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					                        !!-- Global Warming: --!!

       !!-- A Deadly Threat for Human Life --!!


    Global warming is one of the major environmental issues facing the world today. Global
warming refers to an average increase in the Earth's temperature, which in turn causes changes in
climate. An increase in the temperature of the Earth’s surface may lead to changes in rainfall
patterns, a rise in sea level, and a wide range of impacts on plants, wildlife, and humans. One
cause for Global Warming is called the Greenhouse Effect. The Greenhouse Effect results from a
four step process. First, sunlight radiates from the sun, through space, to Earth's atmosphere.
Second, the sunlight enters the atmosphere and hits Earth. Some of it turns into heat energy in
the form of infrared light. The heat is absorbed by surrounding air and land, which in turn makes
it warm. Third, infrared rays, which are remitted into the atmosphere, are trapped by greenhouse
gases. Finally, the gas then absorbs the light and is remitted back to the Earth's surface and
warms it even more. Human activities have altered the chemical composition of the atmosphere
through the buildup of greenhouse gases – primarily carbon dioxide, methane, and nitrous oxide.
While on average the globe will get warmer and receive more precipitation; individual regions
will experience different climatic changes, with different consequences for the local
environment. Those changes which are the subject of greatest concern are: a rise in sea level,
climatic changes and more extreme weather events, and a greater potential for heat-related
illnesses and deaths.

        First, an increase in the Earth’s surface temperature is causing mountain glaciers the
world over to recede resulting in a rise in sea levels. According to the Union of Concerned
Scientist of USA (ucsusa) the Arctic ice pack has lost about 40 percent of its thickness over the
past four decades. Global sea level is rising about three times faster over the past 100 years
compared with the previous 3,000 years (ucsusa). Melting of glaciers could raise sea levels and
devastate flat and low-lying coastal regions. Fresh water from glaciers could also disrupt the
churning flow of sea water that normally blunts extreme temperature changes. “The ocean’s ice
cover has thinned by an average of four feet- some 40 percent- since the 1960s, and satellite data
show that the ice’s reach has receded 5 percent. More recently, relatively warm Atlantic water
has pushed 20 percent farther into the Arctic than scientists have ever seen - and that water is 1.6
degree f warmer than it was only a decade or so ago” ( Hodges 19). If the arctic continues to
warm, the consequences could be grave. Some scientists think there’s a chance- remote but
conceivable- that the ocean’s summer ice cover could completely melt at some point in coming
decades. Dave Clark, a marine geologist at the University of Wisconsin says:
The absence of ice in the Arctic would completely change climate pattern for the northern
Hemisphere. In computer modeling if you take off the ice, even the circulation of the ocean
reverses. (Hodges 20)

        Global warming and sea level rising is no longer a debatable argument. In fact the
impacts of global warming are real. For example, Rising sea levels are endangering the tiny
Pacific Island nation of Tuvalu. The leaders of Tuvalu—a tiny island country in the Pacific
Ocean midway between Hawaii and Australia—have conceded defeat in their battle with the
rising sea, announcing that they will abandon their homeland. After being rebuffed by Australia,
the Tuvaluan asked New Zealand to accept its 11,000 citizens (Brown). In addition to island
nations, low-lying coastal countries are also threatened by rising sea level. In 2000 the World
Bank published a map showing that a 1-meter rise in sea level would inundate half of
Bangladesh's riceland. With a rise in sea level of up to 1 meter forecast for this century,
Bangladeshis would be forced to migrate not by the thousands but by the millions( Brown).
Secondly, global warming can cause climate changes and extreme weather events. According to
Union of Concerned Scientist of USA (ucsusa) since the beginning of the 20th century, Earth's
mean surface temperature has increased by about 1.1°F (0.6°C). Warming in the 20th century is
greater than at any time during the past 400 to 600 years (ucsusa). Globally average precipitation
is projected to increase, but both increase and decrease will occur depending on the specific
global region. “Precipitation is projected to increase in both summer and winter over high
latitude regions; in winter over northern mid-latitudes, tropical Africa and Antarctica; and in
summer over south and East Asia. Conversely, precipitation is projected to decrease in winter
over Australia, Central America and southern Africa” (Watson 27). Major climate-driven
changes across five continents, changes that are leaving millions homeless, destitute and in
danger. Global warming can cause more heat waves and droughts, resulting in more and more
conflicts over water resources. Global warming is a major threat for fresh water supplies. In
many parts of the world, the signs of global warming are very dramatic. Journalist and
environmental activist Mark Lynas expressed his experience about impacting of global warming
in Alaska,

        The manager of the hostel where I stayed, a keen hunter, told me how ducks had been
swimming on the river in December (it’s supposed to freeze over in autumn); how bears had
become so confused they didn’t know whether to hibernate or stay awake, and that winter
temperatures, which used to plummet to 40 degrees below zero, now barely touched 25 below.
(Lynas 60)
Finally, rising temperatures and increased precipitation are likely to have detrimental effects on
human health. The result of climate changes could be a greater potential for heat-related illnesses
and deaths, as well as an opportunity for infectious diseases, such as, malaria, encephalitis, and
Ebola to spread into new geographical areas that were previously free from them. Assessing
what global warming will mean for human health, however, is a very hugely complex task,
clouded by uncertainties. The US National academy of sciences conducted a study on global
warming and infectious diseases that was published in April 2001. Among the climate triggered
health threats that the studies spotlight are these: “vector-born infectious diseases-such as
malaria, dengue, schistosomiasis, leishmaniasis and encephalitis- may alter their geographical
ranges and seasonality, spreading into new regions and declining in others. Heat-related deaths
could rise in response to more frequent and more intense heat-waves, particularly in temperate-
zone cities and among the elderly. Cold-related mortality might decline but this reduction might
be offset by the increase in heat-stress mortality. Air pollution in urban areas would likely
increase as air temperatures warm- particularly the concentration of ground-level ozone, which is
damaging to respiratory health. Malnutrition risks, and the diseases that accompany malnutrition,
would rise as agricultural practices adapt to new patterns of temperature, rainfall and soil-
moisture conditions. Warming oceans could promote more frequent toxic algal blooms, increase
the incidence of diarrhea related diseases, and spread the risk of poisonings from fish and
shellfish toxin” (Agnew 71). Population displacement, forced by rising sea levels or extreme
weather or agricultural collapse, would complicate the public health challenge. Large numbers of
refugees moving into already populated areas, crowded together, hungry and perhaps starving,
without shelter or adequate sanitation, is a formula for spreading infectious diseases.
Environmental health expert of WHO (World Health Organization) Dr. Carlos Corvalan says,
We don’t yet know how severe the impacts are going to be or how accurate the predictions of
environmental change are, but the evidence is accumulating, and ecological and human impacts
of global warming will strike hardest at developing nations, particularly the poorest. (Agnew 70)




