[Federal Register Volume 62, Number 175 (Wednesday, September 10, 1997)]
[Rules and Regulations]
[Pages 47561-47568]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-23975]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Parts 180, 185 and 186
[OPP-300549; FRL-5743-6]
RIN 2070-AB78
Triadimefon; Pesticide Tolerances for Emergency Exemptions
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation establishes time-limited tolerances for
residues of triadimefon in or on asparagus and in or on artichokes.
This action is in response to EPA's granting of an emergency exemption
under section 18 of the Federal Insecticide, Fungicide, and Rodenticide
Act authorizing use of the pesticide on asparagus and artichokes. This
regulation establishes maximum permissible levels for residues of
triadimefon in these food commodities pursuant to section 408(l)(6) of
the Federal Food, Drug, and Cosmetic Act, as amended by the Food
Quality Protection Act of 1996. These tolerances will expire and are
revoked on September 1, 1999.
DATES: This regulation is effective September 10, 1997. Objections and
requests for hearings must be received by EPA on or before November 10,
1997.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [OPP-300549], 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-300549], 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: [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-300549]. 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: Olga Odiott, 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) 308-9363, e-mail:
[email protected].
SUPPLEMENTARY INFORMATION: EPA, on its own initiative, pursuant to
section 408(e) and (l)(6) of the Federal Food, Drug, and Cosmetic Act
(FFDCA), 21 U.S.C. 346a(e) and (l)(6), is establishing tolerances for
residues of the fungicide triadimefon, in or on asparagus at 0.15 part
per million (ppm), and in or on artichokes at 0.6 ppm. These tolerances
will expire and are revoked on September 1, 1999. EPA will publish a
document in the Federal Register to remove the revoked tolerances from
the Code of Federal Regulations.
I. Background and Statutory Authority
The Food Quality Protection Act of 1996 (FQPA) (Pub. L. 104-170)
was signed into law August 3, 1996. FQPA amends both the Federal Food,
Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 301 et seq., and the Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRA), 7 U.S.C. 136 et
seq. The FQPA amendments went into effect immediately. Among other
things, FQPA amends FFDCA to bring all EPA pesticide tolerance-setting
activities under a new section 408 with a new safety standard and new
procedures. These activities are described below and discussed in
greater detail in the final rule establishing the time-limited
tolerance associated with the emergency exemption for use of
propiconazole on sorghum (61 FR 58135, November 13, 1996)(FRL-5572-9).
New section 408(b)(2)(A)(i) of the FFDCA allows EPA to establish a
tolerance (the legal limit for a pesticide chemical residue in or on a
food) only if EPA determines that the tolerance is ``safe.'' Section
408(b)(2)(A)(ii) defines ``safe'' to mean that ``there is a reasonable
certainty that no harm will result from aggregate exposure to the
pesticide chemical residue, including all anticipated dietary exposures
and all other exposures for which there is reliable information.'' This
includes exposure through drinking water and in residential settings,
but does not include occupational exposure. Section 408(b)(2)(C)
requires EPA to give special consideration to exposure of infants and
children to the pesticide chemical residue in establishing a tolerance
and to ``ensure that there is a reasonable certainty that no harm will
result to infants and children from aggregate exposure to the pesticide
chemical residue....''
Section 18 of FIFRA authorizes EPA to exempt any Federal or State
agency from any provision of FIFRA, if EPA determines that ``emergency
conditions exist which require such exemption.'' This provision was not
amended by FQPA. EPA has established regulations governing such
emergency exemptions in 40 CFR part 166.
Section 408(l)(6) of the FFDCA requires EPA to establish a time-
limited tolerance or exemption from the requirement for a tolerance for
pesticide chemical residues in food that will result from the use of a
pesticide under an emergency exemption granted by EPA under section 18
of FIFRA. Such tolerances can be established without providing notice
or period for public comment.
Because decisions on section 18-related tolerances must proceed
before EPA reaches closure on several policy issues relating to
interpretation and implementation of the FQPA, EPA does not intend for
its actions on such tolerance to set binding precedents for the
application of section 408 and the new safety standard to other
tolerances and exemptions.
[[Page 47562]]
II. Emergency Exemption for Triadimefon on Asparagus and Artichokes
and FFDCA Tolerances
The state of Michigan availed itself of the authority to declare a
crisis exemption to use triadimefon to control the asparagus rust
(Puccinia asparagi). EBDC fungicides are available and are effective
against the asparagus rust but processors in Michigan will not accept
asparagus treated with EBDCs, leaving the Michigan growers with no
alternative for control of the disease. Yield declines of 20 to 50% are
possible without the use of triadimefon.
