[Federal Register Volume 62, Number 163 (Friday, August 22, 1997)]
[Rules and Regulations]
[Pages 44558-44565]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-22377]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300533; FRL-5738-6]
RIN 2070-AB78
Sethoxydim; Pesticide Tolerances for Emergency Exemptions
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation establishes a time-limited tolerance for
residues of sethoxydim and its metabolites containing the 2-cyclohexen-
1-one moiety in or on horseradish. 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 horseradish in Illinois. This regulation establishes a
maximum permissible level for residues of sethoxydim in this food
commodity pursuant to section 408(l)(6) of the Federal Food, Drug, and
Cosmetic Act, as amended by the Food Quality Protection Act of 1996.
The tolerance will expire and is revoked on September 30, 1998.
DATES: This regulation is effective August 22, 1997. Objections and
requests for hearings must be received by EPA on or before October 21,
1997.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [OPP-300533], 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-300533], 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
[[Page 44559]]
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-300533]. 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: Virginia Dietrich,
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) 308-9359, e-mail:
dietrich.virginia@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: EPA, on its own initiative, pursuant to
section 408(e) and (l)(6) of the Federal Food, Drug, and Cosmetic Act
(FFDCA), 21 U.S.C. 346a(e) and (l)(6), is establishing a tolerance for
residues of the herbicide sethoxydim, in or on horseradish at 4 part
per million (ppm). This tolerance will expire and is revoked on
September 30, 1998. EPA will publish a document in the Federal Register
to remove the revoked tolerance 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.
II. Emergency Exemption for Sethoxydim on Horseradish and FFDCA
Tolerances
Unprecedented flooding events in the horseradish production areas
in Illinois in the last few years have transported seeds and vegetative
propagules to previously uninfested fields. Currently registered
herbicides, as well as cultural practices (mechanical and hand
weeding), do not provide adequate control. Of particular concern was
infestation by Johnsongrass. Johnsongrass causes losses by competing
with the crop thereby reducing yields. Losses were also realized at the
packing houses because of the similarity of horseradish roots to
Johnsongrass rhizomes. After having reviewed the submission, EPA
concurs that emergency conditions exist for this state. EPA has
authorized under FIFRA section 18 the use of sethoxydim on horseradish
for control of grass weeds in Illinois.
As part of its assessment of this emergency exemption, EPA assessed
the potential risks presented by residues of sethoxydim in or on
horseradish. In doing so, EPA considered the new safety standard in
FFDCA section 408(b)(2), and EPA decided that the necessary tolerance
under FFDCA section 408(l)(6) would be consistent with the new safety
standard and with FIFRA section 18. Consistent with the need to move
quickly on the emergency exemption in order to address an urgent non-
routine situation and to ensure that the resulting food is safe and
lawful, EPA is issuing this tolerance without notice and opportunity
for public comment under section 408(e), as provided in section
408(l)(6). Although this tolerance will expire and is revoked on
September 30, 1998, under FFDCA section 408(l)(5), residues of the
pesticide not in excess of the amounts specified in the tolerance
remaining in or on horseradish 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 this tolerance earlier if any
experience with, scientific data on, or other relevant information on
this pesticide indicate that the residues are not safe.
Because this tolerance is being approved under emergency conditions
EPA has not made any decisions about whether sethoxydim meets EPA's
registration requirements for use on horseradish or whether a permanent
tolerance for this use would be appropriate. Under these circumstances,
EPA does not believe that this tolerance serves as a basis for
registration of sethoxydim by a State for special local needs under
FIFRA section 24(c). Nor does this tolerance serve as the basis for any
State other than Illinois to use this pesticide on this crop 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 sethoxydim, contact the Agency's Registration
Division at the address provided above.
[[Page 44560]]
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% 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 ``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
[[Page 44561]]
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 (children from
one to six years 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
sethoxydim and to make a determination on aggregate exposure,
consistent with section 408(b)(2), for a time-limited tolerance for
residues of sethoxydim and its 2-cyclohexen-1-one moiety on horseradish
at 4 ppm. EPA's assessment of the dietary exposures and risks
associated with establishing the tolerance follows.
