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EXTOXNET PIP - OXYFLUORFEN Page 2 of 3
<br /> decreased implantation, increased resorption, and lower fetal survival was seen at the 1000 mg/kg level. Toxic
<br /> effects on the mothers were also seen at this dose [108]. At 5 mg/kg/day, there was decreased survival of fetuses
<br /> and decreased maternal and fetal weights [108]. It does not appear likely that oxyfluorfen will cause reproductive
<br /> effects in humans at likely levels of exposure.
<br /> • Teratogenic effects: In a developmental study with rabbits, 30 mg/kg/day, the highest dose tested,produced an
<br /> increase in fused sternal bones in the fetuses as well as toxic effects on the mothers [108]. These data suggest
<br /> oxyflurofen may have teratogenic effects, but only at very high doses.
<br /> • Mutagenic effects: Mutagenicity tests on rats, mice and on bacterial cell cultures have produced mixed results.
<br /> However, unscheduled DNA synthesis assays have been negative [58,108]. Due to the conflicting results, it is not
<br /> possible to determine the mutagenic potential of oxyfluorfen.
<br /> • 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
<br /> produced non-significant increases in both benign and malignant liver tumors in male mice [58,108]. No increased
<br /> tumor formation was seen in female mice at any dose [58,108]. No carcinogenic effects were observed in a 23-year
<br /> 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
<br /> oxyfluorfen is not carcinogenic.
<br /> • Organ toxicity: The liver appears to be the main target organ, based on long-term feeding studies.
<br /> • Fate in humans and animals: Because oxyfluorfen is highly hydrophobic, it may have the potential to
<br /> bioconcentrate in animal fatty tissues [108].
<br /> Ecological Effects:
<br /> • Effects on birds: Oxyfluorfen is practically nontoxic to birds; the reported oral LD50 values are greater than 2200
<br /> mg/kg in bobwhite quail, and greater than 4000 mg/kg in mallard duck [108]. The dietary 8-day dietary LC50
<br /> values are greater than 5000 ppm in bobwhite quail, and 4000 ppm in mallard ducks [58,109]. Dietary
<br /> concentrations as high as 100 ppm had no effect on reproduction in mallards or bobwhite quail [109].
<br /> • Effects on aquatic organisms: Oxyfluorfen is highly toxic to aquatic invertebrates, freshwater clams, oysters,
<br /> aquatic plants, and fish. The reported 96-hour LC50 values are 200 ug/L in bluegill sunfish,410 ug/L in rainbow
<br /> trout, 400 ug/L in channel catfish, 150 ug/L in fathead minnow, and 32 ug/L in grass shrimp and oysters [58,109].
<br /> Its 96-hour LC50 in freshwater clams is 10 ug/L. The 96-hour LC50 for the product Goal 2E in Daphnia magna, a
<br /> small freshwater crustacean, is 1500 ug/L [58,109]. Oxyfluorfen accumulated up to 13 mg/kg (13,000 ug/kg) in
<br /> bluegill sunfish exposed to 10 ug/L for 40 days [108]. This represents a bioconcentration factor(BCF) of 1300. The
<br /> BCF in channel catfish was 700 to 5000 in one 30-day study [109]. These results indicate a low to moderate
<br /> potential for bioaccumulation in aquatic species.
<br /> • Effects on other organisms: Oxyfluorfen is nontoxic to honeybees,with a reported oral LC50 of greater than
<br /> 10,000 ppm [58].
<br /> Environmental Fate:
<br /> • Breakdown in soil and groundwater: Oxyfluorfen is moderately persistent in most soil environments, with a
<br /> representative field half-life of about 30 to 40 days [58,110]. Oxyfluorfen is not subject to microbial degradation or
<br /> hydrolysis [58,11]. The main mechanism of degradation in soils may be photodegradation and
<br /> evaporation/codistillation in moist soils [58,110]. In laboratory studies, its soil half-life was 6 months, indicating
<br /> very low rates of microbial degradation [58,11]. Oxyfluorfen is very well-sorbed to most soils [11]. Soil binding is
<br /> highest in soils with high organic matter and clay content [58,11]. Once oxyfluorfen is adsorbed to soil particles, it
<br /> is not readily removed [58]. It is practically insoluble in water, and therefore is unlikely to be appreciably mobile in
<br /> most instances, unless the sorptive capacity of the soil is exceeded. Oxyfluorfen did not leach below 4 inches in any
<br /> soil except sand [11].
<br /> • Breakdown in water: In water, oxyfluorfen is rapidly decomposed by light [3]. Because oxyfluorfen is nearly
<br /> insoluble in water and has a tendency to adsorb to soil, it will be sorbed to suspended particles or sediments
<br /> http://extoxnet.orst.edu/pips/oxyfluor.htm 3/13/2006
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