Document ID: EPA-HQ-OPP-2008-0811-0003
Agency: epa
Document Type: Rule
Title: Pesticide Tolerances: Mesotrione
Posted Date: 2009-12-18T05:00Z

[Federal Register: December 18, 2009 (Volume 74, Number 242)]
[Rules and Regulations]               
[Page 67119-67124]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr18de09-14]                         

[[Page 67119]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2008-0811; FRL-8799-1]

 
Mesotrione; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes a tolerance for residues of 
mesotrione in or on soybean, seed. Syngenta Crop Protection requested 
this tolerance under the Federal Food, Drug, and Cosmetic Act (FFDCA).

DATES: This regulation is effective December 18, 2009. Objections and 
requests for hearings must be received on or before February 16, 2010, 
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-2008-0811. All documents in the 
docket are listed in the docket index available at http://
www.regulations.gov. 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 Bldg.), 2777 S. Crystal Dr., Arlington, VA. The Docket 
Facility is open from 8:30 a.m. to 4 p.m., Monday through Friday, 
excluding legal holidays. The Docket Facility telephone number is (703) 
305-5805.

FOR FURTHER INFORMATION CONTACT: Joanne Miller, Registration Division 
(7505P), Office of Pesticide Programs, Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 305-6224; e-mail address: miller.joanne@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 those 
engaged in the following activities:
     Crop production (NAICS code 111).
     Animal production (NAICS code 112).
     Food manufacturing (NAICS code 311).
     Pesticide manufacturing (NAICS code 32532).
    This listing is not intended to be exhaustive, but rather to 
provide 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 electronically available documents 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 EPA's tolerance regulations 
at 40 CFR part 180 through the Government Printing Office's e-CFR cite 
at http://www.gpoaccess.gov/ecfr. To access the OPPTS Harmonized Test 
Guidelines referenced in this document, go directly to the guidelines 
at http://www.epa.gov/oppts/ and select ``Test Methods & Guidelines'' 
in the left side margin menu.

C. Can I File an Objection or Hearing Request?

    Under section 408(g) of FFDCA, 21 U.S.C. 346a, any person may file 
an objection to any aspect of this regulation and may also request a 
hearing on those objections. 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-2008-0811 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 as required by 40 CFR part 178 
on or before February 16, 2010.
    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 this copy, identified by docket ID number 
EPA-HQ-OPP-2008-0811, 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 
Bldg.), 2777 S. Crystal Dr., Arlington, VA. Deliveries are only 
accepted during the Docket Facility'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 Facility telephone number is (703) 305-5805.

II. Petition for Tolerance

    In the Federal Register of December 3, 2008 (73 FR 73648) (FRL-
8391-3), EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21 
U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP 
8F7456) by Syngenta Crop Protection, Inc., P.O. Box 18300, Greensboro, 
NC 27419. The petition requested that 40 CFR 180.571 be amended by 
establishing tolerances for residues of the herbicide, mesotrione, in 
or on soybeans at 0.01 parts per million (ppm). That notice referenced 
a summary of the petition prepared by Syngenta Crop Protection, the 
registrant, which is available to the public in the docket, http://
www.regulations.gov. There were no comments received in response to the 
notice of filing.
    To harmonize with the Food and Feed Commodity Vocabulary, http://
www.epa.gov/opphed01/foodfeed/index.htm/, EPA has amended the commodity 
listing to read: Soybean, seed at 0.01 ppm.

III. Aggregate Risk Assessment and Determination of Safety

    Section 408(b)(2)(A)(i) of 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) of FFDCA

[[Page 67120]]

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.''
    Consistent with section 408(b)(2)(D) of FFDCA, and the factors 
specified in 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 for the petitioned-for 
tolerances for residues of mesotrione, including its metabolites and 
degradates, in or on soybean, seed at 0.01 ppm. Compliance with the 
tolerance level is to be determined by measuring only mesotrione, 2-[4-
(methylsulfonyl)-2-nitrobenzoyl]-1,3-cyclohexanedione, in the raw 
agricultural commodity. EPA's assessment of exposures and risks 
associated with establishing tolerances follows.

