Glyphosate - Pesticide Petition Filing 3/02
ENVIRONMENTAL PROTECTION AGENCY
Notice of Filing Pesticide Petitions to Establish a Tolerance for
Certain Pesticide Chemicals in or on Food
AGENCY: Environmental Protection Agency (EPA).
SUMMARY: This notice announces the initial filing of pesticide
petitions proposing the establishment of regulations for residues of
certain pesticide chemicals in or on various food commodities.
DATES: Comments, identified by docket control number PF-1079, must be
received on or before May 17, 2002.
ADDRESSES: Comments may be submitted by mail, electronically, or in
person. Please follow the detailed instructions for each method as
provided in Unit I.C. of the SUPPLEMENTARY INFORMATION. To ensure
proper receipt by EPA, it is imperative that you identify docket
control number PF-1079 in the subject line on the first page of your
FOR FURTHER INFORMATION CONTACT: James A. Tompkins, Registration
Division (7505C), Office of Pesticide Programs, Environmental
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460;
telephone number: (703) 305-5697; e-mail address:
I. General Information
A. Does this Action Apply to Me?
You may be affected by this action if you are an agricultural
producer, food manufacturer or pesticide manufacturer. Potentially
affected categories and entities may include, but are not limited to:
Categories NAICS codes potentially
Industry 111 Crop production
112 Animal production
311 Food manufacturing
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in the table could also be
affected. The North American Industrial Classification System (NAICS)
codes have been provided to assist you and others in determining
whether or not this action might apply to certain entities. If you have
questions regarding the applicability of this action to a particular
entity, consult the person listed under FOR FURTHER INFORMATION
B. How Can I Get Additional Information, Including Copies of this
Document and Other Related Documents?
1. Electronically. You may obtain electronic copies of this
document, and certain other related documents that might be available
electronically, from the EPA Internet Home Page at http://www.epa.gov/.
To access this document, on the Home Page select "Laws and
Regulations" "Regulations andProposed Rules" and then look up the
entry for this document under the "Federal Register--Environmental
Documents." You can also go directly to the Federal Register listings
2. In person. The Agency has established an official record for
this action under docket control number PF-1079. The official record
consists of the documents specifically referenced in this action, any
public comments received during an applicable comment period, and other
information related to this action, including any information claimed
as confidential business information (CBI). This official record
includes the documents that are physically located in the docket, as
well as the documents that are referenced in those documents. The
public version of the official record does not include any information
claimed as CBI. The public version of the official record, which
includes printed, paper versions of any electronic comments submitted
during an applicable comment period, is available for inspection in the
Public Information and Records Integrity Branch (PIRIB), Rm. 119,
Crystal Mall #2, 1921 Jefferson Davis Highway, Arlington, VA, from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
C. How and to Whom Do I Submit Comments?
You may submit comments through the mail, in person, or
electronically. To ensure proper receipt by EPA, it is imperative that
you identify docket control number PF-1079 in the subject line on the
first page of your response.
1. By mail. Submit your comments to: Public Information and Records
Integrity Branch (PIRIB), Information Resources and Services Division
(7502C), Office of Pesticide Programs (OPP), Environmental Protection
Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
2. In person or by courier. Deliver your comments to: Public
Information and Records Integrity Branch (PIRIB), Information Resources
and Services Division (7502C), Office of Pesticide Programs (OPP),
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921
Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
3. Electronically. You may submit your comments electronically by
e-mail to: firstname.lastname@example.org, or you can submit a computer disk as
described above. Do not submit any information electronically that you
consider to be CBI. Avoid the use of special characters and any form of
encryption. Electronic submissions will be accepted in Wordperfect 6.1/
8.0 or ASCII file format. All comments in electronic form must be
identified by docket control number PF-1079. Electronic comments
may also be filed online at many Federal Depository Libraries.
D. How Should I Handle CBI That I Want to Submit to the Agency?
Do not submit any information electronically that you consider to
be CBI. You may claim information that you submit to EPA in response to
this document as CBI by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
with procedures set forth in 40 CFR part 2. In addition to one complete
version of the comment that includes any information claimed as CBI, a
copy of the comment that does not contain the information claimed as
CBI must be submitted for inclusion in the public version of the
official record. Information not marked confidential will be included
in the public version of the official record without prior notice. If
you have any questions about CBI or the procedures for claiming CBI,
please consult the person listed under FOR FURTHER INFORMATION CONTACT.
