Study on water quality status and hydro-chemical characteristics ofshallow aquifer in mining area of Yulin City

In order to understand the coal mining in Yuheng North Area and Yushen Mining Area affected to the shallow aquifer in Quaternary, a hydro-chemical characteristics study and water quality evaluation work should be conducted. A descriptive statistic method, ion proportion coefficient method and Piper three line diagram method were applied to fully and systematically study the hydrochemistry characteristics of the shallow aquifer in Quaternary and the entropy weight-intimated value method was applied to evaluate the water quality. The study results showed that the hydrochemistry type in mining area of Yulin City mainly would be HCO3-Ca and HCO3-Ca·Mg. The overlimit indexes mainly were TDS, TH, Cl-, SO2-4, NO-2, NO-3, F- and CODCr.The hydrodynamic condition of the regional groundwater was good and the water replacement and circulation were fast. In the 42 water samples, the better than three standards of the groundwater quality standard were 62% and the main pollution factor was NO-3.The main causes of the pollution were the human activity and driving and the mining activities would have less influences to the groundwater in mining area of Yulin City.