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I 5 mg/kg/day,there was decreased survival of fetuses and decreased maternal and fetal weights [108]. It does not appear likely that oxyfluorfen will cause reproductive effects in humans at likely levels of exposure. • 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 [108]. These data suggest oxyflurofen may have teratogenic effects, but only at very high doses. • Mutagenic effects: Mutagenicity tests on rats, mice and on bacterial cell cultures have produced mixed results. However, unscheduled DNA synthesis assays have been negative [58,108]. Due to the conflicting results, it is not possible to determine the mutagenic potential of oxyfluorfen. • Carcinogenic effects: In a 20-month study with mice fed 0.3, 3, or 30 mg/kg/day, doses at and above 3 mg/kg/day produced non-significant increases in both benign and malignant liver tumors in male mice [58,108]. No increased tumor formation was seen in female mice at any dose [58,108]. No carcinogenic effects were observed in a 23-year study with rats fed doses 2 mg/kg/day, nor in dogs at doses of 3 mg/kg/day [58,108]. These data suggest that oxyfluorfen is not carcinogenic. • Organ toxicity: The liver appears to be the'main target organ, based on long-term feeding 4 studies. • Fate in humans and animals: Because oxyfluorfen is highly hydrophobic, it may have the potential to bioconcentrate in animal fatty tissues [108]. Ecological Effects: Effects on birds: Oxyfluorfen is practically nontoxic to birds; the reported oral LD50 values are greater than 2200 mg/kg in bobwhite quail, and greater than 4000 mg/kg in mallard duck [108]. The dietary 8-day dietary LC50 values are greater than 5000 ppm in bobwhite quail, and 4000 ppm in mallard ducks [58,109]. Dietary concentrations as high as 100 ppm had no effect on reproduction in mallards or bobwhite quail [109]. • Effects on aquatic organisms: Oxyfluorfen is highly toxic to aquatic invertebrates, freshwater clams, oysters, aquatic plants, and fish. The reported 96-hour LC50 values are 200 ug/L in bluegill sunfish, 410 ug/L in rainbow trout, 400 ug/L in channel catfish, 150 ug/L in fathead minnow,and 32 ug/L in grass shrimp and oysters [58,109]. Its 96-hour LC50 in freshwater clams is 10 ug/L. The 96-hour LC50 for the product Goal 2E in Daphnia magna, a small freshwater crustacean, is 1500 ug/L [58,109]. Oxyfluorfen accumulated up to 13 mg/kg (13,000 ug/kg) in bluegill sunfish exposed to 10 ug/L for 40 days [108]. This represents a bioconcentration factor (BCF) of 1300. The BCF in channel catfish was 700 to 5000 in one 30-day study [109]. These results indicate a low to moderate potential for bioaccumulation in aquatic species. • Effects on other organisms: Oxyfluorfen is nontoxic to honeybees, with a reported oral LC50 of greater than 10,000 ppm [58]. Environmental Fate. . • Breakdown in soil and groundwater: Oxyfluorfen is moderately persistent in most soil environments, with a representative field half-life of about 30 to 40 days 58 11 p y [ 0]. Oxyfluorfen is not subject to microbial degradation or hydrolysis [58,11]. The main mechanism of degradation in soils may be photode gradation and evaporation/codistiliation in moist soils [5 8,110]. In laboratory studies, its soil half-life was 6 months, indicating very low rates of microbial degradation [58,11]. Oxyfluorfen is very well-sorbed to most soils [11]. Soil binding is highest in soils with high organic matter and clay content [58,11]. Once oxyfluorfen is adsorbed