E. What Should I Consider as I Prepare My Comments for EPA?
You may find the following suggestions helpful for preparing your
1. Explain your views as clearly as possible.
2. Describe any assumptions that you used.
3. Provide copies of any technical information and/or data you used
that support your views.
4. If you estimate potential burden or costs, explain how you
arrived at the estimate that you provide.
5. Provide specific examples to illustrate your concerns.
6. Make sure to submit your comments by the deadline in this
7. To ensure proper receipt by EPA, be sure to identify the docket
control number assigned to this action in the subject line on the first
page of your response. You may also provide the name, date, and Federal
II. What Action is the Agency Taking?
EPA has received pesticide petitions as follows proposing the
establishment and/or amendment of regulations for residues of certain
pesticide chemicals in or on various food commodities under section 408
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a.
EPA has determined that these petitions contain data or information
regarding the elements set forth in section 408(d)(2); however, EPA has
not fully evaluated the sufficiency of the submitted data at this time
or whether the data support granting of the petition. Additional data
may be needed before EPA rules on the petition.
List of Subjects
Environmental protection, Agricultural commodities, Feed additives,
Food additives, Pesticides and pests, Reporting and recordkeeping
Dated: March 28, 2002.
Acting Director, Registration Division, Office of Pesticide Programs.
Summaries of Petitions
The Petitioner's summaries of the pesticide petitions are printed
below as required by section 408(d)(3) of the FFDCA. The summaries of
the petitions were prepared by the petitioner and represent the views
of the petitioner. EPA is publishing the petition summaries verbatim
without editing them in any way. The petition summary announces the
availability of a description of the analytical methods available to
EPA for the detection and measurement of the pesticide chemical
residues or an explanation of why no such method is needed.
PP 0F6130, PP 0F6195, PP 1F6273, PP 1F6274, PP1F6295
EPA has received several pesticide petitions (PP 0F6130, PP 0F6195,
PP 1F6273, PP 1F6274, PP 1F6295) from Monsanto Company, 600 13th
Street, NW., Washington, DC 20005 proposing, pursuant to section 408(d)
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d),
to amend 40 CFR part 180 by establishing several tolerances for
residues of glyphosate (N-(phosphonomethyl) glycine). In the Federal
Register of July 25, 2000 (65 FR 45769) (FRL-6596-4), EPA issued a
notice pursuant to section 408 of the FFDCA announcing the filing of a
pesticide petition (PP 0F6130) for tolerance by Monsanto Company; that
petition has been amended and is accordingly re-notified. Monsanto
requests that 40 CFR 180.364 be amended by establishing tolerances for
residues of glyphosate (N-(phosphonomethyl) glycine) per se resulting
from the application of glyphosate, the isopropylamine salt of
glyphosate, the ethanolamine salt of glyphosate, the potassium salt of
glyphosate, and/or the ammonium salt of glyphosate in or on the listed
raw agricultural commodities, (RACs) to include: grass, forage, fodder,
and hay group at 300 parts per million (ppm); aspirated grain fractions
at 100 ppm; corn, field, forage at 6.0 ppm; wheat, forage at 10.0 ppm;
wheat, hay at 10.0 ppm; animal feeds, nongrass group at 400 ppm; rice,
grain at 15.0 ppm; rice, bran at 30.0 ppm; and rice, hulls at 25.0 ppm
and to increase the established tolerance for wheat, grain to 6.0 ppm.
