11.2 WATER POLLUTION
Water pollution is any chemical, physical or biological change in the quality of water that has a harmful effect on any living thing that drinks or uses or lives (in) it. When humans drink polluted water it often has serious effects on their health. Water pollution can also make water unsuited for the desired use.
Comprising over 70% of the Earth’s surface, water is undoubtedly the most precious natural resource that exists on our planet. Without the seemingly invaluable compound comprised of hydrogen and oxygen, life on Earth would be non-existent: it is essential for everything on our planet to grow and prosper. Although we as humans recognize this fact, we disregard it by polluting our rivers, lakes, and oceans. Subsequently, we are slowly but surely harming our planet to the point where organisms are dying at a very alarming rate. In addition to innocent organisms dying off, our drinking water has become greatly affected as is our ability to use water for recreational purposes. In order to combat water pollution, we must understand the problems and become part of the solution.
According to the American College Dictionary, pollution is defined as: to make foul or unclean; dirty. Water pollution occurs when a body of water is adversely affected due to the addition of large amounts of materials to the water. When it is unfit for its intended use, water is considered polluted. Two types of water pollutants exist; point source and nonpoint source. Point sources of pollution occur when harmful substances are emitted directly into a body of water. The Exxon Valdez oil spill best illustrates a point source water pollution. A nonpoint source delivers pollutants indirectly through environmental changes. An example of this type of water pollution is when fertilizer from a field is carried into a stream by rain, in the form of run-off which in turn effects aquatic life. The technology exists for point sources of pollution to be monitored and regulated, although political factors may complicate matters. Non-point sources are much more difficult to control. Pollution arising from non-point sources accounts for a majority of the contaminants in streams and lakes.
Many causes of pollution including sewage and fertilizers contain nutrients such as nitrates and phosphates. In excess levels, nutrients over stimulate the growth of aquatic plants and algae. Excessive growth of these types of organisms consequently clogs our waterways, use up dissolved oxygen as they decompose, and block light to deeper waters. This, in turn, proves very harmful to aquatic organisms as it affects the respiration ability or fish and other invertebrates that reside in water.
The pollution of rivers and streams with chemical contaminants has become one of the most crucial environmental problems within the 20th century. Waterborne chemical pollution entering rivers and streams cause tramendous amounts of destruction.
Pathogens are another type of pollution that prove very harmful. They can cause many illnesses that range from typhoid and dysentery to minor respiratory and skin diseases. Pathogens include such organisms as bacteria, viruses, and protozoan. These pollutants enter waterways through untreated sewage, storm drains, septic tanks, runoff from farms, and particularly boats that dump sewage. Though microscopic, these pollutants have a tremendous effect evidenced by their ability to cause sickness.
The major sources of water pollution can be classified as municipal, industrial, and agricultural. Municipal water pollution consists of waste water from homes and commercial establishments. For many years, the main goal of treating municipal wastewater was simply to reduce its content of suspended solids, oxygen-demanding materials, dissolved inorganic compounds, and harmful bacteria.
In recent years, however, more stress has been placed on improving means of disposal of the solid residues from the municipal treatment processes. The basic methods of treating municipal wastewater fall into three stages:
² primary treatment, including grit removal, screening, grinding, and sedimentation;
² secondary treatment, which entails oxidation of dissolved organic matter by means of using biologically active sludge, which is then filtered off;
² and tertiary treatment, in which advanced biological methods of nitrogen removal and chemical and physical methods such as granular filtration and activated carbon absorption are employed.
The handling and disposal of solid residues can account for 25 to 50 percent of the capital and operational costs of a treatment plant.
The characteristics of industrial waste waters can differ considerably both within and among industries. The impact of industrial discharges depends not only on their collective characteristics, such as biochemical oxygen demand and the amount of suspended solids, but also on their content of specific inorganic and organic substances. Three options are available in controlling industrial wastewater. Control can take place at the point of generation in the plant; wastewater can be pretreated for discharge to municipal treatment sources; or wastewater can be treated completely at the plant and either reused or discharged directly into receiving waters.
