[Federal Register Volume 77, Number 187 (Wednesday, September 26, 2012)]
[Rules and Regulations]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2012-23738]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
Glufosinate Ammonium; Pesticide Tolerances
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
SUMMARY: This regulation establishes tolerances for residues of
glufosinate ammonium in or on multiple commodities which are identified
and discussed later in this document. Interregional Research Project
Number 4 (IR-4) and Bayer CropScience requested these tolerances under
the Federal Food, Drug, and Cosmetic Act (FFDCA).
DATES: This regulation is effective September 26, 2012 except for the
addition of the tolerance for Fruit, stone, group 12-12 to the table in
Sec. 180.473 (a), which is effective October 22, 2012. Objections and
requests for hearings must be received on or before November 26, 2012,
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: The docket for this action, identified by docket
identification (ID) number EPA-HQ-OPP-2009-0813, is available at http://www.regulations.gov or at the Office of Pesticide Programs Regulatory
Public Docket (OPP Docket) in the Environmental Protection Agency
Docket Center (EPA/DC), EPA West Bldg., Rm. 3334, 1301 Constitution
Ave. NW., Washington, DC 20460-0001. The Public Reading Room is open
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal
holidays. The telephone number for the Public Reading Room is (202)
566-1744, and the telephone number for the OPP Docket is (703) 305-
5805. Please review the visitor instructions and additional information
about the docket available at http://www.epa.gov/dockets.
FOR FURTHER INFORMATION CONTACT: Sidney Jackson, Registration Division
(7505P), Office of Pesticide Programs, Environmental Protection Agency,
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone
number: (703) 305-7610; email address: email@example.com.
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.
The following list of North American Industrial Classification System
(NAICS) codes is not intended to be exhaustive, but rather provides a
guide to help readers determine whether this document applies to them.
Potentially affected entities may include:
Crop production (NAICS code 111).
Animal production (NAICS code 112).
Food manufacturing (NAICS code 311).
Pesticide manufacturing (NAICS code 32532).
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.
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-2009-0813 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
November 26, 2012. 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 (excluding 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 the non-
CBI copy of your objection or hearing request, identified by docket ID
number EPA-HQ-OPP-2009-0813, by one of the following methods:
Federal eRulemaking Portal: http://www.regulations.gov.
Follow the online instructions for submitting comments. Do not submit
electronically any information you consider to be Confidential Business
Information (CBI) or other information whose disclosure is restricted
Mail: OPP Docket, Environmental Protection Agency Docket
Center (EPA/DC), (28221T), 1200 Pennsylvania Ave. NW., Washington, DC
Hand Delivery: To make special arrangements for hand
delivery or delivery of boxed information, please follow the
instructions at http://www.epa.gov/dockets/contacts.htm.
Additional instructions on commenting or visiting the docket, along
with more information about dockets generally, is available at http://www.epa.gov/dockets.
II. Summary of Petitioned-for Tolerance
In the Federal Registers of January 6, 2010 (75 FR 864) (FRL-8801-
5) and March 19, 2010 (75 FR 13277) (FRL-8813-2), EPA issued notices
pursuant to FFDCA section 408(d)(3), 21 U.S.C. 346a(d)(3), announcing
the filing of pesticide petitions; (PP 9E7604) by Interregional
Research Project Number 4 (IR-4), IR-4 Project Headquarters, 500
College Road East, Suite 201 W, Princeton, NJ 08540 and (PP 9F7655) by
Bayer CropScience LP, 2 T. W. Alexander Drive, Research Triangle Park,
NC 27709, respectively. The petitions requested that 40 CFR 180.473 be
amended by establishing tolerances for residues of the herbicide
glufosinate ammonium, butanoic acid, 2-amino-4-
(hydroxymethylphosphinyl)- monoammonium salt, and its metabolites, 2-
acetylamino-4-methylphosphinico-butanoic acid and 3-methylphosphinico-
propionic acid, calculated as the stoichiometric equivalent of 2-amino-
4-(hydroxymethylphosphinyl), in or on corn, sweet, forage at 4.0 parts
per million (ppm); corn, sweet, kernel plus cob with husks removed at
0.2 ppm; corn, sweet, stover at 6.0 ppm (PP 9E7604); citrus, fruit
(crop group 10) at 0.05 ppm; olives at 0.05 ppm; pome, fruit (crop
group 11) at 0.10 ppm; and stone fruit (crop group 12) at 0.10 ppm (PP
9F7655). These notices referenced a summary of the petition prepared by
Bayer CropScience LP, 2 T. W. Alexander Drive, Research Triangle Park,
NC 27709, the registrant, which is available in the docket, http://www.regulations.gov. There were no comments received in response to the
notices of filing.