In addition, PP 1F6274 requests to revise the present tolerance for
cereal grains group to be "grain, cereal group (except barley, field
corn, grain sorghum, oats, rice, and wheat)." Finally, Monsanto seeks
to delete the existing tolerance for soybean, aspirated grain fractions
at 50.0 ppm since this tolerance will be included in the "aspirated
grain fractions" described above, and PP 1F6273 seeks to delete the
existing tolerance for animal, feeds, nongrass group (except alfalfa),
which will be included in the above proposed "animal feeds, nongrass
group" tolerance. The tolerances proposed for rice and wheat
commodities, and the grass, forage, fodder, and hay group include both
conventional and glyphosate tolerant rice, wheat, and creeping
bentgrass. EPA has determined that the petitions contains data or
information regarding the elements set forth in section 408(d)(2) of
the FFDCA; however, EPA has not fully evaluated the sufficiency of the
submitted data at this time or whether the data supports granting of
the petitions. Additional data may be needed before EPA rules on the
A. Residue Chemistry
1. Plant metabolism. The nature of the residue in plants is
adequately understood and consists of the parent, glyphosate and its
metabolite aminomethyl-phosphonic acid (AMPA). Only glyphosate parent
is to be regulated in plant and animal commodities since the metabolite
AMPA is not of toxicological concern in food. The qualitative nature of
the glyphosate residue will not be changed as a result of the proposed
The qualitative nature of the residue in animals is adequately
understood, and will not be affected by the proposed tolerance change.
Glyphosate herbicides are not applied directly to livestock, so their
only exposure is via plant residues in their diet. The terminal residue
to be regulated in livestock is glyphosate per se.
2. Analytical method. Adequate enforcement methods are available
for analysis of residues of glyphosate in or on plant commodities.
These methods include gas liquid chromatography
(GLC) (Method I in Pesticides Analytical Manual (PAM) II; the limit of
detection is 0.05 ppm) and high performance liquid chromatography
(HPLC) with fluorometric detection. The HPLC procedure has undergone
successful Agency validation and was recommended for inclusion in PAM
II. A gas chromatography/mass spectrometry (GC/MS) method for
glyphosate crops has also been validated by EPA's Analytical Chemistry
Laboratory (ACL). The proposed revisions in the tolerance regulation do
not change the residue to be analyzed, which remains as glyphosate per
3. Magnitude of residues. Adequate data concerning glyphosate
residues on raw agricultural commodities (RACs) and relevant processed
commodities has been submitted to the Agency. Accordingly, the
available residue data for glyphosate support the proposed revisions of
the tolerance regulation for glyphosate. In addition, any secondary
residues occurring in liver, or kidney of cattle, goats, horses, sheep,
and meat-by-products of poultry, and eggs, will be covered by existing
tolerances. Existing glyphosate tolerances for fish and shellfish will
cover any residues occurring in harvestable aquatic species.
B. Toxicological Profile
1. Acute toxicity. Several acute toxicology studies place
technical-grade glyphosate in toxicity category III and toxicity IV.
Technical glyphosate is not a dermal sensitizer.
2. Genotoxicty. In an in viro rec-assay with B. subtilis H17 (rec+)
and M45 (rec-) and reverse mutation assay using E. coli WP2 hcr and S.
typhimurium strains, there was no evidence of gene toxicity
genotoxicity up to the limit dose or cytotoxicity in the presence or
absence of metabolic activation.
In an in vitro reverse gene mutation assay in S. typhimurium
bacteria, there was no evidence of induced mutant colonies over
background in Salmonella strains TA 98, TA 100, TA 1535, and TA 1537
both in the presence and absence of metabolic activation at doses up to
cytotoxic levels or the limit dose. In an in vitro gene mutation assay
in chinese hamster ovary (CHO) cells/hypoxanthine guanine phophoribosyl
transferase (HGPRT), there was no evidence of genotoxicity up to
cytotoxic levels in the presence or absence of metabolic activation. In
a bone marrow chromosome aberrations assay, there was no significant
increase in the frequency of chromosome aberrations in bone marrow at
the limit dose of 1,000 milligrams/kilograms (mg/kg) in both sexes of
3. Reproductive and developmental toxicity. In a prenatal
developmental toxicity in rats, the maternal no observe adverse effect
level (NOAEL) = 1,000 mg/kg/day based on mortality with a maternal
lowest observe adverse effect level (LOAEL) 3,500 mg/kg/day based on
mortality, increased clinical signs, and reduced body weight gain. The
developmental NOAEL = 1,000 mg/kg/day and the developmental LOAEL =
3,500 mg/kg/day based on decreases in total implantations/dam and
nonviable fetuses/dam, increased number of litters and fetuses with
unossified sternebrae, and decreased fetal body weight.
