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

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

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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

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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

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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

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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

inhabit and depend on

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

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