[Federal Register Volume 62, Number 16 (Friday, January 24, 1997)]
[Notices]
[Pages 3688-3691]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1753]
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ENVIRONMENTAL PROTECTION AGENCY
[PF-685; FRL-5579-3]
Mycogen Corporation; Pesticide Tolerance Petition Filing
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of filing.
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SUMMARY: This notice announces the filing of a pesticide petition
proposing a regulation establishing an exemption from the requirement
of a tolerance for residues of the pesticide pelargonic acid on all raw
agricultural commodities. This notice includes a summary of the
petition that was prepared by the petitioner, Mycogen Corporation.
DATES: Comments, identified by the docket control number [PF-685], must
be received by EPA on or before February 24, 1997.
ADDRESSES: By mail, submit written comments to: Public Response and
Program Resources Branch, Field Operations Division (7506C), Office of
Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460. In person, bring comments to: Rm. 1132, Crystal
Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
Comments and data may also be submitted electronically by sending
electronic mail (e-mail) to: [email protected]. Electronic
comments must be submitted as an ASCII file avoiding the use of special
characters and any form of encryption. Comments and data will also be
accepted on disks in WordPerfect 5.1 file format or ASCII file format.
All comments and data in electronic form must be identified by docket
number [PF-685]. No ``Confidential Business Information'' (CBI) should
be submitted through e-mail. Electronic comments on this notice of
filing may be filed online at many Federal Depository Libraries.
Additional information on electronic submissions can be found in Unit
II. of this document.
Information submitted as a comment concerning this document may be
claimed confidential 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. A copy of the comment that
does not contain CBI must be submitted for inclusion in the public
record. Information not marked confidential may be disclosed publicly
by EPA without prior notice. All written comments will be available for
public inspection in Rm. 1132 at the address given above, from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays.
FOR FURTHER INFORMATION CONTACT: Michael Mendelsohn, Biopesticides and
Pollution Prevention Division (7501W), Office of Pesticide Programs,
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460.
Office location, telephone number, and e-mail address: 5th Floor, CS
#1, 2805 Jefferson Davis Highway, Arlington, VA, 703-308-8715; e-mail:
[email protected].
SUPPLEMENTARY INFORMATION: EPA has received pesticide petition (PP)
6F4625 from Mycogen Corporation, 4980 Carroll Canyon Road, San Diego,
CA 92121. The petition proposes, pursuant to section 408 of the Federal
Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a, to amend 40 CFR
part 180 by establishing an exemption from the requirement of a
tolerance for residues of pelargonic acid on all raw agricultural
commodities. EPA has determined that the petition contains 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.
Mycogen has stated that an analytical method for the detection and
measurement of pelargonic acid residues is not necessary to protect the
public health and environment. They state that the natural occurrence
of pelargonic acid in our food supply and environment, and the rapid
metabolism and degradation of pelargonic acid to background levels in
humans, plants and soil, eliminate the need to quantify pelargonic acid
residues.
As required by section 408(d) of the FFDCA, as recently amended by
the Food Quality Protection Act, Mycogen included in the petition a
summary of the petition and authorization for the summary to be
published in the Federal Register in a notice of receipt of the
petition. The summary represents the views of Mycogen; EPA, as
mentioned above, is in the process of evaluating the petition. As
required by section 408(d)(3) EPA is including the summary as a part of
this notice of filing. EPA may have made minor edits to the summary for
the purpose of clarity.
I. Petition Summary
This unit summarizes information cited by Mycogen to support the
proposed tolerance.
A. Pelargonic Acid Uses
Pelargonic acid is currently used as the active ingredient in two
unique pesticide products. First, it is used as a contact, non-
selective, broadspectrum, foliar-applied herbicide. As the active
ingredient in Scythe Herbicide (EPA Reg. No. 53219-7),
registered by EPA for non-crop uses on April 7, 1994, pelargonic acid
will only control actively growing emerged green vegetation. Pelargonic
acid provides burndown of both annual and perennial broadleaf and grass
weeds, as well as most mosses and other cryptogams. The spray quickly
penetrates plant tissue and disrupts normal cell membrane permeability
and cellular physiology. The disruption of the cell membrane results in
cell leakage and death of all contacted tissue. The product does not
translocate, and it will burn only those plant parts that make contact
with spray solution. Scythe provides no residual
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weed control; therefore, repeat treatments may be necessary for new
plants emerging from seed or regrowth of treated vegetation.
