Metal ratio mixing models clarify metal contamination sources to lake sediments in Yunnan, China
Metal ratio mixing models clarify metal contamination sources to lake sediments in Yunnan, China
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云南湖泊沉积物金属比例混合模型研究
DOI：
10.1016/j.scitotenv.2022.153247
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发表时间：
2022-01-22
影响因子：
9.8
通讯作者：
Wu, Duo
中科院分区：
文献类型：
--
作者：
Bain, Daniel J.;Hillman, Aubrey L.;Wu, Duo
受污染的遗留沉积物有助于现代污染负荷，特别是微量金属。这些贡献很难量化，因为从沉积物记录中重建的金属历史不能轻易地分为遗留污染和并发污染。特别是，在解释沉积物记录时，很少考虑或量化存储在集水区土壤、崩积和河流环境中的遗留金属的再动员和输送的贡献。本文利用蒙特卡罗-马尔可夫链混合模型对中国云南3个湖泊的金属积累的扩展记录与端元化学进行了比较，以帮助确定沉积物的来源贡献。这种方法允许在一个具有数千年采矿和冶金历史的地区，通过大气和河流机制进行金属的归因。这些分析揭示了不同的源混合，并证明了湖泊记录对盆地沉积动力学的敏感性。特别是，这些湖泊系统中金属浓度升高的很大一部分似乎来自土壤的贡献，而不是来自冶炼排放物的大气沉积。土壤贡献最大的似乎是洱海，这是一个容易侵蚀的土壤与湖泊紧密相连的湖泊。此外，这些研究说明了混合方法的潜力，以适应和澄清金属来源和提取的不确定性，因为提取效率的差异可以纳入来源不确定性估计。最终，这些方法强调了在解释沉积物历史时考虑河流金属迁移的必要性。
Contaminated legacy sediments contribute to modern pollution loadings, particularly trace metals. These contributions are challenging to quantify as metal histories reconstructed from sediment records cannot be easily divided into legacy and concurrent contamination. In particular, the contribution from re-mobilization and delivery of legacy metals stored in catchment soil, colluvial, and fluvial environments are rarely considered or quantified when interpreting sediment records. Here, extended records of metals accumulation for a set of three lakes in Yunnan, China are compared with endmember chemistries using Monte Carlo-Markov Chain mixing models to help identify source contributions to the sediments. This approach allows attribution of metals transported by atmospheric and fluvial mechanisms in a region with a history of mining and metallurgy spanning millennia. These analyses reveal distinct source mixtures and demonstrate the sensitivity of lake records to basin sediment dynamics. In particular, substantial proportions of elevated metal concentrations in these lake systems seem to arise from soil contributions more than from atmospheric deposition of smelting emissions. The largest soil contributions seem to be in Erhai, a lake with erosion prone soils closely "connected" to the lake. Moreover, these invesigations illustrate the potential for mixing approaches to accommodate and clarify uncertainties in metal source and extraction as differences in extraction efficiency can be incorporated into source uncertainty estimates. Ultimately, these approaches emphasize the need to account for fluvial metal transport in interpretation of sediment histories.