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Sethoxydim; Pesticide Tolerance
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: February 28, 2007 (Volume 72, Number 39)]
[Rules and Regulations]
[Page 8916-8923]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr28fe07-9]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[EPA-HQ-OPP-2006-0321; FRL-8115-8]
Sethoxydim; Pesticide Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation establishes tolerances for combined residues
of sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-
hydroxy-2-cyclohexen-1-one {time} and its metabolites containing the 2-
cyclohexen-1-one moiety (calculated as sethoxydim) in or on buckwheat
grain, buckwheat flour, okra, borage seed, borage meal, fresh dillweed
leaves, radish tops, turnip greens, and vegetable, root and tuber,
group 1. Interregional Research Project No. 4 (IR-4) requested these
tolerances under the Federal Food, Drug, and Cosmetic Act (FFDCA), as
amended by the Food Quality Protection Act of 1996 (FQPA).
DATES: This regulation is effective February 28, 2007. Objections and
requests for hearings must be received on or before April 30, 2007, and
must be filed in accordance with the instructions provided in 40 CFR
part 178 (see also Unit I.C. of the SUPPLEMENTARY INFORMATION).
ADDRESSES: EPA has established a docket for this action under docket
identification (ID) number EPA-HQ-OPP-2006-0321. All documents in the
docket are listed in the index for the docket. Although listed in the
index, some information is not publicly available, e.g., Confidential
Business Information (CBI) or other information whose disclosure is
restricted by statute. Certain other material, such as copyrighted
material, is not placed on the Internet and will be publicly available
only in hard copy form. Publicly available docket materials are
available in the electronic docket at http://www.regulations.gov, or,
if only available in hard copy, at the OPP Regulatory Public Docket in
Rm. S-4400, One Potomac Yard (South Building), 2777 S. Crystal Drive,
Arlington, VA. The Docket Facility is open from 8:30 a.m. to 4 p.m.,
Monday through Friday,
[[Page 8917]]
excluding legal holidays. The Docket telephone number is (703) 305-5805.
FOR FURTHER INFORMATION CONTACT: Barbara Madden, Registration Division
(7505P), Office of Pesticide Programs, Environmental Protection Agency,
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone
number: (703) 305-6463; e-mail address: Madden.Barbara@epa.gov.
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this Action Apply to Me?
You may be potentially affected by this action if you are an
agricultural producer, food manufacturer, or pesticide manufacturer.
Potentially affected entities may include, but are not limited to:
? Crop production (NAICS 111), e.g., agricultural workers;
greenhouse, nursery, and floriculture workers; farmers.
? Animal production (NAICS 112), e.g., cattle ranchers and
farmers, dairy cattle farmers, livestock farmers.
? Food manufacturing (NAICS 311), e.g., agricultural
workers; farmers; greenhouse, nursery, and floriculture workers;
ranchers; pesticide applicators.
? Pesticide manufacturing (NAICS 32532), e.g., agricultural
workers; commercial applicators; farmers; greenhouse, nursery, and
floriculture workers; residential users.
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in this unit could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether this action might apply to certain entities. If you have any
questions regarding the applicability of this action to a particular
entity, consult the person listed under FOR FURTHER INFORMATION CONTACT.
B. How Can I Access Electronic Copies of this Document?
In addition to accessing an electronic copy of this Federal Register
document through the electronic docket at http://www.regulations.gov,
you may access this Federal Register document electronically through the
EPA Internet under the ``Federal Register'' listings at
http://www.epa.gov/fedrgstr. You may also access a frequently updated
electronic version of 40 CFR part 180 through the Government Printing
Office's pilot e-CFR site at http://www.gpoaccess.gov/ecfr. To access
the OPPTS Harmonized Guidelines referenced in this document, go directly
to the guidelines at http://www.epa.gov/opptsfrs/home/guidelin.htm.
C. Can I File an Objection or Hearing Request?
Under section 408(g) of the FFDCA, as amended by the FQPA, any
person may file an objection to any aspect of this regulation and may
also request a hearing on those objections. The EPA procedural
regulations which govern the submission of objections and requests for
hearings appear in 40 CFR part 178. You must file your objection or
request a hearing on this regulation in accordance with the
instructions provided in 40 CFR part 178. To ensure proper receipt by
EPA, you must identify docket ID number EPA-HQ-OPP-2006-0321 in the
subject line on the first page of your submission. All requests must be
in writing, and must be mailed or delivered to the Hearing Clerk on or
before April 30, 2007.
In addition to filing an objection or hearing request with the
Hearing Clerk as described in 40 CFR part 178, please submit a copy of
the filing that does not contain any CBI for inclusion in the public
docket that is described in ADDRESSES. Information not marked
confidential pursuant to 40 CFR part 2 may be disclosed publicly by EPA
without prior notice. Submit your copies, identified by docket ID
number EPA-HQ-OPP-2006-0321, by one of the following methods:
? Federal eRulemaking Portal: http://www.regulations.gov.
