| 西南地区典型森林水库土壤和沉积物汞的迁移转化特征 |
| 摘要点击 2211 全文点击 877 投稿时间：2017-09-06 修订日期：2017-10-10 |
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| 中文关键词 汞 未淹水土壤 沉积物 消落带 森林水库 |
| 英文关键词 mercury unsubmerged soil sediment hydro-fluctuation belt forest reservoir |
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| 中文摘要 |
| 以西南地区典型拦蓄筑坝形成的森林水库重庆四面山大洪海为研究对象，在湖边位置将从未被水淹没区域的土壤（未淹水区土壤）和沉积物进行原位置换实验，并对水库水体以及土壤总汞（THg）和总甲基汞（TMeHg）的变化进行了为期一年的监测研究.结果表明，四面山大洪海水库未受汞污染的影响，其水体THg[（1.89±0.72）ng·L-1]和TMeHg[（0.13±0.04）ng·L-1]的质量浓度均值远低于我国环境质量标准中Ⅰ类水质标准和国内外其他一些水库或湖泊，未淹水区土壤和沉积物中THg和TMeHg的含量也相应低于其他一些水库或湖泊；水体和土壤中THg和TMeHg的含量具有一定的季节性变化（暖季>冷季），其中TMeHg的季节性变化更明显，主要影响因素为气候和降雨量的变化；沉积物中THg和TMeHg的含量相对未淹水区土壤均有明显的升高，表明沉积物是水库汞储存的重要场所，同时也使沉积物成为水库汞（尤其是甲基汞）污染的潜在源；原位置换后的土柱THg和TMeHg含量在经过较短的时间即能与周围土壤达到平衡状态，特别是表层土壤，说明水库消落带能够加快汞的地球化学循环过程. |
| 英文摘要 |
| Mercury (Hg) has been regarded as a global pollutant due to its volatility and toxicity. The sediment in the reservoirs or lakes is an important compartment for Hg methylation and it has also been considered as a sensitive area of Hg. In this study, a typical forest reservoir surrounding by evergreen broad-leaved forest in Chongqing of southwest China was selected to investigate the migration and transformation of Hg in unsubmerged soil and sediment. The unsubmerged soil and sediment were also replaced to each other to observe the dynamics of THg and TMeHg concentrations in equilibrium processes. The results were as follows:① The THg and TMeHg mean concentrations in Dahonghai reservoir water were (1.89±0.72) ng·L-1 and (0.13±0.04) ng·L-1, respectively, which were lower than the first class water quality standards in environmental quality standard of China and other reservoirs or lakes, implying that this study area did not affect by Hg pollution. Meanwhile, the THg and TMeHg mean concentrations in unsubmerged soil and sediment were also lower than those in other reservoirs or lakes. ② Seasonal variations of THg and TMeHg concentrations in reservoir water and soil were both observed higher in warm seasons, and more obvious variations occurred for TMeHg which probably influenced by meteorological parameters, such as, temperature and rainfall. ③Compared with unsubmerged soil, the THg and TMeHg mean concentrations in sediment were both elevated, suggesting the sediment was an important sink of Hg. While, the sediment would be a source of Hg (especially TMeHg) with a high THg and TMeHg level. ④ The THg and TMeHg mean concentrations in unsubmerged soil and sediment after situ replacement were equilibrated with ambient soil in a short time (one or two months), implying the hydro-fluctuation belt of reservoir promoting the geochemical cycle of Hg. |
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