SONG Liuting1,2,3, LIU Congqiang3*, WANG Zhongliang3, TENGYanguo1,2, WANG Jinsheng1,2, LIANG Lili3, and BAI Li3
1 College of Water Sciences, Beijing Normal University, Beijing 100875, China 2 Engineering Research Center of Groundwater Pollution Control and Remediation, Ministry of Education, Beijing 100875, China 3 State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
Abstract TheAha Lake is a seasonal anoxic water system in the southwest of Guiyang City, Guizhou Province, China. Seasonal variations in SO42- concentrations and their isotopic compositions in lake water as well as in the tributaries were investigated in this study.The results showed that sulfate concentrations in river water range from 0.94 to 6.52 mmol/L and their δ34S values range from -14.9‰ and 0.9‰, while lake water has sulfate concentrations ranging from 1.91 to 2.79 mmol/L, and δ34S values from -9.8‰ to -5.9‰. It is suggested that coal mining drainage is the major source of SO42- in the Aha Lake. Rainfall, sewage discharge, sulfide oxidation and gypsum dissolution have made only limited contributions. Different depth-dependent distributions of dissolved SO42- and δ34S were developed for both DB and LJK in summer and winter. Due to water overturn, δ34S values display homogenous vertical distributions in winter and spring. While in summer and autumn, significant positive shifts of δ34S were clearly observed in epilimnion and bottom strata as a result of water stratification. High δ34S values in epilimnion may result from the retention of rainwater during water stratification. Dissimilatory sulfate reduction by bacteria was thought to be responsible for the increase of δ34S value in hypolimnion.
Key words Aha Lake; sulfur isotope; source; geochemical cycling
* Corresponding author, E-mail:liucongqiang@vip.skleg.cn
CHINESE JOURNAL OF GEOCHEMISTRY Vol. 30, No. 4, 2011, page 444-452
© Science Press and Institute of Geochemistry, CAS and Springer-Verlag Berlin Heidelberg 2011
