EESA06H3 Lecture Notes - Lecture 11: Leachate, Cascadia Subduction Zone, Sodium Chloride
25 views15 pages
For unlimited access to Class Notes, a Class+ subscription is required.
3 hour Final multiple choices Exam: Wednesday April 25th 2012, Based on: Chapters 1 to 3, 11, 19, 20,
Lectures 10 and 11, 120 questions
Fig. 20.6 Rodinia at the top, everything is coming
together and then that breaks up. This is the beginning of the Wilson cycle. On the right hand side of the
third picture is Africa coming in which is the beginning of Pangea and that’s going to collide. So all the
actions is happening on the Eastern side of North America. Then the Atlantic opens and then all the
other geologic actions happen on the Western side of North America. How the diagram works?
An Urban World: The Age of Construction. Why do we need to know
how the world works or study environmental science? We need to apply this knowledge in the real
world to make the planet more habitable. We need to understand real world systems, how they work
and how we are changing whether it’s climate, ocean circulation, soil lost, etc. The really big one is that
we are in an age of construction. The planet is turning into an urban planet. Everyone is living in cities.
Almost 80 % of people are living in cities. Those cities create what we call an urban shadow that reaches
far beyond the cities in terms of to supply water, energy resources, to the urban areas and then we got
to get rid of waste products. Many of our environmental problems worldwide are simply due to the
growth of these enormous super cities. Super cities – any city more than 10 million people. The very
influence of this allows these cities to grow such as productivity to harbors, rivers, lands, are often a
result of geology. They are all often in plate tectonic areas that are active. The vast majority of super
cities are all affected to volcanoes. A lot of them are in the Pacific rims and so the risk from natural
hazard is increasing dramatically. There’s more volcanic eruption, there’s more earthquakes, and you
have these fixed population sitting there in one of the active areas. More people are killed by
earthquakes than by disease.
Some of the most rapid environmental changes that we know that are on the planet are happening on
the margins of continental areas.
Welcome to the Anthropocene: ‘The Epoche of Man’. There is a new
geologic period of people that introduces; it’s called the anthropocene which is really our age which
means the Epoche of man. If you were to define a period which is now dominated by our influences on
the environment, we shift more sediment every year than rivers. We are changing the chemistry of the
atmosphere. When would you say that actually began? When do you think the influences of man and
woman actually began to have a profound effect on the environment? The Industrial Revolution which is
the late 1870s where the invention of the steam engine was created which is the real beginning of the
Anthropocene. On the picture, this is North Toronto and we now have a built landscape. This is made
out of fore. You are dealing with material called fill which is all the material of waste material we
brought into urban areas to level areas for new construction.
To Meet Challenges of Change....
e.g., Urban sprawl, Managing/protecting water resources and watersheds, waste (nuclear, municipal
industrial etc), Remediation of contaminated sites, Radon gas, Earthquakes, landslides & tsunamis,
Mitigation of climate warming effects, Environmental impact of resource extraction and energy supplies:
oil sands, coal etc. Environmental policy and planning.... We need environmental scientists
We live in a very rapidly changing environment. These are some of the issues that environmental
scientist are interested in. Urban sprawls – what we call a hardening of watersheds. You are replacing
natural soils which allows are water to infiltrate. The hardening of watersheds is by building buildings
with roofs, with ash build roads, so your changing what we call a hydrology = (The way in which the
watersheds functions). This is the emerging issue both in terms of water quantity, there isn’t enough in
Southern areas and water quality even if there is, and the effects of urban development industrialization
have been to contaminate huge volumes of water.
We got to dispose the waste. Nuclear waste, there’s actually a search right now in Ontario for a deep
repository (storage facility), for mid – to lower radioactive waste. We got to store waste for a million
years. The Great Lakes didn’t exist 2 million years ago by recent ice ages. These huge basins are very
young. If you’re trying to look a million years into the future, there’s going to be profound changes into
the landscape because we are probably going to have other ice ages between now and then.
Municipal waste – this is the waste that we put out on the curve side every week, household waste.
There is not enough space to put it and what we have done in the past is simply fill up holes on the
ground, old gravel pits, burry this stuff. This is not very good because this just sits there and produces
contaminated water what we call leachate. This leachate is contaminated water that goes down into the
ground water and this is why we don’t drink ground water in urban areas. We get our drinking water out
of the lake. The ground water is no longer potable which means water that can be safely consumed.
Industrial waste. If you are familiar with the ongoing waterfront down in Toronto, the problems down
there is due to mainly the fact is that there are old industrial sites with the contaminants lying in the
ground. We don’t know where they are but they have to be cleaned up which is very expensive. These
different chemical type each requires a different cleanup process. There are some sites down there
where there are possibly a hundred different chemicals reflecting changing industrial use of the sight.
There’s a growing area of environmental science called for remediation. It’s a major part of the
emphasis on mars environmental science because we can’t keep consuming agricultural land. We got to
reuse old urban area which has been occupied for hundreds of years. We got to learn how to investigate
these sites. This is where new techniques come in. They do a lot of drilling, they are like dentists except
they drill deeper holes to find out what’s down there but they can’t do that on contaminated sites
because the dangerous is they might discover any sort of waste down there, pipelines, tanks, etc.
Remotely exploring the geology of different sites to get an idea of what’s down there first before we
start proving. There’s a whole new science in that which is now starting.
How do we deal with contaminants? Do we deal with them on sites? Do we deal with them on the
ground or do we have to extract them from the ground and deal with them on the side? Do we have to
have a soil exchange program where all that contaminated material is taken away, it’s cleaned up and
then clean fill is brought back?
Radon gas is radioactive and its release from rocks from granites which contains uranium and uranium
breaks down into lead. In the process, radon is created and it collects in basements, but it’s a big
problem where you have granite. Our granites are in the Shield which is a hundred km below us. There is
radon seeping in along faults, fractures. It’s an emerging problem but not a very huge problem.
Natural hazards – Earthquakes, landslides, tsunamis.
Mitigation of climate warming effects is a big area now. The biggest effect of climate change in Canada is
not in the urban areas because we live inside, but the biggest impact is in the North. Permafrost –