Реферат на тему Water Essay Research Paper Most living things
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Water Essay, Research Paper
Most living things are made up of water, and a healthy lifestyle requires clean water. So if a planet is to sustain life, it is important for us to ensure that our most valuable resource is not taken for granted. While we cannot survive without water, it can also be the carrier of disease and even death if it is polluted. Human modification of the natural environment is an ancient phenomenon. It has been estimated that around 75 percent of the habitable land on the planet has been disturbed to some degree. (Greenpeace, 98) Increasing population levels, increasing industrial activity, and more extensive agriculture have accompanied this disturbance. The world does have a reliable supply of fresh ground water as long as we don’t contaminate or overuse it, as it replenishes slowly. Water covers approximately 71 percent of the earth’s surface, but less than 3 percent is accessible ground water, lakes and waterways, moisture in the soil and water vapour. (Study Guide, 1998) It has become quite clear that both water quality and quantity influence issues involved with health. It is my opinion that humans cause the major problems, which are over population, surface water run-off, and industrial waste. HISTORICAL OVERVEIW This is a brief historical review of drinking water. This review will embrace three periods that seem to set out significant changes in approaches to producing acceptable drinking water. I have characterised these periods as follows: The ancient period The ancient period covered a time when most population groups depended upon individual initiatives for the quality of the water consumed. The progressive period The progressive period, which began about 1880, was characterised by rapid improvement in and wide acceptance of water treatment technology, control of water born diseases, and passage of national legislation and promulgation of standards designed to assure safe drinking water. The contradictive period The contradictive period was fashioned from the industrial progress that accompanied World War II, but its impact on drinking water was not recognised until the 1960s. (Speidel, H. 1998) THE PROBLEMS Industrialisation One of the more notable consequences of the technological development in the Twentieth Century is the pollution of the global environment of thousands of chemicals that are all products manufactured to benefit humans. The pollution comes from industrial toxic chemicals, burning of coal, oil, and other fuels by power plants. Also, from factories, automobiles produce sulfur and nitrogen oxides, which can cause acid rain. Thermal pollution is caused using water to cool machinery, which heats up the water and is then returned to the water source. (The Pollution Solution, 1998) More than 300 billion gallons of water are withdrawn from America’s lakes, rivers, and streams each day. Of this quantity 91 percent is devoted to industrial use, an amount of water roughly equal to the 75 percent of the daily Mississippi River at its mouth. While some water is evaporated, or is incorporated into the product itself, most is discharged back to its source. This water, usually altered considerably in the industrial process, may contain contaminants that degrade water quality and pose a threat to human health. Degradation of water quality comes about the addition of large amounts of nutrients, suspended sediments, bacteria, and oxygen demanding matter. The possible additions of toxic pollutants are particularly important because of their persistence, harmful effects at low concentrations, and ability to enter the food chain. (Speidel, H. 1998) Over population As the population grows, so does the need to supply drinking water. It is not only drinking water that is in demand, agriculture irrigation consumes 80 percent of the water in the world. (Centre of Health and the Global Environment, 1998) Live stock is also another consumer of water along with the over pumping of ground water, which has a recharge rate that is extremely slow. The water supply issue is one that has been recognised by many parts of the world, including Australia. The 1960’s in Australia were drought years. It was a common and accepted fact that water restrictions were used within most cities. It wasn’t until the Warragamba Dam was built that there was plenty of water for the city. Water was cheap, and there was no reason for not wasting it. The city began to expand and it has been ever since. Sydney’s population in 1990 was 3.6 million and by 2011 it is forecast to rise to 4.5 million. (Cairnes, L. 1993) By looking at those figures, it is quite evident the Sydney must start to plan strategies for the reduction of water consumption. Because cities like Sydney are constantly increasing in size, there are bound to be health hazards involved with the water system. Drought is a large problem in a lot of third world counties such as South Asia and Africa, which leads to health hazards like malnutrition. Even though malnutrition is manly due to economic circumstances, overpopulation contributes largely to the problem. (Frontline, 1998) When there is a water shortage within a large quantity of people, humans are not the only species affected. Livestock also suffer immense amounts of nutritional problems. Health problems involved with nutritional deficiencies in livestock can be: loss of weight, weakness and decreased ability to forage or walk for long distances, starvation and death, pregnancy toxaemia and milk fever, reduced abilities to fight of infections and maintain health, and the death of newborn animals. (Animal health in drought, 1998) Even though this is very tragic for the animals, their illnesses are also passed onto humans. Whether it is through eating the livestock or drinking contaminated water that had been in contact with the livestock.