Based upon review of the data supporting the petition, EPA is: (1)
Correcting certain crop definitions to comply with current Agency
policies; (2) establishing tolerance levels for certain commodities
other than the proposed levels; (3) removing the proposed tolerance for
plum, prune, dried; (4) modifying the crop group tolerances requested
to the revised and expanded citrus fruit group 10-10, pome fruit group
11-10 and stone fruit group 12-12; and 5) revising the tolerance
expression for all established commodities to be consistent with
current Agency policy. 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 FFDCA section 408(b)(2)(D), and the factors
specified in FFDCA section 408(b)(2)(D), EPA has reviewed the available
scientific data and other relevant information in support of this
action. EPA has sufficient data to assess the hazards of and to make a
determination on aggregate exposure for glufosinate ammonium including
exposure resulting from the tolerances established by this action.
EPA's assessment of exposures and risks associated with glufosinate
A. Toxicological Profile
EPA has evaluated the available toxicity data and considered their
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
Technical grade glufosinate ammonium has low toxicity in the oral,
dermal, inhalation studies and is not an eye or dermal irritant or a
Subchronic toxicity studies in rats showed inhibition of glutamate
synthetase and lead the Agency to conclude that the changes in brain
glutamine synthetase activity are of significant concern for possible
neurotoxicity and/or expression of clinical signs. Observed alterations
in liver and kidney glutamate synthetase are considered an adaptive
response. The primary effects in the mouse subchronic study were
increased liver and kidney weights with increases in serum aspartate
amino transferase and alkaline phosphatase.
Additional toxicity testing was conducted with the L-isomer of
glufosinate ammonium, and degradates glufosinate propanoic acid (MPP),
and 2-acetamido-4-methylphosphinico-butanoic acid (NAG). These
compounds, tested in subchronic rat, mouse, and dog studies, and in
developmental toxicity studies in rat and rabbit, are generally less
toxic than the parent compound. However, L-isomer of glufosinate
ammonium was found to be slightly more toxic than the racemic parent
compound. This finding is not concern since this isomer is included in
the toxicity testing of the parent compound at the levels in the
In chronic studies in the rat, inhibition of brain glutamine
synthetase, increased mortality, and increased occurrence of retinal
atrophy were noted, as were increased liver and kidney weights. In the
mouse, increased mortality was noted, as were changes in glucose levels
consistent with changes in glutathione levels. Increased mortality and
electrocardiogram alterations were observed in dogs. The developmental
toxicity study in the rat produced dilated renal pelvis and/or
hydroureter in the fetuses at levels that produced significant
increases in hyperactivity and vaginal bleeding in dams. In the rabbit,
decreased fetal body weight and increased mortality were observed at 20
milligrams/kilogram/day (mg/kg/day), while in rabbit dams, decreased
food consumption, body weight, and body weight gain were observed at 20
mg/kg/day. Since increased fetal mortality was observed in the presence
of less severe maternal
toxicity in the rabbit developmental study, there is evidence of
qualitative increased susceptibility in fetuses.
The reproductive toxicity study in rats indicated postnatal
developmental toxicity at the highest dose tested in the form of
decrease in viable pups. No parental toxicity was seen at the highest
dose tested. Since pup mortality was observed in the absence of
parental toxicity, there is evidence of quantitative increased
susceptibility in offspring.
