The Circulation of Mercury in the Italian economy

Mercury has been a metal with a very significant role in many production cycles (such as chlor-alkali industry), and, despite its toxicity, it continues to have a great importance. On the contrary, the content of mercury in many common commodities (batteries, dental amalgams, lighting, electrical and electronics equipment and others) is very high. This exposes the population to enormous risks due to the chemical and physical characteristics of this metal. Mercury could be considered a global pollutant: it can be easily transported over great distances by air flows and its residence time in the atmosphere is about one year: this is a long time during which mercury can circulate all around the world several times. The reason of this is the chemical feature of the mercury in atmosphere (more than 90% is represented by elemental gaseous form Hg0, slightly soluble and relatively inert). In addition, after its oxidation to divalent mercury HgII, part of this metal enters the soil and surface water. From here, a low part of it can be reduced to the volatile elemental form that is emitted into the atmosphere once again (the so-called re-emission). The third atmospheric form of mercury is the Hgpart, in which the metal is associated to particulate, often emitted by combustion industries and power plants. The entire bio-geo-chemical cycle of mercury demonstrates its danger. Despite of enormous damages produced by this metal and the many legislative measures to limit the mercury content in several goods, the direct emissions and the indirect ones (due to fossil fuel combustion) recorded in some countries, as China and India, are increasing. The aim of this note is to identify the flows of this metal related to its circulation in Italy, in order to describe the amount of mercury contained in commodities and its use in industry.