The state of California stated that powdery mildew, caused by the
fungus Leveillula taurica Lev., is a relatively new disease of
artichokes that was first detected by growers in California during the
summer of 1985. It is now endemic in most artichoke growing districts,
affecting more than 65% of the artichoke acreage. Currently, there are
no registered fungicides or alternative practices available that will
control powdery mildew on artichokes. If triadimefon is not available
for use, yield losses of 30 to 50% are expected. EPA has authorized
under FIFRA section 18 the use of triadimefon on asparagus and
artichokes for control of rust in Michigan and powdery mildew in
California. After having reviewed their submissions, EPA concurs that
emergency conditions exist for these states.
As part of its assessment of this emergency exemption, EPA assessed
the potential risks presented by residues of triadimefon in or on
asparagus and in or on artichokes. In doing so, EPA considered the new
safety standard in FFDCA section 408(b)(2), and EPA decided that the
necessary tolerances under FFDCA section 408(l)(6) would be consistent
with the new safety standard and with FIFRA section 18. Consistent with
the need to move quickly on the emergency exemption in order to address
an urgent non-routine situation and to ensure that the resulting food
is safe and lawful, EPA is issuing these tolerances without notice and
opportunity for public comment under section 408(e), as provided in
section 408(l)(6). Although these tolerances will expire and are
revoked on September 1, 1999, under FFDCA section 408(l)(5), residues
of the pesticide not in excess of the amounts specified in the
tolerance remaining in or on asparagus and in or on artichokes after
that date will not be unlawful, provided the pesticide is applied in a
manner that was lawful under FIFRA. EPA will take action to revoke
these tolerances earlier if any experience with, scientific data on, or
other relevant information on this pesticide indicate that the residues
are not safe.
Because these tolerances are being approved under emergency
conditions EPA has not made any decisions about whether triadimefon
meets EPA's registration requirements for use on asparagus and
artichokes or whether permanent tolerances for these uses would be
appropriate. Under these circumstances, EPA does not believe that these
tolerances serves as a basis for registration of triadimefon by a State
for special local needs under FIFRA section 24(c). Nor do these
tolerances serve as the basis for any State other than Michigan and
California to use this pesticide on these crops under section 18 of
FIFRA without following all provisions of section 18 as identified in
40 CFR part 166. For additional information regarding the emergency
exemption for triadimefon, contact the Agency's Registration Division
at the address provided above.
III. Risk Assessment and Statutory Findings
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 percent 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.
[[Page 47563]]
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 ``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 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.
Percent of crop treated estimates are derived from federal and
private market survey data. Typically, a range of estimates are
supplied and the upper end of this range is assumed for the exposure
assessment. By using this upper end estimate of percent of crop
treated, the Agency is reasonably certain that exposure is not
understated for any significant subpopulation group. 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, to pesticide residues. For this
pesticide, the most highly exposed population subgroup (non-nursing
infants < 1 year old) was not regionally based.
IV. 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
triadimefon and to make a determination on aggregate exposure,
consistent with section 408(b)(2), for a time-limited tolerances for
residues of triadimefon in or on asparagus at 0.15 ppm and in or on
artichokes at 0.6 ppm. EPA's assessment of the dietary exposures and
risks associated with establishing these tolerances follows.
A. Toxicological Profile
EPA has evaluated the available toxicity data and considered its
validity, completeness, and reliability as well as the relationship of
the results of the studies to human risk. EPA has also considered
available information concerning the variability of the sensitivities
of major identifiable subgroups of consumers, including infants and
children. The nature of the toxic effects caused by triadimefon are
discussed below. Triadimenol is a metabolite of triadimefon and is also
an active ingredient in pesticide products (ex. Baytan). Toxicological
endpoints for triadimefon and triadimenol are presented below.
1. Acute toxicity. The NOEL of 20 mg/kg/day from a rabbit
developmental study was selected for assessing acute dietary risk from
residues of triadimefon. The risk assessment will evaluate acute
dietary risks for females 13+ years old.
The Agency has determined that an acute dietary risk assessment is
not required for triadimenol. This decision was based on the lack of
developmental effects at a maternally toxic dose of triadimenol in a
rabbit developmental study.
