To assess the effects of pesticides sprayed in golf links on aquatic organisms, twenty pesticides were assayed by acute toxicity test using rainbow trout Oncorhynchus mykiss. Susceptibility to several pesticides, i. e. captan, chlorothalonile, chlorpyrifos, diazinon, and fenitrothion, was measured at different developmental stages: embryo, sac fry, and fry. No remarkable difference in susceptibility was observed among developmental stages on four pesticides except for chlorpyrifos, which showed a remarked difference in susceptibility among the different stages. Of the 20 chemicals tested, the 96 hour median lethal concentration (96h-LC50) of less than 0.1mg/l was obtained in captan, chlorothalonile, thiuram, chlorpyrifos, and oxine-copper. On the other hand, 96h-LC50 exceeding 10mg/l was obtained in flutolanil, mepronil, benfluralin, and mecoprop. The 96h-LC50 values of several pesticides were lower than the current effluent guideline values for golf links, suggesting that the guideline value is inadequate to conserve fishes in natural waters.
