United Stat« Qfflo* of Pattiddw and Toxic Submnon
Environmontal Protactlon Qffle* of P«ldd» Programs (TS-766C)
Agency WMhington. DC 20460
540/FS-88-090
x°/EPA Pesticide
Fact Sheet
Name of Chemical: Quizaiofop
Reason for Issuance: Registration of New Chemical
Date Issued: June 10, 1988
Facf Sheet Number: ies
1. Description of Chemical
Generic Name: Ethyl 2-[4-(6-chloroquinoxalin-2-yl oxy)phenoxy]propanoate
Common Name: Quizaiofop Ethyl, DPX-Y6202
Trade Name: DuPont Assure Herbicide
EPA Shaughnessy Code: 128201
Chemical Abstracts Service (CAS) Number: 76578-14-8
Year of Initial Registration: 1988
Pesticide Type: Herbicide
Chemical Family: Phenoxy Propionic Ester
U.S. and Foreign Producers: E.I. du Pont de Nemours & Company, Inc.
Nissan Chemical Industries, Ltd.
2. Use Patterns and Formulations
Application Sites: Terrestrial food crops
Major Crops Treated: Soybeans
Types and Methods of Application: Foliar, applied broadcast by air
or ground equipment for control of annual and perennial grasses.
It is applied postemergence to both crops and grasses.
Application Rates: Up to 4 ounces active ingredient per acre.
Types of Formulations: 9.5% EC
Usual Carrier: Water
3. Science Findings
Summary Science Statement: The submitted data are acceptable to the
Agency. Quizalofop ethyl has low acute toxicity, Category III for
acute oral and acute inhalation (technical) and primary eye
irritation (formulation), and Category IV for acute oral, acute
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dermal, and primary dermal (formulation), acute dernital, primary
dermal, delayed hypersensitivity, and primary eye irritation
(technical). It was not oncogenic to rats or mice [ increases in
liver tumors occurred at highest dose which exceeded the maximum
tolerated dose (MTD) I and not teratogenic to rats or rabbits and
not rnutagenic. Quizalofop ethyl is practically nontoxic to birds
or honey bees; highly toxic to freshwater fish, very highly toxic
to invertebrates, moderately toxic to marine fish and very toxic
to marine invertebrates. It has a low potential to leach and
contaminate ground water and does not accumulate in fish. The
nature of the residues in plants and animals is adequately
understood and adequate methodology is available for enforcement
of tolerances in soybeans, processed soybean food/feed items and
meat, milk, poultry, and eggs.
Chemical Characteristics :
Physical State: Technical, solid; 9.5% EC, liquid
Color: Technical, white; 9.5% EC, amber
Odor: Technical, None; 9.5% EC, aromatic/petroleum
Melting Point: 91 °C
Specific Gravity: Technical, 1.35 grams per cubic centimeter
(g/cc 3 ); 9.5% EC, 1.01 g/cc 3
Molecular Weight: 372.81
Solubility: In distilled water at 25 °C, .3 milligrams/liter
(mg/L); in 0.05 N sodium phosphate buffer at 25 °C as a function
of PH:
pH 5.4 0.34 ing/L
pH 7.1 0.31 mg/L
pH 9.0 0.29 mg/L
pH 10.4 0.31 mg/L
In organic solvents at 25 °C:
Acetone 110 g/L
Acetoriitrile 86 g/L
Ethanol 9 g/L
Benzene 290 g/L
Xylene 120 g/L
N—hexane 2.6 g/L
Dioxane 350 g/L
Unusual Handling Characteristics: No special handling needed.
Toxicology Characteristics :
Acute Studies (9.5% EC)
Acute Oral Toxicity — Rat: 6600 mg/kg (males), 5700 mg/kg
(females); Toxicity Category IV
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Acute Dermal Toxicity — Rabbit: > 5000 mg/kg; Toxicity Category IV
Primary Dermal Irritation — Rabbit: Not a primary skin irritant;
Toxicity Category IV
Primary Eye Irritation — Rabbit: Mild irritant; Toxicity
Category III
Acute Studies (Technical)
Acute Oral Toxicity - Rat: 1670 mg/kg (males), 1480 mg/kg
(females); Toxicity Category III
Acute Derinal Toxicity - Rabbit: > 5000 mg/kg; Toxicity
Category IV
Acute Inhalation - Rat: 4.8 to 5.8 mg/L; Toxicity Category III
Delayed Hypersensitivity — Guinea Pig: Not a sensitizer.