Raw sewage includes waste from sinks, toilets, and industrial processes. Treatment of the sewage is required before it can be safely buried, used, or released back into local water systems. In a treatment plant, the waste is passed through a series of screens, chambers, and chemical processes to reduce its bulk and toxicity. The three general phases of treatment are primary, secondary, and tertiary. During primary treatment, a large percentage of the suspended solids and inorganic material is removed from the sewage. The focus of secondary treatment is reducing organic material by accelerating natural biological processes. Tertiary treatment is necessary when the water will be reused; 99 percent of solids are removed and various chemical processes are used to ensure the water is as free from impurity as possible.
Agriculture, including commercial livestock and poultry farming, is the source of many organic and inorganic pollutants in surface waters and groundwater. These contaminants include both sediment from erosion cropland and compounds of phosphorus and nitrogen that partly originate in animal wastes and commercial fertilizers. Animal wastes are high in oxygen demanding material, nitrogen and phosphorus, and they often harbor pathogenic organisms. Wastes from commercial feeders are contained and disposed of on land; their main threat to natural waters, therefore, is from runoff and leaching. Control may involve settling basins for liquids, limited biological treatment in aerobic or anaerobic lagoons, and a variety of other methods.
Ninety-five percent of all fresh water on earth is ground water. Ground water is found in natural rock formations. These formations, called aquifers, are a vital natural resource with many uses. Nationally, 53% of the population relies on ground water as a source of drinking water. In rural areas this figure is even higher. Eighty one percent of community water is dependent on ground water. Although the 1992 Section 305(b) State Water Quality Reports indicate that, overall, the Nation’s ground water quality is good to excellent, many local areas have experienced significant ground water contamination. Some examples are leaking underground storage tanks and municipal landfills.
There are several classes of water pollutants. The first are disease-causing agents. These are bacteria, viruses, protozoa and parasitic worms that enter sewage systems and untreated waste.
A second category of water pollutants is oxygen-demanding wastes; wastes that can be decomposed by oxygen-requiring bacteria. When large populations of decomposing bacteria are converting these wastes it can deplete oxygen levels in the water. This causes other organisms in the water, such as fish, to die. A third class of water pollutants is water-soluble inorganic pollutants, such as acids, salts and toxic metals. Large quantities of these compounds will make water unfit to drink and will cause the death of aquatic life.
Another class of water pollutants are nutrients; they are water-soluble nitrates and phosphates that cause excessive growth of algae and other water plants, which deplete the water's oxygen supply. This kills fish and, when found in drinking water, can kill young children.
Water can also be polluted by a number of organic compounds such as oil, plastics and pesticides, which are harmful to humans and all plants and animals in the water.
A very dangerous category is suspended sediment, because it causes depletion in the water's light absorption and the particles spread dangerous compounds such as pesticides through the water.
Finally, water-soluble radioactive compounds can cause cancer, birth defects and genetic damage and are thus very dangerous water pollutants.
126.96.36.199 DIRT AND SEDIMENT OR TURBIDITY
Most waters contain some suspended particles which may consist of fine sand, clay,soil, and precipitated salts. Turbidity is unpleasant to look at, can be a source of food and lodging for bacteria, and can interfere with effective disinfection.
188.8.131.52 TOTAL DISSOLVED SOLIDS
These substances are dissolved rock and other compounds from the earth. The entire list of them could fill this page. The presence and amount of total dissolved solids in water represents a point of controversy among those who promote water treatment products.
184.108.40.206 TOXIC METALS OR HEAVY METALS
Among the greatest threats to health are the presence of high levels of toxic metals in drinking water - Arsenic, Cadmium, Lead, Mercury, and Silver. Maximum limits for each are established by the EPA Primary Drinking Water Regulations. Other metals such as Chromium and Selenium, while essential trace elements in our diets, have limits imposed upon them when in water because the form in which they exist may pose a health hazard. Toxic metals are associated with nerve damage, birth defects, mental retardation, certain cancers, and increased susceptibility to disease.