2. Short - and intermediate - term toxicity. The Agency determined
that the NOEL of 20 mg/kg/day from the developmental toxicity study in
rabbits should be used to assess risks from short and intermediate-term
exposures to residues of triadimefon.
The Agency determined that the NOEL of 250 mg/kg/day (highest dose
tested) from a 21-day dermal toxicity study in rabbits should be used
to assess risks from short- and intermediate-term exposures to residues
of triadimenol.
3. Chronic toxicity. EPA has established the RfD for triadimefon at
0.04 milligrams/kilogram/day (mg/kg/day). This RfD is based on a 2-year
dog feeding study. The NOEL for systemic toxicity in dogs of either sex
was 11.4 mg/kg/day and the LOEL was 33.7 mg/kg/day based on decreased
food intake, depression in weight gain, and significantly (p < 0.05)
increased alkaline phosphatase activity in both sexes. An uncertainty
factor (UF) of 300 was applied to account for inter-species
extrapolation (10), intra-species variability (10) and the lack of an
adequate reproductive toxicity study in rats (3).
The RfD for triadimenol was established at 0.038 mg/kg/day. This
RfD is based on 2-year and 6-month
[[Page 47564]]
feeding studies in dogs with a NOEL of 3.75 mg/kg/day and an
uncertainty factor of 100 based on changes in enzyme levels at the LOEL
of 15.0 mg/kg/day.
4. Carcinogenicity. The Agency's Carcinogenicity Peer Review
Committee (CPRC) has classified triadimefon as a Group C (possible
human carcinogen) chemical without a Q1* and recommended
using the RfD approach to assess dietary cancer risk. The
classification was based on an increase in thyroid adenomas in male
rats and an increase in hepatocellular adenomas, with a positive dose-
related trend, in both male and female mice.
The CPRC classified triadimenol as a Group C (possible human
carcinogen) chemical based on liver tumors in female mice. The
Committee recommended using the RfD approach to assess dietary cancer
risk.
B. Exposures and Risks
1. From food and feed uses. Tolerances have been established (40
CFR 180.410) for the combined residues of triadimefon and its
metabolites containing chlorophenoxy and triazole moieties (expressed
as triadimefon), in or on a variety of raw agricultural commodities
ranging from 0.04 ppm in poultry meat to 145 ppm in grass seed
cleanings.
Tolerances have been established (40 CFR 180.450(a)) for the
combined residues of the fungicide triadimenol (KWG-0519,-(4-
chlorophenoxy)--(1,1-dimethylethyl)-1H-1,2,4-triazol-1-
ethanol) and its butanediol metabolite (KWG-1342; 4-(4-chlorophenoxy)-
2,2-dimethyl-4-(1H-1,2,4-triazol-1-yl)-1,3-butanediol), calculated as
triadimenol, in or on various commodities including barley, oats and
wheat grain at 0.05 ppm; barley, oats and wheat forage at 2.5 ppm; and
barley, oats and wheat straw at 0.1 ppm. Tolerances have been
established (40 CFR 180.450(b)) for the combined residues of
triadimenol and its metabolites containing the chlorophenoxy moiety
(calculated as triadimenol) in or on the fat, meat, and meat by-
products of cattle, goats, hogs, horses and sheep at 0.1 ppm; milk at
0.01 ppm; the fat, meat, and meat by-products of poultry at 0.01 ppm;
and eggs at 0.01 ppm. Risk assessments were conducted by EPA to assess
dietary exposures and risks from triadimefon and triadimenol 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 1-day or single exposure. The acute dietary (food only) risk
assessment for triadimefon used tolerance level residues and assumed
100% crop treated. For the population subgroup of concern, females 13+
years old, the resulting high-end exposure estimate of 0.05 mg/kg/day
results in a dietary (food only) MOE of 400. This MOE should be viewed
as a conservative risk estimate. Refinement of the risk assessment
using anticipated residue values and percent crop-treated data would
result in a lower acute dietary exposure estimate.
Acute dietary endpoints were not identified for triadimenol, so
this risk assessment was not conducted.
ii. Chronic exposure and risk. The chronic dietary risk assessment
for triadimefon assumed that 100% of asparagus and artichokes and all
other commodities having established and pending triadimefon tolerances
will contain triadimefon residues and those residues will be at
tolerance level, which result in an overestimate of human dietary
exposure. The existing triadimefon tolerances (published, pending, and
including the necessary Section 18 tolerances) result in a TMRC that is
equivalent to percentages of the RfD that range from 18% for the U.S.
population to 75% for non-nursing infants < 1 year old.
