Do volcanoes emit mercury? Understanding the behaviour of Hg in volcanic products.

火山会释放汞吗？

基本信息

批准号：
NE/C511180/2
负责人：
David Pyle
金额：
$ 20.82万
依托单位：
University of Oxford
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2006
资助国家：
英国
起止时间：
2006 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FC511180%2F2
关键词：
Do volcanoes emit mercury Understanding

项目摘要

This is a proposal to make some modern measurements of the quantities of volatile trace metals that are released to the atmosphere by volcanoes. Volcanic gases are often equated with sulphur. In fact, sulphur is just one component of volcanic gases; and in just the same way that sulphur from volcanoes can affect the atmosphere, so may other species. We wish to make measurements of mercury at volcanoes. Mercury is a curious element: in its elemental form (Hg(o)) it is very volatile, and is not usually very reactive. As a result, once it is in the atmosphere it will stay there for a long time (about a year), before eventually being removed. Mercury is of general interest because it is highly toxic [the cause, for example, of the condition described by the phrase 'mad as a hatter']. It has no 'useful' function for biological organisms, but becomes concentrated up the food chain. One of the big problems with the current understanding of natural mercury in the atmosphere is that the books don't balance: we don't know very well where mercury is released from; and we don't know where it ends up. It is possible that volcanoes contribute to this imbalance: some people think that volcanoes may release a large amount of mercury, perhaps as much as half of all natural emissions; others think that it is so small that it can be ignored. By making measurements close to the vent of two active volcanoes using some new and very sensitive equipment, we hope to resolve this problem: at the very least, we'll know how much mercury is released by steady, gentle activity at the world's persistently active volcanoes. These volcanoes might not hit the headlines, but our idea is that they are always there in the background, supplying gases and particles to the atmosphere. A second scientific problem that we want to look at is to understand how mercury escapes from molten lavas; in what forms it escapes (is it mainly in the gaseous form? or does some of it very quickly form very small particles? and if so , what happens to those particles?); and we want to use the way that mercury behaves to understand more about the extreme (hot, oxidising, chemically reactive) environment that is a volcanic plume. A third aspect that we also wish to study is to use the erupted rocks and minerals (at the same two volcanoes, Etna and Kilauea) to try and understand how mercury and its chemically-similar 'cousins' (metals including Cd, Zn, Cu) behave as a rock cools and crystallises. We think that mercury and cadmium, for example, should have a slight preference for certain minerals (clinopyroxene, feldspar), and that as a result their concentration in the melt won't change much during crystallisation, but may change a little by 'degassing'. We can test this idea using precise (laser) measurements of small samples of real rocks.

这是一项对火山释放到大气中的挥发性微量金属数量进行一些现代测量的提议。火山气体通常等同于硫磺。事实上，硫只是火山气体的一种成分；就像火山中的硫磺会影响大气一样，其他物种也会如此。我们希望测量火山中的汞。汞是一种奇怪的元素：其元素形式 (Hg(o)) 非常不稳定，并且通常不具有很强的反应性。因此，一旦进入大气层，它就会在那里停留很长时间（大约一年），然后最终被移除。汞受到普遍关注，因为它具有剧毒[例如，导致“疯狂如帽匠”一词所描述的情况]。它对生物有机体没有“有用”功能，但会集中在食物链中。目前对大气中天然汞的理解存在的一个大问题是书籍不平衡：我们不太清楚汞是从哪里释放的；我们不知道它最终会去哪里。火山可能会造成这种不平衡：一些人认为火山可能释放大量汞，可能占所有自然排放量的一半；其他人则认为它很小，可以忽略不计。通过使用一些新的、非常敏感的设备在两座活火山喷口附近进行测量，我们希望解决这个问题：至少，我们将知道世界持续活跃的火山活动稳定、温和的活动释放了多少汞。火山。这些火山可能不会成为头条新闻，但我们的想法是它们始终存在于背景中，向大气提供气体和颗粒。我们想要研究的第二个科学问题是了解汞如何从熔岩中逸出。它以什么形式逃逸（主要以气态形式？还是其中一些很快形成非常小的颗粒？如果是这样，这些颗粒会发生什么？）；我们希望利用汞的行为方式来更多地了解火山羽流的极端（热、氧化、化学反应）环境。我们还希望研究的第三个方面是利用喷发的岩石和矿物（在同一座两座火山，埃特纳火山和基拉韦厄火山）来尝试了解汞及其化学性质相似的“表兄弟”（金属，包括镉、锌、铜））表现为岩石冷却和结晶。例如，我们认为汞和镉应该对某些矿物（单斜辉石、长石）有轻微的偏好，因此它们在熔体中的浓度在结晶过程中不会发生太大变化，但可能会通过“脱气”而发生一些变化'。我们可以通过对真实岩石的小样本进行精确（激光）测量来测试这个想法。