A. Toxicological Profile

    EPA has evaluated the available toxicity data and considered its 
validity, completeness, and reliability as well as the relationship of 
the results of the studies to human risk. EPA has also considered 
available information concerning the variability of the sensitivities 
of major identifiable subgroups of consumers, including infants and 
children.
    Mesotrione has a low acute toxicity via the oral, dermal, and 
inhalation routes. It is a mild eye irritant, but is not a dermal 
irritant or a dermal sensitizer. In subchronic and chronic oral 
studies, ocular lesions, liver and kidney effects, and/or body weight 
decrements were the major adverse effects seen in the rat, mouse, and 
dog. Plasma tyrosine levels were increased in the rat, mouse and dog in 
the chronic and reproduction studies in which levels were measured. The 
ocular, liver and kidney effects are believed to be mediated by the 
high tyrosine levels in the blood caused by inhibition of the enzyme 
HPPD. Even though the rat is the most sensitive species to this effect 
compared to the dog and the mouse, EPA concluded that the mouse is a 
more appropriate model for assessing human risk than is the rat.
    There was no evidence of carcinogenic potential in either the rat 
chronic toxicity/carcinogenicity or mouse carcinogenicity studies and 
no concern for mutagenicity. No evidence of neurotoxicity or 
neuropathology was seen in the acute and subchronic neurotoxicity 
studies. In the multi-generation mouse reproduction study, one first 
generation male and one first generation female had retinal detachment 
with marked cataractous changes at the highest dose tested (>1,000 mg/
kg/day). In the subchronic toxicity dog study, the high-dose females 
had decreased absolute and relative brain weights; however, no 
microscopic abnormalities were noted in any brain tissues from the 
high-dose group and effect was not observed in the chronic toxicity dog 
study. There is some concern about the effects of elevated plasma 
tyrosine levels on the developing nervous system in children due to a 
report that some patients with tyrosinemia III (an autosomal recessive 
disorder in which HPPD is deficient) were presented with mental 
retardation or neurological symptoms. There was evidence of increased 
susceptibility of rats, mice and rabbits to in utero and/or post-natal 
exposure to mesotrione.
    Specific information on the studies received and the nature of the 
adverse effects caused by mesotrione as well as the no-observed-
adverse-effect-level (NOAEL) and the lowest-observed-adverse-effect-
level (LOAEL) from the toxicity studies can be found at http://
www.regulations.gov in the document ``Mesotrione: Human Health Risk 
Assessment for Section 3 New Uses on Soybeans'' in docket ID number 
EPA-HQ-OPP-2008-0811. Additionally, mesotrione toxicological data are 
discussed in the final rule published in the Federal Register of June 
21, 2001 (66 FR 33187) (FRL-6787-7).

B. Toxicological Endpoints

    For hazards that have a threshold below which there is no 
appreciable risk, a toxicological point of departure (POD) is 
identified as the basis for derivation of reference values for risk 
assessment. The POD may be defined as the highest dose at which no 
adverse effects are observed (the NOAEL) in the toxicology study 
identified as appropriate for use in risk assessment. However, if a 
NOAEL cannot be determined, the lowest dose at which adverse effects of 
concern are identified (the LOAEL) or a Benchmark Dose (BMD) approach 
is sometimes used for risk assessment. Uncertainty/safety factors (UFs) 
are used in conjunction with the POD to take into account 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. Safety is assessed for acute and chronic 
dietary risks by comparing aggregate food and water 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 POD by all applicable UFs. Aggregate short-, intermediate-
, and chronic-term risks are evaluated by comparing food, water, and 
residential exposure to the POD to ensure that the margin of exposure 
(MOE) called for by the product of all applicable UFs is not exceeded. 
This latter value is referred to as the Level of Concern (LOC).
    For non-threshold risks, the Agency assumes that any amount of 
exposure will lead to some degree of risk. Thus, the Agency estimates 
risk in terms of the probability of an occurrence of the adverse effect 
greater than that expected in a lifetime. For more information on the 
general principles EPA uses in risk characterization and a complete 
description of the risk assessment process, see http://www.epa.gov/
pesticides/factsheets/riskassess.htm.
    A summary of the toxicological endpoints for mesotrione used for 
human risk assessment is discussed in ``Mesotrione: Human Health Risk 
Assessment for Section 3 New Uses on Soybeans'' in docket ID number 
EPA-HQ-OPP-2008-0811. Additionally, mesotrione toxicological data are 
discussed in the final rule published in the Federal Register of June 
21, 2001 (66 FR 33187) (FRL-6787-7)

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. In evaluating dietary 
exposure to mesotrione, EPA considered exposure under the petitioned-
for tolerances as well as all existing mesotrione tolerances in 40 CFR 
180.571. EPA assessed dietary exposures from mesotrione 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 1-day or single exposure.
    No such effects were identified in the toxicological studies for 
mesotrione; therefore, a quantitative acute dietary exposure assessment 
is unnecessary.