In a prenatal developmental toxicity in rabbits the maternal NOAEL
= 175 mg/kg/day, the maternal LOAEL = 350 mg/kg/day based on mortality,
and clinical signs. The developmental NOAEL = 175 mg/kg/day and the
developmental LOAEL = 350 mg/kg/day (insufficient litters available to
In a reproduction and fertility study with rats the parental/
systemic NOAEL = 500 mg/kg/day for males and females, the parental/
systemic LOAEL = 1,500 mg/kg/day for males and females based on
clinical signs, decreased body weights, decreased weight gain, and
decreased food consumption in both sexes. The reproductive/offspring
NOAEL = 500 kg/day for males and females and the reproductive/offspring
LOAEL = 1,500 mg/kg/day for males and females based on reduced pup
weights in both sexes during second and third weeks of lactation.
4. Subchronic toxicity. In a 90-day oral toxicity study in rats the
NOAEL is less than 50 mg/kg/day for both sexes and the LOAEL = 50 mg/
kg/day based on increased phosphorus and potassium in both sexes. In a
90-day oral toxicity study in mice the NOAEL = 1,500 mg/kg/day in both
sexes and the LOAEL = 7,500 mg/kg/day in both sexes based on decreased
body weight gain in both sexes. In a 21/28-day dermal toxicity study in
rabbits, the NOAEL = 1,000 mg/kg/day for males and 5,000 mg/kg/day for
females. The LOAEL = 5,000 mg/kg/day in males based on decreased food
5. Chronic toxicity. In a chronic toxicity study in dogs the NOAEL
= 500 mg/kg/day highest dose tested (HDT). The LOAEL was greater than
500 mg/kg/day. In a combined chronic toxicity/carcinogenicity study in
rats the NOAEL = 362 mg/kg/day in males and 457 mg/kg/day in females,
the LOAEL = 940 mg/kg/day in males and 1,183 kg/kg/day in females based
on decreased weight gain in females, and increased incidence of
cataracts and lens abnormalities, decreased urinary pH, increased
absolute liver weight, and increased relative liver weight/brain weight
in males. There was no evidence of carcinogenicity. In a
carcinogenicity study in mice the NOAEL = 750 mg/kg/day in males and
females, the LOAEL = 4,500 mg/kg/day in both sexes based on decreased
body weight gains in both sexes, increased incidence of renal proximal
tubule epithelial basophilia and hypertrophy in females and increased
incidence of interstitial nephritis, hepatocellular hypertrophy and
hepatocellular necrosis in males. There was no evidence of
6. Animal metabolism. The qualitative nature of the residue in
animal is adequately understood. Studies with lactating goats and
laying hens fed a mixture of glyphosate and AMPA indicate that the
primary route of elimination was by excretion (urine and feces). These
results are consistent with metabolism studies in rats, rabbits, and
cows. The terminal residues in eggs, milk, and animal tissues are
glyphosate and its metabolite AMPA; there was no evidence for further
metabolism. The terminal residue to be regulated in livestock is
glyphosate per se.
7. Metabolite toxicology. The metabolite AMPA has been determined
to not be of toxicological significance.
8. Endocrine disruption. The toxicology studies discussed above
measure numerous endpoints with sufficient sensitivity to detect
potential endocrine-modulating activity. No effects have been
identified in subchronic, chronic or developmental toxicity or multi-
generation reproduction studies to indicate any endocrine-modulating
activity by glyphosate. In addition, no adverse was seen when
glyphosate was tested in a dominant-lethal mutation assay. While this
assay was designed as a genetic toxicity test, agents that can affect
male reproduction function will also cause effects in this assay.
