoint of concern for
lambda-cyhalothrin.
5. Chronic risk. Using the exposure assumptions described above,
EPA has concluded that the percent of the RfD that will be utilized by
dietary exposure to residues of lambda-cyhalothrin ranges from 25% for
nursing infants less than one year old, up to 70% for non-nursing
infants less than 1 year old. Despite the potential for exposure to
lambda-cyhalothrin in drinking water and via residential uses, EPA does
not expect the aggregate exposure to exceed 100% of the RfD. Therefore,
taking into account the completeness and reliability of the toxicity
data and the conservative exposure assessment, EPA concludes that there
is a reasonable certainty that no harm will result to infants and
children from aggregate exposure to lambda-cyhalothrin residues.
III. Other Considerations
A. Endocrine 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.
B. Metabolism In Plants and Animals
The metabolism of lambda-cyhalothrin in plants and animals is
[[Page 36670]]
adequately understood for the purpose of this tolerance. EPA has
determined that plant and animal metabolites do not need to appear in
the tolerance expression at this time. The residues to be regulated are
lambda-cyhalothrin and its epimer as specified in 40 CFR 180.438.
C. Magnitude of Residues
Field residue data reflecting the application of lambda-cyhalothrin
to rice are acceptable in quantity and quality and location in support
of the proposed tolerances on rice grain, rice hulls, and rice straw.
The existing tolerances for meat, milk, poultry and eggs are based on
the transfer of residues from a worse-case diet consisting of various
animal feed items containing residues of lambda-cyhalothrin and its
epimer. No increase in the dietary burden of poultry and ruminants is
expected from use on rice. Therefore, any secondary residues that might
result in milk, meat, poultry and eggs would be covered by the existing
tolerances on these commodities.
D. Analytical Enforcement Methodology
There is a practical analytical method available for determination
of residues of lambda-cyhalothrin and its epimer. Adequate enforcement
methodology (gas chromatography/electron capture detector) for plant
and animal commodities is available to enforce the tolerances. EPA will
provide information on this method to FDA. In the interim, the
analytical method is available to anyone who is interested in pesticide
residue enforcement from: By mail, Calvin Furlow, Public Information
and Records Integrity Branch, Information Resources and Services
Division (7506C), Office of Pesticide Programs, Environmental
Protection Agency, 401 M St. SW., Washington, DC 20460. Office location
and telephone number: Crystal Mall #2, Rm 1128, 1921 Jefferson Davis
Hwy., Arlington, VA 22202, 703-305-5805.
E. International Residue Limits
There are no Codex, Canadian, or Mexican maximum residue limits
(MRLs) for residues of lambda-cyhalothrin and its epimer in/on rice.
Therefore, international harmonization is not an issue for this
tolerance.
F. Rotational Crop Restrictions
Studies submitted in support of lambda-cyhalothrin registration
show that significant residues (<0.01 ppm) will not be present in crops
rotated 30 days after application of parent lambda-cyhalothrin. No
additional rotational crop data are needed to support current
registered application rates.
IV. Conclusion
A time limited tolerance is being established for lambda-
cyhalothrin and its epimer, in/or on rice grain at 1.0 ppm, rice straw
at 1.8 ppm, and rice hulls at 5.0 ppm. Tolerances are time limited to
allow development and review of drinking water and cumulative exposure
data. Based upon the information and data considered EPA concludes that
the proposed time limited tolerances will be safe. Therefore the
tolerances are established as set forth in this document.
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 September 8, 1997, 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
Confidential Business Information (CBI). Information so marked will not
be disclosed except in accordance with procedures set forth in 40 CFR
part 2. A copy of the information that does not contain CBI must be
submitted for inclusion in the public record. Information not marked
confidential may be disclosed publicly by EPA without prior notice.
VI. Public Docket
EPA has established a record for this rulemaking under docket
control number [OPP-300509] (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 (7506C),
Office of Pesticide Programs, Environmental Protection Agency, Crystal
Mall #2, 1921 Jefferson Davis Highway, Arlington, VA.
Electronic comments may be sent directly to EPA at:
opp-docket@epamail.epa.gov.
Electronic comments must be submitted as an ASCII file avoiding the
use of special characters and any form of encryption.
The official record for this rulemaking, as well as the public
version, as described above will be kept in paper form. Accordingly,
EPA will transfer any copies of objections and hearing requests
received electronically into printed, paper form as they are received
and will place the paper copies in the official rulemaking record which
will also include all comments submitted directly in writing. The
official rulemaking record is the paper record maintained at the
Virginia address in ``ADDRESSES'' at the beginning of this document.
VII. Regulatory Assessment Requirements
This final rule establishes a time limited tolerance under FFDCA
section 408(d) in response to a petition
[[Page 36671]]
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 time limited tolerance in this final rule, do not require the
issuance of a proposed rule, the requirements of the Regulatory
Flexibility Act (RFA) (5 U.S.C. 601 et seq.) do not apply.
Nevertheless, the Agency has previously assessed whether establishing
tolerances, exemptions from tolerances, raising tolerance levels or
expanding exemptions might adversely impact small entities and
concluded, as a generic matter, that there is no adverse economic
impact. The factual basis for the Agency's generic certification for
tolerance actions published on May 4, 1981 (46 FR 24950) and was
provided to the Chief Counsel for Advocacy of the Small Business
Administration.
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: June 25, 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 180.438 is revised to read as follows:
Sec. 180.438 Lambda-cyhalothrin; tolerances for residues.
(a) General. Time limited tolerances are established for residues
of the insecticide lambda-cyhalothrin, a 1:1 mixture of (S)-alpha-
cyano-3-phenoxybenzyl-(Z)-(1R,3R)-3-(2-chloro-3,3,3-trifluoroprop-1-
enyl) -2,2- dimethylcyclopropanecarboxylate and (R)-alpha-cyano-3-
phenoxybenzyl-(Z)-(1S,3S)-3-(2-chloro-3,3,3-trifluoroprop-1-enyl)-2,2-
dimethylcyclopropanecarboxylate and the Epimer of lambda-cyhalothrin, a
1:1 mixture of (S)-alpha-cyano-3-phenoxybenzyl-(Z)-(1S,3S)-3-(2-chloro-
3,3,3- trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylate and
(R)-alpha-cyano-3-phenoxybenzyl-(Z)-(1R,3R)-3-(2-chloro-3,3,3-
trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylate on plants, as
indicated in the following table. The tolerance will expire on the date
specified in the following table.
------------------------------------------------------------------------
Expiration/
Commodity Parts per million Revocation Date
------------------------------------------------------------------------
Rice grain...................... 1.0 November 15, 1997
Rice straw...................... 1.8 November 15, 1997
Rice, Hulls..................... 5.0 November 15, 1997
------------------------------------------------------------------------
(b) Section 18 emergency exemptions. [Reserved]
(c) Tolerances with regional registrations. [Reserved]
(d) Indirect or inadvertent residues. [Reserved]
[FR Doc. 97-17591 Filed 7-8-97; 8:45 am]
BILLING CODE 6560-50-F