Abstract Hydrothermal systems with active surface expressions are important natural source of atmospheric mercury. Here we report on the first simultaneous assessment of gaseous elemental mercury (GEM) and major volatiles (H2S and CO2) fluxes from the fumarolic system of Pisciarelli, currently the most active at the Campi Flegrei caldera (CFc), Naples (Italy). This was achieved via a GPS-synchronized Lumex and MultiGAS survey which extends similar investigations reported elsewhere. GEM concentrations measured in the fumarolic emissions were consistently above background air level close to the degassing area (mean ~ 8 ± 3 ng m−3 on average) and ranged up to 12,000 ng m−3. Our data evidenced pulsed sequences of GEM increases in the fumarole plume, closely matched by temporally consistent increases in CO2 and H2S (r2 = 0.9), supporting the idea that major volatiles, such as CO2 acts as potential carrier in transporting GEM within the magmatic/hydrothermal systems. The slope of the best fit calculated for the dispersion of our data provides a GEM/CO2 molar ratio of 1.1 × 10−8 and a GEM/H2S of 5 × 10−6, respectively. These ratios are comparable to those reported for both low (~ 100 °C) and high-T (~ 250 °C) fumaroles from non-explosive volcanic/hydrothermal degassing systems elsewhere. We adopted an ad-hoc method that combines video footages and gas measurements to obtain high precision concentration maps of gas emissions used to estimate the total atmospheric GEM, CO2 and H2S flux of about 0.0113, 225059 and 511 t y−1, respectively. The human health risk assessment related to the GEM emissions at Pisciarelli, confirms that, except for the degassing fumarolic area, all the main sites affected by the plume dispersion, always remain well below the safe threshold recommended by the health authorities.

中文翻译：

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Pisciarelli 的喷气式系统（Campi Flegrei，意大利）的大气热液排放的第一个同步汞和主要挥发物表征

摘要 表面活跃的热液系统是大气汞的重要天然来源。在这里，我们报告了来自 Pisciarelli 喷气系统的气态元素汞 (GEM) 和主要挥发物（H2S 和 CO2）通量的首次同时评估，该系统目前在 Campi Flegrei 火山口（CFc）最活跃，那不勒斯（意大利）。这是通过 GPS 同步的 Lumex 和 MultiGAS 调查实现的，该调查扩展了其他地方报道的类似调查。在烟气排放中测量的 GEM 浓度始终高于脱气区附近的背景空气水平（平均约 8 ± 3 ng m-3），范围高达 12,000 ng m-3。我们的数据证明了喷气孔羽流中 GEM 的脉冲序列增加，与 CO2 和 H2S 的时间一致增加密切匹配（r2 = 0.9），支持主要挥发物（如 CO2）作为潜在载体在岩浆/热液系统内运输 GEM 的观点。为我们的数据分散计算的最佳拟合的斜率分别提供了 1.1 × 10-8 的 GEM/CO2 摩尔比和 5 × 10-6 的 GEM/H2S。这些比率与来自其他地方非爆炸性火山/热液脱气系统的低 (~ 100 °C) 和高 T (~ 250 °C) 喷气孔报告的比率相当。我们采用了一种结合视频片段和气体测量的特殊方法来获得气体排放的高精度浓度图，用于估计大气 GEM、CO2 和 H2S 总通量分别约为 0.0113、225059 和 511 ty−1。与 Pisciarelli 的 GEM 排放相关的人类健康风险评估证实，除了脱气喷气区域，