Study On Iron Biogeochemistry And Environmental Impact Of Sediment In The Bottom Sediment Of Shifosi Reservoir

Shifosi Reservoir is the only control project on the main stream of the Liaohe River in Liaoning Province.It is a multi-purpose reservoir that integrates flood control and urban water supply functions.The interaction between inland surface water and groundwater is very strong.The surface water in the reservoir area recharges the groundwater through the leakage of sediment at the bottom of the reservoir.Therefore,the sediment at the bottom of the reservoir plays a filtering and protection role in the process of replenishing the surface water to the groundwater.Research on chemical action can understand the characteristics,scope,structure,and environmental properties of the hydraulic exchange between the surface water and groundwater in flood-detention plain reservoirs,and reveal the main influencing factors that control the behavior of iron and manganese in the sediments of the bottom of the reservoir and their main mechanism of action.It is of great scientific significance to enrich the content of biogeochemical research on the interaction between surface water and groundwater,and to ensure the safety of drinking groundwater supply.Through the investigation and analysis of regional geomorphology and geological conditions,we can grasp the formation and spatial distribution characteristics of sediments at the bottom of the reservoir.Through the analysis of hydrogeological conditions and surface water and groundwater quality evaluation of the reservoir area,it is determined that the surface water of Shifosi Reservoir can be regarded as Class IV water,and the comprehensive category of groundwater quality is classified as Class IV.Provide technical basis for interaction.The physical and chemical properties of the bottom sediment samples were tested,and the Tessier five-step continuous extraction method was used for mineral detection and iron morphology detection of the bottom sediment of the reservoir.The iron minerals in the bottom sediment of the reservoir were mainly amorphous iron oxide,The highest content of organically bound iron in the effective form of iron.The 16 S amplicon sequencing method was used to detect the bacterial community in the sediment at the bottom of the library.The detection results showed that the species diversity was high,and the composition of the different sample groups was not very different.The dominant strain was Proteobacteria.The release test of the iron element was carried out by static leaching,and it was found that the reduction of iron in the acidic environment is very strong,the reduction of iron in the alkaline environment hardly occurs,and the strength of the reduction of iron in the neutral environment is moderate.In addition,the test group with microorganisms had far better iron release effect than the sterilization test group.Through the dynamic test of the soil column,it is found that the oxidation zone,the reduction zone of manganese,and the reduction zone of iron are in order from top to bottom in the simulated column,and no SO42-reduction zone is found in the simulated column.Combined with the detection results of the bacterial community,the effect of iron on the function of the microbial community was analyzed.The iron respiration function accounted for a certain proportion in the bacterial community function.The relationship between enrichment was investigated,and it was found that the higher the iron content in the soil at the bottom of the Shifosi Reservoir,the lower the heavy metal cadmium content in cattails.