Acid rain is a broad term used to describe several ways that acids fall out of the atmosphere. Acid rain is a phenomenon that results from industrial activities where sulfuric and nitric acids are produced by the release of sulfuric oxides (SOx) and nitrogen oxides (NOx) into the atmosphere. This induces the acidification of inland waters which results in damage to aquatic ecosystems, including fish. Acid rain flows into streams, lakes, and marshes after falling on forests, fields, buildings, and roads. It also falls directly on aquatic habitats. Acid rain was first reported in Manchester, England, which was an important city during the Industrial Revolution. The term “acid rain” was first used by Robert Angus Smith in 1872.

1. A PRESENTATION
ON
ACID RAIN AND AQUATIC ORGANISMS
BY
UWAMOSE OSAIGBOKAN MARTINS
CHIEF LIBRARIAN
DEPARTMENT OF ANIMAL AND ENVIRONMENTAL BIOLOGY,
DELTA STATE UNIVERSITY, ABRAKA.
MARCH, 2014
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2. INTRODUCTION
Acid rain was first reported in Manchester, England, which was
an important city during the Industrial Revolution. The term
“acid rain” was first used by Robert Angus Smith in 1872. Acid
rain is a phenomenon that results from industrial activities
where sulfuric and nitric acids are produced by the release of
sulfuric oxides (SOx) and nitrogen oxides (NOx) into the
atmosphere. This induces the acidification of inland waters
which results in damage to aquatic ecosystems, including fish.
Acid rain flows into streams, lakes, and marshes after falling on
forests, fields, buildings, and roads. It also falls directly on
aquatic habitats. According to the US energy information
administration, CO2 emissions from Nigerian gas flaring was
about 42.71 million metric tonnes in 1980 but reduced to 34.38
million metric tonnes in 2002. 2

3. Fig. 1. CO2 Emissions from Nigerian Gas Flaring, 1980-2002
Source: US Energy Information Adminisrtation
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4. CAUSES
Acid rain occurs when sulphur dioxide and nitrogen oxides are
emitted into the atmosphere, which then undergo chemical
transformations and are absorbed by water droplets in
clouds. The droplets then fall to earth as rain, or snow. This
can increase the acidity of the soil, and affect the chemical
balance of lakes and streams. This sulphur and nitrogen
compounds which are the principal cause of acid rain arise
from human sources such as electricity generation, burning of
any fuel that contains sulfur and nitrogen
compounds, including public utilities, industrial
broilers, motor vehicles, and chemical plants. These gases can
be carried hundreds of miles in the atmosphere before they
are converted to acids and deposited (Satake et al., 1995).
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5. Fig. 2. Emissions of sulphur dioxide and nitrogen oxides
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6. Fig. 3. View of Agip gas flares at Ebocha, Rivers State, Nigeria.
Source: Google images
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7. MEASUREMENT OF ACID RAIN
Acid rain is measured using a scale called "pH." The term "pH"
was originally derived from the French term "pouvoir
hydrogène," which means "hydrogen power" in English. the
pH scales ranges from 1-14. The lower a substance's pH, the
more acidic it is. Normal rain is slightly acidic because carbon
dioxide dissolves into it, so it has a pH of about 5.5. Very high
(greater than 9.5) or very low (less than 4.5) pH values are
unsuitable for most aquatic organisms. Young fish and
immature stages of aquatic insects are extremely sensitive to
pH levels below 5 and may die at these low pH values. High
pH levels (9-14) can harm fish by denaturing cellular
membranes (Leivested and Muniz 1976).
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8. Fig. 4. A scientist testing pH levels of water.
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9. EFFECTS
Acid rain causes acidification of lakes and streams and
contributes to damage of trees at high elevations and many
sensitive forest soils. In addition, acid rain accelerates the
decay of building materials and paints, including irreplaceable
buildings, statues, and sculptures that are part of our nation's
cultural heritage. Acid deposition penetrates deeply into the
fabric of an ecosystem, changing the chemistry of the soil as
well as the chemistry of the streams and narrowing
sometimes to nothing, the space where certain plants and
animals can survive. Because there are so many changes, it
takes many years for ecosystems to recover from acid
deposition, even after emissions are reduced and the rain
becomes normal again. 9