Follow the on-line instructions for submitting comments.
? Mail: Office of Pesticide Programs (OPP) Regulatory Public
Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania
Ave., NW., Washington, DC 20460-0001.
? Delivery: OPP Regulatory Public Docket (7502P),
Environmental Protection Agency, Rm. S-4400, One Potomac Yard (South
Building), 2777 S. Crystal Drive, Arlington, VA. Deliveries are only
accepted during the Docket's normal hours of operation (8:30 a.m. to 4
p.m., Monday through Friday, excluding legal holidays). Special
arrangements should be made for deliveries of boxed information. The
Docket telephone number is (703) 305-5805.
II. Background and Statutory Findings
In the Federal Register of July 5, 2006 (71 FR 38154) (FRL-8074-7),
EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21 U.S.C.
346a(d)(3), announcing the filing of pesticide petitions (PP 0E6204 and
4E6885) by IR-4, 500 College Road East, Suite 201 W, Princeton, NJ
08540. The petitions requested that 40 CFR 180.412 be amended by
establishing tolerances for combined residues of the herbicide
sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-
2-cyclohexen-1-one{time} and its metabolites containing the 2-
cyclohexen-1-one moiety in or on turnip tops at 5.0 parts per million
(ppm) (PP 0E6204) and buckwheat, grain at 20 ppm; buckwheat, flour at
20 ppm; borage; seed at 5.0 ppm; borage, meal at 40 ppm; borage, oil at
40 ppm; dill, fresh leaves at 10 ppm; dill, dried leaves at 10 ppm;
okra at 4.0 ppm; vegetable root, except sugar beet, group 1B at 4.0
ppm; and radish tops at 5.0 ppm (4E6885). That notice referenced a
summary of the petition prepared by BASF Corporation, the registrant,
that is available in EPA's electronic docket. There were no comments
received in response to the notice of filing.
Upon completing review of the current sethoxydim database, the
Agency concluded that the appropriate tolerance levels and preferred
commodity terms for sethoxydim residues in or on pending crops should
be established as follows: Buckwheat, grain at 19 ppm; buckwheat, flour
at 25 ppm; okra at 2.5 ppm; borage, seed at 6.0 ppm; borage, meal at 10
ppm; dillweed, fresh leaves at 10 ppm; radish, tops at 4.5 ppm; turnip,
greens at 5.0 ppm and Vegetable, root and tuber, group 1 at 4.0 ppm.
Vegetable, root and tuber, group 1 incorporates both the request for
vegetable root, except sugar beet, group 1B at 4.0 ppm and existing
tolerances for carrot, roots at 1.0 ppm; horseradish at 4.0 ppm; beet,
garden at 1.0 ppm; beet, sugar, root at 1.0 ppm; and tuberous and corm
vegetable subgroup 1D at 4.0 ppm. Turnip, greens replaces the term
turnip tops. In addition, the proposed tolerance for borage oil was
withdrawn because no separate tolerance is required since oil is
covered by the borage seed tolerance and the proposed tolerance for
dill, dried leaves was withdrawn because no separate tolerance is
required since dried dillweed is covered by the fresh dillweed tolerance.
EPA is also deleting several established tolerances in section
180.412(a) that are no longer needed as a result of this action. The
revisions to section 180.412(a) are as follows: Delete beet, garden at
1.0 ppm; beet, sugar, roots at 1.0 ppm; carrot, roots at 1.0 ppm;
horseradish at 4.0 ppm; and tuberous and corm vegetable crop subgroup
at 4.0 ppm. All of these tolerances are replaced with vegetable, root
and tuber, group 1 at 4.0 ppm.
Section 408(b)(2)(A)(i) of FFDCA allows EPA to establish a
tolerance (the
[[Page 8918]]
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)
of FFDCA 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) of
FFDCA requires EPA to give special consideration to exposure of infants
and children to the pesticide chemical residue in establishing a
tolerance and to ``ensure that there is a reasonable certainty that no
harm will result to infants and children from aggregate exposure to the
pesticide chemical residue. . . .''