[[Page 67121]]

    ii. Chronic exposure. In conducting the chronic dietary exposure 
assessment EPA used the food consumption data from the USDA 1994-1996 
and 1998 nationwide Continuing Surveys of Food Intake by Individuals 
(CSFII). As to residue levels in food, EPA assumed that all foods were 
treated for which there are proposed and established tolerances and 
that all the foods contain tolerance-level residues.
    iii. Cancer. Mesotrione was negative for carcinogenicity in feeding 
studies in rats and mice and was classified as ``not likely'' to be a 
human carcinogen. Therefore, a quantitative exposure assessment to 
evaluate cancer risk is unnecessary.
    2. Dietary exposure from drinking water. The Agency used screening 
level water exposure models in the dietary exposure analysis and risk 
assessment for mesotrione in drinking water. These simulation models 
take into account data on the physical, chemical, and fate/transport 
characteristics of mesotrione. 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 Pesticide Root Zone Model/Exposure Analysis Modeling 
System (PRZM/EXAMS) and Screening Concentration in Ground Water (SCI-
GROW) models for the experimental use permit issued for an experimental 
program with mesotrione on soybeans (100-EUP-114), the estimated 
drinking water concentrations (EDWCs) of mesotrione for chronic 
exposures are estimated to be 5.1 parts per billion (ppb) for surface 
water and 0.54 ppb for ground 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).
    Mesotrione is currently registered for the following uses that 
could result in residential exposures: Golf course, commercial and 
residential turf. EPA assessed residential exposure using the following 
assumptions: Residential adult handlers (dermal and inhalation) as well 
as postapplication exposure to adults (dermal), youths (dermal), and 
toddlers (dermal and incidental oral) to residues on treated grass was 
assessed.
    4. Cumulative effects from substances with a common mechanism of 
toxicity. Section 408(b)(2)(D)(v) of 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.''
    Mesotrione, pyrasulfotole, isoxaflutole and topramezone belong to a 
class of herbicides that inhibit the liver enzyme, 4-
hydroxyphenylpyruvate dioxygenase (HPPD), which is involved in the 
catabolism (metabolic breakdown) of tyrosine (an amino acid derived 
from proteins in the diet). Inhibition of HPPD can result in elevated 
tyrosine levels in the blood, a condition called tyrosinemia. HPPD-
inhibiting herbicides have been found to cause a number of toxicities 
in laboratory animal studies including ocular, developmental, liver and 
kidney effects. Of these toxicities, it is the ocular effect (corneal 
opacity) that is highly correlated with the elevated blood tyrosine 
levels. In fact, rats dosed with tyrosine alone show ocular opacities 
similar to those seen with HPPD inhibitors. Although the other 
toxicities may be associated with chemically-induced tyrosinemia, other 
mechanisms may also be involved.
    There are marked differences among species in the ocular toxicity 
associated with inhibition of HPPD. Ocular effects following treatment 
with HPPD inhibitor herbicides are seen in the rat but not in the 
mouse. Monkeys also seem to be recalcitrant to the ocular toxicity 
induced by HPPD inhibition. One explanation of this species-specific 
response in ocular opacity may be related to the species differences in 
the clearance of tyrosine. A metabolic pathway exists to remove 
tyrosine from the blood that involves a liver enzyme called tyrosine 
aminotransferase (TAT). In contrast to rats where ocular toxicity is 
observed following exposure to HPPD-inhibiting herbicides, mice and 
humans are unlikely to achieve the levels of plasma tyrosine necessary 
to produce ocular opacities because the activity of TAT in these 
species is much greater compared to rats. HPPD inhibitors (e.g., 
nitisinone) are used as an effective therapeutic agent to treat 
patients suffering from rare genetic diseases of tyrosine catabolism. 
Treatment starts in childhood but is often sustained throughout 
patient's lifetime. The human experience indicates that a therapeutic 
dose (1 mg/kg/day dose) of nitisinone has an excellent safety record in 
infants, children and adults and that serious adverse health outcomes 
have not been observed in a population followed for approximately a 
decade. Rarely, ocular effects are seen in patients with high plasma 
tyrosine levels; however, these effects are transient and can be 
readily reversed upon adherence to a restricted protein diet. This 
indicates that an HPPD inhibitor in and of itself cannot easily 
overwhelm the tyrosine-clearance mechanism in humans.
    Therefore, exposure to environmental residues of HPPD-inhibiting 
herbicides are unlikely to result in the high blood levels of tyrosine 
and ocular toxicity in humans due to an efficient metabolic process to 
handle excess tyrosine. The Agency continues to study the complex 
relationships between elevated tyrosine levels and biological effects 
in various species. Nonetheless, as a worst case scenario, EPA has 
assessed aggregate exposure to mesotrione based on ocular effects in 
rats. For similar reasons, a semi-quantitative screening cumulative 
assessment was conducted using the rat ocular effects and 100% crop 
treated information. The results of this screening analysis did not 
indicate a concern. In the future, assessments of HPPD-inhibiting 
herbicides will consider more appropriate models and cross species 
extrapolation methods. For additional 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 
EPA's website at http://www.epa.gov/pesticides/cumulative.

