Environmental Engineering Reference
In-Depth Information
grains of quartz sand held together by 10 percent of a tarry hydrocarbon
material called bitumen that can be extracted and liquefi ed using steam.
The tar was once liquid and able to fl ow, but the volatile material has
evaporated over the eons, leaving the tarry residue that requires an
expensive refi ning process to be converted into syncrude (synthetic crude
oil). About 10 percent of the Canadian tar sands crop out at the surface
and can be strip-mined, much like some Appalachian coal deposits; 90
percent are below ground.
Converting the tar into syncrude requires more energy and water than
producing conventional oil, and the refi ning process produces lots of
environmental damage: sulfur, acid rain, and 10 to 15 percent more
greenhouse gases than the refi ning of conventional oil. Greenhouse emis-
sions from tar sand mining are predicted to triple by 2020.
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Mining tar sands generates enormous volumes of liquid waste that
are stored in toxic lakes in the sparsely inhabited area of northern
Alberta where the tar sands occur.
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The sludge seeps into the rivers and
groundwater systems. One of the mining companies admitted that its
Tar Island Pond leaks approximately 423,000 gallons of toxic fl uid into
the Athabasca River every day. The tailings ponds are growing con-
stantly and in February 2008 covered more than 31 square miles. Can-
ada's National Energy Board has warned that current production trends
indicate that the volume of fi ne tailings ponds produced by the two major
mining companies alone will exceed 260 billion gallons by 2020. Tailings
dikes have major failures every six months, on average, worldwide. The
largest dam in the world is a toxic sludge reservoir behind one of the
Syncrude company's earthen dikes. It is visible from space.
Toxic materials from tar sand activities are not restricted to the lakes.
A recent study commissioned by a health organization in Alberta identi-
fi ed high levels of carcinogens and toxic substances in fi sh, water, and
sediment downstream from tar sands projects. Mercury levels in sedi-
ments are as much as double historical means, and arsenic levels are
seventeen to thirty-three times the acceptable levels in moose meat from
the region. In a Native American community near the tar sands project,
the resident doctor has been concerned about the high numbers of nor-
mally rare types of cancers in the town. Environmental concerns related
to tar sand mining have not been the top priority in Alberta or in the
nation's capital. Tens of thousands of new jobs in resource extraction
have been generated by exploitation of the tar sands, and in 2006 every
Albertan received a $340 check from the government because of the fi scal
surplus generated by the oil from tar sands.
