EESA10H3 Lecture Notes - Lecture 3: Water Scarcity, Municipal Solid Waste, Bioaccumulation
24 May 2018
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Department
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Human Health and the Environment
EESA10- Lecture 3- Water
71% of planet earth is covered by water but most of it is salt water, which means that it is not
readily available as drinking water (so it must be treated). Most living organisms prefer fresh
water rather than salty water.
Water is important for supporting life on earth but it is also important to humans because it is a
carrier of pollutants and sediments which can affect human health if the water becomes
contaminated.
Two important world issues concerning water is the quantity of water and quality of water.
1. Quantity of Water:
a. How much freshwater
is available
i. Only 2.6% of all water on the planet is freshwater and a portion of it is
found in ice caps while another portion of fresh water can be captured
from groundwater.
ii. Lakes are a readily available source of freshwater, but lakes only make up
0.007% of water sources on the planet.
b. Available sources of freshwater is unevenly distributed across the planet
i. Water stress: If the area has less than 1700 cubic meters of water
/meters/person
a. North Africa
b. Large portion of Asia
c. Middle East
d. Southwestern part of US
e. Parts of Australia
f. Canada has access to lots of quality freshwater
ii. Water Scarcity: If the area has less than 1000 cubic meters of
water/years/person
Human Health and the Environment
c. Withdrawal: the total amount of water that is taken from freshwater sources
such as rivers, lakes, or aquifers.
i. Toronto’s source of freshwater is Lake Ontario and is purified, chlorinated
before it enters the city.
ii. Agricultural uses for water results in the largest withdrawal rates
(especially in arid climates).
d. The availability of water can impact the way humans use water in their daily life
whether it is how and how often they shower or water plants, lawn, cleaning
house or car, etc.
i. Hydrological Poverty: People who live in areas of water stress or water
scarcity live in hydrological poverty regardless of their income.
2. Quality of Water:
a. Naturally pure water means it has some salts: including calcium carbonate,
sodium,
b. In urban areas, freshwater comes from surface water which is found in rivers,
lakes, or springs, but in rural areas, freshwater comes from groundwater which is
taken from wells.
i. Aquifers: Sources of groundwater. It is rock, gravel or sand that is
saturated with water.
a. Confined Aquifers: (Artesian wells) An impermeable layer
above and below the layer of groundwater and it is under
heavy pressure due to the two layers. The only access to
the water is by drilling through the impermeable layer.
b. Unconfined Aquifers: Water builds up because of an
impermeable layer of clay or rock or anything with a low
porosity. Generally these aquifers are more shallow and
closer to the surface and therefore easier to contaminate.
c. Potential sources of water contamination:
Document Summary
71% of planet earth is covered by water but most of it is salt water, which means that it is not readily available as drinking water (so it must be treated). Most living organisms prefer fresh water rather than salty water. Water is important for supporting life on earth but it is also important to humans because it is a carrier of pollutants and sediments which can affect human health if the water becomes contaminated. Two important world issues concerning water is the quantity of water and quality of water: quantity of water, how much freshwater is available i. Only 2. 6% of all water on the planet is freshwater and a portion of it is found in ice caps while another portion of fresh water can be captured from groundwater. ii. Lakes are a readily available source of freshwater, but lakes only make up.
