Acid Deposition
Impact on Ecosystems
• The study of environmental chemistry
involves more than just the detection of
substances.
• Scientists who study the environment conduct
investigations to determine whether there is
evidence of change in the environment.
• Predictions currently being made by scientists
rely upon the knowledge that comes from
careful study of interactions within the
environment.
• Since the environment is the one thing that all
organisms share, research is necessary to
understand its ability to cope with stress from
pollution.
Relationship between Two Variables
 Direct Variation:
 A relationship between two related
variables where an increase in the
magnitude of one variable results in
an increase in the magnitude of the
related variable
 Inverse Variation:
 A relationship between two related
variables where an increase in the
magnitude of one variable results in
a decrease in the magnitude of the
related variable

No Relationship:
 a situation where no
recognizable pattern is
demonstrated between two
variables
Example
Higher levels of sulfates and
nitrates in rainwater result in a
higher concentration of
hydronium ions in the water
(direct variation) and, thus,
results in a lower pH (inverse
variation).
•
Wind Patterns
• Remember to consider what influences
weather patterns might have on acid
deposition.
• Wind patterns like the jet stream provide a
way for acid deposition to be transported.
• The predictability of wind patterns provides a
way to trace the path of acid deposition back
to its source.
Define the term jet stream. State the
general direction of the jet stream.
The jet stream is an air current located at the
boundary between major air masses (pressure
systems).
The location of the pressure systems
determines the direction of this air current.
 Generally, the jet stream moves from west to
east across North America.
Explain the effect the jet stream has on
weather and climate in western Canada.
 The position of the jet stream indicates the
main direction of the winds across Alberta
(from west to east).
The position also influences weather because
low-pressure systems (which usually bring
moisture) track along the jet stream.
 Winds are directed toward the jet stream.
 Cold air from the north is drawn toward the
jet stream, whereas warm air from the Pacific
Ocean is drawn toward the jet stream from
the south.
 When the position of the jet stream moves
downward, more of Alberta is subject to
colder air.
During the winter months, this causes
extremely cold temperatures
Comment on the statement, “Wind patterns in
Canada and Alberta are always the same.”
The position of the jet stream is
quite variable, influencing weather
across Canada.
In general, however, winds move
eastward across North America.
Alberta generally has winds that
track eastward.
• Does Canada’s position in the
northern hemisphere ensure
that air transported by
currents, such as the jet
stream, are relatively clean
and unpolluted?
• North America has regions that are densely
populated and industrialized.
• In general, the jet stream often dips southward
around the Great Lakes region and tracks over
the northeastern US; then it tracks in a
northeasterly direction toward Canada.
• As the northeastern US is heavily populated and
industrialized, emissions from this area are drawn
toward Ontario, Quebec, and the Atlantic
provinces.
• The eastward direction of the winds across
western Canada draws emissions originating in
Alberta toward Saskatchewan.
 Effects of Acid Deposition
on the Environment and
Ecosystems
Acid Deposition
 Effects the pH of water
 Caused by hydronium ions being
formed during a reaction of acids
and water.
Carbonate Ions
• CO3 are a naturally occurring base present in
many bodies of water and in the soil.
• In Alberta, the pH of most lakes is above 7 and
can be as high as 8.3
• The slightly alkaline pH of the lake water is
due to the presence of dissociated carbonate
ions that enter the water from dissolving
minerals, such as calcium carbonate and
magnesium carbonate present in limestone.
 oceans were made up of calcium
carbonate, CaCO3(s).
Over time, the layers of calcium
carbonate formed into limestone—a
type of sedimentary rock.
As limestone undergoes erosion,
small crystals of calcium carbonate
present in the limestone form
particles in the soil.
The carbonate ions, acting as acceptors for hydrogen
ions, convert hydronium ions into water molecules,
thereby neutralizing the acid.
Only a small percentage of soils
in Canada have a high potential
for neutralizing acid deposition.
Much of the soil within the
province of Alberta has a high
potential, mainly due to the
presence of carbonate.

Student Hand-out
Answers
• 29. No, there is a range of abilities to neutralize acid
deposition across Canada.
• 30. The highest potential for reducing acid deposition
occurs in Alberta (except in the extreme north), the
• southern half of Saskatchewan, the southern half of
Manitoba, part of northern Ontario, and Quebec.
• 31. Yes, there is a correlation between rock type
(sedimentary) and higher potential to reduce acid
input.
• 32. Regions in Canada with the least ability to reduce
acid deposition include the coastal mountains of British
Columbia, Districts of Mackenzie and Nunavut,
southern Ontario, Quebec, most of Newfoundland and
Labrador (except the west coast of Labrador), Nova
Scotia, and parts of New Brunswick and Prince Edward
Island.
• 33. Yes, rock types in more sensitive areas tend to be
volcanic, intrusive, or metamorphic.
• 34. No, southern Alberta has a high potential, whereas
northern Alberta has moderate potential and, in a few
extreme northern locations, low acid-reducing
potential.
• 35. Answers will vary. In areas with a high neutralizing capacity,
pH should remain constant. In regions with a low neutralizing
potential, there may be a lowering of soil and lake-water pH.
• 36. a. Quebec, 82%
• b. Alberta, 6%
• c. Yes, Alberta has soils that are, for the most part, highly
tolerant to acid inputs and few lakes that are sensitive. Quebec
has few regions with soils that are highly tolerant and has a
very high percentage of sensitive lakes.
• d. Composition of soils and bedrock provide the ability to
neutralize acid deposition. If substances are not present, then
sensitivity to acid deposition will increase.