Myanmar has large geological resources for exploration and extraction of metals and ores, especially copper, lead, silver, tin, tungsten, zinc, nickel, and gold. The different mining activities in Myanmar have a range of potential effects on human health and the environment. Depending on which minerals are being extracted and how they are extracted, environmental consequences can be an issue of local, regional, or global concern. An example is small-scale gold mining where mercury often is used in the extraction process. Mercury has potentially severe local impacts for the people involved in the use of the element, due to the heating of liquid mercury that evaporates. Mercury can also influence the local aquatic environment, and the food sources therein. Other examples on environmental effects from mining activities include erosion and sedimentation due to excavating of soil and rock, releases of other substances as cyanide and sulphuric acid, and deforestation.