PURPOSE: To enable the measurement of biological concentration of chemical compounds for such a short time as only a few days by determinig the intake speed and the excretion speed of the chemical compound when it is orally dosed to an aquatic animal once.

CONSTITUTION: A test tank with a capacity of 120l is kept at the temperature of 25°C. Twenty carps are put in the tank and made inured to the environment for 2 weeks. Then, they are dosed with a feed containing chemical compounds as listed at a rate of 1% of the weight per fish. The feed is 20% in the water content with a diameter of 3mm and a length of 3mm. Then, five each of the carps are sampled at a specified time interval and undergo an analysis as a whole after the removal of intestinal tracts thereof. From the results of the analysis, a graph is obtained which indicates a relationship of logarithmic values of the concentrations of the chemical compounds in the carps to the time passed after the dosage of the compounds. Based on the graph, the constant of the intake speed and the constant of the excretion speed are determined for each chemical compound and further, the ratio of both the speed constants is calculated.