[Federal Register Volume 68, Number 131 (Wednesday, July 9, 2003)]
[Notices]
[Pages 40939-40944]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-17104]
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ENVIRONMENTAL PROTECTION AGENCY
[OPP-2003-0204; FRL-7314-1]
Zinc Phosphide; Notice of Filing a Pesticide Petition to
Establish a Tolerance for a Certain Pesticide Chemical in or on Food
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
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SUMMARY: This notice announces the initial filing of a pesticide
petition proposing the establishment of regulations for residues of a
certain pesticide chemical in or on various food commodities.
DATES: Comments, identified by docket ID number OPP-2003-0204, must be
received on or before August 8, 2003.
ADDRESSES: Comments may be submitted electronically, by mail, or
through hand delivery/courier. Follow the detailed instructions as
provided in Unit I. of the SUPPLEMENTARY INFORMATION.
FOR FURTHER INFORMATION CONTACT: Sidney Jackson, Registration Division
(7505C), Office of Pesticide Programs, Environmental Protection Agency,
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone
number: (703) 305-7610; e-mail address: [email protected].
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.
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. Potentially affected entities
may include, but are not limited to:
[sbull] Crop production (NAICS 111)
[sbull] Animal production (NAICS 112)
[sbull] Food manufacturing (NAICS 311)
[sbull] Pesticide manufacturing (NAICS 32532)
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in this unit could also be
affected. 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 Copies of this Document and Other Related Information?
1. Docket. EPA has established an official public docket for this
action under docket identification (ID) number OPP-2003-0204. The
official public docket consists of the documents specifically
referenced in this action, any public comments received, and other
information related to this action. Although a part of the official
docket, the public docket does not include Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute. The official public docket is the collection of materials
that is available for public viewing at the Public Information and
Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall 2,
1921 Jefferson Davis Hwy., Arlington, VA. This docket facility is open
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal
holidays. The docket telephone number is (703) 305-5805.
2. Electronic access. You may access this Federal Register document
electronically through the EPA Internet under the ``Federal Register''
listings at http://www.epa.gov/fedrgstr/.
An electronic version of the public docket is available through
EPA's electronic public docket and comment system, EPA Dockets. You may
use EPA Dockets at http://www.epa.gov/edocket/ to submit or view public
comments, access the index listing of the contents of the official
public docket, and to access those documents in the public docket that
are available electronically.
[[Page 40940]]
Although not all docket materials may be available electronically, you
may still access any of the publicly available docket materials through
the docket facility identified in Unit I.B.1. Once in the system,
select ``search,'' then key in the appropriate docket ID number.
Certain types of information will not be placed in the EPA Dockets.
Information claimed as CBI and other information whose disclosure is
restricted by statute, which is not included in the official public
docket, will not be available for public viewing in EPA's electronic
public docket. EPA's policy is that copyrighted material will not be
placed in EPA's electronic public docket but will be available only in
printed, paper form in the official public docket. To the extent
feasible, publicly available docket materials will be made available in
EPA's electronic public docket. When a document is selected from the
index list in EPA Dockets, the system will identify whether the
document is available for viewing in EPA's electronic public docket.
Although not all docket materials may be available electronically, you
may still access any of the publicly available docket materials through
the docket facility identified in Unit I.B. EPA intends to work towards
providing electronic access to all of the publicly available docket
materials through EPA's electronic public docket.
For public commenters, it is important to note that EPA's policy is
that public comments, whether submitted electronically or in paper,
will be made available for public viewing in EPA's electronic public
docket as EPA receives them and without change, unless the comment
contains copyrighted material, CBI, or other information whose
disclosure is restricted by statute. When EPA identifies a comment
containing copyrighted material, EPA will provide a reference to that
material in the version of the comment that is placed in EPA's
electronic public docket. The entire printed comment, including the
copyrighted material, will be available in the public docket.
