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for other valuable ores
-
copper, gold, diamonds,
lead and zinc
-
has similar deleterious impacts
on wetland habitats (see Fig. 1-15).
Mining is now strictly regulated for safety and
environmental reasons in most developed coun-
tries. However, mining remains a “wild west”
activity in many developing and poorly devel-
oped countries of the world. In order to fuel its
rapid industrial growth, China has become the
world's leader in coal use, overtaking the United
States, European Union and Japan combined,
and India is following close behind (Bradsher
and Barboza 2006). Chinese coal mining has
increased dramatically in recent years with little
attention to environmental consequences, which
has led to increased wasteland and desertii ca-
tion, declines in ground water, land subsidence,
and salt-water intrusion in coastal regions (Yang
2007). Untreated drainage from mines and tail-
ings has greatly polluted surface and ground
water.
Most upper Carboniferous coal in eastern
North America has high sulfur (pyrite) content.
Sulfur dioxide gas emitted from burning such
coal is converted by a catalyst, such as NO
2
, into
sulfuric acid (H
2
SO
2
), which is a major compo-
nent of acid rain. Acid rain and snow across
southeastern Canada and the eastern United
States has caused acidii cation of many thou-
sands of lakes and streams, particularly in
regions with crystalline bedrock and soft water
that have little buffering capacity, such as the
Adirondack Mountains and northern Appalachi-
ans (US Environmental Protection Agency 2007).
Acid deposition on soils releases aluminium,
and both low pH and aluminium are directly
toxic for many i sh species, few of which can
survive a pH less than 5. Because of this problem,
low-sulfur coal and lignite from western Canada
and the United States are now preferred for
electric power plants.
Acid precipitation is also a serious problem
in northwestern Europe, where many historic
buildings have been damaged (Fig. 10-13). The
disappearance of
Sphagnum
mosses as a conse-
quence of atmospheric pollution was described
more than two centuries ago in Great Britain
(Paal et al. 2009), and high concentration of SO
2
is the main cause for
Sphagnum
decline in other
industrial areas. Bog experiments in Scotland
demonstrated that deposition of sulfate from
acid rain leads to a decline in methane emission,
presumably because sulfate-reducing bacteria
outcompete methanogens (Gauci, Dise and
Fowler 2002).
Strict pollution controls on coal-burning
power plants and automobile exhaust have
helped to reduce the acid rain problem in North
America and western Europe in recent years, but
uncontrolled emissions continue in many other
parts of the world (Marquardt 2012). In China, for
example, massive air pollution from coal burning
has caused serious issues for human health, and
widespread acid rain has severely damaged rivers
and related wetland habitats (Yang 2007).
10.3.3 Estonian oil shale
Burning oil shale in northeastern Estonia heavily
damaged nearby bogs through deposition of
calcium-rich l y ash (Karofeld 1996; Paal et al.
2009). The Ordovician oil shale is extracted
from several large open-pit and underground
mines and fuels power plants and chemical fac-
tories that represent signii cant parts of the Esto-
nian economy. During Soviet times, industrial
development was emphasized, and large power
plants began operating in the 1950s and 60s
with uncontrolled emission of l y ash.
Sphag-
num
mosses began to disappear from nearby
bogs in the 1970s due to a combination of
increased pH and calcium in bog water and
upper layers of peat. In the most polluted bogs,
pH values rose above 5 to
>
6, compared with
pH
4 in unaffected bogs.
Sphagnum
mosses
completely disappeared from some bogs, and
Scots pine (
Pinus sylvestris
) showed increased
radial growth. As
Sphagnum
mosses died out,
bogs lost their buffering ability, and a rapid shift
took place in which other bryophyte species
and vascular plants became established on less
acidic to near-neutral soils with higher nutrient
levels. In effect, the oligotrophic bogs under-
went a conversion into mesotrophic fens.
Since the collapse of the Soviet empire and
Estonian independence, atmospheric pollution
from burning oil shale has been reduced
drastically because of decreased production of
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