C. Aggregate Exposure
1. Dietary exposure. Tolerances have been established (40 CFR
180.364) for the residues of (N-(phosphonomethyl)glycine resulting from
the application of the isopropylamine salt of glyphosate, the ammonium
salt of glyphosate, and/or the ethanolamine salt of glyphosate, in or
on a variety of food and feed commodities. The petitioner proposes to
add potassium salt to this list of acceptable salt forms to which the
tolerances apply, and to amend or add a number of new animal feed
tolerances and one food tolerance. Tolerances are established for
cattle, goat, hog, horse,
and sheep kidney at 4.0 ppm, and liver at 0.5 ppm, and for poultry meat
at 0.1 ppm, eggs at 0.05 ppm, and poultry meat byproducts at 1.0 ppm,
based on animal-feeding studies and reasonable worst-case livestock
diets. This analysis showed that the existing livestock tolerances are
sufficient for any additional dietary burden arising from the proposed
Risk assessments were conducted by EPA to assess dietary exposure
from glyphosate in food as follows:
2. Acute exposure--Food. Acute dietary risk assessments are
performed for a food-use pesticide if a toxicological study has
indicated the possibility of an effect of concern occurring as a result
of a 1-day or single exposure. An acute dietary endpoint and dose was
not identified for glyphosate. A review of the rat and rabbit
developmental studies did not provide a dose or endpoint that could be
used for acute dietary risk purposes. Additionally, there are no data
requirements for acute and subchronic rat neurotoxicity studies since
there was no evidence of neurotoxicity in any of the toxicology studies
at very high doses and glyphosate lacks a leaving group.
3. Chronic exposure. i. In conducting this chronic dietary risk
assessment the dietary exposure evaluation model (DEEM)
analysis evaluated the individual food consumption as reported by
respondents in the United States Department of Agriculture (USDA) 1989-
1992 nationwide continuing surveys of food intake by individuals
(CSFII) and accumulated exposure to the chemical for each commodity.
The following assumptions were made for the chronic exposure
assessments: The chronic dietary exposure analysis was conducted using
the reference dose (RfD) of 2.0 mg/kg/day. The RfD is based on the
maternal NOAEL of 175 mg/kg/day from a developmental study and an
uncertainty factor (UF) of 100 (applicable to all population
subgroups). The DEEM analysis assumed tolerance level residues and 100%
of the crop treated in/on all commodities with an existing or proposed
glyphosate tolerance. These assumptions resulted in the following
theoretical maximum residue contributions (TMRC) and percentage RfDs
for certain population subgroups. The TMRC for the U.S. population (48
contiguous states) was 0.033727 mg/kg/day or 1.7% of the RfD, 0.029752
mg/kg/day or 1.5% of the RfD for nursing infants (less than 1-year
old), 0.094859 mg/kg/day or 4.7% of the RfD for non-nursing infants
less that 1-year old; 0.072062 mg/kg/day or 3.6% of the RfD of children
(1 to 6 years old); 0.047815 mg/kg/day or 2.4% of the RfD for children
(7 to 12 years old); 0.034216 mg/kg/day or 1.7% of the RfD for females
(13+/nursing); 0.033234 mg/kg/day or 1.7% of the RfD for non-hispanic
whites; 0.034578 mg/kg/day or 1.7% of the RfD for hispanics, and
0.035141 mg/kg/day or 1.7% of the RfD for non-hispanic blacks.
ii. Cancer. There is no evidence of carcinogenic potential.
4. Drinking water. The available field and laboratory data indicate
that glyphosate adsorbs strongly to soil and would not be expected to
move vertically below the 6 inch soil layer. Based on non-aged batch
equilibrium studies glyphosate and glyphosate residues are expected to
be immobile with Kd(ads) values ranging from 62 to 175. The mechanism
of adsorption is unclear; however, it is speculated that it may be
associated with vacant phosphate sorption sites or high levels of
metallic soil cations. The data indicate that chemical and photo-
chemical decomposition is not a significant pathway of degradation of
glyphosate in soil and water. However, glyphosate is readily degraded
by soil microbes to AMPA, which is degraded to CO2, although
at a slower rate than parent glyphosate. The proposed amendment to
permit the use of potassium glyphosate formulations is not expected to
change the environmental properties of glyphosate.
The Agency lacks sufficient monitoring exposure data to complete a
comprehensive dietary exposure analysis and risk assessment for
glyphosate in drinking water. Because the Agency does not have
comprehensive monitoring data, drinking water concentration estimates
are made by reliance on simulation or modeling taking into account data
on the physical characteristics of glyphosate.
