title: Effects of land-use patterns on in-stream nitrogen in a highly-polluted river basin in Northeast China.
abstract: This study investigated the effects of land-use patterns on nitrogen pollution in the Haicheng River basin in Northeast China during 2010 by conducting statistical and spatial analyses and by analyzing the isotopic composition of nitrate. Correlation and stepwise regressions indicated that land-use types and landscape metrics were correlated well with most river nitrogen variables and significantly predicted them during different sampling seasons. Built-up land use and shape metrics dominated in predicting nitrogen variables over seasons. According to the isotopic compositions of river nitrate in different zones, the nitrogen sources of the river principally originated from synthetic fertilizer, domestic sewage/manure, soil organic matter, and atmospheric deposition. Isotope mixing models indicated that source contributions of river nitrogen significantly varied from forested headwaters to densely populated towns of the river basin. Domestic sewage/manure was a major contributor to river nitrogen with the proportions of 76.4 ± 6.0% and 62.8 ± 2.1% in residence and farmland-residence zones, respectively. This research suggested that regulating built-up land uses and reducing discharges of domestic sewage and industrial wastewater would be effective methods for river nitrogen control.
authors.affiliation: Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: buhm2004@163.com.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Bu
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Meng
authors.affiliation: Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Xianfang
authors.initials: X
authors.lastname: Song
mesh_terms: D000383:Agriculture / Q000706:statistics & numerical data; D002681:China; D004784:Environmental Monitoring; D005308:Fertilizers; D009584:Nitrogen / Q000032:analysis*; D045483:Rivers; D014507:Urbanization / Q000639:trends; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D005308:Fertilizers; D014874:Water Pollutants, Chemical; D009584:Nitrogen
keywords: Isotope mixing models; Land use; Landscape metrics; Nitrate isotopes; Nitrogen pollution; Nitrogen source contributions