EPA performs a number of analyses to determine the risks from
aggregate exposure to pesticide residues. For further discussion of the
regulatory requirements of section 408 of the FFDCA and a complete
description of the risk assessment process, see
http://www.epa.gov/fedrgstr/EPA-PEST/1997/November/Day-26/p30948.htm and
http://www.epa.gov/fedrgstr/EPA-PEST/2003/July/Day-30/p19357.htm
III. Aggregate Risk Assessment and Determination of Safety
Consistent with section 408(b)(2)(D) of FFDCA, 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 and to
make a determination on aggregate exposure, consistent with section
408(b)(2) of FFDCA, for tolerances for combined residues of sethoxydim
and its metabolites containing the 2-cyclohexen-1-one moiety on
buckwheat, grain at 19 ppm; buckwheat, flour at 25 ppm; okra at 2.5
ppm; borage, seed at 6.0 ppm; borage, meal at 10 ppm; dillweed, fresh
leaves at 10 ppm; radish, tops at 4.5 ppm; turnip, greens at 5.0 ppm
and vegetable, root and tuber, group 1 at 4.0 ppm. EPA's assessment of
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. Specific information on the studies received and the nature
of the toxic effects caused by sethoxydim as well as the no-observed-
adverse-effect-level (the NOAEL) and the lowest-observed-adverse-
effect-level (the LOAEL) from the toxicity studies can be found in the
final rule published in the Federal Register of September 29, 2003 (68
FR 55858) (http://www.epa.gov/EPA-PEST/2003/September/Day-29/p24562.htm).
B. Toxicological Endpoints
For hazards that have a threshold below which there is no
appreciable risk, the dose at which the (NOAEL) from the toxicology
study identified as appropriate for use in risk assessment is used to
estimate the toxicological level of concern (LOC). However, the (LOAEL)
of concern are identified is sometimes used for risk assessment if no
NOAEL was achieved in the toxicology study selected. An uncertainty
factor (UF) is applied to reflect uncertainties inherent in the
extrapolation from laboratory animal data to humans and in the
variations in sensitivity among members of the human population as well
as other unknowns.
The linear default risk methodology (Q*) is the primary method
currently used by the Agency to quantify non-threshold hazards such as
cancer. The Q* approach assumes that any amount of exposure will lead
to some degree of cancer risk, estimates risk in terms of the
probability of occurrence of additional cancer cases. More information
can be found on the general principles EPA uses in risk
characterization at be found on the general principles EPA uses in risk
characterization at http://www.epa.gov/pesticides/health/human.htm.
A summary of the toxicological endpoints for sethoxydim used for
human risk assessment can be found at http://www.regulations.gov in document
0003 (page 9) in Docket ID EPA-HQ-OPP-2006-0321. To locate this
information on the Regulations.gov website follow these steps:
Select ``Advanced Search'', then ``Docket Search.''
In the ``Keyword'' field type the chemical name or insert the
applicable ``Docket ID number.'' (example: EPA-HQ-OPP-2005-9999).
Click the ``Submit''button.
Follow the instructions on the regulations.gov web site to view the
index for the docket and access available documents.
C. Exposure Assessment
1. Dietary exposure from food and feed uses. Tolerances have been
established (40 CFR 180.412) for the combined residues of sethoxydim
and its 2-cyclohexen-1-one moiety containing metabolites, in or on a
variety of raw agricultural commodities. Tolerances have also been
established for combined residues of sethoxydim in or on milk, egg, and
fat, meat, and meat byproducts of cattle, goat, hog, horse, poultry and
sheep. Risk assessments were conducted by EPA to assess dietary
exposures from sethoxydim in food as follows:
i. Acute exposure. Quantitative acute dietary exposure and 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.
In conducting the acute dietary exposure assessment EPA used the
Dietary Exposure Evaluation Model software with the Food Commodity
Intake Database (DEEM-FCID\TM\), which incorporates food consumption
data as reported by respondents in the USDA 1994-1996 and 1998
Nationwide Continuing Surveys of Food Intake by Individuals (CSFII),
and accumulated exposure to the chemical for each commodity. The
following assumptions were made for the acute exposure assessments: For
all proposed new uses and for all commodities in Vegetable, root and
tuber, group 1, tolerance level residues and 100 percent crop treated
(PCT) were assumed. For the remaining crops with existing tolerances
available maximum PCT values were used. Tolerance level residues were
assumed for most crops except for grapes, oranges, potatoes, tomatoes,
strawberries, apples, pears and other pome fruits where anticipated
residues were calculated through the incorporation of field trial data.