Conclusion:
        There is much debate about the causes and effects of global warming, but with the benefit
of scientific data, the trends toward a change in the makeup of the atmosphere are clear. Global
Warming is a problem that we must deal with immediately. The changes in precipitation and
temperature patterns, ocean circulations, polar cap coverage, and mountain ice will impact all
peoples of the world. It is important that governments, industries and communities understand
the changes that are occurring and take immediate steps to alter the rate of change where possible
and to prepare for the impacts on populations that will occur with global warming.

*****************************************************************************
            !!-- Man’s EffEct On EnvirOnMEnt --!!



         Man has had many far-reaching effects on the environment over the years. Global warming,
pollution and the damage to the ozone layer are a few of the major things that can be heard about in the
news. Man has damaged the earth gradually over the years and this damage cannot be reversed, we are
now trying to stop any more damage being caused to the environment. For example, hedgerows have
been destroyed but now people have realised what effects this is having on the environment the
government are paying farmers to replant them instead of fencing. Not all of man's effects on the
environment are harmful some are beneficial. Conservation work is going on across the country and this
is helping to preserve the wildlife and countryside that we have left. The expanding human population has
placed a huge demand on the food production of the country. The resources are limited but the
population is increasing quite rapidly so the problems are growing. The demand for food means that
crops need to be perfect so the use of fertilisers and herbicides is increasing too.


         One of the problems in the countryside affecting the environment is the disposal of effluent and
other pollutants. The main type of waste that we have to dispose of is organic effluent particularly from
farms and sewage works. This is disposed of in several ways, the main one being pumping it into the sea
and rivers around the country. In more recent years sewage recycling plants have been developed to
reuse the water in the waste. Water treatment works are used to treat the waste before it is pumped into
the river or sea.

          The disposal of the waste is accomplished in several ways. Direct removal into a stream or lake is
the most commonly used means of disposal. In parts of the world that are faced with worsening shortages
of water for both domestic and industrial use, authorities are reusing appropriately treated wastewater for,
irrigation of non-edible crops, industrial processing, recreation, and other uses. In one such project, the
Potable Reuse Demonstration Plant in Denver, Colorado, the treatment process uses normal primary and
secondary treatment followed by lime clarification to remove suspended organic compounds. During this
process, an alkaline state is created to improve the process. In the next step, re-carbonation is used to
bring the pH level to neutral. Then the water is filtered through several layers of sand and charcoal, and
ammonia is removed by ionisation. Pesticides and any other dissolved organic materials still present are
absorbed by a granular, activated-carbon filter. Viruses and bacteria are then killed by ozonisation. At this
stage the water should be cleansed of all contaminants, but, for added reliability, second-stage carbon
absorption and reverse osmosis are used, and chlorine dioxide is added to obtain the highest possible
water standard.

         The other main place that effluent is disposed of from is industry. Industrial plants put their waste
into the main drains, because they pump it into the main drains it has to be a particular pH i.e. neutral
(between pH6 and pH10). If the pH fluctuates out of this range, there are valves along the main pipe line
from the industrial works that close to prevent the effluent leaking into the main sewage system. The pH
can then be regulated by either adding caustic soda (an alkaline) or hydrochloric acid to neutralise it
again. If the valves did not close and the effluent were allowed to travel into the sewage works then it
would kill all the nitrifying and denitrifying bacteria that break down the waste. The bacteria are very
sensitive to the chemicals that are used and if these levels fluctuate too much, it will kill the bacteria and
the whole decomposition process will be affected. The bacteria remove the ammonia in the effluent.
There are filters in the water treatment works that sieve out a lot of the suspended solids and there are
chemicals which are added to make the rest of the solids bind together with the help of bacteria so that
they come to the surface and can then be filtered off. The water that eventually comes out is pumped
from an outlet into the river unless it is to be recycled then it goes on for further cleansing. The effluent
that is pumped into the streams gives the decomposers in the water a huge food supply, therefore they
use up much of the oxygen and eutrophication - death of the waterway - results. The decomposers
deprive the other organisms such as fish and crustaceans of oxygen causing them to die. This in turn
affects the whole food chain.

        Phosphates are products formed by the replacement of some or all of the hydrogen of a
phosphoric acid by metals. Depending on the number of hydrogen atoms that are replaced, the resulting
compound is described as a primary, secondary, or tertiary phosphate. Also known as trisodium
phosphate, tertiary sodium phosphate is used as a detergent and water softener. Primary and secondary
phosphates contain hydrogen and are acid salts. Phosphates are important to metabolism in both plants
and animals. Primary calcium phosphate, Ca(H2PO4)2, is an ingredient of plant fertilisers. When it is
used as a fertiliser it can be washed into the waterways by the rain and pollute the rivers and streams.
Increasing attention has been focused on the environmentally harmful effects of phosphates in household
detergents. Detergents containing phosphates are known to be water pollutants because phosphates are
a primary nutrient of algae. When algae grows in excess, it can choke a lake or river and draw off needed
oxygen from aquatic life. This is called eutrophication

         Nitrates are also harmful to the environment. Calcium, sodium, potassium, and ammonium
nitrates are used in fertilisers to provide a source of nitrogen for plant growth. If these nitrates get into the
water flow then they can, like phosphates, have damaging effects on the life that live there.

