31 / 44
31
MERCURY – TIME TO ACT
Mercury residues from mining and industrial processing, as
well as mercury in waste, have resulted in a large number of
contaminated sites all over the world. Polluted soil can con-
tain as much as 400 grammes of mercury per hectare, as
measured at a Venezuelan gold mining site (Garcia-Sanchez
et
al
., 2006). Most mercury contamination sites are concentrated
in the industrial areas of North America, Europe and Asia; and
in sub-Saharan Africa and South America. In contrast to Eu-
rope and North America, the number and extent of mercury-
contaminated sites in other parts of the world is increasing
because of the rising use of mercury (Kocman
et al
., 2011).
Safe storage of mercury-containing waste and rehabilitation
of various hotspots is needed.
Air pollution control technologies in industrial facilities re-
move mercury that would otherwise be emitted to the air, but
there is little information about the ultimate fate of the mercu-
ry captured in this way or about how the mercury-containing
wastes are subsequently disposed of. However, it is likely that
these control technologies will reduce the amount of mercury
that is transported globally by air. But the mercury captured
by filters will be disposed of in the area where it originated.
While the atmosphere responds relatively quickly to changes
in mercury emissions, the large reservoirs of mercury in soils
and oceans mean that there will be a long time lag (in the or-
der of tens of decades) before reductions in mercury inputs
are reflected in depleted concentrations in these media and in
the wildlife taking up mercury from them.
Artisanal and small-
scale gold mining and
coal burning are the
largest anthropogenic
sourcesof emissions.