Health and the Environment: Water Pollution pot

Seen Environmental Learning Information Sheet No 5 1

The importance of water
The earth's surface is 75% water, but out of this
only 3% is fresh water, of which only 1% is
available for people to use. Water sustains life
for humans, animals and plants. People need
water for basic everyday activities like drinking
and cooking, but water is also very important for
the fuelling of agriculture and industry, and plays
an important role in the nature of national
economies.

However the supply of freshwater available to
humanity is shrinking. One of the main causes of
this is the polluting of many freshwater
resources. In some countries lakes and rivers
have become polluted with an assortment of
waste, including untreated or partially treated
municipal sewage, toxic industrial effluents,
harmful chemicals, and ground waters from
agricultural activities. Polluted water supplies not
only limit water availability but also put millions
at risk of water-related diseases.

The lack of freshwater is likely to be one of the
most critical natural resource issues facing
people in the next 50 years. The world's
population is expanding rapidly, yet our supplies
of freshwater are not, placing greater demand on

our water resources. This makes it even more
important that the remaining freshwater we have
is kept safe and clean.

Pollution problem
Pollution is everywhere. Few countries have
adequately safeguarded water quality and
controlled water pollution. Many countries do
not have standards to control water pollution
adequately, while others cannot enforce water
quality standards. The consequence of having
polluted water is:
•
A reduction in water quality which leads to
health problems
•
The endangerment of agriculture and
aquatic ecosystems.

Water pollution occurs when a body of water is
affected with large amounts of harmful
substances. When water is considered unfit for its
intended use, it is called polluted. There are two
types of water pollutants; point source and non-
point source. Point sources of pollution occur
when harmful substances are emitted directly
into a body of water, for example an instance
where there is an oil spill. A non-point source
delivers pollutants indirectly through
environmental changes, for example when

fertiliser from a field is carried into a stream by
rain.

Pollution of rivers and lakes reduces accessible
freshwater supplies. Each year roughly 450 cubic
kilometres of wastewater are discharged into
rivers, streams and lakes. To dilute and transport
this dirty water before it can be used again,
another 6,000 cubic kilometres of clean water are
needed - an amount equal to about two-thirds of
the world's total annual useable fresh water
runoff.

Pollution from untreated sewerage
In developing countries statistics suggest that
almost all sewerage that is deposited into rivers,
lakes and the ocean are untreated. This causes
significant health risks, as water carrying
untreated sewerage is a potential source of water-
borne disease. The effects can be far reaching, if
the water is used to grow crops that are then
eaten uncooked then disease can spread to a
whole community.

Underground pollution
Underground water supplies are particularly
susceptible to pollutants. Any pollutants that are
deposited underground can adversely affect water
supplies. Different pollutants include:
•

Landfill sites and rubbish dumps
•
Buried harmful waste e.g. Fuel tank
Water Pollution

Seen Environmental Learning Information Sheet no 5

Health and the Environment
Theme: Health and the Environment
Topic No 5: Water Pollution
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•
Industrial or mining waste
•
Human waste

Agricultural pollutants
Agriculture is the biggest polluter. In virtually
every country where agricultural fertilisers and
pesticides are used, they have contaminated
groundwater aquifers and surface waters. Animal
wastes are another source of pollution in some
areas.
The water that goes back into rivers and streams
after being used for irrigation is often severely
degraded by excess nutrients, salinity, pathogens,
and sediments that it is unfit for further use
unless cleaned by water purification plants which
is very costly.

Industrial pollutants
Wastes from industries have increased
enormously in recent decades. They not only
affect freshwater supplies and everything
dependent on them, but also marine life. Between
200 and 400 major chemicals are estimated to
contaminate the world's rivers. Industrial
pollutants, such as wastes from chemical plants,
are often dumped directly into waterways while
oils and salts are washed off city streets.

Pollutants such as sulphur dioxide and oxides of
nitrogen combine in the atmosphere to form
acid rain have had terrible effects on both
freshwater and land ecosystems. Acid rain lowers
the ph of rivers and streams. Unless buffered by
calcium (as contained in limestone), acidified
waters kill many acid-sensitive fish, including
salmon and trout. In the soil, acids can release
heavy metals, such as lead, mercury, and
cadmium, which can then infect water supplies.
Some of the worst pollutants are synthetic
chemicals. Some 70,000 different chemical
substances are in regular use throughout the
world. Every year an estimated 1,000 new
compounds are introduced. Many of them find
their way into rivers, lakes, and groundwater
aquifers.

A particular group of synthetic chemicals are an
immense threat, these are known as
persistent organic pollutants (pops):
•
DDT- this is an insecticide mainly used to
kill mosquitoes, flies, fleas, lice and
agricultural pests.
•
Dioxins- these chemical compounds occur
as a by-product of industrial processes like
paper bleaching, and also when plastics are
burnt.
•
PCB’s (polychlorinated biphenols)-
chemicals used to manufacture items like
transformers, pumps, plastics, paints and
adhesives.
They are long-lived and highly toxic in the
environment and not break down easily under
natural processes. Thus they tend to affect all
species up food chain, until they pose risks to
human health.

Water pollution in Namibia
Namibia has a very dry climate and therefore

does not have much fresh water. Water pollution
is a main concern to the country. With water
already being limited, Namibia cannot afford to
have any polluted waters. Pollution has become a
key issue since Namibia has become more
economically and industrially developed. This
means that more waste is generated, largely in
the form of deposited chemicals. Water pollution
in Namibia is largely of two types:
•
Toxic chemicals –pesticides, heavy metals
and chemicals
•
Organic material –largely sewage but also
silt and soil from run-off
Because of the low level of industrialisation in
Namibia, the latter are a more dangerous threat,
although the mining and leather tanning
industries can be major polluters at specific sites.
In Windhoek there are strict guidelines for the
type of industrial effluent that can be discharged
into the municipal sewer system and regular
inspections are carried out. Industries that may
produce heavily polluted effluent are also not
allowed within the drainage area where water is
reclaimed.

