Study On The Evolution Of Shallow Groundwater Chemical Field And Related Environmental Problems In Guanzhong Basin

The groundwater in Guanzhong Basin has many chemical types and complicated composition. Its bad quality led to local diseases in some places constantly and influenced people's living space. In recent years, variation of the groundwater chemical environment under human activities has resulted in some environmental problems in some places. The study on evolution of groundwater chemical field makes effect to know the formation and evolution character of groundwater chemical field, therefore provides scientific evidence for rational exploration and utilization of water resources and eco-environment protection.Based on field survey and indoor experiments, the paper mainly researches the evolution of groundwater chemical field in time and space in Guanzhong Basin and related environmental problems. The distribution characters of chemical type, degree of mineralization, hardness and ion content in shallow groundwater of 1980's, 1990's and present were summarized, and the main influencing factors were analyzed. Through the research, it demonstrates that spatial distribution of natural chemical field of shallow groundwater in the area is largely controlled by geology, terrain and hydro-geological conditions and has clear rule. From the zone in front of the mountain to the centre zone of the basin and from the upstream to the downstream, groundwater chemical function changes from dissolving and eluviating to concentrating, the degree of mineralization increases, groundwater chemical types vary from the single carbonic acid type to sulphuric acid type or chloride type, equivalent ratio of ion pair changes obviously. The character of evolution with time is that the change of groundwater chemical field mainly takes place in the north of Weihe River, in which human activities are strong, and little in the south of it. In the area, the chemical type is complicated, the natural groundwater chemical field evolves toward salinization and alkalination and groundwater quality tends to deterioration. Moreover, environmental problems, related to groundwater chemical field, including the problem between high fluorine distribution under natural condition and peoples health and the contamination problem of environmental materials released by people such as NO3-, COD, PO43-, are initially discussing. All these can provide scientific evidence for environment prediction, evaluation and administration.