Characteristics of the main inorganic nitrogen accumulation in surface water and groundwat
Journal of Groundwater Science and Engineering Vol.7 No.2 Jun. 2019DOI: 10.19637/j.cnki.2305-7068.2019.02.008Characteristics of the main inorganic nitrogen
accumulation in surface water and groundwater of wetland
succession zonesZHOU Nian-qing1*, LI Tian-shui1, ZHAO Shan2, XIA Xue-min11 Department of Hydraulic Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China.2 College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China.Abstract: Based on the observation of a complete hydrological year from June 2014 to May 2015, the temporal and spatial variations of the main inorganic nitrogen (MIN, referring to NO3_-N, NO2~-N, NH/?N) in surface water and groundwater of the Li River and the Yuan River wetland succession zones are analyzed? The Li River and the Yuan River are located in agricultural and non-agricultural areas, and this study focus on the influence of surface water level and groundwater depth and precipitation on nitrogen pollution. The results show that NO3_-N in surface water accounts for 70%-90% of MIN, but it does not exceed the limit of national drinking water surface water standard? Groundwater is seriously polluted by Based on the groundwater quality standardof NH4+-N, the groundwater quality in the Li River exceeds Class III water standard throughout the year, and the exceeding months9 proportion of Yuan River reaches 58.3%. Compared with the Yuan River, MIN in groundwater of the Li River shows significant temporal and spatial variations owing to the influence of agricultural fertilization. The correlation between the concentrations of MIN and surface water level is poor, while the fitting effect of quadratic correlation between NH4+-N concentration and groundwater depth is the best (R2=0.9384), NO3_-N is the next (R2=0.5128), NO2_-N is the worst (R2=0.2798). The equation of meteoric water line is 8D =7.83618O+12.21, indicating that both surface water and groundwater come from atmospheric precipitation? Surface infiltration is the main cause of groundwater NH4+-N pollution. Rainfall infiltration in non-fertilization seasons reduces groundwater nitrogen pollution, while rainfall leaching farming and fertilization aggravate groundwater nitrogen pollution?Keywords: Wetland; Surface water; Groundwater; Nitrogen; CharacteristicsReceived: 15 Dec 2018/ Accepted: 26 Feb 2019IntroductionLake and wetland are widely distributed in nature. Lake and wetland pollution has the ten-dency to worsen in recent years because of human activities (XIONG Jian et al. 2016), especially nitrogen pollution (WANG Wei-qi et al. 2015). Nitrogen exists in wetland with various forms,*Corresponding author. Email: nq.zhou@tongji.edu.cnamong which NCh^N, NO2~-N and (themain inorganic nitrogen, abbreviated as MIN) are the mo就 important indicators of nitrogen pollution. Different combinations of MIN imply various kinds of water pollution (XIE Jian-hua, 2011), and causes different levels of impact on natural envi-ronment and human health (WU Hai-yan et al. 2015). Wetland succession zone is a place for sub-stance and energy exchanging between ground-water and surface water, and it is also a channel for pollutant to flow from lake to groundwater. Nitro-
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Characteristics of the main inorganic nitrogen accumulation in surface water and groundwat
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