YU Wei1,2, YANG Haiquan1, GUO Jianyang1, TANG Xuyin1,3, ZHANG Zheng1,4, YANG Yongqiong2
（1. Institute of Geochemistry, Chinese Academy of Sciences, State Key Laboratory of Environmental Geochemistry, Guiyang 550081, China;
2. Guizhou Normal University，School of Geography and Environmental Science, Guiyang 550025, China;
3. University of Chinese Academy of Sciences, Beijing 100049, China;
4. Xi 'an University of Science and Technology, School of Surveying and Mapping Science and Technology, Xi 'an 710054, China）
Abstract: In order to clarify the temporal and spatial variation in the hydrochemistry of Lake Caohai, and to reveal the influence of water-rock interactions and the impact of human activities on the hydrochemistry, different water bodies, including Lake Caohai, rivers and ground water, were systematically sampled during the dry and wet seasons, and were subjected to the analysis of the controlling hydrochemical factors and main ion sources by methods such as Piper and Gibbs. The results indicate the hydrochemical types of Lake Caohai are mainly HCO3-Ca and HCO3-SO4-Ca-Mg, with HCO3- and Ca2+, which account for 48% and 44% of total anion and total cation, respectively, are the dominant ions. The water of Lake Caohai has obvious characteristics of river and groundwater input. The hydrochemical process of Lake Caohai is mainly affected by the weathering of carbonate rocks, such as calcite and dolomite and so on, and the human activities. It’s also affected by the dissolution of evaporate and sulfate rocks (gypsum and anhydrite). Overall, HCO3-, Ca2+, Mg2+ in lake water of Caohai are mainly from the weathering of carbonate rocks such as calcite and dolomite; SO42- is mainly derived from the dissolution of sulfate rocks; and K+, Na+, Cl-, NO3- are mainly affected by the urban sewage and agricultural effluent. According to the principal component analysis, carbonate-sulfate and silicate rocks contribute about 51% to the hydrochemistry of Lake Caohai, while, urban sewage, evaporation and biological effects contribute another 37%.
Key words: hydrochemistry; ion sources; rock weathering; human activity; Lake Caohai
EARTH AND ENVIRONMENT Vol.49, No.1, Tot No.339, 2021, Page 32-41