Acid Rain
My first question is , "What is Acid Rain?" You hear about it all the
time
in the news and it is very important to the earth’s ecosystem. In
simple
terms, acid rain is rain that is more acidic than normal. All objects
in nature
have a certain level of acicicity but acid rain has too much acid
in it. Acid
rain is a complicated problem, caused by air pollution. Acid
rain's spread and
damage involves weather, chemistry, soil, and the life
cycles of plants and
animals on the land and from acid rain in the water.
Acidity is measured using a
pH scale, with the number 7 being neutral.
Therefore, a body with a pH value of
less than 7 is acidic. On the other
hand, a value greater than 7 is basic. The
pH of 5.6 has been used as the
baseline in identifying acid rain, although this
value is controversial,
therefore, acid ran is any rainfall that has an acidity
level above what is
expected in non-polluted rainfall. Any precipitation that
has a pH value of
less than 5.6 is considered to be acid precipitation. Readings
of pH 2.4--as
acidic as vinegar--were recorded during storms in New England.
During one
particularly acid summer storm, rain falling on a lime-green
automobile
leached away the yellow in the green paint, leaving blue raindrop
shaped
spots on the car. Scientists have found that pollution in the air from
the
burning of fossil fuels is the main cause of acid rain. The major
chemicals
in air that help to create acid rain are sulfur dioxide, known as
(SO2), and
nitrogen oxides, known as (NOx). Acid rain is formed high in the
clouds where
sulfur dioxide and nitrogen oxides react with water, oxygen, and
oxidants. This
lethal mixture creates a mild solution of sulfuric acid and
nitric acid.
Sunlight often increases the speed at which the reaction
occur. Rainwater, snow,
fog, and other forms of precipitation containing
these new solutions of sulfuric
and nitric acids fall to earth as acid rain.
Acid rain does not make up all of
the acidity that falls back to earth from
pollutants. Only half of the acidity
in the air falls back to earth through
dry deposition as gases and dry
particles. The wind blows and then these
acidic grains are blown onto buildings,
cars, homes, and trees. In some
cases, these particles can eat away the objects
which they land on. Dry
deposited gases are sometimes washed from trees and
other surfaces by
rainstorms. When this occurs, the runoff water adds the new
acids to the acid
rain, making a more acidic combination than the falling rain
by itself. One
of the main causes of acid rain is the sulfur dioxide. Sulfur
dioxide is one
of the main ingredients which make up the deadly combination that
forms acid
rain. Some of the natural sources that emit this gas are rotting
vegetation,
volcanoes, plankton, rotting animals and sea spray. However, the
burning of
fossil fuels, such as coal and oil, do not help the situation and are
largely
to blame for approximately half of the emissions of this gas in the
world.
Water moves through living plants, animal, streams, lakes, and oceans in
the
hydrologic cycle. In that cycle, water evaporates from the land and sea
into
the atmosphere. Water in the atmosphere then condenses to form clouds.
Clouds
release the water back to the earth as rain, snow, or fog. When water
droplets
form and fall to the earth, they pick up particles and chemicals
that float in
the air. Even clean, unpolluted air has some particles such as
dust or pollen.
Clean air also contains naturally occurring gases such as
carbon dioxide. The
interaction between the water droplets and the carbon
dioxide in the atmosphere
gives rain a pH of 5.6, making even clean rain
slightly acidic. Other natural
sources of acids and bases in the atmosphere
may lower or raise the pH of
unpolluted rain. However, when rain contains
pollutants, especially sulfur
dioxide and nitrogen oxides, the rain water can
become very acidic. This problem
is a problem of natures balance being
tampered with. If not polluted, normal
precipitation would react with
chemicals that are derived from bedrock in the
air, soil, lakes, and streams
and this rain would be neutralized. Since the
precipitation is highly acidic,
these natural buffering chemicals will be
destroyed. When this occurs, the
natural buffering effect does not occur, and
nature won’t keep it’s balance
Acid rain has been a big problem for a long
time. Research on acid rain is
just starting to make progress. In the past,
little was known about the
causes and effects of acid rain. Lakes, rivers,
oceans, and other aquatic
ecosystems are largely affected by acid rain. The
reason why acid rain has
such a large affect on aquatic ecosystems is because
there as so many routes
in which acidic chemicals can enter the water. Chemical
substances enter the
water in different ways. Some of the ways acidic chemicals
enter waterways
are as dry particles. These chemicals can also get into the
water in forms
such as rain, hail, dew, fog and snow. Another way that acids
enter the lakes
is called spring acid shock. An example of spring acid shock is
when snow
melts in the spring rapidly as a result of a sudden temperature
change. The
acids in the snow are then put into the soil. The melted snow in
return runs
off to smaller water sources, and gradually make their way into the
larger
water ecosystems. This causes a sudden drastic change in the pH
level.
The aquatic ecosystem doesn’t have time to adjust to the drastic
change. This
is also very dangerous because in the springtime many aquatic
species are
reproducing. Some of these species lay their eggs in the water to
hatch. The
sudden pH change can cause serious deformities in their young or
even kill off
the whole species since the young spend a lot of their crucial
primary life
cycle in the water. Sulfuric acid in water can affect the fish
in the water in
two ways: directly and indirectly. Sulfuric acid directly
interferes with the
fish's ability to take in salt, oxygen and nutrients
crucial for daily life.