Asbestos exists as microscopic suspended mineral fibers in water. Its primary source is asbestos-cement pipe which was commonly used after World War II for city water supplies. It has been estimated that some 200,000 miles of this pipe is presently in use to transport our drinking water. Because these pipes are wearing, the deadly substance of asbestos is showing up with increasing frequency in drinking water. It has been linked with gastrointestinal cancer.
Even though trace amounts of radioactive elements can be found in almost all drinking water, levels that pose serious health hazards are fairly rare--for now. Radioactive wastes leach from mining operations into groundwater supplies. The greatest threat is posed by nuclear accidents, nuclear processing plants, and radioactive waste disposal sites. As containers containing these wastes deteriorate with time, the risk of contaminating our aquafiers grows into a toxic time bomb.
220.127.116.11 TASTES AND ODORS
If your water has a disagreeable taste or odor, chances are it is due to one or more of many organic substances ranging from decaying vegetation to algae; hydrocarbons to phenols. It could also be TDS and a host of other items.
18.104.22.168 PESTICIDES AND HERBICIDES
The increasing use of pesticides and herbicides in agriculture shows up in the water we drink. Rain and irrigation carry these deadly chemicals down into the groundwater as well as into surface waters -- There are more than 100,000,000 people in the US who depend upon groundwater for sources whole or in part of their drinking water. As our reliance upon groundwater is escalating, so is its contamination. Our own household use of herbicide and pesticide substances also contributes to actual contamination. These chemicals can cause circulatory, respiratory and nerve disorders.
22.214.171.124 TOXIC ORGANIC CHEMICALS
There are 181,000 manmade lagoons at industrial and municipal sites in the US. At least 75 percent of these are unlined. Even the lined ones will leak according to the EPA. Some of these are within 1 mile of wells or water supplies. There is still a lack of information on the location of these sites, their condition, and containments.
Trihalomethanes (THM's) are formed when chlorine, used to disinfect water supplies, interacts with natural organic materials (e.g. by-products of decayed vegetation, algae, etc.). This creates toxic organic chemicals such as chloroform, and Bromodichloromethane. A further word about chlorine: Scientists at Colombia University found that women who drank chlorinated water ran a 44% greater risk of dying of cancer of the gastrointestinal or urinary tract than did women who drank non-chlorinated water! Chlorinated water has also been linked to high blood pressure and anemia. Anemia is caused by the deleterious effect of chlorine on red blood cells.
With the use of high–yielding varieties of crops, the use of fertilizers and pesticides has increased a lot. Excess fertilizers may mix with surface water and may get drained into water bodies (surface runoff). The enrichment of water with nutrients such as nitrates and phosphates that triggers the growth of green algae is called eutrophication. This fast growth of algae followed by decomposition depletes the water body of the dissolved oxygen. As a result, aquatic animals die of oxygen shortage.
11.4 WATERBORNE DISEASES
Most of these municipal pollutants contribute to the increase in disease transmissions of water borne diseases. Waterborne diseases are commonly contracted when bathing in fecal- and urine-polluted streams and canals or can be transmitted by the bite of an insect vector that breeds in polluted waters. Coliform bacteria is often used as indicators of sewage contamination, and the possible presence of microbial pathogens that are hazardous to human health. Several examples of water borne diseases are cholera, typhoid, and dysentery, which occur at a higher rate in the developing countries such as China. Within only a three-month period, there were 1,547 cases with 468 deaths reported in Shanghai and Hongkong due to cholera (Cholera Epidemics in Shanghai & Hongkong, n/d). Not only in does Shanghai and Hongkong deal with cholera, all parts of the Lower Yangtze region, as well as in other provinces in Eastern China, has been indicated with the cholera epidemic. Other waterborne diseases, such as typhoid and dysentery (both forms), .are also epidemic in the Shanghai area due to wastewater pollution (Cholera Epidemic in Shanghai & Hongkong, n/d).
