SONG Liu-ting1,2,3, WANG Zhong-Liang3, TENGYan-guo1,2, WANG Jin-sheng1,2, LIANG Li-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: Physico-chemical parameters, dissolved trace metal ions and particulated trace metals were investigated for their distributions and transformations during summer and winter in Aha Lake, Guizhou province. In summer, thermal and chemical stratifications were well established while water overturn occurred during winter. The biogeochemical cycling probably play an important role in the distribution of dissolved Si, dissolved organic carbon (DOC), Mn, Fe, Cr, Co, Ni, Zn and Mo during summer stratification. In summer, significant increase of dissolved Mn, Fe, Co and Ni were clearly observed in the bottom as a result of degradation of organic matter and the redox cycling of Fe and Mn. The Mn concentration was much higher than Fe concentration, indicating that Mn cycling is stronger than that of Fe. Only a slight increase of Cr concentration occurred in Aha Lake in summer. Besides, metal diffusions from sediment porewaters may also have some contribution to the increase of metal ions in the bottom. In contrast, strong decrease of Zn and Mo concentrations appeared in the bottom due to the formation of metal sulfides and metal molybdates. There were significant enrichments of particulated Mn, Fe, Cr, Co, Ni, Zn and Mo just near the redox boundary, which were induced by water-particle interactions including adsorption/desorption, redox cycling of Fe and Mn oxides and hydroxides. As for Zn, Mo and Ni, the formation of metal sulfides seems to be another contributor to the increase of pariculated Zn, Mo and Ni.
Key words：Aha Lake; biogeochemical cycling; trace metal elements; water-particle interaction
EARTH AND ENVIRONMENT Vol. 40, No.1, Tot No.287, 2012, Page 9-17
