POLLUTION: almost all forms of life inPOLLUTION: almost all forms of life in



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Pollution is a by product
of the increasing human population, our affluent lifestyle, industrialisation
and concentration in cities. A few of the more significant pollution threats
are described below.

Pesticides and

Chlorinated hydrocarbon
like DDT(refer appendix 1) and dieldrin were once widely used and have been
shown to cause significant problems as they accumulate through the food chain.

Oil spills

These give rise to major
problems when large transport tankers spill huge quantities at sea killing
marine life.(refer appendix 2)

Acid rain

The ph of lakes and
rivers has fallen as rain dissolves sulphur and nitrogen oxides emitted from
the smoke stacks of industrialised cities. Falling ph levels killed almost all
forms of life in some lakes across north America and Europe. (refer appendix 3)


Over Antarctica there is
an “ozone hole” which has been growing each year that observation have been
taken. Ozon protects us and all forms of life from UV radiation. It has been
estimated that for every 1 per cent drop in atmospheric ozone there is 5-6 per
cent increase in skin cancer. The main chemicals implicated in this destruction
of the ozone are chlorofluorocarbon(CFCs) which have been widely used since the
1920s in cooling system and fire extinguishers.(refer appendix 4)

Heavy metal

Industrial pollutants
include heavy metals like mercury, cadmium and arsenic and these have been
shown to cause a major loss of life in the aquatic environment.(refer appendix


Whilst nuclear power is
extremely efficient, two major problem seem to be associated with its use:

threat of nuclear accident, as happened at Chernobyl in Ukraine in 1986. It is
estimated that up to 70000 people will die from cancer associated with the
radioactive poisoning from this catastrophe.(refer appendix 6)

dumping of radioactive waste. Countries around the world are examining the
possibilities of using Australia as a suitable dumping site.(refer appendix 7)

detergents, sewage

Run off found in these
sources, containing high levels of nutrients with nitrates and phosphate, has
been shown to destroy many waterways by either direct poisoning or promoting
excess algal, plant growth, leading to the choking of waterways or destruction
of marine beds.

Air pollution







The permanent destruction
of indigenous forest and woodlands. It is a major problem all over the world
particularly high in tropics. Recent and present deforestation affects mainly
tropical rain forest. As the amount of deforestation increases, the
biodiversity will decrease.


Logging is normally log
the plant for wood purpose. They will plant back the tree again.


It is a huge store of
carbon. It is a habitat for animal and many plants. It also conserve soil
nutrient. Prevent large scale erosion. It is an estatic value. It is also an
large gene pool of plant resources.


Increase in land

This causes local
extinction of species of trees. The need to sustain the increase of demand due
to growth in human population

Affects diversity

It removes or affect the
bases of food web. Removes the habitat of many other species. Causes local
extinction of many other species. Causes local extinction of many other
species. The number of species or individuals decreases. Lower biomass and
productivity per hectare.

Affects carbon and
nitrogen cycle

Causes less
photosynthesis. Less carbon dioxide is removed and more is added into
atmosphere. Decomposing fungi live in association with the roots of tree.



The conservation of
species in their natural habitats. The most appropriate way of conserving
biodiversity. It also conserving the area where population of species exist
naturally is an underlying condition for the conservation of biodiversity.


The preservation of
components of biological diversity outside their natural habitats. It provides an
“insurance policy” against extinction. Maintain domesticated plants which
cannot survive in mature unalded. Provide excellent research opportunities on
the components of biological divertical. Institutions play s central role in
public education and awareness raising by bringing members of the public into
contract with plants and animals they may not normally come in contact with.
Example of method, gene banks (seed banks, sperm, ova banks, field banks), in
vitro plant tissue and microbial culture collections, captive breeding of
animals and artificial propagation of plants with possible reintroduction into
world, collecting living organisms foe zoos, aquarca and botanic gardens for
research and public awareness.



 Eutrophication is when the environment becomes
enriched with nutrients.

All living things need
specific nutrients to live. Because too many or too few can cause problems,
nature does a good job of providing the right amount of nutrients. This is true
in aquatic ecosystems because aquatic ecosystems are so dynamic. the water is
oligotrophic when too few nutrients are present. It makes sense that serious
problems will arise when there is not enough nutrition available for the
variety of organisms living in an aquatic environment.

