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Response of water quality to land use and sewage outfalls in different seasons
Xu, Jing Jin, Guangqiu Tang, Hongwu Mo, Yuming Wang, You-Gan Li, Ling
Xu, Jing
Jin, Guangqiu
Tang, Hongwu
Mo, Yuming
Wang, You-Gan
Li, Ling
Abstract
To better manage water environment in highly polluted rivers, the influence factors on water quality need to be investigated. With the effects of oxygen-demanding contaminants, it is difficult to resolve the complex interdependencies of the various factors using conventional methods. The Bayesian Networks (BNs), in which each variable only depends on its immediate parent variables, can solve this problem. In this study, the BNs were developed to assess the impacts of land use and sewage outfalls on Ammonia Nitrogen (AN) and Dissolved Oxygen (DO) concentrations in the Huaihe River Basin (HRB) for different seasons and spatial scales, where AN was a typical oxygen-demanding contaminant and the most serious contaminant in the area. The BNs gave the best explanations for variations in AN (NSE = 0.80) and DO (NSE = 0.72) concentrations by using land use and sewage outfalls data at the local scale (less than 20 km radii around monitor stations), suggesting that controlling water contaminant sources at local scales can improve water quality efficiently. AN negatively affected DO concentration, which was more significant in dry seasons. Wastewater from sewage outfalls was the largest contributor (26.2%) to AN pollution in dry seasons, which was weakened in wet seasons by an intensive dilution process. Farmland acted as a “sink” in dry seasons and as a “source” in wet seasons. The transition between two states was caused by large variations in surface runoff between dry and wet seasons. Urban land made a disproportionately large contribution to water pollution compared to other kinds of land use. These findings improve our understanding of influence factors on water quality and will contribute to effective river management.
Keywords
ammonia nitrogen (AN), dissolved oxygen (DO), Bayesian networks, spatial scales, land use, sewage outfalls
Date
2019
Type
Journal article
Journal
Science of the Total Environment
Book
Volume
696
Issue
Page Range
1-11
Article Number
Article 134014
ACU Department
Institute for Learning Sciences and Teacher Education (ILSTE)
Faculty of Education and Arts
Faculty of Education and Arts
Files
Relation URI
Source URL
Event URL
Open Access Status
Published as green open access
License
File Access
Open
Controlled
Controlled