Distribution Of Carbon,Nitrogen, Phosphorous And Sulfur As Well As Their Correlation In Sediments Of Xinyi Riverway In Harbin

With accelerating of urbanization and increasing of population, urban river water environment appear the prevalence of the phenomenon of water pollution under pressure from all sides. Xinyi riverway is one of the three inland rivers in Harbin, and its pollution has been serious in recent years. Especially black and odorous as well as eutrophication of water bodies not only affects the water quality and primary productivity, but also seriously affected the physical and mental health of residents and the city’s image. The four nutrient elements, such as carbon, nitrogen, phosphorus and sulfur, are the main affecting factors to the eutrophication and black and odorous water.The sediment is an important part of the water body, and the main place where pollutants stored. When external conditions change, contaminants in the sediment will be released into the overlying water, causing secondary pollution, and increasing the pollution load of water bodies. Therefore, to study on the law of transmission and storage of pollutants in sediments and pollution control countermeasure has great significance to repair the urban river ecosystem.By taking Xinyi riverway as the research object, the paper analyzed the horizontal and vertical distribution characteristics of organic carbon, total nitrogen, total phosphorus and acid volatile sulfide contents in sediment, as well as their correlation. The study aimed to reveal the deposition law of carbon, nitrogen, phosphorus, sulfur in sediment and their contribution to the endogenous pollution of water body, and provide a scientific basis for prevention and treatment of urban river eutrophication, blackening and stink of the water and recovery of ecological functions of urban riverways. The study results are described as follows:1) Organic carbon, total nitrogen, total phosphorus contents of Xinyi riverway surface sediments (0-5cm) were higher as a whole than those in lakes. The acid-volatile sulfide content ranges in Xinyi sediments were similar to those in offshore sediments. There were significant correlations between the total organic carbon, between total nitrogen, between total phosphorus, between acid volatile sulfide contents in surface sediments and chemical oxygen demand, total nitrogen, total phosphorus, sulfate contents in overlying water respectively.2) There were obvious vertical distribution characteristics of the total organic carbon, total nitrogen, total phosphorus and acid volatile sulfide contents in Xinyi sediments. In general, total organic carbon, total nitrogen, acid volatile sulfide contents increased firstly and later decreased with sediment depth increasing; Their maximum contents appeared5-20cm sediment depth range for different sampling points in general. In Xinyi sediments, the distribution characteristics of total phosphorus contents were complex:for some sampling sites, maximum contents appeared the surface layer (0-5cm) of sediments, and for the other sampling sites, maximum contents appeared the deeper layers (5-20cm) of sediments.3) In the vertical direction, there were no significant correlation between the total organic carbon and total nitrogen contents in Xinyi sediments. For some sampling point sediments, correlations were very significant not only between the total organic carbon and total nitrogen contents, but also between the total phosphorus and total nitrogen contents, however, correlation was not significant generally for most sampling points. For some sampling point sediments of Xinyi riverway, the organic carbon come from biological components of aquatic; for some sampling point sediments, the organic carbon come from land-based sources; for the other sampling point sediments, the organic carbon come from both of them. Nitrogen is the main limiting factor for the water eutrophication of Xinyi riverway.4) In the vertical direction, there was a significant correlation between the acid volatile sulfide and total organic carbon contents in the sediment. There were positive correlations between the acid volatile sulfide and total nitrogen contents generally, but correlations were not significant. In some sampling points, there were negative correlations between the acid volatile sulfide and total phosphorus contents; there were positive correlations in the other sampling points, some of which appeared significant positive correlation.In recent years, point source pollution of Xinyi riverway has gotten a certain degree of control with pollution prevention and treatment proceeding, however, the pollution of Xinyi riverway still exist further exacerbated trend due to endogenous pollution and not-point source pollution. The ecological restoration should be the main way in the treatment of Xinyi riverway.