Assessing background mercury deposition and emissions in Canada

汞普遍存在于全球环境中，包括加拿大北极等敏感的受体，由于其毒性、持久性以及在各种食物链中生物积累和生物放大的能力而受到关注。虽然一些汞是通过火山等自然来源释放到环境中的，但环境中存在的大部分汞可归因于化石燃料燃烧、废物焚烧和金属加工等人为来源。一旦汞被释放到大气中，它就会经历一个复杂的循环，包括转化、大气传输，最终沉积到陆地和水生表面。在有利的天气条件下，汞可以挥发回大气中，经历进一步的长距离迁移和沉积循环，从而使汞成为真正的全球污染物。

Mercury is ubiquitous in the global environment, including sensitive receptors such as the Canadian Arctic, and is of concern due to its toxicity, persistence and ability to bio-accumulate and bio-magnify in various food chains. While some mercury is released into the environment through natural sources such as volcanoes, most of the mercury present in the environment can be attributed to man-made sources such as fossil fuel combustion, waste incineration, and metal processing. Once the mercury is released into the atmosphere, it undergoes a complex cycle involving transformations, atmospheric transport, and eventual deposition to terrestrial and aquatic surfaces. Under favourable weather conditions, the mercury can volatilize back into the atmosphere to undergo further long range transport and deposition cycles, thus making mercury a truly global pollutant.