          Factory chimneys emit Sulphur Dioxide, which has to be monitored. Inside the chimneys are
several filters that sift out the solids in the emissions. Sulphur dioxide emitted into the atmosphere by
industrial processes is ultimately converted into dilute sulphuric acid, returning to Earth as acid rain. For
this reason, sulphur dioxide is a major cause of air pollution. Acid rain is rain with a greatly lowered pH.
Oxides of nitrogen are also emitted from car exhausts that also add to the formation of acid rain. The acid
rain in turn comes down and erodes buildings and other things. In heavily industrialised areas of America,
ladies have reported holes appearing in their tights when rain falls on them. In areas with plenty of
limestone rocks, the effects are reduced because the acid reacts with the rocks and neutralises the rain.
In areas without limestone, lakes become acidic, leading to the death of the wildlife. Trees are also killed
as a direct result of acid rain. Many governments are ignoring the warnings and not controlling the
emissions from their industry before it is too late.

         Crude oil, known as petrol, is used in the manufacture of fertilisers, medicines, plastic, building
materials, paints and to generate electricity. It is also used for the fuelling of transport such as cars and
planes. Petrol contains hydrocarbons and sulphur. When the hydrocarbons and sulphur are burned for
use they give off sulphur dioxide and carbon dioxide. These gases are harmful to the environment.
Sulphur dioxide forms sulphuric acid and causes acid rain, carbon dioxide adds to the greenhouse effect.
The greenhouse effect means that the levels of carbon dioxide and other greenhouse gases that usually
prevent heat loss from the earth are increasing. This results in raised temperatures on earth leading to
partial melting of the polar ice caps. If the ice caps melted too much some countries would be flooded, if
they were all to melt then the whole world would be underwater.

        There is a need to produce more food for the population and a need to preserve the wildlife and
the environment. It is essential to satisfy the needs of the expanding population but it is also essential to
preserve the environment. Living organisms are dependent on each other, if a tiny little fungus or algae
plants were destroyed then the rest of the food chain would be affected. The algae or fungi are the
producers so the primary consumers have nothing to eat so they die and the secondary consumers then
have nothing to eat so they die. Plants and can be used for many purposes which is why they are
becoming extinct. Drugs have been derived from plants. Genetic variation also decreases with the loss of
species and new genes can never be discovered e.g. for crop breeding. The reduction of trees is leading
to more carbon dioxide in the air and therefore increasing global warming.

         The government is trying to reverse some of the effects man has had on the environment by, for
example, paying farmers to replace hedgerows in their fields which had previously been removed to make
room for more crops. Factories have to monitor the amount of emissions that come from their chimneys
very closely and if they emit too much sulphur dioxide or other harmful chemicals then the factory can be
closed down. Factories also have to monitor the amount of chemicals that they pump into the drains, they
have to neutralise the effluent before it is pumped into the main drainage system to prevent any
chemicals getting into the main sewers and into the rivers and affecting the ecosystem of the rivers.
Some waste can be recycled, at the water treatment works they can make the water clean enough, may
be not to drink, but to water non-edible crops and for industrial processes and recreation.

        Crop rotation is another way in which the land is being preserved a little more. Different crops are
being grown in different places so that the same nutrients aren't being used from the same piece of soil
every time and therefore the nutrients are being used in equal quantities. The nutrients in the soil then
have time to replenish themselves over the years. In addition, natural fertilisers are being used like
farmyard manure instead of phosphates and nitrates. This means that the nutrients are released slowly
as they decay and therefore improve the structure of the soil.

          The human population is expanding rapidly and the demand for food is increasing too. There are
limited resources with which to produce this food so therefore the demand is greater then the production.
Farmers are under pressure to produce more and more food. The crops they produce all have to be
perfect, there can be no waste so herbicides and fertilisers have to be used to maintain the high
production rate. The farmland has to be maintained, this is done with regular grazing of cattle to keep
eating the grass and with ploughing to prepare the soil for re-use next time. Ploughing removes the plants
that would compete with the crop and gives the seedlings the chance to establish themselves quickly and
easily. Ploughing also helps to aerate the soil. Harrows are used to break up the lumps of soil and make
the surface smooth. This allows the seedling to be planted at a consistent depth. The farmer uses
herbicides to control the weeds among the crops, to do this he uses a crop sprayer. To harvest the crops
a combine harvester would be used. This cuts down the crop and chops it and then it is pout into a tractor
and trailer. Other crops such as potatoes and peas are harvested differently, peas with a pea viner which
picks the peas from the rest of the plant. Potatoes are picked using a potato drill. The farmer will then use
fertiliser or farmyard manure to replace the nutrients removed by the plants, they would use a muck
spreader to do this. Cattle remove nutrients from the soil so it has to be fertilised regularly to maintain the
productivity and allow the animals to eat.

         The demand on agriculture to increase food production conflicts greatly with the need to protect
the environment. Organic crops are becoming more popular as they don't have any fertilisers on them,
which affect the environment. Many farmers are turning to organic crops and the government is
introducing incentives to try to encourage farmers to grow organic food as it can be expensive. Interest
free loans are being introduced for farmers who will convert their dairy farms to organic ones. Oilseed
rape crushers have been introduced to produce organic oilseed rape. The oil is destined for human
consumption and the by-products are for animal feed. This is to try to encourage organic oilseed rape to
be grown in the UK as it is not currently and has to be bought outside the UK. Farmers are being offered
money by the EU to meet agri-environmental measures. The scheme has been set up for the next seven
years and is designed to improve the environment. Farmers are being paid to convert farmland into
woodland. There are increasing fuel prices to try to discourage people from using their cars as much and
protect the environment. But these prices are hitting farmers badly, as they can't afford to run their
machinery to maintain and harvest their crops. These crops are ultimately our food therefore, the
increasing fuel prices to protect the environment are preventing as much food being produced.