The chronic dietary risk assessment for triadimenol assumed that
all commodities having established and pending triadimenol tolerances
will contain triadimenol residues and those residues will be at the
level of the tolerance, which result in an overestimate of human
dietary exposure. Thus, in making a safety determination for
triadimenol, EPA is taking into account this conservative exposure
assessment. The existing triadimenol tolerances (published and pending)
result in a TMRC that is equivalent to percentages of the RfD that
range from 1% for the U.S. population to 3% for non-nursing infants < 1
year old.
2. From drinking water. Based on available data used in EPA's
assessment of environmental risk, triadimefon and triadimenol are
mobile and have the potential to leach into ground water. There are no
established Maximum Contaminant Levels for residues of triadimefon or
triadimenol in drinking water, and no Health Advisory levels for
triadimefon or triadimenol in drinking water have been established.
According to the ``Pesticides in Groundwater Database'', EPA 734-12-92-
001, Sept 1992, 14 wells in California were sampled for triadimefon
from 1984-1989. No wells had detectable residues. There was no entry
for triadimenol.
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 triadimefon and triadimenol to
exceed the RfD if the tolerances being considered in this document were
granted. The Agency has therefore concluded that the potential
exposures associated with triadimefon and triadimenol 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 tolerances are granted.
3. From non-dietary exposure. Triadimefon is currently registered
for use on non-food sites such as ornamentals and turfgrass.
Triadimenol is currently registered for use on turfgrass. Based on the
nature of the outdoor residential uses, the EPA concludes that chronic
residential exposure scenarios do not exist for triadimefon. Short and/
or intermediate term exposure scenarios may exist. However, the Agency
currently lacks sufficient residential-related exposure data to
complete a comprehensive residential risk assessment for many
pesticides, including triadimefon.
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
[[Page 47565]]
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).
Triadimefon and triadimenol are members of the triazole class of
pesticides. Other members of this class include tebuconazole,
propiconazole, cyproconazole, penconazole, myclobutanil, and
difenoconazole. At this time, the Agency has not made a determination
that triadimefon and other substances that may have a common mode of
toxicity would have cumulative effects, with the exception of
triadimenol. A regulated metabolite of triadimefon, triadimenol is
itself a fungicide active ingredient registered for use on several
crops. In plants, the residue of concern for triadimenol is triadimenol
and its butanediol metabolite. In animal commodities, the residue of
concern for triadimenol is triadimenol and its metabolites containing
the chlorophenoxy moiety.
To estimate the cumulative (triadimefon + triadimenol) aggregate
dietary exposures, estimates for triadimenol on its regulated
commodities were added to estimates for triadimefon.
C. Aggregate Risks and Determination of Safety for U.S. Population
1. Acute risk. For the population subgroup of concern, females 13+
years, the calculated MOE value for triadimefon dietary (food) exposure
is 400. Although there is potential for exposure to triadimefon in
drinking water, the Agency does not expect the aggregate exposure (food
plus water) to exceed the Agency's level of concern.
No acute toxicity endpoints were identified for triadimenol,
therefore an acute aggregate risk assessment was not conducted.
2. Chronic risk. Using the TMRC exposure assumptions described
above, EPA has concluded that aggregate exposure to triadimefon and
triadimenol from food will utilize 19% of the RfD for the U.S.
population. The major identifiable subgroup with the highest aggregate
exposure is non-nursing infants < 1 year old. EPA generally has no
concern for exposures below 100% of the RfD because the RfD represents
the level at or below which daily aggregate dietary exposure over a
lifetime will not pose appreciable risks to human health. Despite the
potential for exposure to triadimefon and triadimenol in drinking water
and from non-dietary, non-occupational exposure, 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 triadimefon and triadimenol 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 the registered uses of fenarimol short and/or intermediate
term exposure scenarios may exist. However, the Agency currently lacks
sufficient residential-related exposure data to complete a
comprehensive residential risk assessment for many pesticides,
including triadimefon.
D. Aggregate Cancer Risk for U.S. Population
The Agency's CPRC recommended the RfD approach for assessment of
dietary cancer risk. Dietary risk concerns due to long-term exposures
to triadimefon and triadimenol residues are adequately addressed by the
aggregate chronic dietary risk assessment.
