Chapter- 1-
Introduction to Pollution
ENVIRONMENTAL POLLUTION is normally taken to mean harm done to the natural environment by human activity. In fact, some environmental pollution can have natural sources, for example volcanic activity, which can cause major air pollution or water pollution and destroy flora and fauna. In terms of environmental issues, however, environmental pollution relates to human actions,especially in connection with energy resources. The demands of the industrialized nations for energy to power machines, provide light, heat, and so on are constantly increasing.The most versatile form of energy is electricity, which can be produced from a wide variety of other energy sources, such as the fossil fuels - coal, oil, and gas - and nuclear power produced from uranium.These are all non-renewable resources in addition,their extraction, transportation, utilization, and, and waste products, all give rise to pollutants of one form or another.The effects of these pollutants can have consequences not only for the local environment, but also at a global level.
Environmental issues
Matters relating to the detrimental effects of human activity on the biosphere, their causes, and the search for possible solutions Since the Industrial Revolution, the demands made by both the industrialized and developing nations on the Earth's natural resources are increasingly affecting the balance of the Earth's resources. Over a period of time, some of these resources are renewable - trees can be replanted,soil nutrients can be replenished – but many resources, such as fossil fuels and minerals, are non-renewable and in danger of eventual exhaustion. In addition, humans are creating many other problems which may endanger not only their own survival, but also that of other species. For instance,deforestation and air pollution are not only damaging and radically altering many natural environments, they are also affecting the Earth's climate by adding to the greenhouse effect and global warming, while water pollution is seriously affecting aquatic life,including fish populations, as well as human health.
WIDESPREAD EFFECTS OF POLLUTION
Many people think of air, water, and soil pollution as distinctly separate forms of pollution. However, each part of the global ecosystem - air,water, and soil - depends upon the others, and upon the plants and animals living within the environment.Thus, pollution that might appear to affect only one part of the environment is also likely to affect other parts.
For example, the emission of vehicle exhausts or acid gases from a power plant might appear to harm only the surrounding atmosphere. But once released into the air they are carried by the prevailing winds, often for several hundred kilometres, before being deposited as acid rain. This can produce an enormous range of adverse effects across a very large area, for example: increased acidity levels in lakes and rivers are harmful to fish stocks and other aquatic life;physical damage to trees and other vegetation results in widespread destruction of forest areas; increased acidity of soils reduces the range of crops that can be grown, as well as decreasing production levels; rocks such as limestone, both in the natural landscape and in buildings, are eroded - the effect of acid rain on some of the world's most important architectural structures is having disastrous consequences. In addition,acid rain in the form of aerosols or attached to smoke particles can cause respiratory problems in humans. Pollution of the Arctic atmosphere is creating Arctic haze- the result of aerosol emissions, such as dust, soot, and sulphate particles, originating in Europe.
ECOLOGY
Greek oikos `house´ Study of the relationship among organisms and the environments in which they live, including all living and nonliving components. The chief environmental factors governing the distribution of plants and animals are temperature, humidity, soil, light intensity, daylength, food supply, and interaction with other organisms. The term was coined by the biologist Ernst Haeckel in 1866. Ecology may be concerned with individual organisms (for example,behavioural ecology, feeding strategies), with populations (for example, population dynamics), or with entire communities (for example, competition between species for access to resources in an ecosystem, or predator-prey relationships).Applied ecology is concerned with the management and conservation of habitats and the consequences and control of pollution.
HABITAT
Localized environment in which an organism lives, and which provides for all (oral most all) of its needs. The diversity of habitats found within the Earth's ecosystem is enormous, and they are changing all the time. Many can be considered inorganic or physical; for example, the Arctic ice cap, a cave, or a cliff face. Others are more complex; for instance, a woodland or a forest floor. Some habitats are so precise that they are called microhabitats, such as the area under a stone where a particular type of insect lives. Most habitats provide a home for many species.Science of naming and identifying species, and determining their degree of relatedness. It plays an important role in preserving biodiversity; only a small fraction of existing species have been named and described.
