LAUSR

Abstract The components and structural characteristics of dissolved organic matter (DOM) in the overlying water were studied using various spectroscopy in Beiyun River. The relationship between the DOM composition and water quality was discussed. The result declared that the overall pollution of the Beiyun River was serious, and that the DOM content of the overlying water was between 9.60 and 28.70 mg/L. The DOM was mainly composed of humic-like substances (72.83%), proteins (9.49%), and microbial metabolites (17.68%). Furthermore, the structure and composition of DOM affected the nutrition level of river and reflected the water quality to some extent. Especially, the humification degree (SUVA254) of DOM can indirectly reflect the content of different types of nitrogen in the overlying water. Thus, some preliminary advice has been proposed to improve water quality by analyzing the content, composition and structural characteristics of DOM in the overlying water. These results offer novel ideas for the management of the Beiyun River.