The Agency uses the generic expected environmental concentration
(GENEEC) or the pesticide root zone/exposure analysis modeling system
(PRZM/EXAMS) to estimate pesticide concentrations in surface water and
the screening concentration and ground water (SCI-GROW) model, which
predicts pesticide concentrations in ground water. In general, EPA will
use GENEEC (a Tier 1 model) before using PRZM/EXAMS (a Tier 2 model)
for a screening-level assessment for surface water. The GENEEC model is
a subset of the PRZM/EXAMS model that uses a specific high-end runoff
scenario for pesticides. GENEEC incorporates a farm pond scenario,
while PRZM/EXAMS incorporate an index reservoir environment in place of
the previous pond scenario. The PRZM/EXAMS model includes a percent
crop area factor as a possible adjustment to account for the maximum
percent crop coverage within a watershed or drainage basin.
None of these models include consideration of the impact processing
(mixing, dilution or treatment) of raw water for distribution as
drinking water would likely have on the removal of pesticides from the
source water. The primary use of these models by the Agency at this
stage is to provide a coarse screen for sorting out pesticides for
which it is highly unlikely that drinking water concentrations would
ever exceed human health levels of concern.
Since the models used are considered to be screening tools in the
risk assessment process, the Agency does not use estimated
environmental concentrations (EECs) from these models to quantify
drinking water exposure and risk as a %RfD or percent of population
adjusted dose (%PAD). Instead, drinking water levels of comparison
(DWLOCs) are calculated and used as a point of comparison against the
model estimates of a pesticide's concentration in water. DWLOCs are
theoretical upper limits on a pesticide's concentration in drinking
water in light of total aggregate exposure to a pesticide in food, and
from residential uses. Since DWLOCs address total aggregate exposure to
glyphosate they are further discussed in the aggregate risk sections
Using available environmental fate parameters and assuming two
applications with a retreatment interval of 90 days at a rate of 5 lbs.
active ingredient/arce (3.75 lbs active ingredient/acre), the ground
water EEC from glyphosate using SCI-GROW was 0.0038 parts per billion
(ppb). The current label allows multiple applications of 0.37 - 5 lbs
active ingredient/acre up to a maximum of 10.6 lbs active ingredient/
acre/year. The ground water EECs generated by SCI-GROW are based on the
largest 90-day average recorded during the sampling period. Since there
is relatively little temporal variation in ground water concentrations
compared to surface water, the concentrations can be considered as
acute and chronic values.
The GENEEC model was used to estimate surface water concentrations
for glyphosate resulting from its maximum use rate on crops. GENEEC is
a single event model (one runoff event), but can account for spray
drift from multiple applications. GENEEC represents a 10 hectare field
immediately adjacent to a 1 hectare
pond that is 2 meters deep with no outlet. The pond receives a spray
drift event from each application plus one runoff event. The runoff
event moves a maximum of 10% of the applied pesticide into the pond.
This amount can be reduced due to degradation on the field and by soil
sorption. Spray drift is estimated as 5% of the application rate. The
GENEEC values represent upper-bound estimates of the concentrations
that might be found in the surface water due to glyphosate use. Thus,
the GENEEC model predicts that glyphosate surface water EECs range from
a peak of 21 ppb to a 56-day average of 2.5 ppb. For comparison
purposes, EPA guidance suggests dividing the 56-day GENEEC EEC value by
3 before comparison to the calculated DWLOC chronic value ("Interim
Guidance for Incorporating Drinking Water Exposure into Aggregate Risk
Assessments," August 1, 1999, SOP 99.5). Thus, 2.5 divided by 3 or
0.83 ppb is the predicted surface water EEC value resulting from
glyphosate treatment of crops.
