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

这是一项建议，对火山释放到大气中的挥发性痕量金属进行一些现代测量。火山气体常常被等同于硫磺。事实上，硫只是火山气体的一种成分；就像火山产生的硫会影响大气一样，其他物种也可能会影响大气。我们希望对火山的水银进行测量。汞是一种奇怪的元素：它的元素形式(汞(O))非常不稳定，通常不太活泼。因此，一旦它进入大气层，它将在那里停留很长一段时间(大约一年)，最终被移除。人们普遍对汞感兴趣，因为它具有剧毒[例如，它是短语‘疯狂如帽匠’所描述的疾病的起因]。它对生物有机体没有‘有用’的功能，但在食物链上变得集中。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出来的；我们也不知道它最终会到哪里去。可能是火山导致了这种不平衡：一些人认为火山可能会释放大量汞，可能多达所有自然排放的一半；另一些人认为它太小了，可以忽略不计。通过使用一些新的非常敏感的设备在两个活火山喷口附近进行测量，我们希望解决这个问题：至少，我们将知道世界上持续活火山的稳定、温和的活动释放了多少汞。这些火山可能不会成为头条新闻，但我们的想法是，它们总是在背景中，为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是如何从熔岩中逸出的；它以什么形式逸出(它主要是以气体的形式逸出吗？或者它中的一些会很快形成非常小的粒子？如果是这样的话，这些颗粒会发生什么？)；我们想利用汞的行为方式来更多地了解作为火山羽流的极端(高温、氧化、化学反应)环境。我们也希望研究的第三个方面是利用喷发的岩石和矿物(在同一两座火山，埃特纳和基拉韦厄火山)，试图了解汞和它在化学上相似的“表亲”(金属，包括Cd，锌，铜)是如何冷却和结晶的。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，在结晶过程中，它们在熔体中的浓度不会有太大变化，但可能会通过“脱气”而略有变化。我们可以通过对真实岩石的小样本进行精确的(激光)测量来检验这一想法。

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.