Mercury Contamination from New World Gold
and Silver Mine Tailings
L.D. LACERDA and W. SALOMONS
1
Introduction
The input of mercury by industrial point sources into the environment has
decreased drastically in both developed and developing countries. The remaining
issues, in particular in temperate climates, are the accumulated levels of mercury
in hot spots like industrial sites and contaminated soils and sediments. The
appropriate technology for cleanup of hot spots is, in principle, available (see the
various chapters in this Vol.). Furthermore, new technologies are available that
completely exclude or limit the use of mercury.
The issue in the developing countries is quite different. Although emissions for
point sources have decreased here also, the "diffuse" use of mercury in gold
mining has increased over the past years and is likely to increase in the future. Its
attractiveness lies in being a reliable and cheap technology easy to operate on the
individual scale. Furthermore, mercury is used by large groups of individuals in
many widely dispersed and often remote areas. Controlling this type of use is
more difficult compared with controlling mercury discharges from (few)
industrial point sources. This type of pollution abatement has a strong
socioeconomic dimension. Therefore, notwithstanding the recent regulations
making the acquisition and use of Hg in many countries more difficult, this type
of technology will only be limited by the exhaustion of appropriate gold and
silver deposits or by a drastic decrease in gold prices. Both alternatives are
unlikely to occur in the next 50 years, and new prospecting areas are expected to
be opened in particular in northern South America and Southeast Asia. Thus the
issues with mercury-contaminated tailings sites will remain, and their area will
increase in the foreseeable future. This chapter gives an overview of the available
knowledge on the behavior and impact of mercury in tailings from the "first" and
"second" gold rushes.
2
Past and Present Use of Mercury in Gold and Silver Mining
Mercury amalgamation was the major gold and silver mining technique until the
beginning of this century. This technique is believed to have consumed over
Environmental Science
Mercury Contaminated Sites (ed. by R. Ebinghaus et aLl
© Springer-Verlag Berlin Heidelberg [999
and Silver Mine Tailings
L.D. LACERDA and W. SALOMONS
1
Introduction
The input of mercury by industrial point sources into the environment has
decreased drastically in both developed and developing countries. The remaining
issues, in particular in temperate climates, are the accumulated levels of mercury
in hot spots like industrial sites and contaminated soils and sediments. The
appropriate technology for cleanup of hot spots is, in principle, available (see the
various chapters in this Vol.). Furthermore, new technologies are available that
completely exclude or limit the use of mercury.
The issue in the developing countries is quite different. Although emissions for
point sources have decreased here also, the "diffuse" use of mercury in gold
mining has increased over the past years and is likely to increase in the future. Its
attractiveness lies in being a reliable and cheap technology easy to operate on the
individual scale. Furthermore, mercury is used by large groups of individuals in
many widely dispersed and often remote areas. Controlling this type of use is
more difficult compared with controlling mercury discharges from (few)
industrial point sources. This type of pollution abatement has a strong
socioeconomic dimension. Therefore, notwithstanding the recent regulations
making the acquisition and use of Hg in many countries more difficult, this type
of technology will only be limited by the exhaustion of appropriate gold and
silver deposits or by a drastic decrease in gold prices. Both alternatives are
unlikely to occur in the next 50 years, and new prospecting areas are expected to
be opened in particular in northern South America and Southeast Asia. Thus the
issues with mercury-contaminated tailings sites will remain, and their area will
increase in the foreseeable future. This chapter gives an overview of the available
knowledge on the behavior and impact of mercury in tailings from the "first" and
"second" gold rushes.
2
Past and Present Use of Mercury in Gold and Silver Mining
Mercury amalgamation was the major gold and silver mining technique until the
beginning of this century. This technique is believed to have consumed over
Environmental Science
Mercury Contaminated Sites (ed. by R. Ebinghaus et aLl
© Springer-Verlag Berlin Heidelberg [999