         Organic food production seems to be a very good idea. It protects the environment as it doesn't
involve the use of herbicides and fertilisers and it allows the farmers to carry on producing food in large
enough quantities. The government incentives are helping farmers to become established in the organic
farming trades. With organic food becoming more popular with the consumer, the demand for organic
produce is increasing. Organic food tends to be more expensive as the entire crop isn't perfect but it is
environmentally friendly.

Conclusion:

         Man's effects on the environment are many but the effects are being slowed down and where
possible reversed. The consequences of many years of abuse to the earth are being realised and people
are trying to do something about it. Tillage operations that prepare the soil for planting and control weeds
expose bare soil to possible erosion by wind and water. An example is the Dust Bowl area of the United
States. The planting of crops and raising of cattle here left the soil exposed, which led to extensive wind
erosion during the 1930s. Erosion removes fertile soil and contributes to problems of air and water
pollution. Several techniques are used to combat erosion. Crop rotation is also being increasingly used to
hold soil in place between plantings. Still, many small-seeded crops require a finely worked seedbed, and
soil erosion cannot be eliminated. The dust bowl cannot be used for crops or cattle now. If crop rotation
and other land maintenance did not take place, this would happen to the land in the UK. Global warming
is being reduced as much as possible by the reduction of toxic emissions and wastewater is being
recycled instead of pumped into rivers and seas. Man is trying to reverse and slow down the effects on
the environment although some things cannot be reversed.

        **************************************************************************************************************
                         n!!—Ozone Depletion --!!



   Atmospheric ozone layer depletion is a serious problem currently facing the world. The ozone
layer protects humans, animals, and plants from harmful ultraviolet rays. Money and time are
being spent on ozone repair, but the problem still exists.

The ozone layer is a region of the stratosphere containing ozone, or O3 gas. The ozone layer is
essential to both plant and animal life on earth because it protects the surface from dangerous
ultraviolet light.

        However, industrial and domestic chemicals that are currently in use have been found to
destroy ozone, and the problem has escalated to an ozone layer "hole" above Antarctica. Ozone
levels there are 40 percent below normal, and there may be another ozone hole forming above
the Arctic region.1

       Ozone gas contains an extraneous oxygen atom in each molecule and is highly unstable.
This property lets ozone block out ultraviolet rays and makes it an essential part of the eco-
system. When harmful ultraviolet-B rays (wavelength 240-320 NM) come through the
atmosphere, the O3 molecules absorb the energy and one oxygen atom detaches from the
molecule. The stray atom will eventually collide with another O2 molecule and ozone will be
reformed. With this process, the level of ozone remains constant, as it has for millions of years.3

         Recently, a number of chemicals have been found to aid in the rapid destruction of ozone.
Most of these chemicals are compounds called chlorofluorocarbons, or CFC’s. It is difficult to
ban them outright because they have hundreds of industrial uses. CFC’s are widely used because
they are non-toxic, non-flammable, and inexpensive. Recent environmental legislation on both
the state and national levels has banned the use of some CFC’s, but the question of their disposal
still remains.4

        Chlorofluorocarbons do not destroy ozone directly. Compounds made from CFC’s photo-
decay series act as catalysts in the splitting of O3 molecules. When CFC’s reach the stratosphere,
they break down when struck by the intense light rays. The molecule splits and a majority of the
chlorine then forms hydrogen chloride or chlorine nitrate, which then decay into atomic chlorine
or chlorine monoxide.3
        These are the substances responsible for the physical destruction of ozone. As they come
in contact with an ozone molecule, they cause the third oxygen atom to detach and form an O2
molecule with another stray oxygen atom. Since they don’t react with the oxygen, the chlorine
compounds remain intact and can destroy up to 150,000 ozone molecules each.3

       There are a number of different CFC’s. The compounds most responsible for ozone layer
destruction are CFC-11 (trichlorofluoromethane), CFCl3; CFC-12 (dichlorodifluoromethane),
CF2Cl2; and CFC-113 (1,1,2 trichlorotrifluoroethane), CF2ClCFCl2. All of these compounds are
excellent refrigerants, and CFC-12 is marketed by DuPont as Freon™.3

        The word "CFC" has become a generic term referring to any substance that is deleterious
to the ozone layer. However, many destructive compounds are not CFC’s by definition. All
ozone-destroying compounds contain at least one of two common elements: chlorine, or the
more catalytic bromine. Compared atom-to-atom, bromine can destroy 10-100 times the number
of ozone molecules as chlorine. Fortunately, its atmospheric concentration is much smaller.3

       One of the other O3-destructive groups is called the hydrochlorofluorocarbons, or
HCFC’s. HCFC’s are organic compounds in which not all of the hydrogen atoms have been
replaced by chlorine or fluorine. One such compound is R-22 (HCFC-22), CHClF2.3

        Some other non-CFC compounds that destroy the ozone layer include carbon
tetrachloride (tetrachloromethane), CCl4; methyl chloroform (1,1,1 trichloroethane), CH3CCl3;
and methyl chloride (chloromethane), CH3Cl.3

     The result of ozone layer depletion is a increase in ultraviolet rays at the surface.
Humans, animals, marine life, and plants are all susceptible to UV radiation damage.

