Technical Guidance Sheet (TGS) on normal levels of contaminants in English soils : mercury (Hg) : technical guidance sheet TGS07, July 2012

Mercury (Hg) is a metallic element present in small quantities (0.02 mg/kg) in the Earth’s crust. It is a highly toxic element, although its toxicity depends on its chemical form and the route of exposure. Several forms of Hg occur naturally in the environment, the most abundant natural forms of Hg being metallic Hg, cinnabar (HgS), Hg chloride (HgCl2), and methylmercury (CH3Hg). Mercury associates strongly with organic matter in soils and is relatively immobile and persistent. The major loss pathway from soils is as gaseous mercury.