Peng Haijun, Rong Yimeng, Chen Di, Sun Ruiyang, Huang Jie, Ding Hanwei, Olid Carolina, Yan Haiyu
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; CAS Center for Excellence in Quaternary Science and Global Change, Xi'an, 710061, China.
State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
Chemosphere. 2023 Mar;316:137855. doi: 10.1016/j.chemosphere.2023.137855. Epub 2023 Jan 12.
Mercury (Hg) is a potentially toxic element that can be transported globally through the atmosphere, once deposited in the environment, has strong bioaccumulation and extreme toxicity in food webs, especially in wetland ecosystems. Anthropogenic Hg emissions have enhanced Hg deposition by 3-5 times since the industrial revolution, and the mining and smelting of Hg ore are important emission sources. However, the dynamics in Hg deposition around the largest Hg mine in China before the industrial revolution and their driving forces remain poorly explored. Here we reconstruct the atmospheric Hg depositional fluxes (named here Hg influx (Hg)) during the Holocene using a 450-cm alpine wetland sediment core taken from the Jiulongchi wetland, which is only 65 km to the Wanshan Mercury Mine. Our record shows an abrupt rapid increase in Hg concentration since 2500 cal yr BP, suggesting that Hg mining in southwest China may have started before the establishment of the Qin dynasty. Two major Hg peaks were found during the periods 10,000-6000 and 6000 - 3800 cal yr BP, with an increase in Hg deposition by a factor of 4-8. These two peaks are also found in other terrestrial archives from several sites across the Northern Hemisphere. We speculate that critical millennial-scale climate changes, i.e., the Holocene Climatic Optimum (HCO) and the Mid-Holocene Transition (MHT), were the potential triggers of these two Hg peaks. This study highlights the importance of climatic variability and local Hg mining in controlling atmospheric Hg deposition during the Holocene.
汞（Hg）是一种具有潜在毒性的元素，它可通过大气进行全球传输，一旦沉积在环境中，在食物网中具有很强的生物累积性和极高的毒性，尤其是在湿地生态系统中。自工业革命以来，人为汞排放使汞沉积增加了3至5倍，而汞矿的开采和冶炼是重要的排放源。然而，中国最大汞矿在工业革命前汞沉积的动态变化及其驱动因素仍未得到充分研究。在此，我们利用取自九龙池湿地的一个450厘米长的高山湿地沉积物岩芯重建了全新世期间的大气汞沉积通量（此处称为汞流入量（Hg）），该湿地距离万山汞矿仅65公里。我们的记录显示，自公元前2500年校准年以来汞浓度突然快速增加，这表明中国西南部的汞开采可能在秦朝建立之前就已开始。在公元前10000年至6000年和公元前6000年至3800年期间发现了两个主要的汞峰值，汞沉积增加了4至8倍。在北半球多个地点的其他陆地记录中也发现了这两个峰值。我们推测，关键的千年尺度气候变化，即全新世气候适宜期（HCO）和全新世中期转变（MHT），是这两个汞峰值的潜在触发因素。这项研究突出了气候变异性和当地汞开采在控制全新世期间大气汞沉积方面的重要性。