Primary Eye Irritation — Rabbit: Not an eye irritant; Toxicity
Category IV
Primary Dermal Irritation — Not a skin irritant; Toxicity
Category IV
Chronic Toxicology:
90—Day Feeding Study - Rat:
No—observed--effect level (NOEL) = 2 milligram/kilogram/day
(mg/kg/day) lowest dose tested (LDT)
90—Day Feeding Study — Mouse:
NOEL less than (<) 15 mg/kg/day (LDT)
6-Month Feeding Study - Dog:
NOEL = 2.5 mg/kg/day
2-Year Chronic Feeding/Oncogenicity Study - Rat:
Systemic NOEL = 0.9 mg/kg/day
Systemic lowest effect level (LEL) = 3.7 mg/kg/day
No oncogenic effects up to and including 15.5 mg/kg/day (highest
dose tested (HDT)]
18—Month Chronic Feeding/Oncogenicity Study — Mouse:
Systemic NOEL = 12 mg/kg/day
Systemic LEL = 48 mg/kg/day
No oncogenic effects up to and including 12 mg/kg/day; an
effect (increase in combined benign and malignant liver tumors)
occurred at the HDT which exceeded the MTD.
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1-Year F eding Study - I g:
NOEL = 10 mg/kg/day (HUT)
rato1ogy Study - Rat:
NOEL> 300 mg/kg/day (HIYT)
Is.b teratogenic effects at 300 mg/kg/day (H!YT)
Terato1o r Stt y - Rabbit:
Maternal toxic NOEL = 20 mg/kg/day
Maternal toxic LEL = 60 mg/kg/day (HDT)
Deve1op nta1 NOEL = 60 mg/kg/day (HDT)
2-Generation Reproduction — Rat:
F totoxic NOEL = 1.25 mg/kg/day
Maternal NOEL = 5 mgjkg/day
Develoiirental NOEL = 1.25 mg/kg/day
No reproductive effects up to 20 mg/kg/day (HUT)
Mutagenicity ( Sa1u nella typh1n irium) : Negative
Mutagenicity, (liranosomal Aberrations (CHO) In Vitro : Negative
Mutagenicity, Unscheduled DNA Synthesis (Rat): Negative, not
mu tagenic
Metaboli — Rat: Readily absorbed fran gastrointestinal tract
and excreted rapidly.
Major Routes of Exposure :
The major route of exposure is via eye contact (formulation) and acute
oral and acute inhalation (technical).
Physiological and Bioch nical Characteristics :
Pbliar Absorption: Rapid.
Translocation: Syst nic after absorption by foliage.
T chani$n of Pesticidal Action: Inhibition of fatty acid biosynthesis
in susceptible plants. Potential to Contaminate Ground Water:
Rased on the low potential for leaching, quizalofop ethyl has a
low potential to contaminate ground water.
? taboliam in Plants arid Pninals: tabo1ized to several
nonherbicidal carpounds.
Persistence in Animals and Plants: toes not persist in either
animals or plants.
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Environmental Characteristics :
Absorption and Leaching in Basic Soil Types: DPX-Y6202 was poorly
absorbed in two sandy loam and two silt loam soils and characterized
as immobile. DPX—y6202 and its acid metabolite are immobile to
moderately mobile and have a low potential to leach.
Microbial Breakdown: Rapidly metabolized to DPX-acid which further
degraded to phenols and CO 2 .
Loss from Decomposition and Volatilization: None expected.
Bioaccumulatio n in Fish: Does not accumulate in fish.
Resultant Average Persistence: Half—life of 139 and 145 days in
silty clay loam and silt loam, respectively.
Exposure of Humans and Nontarget Organisms to Pesticide or
Degradates: Human risk from exposure is minimal because of low
acute toxicity (Categories III and IV). Nontarget organism risk
is minimal because maximum expected residues on soil and water do
not approach the toxicity values for organisms tested.
Ecological Characteristics :
Avian Acute Oral Toxicity - Mallard Duck: > 2000 mg/kg.
Avian 8—Day Dietary Toxicity — Mallard Duck: 5000 ppm.
Avian 8—Day Dietary Toxicity - Bobwhite Quail: 5620 ppm.
Fish Acute 96—Hour Toxicity - Rainbow Trout: 870 ppb.