E. Aggregate Risks and Determination of Safety for Infants and Children
1. Safety factor for infants and children. i. In general. In
assessing the potential for additional sensitivity of infants and
children to residues of triadimefon and triadimenol, 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 maternal pesticide exposure during
gestation. Reproduction studies provide information relating to effects
from exposure to the pesticide on the reproductive capability of mating
animals and data on systemic toxicity.
FFDCA section 408 provides that EPA shall apply an additional
tenfold margin of safety for infants and children in the case of
threshold effects to account for pre-and post-natal toxicity and the
completeness of the database unless EPA determines that a different
margin of safety will be safe for infants and children. Margins of
safety are incorporated into EPA risk assessments either directly
through use of a MOE analysis or through using uncertainty (safety)
factors in calculating a dose level that poses no appreciable risk to
humans. EPA believes that reliable data support using the standard 100-
fold safety factor (for combined inter- and intra-species variability)
and not the additional tenfold safety 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
safety factor.
ii. Developmental toxicity studies-- a. Rats. For triadimefon, the
maternal systemic NOEL was 30 mg/kg/day and the LOEL was 90 mg/kg/day.
Effects seen at the LOEL include statistically significant body weight
gain decrement during gestational days 6-15. The developmental NOEL was
30 mg/kg/day and the developmental LOEL was 90 mg/kg/day, based on the
increased incidence of skeletal variations, unossified and incompletely
ossified hyoid, and full and rudimentary ribs.
For triadimenol, the maternal (systemic) NOEL was 25 mg/kg/day,
based on decreased body weight and food consumption at the LOEL of 125
mg/kg/day. The developmental (fetal) NOEL was 125 mg/kg/day (highest
dose tested (HDT)).
[[Page 47566]]
b. Rabbits. For triadimefon, the maternal (systemic) NOEL was 50
mg/kg/day and the LOEL was 120 mg/kg/day. The maternal LOEL was based
on increased clinical signs such as increased hyperactivity, reddish
discharge, and decreased body weight gain during gestational days 6-10.
The developmental NOEL was 20 mg/kg/day and the LOEL was 50 mg/kg/day,
based on irregular spinous process and incomplete ossification of
various bones.
For triadimenol, the maternal (systemic) NOEL was 8 mg/kg/day,
based on decreased body weight and food consumption at the LOEL of 40
mg/kg/day. The developmental (fetal) NOEL was 40 mg/kg/day, based on
post-implantation loss, decreased fetal body weight, and skeletal
anomalies at the LOEL of 200 mg/kg/day.
iii. Reproductive toxicity study. An acceptable reproductive
toxicity study is not available for triadimefon.
For triadimenol, the maternal (systemic) NOEL from a 2-generation
reproductive toxicity study in rats was 5.0 mg/kg/day. The NOEL was
based on decreased body weight at the LOEL of 25 mg/kg/day. The
developmental (pup) NOEL was 5.0 mg/kg/day, based on decreased body
weight at the LOEL of 25 mg/kg/day. The reproductive NOEL was 25 mg/kg/
day (HDT).
iv. Pre- and post-natal sensitivity. The toxicological data base
for evaluating pre- and post-natal toxicity for triadimefon is not
complete with respect to current data requirements. However, in
calculating the RfD, an uncertainty factor (UF) of 300 was applied to
account for inter-species extrapolation (10), intra-species variability
(10), and the lack of an adequate reproductive toxicity study in rats
(3). The Agency notes that there is approximately a two-fold difference
between the developmental NOEL of 20 mg/kg/day from the rabbit
developmental toxicity study and the NOEL of 11.4 mg/kg/day from the 2-
year dog feeding study which was the basis of the RfD. It is further
noted that in the rabbit developmental toxicity study, the
developmental NOEL of 20 mg/kg/day (on which the MOE calculations for
acute dietary risks are based) is lower than the maternal systemic NOEL
of 50 mg/kg/day from the same rabbit developmental study. The Agency
believes that the additional 3X uncertainty factor, together with the
very conservative assumptions made for the exposure assessment, provide
adequate protection to infants and children from the risks associated
with exposures to triadimefon residues.
