Study On Pore Water Hydrogeochemistry Evolution Of Riverbed Sedimentation Zone Under Condition Of Riverbank Filtration

Shenyang is the biggest city of the northeast, its water supply source is ground-water.Huangjia water source is a typical river bankfiltration site,where the groundwa-ter is mainly recharged from Liao River.Riverbed sedimentation zone has the strongest microbial activityd and the high-est content of organic matter.When river water infiltrates,the biogeochemical pro-cesses in the riverbed sedimentation zone have obvious impact on the groundawaterquality.Developping the study on pore water hydrogeochemisty evolution of the riv-erbed sedimentation and deeply analysising the content and involvedhydrogeochemisty processes of hydrochemistry components contribute to reveallingthe mechanism of water hydrogeochemisty evolution.What’s more,based onthem,people can analysis the evolution progress of water source quality in order toensure the security of water source supply.This article relies on the National Natural Science Foundation of China-Underthe influence of bnakfiltrtion,study on the biogeochemical behaviors of iron andmanganese in the hypolentic zone.On the basis of analysising the geological and hy-drogeological conditions,we study on pore water hydrogeochemisty evolution of theriverbed sedimentation,hoping to provide references to supply watersecuritily.Through the study,the following understandings are acquired.1. There is a vertical varying rule of the media characteristics of the riverbedsedimentation zone.When depth increases,the sand content inceases,but the organicmatter content decreases.2. Redox is the main driving force of the hydrogeochemistry evolution in theriverbed sedimentation zone.Near the river bank,there are three redox zones under the riverbed within90centimeters in depth. Transition zone of oxidation-reduction envi-ronment ranges from0to20centimeters.Organic carbon reduces large amount of ox-ygen and total nitrate. The zone of relative reduction environment ranges from20to60centimeters.The oxygen content is very little and the main redox is the reducingdissolved of manganese mineral. The zone of reductive environment ranges from60to90centimeters where the main redox is the reducing dissolved of iron mineral.3. Contents of dissolved oxygen,nitrate,total manganese and iron change greatlythrough the indoor column simulation experiment. When river water infiltrates slow-ly,oxygen and nitrate are reduced fast.On the contrary, total manganese and iron con-tents increase larger.Whether the media of sedimentations are sterilizated has littleimpact on the oxygen and nitrate reduction,but has big impact on the total manganeseand iron contents.The content of orgnic carbon in the infiltration water has a big im-pact on the redox.High dissolved orgnic carbon can reduce dissolved oxygen and ni-trate quickly.At the same time, manganese and iron minerals are dissolved.As a result,contents of total manganese and iron increase.4. According to the experiment results,the simulation of pore waterhydrogeochemistry of the riverbed sedimentation zone is studied.After the simula-tion,the rule of redox varying with time under different experiment conditions isquantificated.When water infitrates fast,redoxes are weak. When organic content ishigh,redoxes are strong.