        Current studies indicate that ultraviolet rays could be disastrous to the marine eco-system.
High UV concentration causes phytoplankton, microscopic organisms at the base of the food
chain, to decrease their reproductive activity. Although there is no serious widespread effect
now, the problem may escalate in future years.3

       Numerous studies have proven that ultraviolet radiation, in both the UV-A and UV-B
forms, causes skin cancer. Of the three types of skin cancer, basal cell carcinoma, squamous cell
carcinoma, and melanoma, 90 percent of all cases can be attributed to overexposure to UV rays.
Other effects of increased ultraviolet exposure, including sterility and cataracts, are currently
under investigation.3

         Ultraviolet radiation has effects on plants as well, though different species react in
different manners. In a recent study of 200 plants, one variety of soybean plant showed a 25
percent reduction in growth when exposed to large amounts of UV rays. However, other types of
soybean in the same study were not affected. It is estimated that a reduction in ozone level as
little as 10 percent could seriously damage the world’s agricultural production.3
        The ozone layer is a complex problem since the atmosphere is constantly shifting and
diffusing. Many quick-fix theories exist, such as flying planes filled with ethane and propane
over the Antarctic region. When the planes release the gasses, they would react with the harmful
chlorine compounds and reduce their destructive power. However, the environmental effects
could be devastating and it would be a complex and costly project.2

       Another radical approach to CFC elimination is the use of lasers. Thomas Stix, a
Princeton University physics professor says that lasers tuned to the right frequency can break
CFC’s apart without affecting other atmospheric gasses. The disadvantage is the cost, which
would be roughly 10 billion dollars a year in electricity.2

       With ozone cleaning proposals being submitted and rejected on a daily cycle, many
environmentalists believe that the earth will repair itself if CFC production comes to a halt. A
number of CFC alternatives have been discovered, some of them are still under scrutiny for
suspected ozone-damaging qualities.

        The EPA has proposed the Significant New Alternatives Policy (SNAP) to evaluate
substances similar to CFC’s but not ozone-destructive. Over 250 compounds have been approved
for industrial and consumer use, and many of these compounds are already available.
Applications for these chemicals range from the manufacture of polystyrene to home fire
extinguishers.5

        One alternative being studied by major U.S. research laboratories are aerogels. Aerogels
are sol-gel substances that have the insulation properties of CFC-made foams. Aerogels can be
molded into any shape and are stronger than Styrofoam. While aerogels share many properties
with plastics, they cannot be shaped as easily. Therefore, until better manufacturing technology
can be implemented, aerogels will remain experimental.6



Conclusion:
        There is no obvious solution to the ozone layer problem. It has been estimated that if
CFC production ceased today, people living 70 years from now would still have to deal with
their effects. Also, conflicts between industrialists and environmentalists in government have
prevented sufficient CFC-blocking legislation from being fully effective. If the ozone layer can
be repaired, it will take a massive effort by the people and government to make it successful.

      ***************************************************************************
                                !!-- Pollution --!!



   Pollution is the introduction of harmful substances or products into the environment. It is a
major problem in America and as well as the world. Pollution not only damages the
environment, but damages us also. It has cause many problems ranging from lung cancer to the
greenhouse effect. It is all among us and but we continue to live in our own filth. What is the
reason behind this flawed logic? In this paper I will examine the problems and solutions for this
issue.

         Automobiles are undeniable the greatest source of pollution. The noise pollution created
by cars is immense. Another polluting effect of cars is the heat it creates. This heat makes it
unpleasant to be near the car while its running. And of course the most famous of the
automobiles evils is the exhaust. The toxic fumes given off as a byproduct of the combustion
engine are slowly deteriorating our lungs and our atmosphere. The exhaust is extremely toxic to
human beings. But why do we do continue to drive these walking time bombs. Some people will
say it is progress, but the majority drives it for the convenience. Why walk four miles in four
hours when you can drive the same miles in four minutes?

        Another popular source of waste is the post-consumer market. American citizens throw
away millions of tons of garbage each year, and this trash has to go somewhere. While there are
projects underway to clean and reuse this refuse most of it gets dumped into huge landfills.
These landfills are disgusting festering blisters on our country's landscape. But people continue
to consume and throw away more and more in the name of convenience. As they see it, when
things get old, throw it away and get a new one. They blame the government for the trash
problem, but the truth blame should be placed on themselves.

       The last great source of pollution lays in the businesses. Although not common,
businesses have been known to dump their waste products into streams, lakes, and rivers. This
may seem like a relatively small occurrence that really is not your concern, but you're wrong.
Each time one of these companies pollutes there are horrible consequences to pay. Mutations,
destroyed ecosystems, and human death have all occurred as a direct result of illegal dumping. It
contaminates our drinking water and soil. It causes entire communities of humans (not to
mention animals) to move on to new places not to return for at least a century. The pollutants
dumped by industry are so concentrated that a single barrel can destroy an entire lake's
ecosystem. Not only do companies dump chemicals, but also hot water. This hot water kills most
life it comes into contact with, but also causes an overgrowth of algae that covers the surface of
the lake, or pond, and blocks the light from reaching the bottom. This means the plant life cannot
grow, which mean the small bacteria and other microorganisms can't grow which means fish
can't feed which means the ecosystem dies.



Conclusion:
        Pollution like any other problem can be solved, but this is a long process. Individuals can
do their part to save the environment as well as themselves. Instead of driving, carpool, take the
bus or any other method of mass transit. This will cut down on pollution made by cars each year,
not to mention your gas bill. When it comes to the trash problem, take the time to sort your trash
and place it in the appropriate recycling bins. By recycling we reduce the amount of waste piled
onto the landfills. As for consumption, pay attention to how the products you buy are
manufactured and how they are packaged. Avoid those products made in 'unfriendly' ways
towards our mother earth. If a product encourages the destruction of land, or is of completely no
use don't buy it. And finally voice your opinion in the polls. If each individual did their part, we
will be creating a better world for ourselves as well as our children.

        ***********************************************************************
                                  !!-- HIV/AIDS --!!


        At the beginning of the 20th Century it was believed by many, including the United
States Patent Office, that there was nothing else to invent. Now, 100 years later at the beginning
of the new millenium the ancient Egyptian philosopher is more relevant, "there is nothing new
under the Sun". While HIV/AIDS may be a new disease, there is nothing new about a novel
epidemic, which can potentially or actually decimate a population. In the late middle ages, the
Black, now known as the Bubonic Plague, swept through Europe killing virtually half the
population. It was introduced by a single or small group of rats that came to Italy abroad a
trading ship from what is now Turkey. Small Pox transmitted by trade goods from the Hudson
Bay Company wiped out entire Native American tribes.