A. Toxicological Profile
EPA has evaluated the available toxicity data and considered its
validity, completeness, and reliability as well as the relationship of
the results of the studies to human risk. EPA has also considered
available information concerning the variability of the sensitivities
of major identifiable subgroups of consumers, including infants and
children. The nature of the toxic effects caused by sethoxydim are
discussed below.
1. Acute toxicity. 180 mg/kg/day. For acute dietary risk
assessment, the Office of Pesticide Programs selected the developmental
NOEL of 180 mg/kg/day from the developmental study in rats. At the
developmental lowest observed effect level (LOEL) of 650 mg/kg/day,
there were decreased fetal weights, filamentous tail, lack of tail, and
delayed ossification. Acute dietary risk will be evaluated for the
population subgroup of concern, females 13+ years.
2. Short - and intermediate - term toxicity. For short- and
intermediate-term Margin of Exposure (MOE) calculations, the Office of
pesticide Programs concluded that this risk assessment is not required,
based on the lack of any observable effects in a 21-day dermal toxicity
study in rabbits at the limit dose (1000 mg/kg/day) and the observation
of no adverse effects in a developmental toxicity study in rabbits at
400 mg/kg/day, the highest dose tested (HDT).
3. Chronic toxicity. EPA has established the RfD for sethoxydim at
0.09 milligrams/kilogram/day (mg/kg/day). This RfD is based on a 1-year
feeding study in dogs (MRID# 00152669) with a NOEL of 8.86 mg/kg/day
and an uncertainty factor of 100 based on equivocal anemia in male dogs
at the lowest effect level (LEL) of 17.5 mg/kg/day.
4. Carcinogenicity. Sethoxydim has not been classified with concern
to carcinogenicity by the Office of Pesticide Programs. However, no
positive tumor findings have been reported at this time.
B. Exposures and Risks
1. From food and feed uses. Tolerances have been established (40
CFR 180.412) for combined residues of sethoxydim and its metabolites
containing the 2-cyclohexen-1-one moiety (calculated as the herbicide)
in or on a variety of raw agricultural commodities (RACs) at levels
ranging from 0.2 ppm to 50 ppm. Among them are tolerances on several
RACs of the root and tuber vegetables crop group, of which horseradish
is a member: artichoke (3 ppm), carrots (1 ppm), potatoes (4 ppm),
sweet potatoes (4 ppm), and sugar beet roots (1 ppm). Various food (40
CFR 185.2800) and feed (40 CFR 186.2800) additive tolerances are also
established, at levels up to 75 ppm (peanut soapstock). Risk
assessments were conducted by EPA to assess dietary exposures and risks
from sethoxydim as follows:
i. Acute exposure and risk. The acute dietary (food only) risk
assessment used tolerance level residues for all crops with sethoxydim
tolerances and assumed 100% crop-treated. A Margin of Exposure (MOE) of
960 was calculated for females aged 13+ years, the population subgroup
of concern. That acute dietary (food only) MOE should be viewed as a
conservative risk estimate; refinement using percent crop-treated and
anticipated residue levels or Monte Carlo analysis would result in a
lower dietary exposure estimate. Acute dietary risk assessments are
performed for a food-use pesticide if a toxicological study has
indicated the possibility of an effect of concern occurring as a result
of a one day or single exposure.
ii. Chronic exposure and risk. In conducting this chronic dietary
risk assessment, the Office of Pesticide Programs has made very
conservative assumptions which result in a conservative over-estimate
of human dietary exposure; 100% of horseradish and all other
commodities having tolerances for the regulable residue of sethoxydim
will contain residues of same, and at the level of the tolerance.
Refinement using anticipated residue values and percent crop-treated
data would result in a lower chronic dietary exposure estimate.
