The concentration and the loading rate of pesticides were investigated in a streamlet flowing through a golf links. The water samples were collected once a week for a year and during three storm runoff events (23.9-188mm). From the 50 weekly observations, the herbicides Simazin, Oxadiazon and Atrazine, and the insecticide Diazinon were detected. Atrazine, however, was not listed on the application record obtained from the golf links. The net average concentrations of pesticides discharged from the golf links were 0.92, 0.61, 0.28 and 0.04 µg/l, respectively, and their detection rates were 98, 60, 62 and 92%, respectively. Fenitrothion and Fenthion. though listed on the applications, were not detected. None of these pesticides contaminated the runoff water from the neighboring upstream forested area. The concentrations of pesticides varied to a great extent with each storm runoff event. The loading rates of pesticides caused by the storm runoff depended on the length of the period after the applications rather than being correlated with precipitation. Using the data obtained from the regular observation and the storm runoff events, the annual loading rates of Simazin, Oxadiazon, Diazinon and Atrazine were calculated as 1,590, 362, 99.0 and 295 g/km2/year. The loadings from only three storm events observed in the study occupied 22 - 100% of these annual loadings. The annual discharging rates of Simazin, Oxadiazon and Diazinon were 4.2, 1.5, and 0.98%, respectively.

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