11.5 WASTEWATER TREATMENT
Since wastewater affects the environment in many ways, there must be a solution to treating wastewater that is being discharged from the industrial plants. Currently, there are 400 medium and small sized cities in China, discharging 10 billion tons of wastewater every year (N/A, 1998). Up until now, wastewater pollution in China is a serious concern. Therefore, it is important to treat and recycle wastewater and encourage environmentally sustainable economic development for the future of China.
11.6 PROBLEMS AND OPPORTUNITIES IN CHINA
Within the problems and opportunities, we will observe the problems inflicted by the lack of wastewater treatment facilities throughout China and the possible opportunities that can be made to help alleviate the wastewater pollution problem. In order to propose a viable solution to the wastewater pollution within China, we must observe the components that contributes to the problems caused by the lack of wastewater treatment facilities. These problems include (1) the environment, (2) impacts on society, (3) economic concerns in building the project and (4) the agricultural economic effects on the lack of wastewater treatment facilities within China. In addition to these problems due to the lack of wastewater treatment facilities, there must be a proposal for treating the wastewater efficiently.
讲授，采用问题导入法（Question- based learning），穿插课堂讨论。开始本章内容学习前，给 20分钟学生课堂发言，展示小组合作学习的成果。
2. 课前强调学习目标（Learning Objectives）：
& #8226; Define water pollutant and water pollution.
& #8226; Describe the major effects of water pollution on human health and other living things.
& #8226; Describe the major causes of water pollution and types of sources.
& #8226; Name and summarize the methods of water pollution prevention. i.e. biological wastewater treatment.
& #8226; Understand the importance of water conservation in society’s environmental decisions.
4. 讲授水污染定义(definition)，污染源分类(Point source and Non-point source)，主要污染物及其来源，污染效应(effects of pollution )。
5. 水污染控制方法（Pollution prevention）
第十二章 土地污染（LAND POLLUTION）
Land pollution is the action of environmental contamination with man-made waste on land. Americans generate five pounds of solid waste every day, furthermore creating one ton of solid waste each year. In an average day in the United States, people throw out 200,000 tons of edible food and throw 1 million bushels of litter out of their automobiles. The main human contributor to pollution are landfills. Approximately half of our trash is disposed in landfills. Only 2% of our waste is actually recycled. It is possible that land pollution might also contaminate the air and/or the water or vice versa. In the picture above, for example, some of the trash may end up getting washed into the lake adjacent to it. In another situation, chemical waste may not be disposed of properly and toxic substances may seep into the ground. These seeping chemicals can potentially contaminate a local body of water. It is also possible that these chemicals may give off a toxic vapor, thereby contributing to air pollution as well.
Since the beginning, humankind has been generating waste, be it the bones and other parts of animals they slaughter for their food or the wood they cut to make their carts. With the progress of civilization, the waste generated became of a more complex nature. At the end of the 19th century the industrial revolution saw the rise of the world of consumers. Not only did the air get more and more polluted but the earth itself became more polluted with the generation of nonbiodegradable solid waste. The increase in population and urbanization was also largely responsible for the increase in solid waste.
126.96.36.199 SOURCES OF SOLID WASTE
Source of solid wastes are, in general, related to land use and zoning. Although any number of source classifications can be development, the following categories have been found useful: (1) residential, (2) commercial, (3) municipal, (4) industrial, (5) open areas, (6) treatment, and (7) agriculture. Typical waste generation facilities, activities, or locations associated with each of these sources are presented in table. The types of wastes generated, which are discussed next, are also identified.