Empirical processing data for apples, grapes, tomatoes, potatoes and
oranges were used, and were sometimes translated to other members of
the crop group. For livestock commodities, the available PCT
information was incorporated into the dietary burden calculation and
the feeding studies were used to determine the appropriate residue
level, however at least one food item in each diet was assumed to be
100 PCT. PCT information was incorporated into the acute exposure and
risk assessments through use of probabilistic risk assessment model.
ii. Chronic exposure. In conducting the chronic dietary exposure
assessment EPA used the DEEM\TM\ software with the Food Commodity
Intake Database, which incorporates food consumption data as reported
by respondents in the United States Department of Agriculture
[[Page 8919]]
(USDA) 1994-1996 and 1998 Nationwide Continuing Surveys of Food Intake
by Individuals (CSFII), and accumulated exposure to the chemical for
each commodity. The following assumptions were made for the chronic
exposure assessments: For the proposed new uses and all commodities in
Vegetable, root and tuber, group 1 tolerance level residues and 100% CT
were assumed. For most of the crops with existing tolerances, tolerance
level residues and average PCT values were assumed. PCT data for some
livestock feeds were incorporated into the calculations of the
theoretical dietary burdens for livestock, which were then used in
conjunction with the available feeding studies to determine the
anticipated residues in livestock commodities.
iii. Cancer. The Agency has classified sethoxydim as not likely to
be a human carcinogen based on lack of evidence of carcinogenicity in
rats and mice. Therefore, a cancer dietary exposure assessment was not
performed
iv. Anticipated residue and PCT information. Section 408(b)(2)(E)
of the FFDCA authorizes EPA to use available data and information on
the anticipated residue levels of pesticide residues in food and the
actual levels of pesticide chemicals that have been measured in food.
If EPA relies on such information, EPA must pursuant to section
408(f)(1) require that data be provided 5 years after the tolerance is
established, modified, or left in effect, demonstrating that the levels
in food are not above the levels anticipated. Following the initial
data submission, EPA is authorized to require similar data on a time
frame it deems appropriate. For the present action, EPA will issue such
Data Call-Ins for information relating to anticipated residues as are
required by FFDCA section 408(b)(2)(E) and authorized under FFDCA
section 408(f)(1). Such Data Call-Ins will be required to be submitted
no later than 5 years from the date of issuance of this tolerance.
Section 408(b)(2)(F) of FFDCA states that the Agency may use data
on the actual percent of food treated for assessing chronic dietary
risk only if the Agency can make the following findings: Condition 1,
that the data used are reliable and provide a valid basis to show what
percentage of the food derived from such crop is likely to contain such
pesticide residue; Condition 2, that the exposure estimate does not
underestimate exposure for any significant subpopulation group; and
Condition 3, if data are available on pesticide use and food
consumption in a particular area, the exposure estimate does not
understate exposure for the population in such area. In addition, the
Agency must provide for periodic evaluation of any estimates used. To
provide for the periodic evaluation of the estimate of PCT as required
by section 408(b)(2)(F) of FFDCA, EPA may require registrants to submit
data on PCT.
The Agency used PCT information for the chronic dietary risk
assessment as follows: 1% apples, 1% apricots, 6% globe artichokes, 5%
asparagus, 14% dry beans, 9% lima beans, 8% snap beans, 5% garden beet
tops, 1% broccoli, 5% cabbage, 8% cantaloupes, 2% cauliflower, 1%
cherries, 2% collards, 1% corn, 1% cotton, 8% cranberries, 6%
cucumbers, 5% eggplants, 38% flax, 1% grapes, 1% grapefruits, 5%
lemons, 1% lettuce, 1% nectarines, 3% oranges, 2% succulent peas, 14%
dry peas, 1% peaches, 5% peanuts, 1% pears, 3% bell peppers, 6% nonbell
peppers, 4% potatoes, 8% pumpkins, 4% rapeseed, 6% rhubarb, 2%
soybeans, 1% spinach, 8% summer squash, 5% strawberry, 14% sunflower,
4% tomatoes, 5% turnip greens, and 12% watermelons.
EPA uses an average PCT for chronic dietary risk analysis. The
average PCT figure for each existing use is derived by combining
available Federal, State, and private market survey data for that use,
averaging by year, averaging across all years, and rounding up to the
nearest multiple of five percent except for those situations in which
the average PCT is less than one. In those cases < 1% is used as the
average and < 2.5% is used as the maximum. EPA uses a maximum PCT for
acute dietary risk analysis. The maximum PCT figure is the single
maximum value reported overall from available federal, state, and
private market survey data on the existing use, across all years, and
rounded up to the nearest multiple of five percent. In most cases, EPA
uses available data from United States Department of Agriculture/
National Agricultural Statistics Service (USDA/NASS), Proprietary
Market Surveys, and the National Center for Food and Agriculture Policy
(NCFAP) for the most recent six years.
The Agency believes that the three conditions listed III.C.1.iv.
have been met. With respect to Condition 1, PCT estimates are derived
from Federal and private market survey data, which are reliable and
have a valid basis. The Agency is reasonably certain that the
percentage of the food treated is not likely to be an underestimation.