         There are other examples of diseases accidentally introduced to a population that had no
genetic immunity to them. Not to mention NASA's fear of an unbeatable super virus from outer
space. Now as in previous diseases, one of the dangers of HIV/AIDS is not only in its plague
proportions but also in the almost superstitious misunderstanding of the virus itself. In the
treatment of all illness, it is necessary to understand the emotional, economic, psychological and
sometimes even political impact that is brought about by the disease. This is particularly true
with a disease that is as devastating and heretofore misunderstood as HIV/AIDS. AIDS is the
punishment of God on sinners. AIDS is a plot by the CIA and the South African Government to
wipe out the population of black Africa. AIDS is the result of medical experimentation during
the development of the polio vaccine employing the use of rieces monkeys as guinea pigs. AIDS
is this, AIDS is that; AIDS is the end of the world.

         There is nothing new under the Sun. As we enter a new millenium, we are still controlled
by prejudice, fear and superstition. AIDS is not the end of the world, it is simply the latest
challenge the medical community needs to meet. There are new things to invent including an
immunization and cure for HIV/AIDS. But before that we must overcome the age-old
superstitious fears of the unknown and rise above the prejudices that we harbor of, "those
people". Let us understand HIV/AIDS. AIDS, the acronym for acquired immunodeficiency
syndrome, is the end stage disease of the human immunodeficiency virus (HIV). The result of
this disease is the destruction of the patient's immune system. Since the infected person has no
ability to fight off any infection because the virus is replicating in and destroying the cells that
normally fight infection, he/she then becomes susceptible to all opportunistic disease. Ultimately
death occurs as a result of the body's inability to fight infection. In the early 1980"sThe Center
for Disease Control and Prevention became aware that a new "virus" was effecting certain
segments of society. In 1985 researchers isolated a virus believe to be responsible for AIDS.

         Since that time the definition of this disease has changed many time. In 1993 the
definition was expanded to include conditions more applicable to women and injecting illegal
drug users. The new definition includes all HIV infected persons who have a CD4 cell count of
200 cells per microleter of blood. Also added were three clinical conditions. The current
definition states that AIDS is an illness characterized by laboratory evidence of HIV infection
coexisting with one or more indicator diseases. Most patients are diagnosed by these criteria.
HIV, as its name indicates is a virus and is therefore and obligate parasite. Such parasites can
only replicate while inside another living cell, or host. Parenthetically, HIV carries its genetic
material in RNA rather than DNA, and while in the host the virus converts RNA to DNA in
order to replicate. In seeking hosts, HIV is typically attracted to cells with CD4 + molecules on
their surface such as T-helper lymphocytes and similar cells. HIV reproduces at a phenomenal
rate, which causes massive destruction to the host cells. Cell destruction grows geometrically as
the virus replicates and seeks new host cells. Immune system breakdown primarily results from
the dysregulation and destruction of T-helper cells or CD4+lymphocytes. HIV is particularly
sinister in its attack on T-helper cells since one of the functions of those cells is to recognize and
alert the immune system to alien infections Initially the body's immune system, to a certain
degree combats the virus. However, since the virus virtually targets CD4+lymphatics or T-helper
cells, the immune system begins to loose its ability to even recognize let alone defend the
invading virus.The immune system remains relatively healthy as long as its count of CD4 cells is
greater than 500 per microliter of blood. Since CD4 + cells are designed to attack infection, they
are ironically drawn to the virus where they are subsequently infected. Ultimately the infection
spreads through the lymph system and lymphoid tissue becomes a reservoir for HIV replication.
As the disease progresses viral particles begin to enter the blood, this results in the infection of
body tissues where the virus begins to replicate in infected macrophages. Massive reproduction
of HIV in these cells causes the macrophage to burst allowing HIV to infect surrounding tissues.
The skin, lymph nodes, CNS, lungs and possibly even bone marrow are infected in this manner.
The virus at this point is well on its way to infecting every organ and tissue in the body.

         The symptoms of HIV, while highly identifiable to the patient, are general in nature and
are attributable to any number of causes. Early signs are consistent with flu like viruses. They
include abdominal pain, chills and fever, coughing, diarrhea, dyspnea, fatigue and headache.
Later symptoms are more severe and could be consistent with other diagnosis including cancer.
Some symptoms include disorders of the lymphatic system, malaise, muscle and joint pain, night
sweats, oral lesions, shortness of breath, skin rash, sore throat, weight loss and disorientation.
Additionally in the majority of HIV cases there are neurological manifestations as well. In
addition to symptoms preliminary diagnosis can be made by deduction in ascertaining whether or
not the patient engages in high-risk behaviors. If combinations of symptoms are present and are
accompanied by high-risk behaviors, then immediate clinical testing is advised. The individual's
blood is tested with ELISA or enzyme immunoassay (EIA), antibody tests that detect the
presence of HIV antibodies. If this test is positive than the same blood is tested a second time. If
a second EIA test is positive a Western blot is performed. This is a more specific confirming test.
Blood that tests positive to all three screenings is reported to be positive for HIV. IF the results
are inconclusive or indeterminate, the tests are repeated in 4 to 6 weeks. Again, if repeated and
the results remain indeterminate a culture is done to determine the viral load, this is done through
testing the DNA of the individual. These tests, whether positive or negative does not confirm nor
dismiss the diagnosis of AIDS. That is done according to the 1993 CDC definition of HIV. A
negative test is not an assurance that the individual is free of HIV since seroconversion takes up
to three months after initial infection. And if the individual continues to engage in risky
behaviors, transmission of the disease is likely to occur. At the present time it is believed that the
modes of transmission of the HIV virus are clearly identified and understood. Although generally
perceived by the public as a sexually transmitted disease, the method of HIV transmission is far
broader than simple sexual contact. As previously stated an obligate virus HIV requires a host
organism to survive. Once leaving the human body the virus is extremely fragile and cannot
survive outside of a host. Thus, HIV is transferred from person to person through infected body
fluids including blood, semen, cervicovaginal secretions, breast milk, pericardial, synovial,
cerebrospinal, peritoneal and amniotic fluids. It has been discovered that not all body fluids,
which contain HIV, transmit the virus. These fluids include saliva, urine, tears and feces. Further,
the ability for HIV to be transmitted via an infected fluid from one human to another is mitigated
by a variety of variables such as duration and frequency of exposure, the amount of the virus
inoculated and the virulence of the organism. The efficiency of the immune system is also a
factor. Once the virus has been passed to another individual, the newly infected individual then is
immediately capable of passing the virus to yet another individual. However, there are
apparently cycles when the probability of transmission is greater than others.

