Due to its inherent characteristics, mercury contamination from gold mining is a major environmental problem compared to past mercury contamination from industrial point sources. The worsening of social-economical conditions and increasing gold prices in the late 1970s resulted in a new rush for gold by individual entrepreneurs for whom Hg amalgamation is a cheap and easily carried out operation. Even after the present-day mining areas are exhausted, the mercury left behind will remain part of the biochemical cycle of the tropical forest. This book reviews the current information on mercury from gold mining, its cycling in the environment and its long-term ecotoxicological impact. The book is illustrated with numerous diagrams and photographs.

Inhalt

1 The Use of Mercury Amalgamation in Gold and Silver Mining.- 1.1 Historical Background.- 1.2 Present-Day Worldwide Utilization of Mercury Amalgamation.- 1.3 Present-Day Amalgamation Mining Techniques.- 2 Estimating Losses of Mercury to the Environment.- 2.1 Emissions Factors.- 2.2 Mercury Emissions from Historical Gold and Silver Mining.- 2.3 The Second Gold Rush in the South.- 3 Mercury in the Atmosphere.- 3.1 Characteristics of Mercury Emission to the Atmosphere.- 3.1.1 Active Mercury Vaporization: Burning of Amalgam.- 3.1.2 Passive Mercury Vaporization: Degassing from Contaminated Soils, Waters and Tailings.- 3.2 Mercury Concentrations in Air of Urban and Rural Areas.- 3.3 Chemical Forms, Reactivity and Fate of Hg in the Atmosphere.- 3.4 Impacted Areas Through the Atmospheric Transport Pathway.- 3.4.1 Soils.- 3.4.2 Lakes.- 4 Mercury in Tropical Aquatic and Terrestrial Systems.- 4.1 Characteristics of Mercury Emissions to the Aquatic Environment.- 4.2 Leaching from Tailings.- 4.2.1 Mercury Distribution in Gold Mining Tailings.- 4.2.2 Mercury Export from Tailings to Adjacent Aquatic Systems.- 4.3 Rivers.- 4.3.1 River Systems in Tropical Areas.- 4.3.2 Mercury and Its Associations in River Sediments.- 4.3.3 Hydrological Effects on Hg Dispersion.- 4.3.4 Dispersion of Mercury in River Systems.- 4.4 Tropical Reservoirs.- 4.4.1 Atmospheric Inputs.- 4.4.2 Fluvial Inputs.- 4.4.3 Mercury Cycling in Artificial Tropical Reservoirs.- 4.5 Mercury Methylation.- 5 Mercury in Biota.- 5.1 Terrestrial Vegetation.- 5.2 Aquatic Macrophytes.- 5.3 Animals (Excluding Fish).- 5.4 Fish.- 5.4.1 Mercury Concentrations and Distribution in Fish.- 5.4.2 Methyl-Mercury in Fish from Gold Mining Areas.- 5.4.3 Fish Response Changes in Hg Environmental Concentrations.- 5.5 The Atmospheric Link in Fish Mercury Content of Fish.- 6 Mercury Contamination of Humans in Gold and Silver Mining Areas.- 6.1 Exposure Characteristics to Human Groups.- 6.2 Mercury Concentrations in Humans from Occupational Exposure.- 6.3 Mercury Concentrations in Humans Due to Environmental Exposure.- 6.3.1 Mercury Concentrations in Human Blood.- 6.3.2 Mercury Concentrations in Human Hair.- 7 Perspectives on the Temporal Development of Mercury Inputs into the Environment.- 7.1 Global Inputs.- 7.2 The Decrease in Mercury Inputs from Industrial Point Sources.- 7.3 Temporal Development in Gold-Mining Regions: The Second Gold Rush and Before.- 8 Summary and Outlook.- References.