title: Distributions, Early Diagenesis, and Spatial Characteristics of Amino Acids in Sediments of Multi-Polluted Rivers: A Case Study in the Haihe River Basin, China.
abstract: The Haihe River Basin, which is one of the most water-scarce and polluted river basins in China, has abnormally high nitrogen levels. In this study, total hydrolyzable amino acids (THAAs) were measured in surface sediment and sediment core samples in the Haihe River Basin to determine if amino acids were potential sources of ammonium, organic nitrogen, and organic carbon. The rivers were found to be in a state of hypoxia and contain abnormally high levels of ammonium and organic nitrogen. Additionally, NH₃-N was the predominant form of inorganic nitrogen in the surface sediments, while organic nitrogen accounted for 92.53% of sedimentary nitrogen. THAAs-C accounted for 14.92% of the total organic carbon, while THAAs-N accounted for more than 49.59% of organic nitrogen and 45.68% of total nitrogen. The major fraction of THAAs were protein amino acids. Three sediment cores of the most heavily polluted rivers also showed high levels of THAAs. Evaluation of the degradation index (DI) of sedimentary organic matter in sediments evaluated based on the THAAs revealed that most positive DI values were found in the downstream portion of the Ziya River Watershed. Additionally, the DI of surface sediment was correlated with THAAs (r² = 0.763, p < 0.001), as was the DI of sediment cores (r² = 0.773, p < 0.001). Overall, amino acids in sediments were found to be an important potential source of ammonium, organic nitrogen, and organic carbon.
authors.affiliation: State Key Laboratory on Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. zhaoyugreen@163.com.|University of Chinese Academy of Science, Beijing 100047, China. zhaoyugreen@163.com.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: State Key Laboratory on Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. bqshan@rcees.ac.cn.
authors.forename: Baoqing
authors.initials: B
authors.lastname: Shan
authors.affiliation: State Key Laboratory on Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. wztang@rcees.ac.cn.
authors.forename: Wenzhong
authors.initials: W
authors.lastname: Tang
authors.affiliation: State Key Laboratory on Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. hongzhang@rcees.ac.cn.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory on Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. rongnan420@163.com.|University of Chinese Academy of Science, Beijing 100047, China. rongnan420@163.com.
authors.forename: Nan
authors.initials: N
authors.lastname: Rong
authors.affiliation: State Key Laboratory on Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. yuekuiding@163.com.|University of Chinese Academy of Science, Beijing 100047, China. yuekuiding@163.com.
authors.forename: Yuekui
authors.initials: Y
authors.lastname: Ding
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D002681:China; D004784:Environmental Monitoring; D004787:Environmental Pollution; D019015:Geologic Sediments / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis; D014876:Water Pollution / Q000032:analysis*
chemical_list: D000596:Amino Acids; D014874:Water Pollutants, Chemical; D009584:Nitrogen
keywords: Haihe River Basin; Ziya River Watershed; amino acids; organic matter