Abstract
Plants, soils and water were collected from Mt. Wakakusa in Nara Prefecture after the aerial application of a fenitrothion formulation for pine budworm control, and the samples were analyzed for fenitrothion and its decomposition products. Fifty percent of the fenitrothion in the applied area degraded in 2-4 days, and 2.5% remained after 144 days. In leaves of Maesa japonica, fenitrothion was detected at 78.3ppm on the day of application, but 99% disappeared within a week. After 144 days, 0.1, 0.01 and 0.001ppm were detected in grasses (mainly Zoysia japanica), and soils of the upper and lower layers, respectively. Fenitrooxon in leaves was 0.1-0.3% of the fenitrothion detected but it disappeared because of rain after 30 days. Aminofenitrothion was found in the amounts of 1-7% of detected fenitrothion in soils for a long time. In natural aquatic systems of this basin, fenitrothion was detected at 38.2ppb immediately after application, but it was reduced rapidly by dilution and then it maintained a low concentration for a long period. After 49 days fenitrothion and 3-methyl-4-nitrophenol were detected at 0.001-0.02ppb and 0.001-0.07ppb, respectively. The effusion of fenitrothion by aquatic systems from the applied area was estimated at 0.7% (1.0% in consideration of 3-methyl-4-nitrophenol) for 49 days.
