Characteristics of nitrogen and phosphorus loading and migration in typical river networks in Taihu lake basin
LIU De-hong1,2,3, YU Ju-hua1, ZHONG Ji-cheng1, ZHONG Wen-hui3, FAN Cheng-xin1
1. State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China;
2. Agricultural College, Henan University of Science and Technology, Luoyang 471003, China;
3. School of Geography Science, Nanjing Normal University, Nanjing 210023, China
The nitrogen and phosphorus content in water and sediment in Taihu Lake basin river were studied, the diffusion flux of nitrogen and phosphorus at the sediment-water interface were determined by sediment core culture experiment, and the relationships between them were also discussed. The results showed that the content of nitrogen and phosphorus in water and sediment were high, the average concentrations of total nitrogen (TN) and total phosphorus (TP) in water column were 4.12mg/L and 0.16mg/L respectively, in sediment were 1658.76mg/kg and 712.25mg/kg respectively. Nitrate (NO3--N) was the main inorganic nitrogen form in water column. However, ammonium was the main inorganic nitrogen in the sediment. Significant differences were detected in the sediment oxygen demand (SOD), which was higher in the western and southern regions but lower in the northern region. The diffusion flux of inorganic nitrogen at the water-sediment interface were: NH4+-N, -188.08~329.45mg/(m2·h) (average 13.05mg/(m2·h)); NO3--N, -118.68~42.86mg/(m2·h) (average -28.09mg/(m2·h)); NO2--N, -18.37~-4.81mg/(m2·h) (average -8.22mg/(m2·h)) respectively and the diffusion flux of soluble reactive phosphorus (SRP) was -10.94~10.58mg/(m2·h) (average 1.34mg/(m2·h)). In general, the flux of NH4+-N released from sediment to overlying water, and which was positively correlated with loss on ignition (LOI) extremely significantly. The diffusion flux of SRP was positively correlated with TP and total dissolvable phosphorus (TDP) in the sediment significantly. The results indicated that the release of NH4+-N was involved with the decomposition of the organic matters in the sediment, and the release of SRP was mainly affected by TP and TDP in the sediment. On the overall view, the pollution of nitrogen and phosphorus was most serious in the water and sediment of the sampling sites in the western region, where the diffusion flux of nitrogen and phosphorus were also relatively higher. In the western region, the diffusion flux of the sites located in downstream region were higher than those of the sites located in the upstream region, which confirmed that human activities had huge effect on the loading of nitrogen and phosphorus and their migration in the typical river networks in Taihu Lake basin.
刘德鸿, 余居华, 钟继承, 钟文辉, 范成新. 太湖流域典型河网水体氮磷负荷及迁移特征[J]. 中国环境科学, 2016, 36(1): 125-132.
LIU De-hong, YU Ju-hua, ZHONG Ji-cheng, ZHONG Wen-hui, FAN Cheng-xin. Characteristics of nitrogen and phosphorus loading and migration in typical river networks in Taihu lake basin. CHINA ENVIRONMENTAL SCIENCECE, 2016, 36(1): 125-132.
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