The existing sethoxydim regulable residue tolerances (published,
pending, and this Section 18 proposed tolerance) result in a
Theoretical Maximum Residue Contribution (TMRC) that is equivalent to
the following percentages of the RfD:
----------------------------------------------------------------------------------------------------------------
Population Subgroup TMRCfood (mg/kg/day) %RfD
----------------------------------------------------------------------------------------------------------------
U.S. population (48 states)......................... 0.033266 37%
Nursing infants..................................... 0.020447 23%
Non-nursing infants (<1 year="" old)...................="" 0.057129="" 63%="" children="" (1-6="" years="" old)............................="" 0.067039="" 74%="" children="" (7-12="" years="" old)...........................="" 0.049618="" 55%="" southern="" region.....................................="" 0.033782="" 38%="" western="" region......................................="" 0.034829="" 39%="" hispanics...........................................="" 0.039524="" 44%="" males="" (13-19="" years="" old).............................="" 0.033837="" 38%="" ----------------------------------------------------------------------------------------------------------------="" [[page="" 44562]]="" 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).="" 2.="" from="" drinking="" water.="" based="" on="" information="" in="" opp="" files,="" sethoxydim="" is="" a="" non-persistent,="" but="" highly="" mobile="" compound="" in="" soil="" and="" water="" environments.="" there="" are="" no="" maximum="" contaminant="" levels="" or="" health="" advisories="" established="" for="" sethoxydim="" residues="" in="" drinking="" water.="" limited="" monitoring="" data="" of="" ground="" water="" and="" surface="" water="" are="" available="" for="" sethoxydim.="" exposure="" estimates="" using="" these="" data="" are="" listed="" below.="" adult="" exposure:="" groundwater="" sethoxydim="" exposure="" (highest="" concentration="" detected="" in="" public="" supply="" wells)="(1">g/L) * (10-3 mg/g)
(70 kg body weight) * (2 L/day) = 2.85 x 10-5 mg/kg/day.
Sethoxydim Exposure (highest concentration detected in ground water) =
(42 g/L) * (10-3 mg/g) (70 kg
body weight) * (2 L/day) = 1.2 x 10-3 mg/kg/day
Children's Exposure: Groundwater
Sethoxydim Exposure (highest concentration detected in public supply
wells) = (1 g/L) * (10-3 mg/g)
(10 kg body weight) * (1 L/day) = 1 x 10-4 mg/kg/day.
Sethoxydim Exposure (highest concentration detected in ground water) =
(42 g/L) * (10-3 mg/g) (10 kg
body weight) * (1 L/day) = 4.2 x 10-3 mg/kg/day
Estimates of Exposure: Surface Water. The highest concentration of
sethoxydim residues detected in a surface water sample was 0.87
g/L. The same calculations as above for ground water were used
to estimate the exposure of adults (2.49 x 10-5 mg/kg/day)
and children (0.9 x 10-4 mg/kg/day) to sethoxydim residues
in surface water.
i. Acute exposure and risk. The Office of Pesticide Programs
calculates a margin of exposure (MOE) to estimate the acute risk for
drinking water, as follows:
Acute MOE = Acute NOEL (mg/kg/day) Exposure (mg/kg/day)
The acute dietary endpoint is based on the developmental NOEL of
180 mg/kg/day from the developmental study in rats. Using the exposure
estimates calculated above, the acute MOEs for adults and children are
calculated to be > 40,000.
Using the surface water exposure estimates calculated above, the acute
MOEs for adults and children are calculated to be > 1.8 million.
ii. Chronic exposure and risk. 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 sethoxydim 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 sethoxydim 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.