Public comments submitted on computer disks that are mailed or
delivered to the docket will be transferred to EPA's electronic public
docket. Public comments that are mailed or delivered to the docket will
be scanned and placed in EPA's electronic public docket. Where
practical, physical objects will be photographed, and the photograph
will be placed in EPA's electronic public docket along with a brief
description written by the docket staff.
C. How and to Whom Do I Submit Comments?
You may submit comments electronically, by mail, or through hand
delivery/courier. To ensure proper receipt by EPA, identify the
appropriate docket ID number in the subject line on the first page of
your comment. Please ensure that your comments are submitted within the
specified comment period. Comments received after the close of the
comment period will be marked ``late.'' EPA is not required to consider
these late comments. If you wish to submit CBI or information that is
otherwise protected by statute, please follow the instructions in Unit
I.D. Do not use EPA Dockets or e-mail to submit CBI or information
protected by statute.
1. Electronically. If you submit an electronic comment as
prescribed in this unit, EPA recommends that you include your name,
mailing address, and an e-mail address or other contact information in
the body of your comment. Also include this contact information on the
outside of any disk or CD ROM you submit, and in any cover letter
accompanying the disk or CD ROM. This ensures that you can be
identified as the submitter of the comment and allows EPA to contact
you in case EPA cannot read your comment due to technical difficulties
or needs further information on the substance of your comment. EPA's
policy is that EPA will not edit your comment, and any identifying or
contact information provided in the body of a comment will be included
as part of the comment that is placed in the official public docket,
and made available in EPA's electronic public docket. If EPA cannot
read your comment due to technical difficulties and cannot contact you
for clarification, EPA may not be able to consider your comment.
i. EPA Dockets. Your use of EPA's electronic public docket to
submit comments to EPA electronically is EPA's preferred method for
receiving comments. Go directly to EPA Dockets at http://www.epa.gov/edocket, and follow the online instructions for submitting comments.
Once in the system, select ``search,'' and then key in docket ID number
OPP-2003-0204. The system is an ``anonymous access'' system, which
means EPA will not know your identity, e-mail address, or other contact
information unless you provide it in the body of your comment.
ii. E-mail. Comments may be sent by e-mail to [email protected],
Attention: Docket ID Number OPP-2003-0204. In contrast to EPA's
electronic public docket, EPA's e-mail system is not an ``anonymous
access'' system. If you send an e-mail comment directly to the docket
without going through EPA's electronic public docket, EPA's e-mail
system automatically captures your e-mail address. E-mail addresses
that are automatically captured by EPA's e-mail system are included as
part of the comment that is placed in the official public docket, and
made available in EPA's electronic public docket.
iii. Disk or CD ROM. You may submit comments on a disk or CD ROM
that you mail to the mailing address identified in Unit I.C.2. These
electronic submissions will be accepted in WordPerfect or ASCII file
format. Avoid the use of special characters and any form of encryption.
2. By mail. Send your comments to: Public Information and Records
Integrity Branch (PIRIB) (7502C), Office of Pesticide Programs (OPP),
Environmental Protection Agency, 1200 Pennsylvania Ave., NW.,
Washington, DC 20460-0001, Attention: Docket ID Number OPP-2003-0204.
3. By hand delivery or courier. Deliver your comments to: Public
Information and Records Integrity Branch (PIRIB), Office of Pesticide
Programs (OPP), Environmental Protection Agency, Rm. 119, Crystal Mall
2, 1921 Jefferson Davis Hwy., Arlington, VA, Attention: Docket
ID Number OPP-2003-0204. Such deliveries are only accepted during the
docket's normal hours of operation as identified in Unit I.B.1.
