| The reservoir sediment as an important part of reservoir environment plays a key role in water quality of the reservoir, especially when the reservoir deposition comes to a certain extent, it will affect the normal operation of the reservoir, meanwhile has a huge impact on water quality. Comprehensive analysis of the reservoir sediment is a way to acquire the situation of the reservoir water quality and an essential research of solving the treatment of the future dredging sediment of the reservoir. It took the Biliuhe reservoir as the research object in this paper, and selected Dapu as the study area after field investigation and having a fundamental understanding of the status of deposition of the Biliuhe reservoir. After sample collection, analyzed the properties of the reservoir sediment, which including pH, particle size distribution, organic matter and heavy metals including Fe, Mn, Cu, Cd, Pb and Zn, to approach the composition content and distribution and provide countermeasure of the sediment after the future dredging of the reservoir. The research results of this paper are as follows:(1) It found that three entrances of the Biliuhe reservoir including Guiyunhua, Dapu and Zhongling both had a certain degree of deposition, and the deposition layers were obvious by field survey. While the reservoir was in low water period and the water level was under 53.28m that made the dredging now convenient and feasible.(2) The sediment of Dapu consisted of loam and sandy soil and the main consistence was loam. Soil types of sediment in different regions had no uniform law in the deposition process. Both sides of the river (not including the area near the national highway) had no obvious change of soil types, while main basins and the area near the national highway had significantly transformation of soil type.(3) The content of organic matter in upper surface sediment was significantly higher than the other layers in Dapu area. The ranges of the organic matter content in the upper surface, lower surface, middle and lower sediment samples were respectively 13.29?58.18, 6.25?69.48,6.68?56.68 and 3.90?51.52g/kg. The organic matter content in different area of the upper surface, lower surface, middle and lower sediment samples showed a trend of that the main flood area>the left side of the channel>the right side of the channel. The whole Dapu sediment samples had a high level in organic matter content, and there were respectively 90.48%,76.19%,76.19% and 66.67% of the upper surface, lower surface, middle and lower sediment samples that had a level of III in organic matter content from the second nationwide general soil survey.(4) The heavy metals content dates of the different layers sediment showed that the main flood area generally had higher contents than others. The content changes of different heavy metals on the longitudinal direction showed the following trends:the contents of Pb and Fe gradually increased from the bottom to upper layer, the contents of Mn, Cu and Zn all appeared a wave type, while Cd content showed V font. The results of heavy metals assessment showed that:the geoaccunulation index focused on the pollution caused by gradual accumulation of heavy metal, while potential ecological risk index focused on the soil environmental quality standard, the combination of which reflected that the heavy metal concentration degree is that Cd>Pb>Zn>Cu, and the pollution degree is that Cd>Cu>Pb>Zn.(5) The paper discussed the possibility of sediment reuse on farmland, and the results showed that the soil type of Dapu sediment was suitable for plant growth, rich in nutrient content, and heavy metals content except that Cd exceeded seriously were safety. It also discussed the countermeasures of Dapu sediment reuse from the point of physical remediation, chemical remediation, bioremediation, agricultural ecological restoration and combined remediation technology to solve cadmium pollution. |
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