Mercury-Contaminated Industrial and Mining Sites
in North America: an Overview with Selected Case
Studies 1
R.R. TURNER and G.R. SOUTHWORTH
Mercury (Hg) has been used in highly diverse industrial and mining applications in North America,
often with both intentional and unintentional releases to environmental media. While industries
producing chlorine and caustic soda using the Hg-cell process, and the earlier extensive use of
mercury in the mining of noble elements, have historically been among the most significant sources of
such releases, other industries, including the US government, have also contributed substantially.
Significant curtailment of intentional releases to aquatic systems in North America began about 1970,
but it has only been recently that the legacies of past, and in some cases unrecognized continuing
releases have begun to be addressed at many sites. This chapter briefly summarizes typical
contamination scenarios at a variety of industrial sites and provides more detailed reviews of selected
case studies which illustrate some remarkable consistencies among such sites.
1
Introduction
Mercury has historically found hundreds of industrial uses in North America
(Jasinski 1995). However, hardly an industry which used mercury in one way or
another has escaped experiencing releases into the environment. Some of the
same unique physical (e.g., density, liquid state at ambient temperature,
volatility) and chemical properties (e.g., ease of reduction) of mercury which
make it so useful in industrial applications have also made it difficult to contain
and to recover from the environment. Opportunities for environmental releases
of mercury are much greater than for other metals. Even when mercury is used
initially in one physical or chemical form, it can be readily transformed to other
forms which can more easily escape from industrial processes. For example, in
the production of chlorine and caustic soda by electrolysis of brine, mercury in
the liquid metal form is used both as an electrode and as a "solvent", or
amalgamator, for sodium. Theoretically, at least, there should be little consumption of mercury in the process other than small losses which leave the facility in
the products. In fact, prior to about 1970, such facilities typically had to replace 5
to 10% of their mercury stocks annually to sustain production rates and the
"average" facility could not account for 50% of the annual losses (EPA 1975). In
addition to the obvious volatile losses of the metal from the process, mercury was
lThis work was partially sponsored by the Oak Ridge Y-12 Plant Health, Safety, and Environment
Division. The Y-12 Plant is managed by Lockheed Martin Energy Systems, Inc. under contract DEAC05-840R21400 with the US Dept. of Energy
Environmental Science
Mercury Contaminated Sites (ed. by R. Ebinghaus et al.)
© Springer-Verlag Berlin Heidelberg 1999
in North America: an Overview with Selected Case
Studies 1
R.R. TURNER and G.R. SOUTHWORTH
Mercury (Hg) has been used in highly diverse industrial and mining applications in North America,
often with both intentional and unintentional releases to environmental media. While industries
producing chlorine and caustic soda using the Hg-cell process, and the earlier extensive use of
mercury in the mining of noble elements, have historically been among the most significant sources of
such releases, other industries, including the US government, have also contributed substantially.
Significant curtailment of intentional releases to aquatic systems in North America began about 1970,
but it has only been recently that the legacies of past, and in some cases unrecognized continuing
releases have begun to be addressed at many sites. This chapter briefly summarizes typical
contamination scenarios at a variety of industrial sites and provides more detailed reviews of selected
case studies which illustrate some remarkable consistencies among such sites.
1
Introduction
Mercury has historically found hundreds of industrial uses in North America
(Jasinski 1995). However, hardly an industry which used mercury in one way or
another has escaped experiencing releases into the environment. Some of the
same unique physical (e.g., density, liquid state at ambient temperature,
volatility) and chemical properties (e.g., ease of reduction) of mercury which
make it so useful in industrial applications have also made it difficult to contain
and to recover from the environment. Opportunities for environmental releases
of mercury are much greater than for other metals. Even when mercury is used
initially in one physical or chemical form, it can be readily transformed to other
forms which can more easily escape from industrial processes. For example, in
the production of chlorine and caustic soda by electrolysis of brine, mercury in
the liquid metal form is used both as an electrode and as a "solvent", or
amalgamator, for sodium. Theoretically, at least, there should be little consumption of mercury in the process other than small losses which leave the facility in
the products. In fact, prior to about 1970, such facilities typically had to replace 5
to 10% of their mercury stocks annually to sustain production rates and the
"average" facility could not account for 50% of the annual losses (EPA 1975). In
addition to the obvious volatile losses of the metal from the process, mercury was
lThis work was partially sponsored by the Oak Ridge Y-12 Plant Health, Safety, and Environment
Division. The Y-12 Plant is managed by Lockheed Martin Energy Systems, Inc. under contract DEAC05-840R21400 with the US Dept. of Energy
Environmental Science
Mercury Contaminated Sites (ed. by R. Ebinghaus et al.)
© Springer-Verlag Berlin Heidelberg 1999