However, problems can
also arise when the aquatic system has an overabundance of nutrients. We get
eutrophication when this happens. When too many nutrients, like nitrogen and
phosphorous, are present a eutrophic stream, river or lake occurs. usually as a
result of runoff from the surrounding land. Algae, plankton and other
microorganisms love these types of nutrients, and when they are plentiful,
these aquatic organisms can take over. It can have serious negative effects on
other organisms like birds, fish and even people, when river, lake or other
aquatic system becomes eutrophic.


Excess of fertiliser from
agriculture land washed away by the rain water to the nearby pond  or water. The nutrient level in water increases
when accumulation of fertilisers in the water happens. This phenomena is called
eutrophication. This causes phytoplankton to grow and reproduce more rapidly.
This will result in algal blooms. The aquatic plants cannot carry out
photosynthesis because the sunlight is blocked by the algae. Sediment at the
bottom of the pond is formed when the aquatic plants and the algae die. This
effects the pond’s ecosystem and encourage the growth of detritus. All the
oxygen the water s used up by the detritus by carrying out decomposition. This
causes the biochemical oxygen demand(BOD) increases. Lack of oxygen in water
causes many aquatic organisms to die. Toxic bi-product that can poison the
ecosystem of the pond are produce by some species of algae.



A sample of water
is taken from a pond.

If the amount of
oxygen required for the decomposition of organic matter in the sample is high,
then BOD is high. This means the water sample from the pond is very highly

BOD increases when
the water is very highly polluted by bacteria pollution.

BOD decreases when
the water is very highly polluted by toxic pollution.





(nitrates and phosphates)

Human actions causes
eutrophication. Human likes to depend on the usage of nitrate and phosphate
fertilizers. Lawns, golf courses, farm and other fields are to be heavily
fertilized by people. These fertilizers run off into streams, rivers, lakes and
oceans when it rain. The hungry algae, plankton and other aquatic plant life
are fed well. This increases the rate of photosynthesis activity. This causes
dense growth of plant life such as the water hyacinths and algal blooms in the
aquatic environments.

animal feeding operations

Main contributor of nitrogen
and phosphorus nutrients responsible for eutrophication is the concentrated
animal feeding operations (CAFOs). The concentrated animal feeding operations
normally discharge high scores of the nutrients. It somehow finds way into lakes,
streams, rivers, and oceans where they accumulate in very high concentrations. By
recurring cyanobacterial and algal blooms, thereby plaguing the water bodies.

Direct sewage
discharge and industrial waste into water bodies

In the developing
nations, sewage water is directly channel into water bodies such as oceans,
lake, and rivers. This results in, high amounts of chemical nutrients introduced.
This stimula the dense growth of other aquatic plants and algal blooms which
threatens survival of aquatic life in a lot of ways.


A technique of growing
fish, aquatic plants without soil and shellfish in water containing dissolved
nutrients is known as aquiculture. Aquiculture it also qualifies a top ranking
contributor to eutrophication as it is highly practice in the recent times. The
unconsumed food particles together with the fish excretion will increase the
levels of phosphate and nitrogen in the water if aquiculture is not properly
managed. This will result in dense growth of microscopic floating plants.

Natural events

Eutrophication can also
cause by natural events. If a lake, river, or stream flood, it may wash away
any excess nutrients off the land and into the water. However, in areas that
are not surrounded by fertilized lands, eutrophication is less likely to occur.


 Lake Erie was the most
publicized example of eutrophication in the 1960s and 1970s. it was called the
“dead lake”. From heavily developed agricultural and urban lands, the
smallest and shallowest of the five Great Lakes was swamped for decades with
nutrients. Plant and algae growth choked out most other species living in the
lake as a result. It  left the beaches unusable because of the smell of
decaying algae that washed up on the shores. (refer appendix 8)




Eutrophication can have
serious, long-term effects. Algal
blooms is the most notable effect of eutrophication. When a bloom
occurs, the stream, river, lake or ocean becomes covered with algae, which is
usually bright green. In addition to looking terribly ugly, it also blocks
light from reaching the water. This prevents the aquatic plants from
photosynthesizing, a process which provides oxygen in the water to animals that
need it, like fish and crabs.