BALANCE OF NATURE
In ecology, the idea that there is an inherent equilibrium in most ecosystems, with plants and animals interacting so as to produce a stable,continuing system of life on Earth.The activities of human beings can,and frequently do, disrupt the balance of nature.Organisms in the ecosystem are adapted to each other - for example,waste products produced by one species are used by another and resources used by some are replenished by others; the oxygen needed by animals is produced by plants while the waste product of animal respiration, carbon dioxide, is used by plants as a raw material in photosynthesis. The nitrogen cycle,the water cycle, and the control of animal populations by natural predators are other examples.
The idea of a balance of nature is also expressed in the Gaia hypothesis, which likens the Earth to a living organism, constantly adjusting itself to circumstances so as to increase its chances of survival.
FOOD CHAIN
In ecology, a sequence showing the feeding relationships between organisms in a particular ecosystem.Each organism depends on the next lowest member of the chain for its food. A pyramid of numbers can be used to show the reduction in food energy at each step up the foodchain.Energy in the form of food is shown to be transferred from autotrophs, or producers, which are principally plants and photosynthetic microorganisms, to a series of heterotrophs, or consumers. The heterotrophs comprise the herbivores, which feed on the producers;carnivores, which feed on the herbivores; and decomposers, which break down the dead bodies and waste products of all four groups (including their own), ready for recycling.In reality, however, organisms have varied diets, relying on different kinds of foods, so that the food chain is an oversimplification.
The more complex food web shows a greater variety of relationships, but again emphasizes that energy passes from plants to herbivores to carnivores. Environmentalists have used the concept of the food chain to show how poisons and other forms of pollution can pass from one animal to another, threatening rare species.For example, the pesticide DDT has been found in lethal concentrations in the bodies of animals at the top of the food chain, such as the golden eagle Aquila chrysaetos.
CONSERVATION
In the life sciences, action taken to protect and preserve the natural world, usually from pollution,overexploitation, and other harmful features of human activity. The late1980s saw a great increase in public concern for the environment, with membership of conservation groups,such as Friends of the Earth, Greenpeace, and the US Sierra Club,rising sharply. Globally the most important issues include the depletion of atmospheric ozone by the action of chlorofluorocarbons (CFCs), the build-up of carbon dioxide in the atmosphere (thought to contribute to an intensification of the greenhouse effect), and deforestation.Conservation groups in Britain originated in the 1860s; they include the Commons Preservation Society 1865, which fought successfully against the enclosure of Hampstead Heath (1865) and Epping Forest(1866) in London; the National Footpaths Preservation Society 1844 ; and the National Trust 1895. In the UK the conservation debate has centred on water quality, road-building schemes, the safety of nuclear power, and the ethical treatment of animals.
Twelve coastal sites in Great Britain,including five Special Areas of Conservation, have been designated by the European Commission to be part of a network of Natura 2000 sites. The EC will provide funds to help preserve these sites from development,overfishing, and pollution, and to monitor rare plants.They include the North Northumber land Coast, with its sea caves, its breeding population of grey seals in the Farne Islands,and Arctic species such as the wolf fish; the Wash and North Norfolk Coast, with its population of common seals,waders, and wildfowl, and its extensive salt marshes; and Plymouth Sound and estuaries, with their submerged sandbanks.
A £10 million project, `Turning the Tide´ was launched 1997 by the Millennium Commission. It would fund coastal restoration of Britain's only magnesium limestone cliffs between Hartlepool and Sunderland.The area is rich in wild flowers, with grassland and denes (steep, wooded valleys). Intensive farming and the use of fertilisers damaged the flora and fauna of the area. The beaches are polluted as a result of over two centuries of coal mining along the Durham coast. Waste from the mines was dumped into the sea and onto the beaches, leaving heaps of spoil 12 to 15 ft high. The restoration project is aimed at removing spoil from the beaches and returning the cliffs to their natural grassland.
NATURE RESERVE
Area set aside to protect a habitat and the wildlife that lives within it,with only restricted admission for the public. A nature reserve often provides a sanctuary for rare species. The world's largest is Etosha Reserve, Namibia; area 99,520sq km/38,415 sq mi.
