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[Federal Register Volume 76, Number 159 (Wednesday, August 17, 2011)]
[Rules and Regulations]
[Pages 50898-50904]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-20841]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2010-0621; FRL-8882-7]

Metconazole; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for residues of 
metconazole in or on the bushberry subgroup 13-07B and the tuberous and 
corm vegetable subgroup 1C. The Interregional Research Project No. 4 
(IR-4) requested these tolerances under the Federal Food, Drug, and 
Cosmetic Act (FFDCA).

DATES: This regulation is effective August 17, 2011. Objections and 
requests for hearings must be received on or before October 17, 2011, 
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-2010-0621. 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: Andrew Ertman, Registration Division 
(7505P), Office of Pesticide Programs, Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 308-9367; e-mail address: ertman.andrew@epa.gov.

[[Page 50899]]

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 Get electronic access to other related information?

    You may access a frequently updated electronic version of EPA's 
tolerance regulations at 40 CFR part 180 through the Government 
Printing Office's e-CFR site at http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?&c=ecfr&tpl=/ecfrbrowse/Title40/40tab_02.tpl. To access the 
harmonized test guidelines referenced in this document electronically, 
please go http://www.epa.gov/ocspp and select ``Test Methods and 
Guidelines.''

C. How can I file an objection or hearing request?

    Under FFDCA section 408(g), 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-2010-0621 in the subject line on the first 
page of your submission. All objections and requests for a hearing must 
be in writing, and must be received by the Hearing Clerk on or before 
October 17, 2011. Addresses for mail and hand delivery of objections 
and hearing requests are provided in 40 CFR 178.25(b).
    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. Information not marked confidential pursuant to 40 CFR part 2 
may be disclosed publicly by EPA without prior notice. Submit a copy of 
your non-CBI objection or hearing request, identified by docket ID 
number EPA-HQ-OPP-2010-0621, 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. Summary of Petitioned-For Tolerance

    In the Federal Register of September 8, 2010 (75 FR 54629) (FRL-
8843-3), 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 
0E7743) by Interregional Research Project Number 4 (IR-4) Project 
Headquarters, Rutgers, The State University of New Jersey, 500 College 
Road East, Suite 201 W, Princeton, NJ 08450. The petition requested 
that 40 CFR 180.617 be amended by establishing tolerances for residues 
of the fungicide metconazole, 5-[(4-chlorophenyl)-methyl]-2,2-dimethyl-
1-(1 H -1,2,4-triazol-1-ylmethyl) cyclopentanol), measured as the sum 
of cis- and trans isomers, in or on bushberry subgroup 13-07B at 0.35 
parts per million (ppm); and tuberous and corm vegetable subgroup 1C at 
0.02 ppm. That notice referenced a summary of the petition prepared by 
Valent, the registrant, which is available in the docket, http://www.regulations.gov. There were no comments received in response to the 
notice of filing.
    Based upon review of the data supporting the petition, EPA has 
modified the levels at which tolerances are being established for the 
tuberous and corm vegetables subgroup 1C and the bushberry subgroup 13-
07B. Additionally, the commodity definition for the tuberous and corm 
vegetables subgroup 1C is being corrected. The reasons for these 
changes are explained in Unit IV.C.

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 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 metconazole including 
exposure resulting from the tolerances established by this action. 
EPA's assessment of exposures and risks associated with metconazole 
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.
    Acute oral and dermal toxicities to metconazole are moderate, while 
acute inhalation toxicity is low. Metconazole is a moderate eye 
irritant and a mild skin irritant. It is not a skin sensitizer. The 
liver is the primary target organ in the mouse, rat and dog following 
oral exposure to metconazole via subchronic or chronic exposure 
durations. Developmental studies in rats and

[[Page 50900]]

rabbits show some evidence of developmental effects, but only at dose 
levels that are maternally toxic. Metconazole did not demonstrate the 
potential for neurotoxicity in the four species (mouse, rat, dog and 
rabbit) tested. Metconazole is considered non-genotoxic and liver 
tumors seen in a chronic mouse study appear to have been formed via a 
mitogenic mode of action and therefore, metconazole is classified as 
``not likely to be carcinogenic to humans'' at levels that do not cause 
mitogenesis. There was no evidence of immunotoxicity at dose levels 
that produced systemic toxicity. No immunotoxic effects are evident for 
metconazole at dose levels as high as 52 milligrams/kilogram/day (mg/
kg/day) in rats, which is 12 times higher than the chronic dietary 
point of departure (4.3 mg/kg/day). Metconazole did not demonstrate 
neurotoxicity in the subchronic neurotoxicity study or the other 
submitted studies including acute, subchronic and chronic studies in 
several species, developmental toxicity studies in the rat and rabbit 
and a 2-generation reproduction study in the rat. No effects were noted 
on brain weights and no clinical signs possibly related to 
neurotoxicity were noted up to and including the high doses in all 
studies.
    Specific information on the studies received and the nature of the 
adverse effects caused by metconazole 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 docket ID number EPA-HQ-OPP-2010-0621 on pages 
44-50 of the document titled ``Metconazole: Human Health Risk 
Assessment for Proposed Uses on Tuberous and Corm Vegetables Subgroup 
1C and Bushberry Subgroup 13-07B.''