A recent disease crisis in Sydney may have been through the fault of a contaminated animal entering the water system. The managing director of Sydney Water, Mr Chris Pollett, said the cause of the prospect contamination was unknown. It was either contamination from a dead animal, a failure of the plants filtration system, or a combination of both. (Contaminated: Water crisis grips Sydney, 31-7-98) One million of Sydney’s Waters 1.6 million households were hit by the outbreak. This simply demonstrates how quickly a water disease can spread through a large population of people. Surface water run – off Most people believe that the largest source of water pollution comes from a pipe, which originates from factories and sewage treatment plants. But the fact is that the largest source of water pollution in rivers, lakes and streams does not come from a pipe, but from surface run off. (Surface Water Run -off, 1998) This type of pollution is sometimes called “non – point source” pollution because it comes from a variety of sources, not from a single discharge pipe. When it rains, water washes over drive ways, roofs, agricultural lands, streets, lawns, construction sites, and logging operations picking soil, garbage and toxins. The amount of pollution carried by rainwater, melted snow and irrigation water flowing into streams and lakes, and through the soil into ground water is much larger than pollution from industry. A report conducted by the Minnesota Pollution Control Agency reveals that the Minnesota River is one of the 20 most endangered waterways in America. The biggest pollution problem it faces is non-point source pollution, manly caused by the agricultural community. (Minnesota River Basin Agricultural Resources and Research, 1998) Polluted run-off causes damage to fish, wildlife and their habitat; damages water supplies, (which in turn effects humans health when drinking water is contaminated) promotes excessive weed growth and degrades scenic beauty and recreational opportunities. Pollution from surface run-off is hard to detect and control because it doesn’t come from a single source like a factory or sewage treatment plant. Instead, many everyday activities and traditional land use practices destroy aquatic habitat by causing soil erosion, stream overheating and by allowing pollutant to wash into our waters. ENVIRONMENTAL IMPACTS I think that the biggest environmental impact humans have on water is the destruction of the oceans. The oceans are home to an immense diversity of life. They are also a global commons with an important role in maintaining the planet’s life support processes and in providing resources, transportation and ecological services for all. The oceans receive pollutants from all land areas and from at sea activities (Eg. vessel-source pollution, offshore oil and gas facility discharges, ocean dumping) and the coasts have historically been the sites for intensive human development, concentrating the effects of human activities on beaches, wetlands, bays, coastal lagoons, mangroves, coral reefs and coastal waters. (Greenpeace, 1998) The biggest health issue involved with the pollution of our oceans is seafood. According to the New South Wales Environment Protection Authority, seafood and fish grown in, or harvested from, water subject to discharges of environmental contaminants or polluted surface run-off, have been public health concerns. A survey of seafood and fish sold in the market place was conducted by New South Wales Health from 1989 to 1993 to determine the levels of heavy metal residues such as mercury, cadmium, copper, lead and zinc. Zinc was found to be the most common pollutant found in the seafood, but traces of other metals where still found. (Environment protection Authority, 1998) These environmental factors can affect food safety and, consequently, public confidence in certain food industries and the food supply in general. SOCIAL IMPACTS In recent years, public attitudes to environmental problems have been changing rapidly in many parts of the world. One reason for this is that people are aware of the capacity humans have to change their environment. The nuclear bomb has been a potent symbol of this capacity for many people. Other awakenings such as the recent giardia scare in Sydney have also got people thinking about the environment in which they live. Increasingly, exposure to industrial toxins through routes such as fish consumption and drinking water have emerged as significant threats to human health. Other social traditions such as swimming, other water sports and recreation type activities also pose a threat to human health. Cleaner water has also been good for business. Beaches, rivers and lakes are the top vacation destinations, Americas recreation and tourism industry is worth more than $380 billion per year. (Water Report, 1998) When a resource begins to show physical signs of abuse, economic and ecological consequences are usually not far behind. Water’s seeming ubiquity has blinded society to the need to manage it sustainably and to adapt to the limits of a fixed supply. Failure to take notice of the water pollution problems that surround us, will result in a threat to hour economic status. CONCLUSION Now is the time for us to require the best treatment that technology can provide to protect the public from the myriad of toxic chemicals we have discharged to our environment and that ultimately find there way into our water supplies. I believe now is the time the Australian public, its legislators, and its regulators to say we are not going to play Russian roulette with our health and the future posterity of this nation.