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The information in this profile may be out-of-date. It was last revised in 1996. EXTOXNET no longer updates this information, but it may be useful as a reference or resource.

Please visit the National Pesticide Information Center (NPIC) to find updated pesticide fact sheets. If you don't find a fact sheet related to your question, feel free to call 1-800-858-7378. NPIC is open five days a week from 8:00am to 12:00pm Pacific Time.

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E X T O X N E T

Extension Toxicology Network

Pesticide Information Profiles

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Oregon State University, the University of Idaho, and the University of California at Davis and the Institute for Environmental Toxicology, Michigan State University. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.

EXTOXNET primary files maintained and archived at Oregon State University

Revised 9/95.

HALOXYFOP

REGULATORY STATUS: Registration is pending for use of haloxyfop in the United States (41).

INTRODUCTION: Haloxyfop is in the pyridine chemical family (40). It is produced in two forms, haloxyfop-methyl and haloxyfop-ethoxyethyl. Both are used as pre- and postemergence selective herbicides. They control annual and perennial grasses in sugar beet, oilseed, potatoes, leaf vegetables, onions, sunflowers, strawberries, and other crops. Haloxyfop-ethoxyethyl and haloxyfop-methyl are absorbed into the plant and inhibit growth (6). The EPA classifies haloxyfop as toxicity class II-moderately toxic. All products containing haloxyfop bear the Signal Word "Warning." It is available as an emulsifiable concentrate (41).

TOXICOLOGICAL EFFECTS

• Acute Toxicity: The oral LD50, the dose of haloxyfop-methyl that kills half of the study animals, is 393 mg/kg for rats. The LD50 is greater than 5,000 mg/kg for rabbits whose skin is exposed to haloxyfop-methyl (8). Haloxyfop-ethoxyethyl has an oral LD50 of 518-531 mg/kg for rats. The dermal LD50 is greater than 2000 mg/kg for rats and greater than 5,000 mg/kg for rabbits. Both haloxyfop forms are non-irritating to skin and do not cause skin sensitization. They are mild eye irritants (6). The symptoms of toxicity in rats are reduced food intake and reduced food consumption. They may also cause liver and kidney damage (8).
• Chronic Toxicity: No Information Available.
• Reproductive Effects: In rats, oral doses of 10 and 50 mg/kg/day of haloxyfop-ethoxyethyl from days 6 to 16 of pregnancy reduced the number of live offspring per litter and caused vaginal bleeding in the mother (42).
• Teratogenic Effects: Oral doses of 50 mg/kg/day of haloxyfop-ethoxyethyl in rats between days 6 and 16 of pregnancy caused developmental abnormalities in the offspring's urogenital system and death to the fetus (42). Oral doses of 7.5 mg/kg/day of haloxyfop-methyl given to rats from days 6 to 15 of pregnancy caused delayed bone formation in the offspring (31).
• Mutagentic Effects: No information is currently available.
• Carcinogenic Effects: Studies show that 0.1 mg/kg/day of haloxyfop-methyl for two years, the highest dose tested, does not cause cancer in rats. Similarly, 0.6 mg/kg/day for two years, the highest dose tested, is not carcinogenic to mice (31).
• Organ Toxicity: Doses of 100 mg/kg/day of haloxyfop-methyl caused kidney damage in adult rats (8). Doses of 0.6 mg/kg/day for 2 years in mice caused reduced body weight gains and increased liver weights in mice. In dogs, 5 mg/kg/day causes a significant decrease in serum cholesterol, as well as a decrease in thyroid weight (31).
• Fate in Humans and Animals: In rats, haloxyfop-ethoxyethyl undergoes metabolism to haloxyfop which is excreted in feces and urine (6).

ECOLOGICAL EFFECTS

• Effects on Birds: Haloxyfop-methyl and haloxyfop-ethoxyethyl are practically non-toxic to birds. The oral LD50 is greater than 2,150 mg/kg for mallard ducks. The dietary LC50 (8 day) is greater than 5,620 mg/kg for bobwhite quail (6,40).
• Effects on Aquatic Organisms: Haloxyfop-methyl is practically non-toxic to fish. The LC50, the concentration in water at which half of the test animals died, ranges from 96 to greater than 1000 mg/kg (40). Haloxyfop-ethoxyethyl is moderately to highly toxic to fish. The LC50 (96 hour) is 0.54 mg/l for fathead minnows, 0.28 mg/l for bluegill sunfish, and 1.8 mg/l for rainbow trout. The LC50 (48 hours) for Daphnia is 4.64 mg/l (6).
• Effects on Other Animals (Nontarget species): Haloxyfop is not toxic to bees. The contact and oral LD50 (48 hours) is 100 micrograms haloxyfop/bee (6).

