Quality Analysis And Evaluation On Shallow Groundwater In Chang'an Area Of Xi'an

Abstract: The shallow groundwater is the main drinking water source in the countryside, and the quality of that affects people's health directly. Therefore, it is of great importance to study the quality of shallow groundwater. Based on the study of a typical landform of this area, this paper analyzed the reason why the elements exceed the accepted figure and pointed out the influence of soil layer type and the thickness of soil layer. This paper also revealed the change characteristic of shallow groundwater elements in loess plateau area. Through the analysis of the reasons of underground water pollution in this area, the preventing and controlling measures to keep the pollution away was proposed, and these will provide the basis to reduce the underground water pollution and to improve the quality of water.22 shallow groundwater from different places had been sampled from terrace and loess tableland in Du Quzhen and Wei Quzhen of Chang'an district, those water samples were came from the soil seep out water and different depth of well. Those samples had been sampled during September and November in 2005. The pH value, the temperature, the conductivity, the fluorine, the manganese, the iron, the zinc, the copper, the chromium, the cadmium, the selenium, the lead, the mercury and the arsenic of 44 water samples had been analyzed. The pH value, the temperature and the conductivity were measured by the multi parameters meter in the field; The fluorine (F)measured by a fluorine; The manganese(Mn),the iron(Fe),the zinc(Zn),the copper(Cu),the chromium (Cr), the cadmium (Cd), the selenium (Se), the lead (Pb) measured by the Atomic Absorption Spectrometry; the mercury (Hg), the arsenic (As) measured by the Atomic Fluorescence Spectrometry. Analysis results shows that the fluorine, the manganese, the iron and the zinc content have exceeded the accepted figure in some place. According to the national standard method of F value law, had been carried out critical appraisal and at the same time the shortcoming of national standard method of F value law had been discussed. Based on that one modified formula had been proposed, the quality of shallow groundwater in this area had been done by using that formula. Finally the reason why the fluorine, the manganese, the iron, the zinc content exceeds the accepted figure in those samples had been discussed, at the same time the relationship among physiognomy, soil stratum depth and the element content of groundwater had been...