There were indications of neurotoxicity in several studies. Of
particular concern is that the developmental neurotoxicity study
demonstrated alterations in brain morphometrics in the adult offspring
exposed in utero or during lactation at dose levels not associated with
maternal toxicity. Retinal atrophy was observed in a rat oral study. In
the 90-day dietary neurotoxicity study, increases in the incidence of
decreased exploratory activity, decreased alertness, and decreased
startle response, increased incidence of fearfulness, increased pain
response and meiosis were reported. The subchronic dermal toxicity
study indicated aggressive behavior, a high startle response and
piloerection. The 28-day subchronic inhalation study demonstrated tono-
clonic convulsions at the high dose in at least some males. However, in
a 37-day dietary neurotoxicity study, there was no evidence of
neurotoxicity at doses up to 143.3 mg/kg/day. There was no evidence of
neurotoxicity in two acute neurotoxicity studies at doses up to 500 mg/
kg/day. Also, there was no evidence of neurotoxicity in White Leghorn
hens following an acute dose of up to 10,000 mg/kg. Changes in
glutamine synthetase levels were observed in liver, kidney, and brain
in rats. The altered electrocardiograms seen in the dog studies imply a
possible neuromuscular effect.
There is no concern for immunotoxicity based on an adequate
There is no concern for mutagenic activity in several available
studies including: Salmonella E. Coli, in vitro mammalian cell gene
mutation assays, mammalian cell chromosome aberration assays, in vivo
mouse bone marrow micronucleus assays, and unscheduled DNA synthesis
Glufosinate ammonium was classified as ``not likely to be a human
carcinogen.'' There was no evidence of a treatment-related increase in
tumors in either rats or mice.
Specific information on the studies received and the nature of the
adverse effects caused by glufosinate ammonium 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 document ``Glufosinate Ammonium. Updated Human
Health Risk Assessment for the Proposed New Use of Glufosinate Ammonium
in/on Citrus Fruit (Crop Group 10), Pome Fruit (Crop Group 11), Stone
Fruit (Crop Group 12), Olives and Sweet Corn'', dated July 25, 2012 at
page number 34 in docket ID number EPA-HQ-OPP-2009-0813.
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 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 glufosinate ammonium
used for human risk assessment is shown in the following Table.
Table--Summary of Toxicological Doses and Endpoints for Glufosinate Ammonium for use in Human Health Risk
Point of departure
Exposure/Scenario and uncertainty/ RfD, PAD, LOC for Study and toxicological effects
safety factors risk assessment
Acute Dietary (General No endpoint attributable to a single exposure was identified for the general
Population, including Infants population, including infants and children.
Acute dietary (Females 13-50 NOAEL = 6.3 mg/kg/ aRfD = 0.063 mg/kg/ Developmental Toxicity Study in
years of age). day. day. Rabbits.
UFA = 10x........... aPAD = 0.063 mg/kg/ LOAEL = 20 mg/kg/day based on
UFH = 10x........... day. increased fetal deaths.
FQPA SF = 1x........
Chronic dietary (All populations) NOAEL = 6 mg/kg/day. cRfD = cPAD = 0.006 ``Weight of evidence'' approach
UFA = 10x........... mg/kg/day. from four studies. Rat subchronic
UFH = 10x........... and chronic studies with the
FQPA SF = UFL = 10x. LOAEL based on inhibition of
brain glutamate synthetase. A dog
chronic study with the LOAEL
based on altered
electrocardiogram and mortality.
The rat developmental
neurotoxicity study with a LOAEL
(without a NOAEL, basis for UFL)
based on altered morphometrics in
the offspring as adults.
Dermal short-term (1 to 30 days). LOAEL= 14 mg/kg/day LOC for MOE = 1,000 Developmental Neurotoxicity Study
(LDT). in Rats
UFA=10x............. LOAEL = 14 mg/kg/day based on
UFH=10x............. brain morphometric changes at PND
FQPA SF= UFL= 10x... 72. No NOAEL identified.
Cancer (Oral, dermal, inhalation) Classification: ``Not likely to be Carcinogenic to Humans'' based on the
absence of significant tumor increases in two adequate rodent
FQPA SF = Food Quality Protection Act Safety Factor. LOAEL = lowest-observed-adverse-effect-level. LOC = level
of concern. mg/kg/day = milligram/kilogram/day. MOE = margin of exposure. NOAEL = no-observed-adverse-effect-
level. PAD = population adjusted dose (a = acute, c = chronic). RfD = reference dose UF = uncertainty factor.
UFA = extrapolation from animal to human (interspecies). UFH = potential variation in sensitivity among
members of the human population (intraspecies). UFL = use of a LOAEL to extrapolate a NOAEL.