As to Conditions 2 and 3, regional consumption information and
consumption information for significant subpopulations is taken into
account through EPA's computer-based model for evaluating the exposure
of significant subpopulations including several regional groups. Use of
this consumption information in EPA's risk assessment process ensures
that EPA's exposure estimate does not understate exposure for any
significant subpopulation group and allows the Agency to be reasonably
certain that no regional population is exposed to residue levels higher
than those estimated by the Agency. Other than the data available
through national food consumption surveys, EPA does not have available
information on the regional consumption of food to which sethoxydim may
be applied in a particular area.
2. Dietary exposure from drinking water. The Agency lacks
sufficient monitoring exposure data to complete a comprehensive dietary
exposure analysis and risk assessment for sethoxydim in drinking water.
Because the Agency does not have comprehensive monitoring data,
drinking water concentration estimates are made by reliance on
simulation or modeling taking into account data on the physical
characteristics of sethoxydim. Further information regarding EPA
drinking water models used in pesticide exposure assessment can be
found at http://www.epa.gov/oppefed1/models/water/index.htm.
Based on the First Index Screening Tool Reservoir (FIRST) and
Screening Concentration in Groundwater (SCI-GROW) models, the estimated
environmental concentrations (EECs) of sethoxydim for acute exposures
are estimated to be 130 parts per billion (ppb) for surface water and
1.5 ppb for ground water. The EECs for chronic exposures are estimated
to be 16 ppb for surface water and 1.5 ppb for ground water.
Modeled estimates of drinking water concentrations were directly
entered into the dietary exposure model. For acute dietary risk
assessment, the water concentration value of 130 ppb was used to assess
the contribution to drinking water. For chronic dietary risk
assessment, the water concentration value of 16 ppb was used to assess
the contribution to drinking water.
3. From non-dietary exposure. The term ``residential exposure'' is
used in this document to refer to non-occupational, non-dietary
exposure (e.g., for lawn and garden pest control, indoor pest control,
termiticides, and flea and tick control on pets).
Sethoxydim is currently registered for use on the following
residential non-dietary sites: Ornamentals and flowering
[[Page 8920]]
plants, recreational areas, rights-of-way, along fences and hedgerows,
and public and commercial buildings/structures (non-agricultural-
outdoors). The risk assessment was conducted using the following
residential exposure assumptions: Homeowners who apply sethoxydim to
ornamental gardens and turf may be exposed for short-term (up to 30
days) durations via the dermal and inhalation routes. Short-term post
application exposures to children may result from incidental oral
contact via hand-to-mouth, turf-to-mouth, and soil-to-mouth activities
with treated turf. No dermal toxicity endpoints were identified,
therefore, only exposure from inhalation (adult handlers) and
incidental ingestion (children) were assessed. For short-term and
intermediate-term aggregate exposure, the inhalation exposures
estimated for adult handlers cannot be combined with dietary exposure
due to lack of common toxicity via the oral [transitory clinical signs:
Irregular gait at doses of 650 milligrams/kilogram (mg/kg) and 1,000
mg/kg and inhalation (hepatotoxicity)] routes of exposure. Therefore,
only short-term aggregate exposures from incidental ingestion for
children via hand-to-mouth, turf-to-mouth, and soil-to-mouth activities
with treated turf were assessed.
4. Cumulative effects from substances with a common mechanism of
toxicity. Section 408(b)(2)(D)(v) of the FFDCA 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.''
Unlike other pesticides for which EPA has followed a cumulative
risk approach based on a common mechanism of toxicity, EPA has not made
a common mechanism of toxicity finding as to sethoxydim and any other
substances and sethoxydim does not appear to produce a toxic metabolite
produced by other substances. For the purposes of this tolerance
action, therefore, EPA has not assumed that sethoxydim has a common
mechanism of toxicity with other substances. For information regarding
EPA's efforts to determine which chemicals have a common mechanism of
toxicity and to evaluate the cumulative effects of such chemicals, see
the policy statements released by EPA's Office of Pesticide Programs
concerning common mechanism determinations and procedures for
cumulating effects from substances found to have a common mechanism on
EPA's website at http://www.epa.gov/pesticides/cumulative.
D. Safety Factor for Infants and Children
1. In general. Section 408 of FFDCA provides that EPA shall apply
an additional tenfold margin of safety for infants and children in the
case of threshold effects to account for prenatal and postnatal
toxicity and the completeness of the data base on toxicity and exposure
unless EPA determines based on reliable data 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. In
applying this provision, EPA either retains the default value of 10X
when reliable data do not support the choice of a different factor, or,
if reliable data are available, EPA uses a different additional safety
factor value based on the use of traditional uncertainty factors and/or
special FQPA safety factors, as appropriate.