Scythe Herbicide contains as the active ingredient 57 percent
pelargonic acid and 3 percent related fatty acids (C6 - C12).
One gallon of Scythe contains 4.2 pounds (lbs) of pelargonic acid. The
application rate will range from 3 percent to 10 percent v/v delivered
at 75 to 200 gallons of spray solution per acre through boom, hand-
held, or high volume equipment. Therefore, the rate of use of
pelargonic acid will be 9.45 lbs to 84 lbs per acre. Combinations with
selected products may further reduce the application rate to a low 0.78
lbs to 2.1 lbs per acre (0.25 percent solution in 75 or 200 gallons
spray per acre).
Second, pelargonic acid is used as a fruit blossom thinner that
promotes return bloom (annual bearing) and increased fruit size and
quality in apple and pear. Thinex Blossom Thinner (EPA Reg.
No. 53219-11) was registered as a biochemical pesticide due to the
natural occurrence of pelargonic acid, the low use rates and the unique
non-toxic mode of action. Thinex works on contact by damaging the
stigma or female flower part of the blossom, thus preventing
pollination of a certain percentage of flowers. A blossom that has
already been fertilized at the time of application will be undamaged by
Thinex. No more than 2 applications per year are made. On February 14,
1996, pelargonic acid was exempt under 40 CFR 180.1159 from the
requirement of a tolerance when used as a blossom thinning agent on
apple and pear.
Thinex Blossom Thinner contains as the active ingredient 57 percent
pelargonic acid and 3 percent related fatty acids (C6 - C12).
The application rate as a blossom thinner ranges from 0.5 pints to 4
pints of product to make 100 gallons of spray solution. One hundred to
400 gallons of spray solution per acre may be used. Therefore, the rate
of use of pelargonic acid as a blossom thinning agent ranges from a low
0.26 lbs to a high 8.4 lbs per acre.
B. Product Identity/Chemistry
Pelargonic acid (C8H17COOH), a nine-carbon straight-chain
fatty acid commonly referred to as nonanoic acid, is a naturally-
occurring fatty acid found in the environment and in our food supply.
Pelargonic acid has been found to occur naturally in low
concentrations in soil. The degradation of pelargonic acid applied to
soil occurs very rapidly by microbial means, not through hydrolysis or
photolysis. Degradation occurs under aerobic conditions with beta-
oxidation being the principal pathway of metabolism.
Pelargonic acid has been shown to occur naturally in our food
supply. For example, it has been identified in grapes, cheese and milk
at levels from 10 parts per million (ppm) to 400 ppm. Some literature
references cite its natural occurrence in soybeans (trace levels),
oranges (130 ppm), beans (trace levels), tobacco (0.27 ppm) and
potatoes (1.18 ppm). In a cross-section of apple varieties analyzed by
Mycogen, pelargonic acid was found at levels from 20 parts per billion
(ppb) to 320 ppb.
Fatty acids, including pelargonic acid, are metabolized in
mammalian systems to produce energy. The oxidative degradation of fatty
acids is a central metabolic pathway in humans, animals and plants.
Fatty acids of varying chain lengths are metabolized into two-carbon
fragments through a sequence of enzyme-catalyzed reactions. The
metabolic products are then incorporated into fats, carbohydrates and
amino acids.
The magnitude of pelargonic acid residues from applications of
Scythe Herbicide anticipated at time of harvest will be insignificant
beyond naturally-occurring levels and to normal dietary exposure.
Applications of Scythe Herbicide will not directly contact desirable
food commodities since exposure will be intentionally avoided by the
grower because crop damage may result. Any residues of pelargonic acid
on food commodities will only occur as a result of spray drift, thus
minimizing residues of pelargonic acid on the food commodity.
An analytical method for detecting and measuring the levels of
pelargonic acid residue is not necessary to protect the public health
and environment. The natural occurrence of pelargonic acid in our food
supply and environment, and the rapid metabolism and degradation of
pelargonic acid to background levels in humans, plants and soil,
eliminate the need to quantify pelargonic acid residue from
applications as a herbicide or a blossom thinner.
C. Mammalian Toxicological Profile
Mycogen has submitted to EPA a comprehensive toxicology data
package and referenced several published articles concluding that
residues of pelargonic acid will be safe to human health.