C. Exposure Assessment
1. Dietary exposure from food and feed uses. In evaluating dietary
exposure to glufosinate ammonium, EPA considered exposure under the
petitioned-for tolerances as well as all existing glufosinate ammonium
tolerances in 40 CFR 180.473. EPA assessed dietary exposures from
glufosinate ammonium 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.
Such effects were identified for glufosinate ammonium for females
13 through 50 years old. In estimating acute dietary exposure
assessment of glufosinate ammonium, EPA used the Dietary Exposure
Evaluation Model software with the Food Commodity Intake Database DEEM-
FCIDTM, Version 3.10, which incorporates consumption data
from USDA's National Health and Nutrition Examination Survey/``What We
Eat in America'' (NHANES/WWEIA) dietary survey conducted in 2003-2008.
The 2003-2008 data are based on the reported consumption of individuals
over two non-consecutive survey days.
As to residue levels in food, EPA assumed tolerance level residues
for all established and recommended tolerances along with default
processing factors, and 100 percent crop treated (PCT) assumptions.
ii. Chronic exposure. In conducting the chronic dietary exposure
assessment, EPA also used the Dietary Exposure Evaluation Model
software with the Food Commodity Intake Database DEEM-
FCIDTM, Version 3.10.
As to residue levels in food, EPA used anticipated residues based
on average residue levels from field trial studies. The DEEM default
processing factors were used for all commodities except apple juice,
pear juice, grape juice, and raisins, for which factors derived from
the processing studies were used in the assessment. One hundred percent
crop treated values were used for all proposed new uses and some
registered uses. Average PCT estimates were used in the chronic dietary
analysis for crops that are currently registered for glufosinate
ammonium if available.
iii. Cancer. Based on the data summarized in Unit III.A., EPA has
concluded that glufosinate ammonium does not pose a cancer risk to
humans. Therefore, a dietary exposure assessment for the purpose of
assessing cancer risk is unnecessary.
iv. Anticipated residue and percent crop treated (PCT) information.
Section 408(b)(2)(E) of 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 residues that have been
measured in food. If EPA relies on such information, EPA must require
pursuant to FFDCA section 408(f)(1) 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. For the present action, EPA will issue such data call-ins
as are required by FFDCA section 408(b)(2)(E) and authorized under
FFDCA section 408(f)(1). Data will be required to be submitted no later
than 5 years from the date of issuance of these tolerances.
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:
Condition a: 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 the pesticide residue.
Condition b: The exposure estimate does not underestimate
exposure for any significant subpopulation group.
Condition c: 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 FFDCA section 408(b)(2)(F), EPA may require
registrants to submit data on PCT.
The Agency estimated the average PCT for existing uses as follows:
Almond: 15%; blueberry: 5%; field corn, 5%; grape, 15%; pecan, 1%;
potato, 10%; soybean, 1%; walnut, 10%; canola, 25%; cotton, 5%;
filbert, 10%; pistachio, 20%; and rice, 1%.
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 Pesticide Use
Database for the chemical/crop combination for the most recent 6-7
years. EPA uses an average PCT for chronic dietary risk analysis. The
average PCT figure for each existing use is derived by combining
available public and private market survey data for that use, averaging
across all observations, and rounding to the nearest 5%, except for
those situations in which the average PCT is less than one. In those
cases, 1% is used as the average PCT and 2.5% is used as the maximum
PCT. EPA uses a maximum PCT for acute dietary risk analysis. The
maximum PCT figure is the highest observed maximum value reported
within the recent 6 years of available public and private market survey
for the existing use and rounded up to the nearest multiple of 5%.
The Agency believes that the three conditions discussed in Unit
III.C.1.iv. have been met. With respect to Condition a, 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 b and c, 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 reliable information on the regional consumption of
food to which glufosinate ammonium may be applied in a particular area.
2. Dietary exposure from drinking water. The Agency used refined
drinking water exposure models in the dietary exposure analysis and
risk assessment for glufosinate ammonium. These simulation models take
into account data on the physical, chemical, and fate/transport
characteristics of glufosinate ammonium. 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.
