Li Chengding, Zhang Qianggong, Kang Shichang, Liu Yongqin, Huang Jie, Liu Xiaobo, Guo Junming, Wang Kang, Cong Zhiyuan
Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China.
Environ Sci Pollut Res Int. 2015 Aug;22(16):12490-500. doi: 10.1007/s11356-015-4498-3. Epub 2015 Apr 24.
Mercury (Hg) in aquatic ecosystems is of great concern due to its toxicity, bioaccumulation, and magnification in the food web. The Tibetan Plateau (TP) is endowed with the highest and largest lakes on earth, whereas Hg distribution and behavior in lake waters are least known. In this study, surface water samples from 38 lakes over the TP were collected and determined for the total Hg (THg) concentrations. Results revealed a wide range of THg concentrations from <1 ng to 40.3 ng L(-1). THg in lake waters exhibited an increasing trend along the southeast to northwest transect over the TP. Strong positive correlations were observed between THg concentrations and salinity and salinity-related environmental variables, especially for total dissolved solids (TDS) and some of the major ions such as Na(+), K(+), and Cl(-), suggesting the enrichment of Hg in saline lakes. The large-scale geographical pattern of climatic and environmental factors shows a decreasing precipitation and an increasing evaporation northwards and westwards and thereby induces gradient-enhanced enrichment of soluble substances in lake waters, which are likely to complex more Hg in northwestern TP. Our study provides the first comprehensive baseline data set of Hg in Tibetan lake waters and highlights the concurrent high Hg and salinity, representing valuable references and fundamental rules in further understanding the behavior and fate of Hg in lakes over the TP and perhaps high-altitude regions beyond.
由于汞（Hg）的毒性、生物累积性以及在食物网中的生物放大作用，水生生态系统中的汞备受关注。青藏高原拥有地球上最高、最大的湖泊，然而湖泊水体中汞的分布和行为却鲜为人知。在本研究中，采集了青藏高原38个湖泊的地表水样本，并测定了总汞（THg）浓度。结果显示，总汞浓度范围广泛，从<1纳克/升至40.3纳克/升。湖泊水体中的总汞沿青藏高原东南部至西北部断面呈上升趋势。总汞浓度与盐度及与盐度相关的环境变量之间存在强正相关，特别是与总溶解固体（TDS）以及一些主要离子如Na⁺、K⁺和Cl⁻，这表明盐湖中汞的富集。气候和环境因素的大规模地理格局显示，向北和向西降水减少、蒸发增加，从而导致湖泊水体中可溶性物质的梯度增强富集，这可能使青藏高原西北部的汞络合更多。我们的研究提供了青藏高原湖泊水体中汞的首个综合基线数据集，并突出了汞和盐度同时偏高的情况，为进一步了解青藏高原及可能还有其他高海拔地区湖泊中汞的行为和归宿提供了有价值的参考和基本规律。
