Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Environ Sci Technol. 2020 Jul 7;54(13):7901-7910. doi: 10.1021/acs.est.0c01849. Epub 2020 Jun 19.
With global warming, the melting of glaciers can result in the release of pollutants into the environment. For remote Alpine lakes, both atmosphere-deposited anthropogenic pollutants and glacier-released pollutants can eventually sink in the sediment. To date, there has, to the best of our knowledge, been no attempt at quantifying the contributions of these processes to the accumulation of pollutants in glacial lake sediment. To fill this gap, a semi-enclosed proglacial lake located in the southern Tibetan Plateau was chosen and a 28 cm sediment core, which can be dated back to 1836, was used to explore the temporal trends of trace elements, Hg, and black carbon (BC) during the past two centuries. Geochemical indicators (Rb/Sr, Ti-Zr-Hf, and sedimentary rate) in sediment showed an overall continuous warming of the lake, while the temporal trends of fluxes of toxic elements and BC were broadly associated with their emission patterns. By using a positive matrix factorization model, the contribution of the anthropogenic source rose from <10% in the 1850s to >40% after the 1980s. However, the signal of glacial meltwater release was also distinct, and the greatest contribution of ice-snow meltwater reached up to 61% in the 1950s. Regarding the most recent two decades, 90% of pollutant deposition in the Tibetan sediment can be attributed to the combined forces of primary emissions and glacial release.
随着全球变暖，冰川融化会导致污染物释放到环境中。对于偏远的高山湖泊，大气中沉积的人为污染物和冰川释放的污染物最终都会沉降在沉积物中。迄今为止，我们还没有尝试量化这些过程对冰川湖沉积物中污染物积累的贡献。为了填补这一空白，选择了青藏高原南部的一个半封闭的冰川前缘湖泊，并使用 28 厘米的沉积物芯，该沉积物芯可以追溯到 1836 年，以探索过去两个世纪中微量元素、汞和黑碳 (BC) 的时间趋势。沉积物中的地球化学指标（Rb/Sr、Ti-Zr-Hf 和沉积速率）表明湖泊整体持续变暖，而有毒元素和 BC 的通量的时间趋势与它们的排放模式大致相关。通过使用正矩阵因子分解模型，人为源的贡献从 19 世纪 50 年代的<10%上升到 20 世纪 80 年代后的>40%。然而，冰川融水释放的信号也很明显，在 20 世纪 50 年代，冰雪融水的最大贡献达到了 61%。关于最近的二十年，青藏高原沉积物中 90%的污染物沉积可以归因于原始排放和冰川释放的共同作用。