Environmental fate studies indicate glufosinate ammonium is
relatively stable and is very mobile. The main degradation pathway in
water and soil is via microbial action, metabolizing primarily to
CO2, glufosinate propanoic acid (MPP), 2-methylphosphinico
acetic acid (MPA), and 2-acetamido-4-methylphosphinico-butanoic acid
(NAG). EPA recently reconsidered the appropriate residues of concern
for drinking water to be used in risk assessment and determined that
only the parent, glufosinate ammonium is the residue of concern for
drinking water. Though MPA is a major degradate in some studies, a 90-
day rat feeding study showed no effects at the highest dose tested
which is about 100-fold higher than the NOAEL of the parent. Based on
the rabbit developmental studies NAG is considered slightly less toxic
than the parent. However, it was only observed as a major degradate
during photolysis in soil; therefore, its exposure is significantly
lower to that of the parent in drinking water. The parent glufosinate
ammonium and MPP show different toxicities and therefore should not be
aggregated. Moreover, the Agency has determined that the acute
concentrations of MPP are not likely to be significantly greater than
that of glufosinate in drinking water. However, given the minimal fate
data available for MPP that indicates MPP does not degrade in aerobic
aquatic environments, it is unclear if this will be true for chronic
concentrations of MPP and glufosinate. Since MPP is considered less
toxic than the parent compound and should not be aggregated with the
parent, EPA concluded that if estimated drinking water concentrations
(EDWCs) of MPP are not significantly greater than those for
glufosinate, the risk assessment for the parent will be protective of
any toxicity associated with exposure to MPP in drinking water.
Previous analyses for glufosinate ammonium demonstrated that the
maximum acute and chronic EDWCs result from surface water estimates
arising from the rice use; the surface water values for rice are nearly
an order of magnitude higher than any surface or ground water values
for any other use of glufosinate ammonium. Therefore, a comprehensive
refinement of the drinking water assessment for the rice use of
glufosinate ammonium, should be protective of other uses.
The Agency estimated acute EDWCs for glufosinate ammonium and MPP
using the Tier I Rice Model and Pesticide Flooded Application Model
(PFAM) [version 0.70] without the index reservoir. To estimate chronic
EDWCs, the acute concentrations from PFAM without the index reservoir
were assumed to degrade over a 365-day period, using aerobic aquatic
degradation half-lives; thus allowing calculation of average
concentrations over a one-year period. This method results in chronic
values approximately 76% and 3% lower than the acute values for
glufosinate-ammonium and MPP, respectively.
The EDWCs for surface water are expected to be 390 parts per
billion (ppb) for glufosinate and 183 ppb for MPP for acute exposures.
The EDWCs for surface water are expected to be 95 ppb for glufosinate
and 177 ppb for MPP for chronic exposures. The maximum chronic EDWC for
rice for MPP is approximately 2X higher than the corresponding value
for glufosinate: 177 and 95 ppb, respectively. Since MPP is considered
less toxic than the parent compound and should not be aggregated with
the parent, EPA concluded that if the EDWCs for MPP are not
significantly greater than those for glufosinate, the risk assessment
for the parent will be protective of any toxicity associated with
exposure to MPP in drinking water. Given the estimated EDWCs for MPP
concentrations are not likely to be more than twice the corresponding
levels of glufosinate in drinking water, EPA concluded a quantitative
risk assessment for MPP in drinking water is not needed. Accordingly,
for purposes of acute and chronic dietary analyses, the recommended
glufosinate EDWCs are 390 and 95 ppb, respectively.
Modeled estimates of drinking water concentrations were directly
entered into the dietary exposure model. For acute dietary risk
assessment, the water concentration value of 390 ppb was used to assess
the contribution to drinking water. For chronic dietary risk
assessment, the water concentration of value 95 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). Glufosinate ammonium
is currently registered for the following uses that could result in
residential exposures: spot treatments of lawns and turf. EPA assessed
residential exposure using the following assumptions:
Residential handler exposure is expected to be short-term.
Intermediate-term exposures are not likely because of the intermittent
nature of applications by homeowners. Dermal and inhalation exposures
are possible for applications from mixing/loading/applying liquids with
a hose-end sprayer, a backpack sprayer, and a sprinkler can and
applications for manually pressurized handgun. However, only the dermal
route of exposure was included in the aggregate analysis since
potential dermal risks are higher than potential inhalation risks and
the EPA determined it is not appropriate to aggregate the dermal and
inhalation exposures since the toxicity endpoints are different.
