Characteristics Of Fluorine Storage In Groundwater In The Endemic Diseases Area And Water Quality Safety Assessment In Songnen Plain

Choosing Tongyu County as the study area, where endemic diseases are more serious than other places in Jilin province, based on field investigation and groundwater samples collection, testing, application of classical statistics and geostatistical analysis methods, the distribution and origin of fluorine in groundwater and groundwater chemical characteristics of Tongyu County were analyzed, and the safety of drinking water was evaluated. The conclusions from the study are as follows:1. It could be seen from the test results obtained from this survey, there were two sources of fluoride in groundwater in the study area, origining from Daxingan Mountain and the releasing of fluoride in aquifer and surrounding rocks. In Daxingan Mountain area, there were a lot of intrusive rocks and volcanic rocks with high fluoride content, and the weathering was intensive. The release coefficient of fluoride was 0.073-0.52, which was the main source of fluorine in groundwater. The other source was the release of fluoride in aquifer and surrounding rocks. Main fluorine minerals in the aquifer include: malladrite, prosopite and thomsenolite with the water-soluble fluorine content of 1.50-39.10mg/kg and 0.37-0.80mg/100 g which would directly enter into the groundwater. The surrounding rock(permeable layer or water layer) also contained a lot of fluorine, with the soluble fluorine content between 0.52-1.04mg/100 g, which would enter into the groundwater through the flow or infiltration.2. There was obvious consistency in the spatial distribution between various types of endemic fluorosis endemic areas and certain geological environmen. Geological environmental factors played a certain role in controlling the growth and severity of endemic fluorosis. However, due to the attribute of geological environmental factors are limited, the effect to fluoride poisoning was not the same. Among them, the distribution of groundwater geochemistry direction and water chemical component were controlled by the the hydrodynamic factors. Groundwater hydrogeochemical action was controlled by the morphology features through providing water chemical diversity places and desalinating groundwater.Among the various geological environmental factors which influenced the fluorosis and the severity of the disease, the dynamic conditions of groundwater were very important, and then was the landform factor.3. Based on the statistical analysis results of the chemical composition in groundwater, the main cations were Na+, Ca2+ and Mg2+, main anions were Cl-, HCO3-and SO42-. The content of F- ranged from 0.69 to 8.54mg/L and the mean value was 1.74mg/L with a coefficient of variation of 67.57%, which was moderate intensity variability. The results of Piper diagram showed that the water type of phreatic water was mainly HCO3-Na-Mg-Ca, and HCO3-Na-Mg was the main water type of quaternary confined water and HCO3-Na-Mg of Neogene confined water.4. Fluorine concentration was higher in the northeast of study area, and was lower in the southwest. It showed in vertical that the fluorine content in the groundwater of upper Pleistocene of Quaternary aquifer was higher than that of lower aquifer, and the fluorine content in the groundwater of lower Pleistocene of Quaternary aquifer was higher than that of tertiary system Taikang group aquifer, and Taikang group aquifer was higher than that of Daan group aquifer.Fluorine content was between 0.5mg/L and 11.10mg/L in quaternary system upper pleistocene series aquifer groundwater. Fluorine content is between 0.85 to 0.85 mg/L in the lower pleistocene series aquifer groundwater, which in Xinxing town to Wulanhua town area it was less than 1 mg/L with the area was about 300 km2. Fluorine content in groundwater of Daan group aquifer was between 0.92 mg/L and 0.92 mg/L.5.The groundwater quality was worst(?) and worse(?) through groundwater quality comprehensive evaluation, and there was almost no change in water quality types. The fluorine concerntration exceed the drinking water standard serious, and the biggest concerntration of the fluorine was 7.12 times larger than the standard.