Fish Acute 96—Hour Toxicity - Bluegill Sunfish: 460 ppb.
Fish Acute 96-Hour Toxicity - Mysid Shrimp: 0.15 ppm.
Fish Acute 96-Hour Toxicity - Mysid Shrimp: 0.15 mg/L.
Acute Toxicity (96—Hour) Test for Shrimp, Static - Mysid Shrimp:
0.25 mg/L.
Acute Toxicity Test Mollusc, 96—Hour Flowthrough - Eastern Oyster:
187 mg/L.
Acute Toxicity Test for Mollusc, 48—Hour Embryo and Larvae - Eastern
Oyster: 0.079 ppm.
Acute Toxicity Test for Estuarine Fish, Static — Sheepshead Minnow:
1.4 mg/L.
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Acute Toxicity Test for Estuarine Fish, Static - Sheepshead Minnow:
1.76
Freshwater Fish Early Life Study - Fathead Minnow: Maximum allowable
toxic concentration (MATC): 11 to 30 ppb.
Acute Toxicity to Honey Bee: > 50 ug/bee.
Quizalof op ethyl is practically nontoxic to birds, ughly toxic to
freshwater fish, very highly toxic to invertebrates, moderately
toxic to marine fish, very toxic to marine invertebrates, and
relatively nontoxic to honey bees.
Tolerance Assessment :
The nature of the residues in plants and animals is adequately
understood and adequate analytical methods are available for
enforcement purposes.
Tolerances are established for the combined residues of quizalofop
(2-(4-(6-chloroquinoxalin-2-yl oxy)phenoxy]propanoic acid and
quizalof op ethyl (ethyl-2- [ 4-6-chloroquinoxalin—2-yl oxy)phenoxy]
propanoate) all expressed as quizalof op ethyl in or on the raw
agricultural commodity soybeans at 0.05 part per million (ppm).
Tolerances are established for the combined residues of quizalofop,
quizalof op ethyl, and quizalofop methyl (methyl 2- [ 4-(6-chloro—
quinoxalin—2—yl oxy)phenoxy]propanoate), all expressed as quizalof op
ethyl in or on the following raw agricultural commodities.
Commodity
Cattle, fat 0.05
Cattle, meat 0.02
Cattle, mbyp 0.05
Eggs 0.02
Goats, fat 0.05
Goats, meat 0.02
Goats, mbyp 0.05
Hogs, fat 0.05
Hogs, meat 0.02
Hogs, mbyp 0.05
Horses, fat 0.05
Horses, meat 0.02
Horses, mbyp 0.05
Milk 0.01
Milk, fat 0.05
Poultry, fat 0.05
Poultry, meat 0.02
Poultry, mbyp 0.05
Sheep, fat 0.05
Sheep, meat 0.02
Sheep, mbyp 0.05
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Tolerances are established for the combined residues of quizalofop
and quizalofop ethyl, all expressed as quizalofop ethyl in or on
the following processed food/feed commodities.
Commodity
Soybean soapstock 1 .00
Soybean hulls 0.02
Soybean meal 0.50
Soybean flour 0.50
The acceptable daily intake (ADI) based on the 2—year rat feeding/
oncogenicity study (NOEL of 0.9 mg/kg/day) and using a hundredfold
safety factor is calculated to be 0.009 mg/kg/day. The theoretical
maximum residue contribution (TMRC) from these tolerances is calculated
to be 0.000216 mg/kg body weight/day, which occupies approximately
2.4 percent of the ADI. There are no other published tolerances
for this chemical.
4. Summary of Regulatory Position and Rationale
The available data submitted to the Agency provide sufficient
information to support a conditional registration provided that the
following studies are repeated: acute toxicity to freshwater
invertebrates and a confined rotational crop study. Therefore,
the Agency has accepted the use of quizalofop ethyl on soybeans.
5. Summary of Data Gaps Due Dates
Environmental Fate Data 24 Months
Acute Toxicity to Freshwater Invertebrates 12 Months
6. Contact person at EPA :
Robert J. Taylor
Product Manager 25
Fungicide—Herbicide Branch
Registration Division (TS—767C)
Office of Pesticide Programs
Environmental Protection Agency
401 M Street SW.
Washington, DC 20460
Phone: (703) 557—1800
DISCLAIMER: The information in this Pesticide Fact Sheet is a summary
only and may not be used to fulfill data requirements for pesticide
registration and reregistration.
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