D. Safety Factor for Infants and Children

    1. In general. Section 408(b)(2)(C) of FFDCA provides that EPA 
shall apply an additional tenfold (10X) 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 database on toxicity 
and exposure unless EPA determines based on reliable data that a 
different margin of safety will be safe for infants and children. This 
additional margin of safety is commonly referred to as the FQPA SF. In 
applying this provision, EPA either retains the default value of 10X, 
or uses a different additional safety factor when reliable data 
available to EPA support the choice of a different factor.
    2. Prenatal and postnatal sensitivity. There is quantitative 
evidence of increased susceptibility of the young in the oral prenatal 
developmental toxicity studies in rats, mice, and rabbits and in the 
multi-generation reproduction study in mice. Quantitative evidence of 
increased susceptibility was not demonstrated in the multi-generation 
reproduction study in rats. The ocular discharge seen in the 
reproductive study in mice provided a highly conservative endpoint at 
7,000 ppm. There is a well characterized NOAEL protecting

[[Page 67122]]

offspring in the developmental and reproductive studies in mice 
(relevant species for human-health risk assessment). The endpoints and 
dose selected for the RfD, as well as incidental exposure assessments, 
will be protective of the effects seen in the developmental toxicity 
study in rabbits.
    3. Conclusion. EPA concluded that an additional FQPA SF is needed 
to address uncertainty due to reliance on a LOAEL from the mouse two-
generation reproduction study in establishing the POD for mesotrione. 
Nonetheless, EPA determined that there is reliable data showing that 
the default additional safety factor value of 10X can be safely reduced 
to 3X. This conclusion is based on the following:
    i. The toxicity database for mesotrione is complete, except for 
immunotoxicity testing and a deficiency in the mouse two-generation 
reproduction study (lack of a NOAEL). EPA began requiring functional 
immunotoxicity testing of all food and non-food use pesticides on 
December 26, 2007. These studies are not yet available for mesotrione. 
In the absence of specific immunotoxicity studies, EPA has evaluated 
the available mesotrione toxicity data to determine whether an 
additional database uncertainty factor is needed to account for 
potential immunotoxicity of mesotrione. There was no evidence of 
adverse effects on the organs of the immune system in any study with 
mesotrione. Based on these considerations, EPA does not believe that 
conducting a special test guideline series, 870.7800 immunotoxicity 
study will result in a point of departure less than the LOAEL of 2.1 
mg/kg/day used in calculating the cPAD for mesotrione; therefore, an 
additional database uncertainty factor is not needed to account for 
potential immunotoxicity.
    ii. The LOAEL used to establish the level of concern is based on 
tyrosineanemia in mice caused by excess tyrosine in the blood. 
Mesotrione can lead to excess tyrosine because it inhibits the liver 
enzyme HPPD which metabolically breaks down tyrosine. Tyrosine can also 
be removed from the blood by the activity of tyrosine aminotransferase 
(TAT). EPA reviewed comparative data on TAT in the rat, mouse and 
human, and concluded that the mouse and the human were similar in their 
ability to remove the excess tyrosine from the blood, while the rat was 
more limited in this ability and thus more sensitive to the effects of 
HPPD inhibition. Because a 10X interspecies factor has been retained 
despite evidence that the mouse is not less sensitive than humans to 
these effects, it is not necessary to retain the full tenfold FQPA 
factor to account for the use of a LOAEL from the mouse two-generation 
reproduction study. In effect, by not reducing the interspecies factor 
and retaining a 3X FQPA SF, EPA is retaining an additional SF for the 
protection of infants and children that is at least equal to 10X.
    iii. There is low concern for the susceptibility seen in the 
developmental studies in mice (relevant species for human health risk 
assessment) because there is a well characterized NOAEL protecting 
offspring in these studies. In the developmental toxicity study in New 
Zealand white rabbits and in rats, no NOAEL was established for the 
developmental effects. However, since the effects seen in the rabbits 
and rat studies were at much higher doses (twentyfold) than the dose 
used for establishing the POD, the POD is protective of the effects 
seen in the developmental toxicity studies in rats and rabbits.
    iv. Mesotrione exerts its toxicity via the inhibition of HPPD, 
causing the build-up of tyrosine levels in the blood. There are data in 
the published literature indicating that children with elevated plasma 
tyrosine levels during development due to a genetic disorder may have 
mental retardation or neurological symptoms. However, by protecting 
against the excessive build-up of tyrosine in the blood, the human 
health risk assessment is protective of all adult and child 
populations. Further, because the data show that any potential 
developmental neurotoxicity of mesotrione is related to the build-up of 
tyrosine in the blood and nervous tissues, it is not necessary to 
conduct a DNT study.
    v. There are no residual uncertainties identified in the exposure 
databases. The chronic dietary food exposure assessment utilizes 
proposed tolerance level residues and 100% crop treated for all 
commodities. EPA made conservative (protective) assumptions in the 
residue estimates used to assess exposure to mesotrione in drinking 
water. EPA used similarly conservative assumptions to assess 
postapplication exposure of children including incidental oral exposure 
of toddlers. These assessments will not underestimate the exposure and 
risks posed by mesotrione.