To estimate the possible concentration of glyphosate in surface
water resulting form direct application to water, EPA assumed
application to a water body 6 feet deep. At an application rate of 3.75
lbs active ingredient/acre, the estimated peak concentration is 230
ppb. Using this peak value in a first-order dissipation model with a
half-life for glyphosate in water of 7.5 days, the resulting 56-day
average is 54.6 ppb. Following the EPA guidance, as described above,
the 56-day average value divided by 3, or 15.4 ppb, is the predicted
surface water EEC resulting from direct application to water. Because
the glyphosate water-application estimate is greater than the crop-
application estimate, 15.4 ppb is the appropriate chronic value to
compare to the calculated DWLOC chronic value for aggregate risk
Based on the GENEEC and SCI-GROW models the EECs of glyphosate for
chronic exposures are estimated to be 15.4 ppb for surface water and
0.004 ppb for ground water.
5. 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). Glyphosate is
currently registered for use on the following residential non-dietary
i. Ornamentals, greenhouses, residential areas, lawns, and
industrial rights of way.
ii. Glyphosate is formulated in liquid and solid forms and it is
applied using ground or aerial equipment.
iii. Based on the low acute toxicity and the lack of other
toxicological concerns, exposures from residential uses of glyphosate
are not expected to pose undue risks.
D. Cumulative Effects
Cumulative exposure to substances with a common mechanism of
toxicity. Section 408(b)(2)(D)(v) requires that, when considering
whether to establish, modify, or revoke a tolerance, the Agency
consider "available information" concerning the cumulative effects of
a particular pesticide's residue and "other substances that have a
common mechanism of toxicity."
EPA does not have, at this time, available data to determine
whether glyphosate has a common mechanism of toxicity with other
substances or how to include this pesticide in a cumulative risk
assessment. Unlike other pesticides for which EPA has followed a
cumulative risk approach based on a common mechanism of toxicity,
glyphosate does not appear to produce a toxic metabolite produced by
other substances. For the purposes of this tolerance action, therefore,
EPA has not assumed that glyphosate has a common mechanism of toxicity
with other substances. For information regarding EPA's efforts to
determine which chemicals have a common mechanism of toxicity and to
evaluate the cumulative effects of such chemicals, see the final rule
for bifenthrin pesticide tolerances (62 FR 62961)(FRL-5754-7), Federal
Register of November 26, 1997).
E. Safety Determination
1. U.S. population. To estimate total aggregate exposure to a
pesticide from food, drinking water, and residential uses, the Agency
calculates DWLOCs that are used as a point of comparison against the
model estimates of a pesticide's concentration in water. DWLOC values
are not regulatory standards for drinking water. DWLOCs are theoretical
upper limits on a pesticide's concentration in drinking water in light
of total aggregate exposure to a pesticide in food and residential
uses. In calculating a DWLOC, the Agency determines how much of the
acceptable exposure (i.e., the population adjusted dose (PAD)) is
available for exposure through drinking water, e.g., allowable chronic
water exposure (mg/kg/day) = chronic population adjusted dose (cPAD) -
(average food + residential exposure). This allowable exposure through
drinking water is used to calculate a DWLOC.
A DWLOC will vary depending on the toxic endpoint, drinking water
consumption, and body weights. Default body weights and consumption
values as used by EPA's Office of Water are used to calculate DWLOCs:
2L/70 kg (adult male), 2L/60 kg (adult female), and 1L/10 kg (child).
Default body weights and drinking water consumption values vary on an
individual basis. This variation will be taken into account in more
refined screening-level and quantitative drinking water exposure
assessments. Different populations will have different DWLOCs.
Generally, a DWLOC is calculated for each type of risk assessment used:
acute, short-term, intermediate-term, chronic, and cancer.
When EECs for surface water and ground water are less than the
calculated DWLOCs, the Office of Pesticide Programs (OPP) concludes
with reasonable certainty that exposures to the pesticide in drinking
water (when considered along with other sources of exposure for which
OPP has reliable data) would not result in unacceptable levels of
aggregate human health risk at this time. Because OPP considers the
aggregate risk resulting from multiple exposure pathways associated
with a pesticide's uses, levels of comparison in drinking water may
vary as those uses change. If new uses are added in the future, OPP
will reassess the potential impacts of residues of the pesticide in
drinking water as a part of the aggregate risk assessment process.
i. Acute risk. No appropriate toxicological endpoint for a single
dose exposure was identified in oral toxicity studies with glyphosate.