The Agency did not quantify post-application exposures. Post-
application exposure is expected to be minimal. Any exposure to
children via incidental non-dietary ingestion (i.e., hand-to-mouth,
object-to-mouth (turfgrass), and soil ingestion) after application to
treated turf is expected to be low since
treatments to lawns and turf are limited to spot treatments.
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.''
EPA has not found glufosinate ammonium to share a common mechanism
of toxicity with any other substances, and glufosinate ammonium does
not appear to produce a toxic metabolite produced by other substances.
For the purposes of this tolerance action, therefore, EPA has assumed
that glufosinate ammonium does not have 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 EPA's Web site
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 Safety
Factor (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
2. Prenatal and postnatal sensitivity. The reproductive toxicity
study in rats indicated postnatal developmental toxicity at the highest
dose tested in the form of decrease in viable pups. No parental
toxicity was seen at the highest dose tested. Since pup mortality was
observed in the absence of parental toxicity, there is evidence of
quantitative increased susceptibility in offspring. Although in the rat
developmental toxicity study dilated renal pelvis and hydroureter were
observed in fetuses at 250 mg/kg/day, significant toxicity in the dams
occurred at lower doses (vaginal bleeding and hyperactivity in the dams
at 50 mg/kg/day), doses at which no developmental effects were
observed. Therefore, no increased sensitivity was seen in this study.
Since increased fetal mortality was observed in the presence of
less significant maternal toxicity in the rabbit developmental study,
there is evidence of qualitative increased susceptibility in fetuses.
Finally, the developmental neurotoxicity study demonstrated alterations
in brain morphometrics in the adult offspring exposed in utero or
during lactation at dose levels not associated with maternal toxicity.
This shows quantitative sensitivity in the young.
3. Conclusion. EPA has determined that reliable data show the
safety of infants and children would be adequately protected if the
FQPA safety factor were reduced to 1X for acute dietary exposure. For
all other exposure scenarios where the developmental neurotoxicity
study or the 28-day inhalation study is used as an endpoint for risk
assessment, EPA is retaining a 10X FQPA safety factor. That decision is
based on the following findings:
i. Although all required studies for glufosinate ammonium have been
submitted, the glufosinate ammonium database has a completeness issue
in that the developmental neurotoxicity and the 28-day inhalation
studies used for risk assessment did not demonstrate NOAELs, and LOAELs
were used as endpoints. Therefore, the 10X FQPA safety factor was
retained for use of a LOAEL to extrapolate a NOAEL. EPA has reduced the
10X safety factor when relying on a LOAEL in circumstances that suggest
that the LOAEL is approaching a NOAEL (e.g., very minimal effects seen
at the LOAEL). EPA, however has no reliable data supporting selection
of a different safety factor value other than the default value of 10X
for glufosinate ammonium.
ii. Although there were indications of neurotoxicity in several
studies, the PODs and safety factors chosen for risk assessment are
protective for these effects. The developmental neurotoxicity study
showed altered brain morphometrics at the LOAEL, and this study is used
in the weight-of-the evidence decision-making process for selection of
an endpoint. Applying the 10X FQPA Safety Factor for the LOAEL to NOAEL
extrapolation, as well as the 10X inter- and intra-species uncertainty
factors, to this LOAEL will be protective against possible
neurotoxicity as indicated in the laboratory animal studies.
iii. Although there is evidence that glufosinate ammonium results
in increased qualitative or quantitative susceptibility in the
developmental neurotoxicity study (rats), a prenatal developmental
study (rabbits), and in the 2-generation reproduction study (rats), the
PODs selected for risk assessment are protective for these effects
because they are either based on clear NOAELs for the effects in young
animals or they are based on a LOAEL adjusted by a 10X safety factor to
account for the lack of a NOAEL in that study.
iv. There are no residual uncertainties identified in the exposure
databases. The acute dietary food exposure assessment was performed
based on 100 PCT and tolerance-level residues. The chronic dietary
exposure analysis was performed using anticipated residues from field
trial data, processing factors, and PCT information. With limited
monitoring data available, upper-bound assumptions were used to
determine exposure through drinking water sources. EPA made
conservative (protective) assumptions in the ground and surface water
modeling used to assess exposure to glufosinate ammonium in drinking
water. These assessments will not underestimate the exposure and risks
posed by glufosinate ammonium.
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
acute PAD (aPAD) and chronic PAD (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 glufosinate ammonium will occupy 39% of the aPAD for females 13-49
years old, the population group receiving the greatest exposure.