Although a significant concentration of pelargonic acid can be
irritating to eyes and skin, toxicology data confirms that exposure to
residues of pelargonic acid beyond naturally occurring background
levels will be practically non-toxic to human health. The following
mammalian toxicity studies have been conducted to support the tolerance
exemption for residues of pelargonic acid:
Acute Oral LD50: >5000 mg/kg
Acute Dermal LD50: >2000 mg/kg
Acute Inhalation LC50: >1.244 mg/L
Dermal Irritation (Rat): Severely Irritating
Eye Irritation (Rabbit): Severely Irritating
Skin Sensitization (Guinea Pig): Not sensitizing
A range finding test to determine dosing concentrations for a 90-
Day Rat Oral Toxicity study produced no adverse effects from pelargonic
acid at any dose level for 3 weeks, including the highest dose of
20,000 ppm (2 percent), or 1,834 mg/kg/day, for a period of 2 weeks.
A developmental toxicity screen study in rats produced a NOEL of
1,500 mg/kg/day (only dose tested). Pelargonic acid was tested at one
dose administered by gavage in corn oil to 22 CD rats (20 pregnant) on
days 6 through 15 of gestation. No evidence of maternal or
developmental toxicity was seen.
A chronic dermal toxicity study in mice resulted in no evidence of
severe dermal or systemic toxicity. Fifty mice were treated twice-
weekly with 50 mg doses of undiluted pelargonic acid for 80 weeks.
Histopathology revealed no tumors of the skin or the internal organs.
A gene mutation assay in mouse lymphoma cells (L5178Y TK ) concluded that pelargonic acid was negative for inducing
mutations without metabolic activation, and was considered weakly
positive for inducing mutations at the TK locus of culture mouse
(L5178Y TK ) cells in the presence of S9-induced metabolic
activation. Mutations were induced at levels greater than or equal to
50 mg/ml. However, this occurred in the presence of increasing
moderate-to-severe cytotoxicity and small colony development and may
reflect gross chromosomal changes or damage rather than actual
mutational changes within the TK gene locus.
In an in-vivo mouse micronucleus assay, groups of ICR mice (15/sex/
dose) were administered single oral doses of 1,250, 2,500, or 5,000 mg/
kg pelargonic acid. The bone marrow cells were harvested 24, 48, and 72
hours post-treatment. No significant increases in the frequency of
micronucleated polychromatic erythrocytes (PCEs) were observed in
either sex at any dose; thus, pelargonic acid was negative in the
micronucleus assay.
A reverse gene mutation assay (Ames Test) concluded that pelargonic
acid was not mutagenic under the conditions of the study.
[[Page 3690]]
D. Aggregate Exposure
Pelargonic acid is a naturally-occurring fatty acid found in our
food supply. Mycogen Corporation has estimated the potential worst case
dietary exposure of pelargonic acid beyond existing natural background
levels after an application of Scythe Herbicide between grape vine
rows. The commodity grape was selected because the use of Scythe
Herbicide between grape vine rows is a representative and major use
pattern intended for the product. In an effort to make a worst case
scenario for residue calculations, Mycogen has suggested a 10 percent
deposition on the crop, even though such a drift rate will be
intentionally avoided by the grower because crop damage may result.
Drift deposition would likely be less than 1 percent of applied spray
volume.
The worst case human daily consumption level of pelargonic acid
from treated grapes has been estimated to be 0.397 mg/kg/day. This
exposure dose after applications of Scythe Herbicide must be compared
to the highest dose level tested in the dietary range-finding
toxicology study. In this study, a daily feeding dose of 1,834 mg/kg/
day (20,000 ppm) did not produce any signs of toxicity or abnormalities
for a period of 2 weeks.
Exposure to drinking water will be minimal. Scythe Herbicide will
not be applied directly to water. The proposed label includes
applications to dry ditches, dry canals, ditch banks, and for use above
the water line or after draw-down of agricultural irrigation water and
ditch systems, industrial ponds and disposal systems, and impounded
water areas. Taking potential spray drift into consideration, the rapid
degradation of pelargonic acid to naturally-occurring background levels
in our environment will mitigate the exposure of residues to drinking
water to insignificant amounts. In addition, the degradation of
pelargonic acid will ensure that no contamination to groundwater will
occur.
If residues of pelargonic acid do occur in food or in drinking
water, information on the metabolism of fatty acids in the body
confirms that residues of pelargonic acid would present minimal risk to
humans. Fatty acids are digested in mammalian systems through normal
metabolic pathways. While pelargonic acid is not as widespread in our
diet as other fatty acids, the only difference is that most dietary
fatty acids have even-numbered carbon chains and are ingested initially
in the form of triglycerides. It is likely that pelargonic acid, when
it is absorbed from the gastrointestinal tract into the blood, would be
treated little differently from the free fatty acids released from
adipose tissue.