188.8.131.52 TYPES OF SOLID WASTE
Solid waste can be classified into different types depending on their source, generally it can divide into the bellow :
Municipal solid waste
Municipal solid waste consists of household waste, construction and demolition debris, sanitation residue, and waste from streets. This garbage is generated mainly from residential and commercial complexes. With rising urbanization and change in lifestyle and food habits, the amount of municipal solid waste has been increasing rapidly and its composition changing. In 1947 cities and towns in India generated an estimated 6 million tonnes of solid waste, in 1997 it was about 48 million tonnes. More than 25% of the municipal solid waste is not collected at all; 70% of the Indian cities lack adequate capacity to transport it and there are no sanitary landfills to dispose of the waste. The existing landfills are neither well equipped or well managed and are not lined properly to protect against contamination of soil and groundwater.
Industrial and hospital waste is considered hazardous as they may contain toxic substances. Certain types of household waste are also hazardous. Hazardous wastes could be highly toxic to humans, animals, and plants; are corrosive, highly inflammable, or explosive; and react when exposed to certain things e.g. gases. India generates around 7 million tonnes of hazardous wastes every year, most of which is concentrated in four states: Andhra Pradesh, Bihar, Uttar Pradesh, and Tamil Nadu.
Household waste that can be categorized as hazardous waste include old batteries, shoe polish, paint tins, old medicines, and medicine bottles.
Hospital waste contaminated by chemicals used in hospitals is considered hazardous. These chemicals include formaldehyde and phenols, which are used as disinfectants, and mercury, which is used in thermometers or equipment that measure blood pressure. Most hospitals in India do not have proper disposal facilities for these hazardous wastes.
In the industrial sector, the major generators of hazardous waste are the metal, chemical, paper, pesticide, dye, refining, and rubber goods industries.
Direct exposure to chemicals in hazardous waste such as mercury and cyanide can be fatal.
184.108.40.206 HEALTH IMPACTS OF SOLID WASTE
Modernization and progress has had its share of disadvantages and one of the main aspects of concern is the pollution it is causing to the earth – be it land, air, and water. With increase in the global population and the rising demand for food and other essentials, there has been a rise in the amount of waste being generated daily by each household. This waste is ultimately thrown into municipal waste collection centres from where it is collected by the area municipalities to be further thrown into the landfills and dumps. However, either due to resource crunch or inefficient infrastructure, not all of this waste gets collected and transported to the final dumpsites. If at this stage the management and disposal is improperly done, it can cause serious impacts on health and problems to the surrounding environment.
Exposure to hazardous waste can affect human health, children being more vulnerable to these pollutants. In fact, direct exposure can lead to diseases through chemical exposure as the release of chemical waste into the environment leads to chemical poisoning. Many studies have been carried out in various parts of the world to establish a connection between health and hazardous waste.
Waste from agriculture and industries can also cause serious health risks. Other than this, co-disposal of industrial hazardous waste with municipal waste can expose people to chemical and radioactive hazards. Uncollected solid waste can also obstruct storm water runoff, resulting in the forming of stagnant water bodies that become the breeding ground of disease. Waste dumped near a water source also causes contamination of the water body or the ground water source. Direct dumping of untreated waste in rivers, seas, and lakes results in the accumulation of toxic substances in the food chain through the plants and animals that feed on it.
Disposal of hospital and other medical waste requires special attention since this can create major health hazards. This waste generated from the hospitals, health care centres, medical laboratories, and research centres such as discarded syringe needles, bandages, swabs, plasters, and other types of infectious waste are often disposed with the regular non-infectious waste.
Waste treatment and disposal sites can also create health hazards for the neighbourhood. Improperly operated incineration plants cause air pollution and improperly managed and designed landfills attract all types of insects and rodents that spread disease. Ideally these sites should be located at a safe distance from all human settlement. Landfill sites should be well lined and walled to ensure that there is no leakage into the nearby ground water sources.
Recycling too carries health risks if proper precautions are not taken. Workers working with waste containing chemical and metals may experience toxic exposure. Disposal of health-care wastes require special attention since it can create major health hazards, such as Hepatitis B and C, through wounds caused by discarded syringes. Rag pickers and others who are involved in scavenging in the waste dumps for items that can be recycled, may sustain injuries and come into direct contact with these infectious items.