Theme: Health and the Environment
Topic No 5: Water Pollution
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A major threat to groundwater however comes
from rainwater flowing through landfill sites
where hazardous waste has been disposed of by
individuals and industry. Although special waste
disposal sites exist at Windhoek and Walvis Bay
they are not always used. Leachate from landfill
sites is usually more polluted than sewage and
more difficult to treat.

Sources of organic pollution include:
•
Dirty water around water points, seepage
from pit latrines or septic tanks
•
Animals around water points
•
Washing and bathing near a water source
•
Using the ‘bush’ toilet

Urbanization and population increases cause
more problems as they put more demand on fresh
water supplies and increase the risk of pollution.
Pollutants from industrial and economic
development threaten the survival of many
wildlife animals by contaminating and taking up
their water supply.

Pollution issues in the coastal zone

of the Erongo region
The pollution problems in the Erongo region are
associated with commercial and urban activities,
especially in and around the Walvis Bay harbour
area.

The fishing industry is a major polluter of the
seawater in Walvis Bay due to lack of discharge
treatment measures. Effluent wash water is led
directly into the sea where there is water intake
for the fish processing plants. Minor oil spills,
discharge of waste containing traces of anti-
fouling paints, sewage from ships and heavy
metals from the export of semi-processed mine
ore, also contribute to the pollution of the sea
water in the harbour and bay area.

Solid waste, sewerage and small amounts of oil
products produced at the ships are occasionally
dumped into the sea resulting in wastes being
washed ashore on the beaches between Walvis
Bay and Swakopmund and in the port of Walvis
Bay.

The waste dumpsite at Walvis Bay may pollute
the ground water as the water table at the site
coincides with the lower level of the dump.
Underground pollution may also occur from the
Rössing uranium mine. However, the mine has
developed an extensive programme for

wastewater recovery. Moreover, monitoring
operations in the vicinity of the mine seems to
secure that potentials impacts on the surrounding
nature is minimal.

Lack of environmental awareness among some
local residents and holiday visitors causes
littering of the beaches and the desert, i.e. Plastic
bags, paper, cans, bottles and fishing lines.

Legislation in Namibia
Currently the Walvis Bay-based Environmental
Action Trust (EAT) of Namibia is tackling
government on its legal responsibilities for
pollution around harbours. There is also
legislation from 1956 and 1958 that, along with
the Sea Fisheries Act of 1992, places the
responsibility for protecting Namibia's harbours
and fishing grounds from pollution with the
government. A polluter can be fined up to N$1-
million and/or face 15 years in jail. The 1958
legislation also guards against effluent being
discharged into the sea, including toxic paint
being scraped off or applied at the harbour's
syncrolift. The sea fisheries act of 1992 makes it
illegal to dump anything "injurious to fish, fish
food or aquatic plants", to disturb "the ecological
balance in any area of the sea", or to "wilfully or
negligently pollute any water including the sea".
Currently three government ministries have been

charged with ignoring parts of these laws!

Some argue that stronger legislation and
enforcement measures are required to ensure that
the principle of the ‘polluter paying’ is fully
implemented. This principle recognises that the
polluter should pay for any environmental
damage created and that the burden of proof for
showing that a particular technology is safe lies
with the developer, not the general public.
Unfortunately as experience with the Ramatex
textile factory has shown, because of inadequate
controls, it is often unclear how much pollution
has been caused or whether enforcing the
Municipal regulations is practically possible.
Theme: Health and the Environment
Topic No 5: Water Pollution
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Conclusion
Overuse and pollution of the world's freshwater
resources are a recent development. Their long-
term consequences are still unknown. Already,
however, they have taken a heavy toll on the
environment, and they pose increasing risks for
many species. Polluted water and lack of
sanitation also greatly risk human health.
Moreover, the state of freshwater resources
contributes to the deterioration of coastal waters

and seas. It is therefore critical that more care is
taken to reduce pollutants in our fast retreating
freshwater supplies.


Theme: Health and the Environment
Topic No 5: Water Pollution
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Important ideas to stress in your teaching and learning
•
The earth’s supply of freshwater is limited. Providing clean water to all is likely to be the biggest
environmental challenge in the 21st century.
•
Water pollution by sewage, toxic industrial effluents, harmful chemicals, and ground waters from
agricultural activities limit water availability and spread water-related diseases.
•
Water is scarce in Namibia so preventing water pollution is a major priority. Most water pollution
is from organic waste.
•
Water pollution is best prevented –through education and legislation that implements and monitors
the ‘polluter pays’ principle because the costs of treating polluted water are very high.


Glossary
Ecosystem A group of interdependent organisms together with the environment they
inhabit and depend on.
Effluent Liquid waste discharges from a sewage system, factory, nuclear power station,
or other industrial plant.
Industrialisation The adoption of industrial methods of production and manufacturing by a

country, with all the associated changes in lifestyle, transport, and other aspects
of life.
Legislation A law or laws passed by an official body, especially a governmental assembly.
Organic Relating to or derived from living things.
Pesticide A chemical substance used to kill pests, especially insects.
Pollution Things that pollute or cause harm to an area of the natural environment, for
example, chemicals or waste products that contaminate the air, soil, or water.
Urbanisation The accustoming of somebody to living in a town or city rather than in the rural
areas, and the causing of people to migrate to a town or city from the rural
areas.


Sources/Further Reading
Water Pollution, National Water Awareness Campaign
The Gaia Atlas of Planet Management
The Guardian August 22 2003