B. Toxicological Points of Departure/Levels of Concern

    Once a pesticide's toxicological profile is determined, EPA 
identifies toxicological points of departure (POD) and levels of 
concern (LOC) to use in evaluating the risk posed by human exposure to 
the pesticide. For hazards that have a threshold below which there is 
no appreciable risk, the toxicological POD is used as the basis for 
derivation of reference values for risk assessment. PODs are developed 
based on a careful analysis of the doses in each toxicological study to 
determine the dose at which no adverse effects are observed (the NOAEL) 
and the lowest dose at which adverse effects of concern are identified 
(the LOAEL). Uncertainty/safety factors are used in conjunction with 
the POD to calculate a safe exposure level--generally referred to as a 
population-adjusted dose (PAD) or a reference dose (RfD)--and a safe 
margin of exposure (MOE). 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 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 metconazole used for 
human risk assessment is shown in Table 1 of this unit.

  Table 1--Summary of Toxicological Doses and Endpoints for Metconazole for Use in Human Health Risk Assessment
----------------------------------------------------------------------------------------------------------------
                                        Point of departure and
          Exposure/scenario               uncertainty/safety    RfD, PAD, LOC for  risk  Study and toxicological
                                               factors                 assessment                effects
----------------------------------------------------------------------------------------------------------------
Acute Dietary (General Population,     An appropriate dose/endpoint attributable to a single dose was not
 including Infants and Children).       observed in the available oral toxicity studies reviewed.
----------------------------------------------------------------------------------------------------------------
Acute dietary (Females 13-49 years of  NOAEL = 12 mg/kg/day...  Acute RfD = 0.12 mg/kg/  Developmental toxicity
 age).                                 UFA = 10x..............   day.                     in rats: LOAEL = 30 mg/
                                       UFH = 10x..............  aPAD = 0.12 mg/kg/day..   kg/day based on
                                       FQPA SF = 1x...........                            increases in skeletal
                                                                                          variations.
Chronic dietary (All populations)....  NOAEL = 4.3 mg/kg/day..  Chronic RfD = 0.04 mg/   Chronic oral toxicity
                                       UFA = 10x..............   kg/day.                  study in rats: LOAEL =
                                       UFH = 10x..............  cPAD = 0.04 mg/kg/day..   13.1 mg/kg/day based
                                       FQPA SF = 1x...........                            on increased liver
                                                                                          Males (M) weights and
                                                                                          associated
                                                                                          hepatocellular lipid
                                                                                          vacuolation (M) and
                                                                                          centrilobular
                                                                                          hypertrophy (M).
                                                                                          Similar effects were
                                                                                          observed in Females
                                                                                          (F) at 54 mg/kg/day,
                                                                                          plus increased spleen
                                                                                          weight.
Incidental oral short-term (1 to 30    NOAEL = 9.1 mg/kg/day..  LOC for MOE = 100......  28-Day oral toxicity
 days).                                UFA = 10x..............                            study in rats: LOAEL =
                                       UFH = 10x..............                            90.5 mg/kg/day based
                                       FQPA SF = 1x...........                            on decreased body
                                                                                          weight (M), increased
                                                                                          liver and kidney
                                                                                          weight and
                                                                                          hepatocellular
                                                                                          hypertrophy and
                                                                                          vacuolation (M/F).
Incidental oral intermediate-term (1   NOAEL= 6.4 mg/kg/day...  LOC for MOE = 100......  90-Day oral toxicity
 to 6 months).                         UFA = 10x..............                            study in rats: LOAEL =
                                       UFH = 10x..............                            19.2 mg/kg/day based
                                       FQPA SF = 1x...........                            on increased spleen wt
                                                                                          (F) and hepatic
                                                                                          vacuolation (M).
Inhalation short-term (1 to 30 days).  NOAEL= 9.1 mg/kg/day...  LOC for MOE = 100......  28-Day oral toxicity
                                       UFA = 10x..............                            study in rats: LOAEL =
                                       UFH = 10x..............                            90.5 mg/kg/day based
                                       FQPA SF = 1x...........                            on decreased body
                                                                                          weight (M), increased
                                                                                          liver and kidney
                                                                                          weight and
                                                                                          hepatocellular
                                                                                          hypertrophy and
                                                                                          vacuolation (M/F).

