The Influence Of Hydrochemistry And Water Cycle For The Formation Of High Fluorosis Groundwater In Northern Plain Of Shandong Province

Fluorine is one of the essential trace elements for people. However, the excess fluoride of body can produce systemic physiological poisons, known as fluorosis. Fluoride water is important causes of excess fluorine element in the human body as well as a variety of the diseases generated by high fluoride. Endemic fluorosis is widely distributed in northern plain of Shandong province. People used to drink high-fluorine groundwater for a long time in the region, so that people will have excessive intake of fluorine element. Therefore, we should make survey of the groundwater and geological conditions and analysis water samples to identify the distribution of fluorine content of groundwater in the area, as well as to search the causes and evolution of the high-fluorine groundwater.According to hydrochemistry analysis,we draw hydrochemistry distribution, fluorine content distribution of different aquifers in the region and piper three-line diagram to research hydrochemistry type and fluoride ions distribution and quantitatively analyze the correlation of F- with Na+, Ca+, Mg+, to deduce the influence of water chemical environment for high fluoride water formation. According to the data of the stable isotopes D and 18 O, drawing diagrams comparing with the precipitation line to study the source and rule of groundwater recharge; calcluating and comparing the deuterium excess parameter(d) to search the retention time of groundwater in the aquifer, in order to find out the influenced of groundwater cycle for the high fluoride water formation.We draw the following conclusions: Water Chemical Characteristics in Northern Shandong fluorine water is obvious, high fluoride water chemical type is mainly Na cation type and HCO3·Cl anion type; with increasing of aquifer depth and the Fconcentration, hydrochemistry type is more focused on the HCO3-Na type; fluorine water is weakly alkaline. In the weak alkaline environment, the fluoride separate out from fluorine minerals of the aquifer, and due to the alkali metal, making F ions highly soluble, keeping stable in the groundwater.The result of isotopic analysis displays that high fluorine groundwater usually has four characteristic: little recharge sources, slow update, gentle runoff, poor drainage. Due to the long stay of groundwater, groundwater enhances interaction with fluoride-rich rock in the aquifer while promoting the control of groundwater hydrochemistry environment, eventually leading to the rise of groundwater fluorine content at this area.