It is inevitable that as there are different types of solid waste, there will be varying methods of waste disposal. Briefly most solid wastes are deposited on land as tips or spoil heaps, or as land fill to quarries and mine shafts, or as dumps containing a large range of materials. In addition, small quantities of waste are dumped into the sea.
Certain things that are not needed around the house are kept aside to be sold to the man who buys old items. These items are newspapers, used bottles, magazines, carry bags, old exercise books, oilcans, etc. This is one form of segregation, which is done as a routine in all households in India. Separating our waste is essential as the amount of waste being generated today causes immense problem. Segregation of municipal solid waste can be clearly understood by schematic representation. Certain items are not biodegradable but can be reused or recycled. In fact, it is believed that a larger portion can be recycled, a part of it can be converted to compost, and only a smaller portion of it is real waste that has no use and has to be discarded.
220.127.116.11 RECYCLING AND REUSE
Recycling involves the collection of used and discarded materials processing these materials and making them into new products. It reduces the amount of waste that is thrown into the community dustbins thereby making the environment cleaner and the air more fresh to breathe.
The steps involved in the process prior to recycling include
18.104.22.168 TREATMENT AND DISPOSAL OF MUNICIPA WASTE
As cities are growing in size with a rise in the population, the amount of waste generated is increasing becoming unmanageable. The local corporations have adapted different methods for the disposal of waste – open dumps, landfills, sanitary landfills, and incineration plants. One of the important methods of waste treatment is composting.
Open dumps refer to uncovered areas that are used to dump solid waste of all kinds. The waste is untreated, uncovered, and not segregated. It is the breeding ground for flies, rats, and other insects that spread disease. The rainwater run-off from these dumps contaminates nearby land and water thereby spreading disease. In some countries, open dumps are being phased out.
Landfills are generally located in urban areas where a large amount of waste is generated and has to be dumped in a common place. Unlike an open dump, it is a pit that is dug in the ground. The garbage is dumped and the pit is covered thus preventing the breeding of flies and rats. At the end of each day, a layer of soil is scattered on top of it and some mechanism, usually an earth-moving equipment is used to compress the garbage, which now forms a cell. Thus, every day, garbage is dumped and becomes a cell. After the landfill is full, the area is covered with a thick layer of mud and the site can thereafter be developed as a parking lot or a park.
Landfills have many problems. All types of waste is dumped in landfills and when water seeps through them it gets contaminated and in turn pollutes the surrounding area. This contamination of groundwater and soil through landfills is known as leaching.
An alternative to landfills which will solve the problem of leaching to some extent, is a sanitary landfill which is more hygienic and built in a methodical manner. These are lined with materials that are impermeable such as plastics and clay, and are also built over impermeable soil. Constructing sanitary landfills is very costly and they are have their own problems. Some authorities claim that often the plastic liner develops cracks as it reacts with various chemical solvents present in the waste.
This process of burning waste in large furnaces is known as incineration. In these plants the recyclable material is segregated and the rest of the material is burnt. At the end of the process all that is left behind is ash. During the process some of the ash floats out with the hot air. This is called fly ash. Both the fly ash and the ash that is left in the furnace after burning have high concentrations of dangerous toxins such as dioxins and heavy metals. Disposing of this ash is a problem. The ash that is buried at the landfills leaches the area and cause severe contamination.
Burning garbage is not a clean process as it produces tonnes of toxic ash and pollutes the air and water. A large amount of the waste that is burnt here can be recovered and recycled. In fact, at present, incineration is kept as the last resort and is used mainly for treating the infectious waste.
Organic matter constitutes 35%–40% of the municipal solid waste generated in India. This waste can be recycled by the method of composting, one of the oldest forms of disposal. It is the natural process of decomposition of organic waste that yields manure or compost, which is very rich in nutrients. Composting is a biological process in which micro-organisms, mainly fungi and bacteria, convert degradable organic waste into humus like substance. This finished product, which looks like soil, is high in carbon and nitrogen and is an excellent medium for growing plants. The process of composting ensures the waste that is produced in the kitchens is not carelessly thrown and left to rot. It recycles the nutrients and returns them to the soil as nutrients. Apart from being clean, cheap, and safe, composting can significantly reduce the amount of disposable garbage. The organic fertilizer can be used instead of chemical fertilizers and is better specially when used for vegetables. It increases the soil’s ability to hold water and makes the soil easier to cultivate. It helped the soil retain more of the plant nutrients.