E. Aggregate Risks and Determination of Safety

    EPA determines whether acute and chronic pesticide exposures are 
safe by comparing aggregate exposure estimates to the aPAD and cPAD. 
The aPAD and cPAD represent the highest safe exposures, taking into 
account all appropriate SFs. EPA calculates the aPAD and cPAD by 
dividing the POD by all applicable UFs. For linear cancer risks, EPA 
calculates the probability of additional cancer cases given the 
estimated aggregate exposure. Short-, intermediate-, and chronic-term 
risks are evaluated by comparing the estimated aggregate food, water, 
and residential exposure to the POD to ensure that the MOE called for 
by the product of all applicable UFs is not exceeded.
    1. Acute risk. There were no effects observed in oral toxicity 
studies including developmental toxicity studies in rats and rabbits 
that could be attributable to a single dose (exposure). Therefore, 
mesotrione is not expected to pose an acute risk.
    2. Chronic risk. Using the exposure assumptions described in this 
unit for chronic exposure, EPA has concluded that chronic exposure to 
mesotrione from food and water will utilize 5.8% of the cPAD for (all 
infants less than 1 year old) the population group receiving the 
greatest exposure. Long-term aggregate risk was not calculated because 
residential post-application exposure over the long-term duration (more 
than 6 months) is not expected based on the potential residential use 
pattern of mesotrione.
    3. Short-term risk. Short-term aggregate exposure takes into 
account short-term residential exposure plus chronic exposure to food 
and water (considered to be a background exposure level).
    Mesotrione is currently registered for use on golf course, 
commercial and residential turf that could result in short-term 
residential exposure and the Agency has determined that it is 
appropriate to aggregate chronic exposure through food and water with 
short-term residential exposures to mesotrione. Residential handler 
(adult only) as well as postapplication exposure to adults, youths, and 
toddlers to residues on treated grass was assessed. A summary of the 
assumptions for residential handler (dermal and inhalation) and post 
application dermal and incidental oral (toddlers only) exposure from 
mesotrione use on turf grass can be found at http://www.regulations.gov 
in document ``Mesotrione: Human-Health Risk Assessment for Section 3 
New Uses on Soybeans'' at page 23 in docket ID number EPA-HQ-OPP-2006-
0811.
    Using the exposure assumptions described in this unit for short-
term exposures, EPA has concluded that the combined short-term food, 
water, and residential exposures aggregated result in aggregate MOEs of 
370 for toddlers,

[[Page 67123]]