Using the surface water exposure estimates calculated above, the
chronic risks are calculated to be < 1%="" of="" the="" rfd="" for="" both="" adults="" and="" children.="" 3.="" from="" non-dietary="" exposure.="" sethoxydim="" is="" currently="" registered="" for="" use="" on="" the="" following="" residential="" non-food="" sites:="" flowering="" plants,="" recreational="" areas,="" and="" buildings/structures="" (non-agricultural="" -="" outdoor).="" these="" residential="" uses="" comprise="" a="" short-="" and="" intermediate-="" term="" exposure="" scenario,="" but="" do="" not="" comprise="" a="" chronic="" exposure="" scenario.="" since="" the="" tesc="" did="" not="" identify="" a="" short-term,="" intermediate-="" term,="" or="" chronic="" toxicity="" non-dietary="" endpoint,="" a="" short-="" and="" intermediate-term="" aggregate="" risk="" assessment="" is="" not="" required="" for="" this="" section="" 18="" action.="" short-="" and="" intermediate-term="" exposure="" and="" risk.="" the="" office="" of="" pesticide="" programs="" determined="" that="" a="" risk="" assessment="" for="" short-="" and="" intermediate="" term="" exposure="" is="" not="" appropriate="" since="" no="" adverse="" effects="" were="" noted="" in="" toxicity="" studies="" conducted="" for="" this="" duration="" of="" exposure="" 4.="" cumulative="" exposure="" to="" substances="" with="" common="" mechanism="" of="" toxicity.="" section="" 408(b)(2)(d)(v)="" requires="" that,="" when="" considering="" whether="" to="" establish,="" modify,="" or="" revoke="" a="" tolerance,="" the="" agency="" consider="" ``available="" information''="" concerning="" the="" cumulative="" effects="" of="" a="" particular="" pesticide's="" residues="" and="" ``other="" substances="" that="" have="" a="" common="" mechanism="" of="" toxicity.''="" the="" agency="" believes="" that="" ``available="" information''="" in="" this="" context="" might="" include="" not="" only="" toxicity,="" chemistry,="" and="" exposure="" data,="" but="" also="" scientific="" policies="" and="" methodologies="" for="" understanding="" common="" mechanisms="" of="" toxicity="" and="" conducting="" cumulative="" risk="" assessments.="" for="" most="" pesticides,="" although="" the="" agency="" has="" some="" information="" in="" its="" files="" that="" may="" turn="" out="" to="" be="" helpful="" in="" eventually="" determining="" whether="" a="" pesticide="" shares="" a="" common="" mechanism="" of="" toxicity="" with="" any="" other="" substances,="" epa="" does="" not="" at="" this="" time="" have="" the="" methodologies="" to="" resolve="" the="" complex="" scientific="" issues="" concerning="" common="" mechanism="" of="" toxicity="" in="" a="" meaningful="" way.="" epa="" has="" begun="" a="" pilot="" process="" to="" study="" this="" issue="" further="" through="" the="" examination="" of="" particular="" classes="" of="" pesticides.="" the="" agency="" hopes="" that="" the="" results="" of="" this="" pilot="" process="" will="" increase="" the="" agency's="" scientific="" understanding="" of="" this="" question="" such="" that="" epa="" will="" be="" able="" to="" develop="" and="" apply="" scientific="" principles="" for="" better="" determining="" which="" chemicals="" have="" a="" common="" mechanism="" of="" toxicity="" and="" evaluating="" the="" cumulative="" effects="" of="" such="" chemicals.="" the="" agency="" anticipates,="" however,="" that="" even="" as="" its="" understanding="" of="" the="" science="" of="" common="" mechanisms="" increases,="" decisions="" on="" specific="" classes="" of="" chemicals="" will="" be="" heavily="" dependent="" on="" chemical="" specific="" data,="" much="" of="" which="" may="" not="" be="" presently="" available.="" although="" at="" present="" the="" agency="" does="" not="" know="" how="" to="" apply="" the="" information="" in="" its="" files="" concerning="" common="" mechanism="" issues="" to="" most="" risk="" assessments,="" there="" are="" pesticides="" as="" to="" which="" the="" common="" mechanism="" issues="" can="" be="" resolved.="" these="" pesticides="" include="" pesticides="" that="" are="" toxicologically="" dissimilar="" to="" existing="" chemical="" substances="" (in="" which="" case="" the="" agency="" can="" conclude="" that="" it="" is="" unlikely="" that="" a="" pesticide="" shares="" a="" common="" mechanism="" of="" activity="" with="" other="" substances)="" and="" pesticides="" that="" produce="" a="" common="" toxic="" metabolite="" (in="" which="" case="" common="" mechanism="" of="" activity="" will="" be="" assumed).="" epa="" does="" not="" have,="" at="" this="" time,="" available="" data="" to="" determine="" whether="" sethoxydim="" 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,="" sethoxydim="" does="" not="" appear="" to="" produce="" [[page="" 44563]]="" a="" toxic="" metabolite="" produced="" by="" other="" substances.="" for="" the="" purposes="" of="" this="" tolerance="" action,="" therefore,="" epa="" has="" not="" assumed="" that="" sethoxydim="" has="" a="" common="" mechanism="" of="" toxicity="" with="" other="" substances.="" c.="" aggregate="" risks="" and="" determination="" of="" safety="" for="" u.s.="" population="" 1.="" acute="" risk.="" the="" aggregate="" (food="" +="" water)="" moe="" value="" is="" and="" is="" 935,="" based="" on="" an="">food of 960 and a conservative
MOEwater of 40,000. This aggregate MOE value does not exceed
the Agency's level of concern for acute dietary exposure.