Vermi-composting has become very popular in the last few years. In this method, worms are added to the compost. These help to break the waste and the added excreta of the worms makes the compost very rich in nutrients. In the activity section of this web site you can learn how to make a compost pit or a vermi-compost pit in your school or in the garden at home.
1. 课前明确学习目标（Learning Objectives）：
When you are finished with this session you should be able to:
& #8226; Define land pollution, solid waste, municipal solid waste, hazardous substance and e-waste.
& #8226; Describe the major effects of land pollution on human health and other living things.
& #8226; Describe the major causes of hazardous waste and types of sources.
& #8226; Name and summarize the methods of waste disposal. i.e. landfill, incineration.
& #8226; Understand the importance of land conservation in society’s environmental decisions.
2. 讲授固体废弃物概念（世界上没有真正的废物，只有放错地方的资源）和危险废物概念（definition of solid waste and hazardous waste）
3. 用简洁易记的语言讲授固体废物控制原则：减量化，资源化，无害化。解释“3R”含义：ReduceThe best way to manage solid waste;
Reuse—The better way to manage solid waste；
Recycle — The good way to manage solid waste.
4. 讲授危险废物管理对策 Management of hazardous waste：from “cradle to grave”
5. 令人关注的环境问题：电子废物E-waste， 采用案例分析讲述中国广东贵屿镇拆解电子废物导致的环境问题。
第十三章 噪声污染（NOISE POLLUTION）
Noise pollution can be defined as unwanted or offensive sounds that unreasonably intrudes into our daily activities. It has many sources, most of which are associated with urban development: road, air and rail transport; industrial noise; neighbourhood and recreational noise. A number of factors contribute to problems of high noise levels, including:
Community awareness of environmental noise has increased and there is a higher expectation for commonwealth, state and local government to reduce noise levels.
Although noise is a significant environmental problem, it is often difficult to quantify associated costs. An OECD report on the social costs of land transport identified four categories of impact from transport noise:
Exposure to noise is also associated with a range of possible physical effects including: colds, changes in blood pressure, other cardiovascular changes, increased general medical practice attendance, problems with the digestive system and general fatigue.
There is fairly consistent evidence that prolonged exposure to noise levels at or above 80 dB(A) can cause deafness. The amount of deafness depends upon the degree of exposure.
In metropolitan areas it has been the cause of considerable community concern, particularly since the opening of the third runway at Sydney's Kingsford Smith airport and with the planning of a second Sydney airport. The extent of aircraft noise impact depends on the types of aircraft flown, the number of flights and flight paths.
There are two main sources of noise and vibration relating to the operation of the rail network: the operation of trains and the maintenance and construction of rail infrastructure.
Other significant sources of noise annoyance in Sydney include barking dogs, car alarms, garbage recycling, lawn-mowers, building construction and household noise. A significant proportion of complaints received by local councils, the police and the EPA are related to neighbourhood noise (EPA 1993a). The national noise survey found that noise from barking dogs and road traffic have the greatest impact on residential communities. Noise from barking dogs is of particular concern because it is unpredictable and often happens repeatedly.
13.3.5 INCOMPATIBLE LAND USE
Generally the determination of land use zoning includes the separation of activities which are incompatible due to noise levels. For example, heavy industrial area will be separated from residential areas by light industrial, recreational facilitates and/or retail activities. However, changing land uses over many decades and earlier inappropriate zoning controls have resulted in unacceptable noise levels for some areas and uses.
