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EXTOXNET PIP-GLYPHOSATE *4w http://extoxnet.orst.ediVpips/glyphosa.htrn 1./ mg/L in harlequin, and 86 mg/L in rainbow trout [58]. The reported 96-hour LC50 values for other aquatic species include greater than 10 mg/L in Atlantic oysters, 934 mg/L in fiddler crab, and 281 mg/L in shrimp [58]. The 48-hour LC50 for glyphosate in Daphnia(water flea), an important food source for freshwater fish, is 780 mg/L [58]. Some formulations may be more toxic to fish and aquatic species due to differences in toxicity between the salts and the parent acid or to surfactants used in the formulation [58,96]. There is a very low potential for the compound to build up in the tissues of aquatic invertebrates or other aquatic organisms [96]. • Effects on other organisms: Glyphosate is nontoxic to honeybees [1,58]. Its oral and dermal LD50 is greater than 0.1 mg/bee [98]. The reported contact LC50 values for earthworms in soil are greater than 5000 ppm for both the glyphosate trimethylsulfonium salt and Roundup [58]. Environmental Fate: • Breakdown in soil and groundwater: Glyphosate is moderately persistent in soil, with an estimated average half-life of 47 days [58,11]. Reported field half-lives range from 1 to 174 days [11]. It is strongly adsorbed to most soils, even those with lower organic and clay content [11,58]. Thus, even though it is highly soluble in water, field and laboratory studies show it does not leach appreciably, and has low potential for runoff(except as adsorbed to colloidal matter) [3,11]. One estimate indicated that less than 2% of the applied chemical is lost to runoff[99]. Microbes are primarily responsible for the breakdown of the product, and volatilization or photodegradation losses will be negligible [58]. • Breakdown in water: In water, glyphosate is strongly adsorbed to suspended organic and mineral matter and is broken down primarily by microorganisms [6]. Its half-life in pond water ranges from 12 days to 10 weeks [97]. • Breakdown in vegetation: Glyphosate may be translocated throughout the plant, including to the roots. It is extensively metabolized by some plants, while remaining intact in others [1]. Physical Properties: • Appearance: Glyphosate is a colorless crystal at room temperature [1]. • Chemical Name: N-(phosphonomethyl) glycine [1] • CAS Number: 1071-83-6 • Molecular Weight: 169.08 • Water Solubility: 12,000 mg/L @ 25 C [1] • Solubility in Other Solvents: i.s. in common organics (e.g., acetone, ethanol, and xylene) [1] • Melting Point: 200 C [1] • Vapor Pressure: negligible [1] • Partition Coefficient: -3.2218 - -2.7696 [58] • Adsorption Coefficient: 24,000 (estimated) [11] Exposure Guidelines: • ADI: 0.3 mg/kg/day [12] • MCL: Not Available • RfD: 0.1 mg/kg/day [13] • PEL: Not Available • HA: 0.7 mg/L(lifetime) [98] • TLV: Not Available 3 of 4 2/20/2008 2:07 PM