[[Page 50901]]

 
Inhalation (1 to 6 months)...........  NOAEL= 6.4 mg/kg/day...  LOC for MOE = 100......  90-Day oral toxicity
                                       UFA = 10x..............                            study in rats: LOAEL =
                                       UFH = 10x..............                            19.2 mg/kg/day based
                                       FQPA SF = 1x...........                            on increased spleen wt
                                                                                          (F) and hepatic
                                                                                          vacuolation (M).
----------------------------------------------------------------------------------------------------------------
Cancer (Oral, dermal, inhalation)....  Classification: ``Not likely to be Carcinogenic to Humans.''
----------------------------------------------------------------------------------------------------------------
UFA = extrapolation from animal to human (interspecies). UFH = potential variation in sensitivity among members
  of the human population (intraspecies). FQPA SF = Food Quality Protection Act Safety Factor. PAD = population
  adjusted dose (a = actue, c = chronic). RfD = reference dose. MOE = margin of exposure. LOC = level of
  concern.

C. Exposure Assessment

    1. Dietary exposure from food and feed uses. In evaluating dietary 
exposure to metconazole, EPA considered exposure under the petitioned-
for tolerances as well as all existing metconazole tolerances in 40 CFR 
180.617. EPA assessed dietary exposures from metconazole 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 
metconazole for the general U.S. population including infants and 
children; therefore, a quantitative acute dietary exposure assessment 
is unnecessary for these population subgroups. However, such effects 
were identified for metconazole for females 13-49 years of age. In 
estimating acute dietary exposure, EPA used food consumption 
information from the United States Department of Agriculture (USDA) 
1994-1996 and 1998 Nationwide Continuing Surveys of Food Intake by 
Individuals (CSFII). As to residue levels in food, EPA assumed that 
metconazole residues are present in all registered and proposed food 
commodities at tolerance levels and that 100% of the crops were 
treated.
    ii. Chronic exposure. In conducting the chronic dietary exposure 
assessment EPA used the food consumption data from the USDA 1994-1996 
and 1998 CSFII. As to residue levels in food, EPA assumed that 
metconazole residues are present in all registered and proposed food 
commodities at tolerance levels and that 100% of the crops were 
treated.
    iii. Cancer. Based on the data summarized in Unit III.A., EPA has 
concluded that metconazole does not pose a cancer risk to humans. 
Therefore, a dietary exposure assessment for the purpose of assessing 
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 metconazole in drinking water. These simulation models 
take into account data on the physical, chemical, and fate/transport 
characteristics of metconazole. 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 the estimated drinking water concentrations (EDWCs) of 
metconazole for acute exposures are estimated to be 45.48 parts per 
billion (ppb) for surface water and 0.064 ppb for ground water. For 
chronic exposures for non-cancer assessments they are estimated to be 
38.16 ppb for surface water and 0.064 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 45.48 ppb was used to 
assess the contribution to drinking water.
    For chronic dietary risk assessment, the water concentration of 
value 38.16 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). Metconazole is 
currently registered for the following uses that could result in 
residential exposures: Turf and ornamentals. EPA assessed residential 
exposure using the following assumptions: Adults, adolescents, and 
children may be exposed to metconazole from its currently registered 
uses on turf and ornamentals. No dermal toxicity endpoints for short- 
and intermediate-term durations were identified up to the limit dose. 
Therefore, only residential handler and postapplication inhalation 
exposures for adults, and residential post-application incidental oral 
exposures for children have been assessed. For adults applying 
metconazole to turf, short- and intermediate-term exposures were 
assessed for mixer/loader/applicators with a low pressure handwand 
sprayer. Post-application risks to children following the application 
of metconazole to home lawns were calculated for short- and 
intermediate-term incidental oral exposures. Further information 
regarding EPA standard assumptions and generic inputs for residential 
exposures may be found at http://www.epa.gov/pesticides/trac/science/trac6a05.pdf.
    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.''
    Metconazole is a member of the triazole-containing class of 
pesticides. Although conazoles act similarly in plants (fungi) by 
inhibiting ergosterol biosynthesis, there is not necessarily a 
relationship between their pesticidal activity and their mechanism of 
toxicity in mammals. Structural similarities do not constitute a common 
mechanism of toxicity. Evidence is needed to establish that the 
chemicals operate by the same, or essentially the same, sequence of 
major biochemical events. In conazoles, however, a variable pattern of 
toxicological responses is found. Some are hepatotoxic and 
hepatocarcinogenic in mice. Some induce thyroid tumors in