ENDANGERED SPECIES
Plant or animal species whose numbers are so few that it is at risk of becoming extinct. Officially designated endangered species are listed by the International Union for the Conservation of Nature (IUCN). Endangered species are not a new phenomenon; extinction is an integral part of evolution. The replacement of one species by another usually involves the eradication of the less successful form, and ensures the continuance and diversification of life in all forms. However, extinctions induced by humans are thought to be destructive, causing evolutionary dead-ends that do not allow for succession by a more fit species. The great majority of recent extinctions have been directly or indirectly induced by humans; most often by the loss, modification, or pollution of the organism's habitat, but also by hunting for `sport´ or for commercial purposes.
According to a 1995 report to Congress by the US Fish and Wildlife Service, althoughseven of the 893 species listed as endangered under the US Endangered SpeciesAct 1968-93 have become extinct,40% are no longer declining in number. In February 1996, aprivate conservation group, Nature Conservancy, reported around 20,000 native US plantand animal species to be rare or imperilled.
According to the Red Data List of endangered species, published in 1996 by the IUCN,25% of all mammal species (including 46% of primates, 36% of insectivores, and 33% of pigs and antelopes), and 11% of all bird species are threatened with extinction.
An example of an endangered species is the Javan rhinoceros.There are only about 50 alive today and, unless active steps are taken to promote this species' survival, it will probably be extinct within a few decades.
Action by governments has been prompted and supplemented by private agencies, such as the World Wide Fund for Nature (formerly theWorld Wildlife Fund). In attempts to save particular species or habitats, a distinction is often made between preservation – that is, maintaining the pristine state of nature exactly as it was or might have been – and conservation, the management of natural resources in such a way as to integrate the requirements of the local human population with those of the animals, plants, or the habitat being conserved.
ECOTOURISM
Effects of tourism -The threat to conservationTourism is now the world's largest industry, generating over $2 billion every year. It isalso, potentially, one of the most damaging to the environment. Tourist developments often cause pollution, deplete scarce water resources, destroy natural habitats, and disturb wildlife.For example, marine turtles are currently threatened in some of their last European strongholds by beach developments; many national parks are now so heavily visited that people are threatening the very wildlife that the park is supposed to protect; sales of wildlife products to tourists is threatening some species with extinction; and producing host water in trekkers' accommodation in the Nepal Himalayas is causing serious timber shortages in places.
The cost to wildlife-The dusky seaside sparrow Ammodramus maritimus nigrescens,which lived in the Spartina bakerii-dominated salt marsh habitat on the east coast of Florida, became functionally extinct in the 1980s due mainly to habitat loss caused by tourist developments.Conservationists fear that African game parks are already suffering from overuse, and an industry representative is quoted as complaining that, at one time, 23 vehicles were surrounding one cheetah.
A possible solution Now, a new form of ecotourism is being developed, which aims to avoid the worst excesses of uncontrolled tourist development, and to play a positive role in conservation.Ecotourism is usually smaller-scale, relatively higher priced, and tailored specifically forpeople who want their holiday to be more than simply a laze on the beach. Ecotourism trips are designed to minimize the impact on the environment and, conversely, to provide local communities with a positive economic incentive for protecting wild habitats. A study in Cameroon, for example, showed that a standing natural forest would generate far more in terms of tourist earnings than it would if it were cut down for timber. Studies on `land value´ and tourism in the Monteverde Cloud Forest in Costa Rica have indicated a value of $1,250 perhectare. Ecotourism is already amajor industry in countries such as Costa Rica and Kenya.
SOCIAL CONCERNS
Most ecotourism initiatives also try to address social concerns. A sudden influx of tourists into a previouslyremote community can be culturally devastating, and ecotourists are usually encouraged to minimize these impacts by learning and respecting local cultural and religious norms, and by approaching communities in as sensitive a way as possible. Some national tourism authorities now publish posters or leaflets advising visitors of what to do or not to do,such as one advising on religious and cultural practices in Thailand. Well-designed ecotourism should also not conflict with sustainable land use, such as the collection of non-timber forest products in tropical rainforests,or local fishing activities.Real help for conservation efforts. Some holidays go even further, when tourists pay to go and work on conservation projects around the world. The visitor gets a great holiday, with the added excitement of taking part in activities aimed at protecting the natural environment .Local people have the chance to meet tourists in ways that are educative.