2. Chronic risk. Using the conservative TMRC exposure assumptions
described above, and taking into account the completeness and
reliability of the toxicity data, EPA has concluded that chronic
aggregate dietary exposure (food + water) to sethoxydim will utilize
38% (37% from food + 1% from water) 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. Residential (outdoor) usage of sethoxydim does
not comprise a chronic exposure scenario. EPA concludes that there is a
reasonable certainty that no harm will result from chronic aggregate
exposure to sethoxydim 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 short- and
intermediate-term exposure scenarios from indoor and outdoor
residential uses. Since the Office of Pesticide Programs did not
identify a short-term, intermediate-term, or chronic toxicity non-
dietary endpoint, a short- and intermediate-term aggregate risk
assessment was not conducted for this duration of exposure.
D. Aggregate Cancer Risk for U.S. Population
Sethoxydim has not been classified by the Agency's Cancer Peer
Review Committee. However, no positive tumor findings have been
reported at this time in the evaluation of the cancer study in mice or
the preliminary evaluation of the rat study.
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 sethoxydim, 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 (usually 100 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. In the developmental
toxicity study in rats, the maternal (systemic) NOEL was 180 mg/kg/day,
based on irregular gait, decreased activity, excessive salivation and
anogenital staining at the LOEL of 650 mg/kg/day. The developmental
(pup) NOEL was 180 mg/kg/day, based on decreased fetal weights,
filamentous tail, lack of tail, and delayed ossification at the LOEL of
650 mg/kg/day.
b. Rabbits. In the developmental toxicity study in rabbits, the
maternal (systemic) NOEL was 320 mg/kg/day, based on a 37% reduction in
body weight gain without significant differences in group mean body
weights and food consumption at the LOEL of 400 mg/kg/ day. The
developmental (pup) NOEL was 400 mg/kg/day (HDT).
iii. Reproductive toxicity study-- Rats. In the 2-generation
reproductive toxicity study in rats, the maternal (systemic) and
reproductive (pup) NOEL was 150 mg/kg/day (HDT). There were
no indications of toxicity, dose-related effects on fertility or
difficult deliveries in either parental generation.
iv. Pre- and post-natal sensitivity. The toxicological data base
for evaluating pre- and post-natal toxicity for sethoxydim is complete
with respect to current data requirements.
The available data indicate that no developmental toxicity was
observed in the rabbit study at the highest dose tested (400 mg/kg/
day). Maternal toxicity was observed in the rabbit at the highest dose
tested, and consisted of significant reductions in body weight gain and
food consumption.
In the developmental study in rats, developmental toxicity was
observed in the presence of significant maternal toxicity at a high
dose level (650 mg/kg/day).
There was no parental or reproductive toxicity observed in a multi-
generation reproductive toxicity study in rats at doses up to 150 mg/
kg/day (HDT).
These data, taken together, suggest minimal concern for
developmental or reproductive toxicity and do not indicate any extra
pre- or post-natal sensitivity. Thus, these data support use of the
standard uncertainty factor of 100. An additional safety factor is not
needed to protect infants and children.
v. Conclusion. These data, taken together, suggest minimal concern
for developmental or reproductive toxicity and do not indicate any
extra pre- or post-natal sensitivity. Thus, these data support use of
the standard uncertainty factor of 100. An additional safety factor is
not needed to protect infants and children.