[[Page 50902]]

rats. Some induce developmental, reproductive, and neurological effects 
in rodents. Furthermore, the conazoles produce a diverse range of 
biochemical events including altered cholesterol levels, stress 
responses, and altered DNA methylation. It is not clearly understood 
whether these biochemical events are directly connected to their 
toxicological outcomes. Thus, there is currently no evidence to 
indicate that conazoles share common mechanisms of toxicity and EPA is 
not following a cumulative risk approach based on a common mechanism of 
toxicity for the conazoles. For information regarding EPA's procedures 
for cumulating effects from substances found to have a common mechanism 
of toxicity, see EPA's Web site at http://www.epa.gov/pesticides/cumulative.
    Metconazole is a triazole-derived pesticide. Triazole-derived 
pesticides can form the common metabolite, 1,2,4-triazole and three 
triazole conjugates (triazole alanine, triazole acetic acid, and 
triazolylpyruvic acid). To support existing tolerances and to establish 
new tolerances for triazole-derivative pesticides, including 
metconazole, EPA conducted a human health risk assessment for exposure 
to 1,2,4-triazole, triazole alanine, and triazole acetic acid resulting 
from the use of all current and pending uses of any triazole-derived 
fungicide. The risk assessment is a highly conservative, screening-
level evaluation in terms of hazards associated with common metabolites 
(e.g., use of a maximum combination of uncertainty factors) and 
potential dietary and non-dietary exposures (i.e., high end estimates 
of both dietary and non-dietary exposures). In addition, the Agency 
retained the additional 10X FQPA SF for the protection of infants and 
children. The assessment included evaluations of risks for various 
subgroups, including those comprised of infants and children. The 
Agency's risk assessment can be found in the propiconazole 
reregistration docket at http://www.regulations.gov, Docket 
Identification Number EPA-HQ-OPP- 2005-0497 and an update to assess the 
addition of the commodities included in this action may be found in 
docket ID number EPA-HQ-OPP-2010-0621 in the document titled ``Common 
Triazole Metabolites: Updated Aggregate Human Health Risk Assessment To 
Address Tolerance Petitions for Metconazole.''

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. Acceptable developmental 
toxicity studies are available in the rat and rabbit as well as a 2-
generation reproductive toxicity study in the rat. There is no evidence 
of susceptibility following in utero exposure in the rabbit. In the rat 
there is qualitative evidence of susceptibility, however the concern is 
low since the developmental effects are characterized as variations 
(not malformations), occur in the presence of maternal toxicity, the 
NOAELs are well defined, and the dose/endpoint is used for acute 
dietary risk assessment for the sensitive population. There is no 
evidence of increased susceptibility in the offspring based on the 
result of the 2-generation reproduction study.
    3. Conclusion. EPA has determined that reliable data show the 
safety of infants and children would be adequately protected if the 
FQPA SF were reduced to 1x. That decision is based on the following 
findings:
    i. The toxicity database for metconazole is complete except for a 
neurotoxicity study. Changes to 40 CFR 180.158 make the acute 
neurotoxicity testing (OPPTS Guideline 870.6200) required for pesticide 
registration. Although this study is not yet available for metconazole, 
the available data do not show any evidence of neurotoxicity. 
Metconazole did not demonstrate neurotoxicity in the subchronic 
neurotoxicity study or the other submitted studies including acute, 
subchronic and chronic studies in several species, developmental 
toxicity studies in the rat and rabbit and a 2-generation reproduction 
study in the rat. No effects were noted on brain weights and no 
clinical signs possibly related to neurotoxicity were noted up to and 
including the high doses in all studies. Therefore, EPA does not 
believe that conducting the acute neurotoxicity study will result in an 
endpoint lower than the ones used in risk assessment for metconazole. 
Consequently, an additional database uncertainty factor does not need 
to be applied.
    ii. There is no evidence of susceptibility following in utero 
exposure in the rabbit. In the rat there is qualitative evidence of 
susceptibility, however the concern is low since the developmental 
effects are characterized as variations (not malformations), occur in 
the presence of maternal toxicity, the NOAELs are well defined, and the 
dose/endpoint is used for acute dietary risk assessment for the 
sensitive population. There is no evidence of increased susceptibility 
in the offspring based on the result of the 2-generation reproduction 
study.
    iii. There are no residual uncertainties identified in the exposure 
databases. The dietary food exposure assessments were performed based 
on 100 percent crop treated and tolerance-level residues. EPA made 
conservative (protective) assumptions in the ground and surface water 
modeling used to assess exposure to metconazole in drinking water. EPA 
used similarly conservative assumptions to assess postapplication 
exposure of children as well as incidental oral exposure of toddlers. 
These assessments will not underestimate the exposure and risks posed 
by metconazole.