D. How Should I Submit CBI to the Agency?
Do not submit information that you consider to be CBI
electronically through EPA's electronic public docket or by e-mail. You
may claim information that you submit to EPA as CBI by marking any part
or all of that information as CBI (if you submit CBI on disk or CD ROM,
mark the outside of the disk or CD ROM as CBI and then identify
electronically within the disk or CD ROM the specific information that
is 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 docket and EPA's electronic public docket. If you submit
the copy that does not contain CBI on disk or CD ROM, mark the outside
of the disk or CD ROM clearly that it does not contain CBI. Information
not marked as CBI will be included in the public docket and EPA's
electronic public docket without prior
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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
comments:
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
notice.
7. To ensure proper receipt by EPA, be sure to identify the docket
ID 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
Register citation.
II. What Action is the Agency Taking?
EPA has received pesticide petitions as follow proposing the
establishment and/or amendment of regulations for residues of a certain
pesticide chemical 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 FFDCA 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 petitions.
Additional data may be needed before EPA rules on the petitions.
List of Subjects
Environmental protection, Agricultural commodities, Feed additives,
Food additives, Pesticides and pests, Reporting and recordkeeping
requirements.
Dated: June 24, 2003.
Debra Edwards,
Director, Registration Division, Office of Pesticide Programs.
Summary of Petitions
The petitioner's summary of the pesticide petitions is printed
below as required by FFDCA section 408(d)(3). The summary of the
petitions was prepared by the petitioner and represents the view of the
petitioner. The petitions 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.
Interregional Research Project Number 4 (IR-4)
PP 2E6419, 1E6306, 1E6270, 1E6337, 9E5082, 0E6199, and 1E6292
EPA has received pesticide petitions (2E6419, 1E6306, 1E6270,
1E6337, 9E5082, 0E6199, 1E6292) from the IR-4 Project, Center for Minor
Crop Pest Management, Rutgers, The State University of New Jersey, 681
U.S. Highway 1 South, North Brunswick, NJ 08902-3390
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 180.284 by
establishing tolerances for residues of the rodenticide zinc phosphide
in or on the following raw agricultural commodities:
[sbull] PP 2E6419 proposes to establish a tolerance in or on
alfalfa, forage and alfalfa, hay at 0.1 parts per million (ppm).
[sbull] PP 1E6306 proposes a tolerance in or on barley, grain and
barley, hay at 0.05 ppm, and barley, straw at 0.2 ppm.
[sbull] PP 1E6270 proposes a tolerance in or on bean, dry, seed at
0.05 ppm.
[sbull] PP 1E6337 proposes tolerances in or on beet, sugar, roots
at 0.05 ppm and beet, sugar, tops at 0.2 ppm.
[sbull] PP 9E5082 proposes a tolerance in or on potato at 0.05 ppm.
[sbull] PP 0E6199 proposes a tolerance in or on timothy hay and
timothy forage at 0.05 ppm.
[sbull] PP 1E6292 proposes a tolerance in or on wheat grain; wheat,
hay; and wheat, straw at 0.05 ppm.
EPA has determined that these petitions contain 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 support granting of the requests.
Additional data may be needed before EPA rules on the petitions.
A. Toxicological Profile
1. Acute toxicity. The rat acute oral lethal dose (LD)50
values for zinc phosphide technical (89% active ingredient (a.i.)
ranged from 13-35 milligrams/kilogram (mg/kg) body weight (bwt) and
averaged 21 mg/kg. The acute dermal LD50 was greater than
2,000 mg/kg for zinc phosphide technical (94% a.i.) in rabbits. The 4-
hour inhalation lethal concentration (LC)50 on end-use
product was less than 69 mg/cubic meter(m3) air (aerosol).
Zinc phosphide was not irritating dermally to rabbit skin (94% a.i.)
and caused only slight conjunctival redness, chemosis, and discharge in
the rabbit's eyes. Zinc phosphide end-use product did not cause skin
sensitization in guinea pigs. No toxicology studies were identified by
EPA which demonstrated the need for an acute dietary risk assessment
(65 FR 49936).