6,000 for youth, and 2,600 for adults. As EPA's Level of Concern (LOC) 
of 300 for mesotrione is below these MOEs, they are not of concern.
    4. Intermediate-term risk. Intermediate-term aggregate exposure 
takes into account intermediate-term residential exposure plus chronic 
exposure to food and water (considered to be a background exposure 
level).
    Mesotrione is currently registered for use on residential turf 
grass that could result in intermediate-term residential exposure to 
toddlers from ingestion of treated soil and the Agency has determined 
that it is appropriate to aggregate chronic exposure to mesotrione 
through food and water with intermediate-term exposures for mesotrione.
    Using the exposure assumptions described in this unit for 
intermediate-term exposures, EPA has concluded that the combined 
intermediate-term food, water, and residential exposures aggregated 
result in aggregate MOE of 9,000 for toddlers. As EPA's LOC of 300 for 
mesotrione is below this MOE, it is not of concern.
    5. Aggregate cancer risk for U.S. population. Mesotrione is 
classified as ``not likely'' to be carcinogenic in humans based on the 
results of a carcinogenicity study in mice and the combined chronic 
toxicity and carcinogenicity study in the rat. Therefore, mesotrione is 
not expected to pose a cancer risk to humans.
    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 or to infants and children from aggregate 
exposure to mesotrione residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    Adequate enforcement methodology, high-pressure liquid 
chromatography fluorescence detector (HPLC/FLD), is available to 
enforce the tolerance expression. The method may be requested from: 
Chief, Analytical Chemistry Branch, Environmental Science Center, 701 
Mapes Rd., Ft. Meade, MD 20755-5350; telephone number: (410) 305-2905; 
e-mail address: residuemethods@epa.gov.

B. International Residue Limits

    There are no CODEX, Canadian, or Mexican tolerances/Maximum Residue 
Levels (MRLs) for mesotrione residues for the proposed crop. Thus, 
harmonization is not an issue at this time.

V. Conclusion

    Therefore, a tolerance is established for residues of the 
herbicide, mesotrione, including its metabolites and degradates, in or 
on soybean, seed at 0.01 ppm. Compliance with the tolerance level is to 
be determined by measuring only mesotrione, 2-[4-(methylsulfonyl)-2-
nitrobenzoyl]-1,3-cyclohexanedione, in the raw agricultural commodity.

VI. Statutory and Executive Order Reviews

    This final rule establishes tolerances 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 final rule has been 
exempted from review under Executive Order 12866, this final rule is 
not subject to Executive Order 13211, entitled Actions Concerning 
Regulations That Significantly Affect Energy Supply, Distribution, or 
Use (66 FR 28355, May 22, 2001) or Executive Order 13045, entitled 
Protection of Children from Environmental Health Risks and Safety Risks 
(62 FR 19885, April 23, 1997). 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., 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).
    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.
    This final rule directly regulates growers, food processors, food 
handlers, and food retailers, not States or tribes, nor does this 
action alter the relationships or distribution of power and 
responsibilities established by Congress in the preemption provisions 
of section 408(n)(4) of FFDCA. As such, the Agency has determined that 
this action will not have a substantial direct effect on States or 
tribal governments, on the relationship between the national government 
and the States or tribal governments, or on the distribution of power 
and responsibilities among the various levels of government or between 
the Federal Government and Indian tribes. Thus, the Agency has 
determined that Executive Order 13132, entitled Federalism (64 FR 
43255, August 10, 1999) and Executive Order 13175, entitled 
Consultation and Coordination with Indian Tribal Governments (65 FR 
67249, November 9, 2000) do not apply to this final rule. In addition, 
this final rule does not 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).
    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).

VII. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report 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: December 8, 2009.
Lois Rossi,
Director, Registration Division, Office of Pesticide Programs.

0
Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

0
1. The authority citation for part 180 continues to read as follows:

    Authority: 21 U.S.C. 321(q), 346a and 371.

0
2. Section 180.571 is amended by revising introductory text of 
paragraph (a) and by alphabetically adding the commodity ``soybean, 
seed'' to the table in paragraph (a) to read as follows:

[[Page 67124]]

Sec.  180. 571  Mesotrione; tolerances for residues.

    (a) General. Tolerances are established for residues of the 
herbicide mesotrione, including its metabolites and degradates, in or 
on the commodities in the table below. Compliance with the tolerance 
levels specified below is to be determined by measuring only 
mesotrione, 2-[4-(methylsulfonyl)-2-nitrobenzoyl]-1,3-cyclohexanedione, 
in or on the following raw agricultural commodities:

----------------------------------------------------------------------------------------------------------------
                       Commodity                                            Parts per million
----------------------------------------------------------------------------------------------------------------
                                                    * * * * *
Soybean, seed.........................................                                                      0.01
                                                    * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *
[FR Doc. E9-30034 Filed 12-17-09; 8:45 am]

BILLING CODE 6560-50-S