青藏高原中汞的分布特征及影响因素——以典型海洋性冰川小流域为例

本研究以青藏高原典型海洋性冰川的雪冰-径流水为研究对象，分析讨论了雪冰-径流水中汞浓度变化趋势及控制因素.结果表明，贡嘎山冰川中雪、冰样品的THg浓度略高于全球背景值，而明永冰川以及米堆冰川的雪、冰、水样品均处于全球背景水平.3个冰川所有雪样、冰样、水样的THg浓度平均值分别为（4.78±5.99）ng/L、（1.72 ±1.15）ng/L、（1.31±0.91）ng/L.不同的环境介质中THg浓度变化总体表现为：雪 > 冰 > 水，其主要受颗粒汞沉淀作用及气态单质Hg挥发作用的控制.贡嘎山的径流水中THg浓度表现为六月最高（7.48±2.22）ng/L，十一月最低（1.39 ±0.27）ng/L.所有雪冰-径流水体系中HgP与THg存在极显著的正相关关系，雪中HgP/THg最高，其次为冰，最低为径流水.贡嘎山径流水中的HgP/THg及月均THg输出变化趋势受径流量和降雨量的影响.主成分分析表明了本研究区域雪冰中THg浓度主要受大气颗粒物沉降及季风传输的影响.此外，相比于其他2个冰川，贡嘎山冰川由于更加靠近人类活动密集区域，更易受到人类活动的影响.

Distribution characteristics and influencing factors of mercury in Tibetan Plateau-Examples from typical marine glacial small watersheds

In this study, Hg and its speciation in snow, ice and streamflow in three typical tibetan marine glaciers were investigated to understand the controlling factors during Hg transport processes. Results show that THg (total Hg) concentrations of snow and ice samples in Gongga Glacier were slightly higher than the values of global background, while values in Mingyong Glacier and Midui Glacier were at the global background levels. The average THg concentrations of all snow, ice and water samples of three glaciers were (4.78±5.99) ng/L, (1.72±1.15) ng/L, (1.31±0.91) ng/L, respectively. The variation of THg concentration was in snow > in ice > in water. Such trend was mainly controlled by the processes of sedimentation of particulate Hg and the volatilization of gaseous elemental Hg. The THg concentration in the streamflow of Gongga was the highest in June (7.48±2.22) ng/L and the lowest in November (1.39 ±0.27) ng/L. The HgP was significantly correlated to the THg, and HgP/THg was the highest in snow, followed by ice, and the lowest in streamflow. The variation of HgP/THg and monthly average THg output in the streamflow of Gongga Mountain were controlled by streamflow and rainfall intensities. Principal component analysis further indicates that the THg concentration in snow and ice was mainly affected by atmospheric particulate deposition and monsoon transport. Compared with the other two glaciers, Gongga Glacier was more susceptible to influence by human activities because of much closer to the intensive populated areas.