The Study Of Environmental Geochemistry Of Thallium In Xiangquan Thallium Mineralized District Of He County, Anhui Province, China

Xiangquan Thallium deposit locates at Xiangquan town of He county, Anhui Province;the main ore body locates in southeast of Xiaolongwangshan. Thallium element is highly riched in deposit and may pollutes the surrounding environment. Based on basic theory of environment geochemistry, the occurrence, the transfer processes and the environmental impacts of thallium element in Xiangquan thallium mineralized district of He county, Anhui province have been investigated. The distribution and dispersion of thallium element in soil, ground and surface waters, sediment, crops and vegetation, fowls, human bodies have been examined. The pollution degree of thallium element is evaluteated and a transfer model of thallium element is put forward. Through leaching experiment of thallium ores, the thallium leaching-out law and influencing factors were discussed, and some suggestions were provided for prevention and cure of the possible thallium pollution in future mine exploitation. The main contents is as follows:1. Thallium content of soil in Xiangquan Thallium mineralized district is obviously higher than soil in unmineralized area, which indicates that thallium has been riched in soil of the investigated district. Most of the soil near the thallium deposit are polluted by thallium element.2. Most water in ponds and wells have not been obviously polluted by thallium, but hotsprings are polluted by thaillum and not fit for drinking. Thallium content of sendiments in Xiangquan Thallium mineralized district are higher than that in waters in referring area and lower than that of most soil;sediments are not harmful to environment in view of their current relation with people.3. Thallium content of crops and vegetation in this district is low, which shows most crops and vegetation have not been polluted by thallium element and different parts of vegetation absorb thallium without selectivity in amount. Thallium content of chook is also lower than safe edible value.4. The average thallium content in urine of Xiaoshanjing villagers is 1.76μg/l, which is higher than that of the healthy people and the ordinary villagers in nonmineralised district, but lower than safe critical value of 5μg/l. The average thallium contents in hair of Xiaoshanjing villagers is 3.13μg/l, which is similarto that of most healthy people. Our study proves that thallium in ores in Xiangquan thallium mineralized district has not migrated into the environment, and the amount of thallium in the Xiaoshanjing villagers's bodies through food chains is now still in the normal range. The villagers are healthy, but they show symptoms of thallium pollution.5. Transfer model of thallium in Xiangquan Thallium mineralized district is founded preliminarily. Thallium transfers into soil and water through weathering and leaching from ore of thallium deposit, and/or transfers into human body from drinking and feeding.6. Leaching experiment of thallium ores shows that release amount of thallium is high in different conditions. Release amount of thallium is at the maximum under leaching liquid of pH=2 and organic acid, but the release amount of thallium is not closely related with the time and speed of leaching. Curve fitting equation between release amount of thallium and leaching time is also established.7. Suggestions for future thallium pollution protection have been put forward according to present state of Xiangquan Thallium mineralized district and possible exploitation of thallium deposit.