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EXTOXNET PIP - SETHOXYDIM Page 2 • 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 ftw 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 [I I]. -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: