THE POLLUTION PROBLEMS

THE POLLUTION PROBLEMS After studying this chapter, you will be able to: 1. Trace the history of pollution in the world. 2. Identify the major sources of worldwide pollution. 3. Distinguish between toxic pollutants and those that are harmful only to the environment. 4. Describe the main causes of air, water, and land pollution. 5. Enumerate the efforts exerted by some people to help reduce pollution. 4.1. MEANING OF POLLUTION When there is a change in the physical, chemical, or biological condition in the environment which harmfully affects the quality of life, including effects on other animals and plants, then we say that there is pollution in environment. The change is generally brought about by introduction of hazardous substance into the environment. A hazardous substance includes any substance that poses a threat to human health or to the environment. Substances that are poisonous to human beings and animals are called toxicants. Those that harm to the environment may be corrosive, flammable, or explosive. Examples of toxic materials are carbon monoxide (CO), sulfur dioxide (SO 2 ), and the oxides of lead and mercury. Examples of substances that harm the environment include wastes disposed of improperly by industries, nonbiodegradable materials, like plastic, thrown just anywhere; and excessive carbon dioxide (CO 2 ) introduced into the atmosphere. Problems caused by hazardous substances are twofold: first, they cause a wide range of harmful effects on human health such as cancer, damage to the brain, liver, kidney, bone marrow, embryo, skin, gastrointestinal organs, and to the central nervous system; second, these substances can cause long-term or permanent damages to ecosystem. For instance, toxic substances dumped into the water system can cause long-term damage to most of our rivers and lakes. We classify pollution into four types: air pollution, water pollution, land and soil pollution, and noise pollution. Guide questions Name some hazardous substances emitted by vehicles that run on gasoline or diesel fuel. What possible damage can they cause to humans? 4.2. AIR POLLUTION Substances that pollute the air are generally of two types. The first types of air pollutants are those that are directly harmful to humans. They include toxic materials emitted by factories and motor vehicles. The second types of pollutants are those that damage the environment and possibly alter the earth’s climate. Figure 4.1: Environmental pollution 4.2.1. Toxic air pollutants Toxic air pollutants include oxides of sulfur and nitrogen, carbon monoxide, volatile and organic compounds, lead oxide, and benzene. The main source of toxic pollutants is the burning of fossil fuels like gasoline, diesel, and petroleum in power plants, factories, and motor vehicles. Burning of trash also produces toxic pollutants. Figure 4.2: Burning tyres harm to air environment These pollutants are considered toxicants because the human body absorbs these gases together with fine particles into the bloodstream, causing adverse health effects. The most obvious effects are: 1. Breathing difficulties. 2. Increased susceptibility to respiratory infection. 3. Development of chronic lung disease. 4. Worsening of existing heart and lung diseases. 5. Fetal defects and various kinds of cancer. Figure 4.3: Health effects by environmental pollutants 4.2.2. Contributors of common air pollutants The urban and industrialized areas in the world are the greatest contributors of air pollution. Knowing that pollutants are the causes of many bad effects on human health, these should be main causes for alarm by the people in general and by the government in particular. As experienced by the United States, Japan, and the European countries, emission control costs are high, but still, control measures must be undertaken. Otherwise, the cost of man-hours, health care, unproductively, and shorter life span will be more staggering. UNEP and WHO suggested a gradual introduction, and proper maintenance of factories and power plants. Guide questions 1. Explain the two types of air pollution. 2. Is air pollution in your area serious? If it is, do you known if you or some of your neighbors have suffered from of it? What suggestions can you give? 3. Do you know of some steps that the government has taken to reduce air pollution, especially in the Ho Chi Minh City? How effective are they? 4. What are the forms of air pollution that can easily be avoided? 5. Enumerate some general effects of acid rain on the environment. 6. Explain the greenhouse effect. 7. Cite some possible consequences of an increase in global temperature. 4.3. LAND AND SOIL POLLUTION There are two principal sources of wastes responsible for the land and soil pollution. The first one is the solid waste which comes from mining operations. It includes direct waste from the mining of minerals and fossil fuels and those associated with the mining and processing industries. Strip mining not only produces mineral waste that pollutes the soil and streams but also leaves huge scars on the land. The loosening of the soil leads to erosion during heavy rains, causing sediments to settle at the bottom of rivers and lakes. Erosion also adds to the deterioration of the land, making it unfit for agriculture. It also makes the water turbid-cloudy, thick, and dense. Figure 4.4: Pollutants harm to the environment Another type of solid waste is the by-products of agriculture. It includes animal manure and wastes from slaughtered horses and from all forms of crop harvesting. These wastes are generally less polluted because they are spread over wide areas. Also, they are biodegradable, meaning, they