Pollution mechanism and migration prediction of Cr(VI) in shallow groundwater in Jiaozuo area

Based on the investigation of the distribution characteristics of pollutant Cr(VI) in the shallow groundwater of Jiaozuo area, the paper analyzed the polluting mechanism of Cr(VI). The groundwater flow model and solute transport model were established with Visual MODFLOW software and using the model simulation, migration prediction of Cr(VI) pollutants in the shallow groundwater was accomplished. The results show that in the shallow groundwater of the study area, Cr(VI) pollution is very serious. The source of the pollution is the ashery of a power plant located in the southwest of Laojunmiao in Jiaozuo. The main pollution reason is that under the long-term leaching effect, Cr(VI) pollutants of fly ash piled up in the open air infiltrated and polluted the aquifer. The climate, the lithology of aeration zone, the groundwater chemical environment and human factors are the indirect causes of the increasing concentration of Cr(VI) of the shallow groundwater in this area. Simulation results show that in the next five years, influenced by landform and groundwater dynamic field, migration directions of Cr(VI) pollutants in the shallow groundwater are consistent with groundwater flow directions. The diffusion rate along the flow direction of Dasha river is more faster,and the pollution area increases gradually with time.