pelargonic acid; Pesticide Tolerance Petition 1/97
CHEMICAL PROFILES/HERBICIDE & GROWTH REGULATOR/pelargonic acid
ENVIRONMENTAL PROTECTION AGENCY
Mycogen Corporation; Pesticide Tolerance Petition Filing
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of filing.
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: firstname.lastname@example.org. 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:
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
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<Register> 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
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
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<Register> 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
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
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
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
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
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 <plus- minus>)
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 <plus-minus>) 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.
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
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
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
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@example.com
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 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]
[Federal Register: January 24, 1997 (Volume 62, Number 16)] [Notices]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]