The accumulation and dissipation patterns of the aquatic herbicide fluridone, l-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4( 1H)-pyridinone, and its major degradation products have been determined in 40 pond and lake experiments in the United States, Panama, and Canada. The average bioconcentration factor for the total residue of fluridone plus a single major metabolite, l-methyl-3-(4-hydroxyphenyl)-5-[3-(trifluoromethyl)phenyl]-4(1H)-pyridinone, in several fish species was 1.33, 7.38, and 6.08 in edible tissue, inedible tissue, and whole body, respectively. Fluridone dissipated with an average half-life of 20 days in pond water and 3 months in pond hydrosoil. The treatment of small areas (0.8-4.0 ha) of large lakes resulted in more rapid dissipation due to dispersal of fluridone into the surrounding untreated water. Little or no carry-over of residues occurred prior to annual retreatments of the ponds. Mathematical models were evaluated for relating the half-life of fluridone in pond water to physical and chemical properties of the water. Fluridone, l-methyl-3-phenyl-5-[3-(trifluoromethyl)-phenyl]-4(1H)-pyridinone (I), is the active ingredient in 0 0 0 0

The dissipation of the aquatic herbicide fluridone, l-methyl-3-phenyl-5-[3-trifluoromethyl)phenyl]-4(lJ/)-pyridinone, has been determined in experiments conducted in small ponds at three different geographic regions in the United States and in Gatun Lake of the Panama Canal. Fluridone dissipated rapidly from the water, with a half-life averaging 5 days. The dissipation was due in part to deposition on hydrosoil and uptake by aquatic plants, although evidence is presented to suggest photolysis as a

A gas-liquid chromatographic (GLC) method is described for determining residues of the aquatic herbicide fluridone (l-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4(lH)-pyridinone) and its major metabolite (l-methyl-3-(4-hydroxypherayl)-5-[3-(trifluoromethyl)phenyl]-4(lH)-pyridinone) in fish. Both compounds are extracted from fish tissue with methanol, and the extracts are subjected to acidic hydrolysis to release conjugated forms of fluridone and the metabolite. After purification by liquid-liquid partitioning, sample extracts are reacted with methyl iodide to methylate the metabolite, and then both fluridone and the metabolite are brominated with phosphorus tribromide. After purification by Florisil column chromatography, the derivatives are separated and measured by electron capture GLC. The method is capable of determining approximately 0.01 ppm of both compounds in fish, and recoveries have averaged 84±14.7% for fluridone and 83±13.4% far the metabolite.