2. Chronic risk. Using the exposure assumptions described in this
unit for chronic exposure, EPA has concluded that chronic exposure to
glufosinate ammonium from food and water will utilize 98% of the cPAD
for all infants (<1 year 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 glufosinate ammonium is not expected.
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).
Glufosinate ammonium is currently registered for uses 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 glufosinate
Using the exposure assumptions described in this unit for short-
term exposures, EPA has concluded the combined short-term food, water,
and residential exposures result in aggregate MOEs of 1,800 for the
general population for mixer/loader/applicators. Because EPA's level of
concern for glufosinate ammonium is an MOE of 1,000 or below, these
MOEs 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
An intermediate-term adverse effect was identified; however,
glufosinate ammonium is not registered for any use patterns that would
result in intermediate-term residential exposure. Intermediate-term
risk is assessed based on intermediate-term residential exposure plus
chronic dietary exposure. Because there is no intermediate-term
residential exposure and chronic dietary exposure has already been
assessed under the appropriately protective cPAD (which is at least as
protective as the POD used to assess intermediate-term risk), no
further assessment of intermediate-term risk is necessary, and EPA
relies on the chronic dietary risk assessment for evaluating
intermediate-term risk for glufosinate ammonium.
5. Aggregate cancer risk for U.S. population. Based on the lack of
evidence of carcinogenicity in two adequate rodent carcinogenicity
studies, glufosinate ammonium is not expected to pose a cancer risk to
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 glufosinate ammonium residues.
IV. Other Considerations
A. Analytical Enforcement Methodology
Two analytical methods have been validated by EPA for enforcement
of the currently established tolerances: (1) Method HRAV-5A for the
determination of glufosinate ammonium and glufosinate propanoic acid
in/on apple, grape, almond, soybean seed, corn grain, and corn forage,
and (2) Method BK/01/99 for determination of glufosinate ammonium, N-
acetyl-glufosinate, and glufosinate propanoic acid in/on canola seed
and sugar beet root.
Based on the similarity in the two methods and the results from the
petition method validations (PMVs), EPA concludes that method BK/01/99
is a suitable method for enforcement of sweet corn, stone fruit, pome
fruit, citrus fruit, and olive tolerances.
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; email address:
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 United Nations
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 MRLs for glufosinate ammonium in or
on olives and sweet corn commodities. However, for glufosinate ammonium
in or on citrus fruit, pome fruit, and stone fruit, Codex has set MRLs
of 0.1, 0.05, and 0.05 ppm, respectively. EPA is establishing
tolerances in this action for citrus fruit, pome fruit, and stone
fruit, at 0.15, 0.25, and 0.25 ppm, respectively. EPA cannot harmonize
these tolerance values with the Codex MRLs because the lower MRLs could
be exceeded with the uses petitioned-for in this action.
C. Revisions to Petitioned-for Tolerances
EPA modified/revised certain IR-4 proposed tolerances for
glufosinate ammonium residues. Higher tolerance levels were established
for citrus, pome fruit, stone fruit, and olives because EPA concluded
that it was appropriate to sum the full level of quantification (LOQ)
for each of the three residues of concern in situations where < LOQ
residue levels were found. Sweet corn tolerances were amended based on
results from the Organization for Economic Co-operation and Development
(OECD) tolerance calculation procedures the corn, sweet, K+CWHR
tolerance proposed at 0.2 ppm will be established at 0.30 ppm, corn,
sweet, forage tolerance proposed at 4.0 ppm will be established at 1.5
ppm. A separate prune tolerance was established as residues in this
processed commodity are covered by the stone fruit group tolerance.
Additionally, EPA was petitioned for tolerances on citrus fruit
group 10, pome fruit group 11, and stone fruit group 12. In the Federal
Register of December 8, 2010 (75 FR 76284) (FRL-8853-8) and Wednesday,
August 22, 2012, EPA issued final rules that revised the crop grouping
regulations. As part of those actions, EPA expanded and revised the
existing citrus fruit group, pome fruit group, and stone fruit group.