ENVIRONMENTAL FATE

• Breakdown of Chemical in Soil and Groundwater: Haloxyfop-ethoxyethyl is converted to haloxyfop in soil. The half-life of haloxyfop-ethoxyethyl, the amount of time needed to reduce its concentration by half, is greater than one day on silty clay loam at 20 degrees C. The half-life of haloxyfop in soil is 55-100 days depending on the soil (6). Leaching is moderate (42).
• Breakdown of Chemical in Surface Water: The half-life of haloxyfop in water is 33 days for haloxyfop at pH 5, 5 days at pH 7, and a few hours at pH 9 (6).
• Breakdown of Chemical in Vegetation: No information is currently available.

PHYSICAL PROPERTIES AND GUIDELINES

Haloxyfop (acid) is a white crystal with an offensive odor. Haloxyfop-ethoxyethyl is a colorless crystal which is hydrolyzed to haloxyfop under acidic and alkaline conditions. The rate of hydrolysis increases with temperature (6). Haloxyfop-methyl is an amber to straw yellow solid with a mild aromatic odor. It is stable to UV light and in high temperatures. There is no decomposition after 88 hours at 200 degrees C.

Physical Properties:

• Appearance: colorless crystals
• Chemical Name: (Haloxyfop-ethoxyethyl - 2-(4-((3-chloro-5-trifluoro methyl)-2-pyridinyl), 2-(4-(3-chloro-5-(trifluoromethyl)-2-pyridinyl)oxy) phenoxy-, methyl esteroxy)phenoxy)-2-ethoxyethyl ester)
• CAS Number: (Haloxyfop-ethoxyethyl - 87237-48-7), 69806-40-2
• Molecular Weight: 361.7 (acid) 433.81(haloxyfop ethoxyethyl) 375.73(haloxyfop-methyl)
• Water Solubility: 0.5 mg/l (haloxyfop-ethoxyethyl)43.3 mg/l(acid) 9.3 mg/l (haloxyfop-methyl)(7)
• Solubility in Other Solvents: xylene: 125g/100 ml (haloxyfop-ethoxyethyl) 127g/100 ml (haloxyfop-methyl) 7.4g/100 ml(acid) acetone: >100g/100 ml (acid, haloxyfop ethoxyethyl, haloxyfop-methyl) toluene: >100g/100 ml (ethoxyethyl) 11.8g/100 ml (acid)
• Melting Point: 107-108 degrees C (acid) 56-58 degrees C (haloxyfop-ethoxyethyl) (6) 55-57 degrees C (haloxyfop-methyl)
• Vapor Pressure: <1.3 x 10 to the minus 7 mm Hg at 25 degrees C (acid) 3.4 x 10 to the minus 6mm Hg at 25 degrees C (haloxyfop ethoxyethyl) 6.5 x 10 to the minus 7 mm Hg at 25 degrees C (haloxyfop-methyl)
• Partition Coefficient: Not Available
• Adsorption Coefficient: (haloxyfop-ethoxyethyl) 29,500 (6)

Exposure Guidelines:

All guidelines given are for haloxyfop-methyl.

• ADI: Not Available
• MCL: Not Available
• RfD: 5.0 x 10 -5 mg\kg\day (kidney effects)(8)
• PEL: Not Available
• HA: Not Available
• TLV: Not Available
• NOEL: 0.005 mg/kg/day (8)
• LEL: 0.05 mg/kg/day (reduced fertility) (8)

BASIC MANUFACTURER:

DowElanco
Crops Division
9002 Purdue Road
Indianapolis, IN 46268-1189

• Telephone: 800-258-3033
• Emergency: 517-636-4400

REFERENCES

References for the information in this PIP can be found in Reference List Number 7