The Noise Control (Motor Vehicles and Motor Vehicle Accessories) Regulation 1995 prescribes noise levels for classes of motor vehicles and restricts allowable noise levels for vehicles manufactured at variable times depending on the class of the vehicle. In addition, the EPA conducts a noisy vehicle testing program on passenger cars, motor bikes and trucks. However, despite progress in addressing the problem of individually noisy vehicles, the rise in traffic volume has meant an increase in traffic noise overall.
Under the provisions of the Noise Control Act 1975 in NSW the railway system is classified as scheduled premises and as such the EPA has a regulatory role, and seeks to achieve noise targets for rail operations throughout the state to minimise the impact on local residents.
Although the Noise Control Act 1975 has not changed for several years, a number of initiatives have been introduced in the last two years to cover aspects of local noise nuisance not previously dealt with. The regulation under the Act was revised in September 1995 with the creation of separate regulations covering community noise issues and motor vehicle noise. This was followed in 1996 by a regulation controlling marine vessel noise.
1. 课前明确学习目标（Learning Objectives）：
When you are finished with this session you should be able to:
& #8226; Define noise pollution.
& #8226; Describe the major effects of noise pollution on human health and other living things.
& #8226; Describe the major causes of noise and types of sources.
& #8226; Name and summarize the methods of noise control.
2. 用《说文解字》中对“噪”字的解释，引出噪声概念(Definition of Noise)，说明噪声的概念有两种定义角度：
4. 噪声污染控制途径：Source – media – receiver
PART IV TOWARD A SUSTAINABLE SOCIETY
第十四章 可持续发展（SUSTAINABLE DEVELOPMENT ）
CHAPTER 14 SUSTAINABLE DEVELOPMENT
14.1 SUSTAINABLE DEVELOPMENT
Sustainable development is a pattern of resource use that aims to meet human needs while preserving the environment so that these needs can be met not only in the present, but also for future generations. The term was used by the Brundtland Commission which coined what has become the most often-quoted definition of sustainable development as development that “meets the needs of the present without compromising the ability of future generations to meet their own needs.”
Sustainable development ties together concern for the carrying capacity of natural systems with the social challenges facing humanity. As early as the 1970s “sustainability” was employed to describe an economy “in equilibrium with basic ecological support systems.” Ecologists have pointed to The Limits to Growth, and presented the alternative of a “steady state economy” in order to address environmental concerns.
In 1987, the United Nations released the Brundtland Report, which defines sustainable development as ‘development which meets the needs of the present without compromising the ability of future generations to meet their own needs.’
The United Nations 2005 World Summit Outcome Document refers to the “interdependent and mutually reinforcing pillars” of sustainable development as economic development, social development, and environmental protection.
14.2 SCIENTIFIC DEVELOPMENT OUTLOOK IN CHINA
One of the most important national strategies of China is to use scientific development outlook to guild all the development pattern of its economic society.
The basic elements of scientific development outlook can be outlined to be three points as follows:
² to accelerate development;
² to have harmonious development mode touching possible every sides;
² People first.
1. 课前明确学习目标（Learning Objectives）：
When you are finished with this session you should be able to:
& #8226; Define air sustainable development.
& #8226; Describe the current situation and problems of economic development.
& #8226; Describe the major causes of unsustainable.
& #8226; Name and summarize the relationship between sustainable development and scientific development outlook.
2. 问题导入：中国近30年高速发展面临的环境问题（environmental problems）:
1) 大气环境污染 (air pollution)
2) 水环境污染：地表水、地下水、海洋污染(water pollution：surface water pollution , ground water pollution and sea pollution)
3) 土地污染 (land pollution)
4) 生态环境破坏：外来物种入侵(eco-system disturbances)
5) 食品安全问题 (food safety)
6) 健康问题 (Health problems)
3.介绍可持续发展的概念及其背景（definition of sustainable development）,介绍《我们共同的未来》（Our common future）
4.世界范围内的不可持续性 （ non-sustainability）
5.中国的“科学发展观”含义及其对中国未来发展的指导作用。（general meaning of scientific development outlook），组织课堂讨论。