Persistence of Fluridone in Small Ponds
1980
Muir, Derek C. G. | Grift, N. P. | Blouw, A. P. | Lockhart, W. L.
Fluridone {1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]-4-[1H]-pyridinone} was applied to three small ponds (5 by 3.5 m²) to give water concentrations of 5,000, 700, and 70 µg/liter, respectively. Water, hydrosoil (0 to 3 and 3 to 6 cm depth), duckweed (Lemna minor), and minnows (Pimephales promelas) were collected for residue analysis over a 70-week period following herbicide application. The half-life of fluridone in the water column (0.5 m depth) ranged from 4 (at 700 µg/liter) to 7 days (70 µg/liter). Upon retreatment of one of the ponds the following year at 100 µg/liter, a half-life of 4 days was observed. Fluridone persisted in hydrosoils with an apparent half-life of 1 year or more at all treatment levels. Retreatment of one of the ponds resulted in a buildup of herbicide residue which dissipated more rapidly (half-life of 20 weeks) than after the first treatment. Bioassays indicated that fluridone residues in hydrosoil from the ponds treated at 700 and 5,000 µg/liter, taken 42 to 70 weeks after treatment, were phytotoxic to duckweed. Fluridone levels in minnows were very low (< 0.02 to 0.14 µg/g) throughout the sampling period with bioconcentration factors ranging from 0 to 64. Fluridone levels in duckweed were proportional to the herbicide concentrations in the pond water with bioconcentration factors ranging from 19 to 85.
Mostrar más [+] Menos [-]Palabras clave de AGROVOC
Información bibliográfica
Este registro bibliográfico ha sido proporcionado por National Agricultural Library