2. Prenatal and postnatal sensitivity. Since there is evidence of
increased susceptibility of the young following exposure to sethoxydim
in the rat developmental study and the rat reproduction study, the EPA
performed a Degree of Concern Analysis to: 1. Determine the level of
concern for the effects observed when considered in the context of all
available toxicity data; and 2. Identify any residual uncertainties
after establishing toxicity endpoints and traditional uncertainty
factors to be used in the risk assessment of this chemical. If residual
uncertainties are identified, EPA examines whether these residual
uncertainties can be addressed by a special FQPA safety factor and, if
so, the size of the factor needed. The results of Degree of Concern
analysis for sethoxydim are presented as follows:
The degree of concern is low for the fetal effects in the
developmental rat study since the fetal anomalies were seen only at the
high dose (650 mg/kg/day) which is close to the Limit Dose (1,000 mg/
kg/day), they were seen in the presence of maternal toxicity (irregular
gait) and clear NOAELs/LOAELs were established for maternal and
developmental toxicities.
EPA has determined that the degree of concern was low for prenatal
and/or postnatal toxicity resulting from exposure to sethoxydim toxicity.
3. Conclusion. In the final rule published in the Federal Register
of September 29, 2003 (68 FR 55858) (FRL-7328-6) (http://www.epa.gov/
EPA-PEST/2003/September/Day-29/p24562.htm). EPA retained the additional
10X FQPA safety factor in the form of a Data base Uncertainty Factor
because EPA had required submission of subchronic and developmental
neurotoxicity studies due to various clinical signs in the rat
developmental study and evidence of developmental abnormalities in the
rat developmental and reproductive studies. In December of 2004, the
EPA revisited the requirement for the subchronic and developmental
neurotoxicity studies and determined that the evidence does not support
the need for neurotoxicity studies for the reasons discussed below.
First, EPA concluded that the clinical signs seen in the rat
developmental study were not neurotoxicity. The clinical signs
following sethoxydim exposure in that study were irregular gait,
decreased activity, excessive salivation, and anogenital staining.
These effects were only observed in animals receiving very high doses
of sethoxydim (650 mg/kg/day and 1,000 mg/kg/day). Irregular gait was
observed in 12/24 dams at 650 mg/kg/day and 10/10 dams at 1,000 mg/kg/
day on the first day of dosing, after 3 doses the signs began to
dissipate. Decreased activity was noted in 1/34 dams at 650 mg/kg/day
and in 4/10 dams at 1,000 mg/kg/day and reversed after several days.
Excessive salivation was noted in 23/34 dams at 650 mg/kg/day and 10/10
dams at 1,000 mg/kg/day. Anogenital staining was documented in 13/34
dams at 650 mg/kg/day and 7/10 dams at 1,000 mg/kg/day. All clinical
signs reported were transient, with the exception of the anogenital
staining which did not reverse. Because the clinical signs occurred
shortly after dosing, only occurred at very high treatment doses (over
one half the limit dose) and were transitory, it is unlikely that the
signs observed are the result of a primary systemic effect on the
nervous system but, rather, are reflective of the general toxicity at
the high dose. It should be noted that clinical signs indicative of
nervous system effects were not observed in any other standard toxicity
study for sethoxydim. Although none of these other studies dosed up to
650 and 1,000 mg/kg/day, a maximum tested dose was reached because of
evidence of other toxicities (e.g., liver effects or body weight
reductions).
Second, EPA found that there were no developmental effects seen in
the rat and rabbit prenatal studies indicative of an effect on the
nervous system. The main effect seen in the rat and rabbit prenatal
studies was an increased incidence of fetal skeletal variations due
[[Page 8921]]
to delayed ossification. In the rat prenatal study, tail abnormalities
(filamentous tail or lack of a tail) were noted. These abnormalities
were observed at a very low incidence (10 fetuses in 7 litters, 650
milligrams/kilogram/body weight/day (mg/kg/bwt/day and at high
treatment doses (650 and 1,000 mg/kg/day). In the 2-generation
reproduction study in rat, a tail anomaly (short, thread-like tail, no
anal opening, hindlimbs curved toward central midline) was found in one
pup in the F2b generation (1/344 total pups; in 1/4 litters). Tail
abnormalities are sometimes thought to relate to central nervous system
(CNS) malformations; however, in this case, these tail abnormalities
are not likely to be the result of a primary neurotube effect. In the
rat prenatal study, there is no description of any effect on neural
tube derived structures. Furthermore, the class of compounds,
cyclohexones (which sethoxydim is a member), do not demonstrate
neurotoxicity or developmental malformations of the nervous system.
Therefore, after a weight-of-evidence examination of all the
toxicological studies available in the data base, the previous
requirement for a neurotoxicity studies have been waived.
