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The information in this profile may be out-of-date.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 June 1996

Sethoxydim

Trade and Other Names: Trade names include Aljaden, Alloxol S, BAS 9052H, Checkmate, Expand, Fervinal, Grasidim, Nabu, NP-55, Poast, Tritex-Extra, and Vantage.

Regulatory Status: Sethoxydim is a General Use Pesticide (GUP). It is in EPA toxicity class III - slightly toxic. Products containing sethoxydim bear the Signal Word CAUTION on the label.

Chemical Class: Not Available

Introduction: Sethoxydim is a selective post-emergence herbicide used to control annual and perennial grass weeds in broad-leaved vegetable, fruit, field, and ornamental crops. It also has indoor uses. It is available in emulsifiable concentrate formulations.

Formulation: It is available in emulsifiable concentrate formulations.

Toxicological Effects:

• Acute toxicity: Sethoxydim is slightly toxic by ingestion, and practically nontoxic by dermal absorption [58]. It causes skin and eye irritation. Inhalation of dusts or vapors can cause irritation of the throat and nose [58]. Other symptoms of poisoning include incoordination, sedation, tears, salivation, tremors, blood in the urine, and diarrhea [58]. Sethoxydim does not cause allergic skin reactions [3]. The oral LD50 for sethoxydim in rats is 2600 to 3100 mg/kg [1,58]. The dermal LD50 in rats is greater than 5000 mg/kg (1,58) and the 4-hour inhalation LC50 for sethoxydim in rats is greater than 6.3 mg/L [1].
• Chronic toxicity: Long-term contact with sethoxydim can cause redness and swelling of the eyes or skin [8]. No adverse effects were observed in mice given 2, 6, or 18 mg/kg/day for 2 years [58,126]. In a 1-year dog feeding study, doses above 8.86 mg/kg/day in males and 9.41 mg/kg/day in females produced anemia [13,58].
• Reproductive effects: When pregnant rabbits were fed 40, 160, or 480 mg/kg/day, decreased litter size, low fetal weights, severe maternal weight loss, increased fetal resorptions, spontaneous abortions, and maternal deaths occurred at the 480 mg/kg level [126]. Based on this study, reproductive effects are unlikely in humans at expected exposure levels.
• Teratogenic effects: No developmental effects were observed in offspring of rats at maternal dose levels of 40, 100, or 250 mg/kg/day [126]. Increased numbers of skeletal and visceral abnormalities occurred in rabbits at doses of 480 mg/kg/day [13]. These data suggest that sethoxydim is unlikely to be teratogenic in humans at expected exposure levels.
• Mutagenic effects: Several tests of the mutagenicity of sethoxydim indicate that it is not mutagenic [126].
• Carcinogenic effects: No carcinogenic effects were observed at any dose level when mice were fed 6, 18, 54, or 162 mg/kg/day for 2 years [13,126]. This suggests that sethoxydim is not carcinogenic.
• Organ toxicity: Liver and bone marrow effects and increased thyroid weight have been reported in dogs [13].

• Fate in humans and animals: Single doses of the compound fed to rats were nearly completely eliminated (98.6%) through urine and feces within 48 hours [1].

Ecological Effects:

• Effects on birds: Sethoxydim is practically nontoxic to birds. The acute oral LD50 for sethoxydim in mallard ducks is greater than 2510 mg/kg [58], and in Japanese quail is greater than 5000 mg/kg [1]. Its dietary LC50 in mallards and bobwhite quail is greater than 5620 ppm [58,127].
• Effects on aquatic organisms: Sethoxydim is moderately to slightly toxic to aquatic species. A 3-hour LC50 of 1.5 mg/L is reported in Daphnia [1]. In fish, 96-hour LC50 valuees range from 1.6 mg/L in carp [58], to 32 mg/L in rainbow trout, and 100 mg/L in bluegill sunfish [58].
• Effects on other organisms: Sethoxydim has low toxicity to wildlife [8]. It is nontoxic to bees [1].

Environmental Fate:

• Breakdown in soil and groundwater: Sethoxydim is of low soil persistence. Reported field half-lives are 5 to 25 days [58,11]. It has a weak tendency to adsorb to soil particles [58]. Laboratory leaching tests have suggested that sethoxydim could leach in soil. However, in field tests, sethoxydim did not leach below the top 4 inches of soil, and it did not persist [127]. On soil, photodegradation of sethoxydim takes less than 4 hours [58]. The product Poast photodegrades on soil surfaces with a half-life of approximately 3.7 hours [127]. Disappearance of sethoxydim is primarily due to action by soil microbes.
• Breakdown in water: In water, photodegradation of sethoxydim takes less than 1 hour [8]. The product Poast is fairly stable to the chemical action of water (hydrolysis), with a half-life of about 40 days in a neutral solution at 25 C [127].
• Breakdown in vegetation: Sethoxydim is absorbed rapidly by roots and foliage, and moves both upward and downward in plants from the point of absorption [58]. Sethoxydim is rapidly detoxified in most tolerant plants [58]. The product Poast accumulates in the tissues of crops planted in fields after harvest of treated crops. Measured residues were all below 0.066 ppm [11].

Physical Properties:

• Appearance: Sethoxydim is an amber-colored, oily, odorless liquid [1].
• Chemical Name: (+/-) 2 [1(ethoxyimino) butyl]-5-[2-(ethylthio) propyl]-3-hydroxy-2-cyclohexen-1-one [1]
• CAS Number: 74051-80-2
• Molecular Weight: 327.50
• Water Solubility: 4700 mg/L @ pH 7 and 20 C [1]
• Solubility in Other Solvents: v.s. in methanol, hexane, and acetone [1]
• Melting Point: Not Available
• Vapor Pressure: <0.1 mPa @ 20 C [1]
• Partition Coefficient: 1.6542 @ pH 7 [58]
• Adsorption Coefficient: 100 (estimated) [11]

Exposure Guidelines:

• ADI: Not Available
• MCL: Not Available
• RfD: 0.09 mg/kg/day [13]
• PEL: Not Available
• HA: Not Available
• TLV: Not Available

Basic Manufacturer:

BASF Corporation
Agricultural Products Group
P.O. Box 13528
Research Triangle Park, NC 27709-3528

• Phone: 800--669-2273
• Emergency: 800-832-4357
  

References:

References for the information in this PIP can be found in Reference List Number 10

DISCLAIMER: The information in this profile does not in any way replace or supersede the information on the pesticide product labeling or other regulatory requirements. Please refer to the pesticide product labeling.