E X T O X N E T
Extension Toxicology Network
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University of California at Davis. Major support and funding was provided
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Pesticide
Information
Profile
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Oxyfluorfen
Publication Date: 9/93
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TRADE OR OTHER NAMES
Some trade names include Goal, Koltar and RH-2915
REGULATORY STATUS
Products containing oxyfluorfen must bear the signal word "Warning" on
the label (1).
INTRODUCTION
Oxyfluorfen is a selective pre and postemergent herbicide used to control
certain annual broadleaf and grassy weeds in vegetables, fruit, cotton, es]
ornamentals and on non-crop areas. It is a contact herbicide and light is
required for it to affect target plants (4). It is available in emulsifiable
concentrate and granular formulations (1).
TOXICOLOGICAL EFFECTS
ACUTE TOXICITY
Oxyfluorfen is a moderately toxic by ingestion and slightly toxic by
dermal absorption (2). Vapors may cause irritation of the nose, throat, skin
and eyes, and other forms may cause irritation to skin and eyes (2).
The oral LD50 for technical oxyfluorfen in rats is 5,000 mg/kg and >
5,000 mg/kg in dogs (1, 2). The dermal LD50 on rabbits is > 10,000 mg/kg (1).
CHRONIC TOXICITY
Long-term exposure to oxyfluorfen may cause the same symptoms as short-term
exposure (2). Effects on the liver have been observed in long-term
feeding studies with rats, mice and dogs (2). In a 2-year feeding study with
dogs, the NOEL was 100 ppm (2.5 mg/kg/day) (5).
Reproductive Effects
In a developmental study with rats given doses of 10, 100 or 1,000
mg/kg/day by gavage, lower implantation, higher resorption, and lower fetal
survival was seen at the 1,000 mg/kg level. Toxic effects on the mothers were
also seen at this dose (5).
The NOEL in a 3-generation reproduction study with rats was 10 ppm (0.5
mg/kg/day). At 100 ppm (5 mg/kg/day), there were decreased survival of
fetuses and decreased maternal and fetal weights (5).
Teratogenic Effects
In a developmental study with rabbits, 30 mg/kg/day, the highest dose
tested, produced an increase in fused sternal bones in the fetuses as well as
toxic effects on the mothers. The NOEL was 10 mg/kg/day (5).
Mutagenic Effects
Mutagenicity tests have produced mixed results. Tests on rats, mice and
on bacterial cell cultures and unscheduled DNA synthesis tests have been
negative, while other tests on mice and bacterial cell cultures have been
positive (5).
Carcinogenic Effects
In a 20-month study with mice fed 2, 20 or 200 ppm, doses above 2 ppm
produced benign and malignant liver tumors in male mice. No tumors were
formed in female mice (5). No carcinogenic effects were observed in a 2-year
study with rats fed doses as high as 40 mg/kg and increased to 80 mg/kg after
57 weeks (5). EPA has classified oxyfluorfen as a possible human carcinogen
because it caused tumor formation in one sex of one test species and because
it was mutagenic in bacterial and mouse cell cultures (5).
Organ Toxicity
Effects on the liver have been observed in long term feeding studies of
rats, mice and dogs (2).
Fate in Humans and Animals
Because oxyfluorfen is highly hydrophobic, it is expected to concentrate
in the fatty tissues of animals (7).
ECOLOGICAL EFFECTS
Effects on Birds
The oral LD50 for technical oxyfluorfen in bobwhite quail is > 2,000
mg/kg and considered practically non-toxic. The dietary LC50 for oxyfluorfen
in bobwhite quail is 390 ppm, and in mallard ducks is 4,000 ppm (7).
Dietary concentrations as high as 100 ppm had no effect on reproduction
in mallards or bobwhite quail (7).
Effects on Aquatic Organisms
Oxyfluorfen is highly toxic to aquatic invertebrates, freshwater clams,
oysters, aquatic plants and fish (4). Its acute LC50 in bluegill sunfish is
200 ppb, 410 ppb in rainbow trout, 400 ppb in channel catfish, 150 ppb in
fathead minnow, 32 ppb in grass shrimp, and 32 ppb in oysters (7). Its 96-
hour LC50 in freshwater clams is 10 ppm. The 96-hour LC50 for the product
Goal 2E in Daphnia magna, a small freshwater crustacean, is 1.5 ppm (7).
Oxyfluorfen accumulated up to 13 ppm in bluegill sunfish exposed to 10
ppb for 40 days. This represents a bioconcentration factor (BCF) of 1,300.
The BCF in channel catfish was 700 to 5,000 in one 30-day study (7).
Effects on Other Animals (Nontarget species)
No information was found.
ENVIRONMENTAL FATE
Breakdown of Chemical in Soil and Groundwater
Oxyfluorfen has a strong tendency to adsorb to soil particles and is
nearly insoluble in water (3). Once oxyfluorfen is adsorbed to soil
particles, it is not readily removed (4). It is therefore unlikely to leach
downward or to contaminate groundwater. In aged sandy loam, 82% of applied
oxyfluorfen remained in the top 2 inches of soil. Oxyfluorfen did not leach
below 4 inches in any soil except sand (6).