The toxicological data base for evaluating pre- and post-natal
toxicity for triadimenol is complete with respect to current 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 2-generation rat reproductive
toxicity study. The rat developmental study had no developmental
effects up to the highest dose tested, which produced maternal
toxicity. The rabbit developmental toxicity study demonstrated maternal
toxicity at a dose at which no developmental toxicity was apparent. In
the rat reproductive toxicity study, the parental and pup effects occur
at the NOELs and LOELs and the same effect (decreased body weight)
occurred in both pups and parental animals.
v. Conclusion. Based on the above considerations and in EPA's best
scientific judgment, the application of a margin of exposure/
uncertainty factor of 300 provides adequate protection for infants and
children from the risks associated with exposures to triadimefon
residues.
The EPA also concludes that, for triadimenol, reliable data support
use of the standard 100-fold margin of exposure/ uncertainty factor and
that an additional margin/factor is not needed to protect infants and
children.
2. Acute risk. For triadimefon, the acute dietary (food only) MOE
was calculated to be 400 for females 13+ years old (accounts for both
maternal and fetal exposure), the population subgroup of concern. This
risk assessment for triadimefon used tolerance level residues and
assumed 100% crop treated. This MOE should be viewed as a conservative
risk estimate; further refinement using anticipated residue values and
percent crop-treated data would result in a lower acute dietary
exposure estimate. The large acute dietary MOE calculated for females
13+ years provides assurance that there is a reasonable certainty of no
harm for both females 13+ years and the pre-natal development of
infants. Despite the potential for exposure to triadimefon in drinking
water, the Agency does not expect the aggregate exposure (food + water)
to exceed the Agency's level of concern for acute dietary exposure.
No acute toxicity endpoints were identified for triadimenol, so an
acute aggregate risk assesment was not conducted.
3. Chronic risk. Using the conservative exposure assumptions
described above, EPA has concluded that aggregate exposure to
triadimefon and triadimenol from food will utilize percentages of the
RfD that range from 28% for children 7-12 years old, up to 78% for non-
nursing infants less than 1 year old. EPA generally has no concern for
exposures below 100% of the RfD because the RfD represents the level at
or below which daily aggregate dietary exposure over a lifetime will
not pose appreciable risks to human health. Despite the potential for
exposure to triadimefon and triadimenol in drinking water and from non-
dietary, non-occupational exposure, 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 to infants and children
from aggregate exposure to triadimefon and triadimenol residues.
4. Short- or intermediate-term risk. Based on the registered uses
of fenarimol short and/or intermediate term exposure scenarios may
exist. However, the Agency currently lacks sufficient residential-
related exposure data to complete a comprehensive residential risk
assessment for many pesticides.
V. Other Considerations
A. Metabolism In Plants and Animals
The nature of triadimefon residues in plants is adequately
understood. The Agency's Metabolism Committee determined that the
residues of concern are triadimefon and its metabolites containing
chlorophenoxy and triazole moieties, expressed as triadimefon. The
nature of triadimefon residues in animals is not germane to these
tolerances as no livestock feed items are involved.
B. Analytical Enforcement Methodology
Adequate enforcement methods (GC/MS) are published in the Pesticide
Analytical Manual, Volume II, Pesticide Reg. Sec. 180.410, as Methods I
and II. In addition, Mobay Method No. 80488 has undergone a successful
method trial and has been validated for determination of triadimefon
and its metabolites relevant to 40 CFR 180.410 on plant commodities.
C. Magnitude of Residues
Regulable residues of triadimefon are not expected to exceed 0.15
ppm in/on asparagus and 0.6 ppm in/on globe artichokes as a result of
these section 18 uses. Secondary residues are not expected in animal
commodities as no feed items are associated with these section 18 uses.
D. International Residue Limits
There are no CODEX, Canadian, or Mexican maximum residue limits
(MRLs) established for residues of
[[Page 47567]]
triadimefon in/on asparagus or in/on artichokes.
VI. Conclusion
Therefore, time-limited tolerances are established for the
regulable residues of triadimefon in asparagus at 0.15 ppm and in
artichokes at 0.6 ppm. In addition, because the FQPA eliminated the
distinctions between processed food, feed and raw agricultural
commodities, OPP is transferring the tolerances for residues of
triadimefon in Secs. 185.800 and 186.800 to the table in paragraph (a)
of Sec. 180.410 and removing the remainder of Secs. 185.800 and
186.800.