return to the soil as nutrients of plants. In excessive amounts, they emit bad odor, which is almost intolerable to human beings. Guide question 1. What are the major sources of water pollution in Ho Chi Minh City? Do you know if something is being done to reduce it? 2. Do you know of other rivers and lakes affected by soil erosion? Where does the eroded soil come from? 4.4. RADIATION AND ITS HARMFUL EFFECTS Radiation is the general term used to refer to a variety of rays to which life on earth is exposed to. These include visible light, infrared and ultraviolet rays, X rays, cosmic rays, and rays from radioactive materials. In a wide sense, any result of radiation energy to a living organism is a biological effect of radiation. This includes normal effects like photosynthesis on plants and vision in animals and also the injurious effect burns, anemia, and cancer on humans and animals. 4.4.1. Historical background When X rays were discovered by the German physicist Wilhelm Conrad Roentgen in 1895, the focus of attention was its possible applications, especially in the field of medicine. The harmful effects were observed one year later. In 1896, Elihu Thomas exposed one of his fingers to X rays and observed the burns caused by these. In the same year, the famous American inventor, Thomas Alva Edition, observed the effects of X rays exposure on one of his assistants, Clarence Dally. Dally hair fell out and his scalp became inflamed. Eight years later, he developed severe ulcers on both hands and arms. They became cancerous and eventually caused his death. The harmful effects of radioactivity were also observed by Pierre Curie, a French chemist and one of the great scientists, in 1906. Burns were produced on the parts of the body exposed to radiation. In 1925, a number of women exposed to paint containing radium became ill with anemia and had lesions in the jawbone and mouth. Some of them developed bone cancer later. Ernest Lawrence - an American physicist who invented the cyclotron, a rich source of neutron - exposed rats to this deadly radiation. He found that fast neutrons are 21/2 times more effective in killing them then slow neutrons. Neutron radiation harmed and killed many people in Hiroshima, Japan, when an atomic bomb was dropped there in 1945. A study was conducted on several hundred pregnant women who survived the Hiroshima and Nagasaki bomb blasts. Their children were medically observed for more than 20 years. Many of them had heads smaller than the normal size, and there was a significant increase in the number of mentally retarded children. 4.4.2. Specific harmful effects of radiation There are many sources of radiation that may cause injury to human beings. The natural sources, like cosmic rays and natural products like granite and monazite sands (an important source of the element thorium), give dosage that are very safe to humans. The artificial sources like medical X rays, high - voltage power supplies, television sets, and luminous dial watches give significant dosage but the effects do not show until after many years. These effects may include lower blood counts, temporary sterility, skin irritations, and on rare occasions, cancer. Figure 4.5: Harmful effect of radiation The very serious health effects come from very massive dozes of radiation from nuclear reactor leaks and explosions of nuclear weapons; such as: The effects of the Hiroshima and Nagasaki explosions and lately, the Chernobyl disaster attested to the veracity of these estimates. Although less damaging, the effects of the nuclear tests in the Nevada desert were also well documented. The bomb that was dropped in Hiroshima killed more than 140.000 of its 255.000 inhabitants, and more deaths occurred later from radioactive radiation. The effects of the Nagasaki blast were similar to that of Hiroshima. In Chernobyl, Ukraine, four nuclear reactors used in generating electricity exploded in April of 1986. The explosion released between 50 and 100 million curies of radioactive material into environment. Within a few months, 29 people died of radiation poisoning and 200 other were estimated to develop cancer in later life. The eventual toll of the nuclear accident has been estimated to be as high as 135000 cancer cases and 35000 deaths. From 1951 to 1962, the United States exploded 126 atomic bomb into the atmosphere at the Nevada test sites. Some civilians and military personnel working at the test sites developed disorders like cancer, heart disease, thyroid dysfunction, and diabetes. The same thing happened to people in southern Utah where winds from the test sites carried radioactive material that affected a lot of people. Tests were subsequently underground to minimize radiation effects and recently, testing of atomic weapons was altogether halter. Guide question 1. What types of radiation are useful to human? What types are harmful? 2. What type of radiation may be useful and harmful at the same time? 3. What events in the past resulted in many deaths due to massive exposure to radioactive materials? 4.7. POLLUTION REDUCTION There is a universal concern for doing something about the production and disposal of hazardous substances. Leading industrialized countries and some leading industrial companies have initiated serious efforts to reduce pollution. 4.7.1. Recycling How to handle society’s toxic chemical waste now ranks among the top environmental issues in most industrial countries. Without concerned efforts to reduce, recycle, and reuse more industrial wastes, the quantities produced will overwhelm even the best treatment and disposal systems [Thảo Nguyên]. The process of converting materials into new products that may or may not resemble the original material is known as recycling. Figure 4.6: The conception of Recycle For example, old newspapers may be recycled into newsprint paper, board for packing, and construction materials for roofing and insulation. The benefits of recycling include the following: 1. It reduces waste. 