In soils, oxyfluorfen is not subject to microbial degradation (4, 7), and
is not subject to hydrolysis at pH 5, 7 or 9 (6). It is therefore highly
resistant to degradation in the soil environment (7). Decomposition by light
occurs slowly, with 15% of the oxyfluorfen applied to a soil surface degrading
within 28 days (7). In laboratory studies, its soil half-life was 6 months
(7). Its soil half-life in field studies is 30 to 70 days, with much of the
loss probably due to volatilization (3, 4, 7).
Breakdown of Chemical in Surface Water
In water, oxyfluorfen is rapidly decomposed by light (4). Because
oxyfluorfen is nearly insoluble in water and has a tendency to adsorb to soil,
it is unlikely to remain in water. It will instead adsorb to suspended
particles or sediments (7).
Breakdown of Chemical in Vegetation
There is very little movement of oxyfluorfen within treated plants. It
is not readily metabolized by plants, but since it is not readily taken up by
roots, residues in plants are very low (4). In crop rotation studies,
residues of oxyfluorfen were found in small grains, but not in root or
vegetable crops grown on previously treated fields (6). When carrots,
lettuce, oats and cotton were planted in plots treated with 0.25 to 0.5 pounds
per acre of radio-labeled oxyfluorfen on year prior to planting, low levels of
residues were found in carrots and oats, but not in cotton or lettuce (7).
PHYSICAL PROPERTIES AND GUIDELINES
Oxyfluorfen is a white to orange or red-brown crystalline solid with a
smoke-like odor (1, 2, 4). It may decompose if exposed to UV light (2).
Oxyfluorfen is stable under normal temperatures and pressures, but poses
a slight fire hazard if exposed to heat or flame, and a fire and explosion
hazard in the presence of strong oxidizers. It may burn but will not readily
ignite. It may form flammable or explosive dust-air mixtures. Avoid contact
with strong oxidizers, excessive heat, sparks or open flame. Thermal
decomposition may release highly toxic fumes of fluorides and chlorides and
toxic oxides of nitrogen and carbon. Workers handling oxyfluorfen should wear
goggles to prevent eye contact with this chemical and protective clothing to
prevent prolonged skin contact (2).
Exposure Guidelines:
No occupational exposure limits have been established for oxyfluorfen by
OSHA, NIOSH or ACGIH (2).
| Rohm and Haas recommended TWA: | 0.2 mg/m3 (2) |
| Rohm and Haas recommended STEL: | 1.6 mg/m3 (2) |
Physical Properties:
| CAS #: | 42874-03-3 |
| Chemical name: | 2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluromethyl)benzene |
| Chemical Class/Use: | diphenyl ether herbicide |
| Specific gravity: | 1.35 at 73 degrees C (2) |
| H20 solubility: | nearly insoluble (1); 0.1 ppm (2). |
| Solubility in other solvents: | readily soluble in most organic solvents (1) |
| Melting point: | 181-183 degrees F (83-84 degrees C) (2) |
| Boiling point: | > 464 degrees F (> 240 degrees C), decomposes (2), 358.7 (7). |
| Decomposition temperature: | > 240 degrees C (4) |
| Flashpoint: | > 200 degrees F (> 93 degres C) (2) |
| Vapor pressure: | negligible at 25 degrees C (2); 2 x 10 to the minus 6 power mm Hg at 25 degrees C (4). |
| Koc: | 100,000 (3, 6) |
BASIC MANUFACTURER
Rohm and Haas Co.
Agricultural Chemicals
Independence Mall West
Philadelphia, PA 19105
Review by Basic Manufacturer:
Comments solicited: April, 1993
Comments received: May, 1993
REFERENCES
Meister, R.T. (ed.). 1992. Farm Chemicals Handbook '92. Meister
Publishing Company, Willoughby, OH.
Occupational Health Services, Inc. 1992 (Nov. 17). MSDS for
Oxyfluorfen. OHS Inc., Secaucus, NJ.
U. S. Department of Agriculture, Soil Conservation Service. 1990
(Nov.). SCS/ARS/CES Pesticide Properties Database: Version 2.0
(Summary). USDA - Soil Conservation Service, Syracuse, NY.
WSSA Herbicide Handbook Committee. 1989. Herbicide Handbook of the
Weed Science Society of America, 6th Ed. WSSA, Champaign, IL.
U.S. Environmental Protection Agency. May 27, 1992. Pesticide
tolerances for oxyfluorfen. Federal Register 57 (102): 22202-3.
US Environmental Protection Agency. March 13, 1992. Pesticide
Environmental Fate One Line Summary: Oxyfluorfen. Environmental Fate and
Effects Division, US EPA, Washington, DC.
US Environmental Protection Agency. July 20, 1984. EEB Chemical
Profile: Oxyfluorfen. US EPA, Washington, DC.
Disclaimer: Please read
the pesticide label prior to use. The information contained at this web
site is not a substitute for a pesticide label. Trade names used herein
are for convenience only; no endorsement of products is intended, nor is
criticism of unnamed products implied. Most of this information is historical
in nature and may no longer be applicable.
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