In light of its finding that neurotoxicity studies are not needed,
EPA has now determined that reliable data show that it would be safe
for infants and children to reduce the FQPA safety factor to 1X. That
decision is based on the following findings:
1. The toxicity database for sethoxydim is complete.
2. There is no indication that sethoxydim is a neurotoxic chemical
and there is no need for a developmental neurotoxicity study or
additional uncertainty factors to account for neurotoxicity.
3. Although there is qualitative evidence of increased
susceptibility in the prenatal developmental studies in rats and
rabbits, the risk assessment team did not identify any residual
uncertainties after establishing toxicity endpoints and traditional
uncertainty factors to be used in the risk assessment for sethoxydim.
The degree of concern for pre-and/or postnatal toxicity is low.
4. There are no residual uncertainties identified in the exposure
databases. The dietary food exposure assessments were performed based
on tolerance level residues and 100 PCT for all proposed new uses and
for all commodities in Vegetable, root and tuber, group 1. For most of
the remaining crops available maximum PCT treated values were used for
acute dietary assessment and average PCT values were assumed for
chronic dietary assessment. Tolerance level residues were assumed for
crops with existing tolerances or anticipated residues were calculated
through the incorporation of field trial data. Conservative ground and
surface water modeling estimates were used. Similarly conservative
Residential SOPs were used to assess post-application exposure to children
as well as incidental oral exposure of toddlers. These assessments
will not underestimate the exposure and risks posed by sethoxydim.
E. Aggregate Risks and Determination of Safety
Safety is assessed for acute and chronic risks by comparing
aggregate exposure to the pesticide to the acute population adjusted
dose (``aPAD'') and chronic population adjusted dose (``cPAD''). The
aPAD and cPAD are calculated by dividing the LOC by all applicable
uncertainty/safety factors. For linear cancer risks, EPA calculates the
probability of additional cancer cases given aggregate exposure. Short-
term, intermediate, and long-term risks are evaluated by comparing
aggregate exposure to the LOC to ensure that the margin of exposure
(``MOE'') called for by the product of all applicable uncertainty/
safety factors is not exceeded.
1. Acute risk. Using the exposure assumptions discussed in this
unit for acute exposure, the acute dietary exposure from food and water
to sethoxydim will occupy 11% of the aPAD for the U.S. population, 7.2%
of the aPAD for females 13 years and older, 14% of the aPAD for all
infants (< 1 year old), and 20% of the aPAD for children 1-2 years old,
the subpopulation at greatest exposure
2. Chronic risk. Using the exposure assumptions described in this
unit for chronic exposure, EPA has concluded that exposure to
sethoxydim from food and water will utilize 6.9% of the cPAD for the
U.S. population, 15% of the cPAD for all infants (< 1 year old), and 16%
of the cPAD for children 1-2 years old, the subpopulation at greatest
exposure. Based on the use pattern, chronic residential exposure to
residues of sethoxydim is not expected.
3. Short-term risk. Short-term aggregate exposure takes into
account residential exposure plus chronic exposure to food and water
(considered to be a background exposure level). Sethoxydim is currently
registered for use that could result in short-term residential exposure
and the Agency has determined that it is appropriate to aggregate
chronic food and water and short-term exposures for sethoxydim.
Using the exposure assumptions described in this unit for short-
term exposures, EPA has concluded that food, water and residential
exposures aggregated result in aggregate MOEs of 5,700 for children/
toddlers 1-2 years of age. Since this is the subpopulation with the
highest estimated food and water exposures and the calculated MOE of
5,700 is substantially greater than the target MOE of 100 EPA has no
concern for short-term aggregate risk for other subpopulations as well.
4. Intermediate-term risk. Intermediate-term aggregate exposure
takes into account residential exposure plus chronic exposure to food
and water (considered to be a background exposure level).
Though residential exposure could occur with the use of sethoxydim
intermediate-term exposures are not expected. Only risks associated
with short-term exposures of up to 30 days were assessed.
5. Aggregate cancer risk for U.S. population. The Agency has
classified sethoxydim as not likely to be a human carcinogen based on
lack of evidence of carcinogenicity in rats and mice. Sethoxydim is not
expected to pose a cancer risk.
6. Determination of safety. Based on these risk assessments, EPA
concludes that there is a reasonable certainty that no harm will result
to the general population, and to infants and children from aggregate
exposure to sethoxydim residues.
IV. Other Considerations
A. Analytical Enforcement Methodology
Adequate enforcement methodology (gas-liquid chromatography with
flame photometric detection in the sulfur mode) is available BASF
Wyandotte Corporations' (BWCs) Method No. 30, 3/15/82; MRID 44864501;
Method I, PAM II to enforce the tolerance expression for the purpose of
this request.
B. International Residue Limits
There are currently no Codex maximum residue levels for sethoxydim.