        The greatest potential for transmission occurs immediately after infected and during their
end stages of the disease. Nonetheless, it must be stressed that it is possible for HIV to be
transmitted at anytime during the entire disease spectrum. As a practical matter, the most
common method of transmission of HIV is through sexual contact. Vaginal and anal intercourse
are two of the three most common modes of HIV transmission. Throughout the world it is
believed that 75% of the total AIDS cases were the result of sexual contact. Anal intercourse is
the most frequent method of HIV transmission. This being the result of the frequent tearing of
the rectal mucosa which allows for direct infusion of the infected semen into the blood stream. In
all cases of intercourse the receptive partner is far more susceptible than the insertive partner.
This is not only true of anal and vaginal intercourse, but also for oral intercourse as well. HIV
can also be transmitted through oral genital sexual contact but such cases are considered rare.
The homosexual community was seriously impacted by HIV in the early days of the epidemic.
This was the result of the tendency for unprotected and casual sexual encounters as well as a
higher tendency for anal intercourse. The prostitution subculture was and still is seriously
impacted by the HIV virus. Causes of this include their numerous and varied sexual encounters,
pre-existing sexually transmitted diseases in addition to life style issues such as alcohol, smoking
and illegal drug use which weakens the immune system. Undoubtedly, the most powerful form
of transmission from one human to another of the HIV virus is through direct blood transfusions
employing infected blood. However, this has resulted in a miniscule number of cases. But the
accidental or intentional use of contaminated injecting equipment is the third most common
method of HIV transmission. The frequency of transmission being in the deliberate and repeated
use of contaminated syringes by infected persons generally occurs in users of illegal drugs.
These users typically share syringes and or other improvised injecting paraphernalia. While any
illegal drug can be injected, heroine and cocaine are the most widely used injectable illegal drug.
Less frequent forms of HIV transmission are vertical transmission and occupational exposure.
Vertical transmission occurs when a mother, either during pregnancy, at time of delivery, or after
birth (through breast-feeding) infects an infant. Occupational exposure is considered to be rare
but does occur. Studies ending in 1996 found 52 documented cases and another 111 cases of
possible occupational transmission. These cases, by enlarge, involved health care workers who
acquired the disease after percutaneous injury, mucocutaneous exposure and exposure through
open wounds. Most of these cases involve puncture wounds from needle stick type injuries. In
addition to health care workers, at risk personal include police officers, fire fighters, military
personal and prison employees. Since often the infectious contact is the result of elective human
behavior, there are strategies for preventing the continued spread of HIV virus. At the center of
these strategies is education which must be world wide, multileveled, intercultural and, of
course, non-judgmental. Modifying behavior through education would include teaching safe sex
practices, including stressing the proper and consistent use of effective condoms. Similarly for
the person who continues to use injected drugs, the use sterile needles must be taught.

        Deactivation of HIV requires only a 30-second exposure to 100% bleach. Instruction in
the cleaning methods used to deactivate HIV should be done. Education without resources can
only achieve marginal results. Therefor, although problematic and controversial it is necessary
after education to provide easy and in most cases free access to condoms, sterile needles, early
HIV testing and follow up medical treatment. As discussed, while most but not all HIV
transmission is the result of risky behavior, there are other causes of transmission as well.
Prevention then must entail education, discipline and procedures to minimize infection through
transfusion and safety procedures to prevent accidental transmission to people engaged in certain
occupations such as health care workers. On this last point herein lies another controversy which
is beyond the scope of this paper. That subject deals with what level should a person who is
living with the HIV infection have his/her medical and or other records reflect that fact. At what
point is the individual's right to privacy negated, if ever, in regards to the individuals who are
charged with caring for the infected person. The public at large uses interchangeably the terms
HIV and AIDS. This sloppy inaccuracy is one of the basis for the gross misunderstanding of the
disease. HIV is divided into two categories; type I, which is found throughout the world and has
resulted in most of the reported cases of infection, and type 2, which is localized to Western
African coastal nations and areas outside of Africa which have commercial and cultural relations
with that region. HIV infection ultimately leads to the disease of AIDS. But it is not AIDS in and
of itself. Within one to three weeks of initial exposure seroconversion occurs. This is the
detectable development of HIV antibodies. While the virus is usually detectable, acutely veril
and can be passed along, the infected person shows few or no symptoms. From the initial
exposure period or roughly from two to six months flu like symptoms will appear in the infected
person. The individual will begin to develop antibodies to fight the infection. The individual will
frequently appear to be acutely ill. Well before the end of the first year the HIV infection will
become asymptomatic. (It should be noted that during this period of time the disease is not
dorment but is systematically destroying t-helper cells). During this phase, which will last
perhaps into the eighth year of infection, the infected individual will manifest no symptoms of
disease. But, nonetheless, will be infectious. Between the eighth and tenth year of infection
symptoms of HIV disease will manifest. After ten to fourteen years HIV disease advances into its
terminal stage which is known as AIDS. This stage is epitomized by the body's inability to fight
any infection. Thus any infection is potentially fatal to the AIDS patient. In no way to make light
of the subject, it is reminiscent of the turn of the century novel by HG Wells, "War of the
Worlds". In this first science fiction story that deals with an alien invasion of earth by
undefeatable machines, human bacteria proves lethal to these unstoppable forces. Similarly, the
most mundane infection is a potential lethal agent to the AIDS patient. However, some
opportunistic infections are more frequently associated with AIDS patients than others.