The revised crop groups are designated as citrus fruit group 10-10,
pome fruit group 11-10, and stone fruit group 12-12. As noted in the
two crop group rulemakings, it is EPA policy to attempt to conform
petitions for crop group tolerances filed prior the finalization of
amendments to crop groups to the crop groups, as revised. This was
possible in this case because the representative commodities for the
crop groups did not change and the increased exposure as a result of
the expanded crop groups could be assessed as part of review of the
petition. Therefore, consistent with this policy, EPA has assessed and
is establishing a tolerance on citrus fruit group 10-10, pome fruit
group 11-10, and stone fruit group 12-12.
Finally, EPA has revised the tolerance expression to clarify (1)
that, as provided in FFDCA section 408(a)(3), the tolerance covers
metabolites and degradates of glufosinate ammonium not specifically
mentioned; and (2) that compliance with the specified tolerance levels
is to be determined by measuring only the specific compounds mentioned
in the tolerance expression.
Therefore, tolerances are established for residues of glufosinate
ammonium (butanoic acid, 2-amino-4-(hydroxymethylphosphinyl)
monoammonium salt) and its metabolites, 2-(acetylamino)-4-
(hydroxymethyl phosphinyl) butanoic acid, and 3-
(hydroxymethylphosphinyl) propanoic acid, expressed as 2-amino-4-
(hydroxymethylphosphinyl)butanoic acid equivalents in or on corn,
sweet, forage at 1.5 ppm; corn, sweet, kernels plus cob with husks
removed at 0.30 ppm; corn, sweet, stover at 6.0 ppm; fruit, citrus,
group 10-10 at 0.15 ppm; fruit, pome, group 11-10 at 0.25 ppm; fruit,
stone, group 12-12 at 0.25 ppm; and olive at 0.15 ppm.
VI. Statutory and Executive Order Reviews
This final rule establishes tolerances under FFDCA section 408(d)
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 FFDCA section 408(d), 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 FFDCA section 408(n)(4). 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) (2 U.S.C. 1501 et seq.).
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) (15 U.S.C. 272 note).
VII. Congressional Review Act
Pursuant to the Congressional Review Act (5 U.S.C. 801 et seq.),
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
the rule in the Federal Register. This action 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
Dated: September 19, 2012.
G. Jeffrey Herndon,
Acting Director, Registration Division, Office of Pesticides Programs.
Therefore, 40 CFR chapter I is amended as follows:
1. The authority citation for part 180 continues to read as follows:
Authority: 21 U.S.C. 321(q), 346a and 371.
2. Section 180.473 is amended as follows:
i. Revise the introductory text in paragraphs (a) and (d).
ii. Add alphabetically the following commodities to the table in
The revised and added text reads as follows:
Sec. 180.473 Glufosinate ammonium; tolerances for residues.
(a) General. Tolerances are established for residues of the
herbicide glufosinate ammonium, 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 the sum of glufosinate ammonium, butanoic acid, 2-amino-4-
(hydroxymethylphosphinyl) monoammonium salt, and its metabolites, 2-
(acetylamino)-4-(hydroxymethyl phosphinyl)butanoic acid, and 3-
(hydroxymethylphosphinyl)propanoic acid, expressed as 2-amino-4-
(hydroxymethylphosphinyl)butanoic acid equivalents:
* * * * *
Corn, sweet, forage....................................... 1.5
Corn, sweet, kernels plus cob with husks removed.......... 0.30
Corn, sweet, stover....................................... 6.0
* * * * *
Fruit, citrus, group 10-10................................ 0.15
Fruit, pome, group 11-10.................................. 0.25
Fruit, stone, group 12-12................................. 0.25
* * * * *
* * * * *
* * * * *
(d) Indirect or inadvertent residues. Tolerances are established
for indirect or inadvertent residues of glufosinate ammonium, including
its metabolites and degradates, in or on the commodities in the table
below, as a result of the application of glufosinate ammonium to crops
listed in paragraph (a) of this section. Compliance with the tolerance
levels specified below is to be determined by measuring the sum of
glufosinate ammonium, butanoic acid, 2-amino-4-
(hydroxymethylphosphinyl) monoammonium salt, and its metabolite, 3-
(hydroxymethylphosphinyl) propanoic acid, expressed as 2-amino-4-
(hydroxymethylphosphinyl)butanoic acid equivalents.
* * * * *
[FR Doc. 2012-23738 Filed 9-25-12; 8:45 am]
BILLING CODE 6560-50-P