2. Genotoxicity. Salmonella TA-strains of bacteria were exposed to
zinc phosphide (97% a.i.) suspended in dimethyl sulfoxide (DMSO), at
doses up to 5,000 [mu]g/plate, with and without metabolic activation
(S9). Zinc phosphide was negative for gene mutation in the Ames test.
Mouse lymphoma cells were exposed to zinc phosphide (97% a.i.) with and
without mammalian metabolic activation (S9). Increased mutants at the
thymidine kinase locus (TK) were induced in a dose-dependent manner at
doses of 10 through 80 [mu]g/mL (+/- S9). Zinc phosphide was positive
for gene mutation in this mouse lymphoma assay. Mice were treated with
zinc phosphide (97% a.i.) suspended in corn oil up to severely toxic
levels (150 mg/kg). No increased aberrations (micronuclei) were
induced. Zinc phosphide was negative for mutagenicity in this
micronucleus test.
3. Reproductive and developmental toxicity. The requirements for a
two-generation reproductive toxicity study in rats and a developmental
study on a non-rodent species were waived in the Reregistration
Eligibility Decision (RED Zinc Phosphide, EPA 738-R-98-006, July 1998).
In a developmental toxicity study, the maternal no observed adverse
effect level (NOAEL) was determined to be 2.0 mg/kg and the lowest
effect level (LEL) was 4.0 mg/kg based on mortality. The developmental
NOAEL was at or above 4.0 mg/kg, which was the highest dose tested.
4. Short- and intermediate-term toxicity. Based on the acute dermal
LD50 study in rabbits, no appropriate toxic effects were
identified for risk assessment. In that study no mortalities were
observed at 5,000 mg/kg. At the lowest observed adverse effect level
(LOAEL) of 2,000 mg/kg, there was a decrease in body weight. Based on
the physical properties of the chemical, dermal absorption is expected
to be very low, since zinc phosphide reacts with water and stomach acid
to produce the toxic gas phosphine from oral, but not dermal exposure.
As no endpoint of toxicological concern for dermal
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exposure has been identified, no dermal penetration data were required.
The requirement for an acute inhalation study has been waived; thus,
zinc phosphide has been placed in Toxicity Category I for acute
inhalation exposure.
5. Chronic toxicity. EPA has established the Reference Dose (RfD)
for zinc phosphide at 0.0001 mg/kg/day. This RfD is based on a
subchronic oral study in rats with a NOAEL of 0.1 mg/kg/day and an
uncertainty factor (UF) of 1,000 based on increased mortality, increase
in absolute and relative liver weight and hematological changes at the
LOAEL of 1 mg/kg/day. An uncertainty factor of 100 was applied to
account for both the interspecies extrapolation and intraspecies
variability. An additional UF of 10 was applied to account for the lack
of reproductive data, and the lack of chronic toxicity data in a non-
rodent species (65 FR 49936).
6. Animal metabolism. Since residues are expected to be minimal or
nonexistent, the requirement for a metabolism study with zinc phosphide
has been waived. If new uses result in detectable residues, then this
requirement will be reinstated.
7. Metabolite toxicity. Since residues are expected to be minimal
or nonexistent, the requirement for a metabolism study with zinc
phosphide has been waived.
8. Carcinogenicity. The requirement for carcinogenicity studies has
been waived for zinc phosphide because chronic exposure is expected to
be negligible.
9. Endocrine disruption. There are no data available to suggest
that zinc phosphide will adversely affect the immune or endocrine
systems.