        Of these opportunistic infections the most frequently encountered are those that are
respiratory in nature, particularly pneumoncystic carinii pneumonia and Kaposi's sarcoma.
Interestingly, prior to the discovery of HIV/AIDS these two diseases were extremely rare and the
dramatic increased occurrence of chronic ailments lead to the discovery of HIV/AIDS. While
respiratory system diseases or organisms are most typical other OI can, with fatal consequences
strike AIDS patients. The OI can attach any of the body's systems including the integumentary,
gastrointestinal and neurologic systems. For any of these diseases a variety of diagnostic tests are
appropriate and similarly with each disease a variety of treatment regimes have been established.
However, there is no cure for AIDS. This is not to say that in the early stage of the disease the OI
may be successfully resolved. But in the final analysis the OI that strikes the late stage AIDS
patient will at some point become fatal. There are several drugs that are available for the
treatment and management of opportunistic disease associated with AIDS. Prophylactically used
these medications have contributed to the decrease morbidity associated with HIV infection. The
individual must take these medications throughout their lives to attempt to control the
opportunistic disease as the body's immune system degenerates. These drugs are more effective
if used in combination with each other, combination therapy has become the standard of care.
These "cocktails" are more effective than single drug therapy. Since patients have become
resistant to many drugs over the long periods of time they must take them, studies have shown
that combinations of antiviral drugs may reverse the resistance that has taken place. However,
the side effects of these medications are severe, at best. Nucleoside Analogues: zidovudine is the
drug of choice to be used initially in combination therapy. Side effects of headache and nausea
usually resolve within one month. Other side effects can be more serious such as
granulocytopenia, thrombocytopenia, seizures, bone marrow suppression and anemia. Some of
these side effects only occur after long term use. This class of drugs inhibits replication of HIV
virus by incorporating into cellular DNA thereby terminating the cellular DNA chain.

        Didanosine, which is in the same classification and acts the same as zidovudine but is
used in patients who cannot tolerate zidovudine. Life threatening side effects are pancreatitis,
peripheral neuropathy, seizures, CAN depression, leukopenia, granulocytopenia,
thrombocytopenia and anemia. Other treatable side effects are nausea and vomiting, diarrhea,
abdominal pain, constipation, stomatitis, liver abnormalities, oral thrush and many more usually
resolve in a month. These drugs must be taken around the clock to maintain a therapeutic blood
level. Non-nucleoside Reverse Transcriptase Inhibitors (NNRTIS) a class of drugs which binds
directly to reverse transcriptase and blocks RNA, DNA conversion causing a disruption of the
enzyme site. Nevirapine is used in combination therapy along with other antiviral drugs. Side
effects include but are not limited to; rash, thrombocytopenia, fever, headache, nausea, hepatitis,
myalgia, etc. The patient must be instructed to report any rash immediately since a rash may
progress to Stevens-Johnsons syndrome, which may result in death. Delavirdine is in the same
class of drugs as nevirapine. This drug interferes with DNA synthesis that is needed for viral
replication. Some side effects of the drug are; fatal metabolic encephalopathy, blood dyscrasias
and acute renal failure. Common side effects are nausea and vomiting, headache, vaginitis, rash
and elevated LFT's. Again, this drug is used in combination therapy. Protease Inhibitors, another
class of drugs inhibits HIV protease, which prevents the maturation of the infectious virus.
Saquinavir is generally well tolerated because of low absorption rate. This is used in combination
with nucleoside analogues, NNRTIS and other protease inhibitors.

         Side effects are; pain, rash, diarrhea, buccal mucosa ulceration, abdominal pain, nausea,
parathesia, headache and hyperglycemia. This drug should not be used in children, pregnancy,
lactation and with caution in patients with liver disease. The patients must understand that
adherence to the drug regimes is extremely important since inadequate adherence can lead to
drug resistance and ultimately drug failure. There is little question that early detection is essential
to optimum therapeutic management. An obvious benefit of early detection would be corrective
treatment of other sexually transmitted diseases, tuberculosis and immunization against the onset
of OD and viruses. Lastly, it must be recognized that often life style issues and high-risk
behaviors have seriously damaged and weakened the AIDS patient's immune system and health
prior to onset of AIDS. Therefore, along with medication life style adjustment is an intricate part
of AIDS treatment. Cessation of risky behavior, abstinence from alcohol, tobacco and illegal
drugs is essential aspects of the treatment program. Additionally, it is believed that an
interdisciplinary approach incorporating acupuncture, massage therapy and other non traditional
remedies may be useful if only in raising the mental attitude of the patient. Interestingly AIDS
may be the vehicle for western medicine to entertain more seriously the various treatments of
non-traditional therapies, if only to underscores the relationship between health and a positive
attitude.




CONCLUSIONS :

        In 1985 AIDS was viewed as an immediate death sentence, and a horrific one at that, to
the infected person. There was apocalyptic terror that this epidemic could wipe out mankind.
Now, although there is still no cure for AIDS, education and other aggressive actions are
stemming the spread of the disease. On an individual basis, the length and quality of life of
people living with the AIDS virus is dramatically increasing. Medicine will ultimately conquer
AIDS and with the confidence of having done so, medical practitioners will be better prepared
and equipped to meet the next plague when and if it comes.

        **********************************************************************
Name:-       Dinesh Borikar

Roll No:-    51073

Semester:-   6th Sem. (Third Year)

Subject:-    Environment

Branch:-     Computer Technology

College:-    Rajiv Gandhi College Of Engineering, Research And
             Technology, Chandrapur.
Name:-       Jubi kunjumon

Roll No:-    51079

Semester:-   6th Sem. (Third Year)

Subject:-    Environment

Branch:-     Computer Technology

College:-    Rajiv Gandhi College Of Engineering, Research And
             Technology, Chandrapur.

				
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