The main point source of pollution of the Keumho river in Taegu, Korea, stems from waste from the areas of industrial complexes . Although it is widely accepted that pollutants in waste water negatively effects general water quality, it is difficult to evaluate the effluent effect because of varying conditions in ambient water and inconclusive knowledge of causative pollutants. To analyze the water in relation to the industrial effluent in the area, pH. temperature, conductivity, and Microtox toxicity of various river samples were measured. Water samples were collected every 2 hours for 36 hours from Keumho river and Dalseo stream. Data from continuous monitoring for 36 hours showed that effluent in Keumho river originated from Dalseo stream, which is near adjacent to industrial complexes. Change in toxicity and other factors tested during the 36 hours indicated that continuous monitoring was necessary for a satisfactory effluent toxicity test Furthermore, in addition to water quality monitoring, it was concluded that sediment toxicity also needed to evaluate effluent effects.