VII. Objections and Hearing Requests
The new FFDCA section 408(g) provides essentially the same process
for persons to ``object'' to a tolerance regulation issued by EPA under
new section 408(e) and (l)(6) as was provided in the old section 408
and in section 409. However, the period for filing objections is 60
days, rather than 30 days. EPA currently has procedural regulations
which govern the submission of objections and hearing requests. These
regulations will require some modification to reflect the new law.
However, until those modifications can be made, EPA will continue to
use those procedural regulations with appropriate adjustments to
reflect the new law.
Any person may, by November 10, 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.
VIII. Public Docket
EPA has established a record for this rulemaking under docket
control number [OPP-300549] (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:
[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.
IX. Regulatory Assessment Requirements
This final rule establishes time-limited tolerances under FFDCA
section 408(d l)(6). 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 under FFDCA section 408(l)(6), such as the tolerances in
this final rule, do not require the issuance of a proposed rule, the
requirements of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et
seq.) do not apply. Nevertheless, the Agency has previously assessed
whether establishing tolerances, exemptions from tolerances, raising
tolerance levels or expanding exemptions might adversely impact small
entities and concluded, as a generic matter, that there is no adverse
economic impact. The factual basis for the Agency's generic
certification for tolerance acations published on May 4, 1981 (46 FR
24950), and was provided to the Chief Counsel for Advocacy of the Small
Business Administration.
X. 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).
[[Page 47568]]
List of Subjects
40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
40 CFR Part 185
Environmental protection, Food additives, Pesticides and pests.
40 CFR Part 186
Environmental protection, Animal feeds, Pesticides and pests.
Dated: August 29, 1997.
James Jones,
Acting Director, Registration Division, Office of Pesticide Programs.
Therefore, 40 CFR chapter I is amended as follows:
PART 180--[AMENDED]
1. In part 180:
a. The authority citation for part 180 continues to read as
follows:
Authority: 21 U.S.C. 346a and 371.
b. By amending Sec. 180.410 as follows:
i. By revising the section heading.
ii. By adding a subject heading to paragraph (a).
iii. By revising paragraphs (b) and (c).
iv. By adding and reserving paragraph (d) with a subject heading.
Sec. 180.410 Triadimefon; tolerances for residues.
(a) General . * * *
(b) Section 18 emergency exemptions. Time-limited tolerances are
established for the combined residues of the fungicide triadimefon, 1-
(4-chlorophenoxy)-3,3-dimethyl-1(1H-1,2,4-triazol-1-yl)-2-butanone and
its metabolites containing chlorophenoxy and triazole moieties
(expressed as the fungicide) in connection with use of the pesticide
under the section 18 emergency exemptions granted by EPA. The
tolerances will expire and are revoked on the dates specified in the
following table:
------------------------------------------------------------------------
Parts
Commodity per Expiration/revocation
million date
------------------------------------------------------------------------
Artichokes........................... 0.6 September 1, 1999
Asparagus............................ 0.15 September 1, 1999
Chili peppers........................ 0.5 November 8, 1997
------------------------------------------------------------------------
(c) Tolerances with regional registrations. Tolerances with
regional registration are established for the combined residues of the
fungicide 1-(4-chlorophenoxy)-3,3-dimethyl-1(1H-1,2,4-triazol-l-yl)-2-
butanone and its metabolites containing chlorophenoxy and triazole
moieties (expressed as the fungicide) in or on the following raw
agricultural commodities:
------------------------------------------------------------------------
Parts
Commodity per
million
------------------------------------------------------------------------
Raspberries................................................... 2.0
------------------------------------------------------------------------
(d) Indirect or inadvertent residues. [Reserved]
PART 185--[AMENDED]
2. In part 185:
a. The authority citation for part 185 continues to read as
follows:
Authority: 21 U.S.C. 346a and 348.
Sec. 185.800 [Removed]
b. In Sec. 185.800 by transferring the entries in the table and
alphabetically adding them to the table in paragraph (a) of
Sec. 180.410, and by removing the remainder of Sec. 185.800.
PART 186--[AMENDED]
3. In part 186:
a. The authority citation for part 185 continues to read as
follows:
Authority: 21 U.S.C. 342, 348, and 701.
Sec. 186.800 [Removed]
b. In Sec. 186.800 by transferring the entries in the table and
alphabetically adding them to the table in paragraph (a) of
Sec. 180.410, and by removing the remainder of Sec. 186.800.
[FR Doc. 97-23975 Filed 9-9-97; 8:45 am]
BILLING CODE 6560-50-F