Abstract
In this study, a new assessment of river environment using benthic fauna is proposed. Field observations for the samplings of water quality and benthic fauna were conducted at 5~12 points in the ten first-class rivers of Chugoku district. As a result, there wasn't any significant correlation relationship among the water quality (T-N) and the stable isotope ratios of nitrogen (δ15 N) in benthic fauna. However, δ15 N in benthic fauna have a clear relation with the land use ratio of urban and farm area in the catchment for each sampling point which was estimated using GIS analysis. This result indicates that the δ15 N in benthic fauna can be an indicator of the river environment.