10. 10
Fig. 5. Acid rain effect on statues
Source: Google images

11. How it Affect Aquatic Organisms
Acid rain causes a cascade of effects that harm or kill aquatic
organisms, reduce population numbers, completely
eliminate organisms species from a water body, and
decrease biodiversity. Not all aquatic organisms can tolerate
the same amount of acid in water, for example, frogs can
tolerate water that is more acidic (i.e., has a lower pH) than
trout. Others, however, are acid-sensitive and will be lost as
the pH declines. Generally, the young of most species are
more sensitive to environmental conditions than adults. At
pH 5, most fish eggs cannot hatch while at lower pH
levels, some adult fish die. Lakes that have are very acidic
and have no aquatic organisms are called “dead lakes”.
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12. 12
Fig. 6. Fish killed by acid rain
Source: Google images

13. 13
Fig. 7. Summary of the effects of water acidification on physiology and behaviour of fish.
Source: Ikuta et al. 1997

14. How Does Acid Rain Affect Ecosystems
The plants and animals living within an ecosystem are highly
interdependent. For example, frogs may tolerate relatively high
levels of acidity, but if they eat insects like the mayfly, they may
be affected because part of their food supply may disappear.
Because of the connections between the many fish, plants, and
other organisms living in an aquatic ecosystem, changes in pH or
aluminum levels affect biodiversity as well. Thus, as lakes and
streams become more acidic, the numbers and types of fish and
other aquatic plants and animals that live in these waters
decrease. And because there are so many changes, it takes
many years for ecosystems to recover from acid
deposition, even after emissions are reduced and the rain
becomes normal again (Ikuta et al., 1999) 14

15. 15
Fig. 8. Chart showing the different levels of pH toleration of aquatic organisms
Source: Google images

16. REDUCING THE HARMFUL EFFECTS
Awareness is being generated among the masses worldwide
about acid rain and its harmful effects. The following are a
few steps that could be taken in this regard to reduce, or even
eliminate, the acid deposition problem.
 Use of alternative energy sources
The use of other sources of electricity besides fossil fuels such
as nuclear power, hydropower, wind energy, geothermal
energy, and solar energy can help to reduce the emissions of
sulphur dioxide and nitrogen oxides.
Also the use of alternative energies available to power
automobiles, including natural gas powered vehicles, battery-
powered cars, fuel cells, and combinations of alternative and
gasoline powered vehicles. 16

17. REDUCING THE HARMFUL EFFECTS (cont.)
 Clean up smokestacks and exhaust pipes
Another option for reducing SO2 emissions, involves using coal
containing less sulfur, washing the coal, and using devices called
scrubbers to chemically remove the SO2 from the gases leaving the
smokestack. Power plants can also switch fuels using technologies that
don't burn fossil fuels; for example burning natural gas creates much
less SO2 than burning coal.
 Liming
Limestone or lime (a naturally-occurring basic compound) can be added
to acidic lakes to "cancel out" the acidity. It tends to be expensive and is
considered a short-term remedy because it has to be done repeatedly to
keep the water from returning to its acidic condition.
 Other options is the actions taken by individuals; since energy
production causes the largest portion of the acid deposition problem,
individuals are advised to conserve energy. 17

18. Prevention of Acid rain is very important for the future of our
environment. Since acid rain is caused mainly by the emission of
sulphur dioxide from coal-fired power plants. There are a number of
preventions, including: switching fuel sources to natural gas, oil, or
renewable energy sources; switching to low-sulphur coal; removing
the sulphur from the coal before burning; using fluidised-bed
combustion processes to burn the coal; and removing the sulphur
from the smoke stack after combustion through the installation of
pollution control equipment. Other prevention methods are catalytic
converters, road traffic restrictions, and equalising acidity in affected
water systems by using powdered limestone and reduction in the
sulphur content of fuels. Things you could do in the community to
prevent are protest against the use of coal fire in industry, walking
more and driving less, buy fuel efficient cars or alternative fuel
powered vehicles and head community campaigns promoting
awareness of the issue.
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PREVENTION

19. CONCLUSION
Acid rain, which is a broad term used to describe several ways
in which acids fall out of the atmosphere is an environmental
problem that affects not only aquatic organisms but also
humans and the ecosystem in general. However like many
other environmental problems, acid deposition is caused by
the cumulative actions of millions of individual people.
Therefore, each individual can also reduce their contribution
to the problem and become part of the solution. Individuals
can reduce the problem directly by conserving energy, since
energy production causes the largest portion of the acid
deposition problem.
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20. THANK YOU
FOR YOUR TIME
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