2. Acute risk. As calculated above, the acute dietary (food +
water) MOE for females 13+ years (accounts for both maternal and fetal
exposure) is 935, based on an MOEfood of 960 and a
conservative MOEwater of 40,000. This dietary MOE does not
exceed the Agency's level of concern. Further, this MOE should be
viewed as a conservative risk estimate; data refinement and the use of
Monte Carlo analysis would result in a lower acute aggregate exposure
estimate. HED concludes that there is a reasonable certainty that no
harm will result to infants and children from acute aggregate exposure
to sethoxydim regulable residue.
3. Chronic risk. Using the conservative exposure assumptions
described above, EPA has calculated that the percentage of the RfD that
will be utilized by dietary (food only) exposure to the sethoxydim
regulable residue ranges from 23% for nursing infants < 1="" year="" old,="" up="" to="" 74%="" for="" children="" 1-6="" years="" old.="" as="" calculated="" above,="" the="" percentage="" of="" the="" rfd="" that="" will="" be="" utilized="" by="" dietary="" (water)="" exposure="" ranges="" from="">< 1="" to="" 5%="" from="" [[page="" 44564]]="" ground="" water="" and=""><1% from="" surface="" water.="" thus,="" the="" chronic="" aggregate="" (food="" +="" water)="" risk="" ranges="" from=""> 24-29% for nursing infants
< 1="" year="" old,="" to=""> 75-80% for children 1-6 years old. It has
been determined by HED that residential uses do not comprise a chronic
exposure scenario, and thus will not contribute to chronic aggregate
risk. 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 sethoxydim 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 sethoxydim residues.
V. Other Considerations
A. Metabolism In Plants and Animals
The nature of the residue in plants and animals is adequately
understood. The residue of concern is the combined residues of
sethoxydim and its metabolites containing the 2-cyclohexen-1-one moiety
(calculated as the herbicide), as specified in 40 CFR 180.412.
B. Analytical Enforcement Methodology
Adequate enforcement methodology (GLC/FPD-S) is available (Method
I, Pesticide Analytical Manual, Vol. II) to enforce the tolerance
expression.
C. Magnitude of Residues
Combined residues of sethoxydim and its regulated metabolites are
not expected to exceed 4 ppm in/on horseradish as a result of this
Section 18 use. A time-limited tolerance should be established for the
regulable residue in/on horseradish at 4 ppm. There are no processed
commodities from horseradish. Secondary residues are not expected in
animal commodities as a result of this Section 18 use, as no livestock
feed items are associated with horseradish.
D. International Residue Limits
There are no Codex residue limits established for sethoxydim, and
no Canadian or Mexican residue limits for sethoxydim use on
horseradish. Harmonization is thus not an issue for this Section 18
action.
E. Rotational Crop Restrictions.
There are no rotational crop restrictions associated with this use,
and none are required As stated previously, sethoxydim is a non-
persistent, highly mobile compound in soil and water environments.
VI. Conclusion
Therefore, the tolerance is established for residues of sethoxydim
and its metabolites containing the 2-cyclohexen-1-one moiety in or on
horseradish at 4 ppm.
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 October 21, 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-300533] (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 Hwy., 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.
IX. Regulatory Assessment Requirements
This final rule establishes a time-limited tolerance under FFDCA
section 408(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
[[Page 44565]]
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 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 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).
List of Subjects in 40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: August 15, 1997.
Peter Caulkins,
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. In Sec. 180.412, by adding text to paragraph (b) to read as
follows:
Sec. 180.412 Sethoxydim: tolerance for residues.
* * * * *
(b) Section 18 emergency exemptions. A time-limited tolerance is
established for combined residues of the herbicide sethoxydim and its
metabolites containing the 2-cyclohexen-1-one moiety, calculated as the
herbicide in connection with use of the pesticide under section 18
emergency exemptions granted by EPA. This tolerance will expire and is
revoked on the date specified in the following table:
------------------------------------------------------------------------
Expiration/
Commodity Parts per million revocation date
------------------------------------------------------------------------
Horseradish..................... 4 September 30, 1998
------------------------------------------------------------------------
* * * * *
[FR Doc. 97-22377 Filed 8-21-97; 8:45 am]
BILLING CODE 6560-50-F