B. Exposures and Risks
1. From food and feed uses. Tolerances have been established (40
CFR 180.284) for the residues of phosphine resulting from the use of
zinc phosphide, in or on a variety of raw agricultural commodities at
levels ranging from 0.01 ppm in or on grapes to 0.1 ppm in or on
grasses (rangeland). Zinc phosphide uses on grapes, pasture, and
rangeland grasses, sugar beets, and sugar cane are classified as food
uses. Currently registered uses on alfalfa, barley, wheat, and timothy
are classified as non-food uses. The recently submitted petitions seek
to amend the method of applications for these crops as follows:
i. Alfalfa; from underground or in burrow builder, or bait box use
to above ground broadcast application. The proposed application would
limit the timing of application to the period during dormant season
(Idaho), or following removal of all cut alfalfa and prior to new
growth obtaining 2 to 3 inches (California and Idaho),
ii. Barley and wheat; from dormant season use (underground or in
burrow builders) to above ground broadcast application prior to grain
head formation.
iii. Timothy; from dormant season use, with no animal grazing, to
use during crop dormancy but permitting livestock grazing after 158
days. These types of applications are classified as food uses;
therefore, a tolerance is required. There is no reasonable expectation
of secondary residues in meat, milk, poultry, or eggs. Any residues of
zinc phosphide ingested by livestock would be metabolized to naturally
occurring phosphorous compounds. Risk assessments were conducted by EPA
to assess dietary exposures and risks from zinc phosphide applied as
non-food use as follows: Acute and chronic exposure and risk. 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. Currently,
it is not known whether the proposed use of zinc phosphide on the
subject crops will result in acute or chronic human dietary exposure to
zinc phosphide.
However, the petitioner notes the following:
i. Zinc phosphide is not systemic (i.e., it will not move to other
portions of the plant such as roots and affect a root crop such as
potatoes or sugar beets).
ii. Residues of phosphine are less than the limit of quantification
(0.05) in wheat and barley grain, in dry beans, in potatoes, in sugar
beet roots, and in timothy hay.
iii. The grain and sugar beet roots will be processed prior to
human consumption.
iv. There is no expectation of secondary residues in meat, milk,
poultry, and eggs as a result of the registered and proposed uses.
2. From drinking water. Zinc phosphide degrades rapidly to
phosphine and zinc ions both of which adsorb strongly to soil and are
common nutrients in soil. Zinc phosphide and its degradation products
appear to have low potential for ground water and surface water
contamination. Therefore, dietary exposure is not expected from either
ground water or surface water fed drinking water.
3. From non-dietary exposure. Zinc phosphide is currently
registered for use on residential non-food sites. A detailed
residential exposure assessment is contained in the RED for zinc
phosphide (RED Zinc Phosphide, EPA 738-R-98-006, July 1998). The
residential exposure assessment evaluated exposure from accidental
ingestion of zinc phosphide. No other residential exposure assessment
was required. It is stated in the RED that the Agency believes that
``accidental ingestion'' of zinc phosphide baits should not be included
in the FQPA determination for tolerance setting.
4. 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
considers ``available information'' concerning the cumulative effects
of a particular pesticide's residues and ``other substances that have a
common mechanism of toxicity.'' Zinc phosphide, aluminum phosphide, and
magnesium phosphide all generate phosphine gas. However, the toxicity
from phosphine gas is an acute effect and is readily eliminated from
the body. Aluminum and magnesium phosphide, unlike zinc phosphide which
is a bait, are used in fumigations. Exposure to phosphine gas from both
bait and fumigation treatments is highly unlikely. It is unclear
whether zinc phosphide has a common mechanism of toxicity with other
substances or how to include this pesticide in a cumulative risk
assessment. Unlike other pesticides, where a cumulative risk approach
is based on a common mechanism of toxicity, zinc phosphide does not
appear to produce a toxic metabolite produced by other substances.
C. Aggregate Exposure
1. Acute and chronic risk. There are currently no drinking water,
residential, or dietary components to acute and chronic aggregate
exposure to zinc phosphide residues. Thus, acute and chronic aggregate
exposure assessments were not required in the RED (Zinc Phosphide, EPA
738-R-98-006, July 1998).
