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 Seen Environmental Learning Information Sheet No 5 2 • 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 Seen Environmental Learning Information Sheet No 5 3 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 Seen Environmental Learning Information Sheet No 5 4 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 Seen Environmental Learning Information Sheet No 5 5 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 . 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. 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. Seen Environmental Learning Information Sheet no 5 Health and the Environment Theme: Health and the Environment Topic No 5: Water Pollution Seen Environmental Learning Information Sheet