Therefore, an acute RfD was not established, and there is no
expectation of acute dietary risk from food and water.
ii. Chronic risk. Using the exposure assumptions described in this
unit for chronic exposure, EPA has concluded that exposure to
glyphosate from food using present tolerances and all proposed new
tolerances, will utilize 1.7% of the cPAD for the U.S. population, 3.8%
of the cPAD for all infants less than 1-year old and 3.6% of the cPAD
for children (1 to 6 years old). These dietary exposure levels take
into account all existing and proposed tolerances for glyphosate. Based
on the use pattern, chronic residential exposure to residues of
glyphosate is not expected. In addition, there is potential for chronic
dietary exposure to glyphosate in drinking water. After calculating
DWLOCs and comparing them to the EECs for surface and ground water, EPA
does not expect the aggregate exposure to exceed 100% of the cPAD.
DWLOCs for the U.S.
population, infants less than 1-year old, and children (1 to 6) are
69,000 ppb, 19,000 ppb, and 19,000 ppb, respectively, compared with
EECs of 0.004 ppb and 15.4 ppb for ground and surface water,
2. Infants and children. In general, FFDCA Section 408 provides
that EPA shall apply an additional ten-fold margin of safety (MOS) for
infants and children in the case of threshold effects to account for
prenatal and postnatal toxicity and the completeness of the data base
on toxicity and exposure unless EPA determines that a different MOS
will be safe for infants and children. Margins of safety are
incorporated into EPA risk assessments either directly through use of a
margin of exposure (MOE) analysis or through using uncertainty (safety)
factors in calculating a dose level that poses no appreciable risk to
humans. EPA believes that reliable data support using the standard UF
(usually 100 x for combined interspecies and intraspecies variability)
and not the additional ten-fold MOE/UF when EPA has a complete data
base under existing guidelines and when the severity of the effects in
infants or children or the potency or unusual toxic properties of a
compound do not raise concerns regarding the adequacy of the standard
i. Prenatal and postnatal sensitivity. There is no evidence of
increased susceptibility in rats and rabbits to in utero and/or
postnatal exposure to glyphosate.
ii. Conclusion. There is a complete toxicity data base for
glyphosate and exposure data are complete or are estimated based on
data that reasonably accounts for potential exposures. EPA determined
that the 10X SF to protect infants and children should be removed. The
FQPA factor is removed because:
The toxicology data base is complete.
There is no indication of increased susceptibility of rats
or rabbits to in utero and/or postnatal exposure to glyphosate (in the
prenatal developmental toxicity study in rats, effects in the offspring
were observed only at or above treatment levels which resulted in
evidence of appreciable parental toxicity).
The use of generally high quality data, conservative
models and/or assumptions in the exposure assessment provide adequate
protection of infants and children.
F. International Tolerances
Several maximum residue limits (MRLs) for glyphosate have been
established by CODEX in or on various commodities. These limits are
based on the residue definition of glyphosate per se, without reference
to the cation used in product formulations. Based on toxicological
considerations, EPA has determined that AMPA no longer needs to be
regulated and has deleted AMPA from the U.S. tolerance expression, so
that the U.S. residue definition is harmonized with that of CODEX. The
proposed rice grain tolerance of 15.0 ppm, is based on crop field trial
data obtained using glyphosate-tolerant rice and therefore cannot be
lowered to maintain harmonization with the CODEX MRL of 0.1 ppm, for
residues of glyphosate in or on this commodity. A CODEX MRL exists for
"hay or fodder (dry) of grasses" at 50.0 ppm, and on "maize forage"
at 1.0 ppm, however the proposed U.S. tolerance for "grass, forage,
fodder, and hay group" at 300 ppm, and "corn, field, forage" at 6.0
ppm, are based on higher application rates than those used in the
residue studies considered by CODEX, so that harmonization cannot be
maintained in these cases. Other than for these specific commodities,
the agreement between U.S. tolerances and Codex international residue
standards is unaffected by this action.
[FR Doc. 02-9324 Filed 4-16-02; 8:45 am]
BILLING CODE 6560-50-S