Threatens the
survival of fish and other aquatic life forms

The other photosynthetic
plants and phytoplankton grow explosively when aquatic ecosystems experience
increase in nutrients. This is commonly known as algal blooms. This causes the
algal blooms to limit the amount of oxygen dissolved which is required for
respiration by other plant and animals species in the water. When the algae or plant
life die and decompose, oxygen depletion will occur. When hypoxic levels is
reached by the dissolve oxygen, the plant and animal species under the water
such as fish, shrimp, and other aquatic species suffocate to death. In extreme
cases, the growth of bacteria is encouraged by the anaerobic conditions that
produces toxins which are dangerous to the marine bird and mammals. Light
penetration into the lower depths of the water is reduced because of the growth
of phytoplankton. This causes loss of aquatic life, aquatic dead zones and it
also lessens biodiversity.

Deterioration of
water quality and limits access to safe drinking water

Algal blooms are highly
toxic. The growth of more toxic bacterial is promoted when the water reaches
the anaerobic condition. This causes decline in the availability of clean
drinking water and extensive deterioration of water quality. Water systems is
block because of the dense growth of photosynthetic bacteria and algal bloom on
the surface of water. Hence, this limit the availability of piped water. Regardly,
toxic algal blooms have shut down many water supply systems across the world. For
example, in 2007, more than 2 million residents of Wuxi, China could not access
piped drinking water for more than a week because of the severe attack by algal
blooms on Lake Taihu. (refer appendix 9)

Endangers fishing

Increased growth of
minute floating plants such as photosynthetic bacteria and algae and the growth
of extensive and dense mats of floating plants such as water hyacinths and Nile
cabbage is one of the main characteristic of eutrophication. Fishing is
endangered whenever this happens on a water body. It will become difficult to
set the fishing nets in water when the plants are floating on water. This will
also limit the mobility of boats and other fishing vessels.

Degradation of
recreational opportunities

The blooming of other
aquatic plants and algal that float on an extensive area of the water surface
is the main problem of eutrophication. It reduces the navigation and
transparency in the water which lessens the recreational values and
opportunities of the lakes, especially for swimming and boating. Water hyacinth,
algal blooms, and Nile cabbage can spread over an extensive area along the
shores. It can sometimes float over the whole surface into the land area.

Poisoning and
impact on human health

Dinoflagelates which
generates red tide is also referred as cyanobacteria, which release very
powerful toxins with high poison levels in the water. Explosive plant growth in
the water create anaerobic conditions which also results in the doubling of the
toxic compounds. Even at the least concentration when ingested in drinking
water, it causes death in animals and humans. Various negative health impacts
such as cancers can be cause when the toxic compounds can also make their way
up the food chain. Biotoxins are linked to increased diarrhoetic shellfish,
paralytic and incidence of neurotoxic in humans. This can lead to death. The
poison is accumulated in their muscles by shellfish and then poison humans upon
consumption. The ability of inhibiting blood circulation in infants is
associated with high nitrogen concentration in drinking water. This is a
condition known as blue baby syndrome. 



Use of nitrate and
phosphate fertilizers is the main cause of eutrophication. Composting can be used as a solution, in a bid to
address the phenomenon. The practice of converting organic matter such as
decaying vegetation and food residues into compost manure is known as composting. The high concentration of phosphates and
nitrates that feed the other microbes and algae in water bodies are the
deficient caused by the nutrients present in the compost manure. All the
essential elements are synthesized and broken down by the plants in compost
fertilizer thereby not creating the cycle of eutrophication. Nutrient
limitation is a term for this method of controlling eutrophication.

Reducing pollution

Limiting pollution is an effective
and easy method of cutting back on the amount of phosphate and nitrogen discharged
into water systems. Municipalities and big manufacturing companies ought to desist
from discharging waste into water systems and reduce pollution. So this will reduce
the amount of nutrients and toxins ending up in the waters that feed the other
microscopic organisms and algae. Nutrient content will be reduced in the water
systems if municipalities and industries can cap their waste discharge and
pollution to a lower level which can subsequently control eutrophication.


The use of ultrasonic
irradiation is one such mechanism which has been exploited as an alternative
solution to manage and control algal blooming when it comes to eutrophication. Cavitations
is used to produces free radicals that destroy algae cells in this process. To determine
the uniqueness of its use in controlling the eutrophication problem, research
is still underway.