Source identification and impact of landscape pattern on riverine nitrogen pollution in a typical urbanized watershed, Beijing, China

Jin Liu; Zhenyao Shen; Tiezhu Yan; Yucong Yang

doi:10.1016/j.scitotenv.2018.02.161

Source identification and impact of landscape pattern on riverine nitrogen pollution in a typical urbanized watershed, Beijing, China

Sci Total Environ. 2018 Jul 1:628-629:1296-1307. doi: 10.1016/j.scitotenv.2018.02.161. Epub 2018 Feb 20.

Authors

Jin Liu¹, Zhenyao Shen², Tiezhu Yan¹, Yucong Yang¹

Affiliations

¹ State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China.
² State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, PR China. Electronic address: zyshen@bnu.edu.cn.

PMID: 30045551
DOI: 10.1016/j.scitotenv.2018.02.161

Abstract

This study explored the sources of nitrate and the impact of landscape pattern on nitrogen pollution in the highly urbanized Beiyun River Watershed, China during 2016 by applying a dual stable isotope approach (δ¹⁵N-NO₃^-and δ¹⁸O-NO₃^-) combined with multiple statistical analyses. The sources of riverine nitrate principally originated from manure and sewage, nitrification of soil nitrogen, fertilizer nitrification, and atmospheric deposition. A Bayesian model was used to estimate the source contributions and results showed that manure and sewage were the major contributors to river nitrate with combined proportions of 77.59% and 89.57% in the rainy season and the dry season, respectively. Results from multiple stepwise regression indicated that the typical artificial land use types and landscape configuration metrics reflecting landscape fragmentation related well with riverine nitrogen variables for different seasons (R²>0.6). Industrial land, unused land and patch density of built-up land and road were positively correlated with riverine nitrogen over seasons, whereas the interspersion and juxtaposition index of forest land was negatively related with nitrate. Regulating built-up land and unused land, connecting forest land with other land use types and diminishing discharges of industrial and domestic wastewater would be effective ways to improve urban river water quality.

Keywords: Bayesian model; Land use; Nitrate; Source identification; Stable isotope; Water.