2. It lowers energy, water, and primary raw material requirements. 3. It reduces both air and water pollution. Imagine the number of trees that would be saved by recycling newspapers. And imagine the amount of trash that would have to be disposed of if plastics, glass, and cans were not recycled. Japan is the leading country that undertakes recycling. The country recycles or reuses about 50 percent of its solid wastes, compared with only 11 percent of the United States and 15 percent of Germany. Moreover, after burning 23 percent of Japan’s trash in waste-to-energy facilities, only 27 percent remains to be disposed of in landfills and by other means. In contrast, 83 percent of solid waste in the United Stated and 55 percent of solid waste in Germany are disposed of by similar means [Hồng Yến]. Table 4.1: Solid waste management in the United Stated, Japan and West Germany Type United States Japan West Germany Recycled or reused 11 50 15 Waste-to-energy 6 23 30 Landfilled or others 83 27 55 Total 100 100 100 Furthermore, Time magazine, in its January 2, 1989, issue, reported that Japan, in 1988, recycled 50 percent of its waste paper, 55 percent of its glass bottles, 66 percent of its beverage and food cans, and converted much of the remaining trash into fertilizers, fuel gases, and recycled metals. Part of the success of Japan’s recycling program is the whole-hearted cooperation of the citizens. The Japanese separate their trash into six classifications to simplify recycling. In contrast, the United Stated in 1986 recovered only 23 percent of its paper products, 9 percent of its glass, and 25 percent of its aluminum. Several countries have followed the Japanese. Glass recycling is fast growing in Europe. The cities of Rome, Vienna, and Madrid have put up recovery plants producing metals, glass, paper, plastics, fibers, and other products. Some third world countries, although on a limited scale, have similarly ventured into recycling. In India, more than a third of urban waste is being composted to produce methane gas, fuel pellets, fertilizers, and animal feeds. China, specifically the city of Shanghai, processes and sells more than 10 percent of its waste for biogas production, fertilizers, and brick and cement manufacture. The city also reprocesses many materials like metals, rubber, plastics, paper, glass, and waste oil. 4.7.2. What you can do The following are things that you can do at home, in school, or in the community to help in the reduction of pollution: 1. Help keeping your school free from unwanted garbage through proper disposal. 2. Help organize or join campaigns in your community to inform the public of the hazards posed by pollution. For example, tricycle drivers may not know that the noise produced by their engines could permanently impair their sense of hearing. 3. Minimize the use of pesticides at home. If you must use them, minimize the potential hazards by (a) making sure people and pets are out of the area during the application and (b) not applying near streams and ponds. 4. Find out what companies are major contributors to pollution. Do not patronize their products and convince others to do the same. 5. Separate wastes that can be recycled. Sell them to local dealers or give them to garbage collectors for their extra income. 6. Help minimize the amount of waste produced in your home. For example, use less plastic wrappers and sell or give old newspapers to dealers who in turn sell them for recycling. 7. Volunteer to help in the information campaign to minimize pollution through proper waste disposal. 8. Generate enthusiasm about programs that would minimize air, water, land, and noise pollution. 9. Eat fewer animal products and consume more grains, vegetables, and fruits that require less energy to produce and therefore create less pollution. 10. Urge your parents to buy household items and appliances that contain no, or less, pollutants. Read the labels carefully before buying. 11. Plant fast-growing trees especially around your house. They provide shade during sunny days and absorb carbon dioxide in the air. They therefore help counteract the greenhouse effect. 12. By reducing energy consumption, you will help lessen environmental damage. The energy you use may come from burning fossil fuels like gas, oil, or, coal. Less energy used means less burning of these fossil fuels. 13. Economize in the use of materials that contribute to the depletion of natural resources. For example, by using less paper, which is a wood product, you help reduce the need for cutting trees. Guide question 1. Cite government efforts to reduce pollution. 2. Explain the good side and the bad side of burning dry leaves under fruit-bearing trees, like mango. 3. What materials are being recycled in Vietnam? 4. How is garbage (solid waste) disposed of in your community? Is it the good way? VOCABULARY Recycling: Processing of material into new products that may or may not resemble the original material. Toxic substance: substance poisonous to human beings and animals. . THE POLLUTION PROBLEMS After studying this chapter, you will be able to: 1. Trace the history of pollution in the world. 2. Identify the major. and land pollution. 5. Enumerate the efforts exerted by some people to help reduce pollution. 4.1. MEANING OF POLLUTION When there is a change in the physical,