V. Conclusion
Therefore, the tolerance is established for combined residues of
sethoxydim {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-
2-cyclohexen-1-one{time} and its metabolites containing the 2-
cyclohexen-1-one moiety (calculated as sethoxydim), in or on buckwheat,
grain at 19 ppm; buckwheat, flour at 25 ppm; okra at 2.5 ppm; borage,
seed at 6.0 ppm; borage, meal at 10 ppm; dillweed, fresh leaves
[[Page 8922]]
at 10 ppm; radish, tops at 4.5 ppm; turnip, greens at 5.0 ppm and
vegetable, root and tuber, group 1 at 4.0 ppm.
VI. Statutory and Executive Order Reviews
This final rule establishes a tolerance under section 408(d) of
FFDCA in response to a petition submitted to the Agency. The Office of
Management and Budget (OMB) has exempted these types of actions from
review under Executive Order 12866, entitled Regulatory Planning and
Review (58 FR 51735, October 4, 1993). Because this rule has been
exempted from review under Executive Order 12866 due to its lack of
significance, this rule is not subject to Executive Order 13211,
Actions Concerning Regulations That Significantly Affect Energy Supply,
Distribution, or Use (66 FR 28355, May 22, 2001). 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) (Public Law
104-4). Nor does it require any special considerations under Executive
Order 12898, entitled Federal Actions to Address Environmental Justice
in Minority Populations and Low-Income Populations (59 FR 7629,
February 16, 1994); or OMB review or any Agency action under Executive
Order 13045, entitled Protection of Children from Environmental Health
Risks and Safety Risks (62 FR 19885, April 23, 1997). This action does
not involve any technical standards that would require Agency
consideration of voluntary consensus standards pursuant to section
12(d) of the National Technology Transfer and Advancement Act of 1995
(NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272 note). Since
tolerances and exemptions that are established on the basis of a
petition under section 408(d) of FFDCA, 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. In addition, the Agency has determined that this
action will not have a substantial direct effect on States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government, as specified in Executive Order 13132, entitled Federalism
(64 FR 43255, August 10, 1999). Executive Order 13132 requires EPA to
develop an accountable process to ensure ``meaningful and timely input
by State and local officials in the development of regulatory policies
that have federalism implications.'' ``Policies that have federalism
implications'' is defined in the Executive Order to include regulations
that have ``substantial direct effects on the States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government.'' This final rule directly regulates growers, food
processors, food handlers and food retailers, not States. This action
does not alter the relationships or distribution of power and
responsibilities established by Congress in the preemption provisions
of section 408(n)(4) of FFDCA. For these same reasons, the Agency has
determined that this rule does not have any ``tribal implications'' as
described in Executive Order 13175, entitled Consultation and
Coordination with Indian Tribal Governments (59 FR 22951, November 6,
2000). Executive Order 13175, requires EPA to develop an accountable
process to ensure ``meaningful and timely input by tribal officials in
the development of regulatory policies that have tribal implications.''
``Policies that have tribal implications'' is defined in the Executive
Order to include regulations that have ``substantial direct effects on
one or more Indian tribes, on the relationship between the Federal
Government and the Indian tribes, or on the distribution of power and
responsibilities between the Federal Government and Indian tribes.''
This rule will not have substantial direct effects on tribal
governments, on the relationship between the Federal Government and
Indian tribes, or on the distribution of power and responsibilities
between the Federal Government and Indian tribes, as specified in
Executive Order 13175. Thus, Executive Order 13175 does not apply to
this rule.
VII. Congressional Review Act
The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. EPA will submit 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 United States prior
to publication of this final rule in the Federal Register. This final
rule 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: February 13, 2007.
Lois Rossi,
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. 321(q), 346a and 371.
? 2. Section 180.412 is amended in paragraph (a), in the table, by
removing the commodities ``Beet, garden'', ``Beet, sugar, roots'',
``Carrot, roots'' ``Horseradish'', and ``Tuberous and corm vegetable
crop subgroup''; and alphabetically adding commodities to read as follows:
Sec. 180.412 Sethoxydim: Tolerances for residues.
(a) * * *
------------------------------------------------------------------------
Commodity Parts per million
------------------------------------------------------------------------
* * * * *
Borage, meal........................ 10
Borage, seed........................ 6.0
Buckwheat, flour.................... 25
Buckwheat, grain.................... 19
* * * * *
Dillweed, fresh leaves.............. 10
* * * * *
Okra................................ 2.5
[[Page 8923]]
* * * * *
Radish, tops........................ 4.5
* * * * *
Turnip, greens...................... 5.0
* * * * *
Vegetable, root and tuber, group 1.. 4.0
------------------------------------------------------------------------
[FR Doc. E7-3010 Filed 2-27-07; 8:45 am]
BILLING CODE 6560-50-S