ENVIRONMENTAL IMPACTS OF METAL ORE MINING AND PROCESSING - A REVIEW

The impact of mining and smelting of metal ores on environmental quali ty is described. Mines produce large amounts of waste because the ore is only a small fraction of the total volume of the mined material. In the metal industry, production of Cu, Pb, and Zn causes the greatest degradation of the environment. Copper mining produces extensive mine wastes and tailings and Cu smelting emits approximately 0.11 Mg of S p er Mg of Cu produced in the USA. Zinc and ph smelters release large qu antities of Cd and Pb into the environment. Metal smelting and refinin g produce gaseous (CO2, SO2, NOx, etc.) and particulate matter emissio ns, sewage waters, and solid wastes. Soil contamination with trace met als is considered a serious problem related to smelting; however, mini ng and smelting are not main sources of global metal input into soils. Other sources like discarded manufactured products, coal ash, agricul ture, and transportation take a lead. Smelters are the main sources of atmospheric emissions of As, Cu, Cd, Sb, and Zn on a global scale and they contribute substantially to the overall emissions of Cr, Pb, Se, and Ni. A quantitative evaluation of the environmental health effects of mining and smelting is difficult because of the complexity of fact ors involved and lack of consistent methodology. Nevertheless, the cas e studies described indicate that negative health effects could arise from Pb mining and smelting. Risk assessment revealed that food chain contamination by Cd from soils contaminated by smelting is very unlike ly under the western diet.