Osmoregulation is the process of maintaining the
delicate balance of salts and
minerals in their tissues. For freshwater fish,
maintaining osmoregulation is
key in their survival. Acid molecules, which
are a result of acid rain in the
water, cause mucus to form in the fish’s
gills. This in return prevents the
fish from absorbing oxygen. If the fish
are unable to absorb oxygen, the
consequence could be the eventual
suffocation of fish and the low pH could throw
off the balance of salts in
the fish tissue. Salt levels such, as the calcium
(Ca+2), levels of some fish
cannot be maintained due to pH change. This can
results in poor reproduction.
The fish’s eggs produced would be damaged, they
could either be too brittle
or too weak. The decreased Ca+2 levels also result
in weak spines and
deformities. Acid Rain is very tragic when it come to the
life of fish, but
when nitrogen-containing fertilizers are washed off into the
lakes, the
nitrogen stimulates the growth of algae, which logically would mean
an
increase in oxygen production, thus benefiting the fish. This can
be
beneficial, but because of increased deaths in the fish population due to
acid
rain, the decomposition process uses up a lot of the oxygen, which
leaves less
for the surviving fish to take in. Indirectly, sulfuric acid
releases heavy
metals present in soils to be dissociated and released. For
example, aluminum
(Al+2) is harmless as part of a compound, but because acid
rain causes Al+2 to
be released into the soils and gradually into the lakes,
it becomes lethal to
the health of the fish in the lakes on its life forms.
Some of the pH level
effects are ; At pH level six basic forms of food die
off for fish. The food
sources cannot survive at this pH level. At a pH level
of 5.5 there are more
deformed adult fish due to lack of nutrients. The fish
cannot reproduce. The
young have difficulty staying alive, and eventually the
older fish will die of
suffocation. At pH level 5.0 the whole fish population
will die off. At pH level
4.0 all life forms will die. Fish, being one of
the most important members of
the food chain, provide nourishment for other
creators. Since acid rain is
affecting fish, this makes it dangerous for
other creators including humans to
eat the fish. Other sea dwellers such as
amphibians are also affected by acid
ran. The amphibian embryos have
membranes that are too tough because of the
acids, such that they are unable
to break through at the proper time. So, they
continue to grow, only to have
deformed spines. The affects on water forms are
the greatest and most tragic
of all of the things that acid rain affects. Acid
rain affects all that eat
seafood or any other water dwelling life form. Another
things impacted by
acid rain are forests and soil. When acid rain falls onto the
earth's surface
it causes a lot of damage. The soil is robbed of some vital
things. Aluminum
that is always present in the soil is freed, and the toxic
element is
absorbed by the roots of trees. The trees in turn are starved and
deprived of
vital nutrients such as calcium and magnesium. Sulfuric acid returns
to
earth. When the sulfuric acid returns, it clogs up the stomata in the
leaves,
stopping photosynthesis. In addition, severe frosts may also further
aggravate
this situation. With sulfur dioxide, ammonia and ozone present in
the air, the
frost-hardiness of trees are reduced. Ammonia mixes with sulfur
dioxide and
forms ammonium sulfate. This product forms on the surface of the
trees. When
ammonium sulfate reaches the soils, it reacts to form both
sulfuric and nitric
acid. Such conditions also stimulate the growth of fungi
and pests like the
ambrosia beetle. When trees are under such stress, they
release chemicals such
as terpenes which attract the ambrosia beetle. Acid
rain also affects the
atmosphere. The affects on the atmosphere are mostly
due to dry deposition that
was mentioned earlier. The floating particles can
contribute to haze, which
affects visibility. This makes navigation
especially hard for air pilots. The
acid haze also inhibits the flow of
sunlight from the sun to the earth and back.
Acid rain also affects
architecture. Architecture is affected by both dry
precipitation and wet
precipitation. When these particles land on building they
eat into the
concrete eventually destroying them. This is a potential danger
because the
infrastructure of the buildings can be destroyed, thus hurting
people
occupying the building Acid Rain also has a direct affect on you and
I.
The SO2 and NO2 emissions give rise to respiratory problems such as
asthma, dry
coughs, headaches, eye, nose and throat irritations. The indirect
affect of acid
rain are on the food that we eat. Acid rain is absorbed in
fruits, and in the
tissues of animals. Although these toxic metals do not
directly affect the
animals, they have serious affects on humans when they
are being consumed. Acid
rain is a huge problem which affects every person
living in the world in some
sort of way. Acid rain is a problem that can be
reduced but not stopped
completely due to the needs of our modern society.
Some ways that we could help
to reduce acid rain is by recycling, carpooling,
and reducing. Acid rain is a
problem that can be controlled but it is up to
the people of earth to control
the problem.
Bibliography
1.
Heij, G.J. and J.W. Erisman (Editors). Acid Rain Research: Do we have
enough
answers? New York: Elsevier, 1995. 2.Comptons New Media Encyclopedia
1996
3. White, James C. (Editor). Acid Rain: The Relationship between
Sources and
Receptors. New York: Elsevier, 1988. 4.FAQ on Acid
Rain(http://ns.doe.ca/aeb/ssd/acid/acidFAQ.html)