Managing surplus mercury involves collection, stabilization and safe disposal to isolate it from the biosphere. Stabilizing mercury offers several benefits: technology is available on an industrial scale, there is no risk of liquid spillage, vapour pres- sure is below occupational safety limits, and mercury con- centrations in leachates are below the threshold for disposal. Beyond that, the lower commercial value of the stabilized mercury reduces the risk of theft, and disposal after stabiliza- tion by binding with sulphur is possible. Several stabilization

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technologies exist: chemical transformation into a more sta- ble, less mobile chemical compound; micro-encapsulation, the embedding of particles in an impermeable matrix such as cement; and macro-encapsulation, the covering of waste material with an impermeable material, for example poly- ethylene. The fact that stabilized mercury is non-toxic signifi- cantly helps the search for suitable storage sites. Unlike liquid mercury, the stabilized form is suitable for storage in landfills and underground.