基于南黄海中部泥质区Pb稳定同位素的我国北方能源结构变迁示踪研究

Sediment records have been widely used to reconstruct environment change in the past century, which helps interpret the effects of anthropogenic activities on the environment. Energy restructuring has been frequently occurred in coal dominated North China during the last 50 years. As the amount of fossil fuel (mainly coal and petroleum) consumption soared, it produces enormous aerosol lead. Presently, Pb stable isotope ratios (206Pb/207Pb, 208Pb/207Pb) mainly serve as the proxy of Pb sources. Yet, there have few studies using these signatures to trace the historical energy restructuring, which was closely related with the production of aerosol lead. Therefore, this study tends to establish high resolution records of historical energy restructuring in Central Yellow Sea Mud (CYSM), which has stable depositional environment and is in the direction of East Asia winter monsoon. Based on 3 high quality sediment cores from CYSM and historical energy consumption data collected, we try to analyze the variations of 206Pb/207Pb and 208Pb/207Pb under different energy structures. The effect and relative contribution of leaded gasoline and coal on 206Pb/207Pb and 208Pb/207Pb will be evaluated. Thus, the effectiveness of 206Pb/207Pb and 208Pb/207Pb to trace historical energy restructuring of North China will be determined. This study tends to provide a new perspective on global environmental issues strongly linked to energy consumption, such as air pollution and greenhouse effect.

应用沉积物记录重建生态系统百年来的环境变迁，解析人类活动对环境的影响具有重要意义。近50年来，我国北方以煤炭为主的能源消耗量大幅攀升，能源结构不断调整。铅（Pb）多以气溶胶形式排放，与加铅汽油、煤炭等化石燃料消耗密切相关。当前，Pb稳定同位素（206Pb/207Pb、208Pb/207Pb）主要用于溯源，但尚未广泛用于解析与排放大气Pb的能源消耗活动和结构变迁的关系。基于此，本项目选择沉积环境稳定，处于东亚冬季风下风向的南黄海中部泥质区为研究靶区，以3根高质量柱状沉积物为研究对象，通过化学分析与历史资料统计，构建高分辨率Pb埋藏通量及其同位素沉积记录与能源消耗格局的对应关系，分析不同能源消耗格局下Pb同位素比值变化，评估南黄海中部泥质区Pb稳定同位素对我国北方能源消耗结构的指示意义，为研究与能源消耗密切相关的大气污染、温室效应等全球性问题提供新视角。

应用沉积物记录重建生态系统百年来的环境变迁，解析人类活动对环境的影响具有重要意义。近50年来，我国北方以煤炭为主的能源消耗量大幅攀升，能源结构不断调整。铅（Pb）多以气溶胶形式排放，与加铅汽油、煤炭等化石燃料消耗密切相关。当前，Pb稳定同位素（206Pb/207Pb、208Pb/207Pb）主要用于溯源，但尚未广泛用于解析与排放大气Pb的能源消耗活动和结构变迁的关系。基于此，选择处于东亚冬季风下风向的南黄海中部泥质区C3柱为研究对象，系统开展了C3柱基于210Pb方法的年代学、Pb元素及其稳定同位素（208Pb /206Pb、207Pb /206Pb）的研究, 解析了该区域Pb富集历史和能源消耗结构变迁的协同演化关系，剖析了Pb输入的来源、定量确定了大气输入途径的贡献，初步构建了我国北方近半个世纪以来能源消耗量变化和结构变迁对南黄海中部泥质区中Pb及其同位素沉积记录的影响模式。此外，还开展了中、低纬度不同陆地能源消耗结构下近海Pb及其稳定同位素特征的比较研究。结果显示：（1）研究区域Pb元素具有5阶段输入特征；（2）二端元模型计算显示在1973~2008期间，C3柱中经大气输入的Pb占37%~55%；（3）加铅汽油1970年代开始使用以及2000年停用，1997年亚洲金融危机、燃煤消耗量增加及占总能源消耗量的比重升高等能源消耗活动和结构变化皆显著影响了Pb同位素的沉积记录；（4）通过对不同能源结构影响下的泰国湾的Pb同位素研究表明，陆地人为活动和风化等自然过程均能导致Pb元素的富集，而Pb同位素的分析可定性或定量分辨不同途径来源对Pb的贡献。综上，南黄海中部泥质区中Pb同位素特征记录了陆地能源消耗量变化和能源结构变迁的历史。本研究揭示了南黄海中部泥质区Pb稳定同位素对我国北方能源消耗结构变化的指示作用，为研究与能源消耗密切相关的大气污染、温室效应等全球性问题提供新视角。