Non-dietary exposure of pelargonic acid will be mitigated through
the use of proper personal protective equipment. For non-occupational
uses or exposure to sites not associated with food or drinking water,
data on the natural occurrence and rapid microbiological degradation of
pelargonic acid in the environment confirms that exposure will be
minimal. EPA has waived all environmental fate data requirements for
the current registration of Scythe Herbicide.
E. Cumulative Exposure
No cumulative exposure through other pesticides and substances with
common mode of toxicity is expected. Pelargonic acid has a unique mode
of action. Residues will not increase or sustain as a result of
exposure to other materials. Pelargonic acid will degrade by microbial
action to background levels over a period of 24 - 48 hours regardless
of contact with substances either through pesticide tank mixing or
exposure to other chemical residues in the environment. Normal use
patterns will not lead to accumulation of pelargonic acid in the
environment.
F. Safety Determination
Mycogen believes that the use of pelargonic acid as a naturally-
occurring, lower toxicity, environmentally compatible material fits
with EPA's objective to register reduced risk pesticides. The common
dietary intake of the U.S. population includes low concentrations of
naturally-occurring fatty acids, including pelargonic acid. The rapid
environmental breakdown of pelargonic acid will significantly decrease
any residues as a result of applications from Scythe Herbicide. Mycogen
believes that under worst case exposure calculations, and based on
established toxicology data, any increased levels of pelargonic acid
will present no adverse effects to the consumer.
Mycogen believes that a determination of safety for infants and
children can be made due to the insignificant exposure expected beyond
naturally-occurring background levels, the fact that fatty acids are
digested in mammalian systems through normal metabolic pathways, and
the toxicology data base concludes that pelargonic acid is practically
non-toxic when administered orally. The developmental toxicity screen
study in rats produced a NOEL of 1,500 mg/kg/day (only dose tested),
and no evidence of maternal or developmental toxicity was seen.
G. Existing Tolerances
Pelargonic acid is exempt under 40 CFR 180.1159 from the
requirement of a tolerance when used as a blossom thinning agent on
apple and pear. Pelargonic acid has been added to the Food and Drug
Administration's list of approved chemicals that may be safely used in
washing or to assist in the lye peeling of fruits and vegetables in
concentrations of up to 1 percent (21 CFR 173.315). The same use is
cleared by the United States Department of Agriculture under the USDA
List of Authorized Substances, 1990, 7 CFR 5.14, Fruit & Vegetable
Washing Compounds. In addition, pelargonic acid is cleared by the Food
and Drug Administration as a sanitizer solution to be used on food-
contact articles [21 CFR 178.1010(b) (42)], or as a synthetic food
flavoring agent and adjuvant (21 CFR 172.515).
II. Administrative Matters
Interested persons are invited to submit comments on this notice of
filing. Comments must bear a notation indicating the document control
number, [PF-685]. All written comments filed in response to this
petition will be available in the Public Response and Program Resources
Branch, at the address given above from 8:30 a.m. to 4 p.m., Monday
through Friday, except legal holidays.
A record has been established for this notice of filing under
docket number [PF-685] (including comments and data submitted
electronically as described below). A public version of this record,
including printed, paper versions of electronic comments, which does
not include any information claimed as CBI, is available for inspection
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal
holidays. The public record is located in Rm. 1132 of the Public
Response and Program Resources Branch, Field Operations Division
(7506C), Office of Pesticide Programs, Environmental Protection Agency,
Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
Electronic comments can be sent directly to EPA at:
[email protected]
Electronic comments must be submitted as an ASCII file avoiding the
use of special characters and any form of encryption.
The official record for this notice of filing, as well as the
public version, as described above will be kept in paper form.
Accordingly, EPA will transfer all
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comments received electronically into printed, paper form as they are
received and will place the paper copies in the official rulemaking
record which will also include all comments submitted directly in
writing. The official record is the paper record maintained at the
address in ``ADDRESSES'' at the beginning of this document.
Authority: 21 U.S.C. 346a.
List of Subjects
Environmental protection, Agricultural commodities, Pesticides and
pests, Reporting and recordkeeping requirements.
Dated: January 16, 1997.
Flora Chow,
Acting Director, Biopesticides and Pollution Prevention Division,
Office of Pesticide Programs.
[FR Doc. 97-1753 Filed 1-23-97; 8:45 am]
BILLING CODE 6560-50-F