The materials flow of mercury in the economies of the United States and the world

Although natural sources of mercury exist in the environment,
measured data and modeling results indicate that the
amount of mercury released into the biosphere has increased
since the beginning of the industrial age. Mercury is naturally
distributed in the air, water, and soil in minute amounts, and can
be mobile within and between these media. Because of these
properties and the subsequent impacts on human health, mercury
was selected for an initial materials flow study, focusing on the
United States in 1990.
This study was initiated to provide a current domestic and
international analysis. As part of an increased emphasis on materials
flow, this report researched changes and identified the associated
trends in mercury flows; it also updates statistics through
1996. In addition to domestic flows, the report includes an international
section, because all primary mercury-producing mines
are currently foreign, 86 percent of the mercury cell sector of the
worldwide chlor-alkali industry is outside the United States, there
is a large international mercury trade (1,395 t
1
in 1996), and environmental
regulations are not uniform or similarly enforced from
country to country.
Environmental concerns have brought about numerous regulations
that have dramatically decreased both the use and the
production of mercury since the late 1980?s. Our study indicates
that this trend is likely to continue into the future, as the world
eliminates the large mercury inventories that have been stockpiled
to support prior industrial processes and products.