E. Aggregate Risks and Determination of Safety

    EPA determines whether acute and chronic dietary pesticide 
exposures are safe by comparing aggregate exposure estimates to the 
aPAD and cPAD). For linear cancer risks, EPA calculates the lifetime 
probability of acquiring cancer 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 appropriate PODs to ensure that an adequate MOE exists.
    1. Acute risk. Using the exposure assumptions discussed in this 
unit for acute exposure, the acute dietary exposure from food and water 
to metconazole will occupy 3.8% of the aPAD for females 13-49, the only 
population subgroup of concern.
    2. Chronic risk. Using the exposure assumptions described in this 
unit for chronic exposure, EPA has concluded that chronic exposure to 
metconazole from food and water will utilize 12.6% of the cPAD for 
children 1-2 years old, the population group receiving the greatest 
exposure. Based on the explanation in Unit III.C.3., regarding 
residential use patterns, chronic residential exposure to residues of 
metconazole is not expected.
    3. Short- and intermediate-term risk. Short- and intermediate-term 
aggregate exposure takes into account short- and

[[Page 50903]]

intermediate-term residential exposure plus chronic exposure to food 
and water (considered to be a background exposure level).
    Metconazole is currently registered for uses that could result in 
short- and intermediate-term residential exposure, and the Agency has 
determined that it is appropriate to aggregate chronic exposure through 
food and water with short- and intermediate-term residential exposures 
to metconazole.
    Using the exposure assumptions described in this unit for short- 
and intermediate-term exposures, EPA has concluded, that the short-and 
intermediate-term aggregate MOEs from dietary exposure (food + drinking 
water) and non-occupational/residential handler exposure (inhalation) 
for adults are 1,700 for both.
    The short-and intermediate-term aggregate MOEs from dietary 
exposure (food + drinking water) and non-occupational/residential post-
application exposure (incidental oral) for children 1-2 years old are 
420 and 460, respectively. Because EPA's level of concern for 
metconazole is a MOE of 100 or below, these MOEs are not of concern.
    4. Aggregate cancer risk for U.S. population. Based on the lack of 
evidence of carcinogenicity in two adequate rodent carcinogenicity 
studies, metconazole is not expected to pose a cancer risk to humans.
    5. 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 metconazole residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    An adequate gas chromatography method with nitrogen-phosphorus-
detection (GC/NPD) is available for data collection and enforcement of 
tolerances for residues of metconazole parent isomers (cis- and trans-
metconazole) in plant commodities based on Valent Method RM-41C-1, 
``Determination of cis and trans-Metconazole in Crops.'' An adequate 
high performance liquid chromatography (HPLC) method is available for 
data collection and enforcement of tolerances for residues of 1,2,4-
triazole (T), triazole alanine (TA), and triazole acetic acid (TAA). 
The methods 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

    In making its tolerance decisions, EPA seeks to harmonize U.S. 
tolerances with international standards whenever possible, consistent 
with U.S. food safety standards and agricultural practices. EPA 
considers the international maximum residue limits (MRLs) established 
by the Codex Alimentarius Commission (Codex), as required by FFDCA 
section 408(b)(4). The Codex Alimentarius is a joint U.N. Food and 
Agriculture Organization/World Health Organization food standards 
program, and it is recognized as an international food safety 
standards-setting organization in trade agreements to which the United 
States is a party. EPA may establish a tolerance that is different from 
a Codex MRL; however, FFDCA section 408(b)(4) requires that EPA explain 
the reasons for departing from the Codex level.
    The Codex has not established a MRL for metconazole on potato or 
blueberry or the respective crop subgroups.

C. Revisions to Petitioned-For Tolerances

    IR-4 proposed establishing tolerances on the bushberry subgroup 13-
07B at 0.35 ppm and the tuberous and corm vegetable subgroup 1C at 0.02 
ppm. Upon review, these levels are being revised to 0.40 ppm and 0.04 
ppm, respectively. EPA used the tolerance spreadsheet in the Agency's 
Guidance for Setting Pesticide Tolerances Based on Field Trial Data to 
determine the appropriate tolerance level for bushberries. The 
tolerance spreadsheet was not used to calculate the tolerance for 
tuberous and corm vegetables because residues in potatoes were below 
the LOQ (pre>
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