2. Short- and intermediate-term risk. Short- and intermediate-term
aggregate exposure takes into account chronic dietary food and water
(considered to be a background exposure level) plus indoor and outdoor
residential exposure. No short- or intermediate-term dermal, oral or
inhalation toxicological endpoints were identified for zinc phosphide.
Thus, no short- or intermediate-term risk assessments were required in
the RED (Zinc Phosphide, EPA 738-R-98-006, July 1998).
3. Aggregate cancer risk for U.S. population. Although zinc
phosphide is registered for use on food crops, no chronic toxicity or
carcinogenicity
[[Page 40943]]
studies were required because chronic exposure to zinc phosphide or its
byproducts were considered to be negligible. Thus, data are not
available to classify zinc phosphide in terms of carcinogenicity and a
cancer risk assessment was not performed.
D. Determination of Safety
1. U.S. population. The RED set the RfD at 0.0001. EPA generally
has no concerns for exposures below 100% of the RfD, because the RfD
represents the level at or below which daily aggregate exposure over a
lifetime will not pose appreciable risks to human health.
2. Infants and children. The available data base for zinc phosphide
does not indicate a potential for an increased sensitivity to infants
or children; however it does not include a two-generation reproductive
toxicity study in rats or a developmental toxicity study for a non-
rodent species. The available data provided no indication of increased
sensitivity of fetal rats to in utero exposure to zinc phosphide. The
prenatal exposure developmental toxicity study in rats demonstrated no
developmental effects at the highest dose tested (4.0 mg/kg/day) which
was maternally toxic. There was no assessment of in utero exposure to
non-rodents (rabbits), nor was there an assessment of early postnatal
exposure. The EPA did not require these studies because exposure from
food sources is expected to be minimal to non-existent. The additional
uncertainty factor (referred to in Section A.5.) will also accommodate
the inability to assess the potential for increased sensitivity of
infants and children, because of the lack of sufficient animal data on
in utero and early postnatal exposure to zinc phosphide (a prenatal
developmental toxicity study in rabbits and a two-generation
reproductive toxicity study in rats). Although residue studies show
there were quantifiable residues in sugarcane, sugar beets, and
grasses, these commodities are not direct human foods and no dietary
consumption is expected. EPA has determined that there is no likelihood
of residues of zinc phosphide occurring in any processed commodities.
Also, there is no likelihood of residues of zinc phosphide or phosphine
being found through transfer of residues on grasses to meat and milk.
Based upon the likelihood that residues of zinc phosphide will not
occur in processed commodities, milk and meat, there is a reasonable
certainty that no harm will result from aggregate exposure to zinc
phosphide residues.
E. Other Considerations
1. Metabolism in plants and animals. The nature of the residue in
plants is adequately understood. The residue of concern is zinc
phosphide measured as phosphine. There is no expectation of secondary
residues in meat, milk, poultry, and eggs as a result of the registered
uses. Residues of zinc phosphide ingested by livestock would be
immediately converted to phosphine and metabolized to naturally
occurring phosphorous compounds.
2. Analytical enforcement methodology. Adequate enforcement
methodology (colorimetric and GLC/FPD) is available (Pesticide
Analytical Method II under aluminum phosphide) to enforce the tolerance
expression. Residues were less than the limit of quantification in all
raw agricultural commodities except for sugar beet tops (0.05 ppm for
alfalfa, barley, grain and hay, dry beans, potatoes, sugar beet roots,
timothy and wheat; 0.1 for barley straw),
i. Barley grown in the state of Idaho was treated with two
applications of zinc phosphide at approximately 0.12 lb a.i./A per
application, 23 to 28 days apart, and were harvested 50 or 60 days
after the last application. Barley was also harvested 50 days following
two applications at 0.96 lb a.i./A (8X the proposed application rate).
