摘要：A large amount of i-urobilin is present in the bottom sediment of urban rivers, and the value of distribution ratio (sediment/water) increase along the river, being higher at the river mouth. The adsorption equilibrium of i-urobilin is important to estimate the movement of i-urobilin as a fecal pollution indicator in the aquatic environment. A model adsorption experiment was carried out to determine the factors affecting the uptake of i-urobilin by the bottom sediment. The particle size of sediment affected the adsorption of i-urobilin. Furthermore, the content of i-urobilin in sediment agreed with the model adsorption experiment. It was reported previously that the content of i-urobilin and suspended solids in river water increased after rainfall. These indicated that i-urobilin moved with suspended solids, which would precipitate at the river mouth. These results suggested that sediment samples should be collected at the mouth of the river, where i-urobilin was concentrated.
