| In this paper, a typical urban shallow water landscape lakes Handan south lake asthe research object，analyzes the formation of nitrogen in sediments and the possiblesources and pollution effect，And analyzed the lake water body in the lake watersediment interface p transformation of the migration process and influence factors.For the same type shallow eutrophic lakes nitrogen pollution control and researchprovides a theoretical basis for effectively. The specific research results are asfollows:(1) Using single-factor appraisal, comprehensive pollution index andcomprehensive nutrition index to evaluate the situation of the water quality.Evaluation results show that the lake high amounts of nitrogen, phosphorus and othernutrients in the water is serious, the south lake water quality at light eutrophicationlevel. In addition, physical and chemical factors of Nanhu change greatly whichinfluenced by season and pollution levels.(2) TN content in the south lake water is between2.50~8.44mg/L, NH+4-Ncontent is between0.77~2.66mg/L, NO3—-N content is between1.37~5.27mg/L,the maximum value all appeared in#3points, Zhu River estuary place. Thetime distribution of TN and inorganic nitrogen in water for winter and spring is higherthan summer and autumn. According to the space-time distribution of TN andinorganic nitrogen in water, the overall distribution of pollutants declines graduallyfrom west to east. Along the west bank of contaminants to the beyond FuYang riverregion the highest lake.(3) TN content in the south lake sediment variation range is58~147mg·kg-1,the average content of the whole lake is96mg·kg-1, the spatial distribution differenceis significant. Peak appeared in1point, namely the FuYang river estuary place；NH+4-N content range of6~14mg·kg-1, the average content of the whole lake is9.5mg·kg-1. Peak appears in the3points, namely the Zhu river estuary place; NO3—-Ncontent range is2~11mg·kg-1, the average content of the whole lake is5.8mg·kg-1,the spatial distribution difference was significant; Peak appeared in5points, namelythe FuYang river out of13.(4) Nitrogen nutrients South lake sediment mainly include organic nitrogen (Org -N), ammonia (NH+4-N), followed by nitrate (NO—3-N), and the NO—2-N rarely canbe ignored. NH+4-N TN ratio is about10.0%~24.8%, NO—3-N of TN ratio is about2.8%~2.8%, has accounted for the vast majority of Org-N content, the ratio is about71.1%~86.8%, inorganic nitrogen is very few.NH+4-N、NO—3-N content in South lake sediments changes with the seasons ismore gentle, NH+4-N content peak appeared in June, the NO—3-N content peak appeared before March. While TN Org-N content changes with the seasons is moreobvious, difference is more apparent. Its highest levels before March and December,namely0.136mg·g-1'0.080mg·g-1, since the spring and autumn presents a downwardtrend, especially in late July,which reduce to the lowest level throughout the year.(5) Through analysising TN、NH+4-N、NO—3-N content in different samplingpoints to the south lake sediments and various forms of overlying water nitrogen，shows that TN content in south lake sediments and TN concentration in overlyingwater has roughly similar trends. But the NO—3-N in larger range sediment content isdifferent from concentration of overlying water, NH+4-N is different in less point. Asthe temperature increases, the N/P is less.(6) Through the experimental simulation of sediment release, found that therelease of TN amount increases with the rise of temperature. Different pH values onthe release of nitrogen in the sediment quantity is not the same, the trend generally onthe rise.DO concentration plays a main role on the release of the concentrations ofdifferent nitrogen species in the sediments. When DO <1mg/L, NH+4-N is releasedfrom sediments, which is the main representative sediment nitrogen release；When theDO concentration increased, TN、NH+4-N releasing quantity to reduce, NO—3-Nreleasing quantity to increase gradually... |
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