Residues were less than the limit of quantification for barley grain
and hay (0.05 ppm) and straw (0.1). Because no residues were found in
samples treated at the 8X rate, no processing study is needed.
ii. Dry beans grown in the state of Idaho were treated with one
application of zinc phosphide at approximately 0.12 lb a.i./A, and were
harvested 31 days after the application and allowed to dry in the
field. Seven days after harvesting the beans were thrashed and samples
taken. Residues were less than the limit of quantification (0.05 ppm)
on this commodity.
iii. Potatoes grown in the state of Idaho were treated with one
application of zinc phosphide at approximately 0.2 lb a.i./A, and were
harvested 28 to 31 days later. Potatoes were also harvested 28 to 31
days later following an application at 1.0 lb a.i./A (5x the proposed
application rate). Residues were less than the limit of quantification
(0.05 ppm) on this commodity. Because no residues were found in samples
treated at the 5X rate, no processing study is needed.
iv. Sugar beets grown in the state of Idaho were harvested 27 to 29
days following two treatments of zinc phosphide at approximately 0.2 lb
a.i./A. Sugar beets were also harvested 27 to 29 days following two
treatments of zinc phosphide at approximately 4 lb a.i./A (20X the
proposed application rate). Residues were less than the limit of
quantification (0.05 ppm) on sugar beet roots. Sugar beet tops
contained some residue and a tolerance of 0.2 ppm is being proposed for
sugar beet tops. Because no residues were found in roots treated at the
exaggerated rate, there is no need for data from processed roots.
(OPPTS Harmonized Guideline 860.1520(f)(3)(iii)).
v. Timothy hay grown in the state of Washington was harvested 117
days following two treatments of zinc phosphide. The first treatment
was at approximately 0.2 lb a.i./A and the second treatment was at
approximately 0.4 lb a.i./A (due to applicator error). The hay was
allowed to dry in the field after harvest. Residues were less than the
limit of quantification (0.05 ppm) on timothy hay and timothy forage at
harvest.
vi. Wheat grown in the state of Idaho was treated with two
applications of zinc phosphide at approximately 0.12 lb a.i./A per
application, 22 to 28 days apart, and were harvested 56 to 60 days
after the last application. Wheat was also harvested 56 days following
two applications at 0.96 lb a.i./A (8X the proposed application rate).
Residues were less than the limit of quantification (0.05 ppm) for
wheat grain, hay and straw. Because no residues were found in samples
treated at the 8X rate, no processing study is needed.
vii. Fresh alfalfa grown in the state of California was harvested
32 days following one treatment of zinc phosphide at approximately 0.2
lb a.i./A. Fresh alfalfa was also harvested 32 days following one
treatment of zinc phosphide at approximate 0.4 lbs a.i./A (2X the
proposed application rate). Residues were less than the limit of
quantification (0.05 ppm) on fresh alfalfa.
viii. Alfalfa hay and fresh alfalfa grown in the state of Nebraska
were harvested 21 days following one treatment of zinc phosphide at
approximately 0.2 lbs a.i./A. Residues were less than the limit of
quantification (0.05 ppm) on alfalfa hay and fresh alfalfa.
ix. Alfalfa hay and alfalfa forage grown in the state of Idaho were
harvested three times: 28-32 days, 78-83 days, and 121-129 days
following the second of two treatments of zinc phosphide at
approximately 0.2 lbs a.i./A. Residues were less than the limit of
quantification (0.05 ppm) on alfalfa hay and alfalfa forage. (Petition
for residue tolerance for alfalfa use in Idaho soon to be submitted.)
[[Page 40944]]
F. International Residue Limits
No CODEX, Canadian or Mexican maximum residue levels have been
established for zinc phosphide.
G. Rotational Crop Restrictions
Data for confined accumulation in rotational crops have been
waived because the physical properties of zinc phosphide precludes
transfer of residues to rotated crops (Zinc Phosphide RED, EPA 738-R-
98-006, July 1998). Thus, rotational crop restrictions are not
required.
[FR Doc. 03-17104 Filed 7-8-03; 8:45 am]
BILLING CODE 6560-50-S